Smart grid technologies and application in the sustainable energy transition: a review

ABSTRACT

The smart grid is a product of the advances in computer and communication technology and power electronics that creates a more resilient, reliable and one that supports a two-way flow of electricity and information. The smart grid enables more uptake of the variable renewables like wind, solar and variable loads like the plug-in cars and improves the efficiency of power systems and facilitate several products and services supported by the grid like automatic healing and re-routing of power in case of a fault and demand side management. The deployment and use of smart grids will enhance the realization of shared goals of grid stakeholders, promote energy security, enable economic growth, and help in the mitigation of climate change.

KEYWORDS:

• Smart grids
• grid optimisation
• smart grid technology
• Internet of Things
• smart grid architecture
• Industry 4.0
• sustainable energy
• renewable energy
• non-renewable energy
• energy transition

Highlights

▪	There are five dimensions of energy sustainability namely technical, economic, social, institutional, and environmental.
▪	A smart grid is an electricity grid equipped with advanced communication, automation, and information technology system (IT) which enables real-time bidirectional monitoring and control of electricity and information between sources of power and consumer appliances.
▪	Smart grid technologies are broad and cover many systems and applications today, both as developed and developing technologies. They include smart meters, SCADA and FACTS, PMU, V2G among others.
▪	Smart grids are a typical application of Internet of things (IoT) technology in the electricity sector and if well implemented can resolve several challenges facing the traditional grids like security of supply, outages, high greenhouse gas emissions, and other issues.
▪	Applications for smart grids include renewables integration, smart appliances, distributed generation and related storage, electric car charging infrastructure as well as V2G facilities, transmission, and distribution automation functions, energy efficiency improvement among others.
▪	The challenges facing smart grids include high cost of investment and limited access especially for developing countries having multiple socioeconomic challenges, interoperability of standardisation related issues, cyber and physical security, communication and internet connectivity challenges, and high system security requirements.
▪	Whereas it has a huge capability or potential to transform, it has several challenges to overcome in all dimensions of sustainability. They include high cost, risks to the infrastructure, volatility of related technology, and huge policy and institutional requirements for sustainable adoption and transformation.
▪	Smart grids apply the principles of Industry 4.0 to achieve a power system with better system operation, higher energy efficiency, reduced generation and operation costs, lower greenhouse gas emissions, reduced downtime, reduced power losses, improved energy quality, effective management of generation and storage systems which are key requirements for the energy transition.

Abbreviations

4IR: Fourth industrial revolution; AMI: Advanced metering infrastructure; CPS: Cyber-physical systems (CPS); CAES: Compressed air energy storage; DA: Distributed Automation; DER: Distributed energy resources; DSM: Demand side management; EMS: Energy management system; EHV: Extra High Voltage; EVs: Electric vehicles; GEVs: grid-connected EVs; FACTS: Flexible alternating current transmission system; GHG: Greenhouse gas emissions; HVdc: High voltage direct current; ICT: Information and communication technology; IoT: Internet of things; IIoT: Industrial internet of things; M2M: Machine to man; NTLs: non-technical energy losses;PMS: Power management strategy; RACDS: Resilient. AC Distribution Systems; RES: Renewable energy sources; REPs: Retail Electricity providers; SCADA: The Supervisory Control and data Acquisition System; SLA: Street lighting automation; SH: Smart home; SGIP: smart grid interoperability; SS: Sub-Saharan Africa; SSSC: Static series synchronous compensator; STATCOM: Static synchronous compensator; UPFC: Unified power flow controller; V2B: Vehicle to Building; WSNs: wireless sensor networks; V2G: Vehicle to grid; WAMS: Wide Area Monitoring System

1. Introduction

The energy transition towards sustainable energy systems requires advanced technologies like smart grids (SGs), management systems, and renewable energy generation and storage. To manage the operation of such complex systems requires the integration and coordinating of several power system components like advanced sensors and smart meters as main data sources in the era of big data, wireless communication, and application of the internet of Things (IoT) (Mostafa, Ramadan, and Elfarouk 2022; Rathor and Saxena 2020). Such data acquired should be stored, processed, and analysed to generate the necessary output for efficient deployment of SGs and operation of power station demand and supply while integrating renewable energy and clean sources of energy and demand side management options. Very important in a modern power system is energy fuel efficiency, reduction of emissions, and waste minimisation (Kabeyi and Olanrewaju 2020a; Kabeyi and Olanrewaju 2022a). The benefits from such a modern grid include better asset management, enhanced operations planning, better monitoring and control, reduced cases of voltage instability, accurate prediction, and fault detection in a power system. Such an advanced system also faces several challenges in implementation related to aspects like data uncertainty, data security, data quality, and data complexity (Mostafa, Ramadan, and Elfarouk 2022; Rathor and Saxena 2020).

The electricity grid is undergoing significant changes because of the proliferation of variable renewable energy resources, intelligent sensors, high-speed signal processors, among other developments. SGs can be said to be modern electric power grid architecture having higher efficiency and dependability. SGs present the greatest potential advances in the global sustainable energy transition (Kabeyi and Oludolapo 2020a; Skopik and Smith 2015). SGs were proposed as a result of rapid growth in demand and users thus the need for efficient distribution of electricity, reduced losses, high quality and reliability, and high security of electricity supply (Agung and Handayani 2022; Kabeyi and Olanrewaju 2022b). Energy transformation and sustainability is a global challenge, for many developing countries, facing energy-related issues like wide demand–supply deficiency, over dependency on fossil energy sources, and low access to clean energy. The SG technology can address these challenges and support a smooth transition from traditional to smart energy systems (Bhattarai et al. 2022; Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022c). The power grid consists of transmission lines, substations, transformers, and others meant to deliver electricity from power plants to end users (Kabeyi and Olanrewaju 2022d; US Department of Energy 2018). The grid usually consists of many power plants of different technologies and characteristics, networks, generators, grid operators, and different stakeholders applying different communication levels. The coordination in traditional grids is usually manually controlled (Kabeyi 2022; Kabeyi and Olanrewaju 2020a). The SG uses intelligence for integration of user actions connected to the system like consumers, generators, and other stakeholders for delivery of sustainable, economic, and electric power (Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022d; Vijayapriya and Kothari 2011). An SG makes use of modern communication and computer technology to operate and control the electricity network to better handle potential power system failures (Kabeyi and Olanrewaju 2022b; Kabeyi and Olanrewaju 2022d; Lund et al. 2017). Therefore, an SG is equipped with advanced communication, automation, and information technology systems (IT) that enable real-time bidirectional monitoring and control of electricity and information between sources of power and consumer appliances.

There is a global transformation of the traditional power system that is unidirectional in structure and operation to a configurable and participatory two-way structure where actors or participants can interact with one another (Kabeyi and Olanrewaju 2021a; Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022d). The main motivation for this transformation is advances in communication, power electronics, and computer technology and the increasing need to accommodate the variable renewables and electric cars on the power grid while maintaining maximum reliability, quality of service, with minimum economic and ecological costs, while maintaining maximum safety for equipment and users and always keeping the voltage and frequency values within the permitted range (Kabeyi and Olanrewaju 2022b; Kabeyi and Olanrewaju 2022e; Moreno Escobar et al. 2021).

The traditional electric power grid technology is over 100 years old, and its design is meant to feed electricity from large central power plants using high voltage network, covering considerable distances to deliver power to end users via lower voltage distribution network with little flexibility (Kabeyi and Olanrewaju 2022b; Kabeyi and Olanrewaju 2022d). Over years now, electricity demand has grown rapidly mainly due to social-economic development and industrial growth but the supply mainly comes from cheap traditional sources of energy like coal, gas, and petrol that are associated with the release of greenhouse gas emissions (GHG) to the atmosphere that is responsible for climate change (Kabeyi and Olanrewaju 2022c; Ponce-Jara et al. 2017). The electricity grid is being modernised towards advanced consistency, less costs, and greater efficiency through more uptake of renewable energy, advanced control technology and two-way communication. There has been a growing need for substation modernisation to cope with the fast growth of the grid, growing consumer needs, and technological innovations leading to grid transformation. The SG can help accomplish these technological reformations across the grid in power n generation, transmission, and distribution, through more use of sensors, communication, and computers (Saumen, Alok Kumar, and Pradip Kumar 2021).

Therefore, an SG marks a shift from centralised power generation to decentralised power generation. SGs seamlessly integrate the three power system functions of generation, transmission, and distribution are integrated evolving the grid into an integrated smarter system. The SGs facilitate the integration of all forms of power generation and convert a consumer into a producer and consumer (prosumer) enabling households to generate and store electricity both for sell and own use courtesy of the two-way power flow and communication facilities (Kiran and Rao 2018).

The SG can empower customers with real-time control and the choice between storing, generating, and consuming electricity based on prevailing cost, availability of energy, and demand for electricity. Through demand response (DR), SGs enable customers to change their electricity consumption pattern by shifting or reducing their consumption from peak to off-peak hours thus making power flow more interactive, efficient, customer friendly, and more environment friendly (Kiran and Rao 2018). The concept of SG is an addition to existing or prospective smart meters which allow accurate energy flow analysis for power utilities, increase uptake of renewable energy sources, and facilitate sharing of energy with increased system throughput (Mysiakowski 2021). The modern should simultaneously address the challenges of increasing environmental pollution, greenhouse gas emissions, and diminishing fossil fuel reserves and climate change (Rathor and Saxena 2020). SGs facilitate decentralised decision making and enable active participation of prosumers and other assets not owned by the grid. They additionally facilitate monitoring of energy flows, manage prosumers’ energy supply and demand changes which may be rapid to attain local energy balance, and optimise the electricity flows in the power systems (Antal 2021).

The traditional grid was designed to connect far away consumers of electricity from central power plants using a rigid one-way power flow arrangement. On the other hand, SGs are designed to provide a two-way flow of power and information. This has been made possible by developments and advances in information technology, communication, and power electronics technology making it possible to accommodate new energy carriers, as well as decentralisation of power generation, and higher uptake of variable energy sources like wind and solar and variable loads like electric vehicles. This will enable higher access to electricity over and beyond the capability of the traditional grid (Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022c; Kabeyi and Oludolapo 2020a). Today, an ideal electricity grid ought to be a two-way system with power generation from a mixed multitude of big, medium, and small, distributed plants supplying grid power in an optimised mix mode (ABB 2008; Prasad 2014). This will facilitate maximum and optimum absorption of variable and intermittent renewable sources of energy like wind and solar have huge potential to contribute to the grid as sustainable and renewable energy sources needed for the global energy transition (Kabeyi and Olanrewaju 2021b; Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022f; Kabeyi and Oludolapo 2020a).

The overall objective of this study is to give an insight into SG technology and the role that SGs can play in the sustainable energy transition. This study examined the role of the SGs in the transition from fossil-dominated electricity generation energy mix and supply using the traditional grids to the renewable energy resource-dominated energy mix with variable sources like wind and solar playing a leading role on the generation side, while variable loads like V2G and G2V having a significant proportion of the load. The study involved the review of current literature on SGs technology and sustainable energy and electricity from peer-reviewed and published journal papers, conference papers and proceedings, and technical reports covering SG systems.

1.1. Problem statement

Many countries especially developing countries are facing energy transformation and sustainability challenges like broach supply–demand gap for electricity and other energy resources, extensive dependence on fossil fuels and low access and penetration of clean energy (Bhattarai et al. 2022; Kabeyi and Olanrewaju 2021b; Kabeyi and Olanrewaju 2021c; Kabeyi and Olanrewaju 2022g; Kabeyi and Oludolapo 2021a). It is established globally that these challenges can be addressed and facilitate the transition to smart energy systems from traditional systems using the SG, yet the rate of deployment of the SG remains low (Bhattarai et al. 2022). By operating the conventional grid, the electricity utility providers have little and at times no insight into electricity users consume power. Within the traditional grid, the operation by the utilities is purely based on prevailing demand, and in case of demand uptick, operators simply send more power to the grid (Kabeyi and Olanrewaju 2022d; Particle Industries 2022). The world has witnessed significant advances in technology which includes the development of better electricity carriers, variable electricity pricing, advances in energy storage technologies, decentralisation of generation and increasing contribution of variable renewable sources (VREs) energy to grid electricity as well as the electrification of transport which introduces variable and unpredictable loads which are challenging for the traditional electricity grid (Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022c; Kabeyi and Olanrewaju 2022d). The challenges facing the energy transition are to modernise the grid, innovate, adopt new technologies, develop tomorrow's solutions, and serve local and territorial communities (Kabeyi and Olanrewaju 2022b; Kabeyi and Olanrewaju 2022h; Ourahou et al. 2020). There is a need to modernise the electricity system to cope with the energy changes and address the limitations of the traditional grid. The integration of new information and communication technologies into the grid makes it communicative allowing for diverse actors’ involvement in the electricity system, while at the same time facilitating a more efficient, economically, safe electricity system (Kabeyi and Olanrewaju 2022d; Ourahou et al. 2020). Upgrading of the electricity grid is necessary to realise energy-saving schemes which empower users and support and environmental conservation (Saumen, Alok Kumar, and Pradip Kumar 2021).

There is growing demand for sustainable solutions to the electricity-related environmental pollution, high power system losses, high contribution of fossil fuel sources to grid electricity energy mix which is the characteristic of traditional grid systems and hence the need to increase the share of variable renewable energy sources like photovoltaics and wind, use of fuel cells, growing need to integrate storage systems and use of plug-in electric cars as pathways to sustainable energy transition (Azzouz, Shaaban, and El-Saadany 2015; Conejo, Morales, and Baringo 2010; Rathor and Saxena 2020). The world community is increasingly concerned about the looming consequences of greenhouse gas emissions most of which are related to electric power generation and fossil fuel-based transportation (Beaudin and Zareipour 2015). With the ever-growing global electricity demand, the multiple effect is an increase in the cost of energy, diminishing fossil fuel reserves and hence more demand for the widely available variable renewable energy sources like wind and solar (Edvard 2022). As a move to address the challenge of global warming and limit the temperature rise to less than 2^oC, as stated in the Paris Climate Agreement of 2015, the global share of renewable energy in power generation should be increased to 85% in 2050 from 33.3% in 2018 (International Renewable Energy Agency 2019).

The energy sector is necessary for the development and growth of the economies of all countries (Boden, Marland, and Andres 2017; US Department of Energy 2018). The continuous growth of the world economy and population contributes to the ever-increasing energy demand hence the continued and increasing use of fossil fuels like coal, oil, and natural gas whose use is associated greenhouse gas emissions, energy insecurity, depletion of fossil fuels reserves, geopolitical, social, and political conflicts over resources and increased price and supply instability (Kabeyi and Olanrewaju 2021a; Kabeyi and Oludolapo 2020a). These scenarios have created unsustainable situations and threats to mankind and his environment (Kabeyi and Olanrewaju 2022a; Owusu and Asumadu-Sarkodie 2016). As a solution renewable energy resources should be used as substitutes for fossil fuels but total replacement may not be feasible in the near future, hence the need for optimum mixing of energy sources and modernisation of the electricity grid to realise this objective (Kabeyi and Olanweraju 2022i; United nations 2015). The electrification of industrial, domestic energy applications, and transport sector are also seen as major pathways in the sustainable energy transition which call for smarter grids for more efficient and effective control of electricity as an energy carrier. There is a need for self-regulation and self-reconfiguration of electric power systems by equipping power systems with the relevant intelligence and technical capabilities to improve the performance, quality, and efficiency of electric power systems (Kabeyi and Olanrewaju 2021a; Kabeyi and Olanrewaju 2022a). It is this desire that incentivised the development of the SG power system by equipping the power system with modern computer and communication technology to achieve network stability (Kabeyi 2020a; Lund et al. 2017). The main challenge is that the traditional grid connection topologies are not quite adaptable and cannot cope with the level of dynamism of current electricity demand and supply. There is a need for an intelligent power system to cope with the current characteristics of variable load demand, e.g. from electric cars and variable supply like supply from variable wind and solar energy sources (Kabeyi and Olanrewaju 2022j; Kabeyi and Olanrewaju 2022k; Moreno Escobar et al. 2021). Additionally, about 10% of the total grid power is lost to transmission and distribution of which 40% is lost at the distribution side alone in the traditional grid (Kabeyi and Olanrewaju 2022l; Rathor and Saxena 2020).

Many electricity systems around the globe are transiting from centrally controlled conventional grids to modern grids whose operation is influenced and controlled by the market dynamics for investment decisions, operational stability, and reliability of power generation and supply (Lasseter 2002). Renewable energy resources like wind and solar have significant potential in power generation but they face significant challenges in their exploitation due to their intermittence and variability in supply and availability (Kabeyi and Olanrewaju 2022d; Kabeyi and Olanrewaju 2022e). The energy transition from non-renewable to renewable sources continues to face significant technical and non-technical barriers. These barriers may vary from one country to another and from one energy resource to another depending on the level of technology required, environmental impacts, and policy initiatives put in place by different countries (Kabeyi 2020b; Kabeyi and Olanrewaju 2022b). The challenges include poor governance, technical limitations, high energy cost, energy affordability, and organisational or community resistance to change (Kabeyi 2019a; Owusu and Asumadu-Sarkodie 2016). The main challenges in the sustainable transition to a sustainable grid are limited access to reliable, affordable and adequate renewable and continued reliance on fossil fuels in power generation and other energy applications like transport (Jefferson 2020) and hence the need to shift to renewable low carbon sources of energy for grid electricity generation (Kabeyi and Olanrewaju 2022a; Kabeyi and Oludolapo 2020a).

In the view of these challenges to the development and consumption of renewable energy resources for electricity generation, the use of technology in electricity generation and distribution can go a long way in optimising of renewable energy penetration to the electricity grid (Kabeyi 2020a; Kabeyi 2020b; Kabeyi and Olanrewaju 2022m). This brings to focus the need for SGs for sustainable use of both renewable and non-renewable energies for grid electricity in an optimised interconnected system (Kabeyi and Oludolapo 2020a). Sustainable development requires social, environmental, and economical perspectives, for development activities. This study explores the role of SGs as opposed to the traditional grid to achieve sustainability and sustainable use of energy resources for electricity generation and supply to guarantee energy security, socioeconomic development, mitigation against climate change and protection of the environment while remaining economically competitive and how SGs can be used to realise sustainability (Kabeyi and Olanrewaju 2021a; Kabeyi and Olanrewaju 2022a; Kabeyi and Oludolapo 2020a).

1.2. Rationale of the study

Energy transformation and sustainability is a challenge for many countries, particularly the developing countries. These challenges include a wide demand–supply gap, over-reliance on fossil fuels, and low access to clean energy (Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022e; Kabeyi and Olanweraju 2022i). The increase in electricity demand has introduced challenges in generation and distribution with increasing requirements for greater reliability, flexibility, efficiency, security, automation and both energy and environmental sustainabilities and use of SGs can add significant value (Majeed Butt, Zulqarnain, and Majeed Butt 2021). The SG technology has the potential ability to enable a smooth transition to smart energy systems from traditional systems leading to enhanced energy security and access to sustainable energy (Bhattarai et al. 2022; Smale, van Vliet, and Spaargaren 2017). A modern electricity grid should satisfy three challenges, namely renewable energy, electric vehicles, and control of energy demand while at the same time improving the quality of electricity supply and reducing costs. The power utility role of facilitator of the energy and acts as a federator (Ourahou et al. 2020).

Over 400 billion metric tons of carbon have been released into the atmosphere from fossil fuels combustion and cement production since the year 1751. Of these emissions, about 200 billion metric tons came from fossil fuel combustion emitted since the late 1980s. In the year 2014, the global fossil-fuel carbon emissions were estimated at 9855 million metric tons accounting for about 0.8% increase in emissions over the 2013 emissions level which implied 3 years of modest growth in missions (Jefferson 2020; Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022d). The emissions trend shows that global CO₂ emissions from fossil-fuel combustion and cement production have more than doubled in a decade to account for about 5.8% of Kabeyi and Olanrewaju (2022f), Kabeyi and Oludolapo (2020a). Gas flaring, which accounted for roughly 2% of global emissions during the 1970s, now accounts for less than 1% of global fossil-fuel releases (Boden, Marland, and Andres 2017; Kabeyi and Olanrewaju 2022m; Kabeyi and Olanweraju 2022i). This shows that fossil fuel combustion and related activities for power generation and cement production in the manufacturing industry are leading polluters of the atmosphere and their use need to be limited by the promotion of decentralised generation and use of renewable energy resources (Kabeyi and Olanrewaju 2021d; Kabeyi and Olanrewaju 2022n; Kabeyi and Oludolapo 2020b). This can be achieved using SGs (Kabeyi and Olanrewaju 2022b; Kabeyi and Olanrewaju 2022c; Kabeyi and Olanrewaju 2022m).

The traditional grid was designed to connect large central power plants with electricity distribution through a high-voltage transmission. Over the years, the traditional grid grew from a transmission system with local and regional grids into a large, interconnected network system whose management is in the form of centrally coordinated operating and planning procedures (Henderson, Novosel, and Crow 2017; Kabeyi and Olanrewaju 2022a). The notable limitation of the traditional grid is that it only remains effective where the peak demand and energy consumption grow at predictable rates. The technology is effective in a relatively well-defined regulated operational environment making it difficult for the traditional grid to handle variable, and unpredictable load like variable renewables and grid-connected electric vehicles (Henderson, Novosel, and Crow 2017; Nguyen et al. 2020).

Increased decentralisation and demand for microgrids (MGs) have increased demand and hence the need to increase the share of renewable energy resources which are variable and intermittent in supply. The electrification of transport has also led to an increase in the use of electric vehicles which need charging facilities that introduce significant number of variable loads to the grid while at the same time provide an opportunity for V2G (vehicle to grid power supply) which is also variable. The grid must be highly resilient and smarter to effectively handle these variable electric loads and energy sources (Kabeyi and Olanrewaju 2022o; Kabeyi and Olanrewaju 2022p; Rathor and Saxena 2020). The demand for a resilient and intelligent power grid is further compounded by the growing popularity of variable electricity billing, for efficient demand side management which additionally creates demand for smarter grids (Conejo, Morales, and Baringo 2010; Prasad 2014; Rathor and Saxena 2020). The use of SGs has a role in the energy transition as they additionally reduce emissions by facilitating efficient power distribution which ultimately reduces greenhouse gasses and pollutants like NOx and Sox for power plants (Kabeyi 2019a; Majeed Butt, Zulqarnain, and Majeed Butt 2021).

The traditional electricity grids have challenges related to managing expansion and operation of the transmission, generation, and distribution in a dynamic and complex environment where significant variable and unpredictable electric loads and sources of generation have become increasingly important for the energy transition (Kabeyi and Olanrewaju 2022q; Kabeyi and Oludolapo 2020a). Amid these concerns, opportunities, and challenges, for a highly resilient and flexible grid system will increase the absorption of abundant but variable renewable energy sources and desirable electrification of transport systems hence contributing to national and global energy electricity security (Kabeyi and Oludolapo 2020a; Kabeyi and Oludolapo 2021b). Therefore, the future grid must connect all new sources of electricity, including renewables, extend grid coverage over thousands of kilometres deep into the interior and rural settlements with small but widely distributed load demands and limited related transmission and distribution losses. The solution to this challenge is a stepped-up investment to modernise and digitalise electricity networks to guarantee secure, reliable, and affordable power systems in the current energy transition to clean and renewable sources of power (International Energy Agency). It is for these reasons that SGs have shown a huge potential in transforming energy systems towards sustainability.

The world has experienced considerable technological advances in electricity generation and supply, but new challenges continue to emerge particularly with the absorption of variable and intermittent energy sources (Henderson, Novosel, and Crow 2017; Kabeyi and Olanrewaju 2022d). This has led to the continuous upgrading of the new technologies which include the development of high voltage equipment, advances in computerised monitoring, control, protection, and management of the grid with real-time operation and maintenance, increasing efficiency and cleanliness of power plants, advances in power electronics in the form of flexible alternating current transmission systems (FACTS) and advances in high voltage direct current (HVdc). These developments have created a conducive infrastructure and environment for transforming the traditional grid to an intelligent or SG (Henderson, Novosel, and Crow 2017; Kabeyi and Oludolapo 2020a).

Concerns about greenhouse gas emissions and climate change are now at the centre of the international energy policy discourse (Kabeyi 2020b; Kabeyi and Olanrewaju 2021b). However, there are too many barriers to the deployment of energy that meets the sustainability requirements like competitive and reliable fossil fuels leading to fossil fuel domination of the energy mix (Kabeyi 2019b; Kabeyi 2020a; Kabeyi and Olanrewaju 2022f). Through their ability to increase and uptake of renewables by the power grids, SGs can help reduce emissions and hence global warming potential and increase power system resilience and reliability (Nasir 2021; Ponce-Jara et al. 2017).

The growing demand for electricity and development of SGs are providing significant opportunities for home-based energy management (Beaudin and Zareipour 2015). Electricity grid reliability is the measure of the ability of the grid to meet customer needs and expectations. This makes grid reliability a very important dimension of the sustainability of the power system grid (Kabeyi and Olanrewaju 2021e; Kabeyi and Olanrewaju 2022k; Kabeyi and olanrewaju 2022r). The security of energy supply requires a flawless and errorless power system that guarantees a continuous supply of electricity to consumers. Therefore the SG is the ultimate choice due to its ability to detect faults, prevent failure and allow self-healing of the power system (Majeed Butt, Zulqarnain, and Majeed Butt 2021). On the other hand, the traditional grid has challenges with the integration of renewable resources, support, and integration with MG and DR capability. The main drivers of demand for SGs are ever-growing electricity demand and supply, growing level of variable loads, and variable renewable energy sources in grid power generation (Kabeyi and Olanrewaju 2022m; Majeed Butt, Zulqarnain, and Majeed Butt 2021). This is because SGs can monitor, store data, and initiate real-time corrective measures to these challenges (Kabeyi and Olanrewaju 2021a; Kabeyi and Olanrewaju 2022d; Majeed Butt, Zulqarnain, and Majeed Butt 2021). This study examines the role that SGs can play in the sustainable energy transition to a stable, safe, and reliable low-carbon and renewable energy-based electricity mix making the study an important contribution to the sustainable energy transition.

1.3. Benefits of SGs

The SG technology presents an unprecedented opportunity to transition the energy industry into an era of high availability, reliability, and efficiency. This will enhance the economic and environmental health of both developed and developing world economies (Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022b; Kabeyi and Olanrewaju 2022h; Kabeyi and Olanweraju 2022i). There is a need to carry out testing, consumer education, technology improvements, standards development and regulations, and information sharing between energy projects to ensure that the benefits derived from the SGs are realised during the energy transition period (Kabeyi and Olanrewaju 2022d; Kabeyi and Olanrewaju 2022e; Kabeyi and Olanrewaju 2022s). The benefits of SG include:

1. SGs enable more efficient power transmission.

2. They facilitate the quicker restoration of electricity in case of power supply disturbances.

3. SGs enable a reduction in operations, maintenance, and management costs for electricity utilities, which lowers power costs for consumers.

4. The use of SGs can reduce peak demand which leads to delayed or suspended expansion of capacity leading to reduced or lower electricity rates.

5. Increased integration of large-scale renewable energy systems

6. They facilitate more efficient and better integration of customer–owner power generation systems, including renewable energy systems thus converting electricity consumers of a traditional grid to prosumers.

7. There is improved energy security using SGs due to increased decentralisation of generation which enables increased use of local energy resources, most of which are renewable sources like wind, solar, and biomass.

8. Facilitate the integration of renewable energy sources in the electricity network.

9. Support or facilitate new uses of electricity, like electrification of transport or development of electric vehicles.

10. Facilitate the emergence of innovative energy efficiency solutions at the community level like the development of smart cities or smart neighbourhoods (Kabeyi and Olanrewaju 2022b; Kabeyi and Olanrewaju 2022d; U.S Department of Energy 2022).

Power supply with the traditional grid is characterised by electricity disruption like blackouts which can have negative impact on almost all industries and services like banking, traffic, communications, water, and security. Worse is a power outage in winter, which can leave consumers without heat. With an SG, resiliency is added to our electric power system making it better prepared to handle or accommodate emergencies like severe storms, earthquakes, and terrorist attacks (Ourahou et al. 2020; U.S Department of Energy 2022). The SG is managed in a more flexible way to manage constraints like variability and intermittence of energy resources and support of variable loads like electric vehicles (Kabeyi and Olanrewaju 2022d). The constraints can change the current system, in which real-time equilibrium is ensured by adapting production to consumption, to one in which adjustment is done more by demand converting the consumer to more important actor in power system control (Kabeyi and Olanrewaju 2022f). Therefore SGs combine a demanding business environment and new technological advances that can transform the energy sector (Ourahou et al. 2020).

1.4. Novelty of the paper

The development of carbon neutral solutions to global power generation is more imperative today than ever before as electricity demand continues to grow with most of it being catered for by polluting fossil fuels. The blackout across Texas in the year 2021 is one among many incidents that exposed the serious challenges of the traditional electricity grids. As the world focuses on deploying low-carbon energy solutions, this study identifies SG technology not just as a technological advancement, but as a very important tool for sustainable energy transition (Particle Industries 2022). Although interconnected devices offer a complex energy crisis puzzle, the authors have tried to tactfully profit from the puzzle and underlying technological advances in power electronics and communication technology and for the socio-economic transformation of humanity. The study has explicitly demonstrated how the IoT has become a significant tool for the for the energy transition within the framework of SG technologies (Particle Industries 2022). Several studies have so far been carried out on various aspects of SGs and their role in the energy transition to renewable energy sources. In their work, Bhattarai et al. (2022) investigated the current potential application SG technology in Nepal. In the study, researchers explored the needs and identified opportunities for Nepal and other developing countries like increased use of renewable energy, smartening of various MGs and electrification of transport. In the study on sustainable global energy transition, Kabeyi and Olanrewaju (2022a) and Kabeyi and Oludolapo (2020a) identified SGs as a solution to the challenge of handling variable renewables like wind and solar and that use of SGs will enhance energy security and reduce reliance on fossil fuel sources of energy in power generation. As opposed to previous studies, this study takes a holistic view of the subject of SGs and how they can aid in the sustainable energy transition. The study analyses SG technologies within the five dimensions of energy sustainability, namely technical, social, economic, environmental, and institutional sustainabilities. The findings of this study will guide policymakers and planners in the energy sector, particularly electricity in developing sustainable electricity grids in line with the Paris agreement and other energy sustainability protocols.

2. SG architecture and functionalities

The SG, like the traditional grid, is a network of electricity infrastructure serving power to residential, business, or commercial and industrial consumers at the right quality and safety. The SG refers to the next generation of those systems equipped with advanced communications technology and connectivity for a smarter usage of energy resources (ABB 2008; Kabeyi and Olanrewaju 2020a; Kabeyi and Olanrewaju 2022d). Several technologies constitute the IoT-enabled grid, e.g. wireless devices including radio modules, sensors, gateways, or routers to assist the power system operation through the provision of sophisticated connectivity and communications, monitoring, and control in a way that helps consumers make better energy consumption decisions while saving electricity, reduce expenses and even act as electricity suppliers or prosumers (Kabeyi and Olanrewaju 2020a; Kabeyi and Olanrewaju 2022d; Kabeyi and Olanrewaju 2022t; Ramanath 2023).

The operation of SGs involves the use of hardware, software, and technologies that facilitate the identification of power imbalances and enable instant correction to restore quality, increase reliability, safety and reduce energy costs (Moreno Escobar et al. 2021). For this to happen, the components have to communicate with each other and work harmoniously means modern computer software (Majeed Butt, Zulqarnain, and Majeed Butt 2021). The traditional grid is made intelligent by the addition of automated monitoring and control systems with a two-way communication capability (Kabeyi and Olanrewaju 2022a). The SG concept for the conventional power grid is equipped with modern and automated features to enhance the reliability and sustainability of electricity systems. SG is viewed as a grid with an embedded layer of information that facilitate a two-way communication between controllers and local actuators and logistic units in response to changing power system conditions mainly in terms of power generation and its supply or transmission and distribution (Zhang, Huang, and Bompard 2018)

Overall, the SG system can process and store data, and communicate the same to other devices and users for application in making critical decisions and execute the system functions based on prevailing circumstances as analysed or processed by the power system intelligence (Majeed Butt, Zulqarnain, and Majeed Butt 2021). Therefore, the conventional grids just transmit and distribute power to consumers from generating centres, but SGs can accommodate the reverse flow of power, information, and make critical analyses and decisions (Kabeyi and Olanrewaju 2022d; Majeed Butt, Zulqarnain, and Majeed Butt 2021).

2.1. Definitions and historical perspectives

The term SG was used in the year 2005 for the first time by Amin and Wollenberg in their paper entitled ‘Towards a Smart grid’. Amin and Wollenberg proposed practical methods, technologies, and tools that allow electricity grids and other infrastructures to self-regulate, and automatically reconfiguration in the event of disturbances, failures, and threats (Bhattarai et al. 2022). Although Amin and Wollenberg did not provide a formal definition of SG, it is implied in the paper that an SG is a network that makes use of modern computer and communication technology to realise a grid that can manage failures (Bhattarai et al. 2022; Lund et al. 2017). The use of SGs leads to better integration of fluctuating renewable energy, creates environment for involving the consumer in active operation through the application of incentives that enable flexible demand, and provision of effective two-way information and communication systems (Kabeyi and Olanrewaju 2022d; Lund et al. 2017).

The SG can be viewed as a combination of new technological developments and a more demanding business environment. According to the Smart European Technology Platform, an SG is defined as ‘an electricity network which intelligently integrates all users’ actions, i.e. consumers, generators, and prosumers whose objective is to efficiently deliver sustainable, economic, and secure electricity. The US Department of Energy defines an SG as a grid that applies digital technology to improve power system reliability, efficiency, and security right from power generation, through the delivery systems to power consumers with the growing use of distributed generation and energy storage resources (Bhattarai et al. 2022; Ourahou et al. 2020). The SG is the state-of the-art concept and infrastructure defined within the limitations of the electric power sector, particularly with regard to the integration of fluctuating renewable energy within the power sector (Kabeyi and Olanrewaju 2022a; Kabeyi and Oludolapo 2020a; Lund et al. 2017).

The SG development has been an evolutionary process that took place over time in a process referred to as ‘smartening the grid’ or ‘modernising the grid’. The deployment of SG technologies is an enabler to the delivery of clean, economic, and reliable electric power to end users in a secure, reliable, clean, economic manner (Kappagantu, Daniel, and Suresh 2016; UNECE 2016). The International Energy Agency (IEA) defines an SG as an electricity network that applies digital technology as well as other advanced technologies to manage, monitor, and control the transport transportation of electricity from power plants to end-users. The SGs co-ordinate the ability and capability of power system stakeholder and equipment like power plants, utility companies, consumers or end-users and stakeholders of the electricity market to enable efficient operations, minimise costs and minimise the environmental impacts as it maximises power system reliability, stability, and resilience (UNECE 2016).

The European Commission (EC) defines an SG as an energy network that monitors energy flows and adjusts to supply and demand changes automatically. SGs incorporate smart metering system and provide real-time information, to both consumers and suppliers in a two-way communication(Bhattarai et al. 2022). With smart meters, consumers can adjust their consumption in line with energy prices throughout the day, thus reducing energy bills by ensuring more consumption is done when processes are low (UNECE 2016).

According to the United States Office of Electricity Delivery & Energy Reliability (USA OE) as cited in UNECE (2016), an ‘SG’ is a class of technology used by power utility companies to deliver using computer-based remote control and automation. The systems use two-way communication technology and computer capability. SGs are applied in electricity networks, right from power plants, wind farms, to the users in homes, industry, and businesses, which leads to improved energy efficiency on the grid and users. According to the International Electrotechnical Commission (IEC), an SG refers to a concept of modernising the power grid. By the addition of SG technologies makes the grid more flexible, more interactive and the grid gets the ability to give real time feedback. It intelligently integrates the interests and actions of all grid users namely generators, consumers, and prosumers to efficiently deliver power that is sustainable, secure, and economical. Through innovative products and services with intelligent monitoring, communication, control, and self-healing facilities, an SG makes it efficient and economical to connect different power plant technology and sizes of generators, allows consumers to be active participants and play a role in system optimisation, provides useful data and information and choice of power supply, which reduces the environmental impact the entire power system leading to safe, reliable and secure electricity supply (UNECE 2016). On the part of the Japan Smart Community Alliance (JSCA) which represents the views of the Smart Communities, an SG promotes greater use of renewable energy and idle energy resources and local generation of heat energy for local consumption. Therefore, SGs contribute to energy self-sufficiency leading to reduced greenhouse gas emissions. They also provide a stable power supply and optimise overall grid operations from power generation to end use (UNECE 2016).

2.2. Characteristics and functions of smart grids

The electrical grid spans kilometres of terrain supplying power to industries, businesses, homes by connecting electricity customers to power generating stations. The grid is arguably the biggest stationary machine ever assembled by mankind (Saumen, Alok Kumar, and Pradip Kumar 2021). One of the greatest challenges facing the traditional grid is the risk of impaired consistency and security of power supply load when renewable electricity is disrupted. It is important to improve the capacity of the transmission and distribution structure to accommodate growing distributed energy resources (DERs) (Kabeyi and Olanrewaju 2022a; Saumen, Alok Kumar, and Pradip Kumar 2021). The modernisation of the grid is a development guided by finances, universal rules, and technological advances in ICT. Currently, desirable grid improvements should ensure the supply of green and sustainable energy and electricity. The SG which is an improved grid works with a two-way power flow (Kabeyi and Olanrewaju 2022d; Kabeyi and Oludolapo 2020a; Saumen, Alok Kumar, and Pradip Kumar 2021).

SGs can be used to address the growing social, economic, and environmental challenges encountered in the delivery of energy resources and generated electricity. This is achieved through increased awareness of the operation of the system and informed participation in SGs which improves end-use efficiency while optimising utility of network assets and increasing the resilience of the grid (International Energy Agency 2011; Kabeyi and Olanrewaju 2022d). The use of SGs will also enable efficient integration of variable renewables and electric vehicles and the provision of new grid services and new products. SGs coordinate the abilities and needs of all generators, grid operators, consumers, and stakeholders of the electric power market. This coordination function increases system efficiency, reduces costs, wastage, and environmental impacts, and maximises system reliability, stability, and resilience. These optimisations by the SGs are achieved by applying digital and other advanced technologies in monitoring and management of electricity transmission and distribution to meet the variable power demands of consumers. Therefore successful deployment and use of SGs will enable the global community realise shared goals securing energy security, economic growth and development and mitigation of climate change (International Energy Agency 2011; Kabeyi and Olanrewaju 2022b).

The SG technologies and their applications prescribe power system that is significantly different from common or traditional power system (Jackson 2014). The basic characteristics of SGs that define the new model of the grid are.

1. They are equipped with extensive metering, control, and communications throughout the distribution system with the ability to metre individual customers and grid equipment like switches, transformers, capacity banks, voltage regulators, and others across the distribution system and have the ability to relay the information back to the utility through the communication system (Jackson 2014; Kabeyi and Oludolapo 2021a).

2. Two-way communication

   SGs are equipped with Two-Way Customer Communication and Power Flows as opposed to the one-direction flow to the customer alone in the traditional system and but the feedback of information is in the opposite direction to the utility often on a monthly basis. The SG supports frequent and on-demand two-way flow of both power supply and information (Jackson 2014; Kabeyi and Olanrewaju 2022c; Kabeyi and Olanrewaju 2022m; Kabeyi and Olanrewaju 2022o; Kabeyi and Olanrewaju 2022u).

3. Stakeholder Participation and engagement

   Stakeholders in a grid environment like the customers can participate actively in the grid operations. Customers can supply their own produced power from local resources like cogeneration, wind, solar and biogas and they can respond to signals from the utility to reduce peak power consumption when the system is under stressed (Jackson 2014). Therefore, SGs can accommodate new energy or electricity products, services, and new energy markets and segments (Kabeyi and Olanrewaju 2022b), since they can accommodate different conversion or generation technologies, sizes, characteristics, and storage options.

4. Better system control

   SGs facilitate increased distribution system infrastructure control by the utility operator through the services and products like DR and self-healing abilities (Jackson 2014). This enhances system resilience and stability to deliver smooth power and services to stakeholders.

5. Integration of coordination

   The SGs create synergy and harmony in the system by coordinating and integrating advanced metering, control, communications, customer service and strategies, leverage technologies and programs to realise across the utility system objectives like reliability, efficiency, safety and economy (Jackson 2014).

6. High system reliability and resilience

   The SGs facilitate optimal asset assets and enhance operational efficiency. This is further enhanced through operational resilience against physical and cyber-attacks on the power system. Therefore, SGs facilitate power quality requirements for twenty-first-century energy requirements.

Therefore, smartening the grid equips it with digital technology and capacity to improve its resiliency, reliability, economic efficiency, energy efficiency, and flexibility of the power system.

2.3. Evolution of the grid

Electrification history began in the nineteenth century in an arrangement where it was generated of specific load application. With the proliferation of power stations at places far from the load centres, electricity transmission and distribution became necessary after Thomas Edison developed the first stable and domestic bulb in 1881, which led to the creation of the first commercial power plant in the USA at Pearl Street Station, in lower Manhattan in the year 1882 that produced 600 kW of direct current. In the UK, the first commercial power station was Pearl Street Station, within the Surrey town of Godalming in 1881, where Thomas Edison helped in the development of the world’s first public electric supply system that supplied city lightening. It is the development of Edison's power station that inspired Nikola Tesla, to develop the first Alternative Current (AC) electric system used to light the World's Columbian Exposition Fair in Chicago in 1893 that marked the beginning of the shift from DC to AC power system at the beginning of the twentieth century. The industrial revolution and technological inventions in power generation and transmission influenced the gradual growth of electricity grids (Ponce-Jara et al. 2017).

Several disasters and challenges influenced the shift to the SG from the traditional grid especially widespread blackouts that hit the USA over many years for example in August 2003, NE blackout affected 50 million with a loss of 62,000 MW power. This influenced the 109th US Congress to approve what came to be called ‘The 2005 Energy Independence and Security Act (EISA)’ which gave tax incentives and subsidies for the integration of renewable energy and energy efficiency technologies in power grids. Additionally, in the 110th US Congress, the SG initiative was initiated as an official policy to modernise the electricity grid of the United States of America and formalised in the 2007 EISA (Ponce-Jara et al. 2017)

The section 1305 of the EISA 2007 made provisions for the National Institute of Standards and Technology (NIST) whose primary responsibility was to coordinate the development of a framework including model standards and protocols for the management of information for realisation of interoperability of SG devices and system which is critical to avoid premature obsolescence of the infrastructure. The NIST proposed three-phase plan to accelerate the development of an initial set of standards to promote the development and deployment of the SG namely the creation of the ‘Framework and Roadmap for Smart Grid Interoperability Standards, release 1.0’, January 2010 as the first phase followed in the second phase by Creation of the Smart Grid Interoperability Panel (SGIP), whose role was to develop additional standards and finally the third phase whose objective was to create a robust framework for conformity and certification of the SG devices and systems (Rathor and Saxena 2020).

The literature does not state any specific start of SG. However, the concept started to evolve with the beginning of distribution systems of electrical networks. Distribution systems needed facilities and capabilities like control, monitoring, pricing, as well as transmission and distribution services. The SG implementation is however associated with the installation of smart meter. As early as the 1970s and 1980s, smart meters were used to send data and information to the grid from consumers. A very important and fundamental need for SGs today is the reliability and efficiency of power transmission and distribution. The desire today is that grids and network systems should not be a barrier or limit to transmission and distribution and should promote the generation and evacuation of clean and sustainable energy to minimise greenhouse gas emissions and hence the carbon footprint of grid electricity (Majeed Butt, Zulqarnain, and Majeed Butt 2021).

Today, SG technology remains an evolving technology resulting from the development in automation, information technology, system control, and IoT. Real-time monitoring and control of power flow from power plants to end users are realised on a real-time basis with the use of SGs (Kiran and Rao 2018). The grid is made smart by the integration of blockchain technology and the traditional electric grid. The blockchain technology facilitates the decentralisation of the grid network operations making central authority in grid control, distribution, and management of the electricity system unnecessary. Transactions and operations on the grid network are stored on the public ledgers of a blockchain. SG technology facilitates buying and selling energy across the network through a computer program by validation and verification of pre-determined transaction clauses. This implies that blockchain technology enables real-time energy markets and the preservation of identity transactions at lower costs (Aggarwal and Kumar 2021).

The NIST first developed a conceptual model for the SG that sets in motion research and development of SG technology. The NIST model has seven domains of the SG namely bulk generations, distribution, transmissions, markets, consumers, operations, and power system service providers. The stakeholders of SGs interact in a two-way direction by using both wired and wireless communication protocols. The communication protocols include the use of Zigbee, WiFi, Homeplug, power line carrier, GPRS, WiMax, LET, Lease line, and Fibres. Many software packages were also developed to accommodate the new grid operation, management, and maintenance like distribution management system (DMS), outage management system, geographic information systems (GIS), customer information systems (CIS), and supervisory control and data acquisition system (SCADA) (Kumar 2022).

2.4. The global smartening and standards for the electricity grids

The global transformation of the power grid is still a work in progress with a few countries already implementing it while many others are still using the traditional grid. Further development in technology and adoption is hinged upon the activities addressing the technical, business, and institutional challenges to the development of the SGs. Smartening can be initiated at various levels like city level, regional, country, national level, continental, or on global scale. All types of electricity systems can be upgraded or improved or optimised but first is to identify key drivers that motivate investment or transformation (Kappagantu, Daniel, and Suresh 2016; UNECE 2016).

2.4.1. Standards in SG industry

Each specialty industry has experts who discuss, develop, and update standards. They are called standard development organisations (SDOs) also called standards-setting organisations (UNECE 2016). The SGs industry has over 25 such organisations. They include National Institute of Standards and Technology (NIST), International Electrotechnical Commission (IEC), National Electrical Manufacturers Association (NEMA), International Telecommunication Union (ITU), IEEE Power & Energy Society (PES), Institute of Electrical and Electronics Engineers (IEEE), IEC SG Standardisation, Internet Engineering Task Force (IETF), International Organisation for Standardisation (ISO), North American Energy Standards Board (NAESB), Society of Automotive Engineers (SAE) (UNECE 2016).

The complex nature of SGs in terms of the number and scale of the systems and devices used, calls for high level of interoperability between the systems for successful implementation. Therefore, research is needed in interoperability issues to increase innovation in grid modernisation efforts where SGIP is an example of institutions engaged in this area of research. SGIP involves over 20 industry segments in smart technologies and deployment and carries out research to catalogue or develop standards and case studies for the deployment of technology and give expert advice about testing and certification (UNECE 2016).

Another area with a lot of interest for research and development is different domains of security for SGs. They include Privacy-preserving smart metering with multiple data consumers, Ortho code privacy mechanism in SG using ring communication architecture and Security Threat Model. Research in the area of security is important because cyber security is one of the greatest barriers for the implementation of SG technology (Majeed Butt, Zulqarnain, and Majeed Butt 2021).

2.4.2. Institutional capacity and sustainability of SGs

Several countries and organisations have initiated joint projects and programs to explore means of promoting the SG industry leading to the formation of several public–private sector partnerships (UNECE 2016). The significance of SGs has led to the creation of several regional and international institutions whose objectives are to promote the development of SGs. Several organisations globally are doing wonderful work in various areas of SG development by offering technical and policy advice inputs. Some organisations specifically handle SGs but some also address SGs as a subset of a wider range of activities (UNECE 2016). The various institutions and their functions are summarised in Table 1.

Table 1. Institutions in SG Industry (UNECE 2016).

	Name	Acronym	Geographical Coverage	Specialty	Sector	Role
1	International Smart Grid Action Network	ISGAN	Global coverage with 25 active member countries	Exclusive SG mandate	Government	Technology and policy
2	Global Smart Grid Federation	GSGF	Global with 18 members	Exclusive SG mandate	Private Sector	Technology and policy
3	European Distribution System Operators’ Association for Smart Grids	EDSO for SGs	European with 30 Distribution System Operators (DSO) members	Exclusive SG mandate	Utility	Policy
4	Reliable and Sustainable Power Grids	GO-15	17 Global Power Grid Operators	Electricity system and technology organisations with SG mandates	Utility	Policy
5	Union of the Electricity Industry	EURELECTRIC	30 European electricity associations	Electricity system and technology organisations with SG mandates	Utility and Industry association	Policy
6	Twenty-first Century Power Partnership	21 CPP	8 member countries + private sector	Electricity system and technology organisations with SG mandates	Research institute and government	Technology and Policy
7	Global Sustainable Electricity Partnership	GSEP	12 of the world’s largest electricity companies	Electricity system and technology organisations with SG mandates	Utility	Policy and project deployment
8	The Institute of Electrical and Electronics Engineers	IEEE	395,000 members in 160 countries	Electricity system and technology organisations with SG mandates	Engineering	Research, Policy, and Standards

Table 1 shows various organisations and partnerships engaging in research, technology, and policy issues necessary for the promotion of SG technology globally. This is evidence of the global commitment to the development of SGs by the establishment of a strong institutional framework.

2.4.3. Technology distribution and use for SGs

SG technologies are broad and cover many systems and applications today, both as developed or developing technologies. They include smart meters, SCADA and FACTS, PMU, V2G among others. The available SG technologies may be specific to electricity systems, while others are used in other energy systems and applications. The technologies used in SG implementation may be significantly common information and communication technologies applied elsewhere in other systems (Ramanath 2023).

The transmission system which generally accounts for about 10% of the network length by connecting a few larger large customers to power plants and interconnecting regional electricity systems is by design and operation smarter than the distribution network because of its responsibility to supply reliable power to the entire power system which leads to higher demand for system reliability and hence more degree of automation, monitoring, and control. This calls for adequate deployment of system management technologies for more reliability and efficiency (Ramanath 2023; UNECE 2016).

The distribution networks on the other hand account for about 90% of total electricity network length having most of the power consumers smaller scale distributed generation (DG) that is connected to distribution networks. The distribution networks are designed to deliver high levels of reliability and resilience under the worst-case scenarios that are referred to as ‘fit and forge’ which often led to high levels of reliability but may lead to system over-design or may not be fit for increased demand like high penetrations of electric vehicle charging infrastructure in urban centres) or higher uptake of VREs of electricity. SGs can be applied to optimise the distribution system by provision of power systems monitoring and managing power flows from generation to demand. For optimum design, it is critically important to have the right breadth of technologies for the entire electricity system (UNECE 2016).

2.4.4. Telecommunications technology for SGs

The operation of SGs relies upon the availability of a telecommunications network to interconnect the generation sources, network sensors, or smart meters into the power utility operational processes. Before the development of the SG, telecommunication was only required to deliver connectivity for back-office systems and for the remote monitoring of high-voltage interconnections with the transmission grid and hence there was no need for dynamic monitoring and control as power moved only in one direction from few centralised power plants. It was therefore possible to manage the distribution networks based on predictive grid performance profiles generated over years of operation experience (UNECE 2016).

The development of an SG is built on the foundation of communications networks that can deliver centralised real-time monitoring and control, across the entire power distribution domain. Advances in telecommunications technology now offer a wide range of solutions needed to deliver the SG. These, however, require supportive policy and standards deliver tested and approved products and systems designs for adoption by Government and utility purchasing authorities. Rapid increase in the points of interconnection with other information networks because of SG development creates potential threats of cyber-attack power management systems hence the need for policy and standards bodies to ensure that cyber security is mandated as a central and essential element of any SG design and operation (UNECE 2016). Therefore, advanced telecommunication infrastructure offers threats and opportunities to the power sector.

2.4.5. Data and information in SGs

Data and its applications in the energy sector is one of the main elements of the Energy Internet, with promising and crucial challenges to address particularly with respect to the integration of renewable energy to the grid. Very important for an SG system is the ability to collect data and to properly apply it to make better and accurate judgement and decision-making (Mostafa, Ramadan, and Elfarouk 2022). The SG is embedded with an information layer enabling two-way communication between the local actuators and central controllers and logistic units to digitally respond to situations of physical elements or changing demand and supply of electricity (Zhang, Huang, and Bompard 2018). Data analytics plays an important role in SG systems. The information layer added to the conventional grid assist in data collection, data storage, and analysis assisted by widely installed smart meters and sensors (Abrahamsen, Ai, and Cheffena 2021; Zhang, Huang, and Bompard 2018).

SGs use Information and communication technology (ICT) for the operation, monitoring and control of data to realise high reliability, economics, efficiency, and sustainability (Umar, Singh, and Sanober 2016). In SGs, automated and distributed energy delivered relies on a two-way flow of electric power as well as a two-way flow of information. The system facilitates an instantaneous balance of electricity supply and demand in SG devices made possible by the incorporation of distributed computing and communications. This architecture enables real-time information exchange (Bari et al. 2014). The communication in SG communications is based on both wireless and wired network technologies. Networks can be classified based on functionality within the SG. The classes include home area network (HAN), access network, neighbourhood area network, backhaul network, and external networks. The SG networks connect home appliances, switches, smart meters, transformers, reclosers, relays, capacitors banks, integrated electronic devices (IEDs), relays, actuators, access points, concentrators, scanners, printers, routers, cameras, cameras, field testing devices, computers, and other devices (Kumar 2022).

The various sensors on the SG system gather data for use by different algorithms in applications like forecasting and utilisation by the smart energy management systems (EMSs). The data is gathered from the system meters and data related to the weather and environment. The data for the smart system should have desirable characteristics like the ‘4Vs’ (volume, velocity, variety, and value) and ‘3Es’ (energy, exchange, and empathy).

There are several challenges that are related to data even though there are algorithms and models developed for big data analysis with respect Information technology (IT), infrastructure, data collection methods and governance, information and data processing and analysis, data integration and sharing and data security and privacy (Majeed Butt, Zulqarnain, and Majeed Butt 2021). Figure 1 shows the relational data flow between parts and sections of the SG architecture.

Figure 1. Data flow in SGs.

From Figure 1, it is noted that the SG system has different levels and stages of data handling, i.e. data acquisition, data processing, and output. The input information to the SG system includes information on weather, financial data, utility specific information through the GIS, SCADA, EMS, and OMS. The output data is used in forms like control room displays, desktop displays, geospatial displays, and mobile device data outputs.

There are two types of communications for SGs. They are the HAN and Wide Area Network (WAN). HAN connects the in-house smart devices to the smart meters using Zigbee, wired or wireless Ethernet, or wireless Bluetooth. On the other hand, the WAN is bigger and joins smart meters, companies, and energy application systems. The technology used includes WiMAX, 3G/GSM/LTE, or fibre optics. It is the role of the smart meter to connect in-house devices and the exterior parties for information and communication exchange (Umar, Singh, and Sanober 2016).

2.5. SG hardware and software

The main components used to smarten or convert a traditional grid to an SG are the two-way communicable sensors used for monitoring and control electricity flows on real-time basis, the information technology systems whose work is to process data captured and give commands and alerts in response. Presented as a human body analogy, the SG system is like a body provided with the brain which receives and processes data and communicates output and also receives and sends signals via the nervous system which conveys the signal to muscles that deliver the energy for action (Kiran and Rao 2018). Figure 2 shows the main elements of an SG architecture.

Figure 2. Elements and stakeholders of SGs.

Figure 2 shows the main elements that make up the SG system. They include central and decentralised stations, renewable and nonrenewable energy power plants, grid automation infrastructure, intelligent substations, smart switches and distribution automation, car parks with electric charging stations, energy storage facilities, smart buildings, end-user energy storage, among others. The elements are spread over the generation, transmission and distribution and end user or demand side sections of the power grid system. These facilities enable SGs to create new opportunities and capabilities. By application of digital technologies and IoT, the SGs intelligently manage continuous grid parameters. The application of intelligence facilitates enhanced grid reliability, flexibility, cost-efficiency, and system safety and also enables consumers to control both consumption and generation (Kumaran, Singaravelu, and Vivekananda 2013).

2.5.1. SCADA

The SCADA is an Extra High Voltage (EHV) transmission network (110 kV and above) usually smart or intelligent and equipped with automation and real-time communication systems. The SCADA and the EMS monitor and control power flows in real time at dispatch centres or load control (LC) centres of EHV systems. A dedicated communication system between the control center, power plants and the EHV substations facilitates the operation of SCADA/EMS. It is from the control centres that operators can control power generation and load at system substations (Kabeyi and Olanrewaju 2022v; Kiran and Rao 2018).

SCADA allows a user to gather data from distant fields and send control commands to same distant fields. It provides a visual management interface for the power system operators for remote control and configuration of the power network. Although some utilities developed many different control systems for grid management, most of the utilities rely on SCADA systems to supervise their power infrastructure (Umar, Singh, and Sanober 2016). The SCADA operates by collecting information related to grid operation from various sensors located at various points and send data to the master computer for real-time analysis (Kiran and Rao 2018).

2.5.2. The energy management system

The evolution of the EMS started in the 1960s and was termed a control center, and later was referred to as an energy control center (ECC) during the 1970s. It was renamed supervisory control and data acquisition-EMS (SCADA-EMS) when the SCADA system which works based on advanced computers appeared in the 1990s. This later evolved into a real-time control system known as EMS. The EMS incorporates various control techniques like LC, demand–supply management (DSM), and DMS. The role of the EMS is to allocate energy to e customers optimally while integrating sustainable power sources without compromising power system security, reliability, and safety. The EMS monitors, supervises, optimises, and controls the generation, transmission, distribution, and consumption of energy to create a balance between demand and supply efficiently and cost-effectively while maintaining the operational constraints and uncertainties on EMS architecture including variability and intermittence of renewable energy sources, price of electricity and customer behaviours (Kabeyi 2020c; Rathor and Saxena 2020).

The EMS can work for real-time SCADA applications, electricity dispatch, generation scheduling, system control, and energy accounting and energy transmission security management. Today and into the future, EMSs are becoming more and more complicated, because of the growing use of plug-in electric vehicle (PEV) and VREs, energy storage systems (ESS), growing energy demand in buildings and industry among others. The functionalities of the EMS have further been enhanced by advances in the IoT and machine learning and their adoption by the energy sector (Rathor and Saxena 2020).

The growing integration of highly varying or fluctuating DG systems particularly PVs, wind t, electric vehicles, and ESSs is a serious threat to the stability of power systems because balancing power ratio between supply and demand becomes difficult and complicated. Excess or shortage in the generation or consumption electricity causes perturbations to the grid and creates severe issues like voltage drop or voltage rise and related blackouts. Under such threats, the EMS is adopted to ensure efficient balancing between power supply and consumption demand to reduce the peak loads when undesirable (Meliani et al. 2021; Sahu 2016).

The energy management is divided into two main categories, namely the supplier side like electric utility, where some generators may be switched ON or OFF or follow the fluctuation of demand (demand following). The second category is the consumer side, or demand-side management, where the consumers manage their energy consumption to match the supply from the power generation side. On the consumer side, the main goal of the EMS is to reduce operation cost as well as consumption, reduce energy losses and enhance power system reliability. The development of sophisticated algorithms and models will improve the EMSs (Meliani et al. 2021; Sahu 2016).

EMS is used by grid operators as a tool for monitoring, controlling and optimisation of power generation and transmission systems. The main functions of the EMS include real-time network analysis and contingency analysis, study power flow, power factor, and security enhancement. The EMS enables real-time functions which the plant operator to monitor, analyse, and control power generation functions on a real-time basis. It also enables automatic generation control. The EMS also sets economic dispatch and directs the dispatcher to set economic base point for the generator units selected.

Other functions performed by the EMS of the SGs include monitoring the reserve and establishing the sinning reserve, regulating reserve, and operating reserve levels. The EMS also computes the production costs, forecasts load, and scheduled transactions. The SGs advanced functionalities include grid reliability enhancement, increasing grid capacity, advanced contingency awareness operations, and cost management. Besides the technical capacity and requirements, an SG should meet the regulatory requirements (Kiran and Rao 2018). Therefore, overall EMS in an SG enhances reliability, increases efficiency, and compliance with standards.

Various bioinspired approaches are used for smart EMSs strategies with commonly used systems being the Home Energy Management Systems (HEMS) and Building Energy Management Systems (BEMS). There are two groups of bioinspired bio-inspired computing, i.e. evolutionary computing and swarm intelligence computing (Beaudin and Zareipour 2015). Evolutionary computing involves the incremental development of living organisms in reaction to environmental conditions, while swarm intelligence focuses on agents’ collective and social behaviours in the energy system. These algorithms assist in the design, planning, and control of smart EMSs for homes, buildings, and SGs (Bayram and Ustun 2017). The main objective of the EMS in an SG system is to minimise energy consumption by device scheduling within specified time horizons (Nguyen et al. 2020). The main functions of the EMS are summarised in Figure 3.

Figure 3. Functional view of energy management system in an SG.

From Figure 3, it is noted that the EMS in an SG has three main functions, namely demand side management, utility side management, and generation planning and management.

The planning and execution of grid activities must be done using interoperability. The NIST established the SGIP whose responsibility was to develop and maintain the standards for SGs and related components necessary for efficient operation. SGIP also provides a platform for all the stakeholders of power grid like the markets, customers, service providers, the power system, generation, transmission, and distribution network to cooperate and work together. Grids and end users must play their roles effectively for the implementation of energy management. The EMS is made more realistic for SGs due to technologies like communication, advanced metering infrastructure (AMI) and cyber security which facilitate self-decision capabilities for the power grid (Majeed Butt, Zulqarnain, and Majeed Butt 2021)

2.5.3. Smart meters and advanced metering infrastructure (AMI)

Smart metering can revolutionise access and control of energy consumption. A meter is said to be smart if it has capabilities like real-time monitoring; local and remote data accessibility; remote meter controllability, energy cut off; interaction with other meters like gas meters, water meters; quality monitoring of power and device self-analysis; and interaction with the IoTs) (Lo Cascio et al. 2021). In studies on ICT-linked energy saving by Bastida et al. (2019), Lo Cascio et al. (2021), it was estimated that between 0.23% and 3.3% of the European CO₂ reduction target to reduce global warming to the 1.5°C minimal realistic warming goal by 2100 can be attributed to the use of ICT in the energy sector. Smart meters make it possible to read in real-time rates and pricing policies, which facilitate DR and demand-side management programs. Hence smart meters enable realisation of energy efficiency, increase system reliability, and yield significant economic savings to both customers and utilities (Bastida et al. 2019; Lo Cascio et al. 2021). Smart meters constitute an important element of the smart metering system.

AMI is also called Smart Metering and comprises equipment or devices like Smart Meters, Data Concentrator Units (DCUs) also referred to as gateways, routers or access points, Meter Data Management System (MDMS), HAN, Head End System (HES), communicating over bi-directional WAN, Neighbourhood Area Network (NAN) or Field Area Network (FAN), and Multiple smart meters used to connect to the DCU/gateway/router/access point to send aggregated data to the HES. Smart meters can communicate with the HES directly via appropriate WAN technologies like the GPRS sim cards placed in the smart meters to send data to HES on the servers in the control room (Kiran and Rao 2018).

The role of the MDMS is to collect data from the HES, process and share with the billing system as well as other IT applications. The HAN can incorporate common appliances like fridges, television sets, radios, heaters, dryers, washing machines, air conditioners, water heaters among others. It is the inclusion of a two-way machine-to-machine (M2M) communication module in a meter as well as a remotely operated connect and disconnect switch that makes a meter smart. The smart meter is always at the heart of the AMI. The smart meter electronically records electricity consumption normally on hourly intervals or less and communicates with the utility on regular basis for monitoring and billing. Smart meters facilitate a two-way communication between computer systems/computers at the utility control centres and the meter (Kappagantu, Daniel, and Suresh 2016). They are equipped with real-time or near real-time sensors, power quality monitoring features and outage notification capabilities (Kiran and Rao 2018). This capability helps in cutting down outages through quick response in case power failure or intermittent in supply where supply comes from variable renewables or outages caused by extraneous factors to the conventional power supply sources.

Smart meters are the backbone in the development of SGs. Smart meters make billing free from manual intervention unlike the traditional billing system where an individual must move from house to house to note down the readings from energy meters normally once a month. With smart meters, billing can be done for multiple consumers any time desired (Kappagantu, Daniel, and Suresh 2016).

2.5.4. Wide area monitoring system (WAMS)

An SG deploys Phasor Measurement Units (PMUs) which facilitate faster and more accurate measurement of the grid equipment. For real-time wide-area monitoring applications, the latency requirements are high in the range of 100 ms to 5 s. This requires a fast communication system to handle these huge amounts of data from the PMUs. SGs are meant to exploit high data throughput measured in real-time. The main difference in functionalities between PMUs and SCADA is that SCADA data is collected in 1–5 s, but PMU data is captured in milliseconds. Additionally, SCADA data does not have timestamps, while PMU data is accurately time stamped. Operationally SCADA works like an X-Ray, but PMU Data is like an MRI scan of the electricity grid (Kiran and Rao 2018).

2.5.5. Distribution automation (DA)

Distributed Automation (DA) refers to the different computerised control strategies meant to upgrade implementation of energy dispersion by enabling specific gadgets to detect operational states of surrounding lattice then influence necessary changes in line with enhanced general energy to streamline operations. With no SG configuration, lattice must physically recognise and break down the energy system physically and either remotely enact gadgets or dispatch an expert to intervene (Kiran and Rao 2018). The distribution automation related sensors and interchanges can recognise faulty gadgets and enable the power to utility to take early action. It is through distribution automation that the network is made more proficient and solid. Renewable Energy (RE) is empowered by distribution automation systems by appropriate change of controls to suit fluctuation, control inclining and bi-directional power streams (Henderson, Novosel, and Crow 2017).

2.5.6. Substation automation

Through automation of substations, it is possible for the utility company to remotely monitor, control, coordinate and operate power distribution components at substations. This will cut down interruptions and downtime caused by equipment failures, strikes from lightning, accidents and natural catastrophes, surges or power disturbances and substation outages. The equipment or components of substations are made digital (or numeric) with related communication systems to facilitate remote operation (Kiran and Rao 2018).

2.6. Block chain technology

Block chain refers to a distributed network, which maintains an immutable database proposed by Satoshi Nakamoto and first implemented in the bitcoin as a technology that enables a community to maintain trust (Agung and Handayani 2022; Guo, Wan, and Cheng 2022). The block chain technology has potential to transform applications through creation of trust and facilitate decentralisation. The technology was considered as a cryptocurrency at the beginning of its application in digital currency although it was just the backbone cryptocurrencies. In a decentralised network, the block chain is distributed ledger for the transactions taking place. Although many researchers were initially sceptical about the block chain technology, it is the popularity of Bitcoin that changed the negative perception (Guo, Wan, and Cheng 2022; Skopik and Smith 2015). The various applications of the block Chain technology is demonstrated in Figure 4.

short-legendFigure 4.

From Figure 4, it is noted that the block chain technology has wide applications in fields like securities which include debt, equity, crowd funding, and derivatives; smart contracts like wagers, escrow, and digital rights; record keeping in health care, voting, intellectual property, title records etc.; and digital currency applications like microfinance, global payments, and ecommerce.

The block chain consists of blocks of transactions that are linked together in a chain. The client/server architecture is applied in the traditional client/server systems and has various administrators who oversee the systems. The block chain as a distributed, decentralised peer-to-peer (P2P) network has every network participant with ability to control the network. The block chain network has connected computers or nodes, while the blocks in the chain need the network’s approval to be changed. The nodes in the network have a copy of digital ledger (Skopik and Smith 2015) and the blocks are ordered in a time-sequential manner, with a hash function being used to secure and link them. Unlike in bitcoin where transactions change of ownership of the money, the transactions in SG block chains are of electricity. A hash function refers to a mathematical one-way function with a fixed output, for ant given input with a significant change in output being realised for any slight change in the input (Agung and Handayani 2022)

Block chain refers to a secure, transparent, and decentralised, means of recording and sharing data, without relying on third-parties or intermediaries. An example of a block chain application is the digital currency, Bitcoin. Other applications of block chain technology include making supply chains traceable, combating voter fraud, and securing sensitive data like medical data (McGinnis 2020). In SGs the block chain technology is made up of distributed ICT that supports decentralised structure of local energy markets and facilitate direct interaction between users (Tsao and Vu 2021). In a block chain-based local energy market prosumers who are both consumers and producers in a system can trade electricity without intermediaries. The market place is represented by a smart contract which accepts orders from all participants of a block chain and performs a merit-order mechanism for efficient allocation (Tsao and Vu 2021).

SGs can integrate the digital sensing and communication devices through the block chain technology which enable racking of energy consumption on real-time basis, control equipment use, and facilitate a two-way communication utilities and power consumers and devices. The development of SGs shifted attention to EMS for smart homes like HEMS, BEMS among others (Rathor and Saxena 2020). Therefore SGs have created extra opportunities of optimal power production and use through various EMSs (Nguyen et al. 2020; Rathor and Saxena 2020).

The community or stakeholders in the SG can maintain transactions in the system by integration of block chain into the SG. SG transactions are done with smart contracts with transactions history being stored in the block chain and duplicated to all full nodes. The block chain restricts change, which ensures that a smart contract between a generator and a consumer is executed always providing certainty that a power producer will always deliver the electricity. The provided by the block chain also provides traceability needed for audit or solving a transaction dispute (Agung and Handayani 2022). The main challenges facing block chain technology is expertise and. high initial cost of the infrastructure costs. Concerns over privacy and security the deployment of block chain technology. Other issues with block chain technology are scalability and legal requirements in some countries (Skopik and Smith 2015).

2.7. Communication in smart grids

Communication systems provide a means to exchange data and monitor various elements for effective control and protection in SGs. The communication system enables the control signals to reach components in a centrally controlled MG. For decentralised systems, the communication network enables components to talk with other components, and make on the operation, and realise the system predefined objectives. Communications in SGs facilitate rapid fault identification and clearing (Parhizi et al. 2015). It is necessary to use the communications system to update the protection of MGs because of variable nature of grid conditions. Because of variable MG operating conditions the meshed topology of grids communications is often used for updating the communication settings. The traditional communication-less protection schemes do not apply in a meshed MG in which a fault at one location may not be distinguished from another (Parhizi et al. 2015; Sandelic et al. 2022).

A power system has got three key domains, namely: power generation, transmission, and distribution. The main elements of a conventional power generation scheme are a synchronous generator often with a 3-phase electrical energy produced by prime like steam, gas, hydro turbines. Voltage is stepped up and down in the transmission and distribution substations. Distributed energy systems like wind, solar, marine etc. are interfaced with power electronic devices to meet load requirements while customer premises consist of loads which are modelled based on their active and reactive power requirements (Panda and Das 2021).

The SG has a communication layer whose primary purpose is to interoperate between manual control and multiple automatic controllers, sensors, and actuators in the physical layer of the grid. An SG needs a scalable, secure, and robust communication infrastructure for design and secure operation. The sending, control and communication standards of electricity systems ought to be robust enough to meet the latency and overcome the bandwidth challenges for communication systems. Major communication technologies include IEEE specified Zigbee, WiMAX and wireless LAN technologies, GSM 3G/4G cellular and DASH7. These communication technologies are used in SG domains station substation automation, home area automation, vehicle to grid communication and metering infrastructure. A fundamental research challenge is standardisation and interoperability of the communication standards for SGs (Panda and Das 2021). The most common standard of power systems communication in power systems and SGs is the power line communication (PLC) which is commonly utilised in high, medium and low voltage power networks. The presence of noise and vibration and interference in the network makes reliable operation of wireless sensor networks very challenging in the industry 4.0 paradigm, used in the SG context. Therefore there is need to have a robust communication network for successful operation of wireless sensor networks (WSNs) in SGs. Solutions include use of a dynamic clustering which is based on optimised protocol which improves the system’s reliability by reducing the excessive packet retransmitted in the communication networks of SG (Panda and Das 2021). Figure 5 shows the structure of the communication layer of the SG.

Figure 5. The communication layers.

Figure 5 shows the communication layer where grey illustrates the communication layer, blue sit the component layer, red is information layer, green represents the functional layer while brown represents the business layer.

In order to mitigate the uncertainty and noise in networked systems, it is necessary to have a control strategy that ensures optimal system performance (Panda and Das 2021). It is the role of the information layer to facilitate data exchange and storage for SG protection and control applications. SGs need revolutionary ICT technologies to achieve robustness and reliability under a highly dynamic network of many players. Automation architecture is provided by standards - IEC 61850 and IEC 61499 which support multi-agent intelligence and DA simulation. Software like SimPowerSystems in Matlab can be used for validation of custom-designed user datagram protocol (UDP) socket. The optimal efficiency of the multi-agent network, is critical to achieve a robust operability between them under various operational network topologies . Market algorithms are used to maintain a balance between supply and demand which in some typical applications use PowerMatcher software (Panda and Das 2021).

To ensure end-user privacy and security, the information exchange in power systems should not be accessed through local gateways. Data privacy is preserved through end-to-end encryption whose limitation is that it increases the data size causing unacceptable communication overhead. A typology in which data aggregation is performed at multiple levels based on hierarchy and frequency has been indicated to be helpful for load allocation and power generation administration applications. Security architecture can be defined by the application of multiple gateways at customer premises which provide communication and cryptographic abilities amongst themselves and external entities. This enables privacy preservation in the network. Homomorphic encryption can be used in smart meters for DR schemes which secure users’ session using adaptive key evolution (Panda and Das 2021).

2.8. The grid in electricity generation and distribution/supply

An SG is made up of transmission lines, substations, transformers, and other devices using digital and advanced technology for monitoring, control, and management of power generation transmissions and distribution from power stations to customers or end users. electricity from all power stations in a manner that copes with load variation. They use information technology to deliver electricity in a planned, efficient, reliable, and secure manner by enabling two-way communication and two-way energy and information flow. Unlike the traditional grid, they have the ability to self-monitor, self-heal, or regain and can facilitate pervasive control and enhanced interoperability (International Energy Agency; Kumaran, Singaravelu, and Vivekananda 2013; US Department of Energy 2018). The SG system can be integrated from different sources of renewable energy, such as photovoltaic panels, wind farms (Belkaid et al. 2019) and also integrates DERs to optimise electricity production and delivery (Kumaran, Singaravelu, and Vivekananda 2013).

To achieve their objectives, SGs are equipped with computer technology and programs that enable communication, automation and connectivity of components and functionalities of electricity generation and supply between power plants and consumers (Defranza 2020). The main working components of an SG are smart meters, computer systems, system controls, smart appliances, EMSs, and energy sources or power plants and end users appliances (US Department of Energy 2018). By use of a phasor measuring unit (ppm), current and voltage is measured severally per second and can give the location as well as a smart shot of the power system which enables dynamic visibility into the system. SG involves simultaneous modernisation of the transmission and distribution grids (Vijayapriya and Kothari 2011).

To function properly, SGs need electronic power control and distribution. Figure 6 illustrates an SG with its basic components.

Figure 6. Illustration of an SG (Prasad 2014).

Figure 6 is an illustration of a typical SG showing various elements namely transmission lines, power plants, renewable energy sources, i.e. wind, solar, consumers like factories, transmission grid, distribution grid with city and rural networks, substations, nonrenewable sources like coal, nuclear with all elements interconnected.

SGs improve both efficiency and of the traditional grid and create opportunities for enhanced uptake of variable renewables by use of computers and communication technology for advanced data processing, analysis, and control. Besides increase accommodation of VREs, the technology also supports variable loads like charging electric vehicles and support for the V2G technology (Prasad 2014). Therefore SGs will coordinate the needs of power plants, consumers, and other stakeholders to ensure efficiency, minimum cost, and environmental impact while ensuring maximum system reliability, stability, and resilience (International Energy Agency; Defranza 2020). These are the key requirements for sustainability.

3. SG products and services

The traditional grids simply transmit power generated at central power stations with voltage transformers that increase and reduce voltage to supply electric power to consumers. Unlike the traditional grid, SGs, perform the functions of the traditional grid and added the ability to remotely monitor all activities or faster and better responses and performance of the power grid (Elservier 2015; Kabeyi and Olanrewaju 2022d). Globally, SG technology can address the energy sustainability and transformation challenges like over reliance on fossil fuels, large gap between demand and supply, and limited access to renewable energy resources. If well addressed, they will enable a smooth transition to smart energy systems (Elservier 2015). The specific products and services or SGs are as follows.

3.1. NET metering

Integration of renewable energy sources with SGs means that power can flow in either direction. Smart meters can meter both flows to compute the net energy at the consumer premises. Smart meters can measure three important components of energy, i.e. kWh, kVArh, and kVAh. The smart meters are also equipped with communication facilities for two-way exchange with the control centre, to transfer data and receive control commands (Kappagantu, Daniel, and Suresh 2016). Net kWh curve represents the difference between import kWh curve and export kWh curve, where the positive indicates that the consumer imported more than he supplied to the grid, while the negative portion shows that the consumer injected more power into the grid than he imported (Kabeyi and Olanrewaju 2022g).

3.2. Time of use (TOU) metering

This metering or billing system is based on the time that power is consumed with higher charges during the peak and lower charges during off-peak to facilitate better load management (Kappagantu, Daniel, and Suresh 2016). The TOU tariff helps shift load from the peak load time to off-peak period which has the potential to increase the performance of the system by reducing maximum flow through the system. as maximum power flow in the network would be reduced and reduce pressure on power generation. which often use fossil fuels sources for peak supply.

3.3. Peak load shaving

Peak load is an important factor for power grids because it only for a small percentage time duration in a day and requires extra generation capacity which is economically feasible and is an inefficient use of generation capacity required for just limited time (Uddin et al. 2018). Peak load shaving refers to the shifting loads from peak periods to off-peak periods. By use of SGs, it is possible to shift various demands to operate within minimum ranges. SG facilities create flexibility and demand shifting leading to load management, peak shaving and energy saving through moving loads from peak period to off-peak periods. The peak load benefits both consumers and utility operators (Kappagantu, Daniel, and Suresh 2016).

The growth in peak load increases the chance of power failure and increases the marginal cost of electricity supply hence the increasing need to reduce peal demand. Peak demand is often met by gas turbine and diesel engine power plants which are expensive power and polluting from greenhouse gas emissions. Therefore, peak load shaving has economic and environmental benefits. And is achieved mainly by three different strategies namely.

1. Integration of ESS

2. Integration of Electric Vehicle (EV) to grid

3. Demand Side Management (DSM).

3.4. Billing efficiency with smart meters

A smart meter is an electronic device used for measuring natural gas, water, or heating. The smart meter is equipped with real-time or near real-time sensors, outage notification, and ability to monitor power quality. Smart meters are similar in many respects to AMI meters. As opposed to interval and time-of-use meters smart meters have automatic reading ability (Federal Regulation Commission 2008, National Institutte of Standards and Technology (NIST) 2014).

A smart meter records energy information like electricity consumption, voltage levels, electric current, and power factor and communicates to the consumer thus ensuring clarity on consumption behaviour. They also communicate with the utility company for system monitoring and billing. The smart meters facilitate a two enable two-way communication between the central system and the meter (National Institutte of Standards and Technology (NIST) 2014).

The smart meter differs from AMR due to its ability to effect two-way communication between the meter and the supplier. The communication facility in smart meters is achieved through wireless or fixed wired connections. Common wireless options for smart meters are cellular communications, Wi-Fi (readily available), wireless ad hoc networks over Wi-Fi, Wi-SUN (Smart Utility Networks, wireless mesh networks, low power long-range wireless (LoRa), Wize (high radio penetration rate, open, using the frequency 169 MHz), and ZigBee (low power, low data rate wireless) (Federal Regulation Commission 2008). SGs make use of smart meters as the backbone in the development of SGs. have made billing free from manual operation as opposed to the traditional billing cycle usually done once a month by many utilities. With SGs billing can be done over shorter cycles like 30 min and in some cases, prepaid services are available. Accuracy in metering is also significantly improved by smart metering and in some up to 655 improvement has been achieved by conversion from manual to smart meters which reduces commercial losses (Kappagantu, Daniel, and Suresh 2016).

3.5. Power quality control

The integration of renewable resources via power electronic devices into the grid is one achievement of SGs. Variable renewables introduce harmonics into the power system which can deteriorate the quality of power. SGs use automatic power factor correction (APFC) devices and active filters to improve the power factor and power quality. The Installed APFC devices are equipped with modern communication functions for regular reporting to the utility control center (Kappagantu, Daniel, and Suresh 2016).

3.6. Outage management

The SG has an Outage management system (OMS) which can enhance the reliability of the power systems by application of the grid smartness for operational benefits like power restoration, reliable and cost-effective services. This is technically achieved by incorporating AMI, DA, ICT, and other smart devices in the SG power system (Kappagantu, Daniel, and Suresh 2016). Outage management can be realised by distribution transformer monitoring system (DTMS) and in addition fault passage indicators (FPIs). In some typical installations, DTMS systems are equipped with oil sensors, palm sensors, CT, and PT. The DTMS can measure all phase current loadings, transformer oil levels, and temperatures of DT (Kappagantu, Daniel, and Suresh 2016).

3.7. Loss detection

The use of smart meters to collect, compute, store, and transfer energy data to control centre occurs at constant intervals of say 30 min. Power losses can be determined by comparing the energy data at different nodes and DT terminals, power. This enables quick measures to restore power to consumers (Kappagantu, Daniel, and Suresh 2016).

3.8. Tamper analysis

Tampering of meters includes deviation from defined limits some fault or malpractice or damage on the metering system. Smart meters are designed in a way that they send a signal to the server and information to all parties concerned in the event of tampering in the form of SMS and e-mail and SMS alerts. Examples of t tampering cases include over-current, terminal cover open and flow of current through the earth. Tamper alerts facilitate quick and specific response by authorities from the utility company. Through tampering cases, consumers may be drawing current than the limit, the meter may change locations without prior information or authority, the meter itself may be faulty hence malfunction. Other tempering cases include bypassing the meter and connecting undesirable loads (Kappagantu, Daniel, and Suresh 2016).

3.9. Better reliability

The reliability of a power system depends on customer needs and is measured as the ability to meet customer needs. Therefore, a reliable power system implies having a flawless and errorless system continuously supplying power to consumers. This is achieved in SG by the ability to detect faults and self-healing potential of the system. The limitation of the conventional grids is with regards to the interaction of renewable resources, support of MG and DR. SGs can monitor all information and data and can establish system reliability. It is possible to monitor hybrid generation and management of the grid remotely which improves reliability. SGs make use of technologies like Dynamic Stochastic Optimal Power Flow (DSOPF) which make it possible to estimate and optimise power flow in the system. Therefore SGs can improve system reliability through enhanced metering and communication (Majeed Butt, Zulqarnain, and Majeed Butt 2021).

3.10. Demand side management

Demand side management refers to programs and measures that can be used to influence consumers to balance their consumption and generation capacity of the utility (Uddin et al. 2018). Demand-side management is a direct effect and benefit of SG systems whose key objective is to allow the utilities to manage consumer loads. An important feature of demand-side management is the development of incentives for smart customers to modify their temporal use of power to reduce peak loads. Demand side management is strongly connected to DR models, as programs that seek to shape the demand and supply to achieve an efficient power system. Interconnection of consumers, MGs, electric cars, as well as utility companies can only be made possible using efficient and effective demand-side management (Bari et al. 2014) Demand side management is categorised into two main parts: namely energy efficiency and DR.

3.10.1. Energy efficiency

Energy efficiency refers to the use of less energy economically to provide same or better services to customers (Uddin et al. 2018). Energy efficiency is important as it ensures sustainable use of energy resources by reducing a country's dependence on imported and expensive energy resources and serves to increase awareness of environmental challenges which is a key requirement for sustainable development l (Duzgun and Komurgoz 2014). The use of SG technologies helps in dealing with intermittent power and low power system utilisation efficiency. SG techniques increase the amount of intermittent renewable generation in power system, by increasing the capacity of grid-connected clean energy like solar energy, wind energy and photovoltaic system while at the same time promotes energy saving in power system. Therefore SGs improve the power system efficiency by improving the utilisation efficiency and the power consuming efficiency of the power systems (Hu et al. 2014).

3.10.2. Demand response (DR)

DR refers to the change in electricity consumption using the demand-side resources away from the normal consumption patterns as a result of response to applied changes in electricity price over time or as a result of application of incentive payments that are meant to motivate electricity price reduction meant to avoid the system reliability from being jeopardised (Uddin et al. 2018). DR is the ability of residential, commercial, and industrial sectors to modify energy-consuming models in response to variations (Separi, Sheikholeslami, and Barforoshi 2021). DR plays a very important role in peak shaving to balance generation and consumption. There are various DR techniques that can be adopted to shave peak load e.g. incentive-based direct LC programs through lower pricing or coupons (Uddin et al. 2018).

The two-way communication provided by SGs enables consumers to interact with the grid and other stakeholder which provides an opportunity for a more economical use of grid power and hence higher efficiency and reduced peak time stress by shifting load and self-generation. The demands of side management options focus or rely on adequate communication between utility company and end users, a facility that is provided by SGs. With further evolution, scheduling of consumption by end users will enable the distribution system to schedule resources based on requirement. The system also provides financial incentives by scheduling consumer needs (Majeed Butt, Zulqarnain, and Majeed Butt 2021).

DSM is an important feature of smart power grids that can be defined as a set of techniques applied to modify the electricity consumption pattern by end users. Demand side management methods motivate consumers to optimise energy consumption and reduce energy costs and improve efficiency. The benefit to consumers is to reduce electricity energy bills but energy systems or utilities benefit through demand shifting from peak to non-peak hours. The DSM actions are applied in smart meter management to control the load profile of consumers to realise efficient utilisation of power plants. The SGs overcome support help address challenges of conventional electricity gird through support for new concepts and technologies like renewable energy resources, distributed power generation (DG), smart meters, and energy storage (Nasir 2021)

SG facilities have also led to the development of smart devices which could communicate with the grid and make the consumer or facility more autonomous through effective and efficient use of power or energy resources. Smart appliances can shift the demand for household electricity to off-peak or low-price periods. Which saves on the cost of power for the consumer. Household appliances can also be remotely operated by means of networking protocols like ‘ZigBee’ which provides a solution to have a wireless control. These protocols facilitate communication and coordinate with all the stakeholders in the EMS thus they provide optimal solution to the use (Majeed Butt, Zulqarnain, and Majeed Butt 2021)

The SGs are of significant benefit to the Retail Electricity providers (REPS) who can make us of demand response programs (DRPs). REPS fill the space between wholesale electricity markets and final consumers. REPS use forward contracts and can purchase part of the consumer demand through the pool market. The retail electricity providers face financial risks from factors like volatile loads, price variations, and actions of generating companies with market implications. However, REPS can manage these risks by employing DRPs. For example, reps can propose selling price based on fixed tariffs, time-of-use price, or actual time price during the contract period. Power end users can shield themselves against financial risks by long-term contracts with REPs. Therefore, REPs can apply a blend of methods to control the financial risks from wholesale markets using well-designed DRP (Separi, Sheikholeslami, and Barforoshi 2021).

To implement DR, it is necessary for consumers to have smart meters. DR plans can be exploited by retail electricity providers as an alternative allowed through smart technology to enhance the anticipated benefits of varying demand. SGs provide intelligent technologies in grids and HEMS, for the moderation of financial risks. REPs can also use DG and ESS (ESS) they possess to manage costs and financial risks and these resources can effectively be managed SG systems (Separi, Sheikholeslami, and Barforoshi 2021).

3.11. Decentralised generation

The decentralisation of generation has generated global interest in the development of reliable and sustainable electric power systems as a strategy to use more local renewable and alternative sources of energy. In addition to reducing stress and loss in transmission, it reduces transmission and distribution losses (Bari et al. 2014; Vineetha and Babu 2014). Decentralised generation uses different local energy sources to meet the demand of local electricity demand (Bari et al. 2014). The integration and interconnection of distributed energy sources to the grid are challenging because traditional power systems are not usually designed to incorporate energy storage at distribution level (Bari et al. 2014; Vineetha and Babu 2014). Another challenge with decentralised generation is that different sources have different characteristics hence a challenge on the stability of a power system upon integration for example fuel cells and micro turbines large-scale wind turbines and solar panels present different characteristics and hence impacts on the grid. Therefore there is a need for a clear definition of standards and procedures for the integration of different distributed energy sources in distributed systems (Bari et al. 2014). DG helps to address twin challenges of generation fluctuations and huge land requirements associated with wind and solar energy resources (Kabeyi 2020a; Kabeyi 2020b; Kabeyi and Olanrewaju 2021b; Vineetha and Babu 2014).

Several recent advances in energy technologies and grid infrastructures have increased the interest in the use of DG resources for grid electricity generation. The exploitation of DG for grid electricity is subject to technical constraints to extend distribution and transmission networks to some areas as well as the deregulation of the electric power sector. There are many benefits of DG depending on the characteristics of the sources like photovoltaic (PV), diesel engines, wind power systems, type, and characteristics of the loads, availably and access of local renewable resources and power grid network configuration. The benefits can be technical, environmental, social, political, and economic benefits like line-loss reduction, system reliability improvement, local revenue, employment and economic benefits and reduction in environmental pollution. The various benefits can be optimised by optimal sizing, optimal location, as well as optimal configurations (Adefarati and Bansal 2016)

3.12. Smart MGs

MGs are defined as electrical networks with ability to operate in isolated mode or grid-connected mode and have their storage units, whose size and capacity depend upon the extent of integrated DG (Bhattarai et al. 2022). An MG is a group of localised generators, loads and storage devices, and loads which can play an important role in the context of the SG because they can be integrated into the main grid and can also supply loads connected during islanding situation (Elgenedy, Massoud, and Ahmed 2015). MGs are linked to DG which has become important because of growing interest in reliable and sustainable energy supply based on more renewable and alternative sources of energy with the objective of reducing stress and losses in power systems. The objective of decentralised generation is to meet local electricity demand by using different energy sources in the power system. This is achieved by the development of MGs which constituted a controlled system of loads and distributed energy sources meant to supply power to the local neighbourhood (Bari et al. 2014). An MG can be said to be a smart power network designed to operate independently from the main or central grid but can also be synchronised to the main power grid besides having ability to operate autonomously. MGs supply energy obtained using DERs to nearby consumers. It is therefore a local form of energy. MGs have emerged as the power system of the future with significant ongoing improvement. Several demand-side management programs can as well be implemented in MGs for energy management (Nasir 2021). The U.S. Department of Energy defines an MG as ‘a group of interconnected loads and DERs that have well-defined electrical boundaries that can operate as a single controllable system within the grid and used to connect and disconnect from the bigger or main grid hence can operate in both grid-connected and island modes’ (Bari et al. 2014). A distributed energy system qualifies as an MG if it obeys the three criteria that include having its own electrical boundary, have a main controller for the subsystem, and have power generation capacity that is higher than peak load and additionally can operate in island mode. Therefore an MG has the capacity to supply enough power in island mode but is still connected to the main or wider grid (Farmanbar et al. 2019).

The concept of an MG is a result of the proliferation of distributed resource (DR) in the form of DG, or distributed storage (DS), or a combination/hybrid of DG and storage which can be operated in three modes namely grid-connected mode, islanded or autonomous mode or between the two modes of grid and island modes. MGs are expected to have multiple generators and loads operating reliably and economically viable as operational power systems (Katiraei and Iravani 2006). The sustainability of MGs is significantly enhanced by the development of SGs.

MGs are designed as small and autonomous subsets of the main electricity grid, which help reinforce the self-healing characteristics of SGs (Logenthiran, Srinivasan, and Khambadkone 2011). Smartening of electricity grids by the installation of intelligent systems and applications into the grid infrastructure improves their reliable, efficiency, and capacity to integrate VREs of energy (Kabeyi 2019b; Kabeyi 2020b). The SG achieves operational efficiency using distributed monitoring and control, and energy management. The use of MGs with smart facilities brings renewable sources of energy into the mainstream, besides increasing efficiency and optimal use of grid facilities through DR and peak shaving. MGs introduce resiliency and autonomous reconfigurability in the electric power grid to guard against man-made and natural disasters (Logenthiran, Srinivasan, and Khambadkone 2011) which is an ultimate benefit of SGs.

Operationally, MGs can be defined as low-voltage intelligent distribution networks made up of distributed generators, energy storage devices, and controllable loads which can be operated as interconnected power systems with the main power distribution grid. They can also be operated as islanded systems if the operate independently or are disconnected from the main power-distributed grid. From the point of view of the main grid, MGs are said to be controlled entities within a power system with the ability to be operated as a single aggregated load and as small sources of electricity or ancillary services that support the main grid. To an electricity customer, an MG is viewed as a traditional low voltage (LV) local distribution network supplying electricity. Properly deployed MGs improve local power system reliability, reduce emissions, support local voltage hence power quality, and reduce costs of power supply. Different MGs may be unique in terms of source of power, type of load. Different MGs could have different types of load and energy sources. Therefore MGs can enable energy resource sharing (Logenthiran, Srinivasan, and Khambadkone 2011). Energy or power sources for MGs includes dies engines, micro or mini-turbines, fuel cells, wind turbines, and photovoltaic sources.

An MG refers to a DER having energy storage facilities and controllable loads and having the ability to operate as a self-sufficient energy network. They help to improve reliability, resilience, flexibility, and accessibility renewable energy resources with the ability to optimise and implement DRPs (Masoudi and Abdi 2022). The use of many MGs in a power system with many energy sources leads to large amounts of data to process and handle. The solution to these challenges is the use of an architecture with a significant degree of intelligence across the grid for effective and efficient electricity distribution. With SGs, the MGs are not used as centralised units but instead they operate as individual systems connected to the main grid by means of individual intelligent nodes (Majeed Butt, Zulqarnain, and Majeed Butt 2021).

The main challenges facing MG design and operation are the use of many small generators with different capacities and characteristics, lack of a dominant and more reliable source of energy during island mode of operation and high demand or need for very quick response for electronically interfaced generator units which has adverse effect on voltage/angle stability if not properly managed. These critical challenges require a power management strategy (PMS) to facilitate a reliable or sound operation of an MG with multiple generators especially during the island operation. Compared to the large interconnected grid, an MG needs faster response of the PMS (Katiraei and Iravani 2006). Distributed energy sources interfacing with an MG can be achieved by the use of rotating machines or electrical coupling using power electronic converters that provide coupling media with the main or host system (Bari et al. 2014). The converters are connected parallel via an MG. Circulating currents are prevented using droop control methods to prevent circulating currents among the converters without critical communication between them. However, the main challenge of the droop control method load-dependent frequency and amplitude deviations which can be solved by the installation of a secondary controller, in the central control of the MG (Bari et al. 2014).

The role of the PMS in an MG is to assign real and reactive power references for generator units, quick response to disturbances and transients and establish the required power generation set points for all the generator sets and provide a means of resynchronisation of the main grid and the MG (Katiraei and Iravani 2006). Since PMS is a function of an SG, it is demonstrated that the development and harmonious operation of MGs is dependent on the level of smartness of the power systems involved. The various technical and management experienced by MGs can be solved by the application of SG components like introducing smart technologies like energy storage devices, use of AMI, application of smart appliances, integration of computational intelligence, application of DR management, and the IoT in the operation of MGs (Bhattarai et al. 2022).

3.13. Integration of renewable resources

Renewable energy sources, particularly wind is solar are huge but variable and intermittent making exploitation to meet the demand difficult. Electricity from renewable sources can from solar, wind, battery storage devices can meet the growing electricity demand and reduce emissions with the right technology in place. The ideal location of these renewable resources may be far from a functional grid for transmission and distribution making exploitation impossible for conventional grid delivery. Under such circumstances, MGs become the best option to distribute renewable electricity from these widely distributed sites that can be joined together to form a bigger electricity distribution network (Majeed Butt, Zulqarnain, and Majeed Butt 2021). Whereas the wind does not blow every time and the sun does not shine always, providing information on electricity demand and weather forecasts made possible by the use of SGs, helps the grid operators to plan for the integration weather-dependent renewable energy to the grid and hence stabilise or balance the electricity networks (UNECE 2016).

The grid needs conventional backup power and huge energy storage so as it can accommodate more renewable energy would need large quantities of conventional backup power and huge energy storage. This is necessary to accommodate the natural variations and intermittence of energy supply in terms of time of day, and season (Phuangpornpitak and Tia 2013).

To realise commercialisation and commercialisation and large-scale use, of renewable energy systems like solar and wind, needs to address issues related to the design and sizing of the system, effective and suitable technical and financial models, balance electricity price for integrating renewable sources. Balance electricity price for integrating PV in an SG system dealing with challenges of using variable renewable systems are limited for several countries (Phuangpornpitak and Tia 2013). The development of power electronics to handle variable electric power by fast semiconductor switching using IGBTs has a significant role to play in the integration of renewable energy sources. The challenge of power electronic circuits is that they may cause harmonics in the power system. As a solution, FACTs devices which include static synchronous compensator (STATCOM), static series synchronous compensator (SSSC), and unified power flow controller (UPFC) can help to improve the stability and reliability of the grid having renewable energy sources. These systems provide filter circuits which mitigate the harmonics injected in the grid caused by power electronics circuits. Additionally, the use of real-time computer controllers equipped with advanced and complex algorithms facilitates maximum extraction of renewable energy power and reduces fluctuation in renewable energy generation. besides protecting storage devices like batteries from over charging which enhances the storage battery life. Renewable energy generation fluctuations can also be adopted by distributing energy generation from a larger geographical area in small power plants instead of large power plant in few places. The challenge of huge land needs can also be taken care of by adopting DG from renewable energy resources (Vineetha and Babu 2014).

3.14. Reduce transmission and distribution losses

The purpose of electricity grids is to transport electricity to the consumer’s point by performing four critical activities. These activities are supporting generation, transmission, distribution, and retailing of electricity. The traditional power system involves the use of large power plants to generate electricity located several kilometres away from consumers and hence must be delivered to distribution networks vial long transmission networks where transmission losses are experienced. In modern grids, electricity is produced in small power plants connected to the distribution grid, in an arrangement referred to as DG. In distribution networks, power is delivered to consumers via low voltage (LV) distribution lines up to the electricity or energy meters (Ackermann, Andersson, and Söder 2001; Costa-Campi, Daví-Arderius, and Trujillo-Baute 2018). Retailing of power oversees or responsible for electricity billing. Energy is always lost through the components of the power systems like cables, electric transformers, etc. (Costa-Campi, Daví-Arderius, and Trujillo-Baute 2018). The shorter the length of travel and resistance, the less the power losses.

Power transmission and distribution losses refer to deviations between electricity generated and electricity delivered to consumers, for reasons that are technical and nontechnical. For many reasons, different countries have different levels of transmission and distribution losses (Adams et al. 2020). The global average for transmission and distribution losses is about 10%, Sub-Saharan Africa (SS) has an average of 18% while some countries have extremely high losses e.g. Togo has about 29% and Congo has an average of 33%. The electricity transmission and distribution losses have increased the demand on demand on power plants to meet the losses in power which has a significant impact on the environment due to increased emissions associated with the increased demand on generation (Adams et al. 2020). Consumption out of the meter is another common loss classified as non-technical energy losses (NTLs), which affects total electricity demand, electricity quality and overall income of the power system (Costa-Campi, Daví-Arderius, and Trujillo-Baute 2018).

The main reasons for losses in power distribution are theft and a weak electricity grid. Theft can be reduced by positive interaction between all stakeholders which can facilitate awareness about the benefits and motivating the consumers to be active participants where they see benefits from connecting to the grid as well as the use of modern technology and infrastructure. SG Infrastructure and devices like energy meters in every bus for power system, monitoring can help the authorities to detect and control electricity theft (Vineetha and Babu 2014). Therefore, smartening the electricity grid will reduce transmission and distribution losses leading to efficiency and reduced avoidable generation as well as related emissions and environmental pollution.

Since electricity consumption by end users varies over the day, consumption has direct implications on electricity losses. Since demand-side management seeks to reduce peak hour power consumption, the effect is to reduce network congestion and system losses. From the perspective of generation, the DG modifies the traditional, unidirectional, downward flows in the electricity system and so it directly affects power transmission and distribution losses as energy is produced at voltage network which is close to the consumers (Costa-Campi, Daví-Arderius, and Trujillo-Baute 2018).

3.15. Smart homes and IoT

Smart homes refer to buildings which may be offices or residential that are equipped with intelligent devices and distributed generators with advanced control systems, whose objective is to maximise internal energy consumption during high demand times. The objective during low demand times, is to export the excess energy in a Smart Building to the grid and support it while generating valuable income for the investors or owners of the buildings (Kabeyi and Olanrewaju 2020b; Kabeyi and Olanrewaju 2022w). The main components of a smart home system are distributed generators, consumer electronics like laptops and lighting bulbs, storage and electric vehicles and smart meters, chargers for electric vehicles and different loads being served (Bayram and Ustun 2017; Kabeyi and Olanrewaju 2022b).

Advances in technology have changed the way energy is produced, stored, saved, and consumed, laying the ground for the deployment of smart energy systems. Incorporating the IoT sensors, digitisation, DG, MGs, and automation is creating a new smart energy ecosystem like SGs.. Just like the internet facilitates information flow and data interchange between computers connected to the same network, the SG is also powered by a web of interconnected electric grid devices (Kabeyi and Olanrewaju 2022d).

In general, the IoT refers to a collection of internet-enabled devices that facilitate the collection of data and information, data pipelines, and real-time information transmission between devices and other people (Particle Industries 2022; Skopik and Smith 2015). Therefore, the IoT is a connection of people and things at any place and time, by use of any network and any service. It is further said to be a global network infrastructure of Internet-enabled entities with web services. The SG is a data communications network which is integrated with the power grid to collect and analyse data that are acquired from transmission lines, distribution substations, and consumers (Ghasempour 2019). SGs are a typical application of IoT technology in the electricity sector and if well implemented can resolve several challenges facing the traditional grids like the security of supply, outages, high greenhouse gas emissions, and other issues (Particle Industries 2022; Skopik and Smith 2015).

The facilities that enable the operation of IoT include sensors, actuators, RFID tags or any device that requires a communicating interface and a computing ability, into the Internet. It is now possible to access, manage and communicate through the internet -based protocol like IPv6, UDP/TCP, HTTP, and others for objects like fridges, heaters, windows, switches, washing-machine, etc. For devices compliant with the IEEE 802.15.4 standard, the IETF (Internet Engineering Task Forces), several protocols are proposed for their efficient integration and at different layers to the Internet. These protocols include Constrained Application Protocol (CoAP) which is a specialised web transfer protocol used with constrained nodes and constrained networks; Routing Protocol for Low-Power and Lossy Network (RPL), and IPv6 over Low Power Wireless Personal Area Networks (6LowPAN) which is an adaption layer used to support the IPv6 protocol on IEEE 802.15.4 networks. For functions that cannot support internet protocol (IP) or functions that cannot be updated to support the internet protocol, gateways where proprietary non-IP stack protocols like Zigbee v1, HART, Z-Wave, etc., are translated to/from IP stack protocols can be used but are expensive (Kumar 2022).

SGs can use wireless sensor networks (WSNs) unlike traditional communication technologies since it is cheaper, fast to deploy, has high flexibility, and has aggregated intelligence via parallel processing capabilities (Kabeyi and Olanrewaju 2022d; Venticinque and Amato 2018). The IoT in SGs refers to the application of WSNs, smart meters, actuators and components with ICT. The main limitation or challenge with integration of the IoT technology within the smart power grid introduces the cost of large data processing. The data includes end users load demand, power lines faults, network’s components status, scheduling energy consumption, forecast conditions, advanced metering records, outage management records, and enterprise assets. SG utility companies should be equipped with software and hardware capabilities to efficiently handle data collected (Venticinque and Amato 2018).

The IoT applies a bidirectional flow of energy and information within the SG to get deeper insights on current and future/predicted actions whose aim is to improve energy efficiency and reduce overall cost. Big data technologies must be adopted by the SGs for accurate monitoring and scheduling, information from the grid within short intervals (Kumar 2022; Venticinque and Amato 2018). The ICT infrastructure should have a high degree of reliability to avail available data for information extraction needed to perform critical functions like fault detection and fault resolution. Security is an important requirement for the ICT to avoid or limit failures from cyberattacks or by combined attacks to the grid and ICT infrastructures. It is necessary to guarantee high reliability for the health and industrial systems (Kiran and Rao 2018; Venticinque and Amato 2018).

The IoT is used to describe common items like medical wearables, housewares, and equipment the monitor users’ physical condition, automobiles and tracking devices among others that are connected to the internet and identifiable by other devices in the system. Through the IoT, it is possible to collect data from connected devices and products and determine the usage by and use the same in energy planning and market campaigns. At the industrial scale, farmers can apply IoT sensors into fields to monitor and hence control soil parameters like nutrients or fertiliser use and needs (McGinnis 2020). The loT, Internet of Everything (loE), and Internet of Nano Things are new approaches that incorporate the internet into personal, professional, and societal life. ‘IoT’ or ‘Internet of Objects’ represent electronic or electrical devices that vary in size and ability and are connected to the internet in a way that goes beyond mere machine-to-machine communication. Through IoT, one can access information any time wherever you are connecting devices via real-time information generated by the interconnected devices (Lo Cascio et al. 2021). Smart homes are an important segment that has significantly been affected by the IoT. Smart home-IoT is a new domain created when smart homes are connected to the IoT (Choi et al. 2021). The main benefits of smart homes are energy efficiency and comfortable living. Smart homes are created by integrating ICTs and energy technologies for home or end-user applications.

A smart home refers to a residential environment where information and communication technologies are applied by the resident for convenience, security, entertainment, and comfort needs. This enables home owners to employ well-designed management functions for optimal control and maintenance of their homes (Choi et al. 2021). Through the integration of recent and modern Information and Communication technologies (ICT) and energy technologies in the housing environment gives rise to new applications and services. Examples of technologies in smart homes include ubiquitous computing technologies, that make it possible to connect objects anywhere and at any time, and apply small sensors to provide information to entire network systems making users part of the network (Shapsough and Zualkernan 2019). Therefore, users become part of a system of interconnected computing machines sharing information via the network without traditional forms of communication which is the main concept behind the IoT. Therefore, based on the IoT environment, equipment or home users can interact with objects or devices and services in smart homes (Choi et al. 2021; Neagu et al. 2017).

IoT uses computation and communication technology to make life easier, automatic, and handy by exploiting the internet revolution. The development of the SG and its components have created demand for technology to enable interaction with system components efficiently, reliably and in a smarter way, although these technologies come along with new security challenges like threat of data tampering, impersonation, overdoing, privacy breaches, authorisation, and cyber-attack (Particle Industries 2022). This implies that the SG-based IoT requires services like authentication, data confidentiality, user’s privacy, and data integrity to avoid any security risk (Particle Industries 2022). The use of IoT facilitates enhanced customer experience and efficiency of service delivery by enabling flexibility and easy interaction with the grid which leads to cost reduction. It is therefore observed that the IoT further makes the SG smarter (Kabeyi and Olanrewaju 2023; Majeed Butt, Zulqarnain, and Majeed Butt 2021).

The IoT has enabled the evolution from connecting people and machines to connecting smart objects, hence IoT communications have evolved to M2M communications with objects in the IoT system being anything/device/entity that is equipped/embedded with computational, storage and communication capabilities through sensors, mobile phones, actuators, laptops, printers, computers, car, fridge, ovens among others. Smart objects in the IoT are interconnected via proprietary non-IP solutions in different applications like Zigbee, HART/Wireless HART, Z-Wave. The IoT aims at connecting objects or devices on a larger scale using IP-based solutions like IP, TCP/UDP, either directly or through gateways if at all an IP support is not possible on condition that they can communicate or interact with each other communicating party over or through the Internet (Kumar 2022).

The IoT facilitates smart energy solutions needed to strengthen SGs through functions like

1. Provision of real-time alerts with respect to meter, grid damage or system outages

2. Modification of supply and price based on data insights Power quality monitoring and control

3. Gathering information necessary for system optimisation e.g. factors like tilt angle and direction of rotation for wind power system

4. Greater energy savings in the system

5. Software installation and continuous updates to keep the system safe and functional (Particle Industries 2022)

6. Enhancing the predictive analysis by collection and analysis of data while at the same time-varying variables like the weather, and individual panel performance in solar systems

7. vii.) Attaching monitors to individual solar panels, wind turbines, and other equipment providing feedback on performance to streamline maintenance

8. Theft detection and prevention into the twenty-first century.

The IoT solutions many and may be unique to specific power system. It functions through the ability to monitor important and relevant indicators to the power system like availability of energy and consumption, on a real-time basis. Other than monitoring, control is another key feature of the IoT, especially the ability to remotely download and as well as install critical software updates through the cloud and management of vital asset data from any location. The IoT allows businesses to access real-time alerts on deterioration for timely repairs to crucial important infrastructure which improves the overall system efficiency (Kabeyi and Olanrewaju 2022d). The main risk of the IoT in SGs is that it can lead to disasters as it becomes exposed to cyber-attacks, because its monitoring and control can be done over standard internet-based protocols and solutions and can rely on public communication facilities which can cause financial loses to the utility and damage connected assets (Kabeyi and olanrewaju 2022r).

3.16. Electrification of transport and smart charging

Electric vehicles introduce both opportunities and challenges for power systems. Peak energy demand can be significantly increased if many electric vehicles are charged at the same time or uncontrollably causing overloading and power loss. The solution is to employ electric vehicles as dynamic loads used to offer balancing services to the power system. For full realisation of the capability of electric vehicles as a flexible or dynamic load, there is need to introduce smart charging procedures which can be executed by the SG power system (International Renewable Energy Agency 2019). The transport industry, particularly cars, is one of the biggest contributors of greenhouse gas emission, hence the need to shift to the use of electric vehicles. Electric vehicles use chemical energy stored batteries that can be recharged for use in vehicle propulsion and powering other automotive systems (Kabeyi and Olanrewaju 2022a; Kabeyi and Oludolapo 2020a; Kabeyi and Oludolapo 2021b). Although various fuels and technologies are under development for the transport sector, electric vehicles represent one of the most feasible options other than using grid electricity for charging, electric vehicles have the potential to act as independent distributed energy sources for the grid (Kiran and Rao 2018). Electric vehicles offer an efficient opportunity to reduce carbon emissions in the transport sector and hence mitigate climate change. The share of electric vehicles in transport is increasing globally with Europe having over 15% sales share by mid-2021 (Kabeyi and Olanrewaju 2021d; Kabeyi and Olanrewaju 2021f; Sabine et al. 2021).

Vehicle batteries can be charged using the grid by plugging the vehicles into the grid and using regenerative braking. Electric vehicles can be classified based on charging typologies. They are battery electric vehicles (BEV), plugin vehicles (PHEV), Hybrid Electric Vehicles (HEV), and Fuel cell Electric Vehicles (FCEV) (Kiran and Rao 2018). The main motivation for the electrification of transport sector is that it accounts for about 30% of world energy consumption and 72% of global oil demand making electric vehicles a key avenue for greenhouse gas emissions control and the attainment of the global climate targets (Kiran and Rao 2018). The main challenges facing electric vehicles include grid infrastructure, the communication, and control (Lopes, Soares, and Almeida 2011; Majeed Butt, Zulqarnain, and Majeed Butt 2021). Electric vehicles promise to play a key role globally in the energy transition because of the growing concern about fossil fuel depletion and related emissions. Since vehicle battery energy is not fully used each day, they have a potential to provide peak shaving service (Uddin et al. 2018). Smart charging can be centrally done through aggregators or can be decentralised using decentralised control structures. Aggregators are used to achieve optimal scheduling of each electric vehicle (EV). In decentralised charging systems, electric vehicles choose their charging methods without contacting the central controller or other linked electric vehicles. Smart charging using both centralised and decentralised systems can effectively reduce energy costs and prevent the overloading of grid components by shifting peak demand (Bhattarai et al. 2022)

The main challenges facing electrification of transport and application in peak shaving are:

1. The electric vehicles can only deliver power to the grid when the vehicle is packed, and they are currently not widely deployed.

2. It is not practical for a single vehicle to meet peak load demand alone hence many vehicles and infrastructure must be deployed and controlled together by a third party.

3. It is a technical challenge to synchronise the charging and discharging of a multitude of electric vehicles simultaneously.

4. Lack of critical infrastructure for grid integration of electric vehicles especially in highly urbanised regions (Uddin et al. 2018).

5. Charging can cause direct stress to the grid as it is often done at home, commercial, and public ideally designed for other applications (Lopes, Soares, and Almeida 2011; Majeed Butt, Zulqarnain, and Majeed Butt 2021).

However, when parked and plugged into power grid, electric vehicles absorb energy and store it in batteries. By provision of two-way power flow capability, these vehicles can also supply power back to the electricity grid in a concept popularly known as V2G (Vehicle to Grid) concept (Lopes, Soares, and Almeida 2011).

Since SGs are equipped with advanced technologies for communication, metering, and control, they offer electric vehicles the ability to charge and act as a flexible energy source for the grid (Young 2017). Therefore if well planned and with adherence to standards set, electric vehicles charging can improve power quality and the performance (Lopes, Soares, and Almeida 2011; Young 2017). An important feature or capability of SGs is the accommodation of support of electric vehicle services making them an important tool in the energy transition (Kabeyi and Oludolapo 2020a). The electrification of transportation is becoming a reality with advances in battery storage technology and the development of SGs. The main motivation is that the transport sector accounts for about 30% of world energy consumption and 72% of global oil demand making electric vehicles a key avenue for greenhouse gas emissions control and the attainment of the global climate targets (Kabeyi and Olanrewaju 2022f; Kabeyi and Olanrewaju 2022m; Kabeyi and Oludolapo 2020c; Kiran and Rao 2018).

Electric vehicles have continued to increase globally with 10 million electric cars by the end of the year 2020. Registration of electric cars increased by 41% in 2020, even in the face of the global pandemic-related global economic downturn and reduction in car sales by 16% (International Energy Agency 2021). About 3 million electric accounting for a 4.6% share of global sales were realised with Europe overtaking China as the world’s largest market for electric vehicle (EV). Electric bus and truck increased in numbers globally to reach 600,000 and 31,000 respectively (International Energy Agency 2021; Taliotis 2020). The global share of electric vehicles is increasing with sales rising to 15% of sales in Europe mid-2021 mainly consisting of plug-in hybrid electric vehicles (PHEV) and the battery electric vehicles (BEV) (Sabine et al. 2021).

Electrification of transportation is becoming a reality with advances in battery storage technology and the development of SGs. Therefore, a key requirement for successful energy transition via the electrification of the transportation sector is the development of the SG. The exact amount of actual number of emissions reductions due to the electrification of transport vehicles dependent on when and where drivers charge the vehicles and the composition of electricity mix (Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022d; Kiran and Rao 2018).

3.17. Smart cities and streetlight automation

Smart devices are key to efficient energy management and optimisation while the intelligent application of SG is a key requirement for the establishment of smart cities. Smart cities have been identified as the ultimate solution to complex challenges facing urban centres. Cities are important entities because it is estimated that by the year 2050, about 70% of the world population will be living in urban centres or cities (Farmanbar et al. 2019). There is growing interest in linking interfacing items via networks. The objective of smartening devices is to enable sharing of information or access with other devices to facilitate smart decisions with available internet and communication infrastructures. Smartness of a city refers to the desire of improve the quality of life in a city and living standards of the city residents in terms of information use and communications technology (ICT) capabilities and applications, although the use of ICT per se does not constitute a smart city (Farmanbar et al. 2019). The main challenges facing urbanisation which should be resolved are shortage of resources, energy management, waste management, obsolete or aging of existing infrastructures, environmental and human health problems among others (Farmanbar et al. 2019).

SG technologies are playing an important role in urban low-carbon transitions. As they are seen as clean innovations and indispensable strategy to realise the mass integration of renewable energies in cities (Quitzow and Rohde 2021). SG solutions have become useful in the development of smart cities. As the Growing population has created jam-packed cities. As technology continues to advance, the concept of a smart city is quite appealing. To realise the dream of a smart city, require advanced power networks that can handle the plethora of information transmission requirements (Partida 2022). A smart city can be defined as a city that takes advantage of computers, information, and communication technology to generate interactive and responsive infrastructural systems and public services. The goal of a smart city is to use critical data and information to ensure efficient delivery of utilities, like water, public road transport, power supply, and other consumer services.. Therefore smart electricity solutions form the basis of smart city development and transformation (Partida 2022; Quitzow and Rohde 2021). According to Farmanbar et al. (2019), the smart city concept elevates the intelligence of the city by connecting the physical environment, social, business, and ICT infrastructure for the city and balances the demand and supply of different functionalities (Farmanbar et al. 2019; Ma et al. 2021).

Smart cities like Berlin are increasingly relying on high-tech innovation to deal with urban problems like transport congestion, people’s participation in governance, and environmental management. City administrations are putting in place measures and strategies like opening urban laboratories, creating innovation spaces and other sites for technological experimentation to attract ICT companies and compete in the race for digital modernisation and progress. Smart urbanisation is rapidly being developed in many countries and major cities globally in both developed and developing countries (Partida 2022; Quitzow and Rohde 2021).

Cities around the world spend significant energy resources on street lighting and traffic control. The use of SGs can enhance efficiency, reliability and hence reduce the energy consumption on street lighting. This can be achieved by seamless connection to different suppliers’ sources, use of on/off timing control facilities equipped with the ability to synchronise with an astronomical clock. Others are the use of voltage dimming facility that responds to time-setting and traffic condition. Additionally, each lamp can be facilitated with elements for power factor improvement as well as individual lamp control. This combination leads to significant saving in energy costs. Installation of street light automation (SLA) systems can lead to energy savings by as much as 50% based on experience from similar programs (Kappagantu, Daniel, and Suresh 2016).

Smart power grids are adding value to the concept of smart cities by enabling the following services and products to urban dwellers.

1. Efficient power transmission and distribution within cities

2. Better security measures and infrastructure like affordable street lighting

3. Faster restoration of electricity whenever disruptions are experienced.

4. Efficient and cost-effective service delivery through cost reduction and wastage minimisation

5. Reduced electricity tariffs and lower energy costs

6. High integration of urban renewable energy sources like solar power from rooftops.

The concept of smart cities is realised by using digital technologies like the IoT, artificial intelligence (AI), automation, and 5G, which facilitate a two-way communication between various utilities in a smart city and the dwellers. These technologies are already in use by industries, like health care. The development of smart cities relies on key power key electricity grid technologies like electric cars, distributed energy or electricity storage, smart meters, smart appliances, smart buildings, and decentralised generation. With global SG technology market expected to reach $55.9 billion by 2026, it is evident that SG technology has an important socioeconomic and technical role to place in the smart cities development (Farmanbar et al. 2019; Partida 2022).

3.18. Grid integrated energy storage

Energy storage is a very important component of SGs because if renewable energy is not extensively stored, its usage becomes less feasible. The main benefit of SGs is the ability to balance the variable and intermittent renewable sources of energy whose performance in balancing is enhanced by storage of some quantities of energy by the grid. Storage is an important component of a modern grid with Japan having 15% of stored energy for the grid, Germany 10%, and the USA about 2% of grid capacity. Energy storage is an important function of demand side management, with power storage being engaged in the speed of feedback, spinning reserve, and frequency adjustment. Energy storage in various forms like compressed air, pumped hydro, battery, super capacitors, and flywheels have wide engineering applications and can seamlessly be integrated in smart power grids. Electric springs are examples of innovative equipment that have been developed and proved effective in supporting SGs by considerable absorption of renewables by facilitating the harmonising of demand-supply (Kabeyi and Olanrewaju 2022k). According to Venkataramani et al. (2016) adding compressed air energy storage (CAES) to multi-generation systems can improve the sustainability and use of renewables when used with SGs.

Energy storage technologies have a significant potential role to play in achieving load levelling, like matching intermittent source of renewable energy with customer demand as well as storage of excess power for peak time use or when the variable resource is not available. Pumped hydro storage and compressed air energy storage are notable examples of mechanical methods of energy storage-based that can be used to supply peak time power. CAES is an efficient storage system that can regenerate up to 80% of the electricity production needed to support variable renewable (RES) based power plants. The ESSs are used to store excess energy during off-peak when power is cheap and from clean sources to compress the air and pump in umped storage for use in peak time when demand and price of power is high. For pumped storage, the water that was pumped upstream is allowed to run through turbines to generate clean power while for CAES, high-pressure air stored in an underground reservoir or tank is released to drive the turbine, and supply power for peak time use or when the renewable sources decline. This is the same for pumped storage power plants (Ma et al. 2021; Venkataramani et al. 2016).

Besides the mechanical storage methods, other storage methods are battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) which can be configured as dispersed energy storage for use in vehicle-to-building (V2B) and vehicle to grid (V2G) operating mode where stored energy in batteries is used to supply power during the peak or when renewables decline in supply. With SGs and dynamic energy storage/management by means of V2B, V2G, and applying BEVs and PHEVs via peak load shifting, energy expenses can be controlled why demand side management can be enhanced by optimum use of the storage facilities whose functionalities can be significantly enhanced by the use of SG technologies and products. the purchase price of the electricity for the client and vehicle owner would decrease. Technological advances in battery story and development of SGs will ultimately make storage as a reliable source of grid electricity and hence a key strategy in the energy transition (Farmanbar et al. 2019; Kabeyi and Oludolapo 2020a).

3.19. Smart grids and Industry 4.0 and Industry 5.0 applications

The first industrial evolution was ushered in by the invention of the steam engine in the eighteenth century which significantly transformed the industry and transport sector while the introduction of electricity led to the second industrial revolution. These two revolutions paved way for mass production and mechanisation of functions for the first time, and these drove social change because of urbanisation (Gebhardt et al. 2021; McGinnis 2020).

The third industrial revolution was ushered in by electronics, information technology systems and industrial automation (TWI 2022). The third industrial revolution was a result of wider use of information technology and electronics products in the industry. This revolution began in the 1950s and it saw the emergence of computers and digital technology. This further accelerated the automation of manufacturing and the disruption of service industries like banking, communication, and energy (Gebhardt et al. 2021; McGinnis 2020).

The Fourth Industrial Revolution (4IR) or Industry 4.0 is identified with twenty-first century rapid transformation of technology, industries, and societal patterns as well as processes and systems because of growing interconnectivity and smart automation. The term was popularised by Klaus Schwab in 2015, who was the founder and executive Chairman of the World Economic Forum . He asserted that changes realised are more than just improvements to efficiency and express a shift in industrial capitalism. The 4IR is a result of advances in IoT and cyber-physical systems (CPS). It is characterised by the application of emerging technologies that revolutionise the production and operation systems from machine-dominant manufacturing to digital-dominated manufacturing and operations. It can be said to be an integration of technologies such as CPS, IoT, Big Data, and Cloud manufacturing. In addition, industry 4.0 is also concerned with the whole concept of data and resource acquisition, sharing, use, and organisation that leads to faster, cheaper, more effective, and more sustainable product and service deliver (Gebhardt et al. 2021; McGinnis 2020).

The overall result of 4IR is growth in automation, better communication, self-monitoring, and application of smart machines which can analyse and diagnose issues without little or no human intervention. The revolution also represents a social, political, and economic shift from the digital age of the late 1990s and early 2000s to a connectivity-embedded era distinguished by the omni-use and commonness of technological use throughout society. The 4IR technologies have the potential to connect billions of people globally to the web and significantly improve the efficiency of doing business (TWI 2022).

Through automation, systems are augmented with wireless connectivity and sensors to use for monitoring and visualisation of the entire system and process functions as well as make autonomous decisions. With the use of wireless connectivity and the augmentation of machines will be greatly enhanced by the full roll out of 5G which promise to provide faster response and near real-time communication across systems (TWI 2022).

Beyond industry 4.0 is the industry 5.0 which involves the wider use of robots and smart machines which allows humans to work better, efficiently, and smarter. The industry 5.0 will make the factories working laces for creative people to work and create a more personalised and human experience for the workers and customers through connecting man and machines. It is projected that Industry 5.0 will make it necessary for about 60% of logistics, manufacturing, and supply chains, mining, agriculture as well as oil and gas sectors employ chief robotics officers by 2025 (TWI 2022). The operation of SG technology places them between industry 4.0 and Industry 5.0 but with the potential to transform to industry 5.0 technology as an intelligent man-machine system with automated operation.

Industrial revolution in the 4th/Industry 4.0 is a new turning point in appropriate technologies applied in all fields and industries including power generation. In the energy sector, Industry 4.0. requires that energy and power generation, transmission, and distribution should be more efficient and of high reliability with the application of next-generation software and hardware resulting from the concept of the 4IR (Tuttokmaği and Kaygusuz 2018). The use of SGs enables flexibility, reliability, and clean energy systems that are sustainable and highly efficient. The main components of the intelligent energy network system that reciprocate with industry 4 are the Cyber-Physical System, M2M (machine to machine), the IoT which result in intensive application of technology at all levels in the power system. Industry 4.0/4 Industrial Revolution and SG commonalities include elements of optimisation, systems automation, efficient use and management of energy, application of intelligent production, and use of the internet (Tuttokmaği and Kaygusuz 2018). Therefore, the overall effect of application industry 4.0 principles in SGs includes better system operation, higher energy efficiency, reduced costs, reduced greenhouse effect, reduced downtime with reduced human intervention, reduced loss/leakage rates, improved energy quality, effective management of generation and storage systems, intelligent meter reading and load management and real-time supply-demand management.

SGs provide an intelligent infrastructure that has potential to transform power systems into more secure, efficient, reliable, flexible, and sustainable energy systems. The SGs are equipped with smart devices and smart metering like sensors and sensor networks. They are installed at multiple places along the grid like transformer customer premises, substations. The sensors monitor the state and operational health of the grid infrastructure by monitoring various parameters like temperature, quality disturbances, and outage detection. This sensing functions enable control centres to receive accurate information about the actual condition of the grid (Venticinque and Amato 2018).

3.20. V2x technologies

Electric vehicles apply an electric drive traction system consisting of one or more devices for storage of electrical energy or electrical energy conditioning devices or one or more electrical machines meant to transform electrical energy often in stored form to mechanical energy which is transmitted to vehicle wheels to drive the vehicle. This is an all-electric vehicle, or a pure electric vehicle (BEV, for Battery Electric Vehicle). Storage often requires regular recharging by connecting the vehicle to an electricity grid or by standard exchange of battery (Ouaissa, Ouaissa, and Houmer 2021). Electric vehicles are designed to limit the use of Internal Combustion Engine Vehicles (ICEV) and limit dependency on oil as an energy source. Energy for electric cars is stored in fuel Cells (FCs), and or Ultra-Capacitors (UCs) as opposed to fossil fuel which is stored in a fuel tank. The main components of an electric vehicle system are the motor, controller, charger, power supply, and drive train. Electric vehicles available include the lower-end electric vehicles like Nissan Leaf and higher-end electric vehicles like the Tesla Model S. The EVs are cleaner, can be used in peak load shaving, reduce grid infrastructure requirements, act as mobile DG or electric power, etc. but their disadvantages include limited range, need new infrastructure for development, have long charging time; and are associated with adverse battery effects (Ouaissa, Ouaissa, and Houmer 2021; Parazdeh et al. 2022).

There are several challenges associated with charging electric vehicles via the SG. These challenges include overloading, imbalance, under-voltage, etc. These issues are with EV charging are managed via control called Vehicle-to-Grid (V2G) technology. The technology enables electric vehicles to charge and supply electricity and services to the grid, via an aggregator, for compensation (Ouaissa, Ouaissa, and Houmer 2021). There are several V2G technology subsets like Vehicle-To-House (V2H) where the vehicle is in the owner’s residence, Vehicle-To-Building (V2B) in which the vehicle is in a commercial building. In these arrangements, the battery power supplements the electrical charge of the local buildings without transferring power to the grid in the event of power failure in the grid (Ouaissa, Ouaissa, and Houmer 2021)

The V2X technologies are associated with grid-connected vehicles like the Vehicle to Grid (V2G), vehicle to house (V2H), and vehicle to vehicle (V2V), where V2G refers connecting an electric vehicle to the electricity grid for battery charging and discharge. The vehicles are referred to as grid-connected EVs (GEVs) (Bhattarai et al. 2022; Kabeyi and Olanrewaju 2022b). The EV represents a significant and radical change in the transport sector engine-driven vehicles and in the production of EV. The reason is that an electric vehicle is powered by electricity which can be generated from many sources like hydropower, wind, nuclear, wind, photovoltaic, etc. An electric vehicle needs more energy compared to the electrical needs of houses for heating and lighting. On the other hand, electric vehicles can be considered as electricity storage systems for the grid. Electric vehicles store electricity that can be used during peak periods to stabilise the grid. The main objective is to meet energy needs of customers under the constraint of not destabilising the grid (Ouaissa, Ouaissa, and Houmer 2021)

As the interest in alternative sources of energy and technologies increases, there is potential for massive penetration of electricity into the grid and widespread use of DER (distributed energy sources) is expected soon. For load management and resource scheduling, a collection unit, VPP (virtual power plant) may be applied. The vehicle-to-grid (V2G) technology enables fixed or parked voltage batteries to serve as distributed sources, for storage and release of energy at appropriate times, in bidirectional power exchange between the AC mains and DC EV batteries. The bidirectional exchange of power is realised by the use of bidirectional electronic power converters connecting the grid and electric vehicle (EV) batteries. Most bidirectional converters for V2G applications use two dedicated power conversion phases – an AC–DC two-phase conversion step that assists in modifying the power factor, followed by a bidirectional DC–DC conversion phase, to provide voltage matching (Parazdeh et al. 2022). The bidirectional electronic converters, used i.e. AC–DC (BADC) and DC–DC (BDC), facilitate G2V and V2G electricity transmission between electric vehicles and the grid. Bidirectional converters facilitate high-efficiency energy conversion and in the e transition from conventional to electric vehicles, enable the realisation of a greener environment (Ouaissa, Ouaissa, and Houmer 2021).

The V2G is a promising technology that enables idle or parked electric vehicles to act power plants for grid power supply, with the ability to store electricity and release it at appropriate times, to facilitate power exchange between grid and the electric car/vehicle. This approach increases generation capacity and improves power system stability, efficiency and reliability of the grid (Parazdeh et al. 2022). The development of SGs and growth of electric vehicles has generated momentum for the growth of vehicle-to-grid (V2G) technology. With V2G, one can use his vehicle to power his home, charge phones, power lights, and even operate the fridge during the time of high electricity price or a grid outage and supply excess power to the grid when prices are favourable. The vehicle-to-grid technology (V2G), which is also known as vehicle-grid integration (VGI), creates an extra power source when weather-dependent renewable energy sources are not available. A home can use solar power to generate electricity during the day but use the electric vehicle to supply a secondary source of power if needed, e.g. at night and sell the excess to the grid (Parazdeh et al. 2022).

Peak demand generally occurs between 5 and 11 pm for most grids globally. This is the time when most private and public vehicles are parked at homes or parking stations. At this period, the vehicle-to-house (V2H) technology will enable the parked vehicles to supply electricity to home to meet demand peak demand while any excess can be exported to the grid. The electricity prices are generally lower during off-peak hours. This is therefore used to charge the vehicle can be for peak time use. The car can also be charged using solar energy like rooftop solar PV. The V2G technology can be applied by having electric vehicles clustered via an aggregator to offer grid power services like voltage regulation, load levelling, and peak shaving, at a lower cost and with less environmental impact which makes the SG technology ideal for deployment of V2G and hence play an important role in the energy transition (Bhattarai et al. 2022; Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022e).

The communication between the grid and electric vehicles facilitates sharing and exchange of information with respect to the state of charge of electric vehicles, availability of recharging stations, and user data. Electric vehicles are in most of the time in a state of rest in the garages of the houses or in the parking lots, hence they can be easily charged by the G2V system and be later used as a source of charge for the grid. The communication between electric vehicles and SG takes place in V2G discharge mode, from the vehicle to the grid, with the vehicle as a source of DG and G2V which is charging mode. Drivers benefit from the use of electric vehicles since electricity is cheaper than petroleum power. The electric vehicles also provide income to vehicle owners by selling power to the grid (Ouaissa, Ouaissa, and Houmer 2021).

4. Challenges of SGs

SGs apply modern cutting-edge technology to address multiple challenges of the traditional grid while at the same time providing opportunities to improve their efficiency and reliability. However, several technical and socioeconomic challenges limit the development and application of the SG (Bhattarai et al. 2022; Kabeyi and Olanrewaju 2022b). SGs employ power electronics technologies like FACTS and RACDS, efficient ESSs, etc. which have high initial cost requirements.

Technical challenges in the operation of SGs include database management and cyber security. Lack of consumer understanding of operation and opportunities of SG technology is a lack of consumer understanding about the SG, hence the need to educate the public on the concept of SG, applications, opportunities, and its role in the energy transition. For consumers to effectively participate in DR and other services requires training (Bhattarai et al. 2022; Kabeyi and Olanrewaju 2022d; Kabeyi and Olanrewaju 2022m). The challenges facing the development and application of SGs are summarised in Figure 7.

Figure 7. Challenges of SG development and use.

Figure 7 shows the various challenges facing SG development. The challenges are inadequate grid infrastructure, lack of knowledge and skills by industry workforce, limited capacity of ESSs, database management to secure user confidentiality and privacy, cyber security challenges like viruses and cyber-attacks, high initial capital; investments, lack of supporting policy and legal framework, and lack of consumer awareness hence ignorance of immense opportunities offered by SGs.

SG development is both a social and technological endeavour. The introduction of SGs has profound effect on rules, regulations, norms, socially and culturally guided patterns of thinking and operation of power systems since they are highly institutionalised. SGs development require the development of new standards and regulations, new policies, and new market mechanisms while at the same time new technologies must be natured and allowed to mature with minor disruptions (Rohde and Hielscher 2021). Stakeholders like technology manufacturers and ICT developers, must develop use friendly and effective novel technologies and business models in power system operations and maintenance (Kabeyi and Olanrewaju 2022b; Kabeyi and Oludolapo 2020a; Lund et al. 2017).

There are several challenges affecting SG development and deployment. There is a need for greater awareness among policy makers and stakeholders on the various capabilities and benefits of SGs to facilitate energy-efficiency and renewable resources in power systems (Nasir 2021). Rapid changes in information and communications technologies and how they are being deployed in other areas of an economy like manufacturing, finance, healthcare offer new solutions for faster deployment of SG technology (Nasir 2021). Developing countries are most affected by the challenges of SG development as they are still grappling with other important developmental and technical issues like extreme poverty, limited access to capital, political instability, government bureaucracies, high level of power theft and other system losses which may have precedence and hindrance to investment in grid smartening (Nasir 2021; Ponce-Jara et al. 2017). The main technical and socio challenges or limitations of SGs include interoperability issues, cyber and physical security, high costs, confidentiality, and privacy challenges among others.

4.1. Cost challenges

The biggest impediment to the development and implementation of SGs is cost. The main cost elements in SG development are associated with the power transmission and distribution system, electricity metering, and critical technologies. In economic analysis and financial feasibility, a country’s capacity to pay for the development cost for SG infrastructure is paramount which ultimately disadvantages the developing countries in implementing SG infrastructure (Majeed Butt, Zulqarnain, and Majeed Butt 2021; Young 2017). Smartening of the traditional grid requires the integration of additional sensors to the infrastructure which is an expensive investment undertaken by distribution grid operators (International Energy Agency 2011; Skopik and Smith 2015).

4.2. Cyber security

There are increased possibilities of remote operation of SG power systems because the grids are large-scale system with participants widely spread between power plants and electricity consumers and devices which also creates demand for protection of resources against theft, abuse, and malicious activities (Bari et al. 2014). The Electric Power Research Institute has identified power system cyber security as one of the greatest issues facing SG. It is necessary to identify weaknesses of the SGs exploited by attackers by use of SG Systems Treats Analysis and by integration of Systems Security Threat Models. There are various approaches used to address cyber-physical security issue for Wide-Area Monitoring and protection and control which are vulnerable to a coordinated cyber-attack. Overall, it is necessary to assess the SG security by review of its methodology to identify weaknesses (Majeed Butt, Zulqarnain, and Majeed Butt 2021). Since SGs are deployed across the value chain, there is an increase in points of interconnection with other information networks which exposes the system to the potential threat of cyber-attack on important power management systems and infrastructure (International energy agency 2015).

The SG is heavily dependent on ICT which ultimately increases the complexity and the number channels for possible cyber-attacks. The cyber-attacks may target the distribution infrastructure not necessarily to cause power blackouts but other destructive disruptive activities like energy meter manipulation, blackmail, power supply disruptions, damage of equipment, damage of distribution or customer equipment (International Energy Agency 2011; Skopik and Smith 2015)

Therefore, it is necessary to ensure that cyber security is an essential aspect of any SG design and operations (UNECE 2016). Interoperability and cyber security can be achieved only through rigorous implementation of various standards.

4.3. Interoperability

The communication infrastructure for SG should meet specifications in terms of time synchronisation, data delivery efficiency, latency reliability, and multicast support. Additionally, the main challenge in networking communications in SG is interoperability (Bari et al. 2014). Rigorous implementation of applicable standards is an effective measure to achieve interoperability. The NIST has put in place interoperability standards in areas like advanced metering infrastructure (AMI), end-to-end security, metering, communication between control centres, substation automation and protection, EMS interfaces, power system control operations information security, PMU communications, electrical and physical interconnections between utility and DG, security for intelligent electronic devices (IEDs), cyber security standards and guidelines for federal information systems and bulk power systems, HAN device communication, measurement, and information model and SGIP catalogue of standards.

Each country should develop their standards for smooth implementation of SG considering their existing standards and for easy implementation. However, internationally accepted standards and security should also be put in by all countries involved in the SG implementation to make the power grid a homogeneous global grid (Vineetha and Babu 2014).

4.4. Confidentiality challenges

Access Control and Identity Management is needed for the confidentiality of data transmitted via SGs. There is a need for authentication to verify the identity of the receivers of and avoid any disruption or exploitation. Only authenticated users should be allowed access to the control center for transmission, and distribution grids (Umar, Singh, and Sanober 2016).

4.5. Privacy and security policies

With wide scale interconnectivity and system access including the growth of IoT associated with SG development, privacy, and development of far policies for all stakeholders is a real challenge as objectives and needs may differ and even conflict among stakeholders (Umar, Singh, and Sanober 2016). Therefore, there is a huge necessity for suitable security policies to establish relationships between the consumers, utilities, generating companies, transmission firms, and third parties, although applying security and privacy policies in a manner that does not lead to dissatisfaction which is a complex affair (Umar, Singh, and Sanober 2016).

4.6. Defence against threats

The SGs have inherent vulnerabilities against which it must be protected. This can be achieved by building an effective, layered defence system for the protection of the SG infrastructure (Umar, Singh, and Sanober 2016). This defence or protection against threats or vulnerabilities gives the network segmentation and access control to defend against denial-of-service (DoS). Technologies used include firewall, virtual private network (VPN), intrusion prevention system (IPS) (Nasir 2021). This leads to extra investment in technology and resources adding to system costs (Kumaran, Singaravelu, and Vivekananda 2013).

4.7. Physical security

SG systems have thousands or millions of widely spread remote points and networks. This the challenge of policing or physical protection from theft, sabotage and illegal or unauthorised access (Umar, Singh, and Sanober 2016). Therefore, physical protection is a real challenge for SGs. Additionally, the wider geographical dispersion of the many assets and systems makes it difficult to access all of the terminals for both maintenance and protection (Asia Pacific Economic Cooperation 2011; Kumaran, Singaravelu, and Vivekananda 2013)

4.8. Connectivity challenges

This refers to the communications connectivity and interchange within the SG infrastructure and between users or stakeholders (Umar, Singh, and Sanober 2016). The current trend in communication technology also implies a transition from analogue to digital communication and towards an Internet-like distributed environment where large number of devices are interconnected. Not all regions, devices or users have access to modern and effective internet and communication infrastructure especially where the services a publicly accesses and not limited to the grid system (Kumaran, Singaravelu, and Vivekananda 2013; Umar, Singh, and Sanober 2016)

5. Sustainability and sustainable development

SGs have been identified as key building blocks for the transition to future sustainable energy with less greenhouse gas emissions and better quality of energy services. It has been established that smart energy systems are not just an issue of technological development but should also consider the operation and impact of grids in which the energy technologies are applied or used. The underlying physical energy network is a network of stakeholders, who include various consumers, electricity producers, and power grid operators, with vested and often competing or conflicting interests (Amjad, Ghassem, and Josep 2016). This requires regulation to define or guide the relationship between these competing stakeholders. SG applications should adapt to the local grid characteristics like., population density, diversity, and consumption patterns. SGs are quick to adapt and influence the operation, policy direction, and regulatory mechanisms. Global warming concerns, serious energy shortage and sustainable development targets are today urgent requirements globally. Integrating SG technologies, increasing the use of sustainable energy resources and low-carbon emissions from the power sector, is important route to sustainable global development (Amjad, Ghassem, and Josep 2016; Hu et al. 2014).

5.1. Sustainability

Although the concept of sustainability is new in the energy sector, the concept the movement has roots in social justice, internationalism, conservationism and other past movements that cumulatively led to the call ‘sustainable development of the twentieth century (McGill University). Sustainability constitutes a promise of social evolution to achieve an equitable and wealthy world for all, where environment and cultural achievements are preserved for future generations (Defranza 2020). Organisations should seek to attain sustainability; they should carry out their operations and undertakings sustainably, in a concept referred to as organisational sustainability. Acceptability constitutes the minimum criteria for sustainability and hence for, policies, measures or strategies must be accepted by stakeholders (Jefferson 2020). In the energy sector, sustainability demands that power or energy producers must grow their social, economic and environmental capital base while at the same time add value on sin the political and environmental arena. Therefore, long-term sustainability demands satisfaction of social, economic, and environmental dimensions of sustainability in energy generation, supply, and consumption (Kabeyi and Olanrewaju 2022q; Kabeyi and Olanrewaju 2022x; Kabeyi and Olanweraju 2022i).

5.2. Sustainability in electricity generation and role of SGs

The threat of global coal, natural and related consequences have led to significant increase in demand for alternative energy solutions to the continued reliance conventional energy sources mainly in the form of coal, natural gas, oil and nuclear energy (International Energy Agency; Kabeyi 2019b; Kabeyi and Olanrewaju 2022f). Energy projects have several long-term non-financial benefits like increased productivity, attraction of expertise and its retention, better health, and higher quality of products and which are key sustainability concerns (Kabeyi and Olanrewaju 2022n; Kabeyi and Olanweraju 2022i; Wanga et al. 2020). Therefore, sustainability is an important dimension in the energy transition.

Sustainability is concerned with acceptable long-term conditions, in almost all fields including project management (Harrington 2016; Kabeyi and Oludolapo 2021a). In projects, the scope, time and resource use efficiency and economy are key to sustainable development. Sustainability in power generation requires policy makers and planners as well as operations managers to be aware of the impact of their activities on the environment and society. Power projects s should integrate sustainability practices and guide organisations towards sustainability like waste minimisation, reduced emissions, reduced cost, high efficiency and conformance to standards all which can be significantly enhanced by use of SGs (Kabeyi and Oludolapo 2020a; Tharpe 2012). A sustainable focus recognises the interdependence between companies and the broader society and encompasses aspects like human rights, labour issues, environment, and ethical aspects which can be integrated in SG development strategy (Kabeyi 2018; Kabeyi 2019c; Kabeyi 2020a; Kabeyi 2020d).

5.3. Energy for sustainable development and role of smart grids

The increased uptake of renewable energy resources will help mitigate climate change since they are considered clean with less waste and less environmental impacts unlike the conventional and non-renewable energy sources, which gives them an important role in the energy transition (Kabeyi and Olanrewaju 2021g; Kabeyi and Olanrewaju 2022n; Rathor and Saxena 2020). The main challenge facing the consumption of renewable sources of energy is the variability and intermittent of wind and solar which hold the key to the energy transition. For renewable sources like biomass, the consumption should be sustainable for them to remain renewable (Owusu and Asumadu-Sarkodie 2016). The evaluation of energy sustainability takes into account factors like economic sustainability, institutional sustainability, technological sustainability and development, energy security, environmental impacts, and prevailing state of the energy market (Kabeyi 2012; Wanga et al. 2020). According to (Kabeyi and Olanrewaju 2021b; Kabeyi and Olanrewaju 2022g; Vijayapriya and Kothari 2011) a sustainable energy considers the limits of resource availability and supply as well as environmental and social impacts like GHG emissions and other pollutants as well as the economic and social value to the society like jobs, clean power and energy security (Vijayapriya and Kothari 2011). Development and climate change mitigation are now an integral part of electricity planning, analysis and policy making globally, which gets a lot of support from the SG infrastructure and functionalities. Management of energy mix and efficiency are key in managing emissions and energy costs (Kabeyi 2019c; Kabeyi 2020d; Kabeyi 2020e). To meet the long-term climate targets set by the Paris agreement requires urgent tackling energy-related greenhouse gas emissions by scaling up the contribution to grid electricity system (Dufour; Kabeyi and Olanrewaju 2023).

Increased decentralisation of generation which can further be enabled by the advances in SG technology and adoption leads to benefits like direct access to renewable energy, reduced emissions, energy security, and rural development. It is also important to note that countries are endowed differently with energy resources making sharing of resources an important sustainability strategy (Kabeyi and Oludolapo 2020d; Kabeyi and Oludolapo 2020e). As an example, France with its low carbon nuclear electricity dominated grid can share with neighbours heavily relying on fossil fuels, Ethiopia and Sweden have e huge hydro power potential which dominates their respective national grid power that can be shared regionally to de-carbonisation of other countries grids (Kabeyi and Olanrewaju 2022b; Kabeyi and Olanrewaju 2022d; Kabeyi and Olanrewaju 2022w). A sustainable energy strategy requires integration of the onsite power plants, regional grids, and diversified conventional grid components, and the operation of such diversified resources can be made efficiently feasible using interconnectors and SGs to provide the necessary infrastructure and capability (Hart 2008; Jefferson 2020).

6. Enhancing sustainability in electricity generation

Sustainable energy development is defined by the International Atomic Energy Agency (IAEA) as ‘the provision of adequate energy services at affordable cost in a secure and environmentally benign manner, in conformity with social and economic development needs’. In the year 2001, the international Energy Agency (IEA) defined sustainable energy development (SED) as ‘development that lasts and that is supported by an economically profitable, socially responsive and environmentally responsible energy sector with a global, long-term vision’ (Davidsdottir 2012).

A sustainable global energy and electricity transition calls for increased use of renewable energy sources solar and wind, nuclear energy which is a nonrenewable but low carbon source, electrification of transport and industrial thermal processes, use of bioenergy, and waste to energy conversion, shift from high carbon coal and petroleum to cleaner natural. Gas and biomethane (Davidsdottir and Axelsson 2022)

Decarbonisation of grid electricity is a leading option in the effort to minimise greenhouse gas emission and related consequence of climate change (Conejo, Morales, and Baringo 2010). Both technical and non-technical measures should be adopted to ensure that energy systems support or enhance sustainable development (Kabeyi and Oludolapo 2020a). The main sustainability challenges increasing energy access, affordable, reliability, and adequate energy supplies while addressing environmental impacts at all levels (Conejo, Morales, and Baringo 2010; Jefferson 2020). The policies needed to support sustainable development include

1. Supply affordable and adequate energy and electricity to unserved or underserved areas and populations

2. Increase the contribution of renewable energy sources in power generation

3. Adopt new and modern technologies in generation, supply, and consumption of electricity mission

4. Optimisation of operations in grid power systems.

Many of the stated objectives can be achieved with the right policies, prices, and regulations in place. It is important for energy markets to protect important public benefits, through programs, policies, and regulations to achieve policy objectives. Although strategies to achieve sustainable energy systems look straightforward, wider acknowledgement of the challenges and stronger commitment to specific policies, strategies, and technologies is critical (Kumaran, Singaravelu, and Vivekananda 2013; Nguyen et al. 2020; Vijayapriya and Kothari 2011). The challenges facing development sustainable energy require that governments put in place measures that promote investment and consumption of renewable energy sources which ultimately need one to use technology and infrastructure like SGs (Kabeyi 2022; US Department of Energy 2018).

SGs can help in the reduction of carbon emissions in the in-power generation and supply by connecting more renewable energy sources especially variable renewables like wind and solar, and reduction in greenhouse gas emissions through efficient resource use. Network operators must minimise their carbon footprint in their operations and measures used to achieve these include reducing callouts with and associated vehicle fuel usage, reduce and leakage of SF₆ in gas-insulated switchgear besides reducing operation and maintenance costs. This is achieved by provision of faster-automated services for operations like real-time automated meter reading, automated outage management done remotely with limited site visits by technicians and engineers(Bayliss and Hardy 2012; Giaouris et al. 2015).

7. Results and discussion

The electricity grid has to continuously and consistently progress so that it can meet the growing needs in the electricity sector and to replace old-pattern power generation with renewable generation with electricity provisions from green energy resources (Kabeyi and Olanrewaju 2022e; Kabeyi and Olanweraju 2022i; Saumen, Alok Kumar, and Pradip Kumar 2021). The SG is modernising power systems towards high consistency, higher efficiency, reduction in costs and power losses while incorporating variable renewable energy sources to the grid. The electricity market is characterised by changing consumer needs and trends, new industrial invention and growing demand for renewable energy resources for power generation (Kabeyi and Olanrewaju 2022d). These changes and advances in the electricity and general energy markets call for modernisation of the electricity to cope with the changing markets. The. SG has emerged as an ultimate answer to the ongoing technological and electricity market reforms occurring in power generation, the transmission and distribution that requires increased application of sensors, advanced two-way communication computers (Kabeyi and Oludolapo 2020a; Saumen, Alok Kumar, and Pradip Kumar 2021).

The SG system is a complex and multi-disciplinary, and relatively under-researched concept. SGs implement smart contracts which are integrated with smart energy meters hence allowing tracking of energy profiles against available energy flexibility transactions as well as decentralised settlement of participant wallets (Antal 2021). The study demonstrated the significance of block chain and smart contract technology which is growing rapidly with many companies and industries adopting the technology. The adoption of block chain and smart contract technology will bring significant benefits to both consumers and prosumer in a decentralised an SG (Tsao and Vu 2021).

The use of SGs can enable up to 100% uptake of renewable energy in the local MGs. When used in MG application, SGs can make it possible to realise up to net (Kabeyi and Olanrewaju 2021d) zero the exchange between a local MG and utility grid even when we have high variability and intermittence of the renewable sources of energy particularly wind and solar.

By facilitating efficient monitoring and feedback between consumers, producers, the utility and other stakeholders within the grid system, energy costs and unnecessary consumption and overloads can be avoided and achieve energy balance at MG as a benefit of enhanced monitoring of energy flows, electricity demand and power generation, power generation enabling a high level of energy flexibility (Kabeyi 2018; Kabeyi and Olanrewaju 2021a). Through provision of optimising capacity, use of SGs facilitates cost reduction of the cost of energy or electricity.

7.1. Technologies in smart grids

SGs make use of a broad range of technologies and appliances. They include smart meters, SCADA, and FACTS while several technologies are still in the early stages of development like PMU and V2G technologies. Of the technologies used in SGs, some are specific to electricity systems, while others cut across other energy systems, but others are common ICT applications in other sectors. The various technologies in SGs are summarised in Table 2.

Table 2. Technologies in SGs.

	Area of technology	Hardware	Systems and software	Network deployment
1	Wide area monitoring and control	PMUs and other sensor equipment	SCADA, WAMS, WAAPCA, and WASA	Transmission
2	ICT integration and office computers	Communication equipment (power line carrier, WiMAX, LTE, RF mesh network, cellular), routers, relays, switches gateway, computers (servers)	Enterprise resource planning software, customer information system	Transmission and distribution
3	Renewable,distributed and conventional generation integration	Power conditioning equipment for bulk power and grid support, communication and control hardware for generation and enabling storage technology	EMS, DMS, SCADA, GIS	Transmission and distribution
4	Transmission enhancement	Superconductors, Flexible alternating current transmission system (FACTS), High-voltage direct current transmission system (HVDC)	Network stability analysis, automatic recovery systems	Transmission
5	Distribution grid management DERs	Automated re-closers, switches, and capacitors, remote-controlled DG and storage, transformer sensors, wire and cable sensors	GIS, DMS, outage management system (OMS), workforce management system (WMS	Distribution
6	Advanced metering infrastructure (Smart metering)	Smart meter, in-home displays, servers, relays	MDMS	Distribution and (transmission)
7	Electric transportation charging	Charging infrastructure, batteries, inverters	Energy billing, smart charging G2V and discharging V2G methodologies	Distribution
8	Customer-side systems and demand response	Smart appliances, routers, in-home display, building automation systems, thermal accumulators, smart thermostat	Energy dashboards, EMSs, energy applications for smart phones and tablets	Distribution and (transmission)

From Table 2, it is noted that SGs function because of the various technologies cutting across power, electronics, communication, and computer technology.

The SGs incorporate technologies that facilitate real-time monitoring and control of power making it possible for grid operators to introduce different tariff structures that enable demand-side response and management (Kappagantu, Daniel, and Suresh 2016). Power consumers are also provided with trading or business opportunities created by decentralisation of generation through energy savings and revenue by trading over SG block chain-driven decentralisation and flexibility made possible by digitalisation like smart metering and use of flexibility tokens. Consumers can generate for self-consumption when prices are high and sell excess when prices are favourable in a two-way trading over the SG. Figure 8 shows diagrammatically the various functions of an SG (Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022d).

Figure 8. The main functions of the SG.

From Figure 8, the main functions of SGs are summarised as the integration of renewable energy, smart appliances, DG and related storage, electric car charging infrastructure as well as V2G facilities, transmission, and distribution automation functions, energy efficiency improvement among others.

Although SGs provide better efficiency in monitoring power consumption, manage peak demand by directing power supply to manage peak power needs and enhance efficiency in transmission and distribution, they open an opportunity for information security breaches and other types of security-related risks like meter manipulation, high-impact attacks on critical infrastructure that can lead to grid failure (Kabeyi and Olanrewaju 2022d).

7.2. SG architecture versus conventional power systems

The key domains of power systems are power generation, transmission, and distribution while the main elements of the traditional power generation scheme are a synchronous generator in a three-phase electrical energy generated in centralised power stations. On the other hand, distributed energy systems are interfaced with power electronic devices needed to meet varying load requirements of users (Panda and Das 2021).

For SGs, there is a need for a communication layer to interoperate between manual control and multiple sensors, automatic controllers, and actuators in the physical layer of the grid. Communication in electricity systems ought to be robust to meet the latency and overcome bandwidth challenges. Commonly used communication technologies are IEEE-specified Zigbee, WiMAX and wireless LAN technologies, GSM 3G/4G cellular, and DASH7 (Panda and Das 2021). The power line communication (PLC) is the most common standard communication in power systems and SGs applied low, medium, and high voltage electricity networks. SGs need a robust communication network for the successful operation of wireless sensor networks (WSNs). Data exchange and storage for SG protection and control applications is facilitated by the information layer of SG. The SG automation architecture can be provided by standards – IEC 61850 and IEC 61499 which support multi-agent intelligence and DA simulation while software like SimPowerSystems in Matlab can be applied to validate custom-designed user datagram protocol (UDP) socket. Market algorithms can be applied to maintain a balance between demand and supply where in some typical applications use Power Matcher software is applied (Panda and Das 2021). The application of multiple gateways at customer levels can define security architecture that provides communication and cryptographic abilities amongst themselves and external entities whose benefit is to preserve privacy in the network. Homomorphic encryption can be used for DR schemes (Panda and Das 2021).

The main components of the SG architecture are summarised in Table 3.

Table 3. Summary of architecture (UNECE 2016).

	Element s	Construction	Applications
1	SCADA	This is an EHV transmission network (110 kV and above) that is traditionally smart or intelligent equipped with automation and real-time communication systems for system operations.	SCADA operates by collecting information related to grid operation from various sensors located at various points and sending data to the master computer for real time analysis. SCADA with the EMS monitor and control of power flows in real time at dispatch centres or at LC centres of EHV
2	The Energy Management System	EMS is used by grid operators as a tool for monitoring, controlling and optimisation of power generation and transmission systems. It facilitates real time network and contingency analysis.	The EMS enables real-time functions which enable the plant operator to monitor, analyse and control power generation functions on a real time basis. It enables automatic generation control, sets economic dispatch, and directs the dispatcher to set economic base point for the generator units selected, monitoring of the reserve, and establishing spinning reserve, regulating reserve and operating reserve levels.
3	Wide Area Monitoring System (WAMS)	The system deploys PMUs used for faster and more accurate measurement of the grid equipment. Additionally, SCADA data does not have timestamps, while PMU data is accurate time stamped. Operationally SCADA works like an X-Ray, but PMU Data is like an MRI scan of the electricity grid	This requires a fast communication system to handle these huge amounts of data from the PMUs. For real-time wide area monitoring applications, the latency requirements are high in the range of 100 ms to 5 s. The main differences in functionalities between PMUs and SCADA is that in SCADA data is collected in 1-5 s, but PMU data is captured in milliseconds.
4	Distribution automation (DA)	The DA involves computerised control strategies used to upgrade implementation of energy dispersion. The lattice physically recognises and breaks down the energy system physically and remotely enacts gadgets or dispatch an expert to intervene.	The distribution automation (DA) enables specific gadgets to detect operational states of surrounding lattice then influence necessary changes to streamline operation making the network more proficient and solid. The DA facilitates change of controls to suit fluctuation, control inclining and bi-directional power streams.
5	Substation Automation and substation automation systems	Through the automation of substations, the equipment or components of substations are made digital (or numeric) with related communication systems to facilitate remote operation.	Substation automation cuts down interruptions and downtime caused by equipment failures, strikes from lightning, accidents and natural catastrophes, surges or power disturbances and substation outages. Substations automation enables the utility company to remotely monitor, control, coordinate and operate power distribution components at substations
6	AMI or Smart Metering system	comprises of equipment or devices like Smart Meters, DCUs also referred to as gateways, routers or access points, Meter MDMS, HAN, HES	The smart meter electronically records electricity consumption normally on hourly intervals or less and communicates with the utility on regular basis for monitoring and billing. They facilitate a two-way communication between computer systems/computers at the utility control centres and the meter the consumer point
7	Block Chain Technology infrastructure	The block chain technology is made up of distributed information and communication technology	It supports decentralised structure of local energy markets and facilitate direct interaction between SG users

From Table 3, it is noted that the main elements of the SG architecture and operations are the SCADA, Block Chain Technology infrastructure, AMI also called Smart Metering system, Distribution automation (DA), Substation Automation, Wide Area Monitoring System (WAMS) and the EMS. Other components of the SG architecture are household appliances, energy sources, Smart Meters, the Power Utility Centres. The smart meter contains a microcontroller that has memory, digital ports, timers, real-time, and serial two-way communication facilities. Smart meters join house or user devices and the external systems to the utility monitoring and control systems.

7.3. Characteristics of SGs

SGs integrate electricity networks consisting of transmission and distribution systems and interfaces with generation, storage, and end users. The SGs are evolving sets of modern technology that can be deployed globally guided by local commercial attractiveness, legal and regulatory framework, technology compatibility, and investment frameworks (Edvard 2022; Jackson 2014). The main characteristics of SGs which influence their application are as follows:

1. SGs have the ability to integrate different energy sources in the distributed energy system in a way that optimises power and delivered effectively to the grid (Broman and Robert 2015; McGranaghan and Goodman 2005).

2. The SG system facilitates quick electricity DR that can create peak load sharing, load profile shaping with high degree of effective and reliable control and maintenance (Conejo, Morales, and Baringo 2010). Which effectively increases the utility and control of distribution system equipment, improves DR, leading to better power system stability (Jackson 2014).

3. The system applies communication systems like wireless, wired communication technologies and end-to-end communication management to provide integrated communication system through DAS and other technologies (Kumaran, Singaravelu, and Vivekananda 2013; McGranaghan and Goodman 2005), to coordinate and integrate communication, new metering, system controls, and customer engagement technologies and strategies, by leveraging technologies and programs to realise across the entire power utility system (Parhizi et al. 2015).

4. The SG system uses AMI for communication between the utility company, consumers, and operators (Hart 2008). Individual equipment and customers are metered throughout the distribution system as well as transformers, switches, capacitor banks, voltage regulators, and other equipment. Information from these equipments and customers is relayed to the utility in a typical two-way communication (Jackson 2014).

5. Applies cyber-secured communication like data supervisory control and EMS (Kumaran, Singaravelu, and Vivekananda 2013; Prasad 2014).

6. The SG enables demand profile shaping, and peak load shaving to optimise power generation cost and increase consumer utility through real-time pricing technologies (Kumaran, Singaravelu, and Vivekananda 2013).

7. The SGs facilitate greenhouse gas emission minimisation by efficient integration of variable renewable energy sources and variable loads like electric cars compared to the conventional grid system (Kumaran, Singaravelu, and Vivekananda 2013; Nguyen et al. 2020).

8. Enables active participation of stakeholders like the customer which enables customers to provide electricity and additionally respond actively to signals from the utility meant to reduce electricity during peak hours and during times of distress for the utility (Jackson 2014).

9. The SG has the infrastructure to support a two way communication as well as the flow of electricity from the utility to the customers which converts electricity consumers to prosumers (Edvard 2022)

7.4. Conventional grids versus SGs

The main differences between SGs and convention grids are summarised in Table 4.

Table 4. Differences between conventional grids and SGs.

	Basis	Conventional grids	Smart grids
1	Communication	One way communication	Two-way communication
2	Power generation	Centralised power generation	Distributed and central power generation
3	Network connection	Radial network	Interconnected network
4	Sensors	Uses basic sensors	Uses Multiple advanced sensors
5	Mode of operation	Manual or analogue operation	Digital operation
6	Control and monitoring	Limited manual monitoring and control	Wide range Automatic monitoring and control
7	Security and privacy	Limited security and privacy concerns	Serious security and privacy issues

From Table 4, it is noted that there are significant differences between the SG and the conventional grid. The SG is equipped with automatic monitoring and control capabilities making it a complex intelligent system.

7.5. Stakeholders in SGs

The SG system is composed of many organisations that cumulatively constitute a recognised area of institutional life. The SG operating environment has got several stakeholders who are interrelated. As per the SGIP and NIST algorithm or methodology which is used for planning or organising the various SG networks interconnections, there are seven domains of the SG that represent the seven main stakeholders. They are service providers, generation, customers, transmission, distribution, the operator, and the market (Moreno Escobar et al. 2021).

The stakeholders and their role in an SG system are summarised below (Majeed Butt, Zulqarnain, and Majeed Butt 2021). Table 5 is a summary of the various SG stakeholders and their functional roles.

Table 5. Stakeholders and role in the SG system.

	Stakeholder	Role
1	Customers	Electricity is consumed by consumers. It may be domestic, commercial, or industrial
2	Operations	Operations related to power systems are performed. It comprises regulatory authorities or management responsible for movement of electricity
3	Markets	Grid assets are used by stakeholders. Both operators and consumers are playing role as market.
4	Generations	Electricity is generated. Generation companies in bulk quantity of electricity are involved as player.
5	Transmissions	Electricity is transmitted. Companies or player responsible for transmission of generated electricity for distribution.
6	Distributions	Electricity is distributed to end consumers and monitored. They include distributor of electricity form and to customers.
7	Service providers	They provide support services to all the power system stakeholders like internet and communication services. providers

Table 5 summarises the main stakeholders in the SG system namely, markets, customers, generations or power plants, transmission, distributions, and various service providers together with their functions in the SG system. The positional relationship between SG stakeholders is presented in Figure 9.

Figure 9. The SG stakeholders.

From Figure 9, it is noted that all the stakeholders in a power system are directly or indirectly related to one another through support systems provided by SGs like two-way communication.

7.6. Benefits of SGs

SG facilitates power generation decentralisation and intelligent management of generation, transmission, and distribution resources. An SG is an electricity network allowing devices to communicate between suppliers to consumers, allowing them to manage demand, protect the distribution network, save energy, and reduce cost. The system has demonstrated ability and competence to meet required electricity availability, supply reliability, power quality, as well as economic and efficient operation, enhanced safety, higher security, and enhanced solution to the challenge of global greenhouse emissions and global warming and hence a better environment and sustainable future (Kappagantu, Daniel, and Suresh 2016). By investing in SGs, provides an opportunity to maximise the return on investment (ROI) by using SGs to analyse important data and automate finding operations which can increase revenue and minimise expenditure (Kabeyi and Olanrewaju 2022d).

There are several specific benefits for the use of SGs. According to Vijayapriya and Kothari (2011), the benefits of SGs are:

1. The SG system enables seamless connection and operation of different generators in terms of size and technologies.

2. Reduces maintenance expenditure through automatic reporting and tracking as opposed to manual or physical tracking which is expensive and inefficient.

3. The use of SGs reduces electricity theft through remote monitoring of meters and any tempering attempt raises an alert signal. Utilities are also immediately notified if deviations in power consumption are noted prompting swift action.

4. They enable automatic load balancing which reduces the risks of equipment failures as opposed to manual adjustments. SGs rely on genetic algorithms to review consumption patterns and manage loads which reduces stress on electrical equipment, especially during peak times.

5. The SGs enable higher power transmission efficiency since they have ability to regulate electrical transmissions by relying on intelligent technologies to mitigate electrical losses in distribution which improves the efficiency of electrical transmission, for the benefit of all stakeholders.

6. SGs improve power system stability, security, significantly.

7. SGs prevent transmission oscillations, overload, and resultant blackouts by facilitating automatic loading and re-routing of electricity any time an equipment fails.

8. SGs help consumers to save on energy cost by providing time information on demand and price to enable them to plan their consumption.

9. SGs facilitate better integration of renewable energy by enabling accurate planning through timely data on both weather and demand as well as increased flexibility which enables the great to absorb more variable sources of power and loads.

10. Better facilitate the connection and operation of generators of all sizes and technologies seamlessly to a common platform.

11. SGs optimise grid operation which improves overall reliability and stability of the power system by allowing consumers to be an active participant in the optimisation of the grid.

12. SGs facilitate accurate and timely planning and action by availing real time data and information to create a stable, efficient, and cost-effective system.

13. The use of SGs facilitates reduction in the environmental impact of power systems through optimum loading of generation systems.

14. Improves reliability, quality, and security of the electricity supply system.

15. SGs help improve the quality and performance of energy products and services by fostering market integration and harmonious stakeholder relationship and operation.

16. SGs convert electricity consumers to prosumers who do both generation and supply of grid power based on variable pricing and two-way flow of electricity and data.

17. By combining or integrating weather and demand forecasts, more accurate generation planning, and dispatch can be done.

18. They provide resilience to system attacks, and disaster in terms of enhanced ability to react to emergencies by isolating and re-routing power flow including self-healing ability which reduces downtime and outages.

The SG system offers solutions to several challenges facing power generation, transmission, distribution, and power system control by providing necessary capacity and infrastructure to enable efficient use of variable renewables and variable loads while at the same time guarantee a stable and reliable power supply and minimise fossil fuels. Through these functions and capabilities, the SGs provide an avenue for sustainable electricity generation and supply as can be summarised in Figure 10.

From Figure 10, it is observed that the SG provides a conducive environment that will facilitate sustainable energy and electricity transition though features and technologies like the sensors, information system, power electronics, communication, energy security, storage infrastructure, DR capability and facilities, and seamless coordination of a mix of central and decentralised power generation and distribution.

Figure 10. SG environment and impact on sustainability.

7.7. Summary of features and capability of SGs (Majeed Butt, Zulqarnain, and Majeed Butt 2021)

The SG system has several capabilities that enables it to function. These capabilities are summarised in Table 6.

From Table 6, it is observed that the SG has several capabilities like ability to seamlessly integrate variable renewables and optimise grid operations which gives it a significant role to place in the energy transition from fossil fuel based to low carbon and renewable energy resources.

Table 6. Capabilities and benefits of SGs.

	Capability/function	Sustainability impact
1	Seamless connection of generators of different sizes, features, sources of energy	Prevents power loss and maximises use of variable loads and power sources
2	Enhances reliability, security, and stability of supply	Guarantees sustainable electricity supply
3	Enable automatic loading and re-routing of electricity whenever equipment fails	Avoids unnecessary power supply losses and reduces downtown hence high supply security and reliability.
4	Prevent transmission oscillations and overload which often cause blackouts	Reliability of power supply and more absorption of variable loads like electric cars and variable supply like wind and solar power.
5	They provide real-time information on consumption to stakeholders.	Facilitates social sustainability and technology acceptance which is a sustainability requirement.
6	Enable consumers to adjust in time and quantity of energy usage	This will reduce overload on generation facilities, improve efficiency and hence avoid wasteful generation and consumption.
7	Facilitate higher integration of renewable energy	Facilitates fossil fuel substitution in power generation.
8	Convert consumers to prosumers who produce and sell their own	Provides a revenue source for consumers, motivation to consume less and generate more and enable economic sustainability of power systems.
9	Optimise overall grid operations from generation to consumption.	This will reduce wastes and pollution, avoid unnecessary generation and consumption as well as avoid unnecessary investment and costs in the power system.

7.8. Applications of SGs

Energy sustainability and transformation is a global challenge which faces issues like wide demand–supply gap, overreliance on fossil fuels, and low penetration of variable renewables. The SG has been identified as a potential solution in the smooth transition from traditional to modern smart energy systems (Bhattarai et al. 2022). They facilitate the integration of all forms of electricity generation across the grid coverage. SGs can be used to optimise energy consumption because of their ability to integrate sources, direct and coordinate operations throughout the entire energy supply chain. SGs can enable electricity consumers to realise financial savings and income through measures like flattening peaks and conversion of consumers to prosumers who not only consume power but also supply power in a two-way power flow process in an SG (Kabeyi and Olanrewaju 2022a; Kabeyi and Olanrewaju 2022d; Kabeyi and Oludolapo 2020a). As a result, SGs offer opportunities for new, energy-related services while making energy systems more dynamic and improving security of electricity supply. Therefore, SGs have an important role to play in the global energy transition to renewable and low-carbon energy sources (Kabeyi and Olanrewaju 2022b; Kabeyi and Olanrewaju 2022d; Smale, van Vliet, and Spaargaren 2017).

There are various applications and features of SGs which significantly make them superior compared to the traditional grid. These are summarised in Table 7.

Table 7. Applications of SGs.

	Function	Application	Impact
1	NET metering	Electricity imports and export	Turns consumers of electricity to prosumers who are keen to be net exporters not importers
2	Time of Use (TOU) Metering	Enables variable pricing of power	Facilitates demand side management by demand shifting
3	Peak load shaving	Demand shifting which reduces maximum demand and cost.	SGs create flexibility and demand shifting leading to load management, peak shaving and energy saving by moving to off peak hours. The Peak load benefits all consumers and the utility operators by avoiding overloading of the system
4	Power quality improvement	Reliability and quality improvement. SGs are equipped with APFC devices and modern communication functions for regular reporting to the utility control center	The grid intelligence, resilience, flexibility, and adaptability are enhanced by use of SGs. SGs use APFC devices and active filters to improve the power factor and power quality.
5	Outage Management through self-healing and early detection	SG are equipped with Outage management system (OMS). The DTMS systems is equipped with oil sensors, palm sensors, CT and PT. which enable DTMS to detect and correct faults	The outage management system enhances the reliability of the power systems by application of the grid smartness for operational benefits like power restoration, reliable and cost-effective services with less manpower and hence costs
6	Loss detection which ensures timely action and low outage	Smart meters collect, compute, store, and transfer energy data to control center at constant intervals. Power losses can be determined by comparing the energy data at different nodes and DT terminals	This enables quick measures to restore power to consumers immediately power loss is identified.
7	Improves power system reliability	This is achieved in SG by the ability to detect faults and self-healing potential of the system. SG can monitor all information and data and can establish system reliability. SGs make use of technologies like Dynamic Stochastic Optimal Power Flow (DSOPF) which make it possible to estimate and optimise	Facilitates efficient monitoring of hybrid generation and management of the grid remotely which improves power reliability. power flow in the system. Therefore, SGs can improve system reliability through enhanced metering and communication
8	Demand Side Management through participation of consumers	DR is the ability by consumers to modify energy consuming models in response to variations made possible by the two-way communication ability of SGs.	Enable a more economical use of grid power and hence higher efficiency and reduced peak time stress by shifting load and self-generation. DR enables the distribution system to schedule resources based on requirement. The system also provides financial incentives by scheduling consumer needs.
9	Decentralised power generation.	Decentralised generation uses different local energy sources to meet the demand of local electricity demand by integrating various forms of locally available supplies including energy storage.	Leads to more use of renewable sources and hence emissions. DG also helps to address twin challenges of generation fluctuations and huge land requirements associated with wind and solar energy resources
10	MGs which are more resilient	MGs are small and autonomous subsets of the main electricity grid, which help reinforce the self-healing characteristics of SGs and support decentralised generation	MGs supply energy obtained by means of DERs to nearby consumers. SG components can be used to fix issues facing traditional MGs thus transforming them into smart MGs by introducing smart technologies
11	Integration of Renewable Resources	Substitution of fossil fuel sources	More reliance on local resources hence lore energy security
12	IoT	The IoT enables access to information any time wherever you are connecting devices through real-time information	Helps to achieve optimal control and maintenance of home appliances by integrating recent and modern Information and Communication technologies (ICT) and energy technologies in the housing environment. These reduces energy cost and wasteful use of energy.
14	Smart charging Electrification of transport hence reduced emissions	Electric vehicles use chemical energy stored batteries that can be recharged and used in vehicle propulsion and supply of power to the grid when prices are favourable. Reduces emissions from transport sector which is about 14% of global GHG emissions from anthropogenic sources.	Smart charging can be centrally done through aggregators or can be decentralised using decentralised control structures. Smart charging using both centralised and decentralised systems can effectively reduce energy costs and prevent the overloading of grid components by shifting peak demand.
15	Reduce Transmission & Distribution Losses hence high efficiency	Decentralisation of generation at sites close to consumers hence less transmission and distribution costs and losses.	Increased use of decentralised resources increases energy security and more use of renewable sources in power generation, increases access and reduces cost of power.
17	Development of smart cities and streetlight automation	Smartness of a city refers to the desire to improve the quality of life in a city and living standards of the city residents in terms (ICT). Intelligent application of SG is a key requirement for the establishment of smart cities.	Smart cities have been identified as the ultimate solution to complex challenges facing urban centres like energy supply, emissions, water supply, traffic congestion. Cities will account for about 70% of global population by 2050.
18	Grid Integrated Energy Storage	Seamless integration of energy storage to the grid	Optimum use of energy storage leading to increased uptake of VREs of energy.
19	V2X technologies	SGs will enhance electrification of transport creating opportunities for related sustainable technologies like V2V, V2H, V2G	Therefore, SG technology deployment will enhance the operation and control of electric vehicles making them important energy transition facility
20	Rural electrification	The SG also provides significant opportunities for alleviation of rural electrification through development of smart MGs based on renewable energy sources	Through SGs, significant opportunities for alleviation of rural electrification challenges are addressed by providing infrastructure for wider exploitation of renewable energy sources like biomass, solar PV, and wind, through active engagement of individuals, private business and connecting them to the national grid

Table 7 summarises various applications of SGs which improve the sustainability of grid electricity. This is realised by increasing system efficiency, increased uptake of renewable sources of energy, increased energy security by enhanced decentralised generation utilising local energy resources. By two-way communication and flow of power, consumers are converted to prosumers. Improved stakeholder interaction due to active participation using two-way communication increases social sustainability of energy systems.

SGs use semiconductor-based FACTS and RACDS devices, replace mechanically driven devices making the grid responsive in case of faults and reduce electricity losses. The SG also provides significant opportunities for alleviation of rural electrification through the development of MGs based on renewable energy sources like biomass, solar PV, and wind, through active engagement of individuals, private business and connecting them to the national grid (Bhattarai et al. 2022). Additionally, through scheduled charging of electric vehicles, the SG will encourage people to embrace EV technology leading to emissions from the transport sector and significant reduction in dependence on fossil fuel and transforming the transport sector into a partaker in DR management (Bhattarai et al. 2022; Kabeyi and Olanrewaju 2022d).

The SG functionality has a very critical role in the delivery of electricity to consumers in a participatory manner by many players (International Energy Agency 2011; Skopik and Smith 2015). These are achieved through the following function.

1. Monitoring of distribution grids

The primary objective of SGs is to increase the transparency in the operation of the distribution grid through improvement in the monitoring capabilities. According to International Energy Agency (2011), the traditional grid needs extra technologies in the distribution domain that are required for deployment of SGs. They include automated re-closers, switches, remote-controlled DG and energy storage, sensors for cables and cables and transformer. The sensors needed can be dedicated grid sensors especially for transformer substations and at critical locations within the network. Smart energy meters can also be used to reveal essential data for grid operation, control, and planning. The SG ICT has the main duty of transporting grid monitoring data across the power grid (Skopik and Smith 2015).

• ii.) Provision of ancillary services for users

Ancillary service are services provided by power network participants particularly the large power plants required for safe and reliable operation of the power system. These services include frequency control, reactive power control, and voltage regulation . With SGs, significant generation is shifting to the distribution grids hence connected generators will increasingly be involved in provision of the ancillary services. Additionally, the power customers will also provide ancillary services in the form of active management of load flexibility. Virtual Power Plants or aggregators can combine small units of generators, loads, storages and generate ancillary services from their resources which increases power system reliability and efficiency. The communication and management between individual units and the aggregators and ancillary service providers to consumers is another important application for SG ICT (International Energy Agency 2011; Skopik and Smith 2015).

• iii.) Advanced control of distribution grids

Technical barriers to grid integration of variable renewable energy sources have been a major driver for SG deployment. The main technical barrier is increased in line voltage levels from distributed generators (Skopik and Smith 2015). The approaches used to solve the problem are:

1. Grid reinforcement involves the building of new lines or transformer stations, an option which is considered expensive and economically to solve voltage problems although it may be ideal for line overloads.

2. Transformer or line-based techniques where components like on-load tap changers or alternative continuous techniques are applied to change the voltage on a particular line. This consists of hardware components like a transformer with switchable windings and an associated control algorithm. The hardware components are currently available as products today, e.g. in medium voltage level, and at low voltage level. However, the control algorithms are still under research and development. Today, the products like ‘intelligent secondary transformers are equipped with simple controllers based on local measurements (International Energy Agency 2011; Skopik and Smith 2015).

3. Generator-based techniques: In these techniques, the unit causing rise in voltage is also used to keep this rise within limits through reactive power (Q) management or by shedding of active power (P) as last resort. Modern photovoltaic inverters are equipped with selectable P(U), Q(U), Q(P) and cosφ(U) characteristics which are controlled based on local parameters in the inverter. The parameters can also be remote controlled for some products although we are yet to have a widely accepted standardised way to realise this end (International Energy Agency 2015; Skopik and Smith 2015).

7.9. Challenges facing smart grid power systems and technologies

SGs can deal with many current issues with the traditional grid by application of cutting-edge technology with a plethora of chances to improve the efficiency and reliability of power systems. However, several socioeconomic and technical can hinder their deployment and applications (International Renewable Energy Agency 2019). Since the grid is a complex architecture, decentralisation by use of SGs brings tremendous benefits at a cost. However, the digitalisation and integration of a large number of growing users makes SGs soft targets for cyber-attacks and breach of confidentiality among other limitations (Skopik and Smith 2015). SG technologies, although promising, have several challenges as summarised in Table 8.

Table 8. Challenges facing SGs.

	Challenge	Causes and Impact	Solution/Recommendations
1	Cost challenges	The main cost elements in SG development are associated with the power transmission and distribution system, electricity metering, and critical technologies. In economic analysis and financial feasibility	A country’s capacity to pay for the development cost for SG infrastructure is paramount which disadvantages developing countries. `Funding by international institutions can facilitate access to requisite funding for SGs.
2	Cyber Security	SGs deployment across the value chain, increases points of interconnection with different information networks which exposes the system to threats of cyber-attack to important power management systems and infrastructure.	Cyber security can be achieved through standardisation. It is necessary to identify weaknesses of the SGs exploited by attackers through SG Systems Treats Analysis and by integration of Systems Security Threat Models
3	Interoperability	Interoperability facilitates connection of different parties to the devices and systems for proper interaction	The interoperability can be achieved through strict implementation relevant standards
4	Physical Security	There is risk to valuable assets and systems that are widely spread across the country of power system boundaries	Investment in facility security and proper sitting away from danger and keeping of intruders and risks through access control.
5	Privacy and Security Policies	Wide scale interconnectivity and system access including the growth of IoT associated with SG development, privacy, and development rises privacy and confidentiality concerns.	Put in place security policies to establish relationships between the consumers, utilities, generating companies, transmission firms, and third parties, although applying security and privacy policies
6	Connectivity	Refers to communications connectivity and interchange within the SG infrastructure and between users or stakeholders.	It is necessary to develop internet and communications infrastructure across the whole power system coverage area.
7	Confidentiality challenges	Access Control and Identity Management is needed for confidentiality of data transmitted via SGs.	Only authenticated users should be allowed access to the control center for transmission, and distribution grids
8	Defence	The SGs have inherent vulnerabilities against which it must be protected. This can be achieved by building an effective, layered defence system for protection of the smart grid infrastructure.	This defence or protection against the threats or vulnerabilities give the network segmentation and access control to defend against denial-of-service (DoS). Technologies used include firewall, virtual private network (VPN), intrusion prevention system (IPS).

From Table 8, challenges facing SGs include high cost of investment and limited access especially for developing countries having multiple socioeconomic challenges, interoperability of standardisation related issues, cyber and physical security, communication and internet connectivity challenges and high system security requirements.

7.10. Role of SGs in the sustainable energy transition

SGs have an important role to play in the sustainable energy and electricity transition within the framework of the five dimensions of energy sustainability. They are summarised in the table below.

From Table 9, it is noted that SG technology still faces sustainability challenges which should be addressed by countries. The table presents the role of SGs in the sustainable energy transition is presented with current challenges. Overall, it is noted that whereas SGs have huge capability or potential to transform power systems, they have several challenges that need to be overcome in all dimensions of sustainability. They include high cost, risks to the infrastructure, volatility of related technology, and huge policy and institutional requirements for sustainable adoption and transformation.

Table 9. Role of SGs in the energy transition and related challenges.

	Dimension of sustainability	Sustainability impact	Challenges
1	Economic sustainability	Converts consumers to prosumers who make revenue and save on cost through variable pricing.	It is difficult to understand and communicate the value proposition of a SG deployment for all stakeholders in the power system. The risk and reward system can challenge business plans for SG investments. Regulatory environment or lack of regulation may create challenges in terms of costs and related expenditures. It is difficult to develop and implement an appropriate incentive structure aligning economic and regulatory policies with energy-efficiency and environmental goals. SG infrastructure is expensive to deploy and requires highly trained personnel.
2	Environmental sustainability	Reduces greenhouse gas emission through higher absorption of variable renewables. As well as high efficiency hence less consumption	The level of emissions reduction is highly dependent on the energy mix. Not all areas are endowed with abundant supply of solar and wind resources to exploit decentralised power generation.
3	Social sustainability	Maximum use of local energy resources, employment and cleaner environment and participatory operations	Valuation of smart system externalities is difficult making balanced decision making. SG technology deployment and implementation requires highly skilled manpower hence high staff development cost and time. It is difficult to value the value of benefits to the community in terms of jobs and advancement of skills.
4	Technical sustainability	Facilitate MGs and decentralised generation. Increases reliability, efficiency, and optimum use of all energy resources in the system as wee as the infrastructure.	Need for designs to accommodate multiple technologies due to constant technology changes. Flexibility to changing technologies requires identifying the important interfaces between technology components which may be difficult. Limited standardisation as the industry is still evolving.
5	Institutional sustainability	Facilitates active participation of all stakeholders where all stakeholders benefit.	Develop policies that support the deployment of renewable sources and efficiency in electricity transmission, distribution and consumption which create demand for smart energy systems. Countries should set up regulatory regimes that encourage investment and deployment of SG technology and infrastructure. There should be an appropriate incentive structure that aligns sustainable energy with SG technology.

7.11. Recommendations

The successful adoption of SGs to make them sustainable option in the energy transition require measures that include.

1. Put in place policy measures to develop a common framework for the development of SG that may be unique to each country for successful deployment of SGs globally.

2. All stakeholders like consumers, service providers, suppliers, and regulators should play leading roles in shaping the goals and required standards and level of performance.

3. There is a need for education and sensitisation is on use and benefits of the deployment of SGs to governments and stakeholders.

4. Understanding and communicating the value proposition of an SG deployment for each stakeholder in the electricity supply chain is daunting.

5. The financial environment for risk and reward can challenge business plans for SG investments.

6. Need for development of internationally acceptable quality and operational standards to manage the challenge of interoperability.

7. Governments should put in place necessary regulatory measures to govern the development and operation of SGs and facilitate harmonious integration and cooperation between all stakeholders. This is because regulatory decisions (or lack of decision) can create new challenges to the deployment and operation of SGs.

8. There is need for developing an appropriate incentive like attractive fed in tariffs for prosumers and flexibility in pricing that is aligned with requisite economic and regulatory policies where energy-efficiency and environmental protection needs to be the ultimate objective or target.

9. The volatile nature of SG-related technologies implies that there should be provision for a heterogeneous mix of technology so that existing generation and delivery infrastructure (i.e. legacy) systems can be seamlessly adapted to work with new technologies. To be flexible to technological changes needs the identification of important interfaces between various technology components.

10. To realise or achieve alignment across stakeholders like service providers, end-users, and technology suppliers is a challenge which should be addressed by enforcing interoperability can allow multiple parties and devices to interact smoothly and seamlessly. This requires standards and an effective legal and regulatory framework to facilitate a smooth transition and operations.

Wider adoption or development of SGs requires amendment or development of facilitating legislative and regulatory frameworks for countries still using the traditional grid (Mostafa, Ramadan, and Elfarouk 2022). There is a need to develop incentives for increased adoption of renewable energy technology, measures that promote electrification of transport which is an important user of SGs like tax measures, workforce capacity building and wider public awareness campaigns to enlighten the public and grid stakeholders to create a mass movement for development and adoption of SG technologies and related products and services for sustainable transition (Boden, Marland, and Andres 2017; Mostafa, Ramadan, and Elfarouk 2022; Owusu and Asumadu-Sarkodie 2016).

8. Conclusion

The SG is a technology of the future whose primary objective is to reduce costly peak demands, maximise absorption of variable renewables and reduce energy-related greenhouse gas emissions and facilitates dynamic pricing which enhances consumer awareness and participation in power generation and consumption. Advances in SGs will add value to the electrification of transport making millions of cars not just exist as variable loads, but act as renewable energy storage devices and sources of decentralised power for grids. The SGs facilitate increased efficiencies in power consumption usage monitoring, direct power supplies to serve peak power demand, and enhance the efficiency of electricity delivery. SGs apply digital technology to avail electricity in the form of an extensive cyber-physical power system which can enable controllability and responsiveness of decentralised electricity generation and supply within the overall power grid system. The SG is the direction and trend of power industry development based on the physical grid and that combines advanced information and communication technology with the operation technology the traditional grid to form a smart system. The main links covered by the SG are power generation, transmission, system transformation, power distribution, electricity consumption, and dispatch. The SG coordinates the needs and functions of different participants in the grid environment enabling the system to operate on the premise of ensuring system reliability and stability.

The SG applies wireless sensor networks (WSNs) communication technologies which are cheaper, faster to deploy, enhances flexibility, and aggregated intelligence via parallel processing capabilities. The IoT, which is a characteristic feature of SG systems refers to the application of wireless sensor networks (WSNs), smart meters, actuators and components with ICT in operations. The main limitation or challenge with the integration of the IoT technology within the smart power grid is the introduction of costly large data processing. The data handled within the SG system includes end users load demand, faults on power lines, status of network components, scheduling energy consumption, forecast information and conditions, records on advanced metering, outage management records, and records of enterprise assets.

The SG is a product of the 4IR whose overall result is growth in automation, better communication, self-monitoring, and the application of smart machines which have ability to analyse and diagnose issues without with little or no human intervention. The SG revolution also represents a social, political, and economic shift from the digital age of the late 1990s and early 2000s to a connectivity-embedded era which is distinguished by the omni-use and commonness of technological use throughout society. The 4IR technologies have the potential to connect billions of people globally to the web and significantly improve the efficiency of doing business globally and improve the standard of living and efficiency in doing many things globally.

Advances in SG technology present opportunities to efficiently meet future energy needs by reducing carbon emission and increasing the integration of renewable energy resources in the electricity mix. The technology can improve power system reliability, quality, and efficiency of power delivery by introducing and facilitating positive consumer behaviour in energy use. Significant potential exists for improvement and implementation of SG concept which is still under development and adoption and hence the need for government policies and measures to facilitate the implementation of SGs globally. The capacity of the grid to absorb VREs of energy is achieved by grid smartening using intelligent systems. These intelligent systems improve reliability, efficiency, and capacity of the grid to deal with variability and intermittence. The use of MGs as building blocks for SGs increase access of renewable sources of energy into the mainstream power systems besides increasing efficiency and optimal use of grid facilities through DR and peak shaving.

There is growing demand for new approaches in electricity grid operation, control, and maintenance for increased uptake of highly variable renewable energy as well as DERs. Other than variable sources, loads like PEVs and vehicle-to-grid have significant potential for increase if the SG infrastructure is available. Therefore, SGs enable the implementation of strategies to achieve energy and environment sustainability, and climate change control which makes SGs very useful infrastructure to use in realisation of sustainable energy development. The use of Information Communication and Technology (ICT) in the form of digital and internet technology in electricity networks is a working strategy to realise low-carbon power systems by integration of the fluctuating renewable energy sources, improve conversion or generation efficiency by application of real-time coordination of energy flows, and improved power supply security by means of automatic grid reconfiguration and more active consumer participation in energy markets. The digital technology in power generation and supply within an SG system provides an opportunity better economic competitiveness through price competitiveness and high-tech infrastructural modernisation and the attraction and development of high-skilled, well-paying jobs while guaranteeing sustainable energy.

SGs will play a very important role in the ongoing transition from centralised power systems to decentralised systems whose control is influenced by dynamic market forces for investment, operational stability and reliability and facilitate greater absorption of variable electricity like solar and wind as well as variable loads like electric vehicle battery recharging system and related products like V2G and G2V. A sustainable electricity mix and power system will require seamless coordination of both centralised and decentralised power generation and distribution. Therefore, to achieve sustainable development requires electricity systems to adequately respond dynamically, and intelligently to change in demand and supply. This will facilitate energy security, and power quality which are requirements for realisation of technical, economic, and environmental performance sustainability. Therefore, SGs will transform the power sector into a desirable system with reliability, availability, and efficiency, which are requirements for improving the world economy and guarantee environmental protection. However, the transition period requires tests, technological innovations and improvements, consumer education, development of appropriate or requisite standards and regulations, and information sharing or networking between all players in the energy sector to ensure that the benefits of SGs will be realised globally for all humanity.

The SG technology incorporates components of the intelligent energy network system which reciprocate with industry 4.0 namely, Cyber-Physical System, M2M (machine to machine), the IoT whose outcome is the application of technology at all levels in the electricity network. Industry 4.0/4 Industrial Revolution and SG commonalities include elements of optimisation, systems automation, efficient use and management of energy, intelligent decisions, and use of the internet. The overall effect of application industry 4.0 principles in SGs is better system operation, higher energy efficiency, reduced costs, reduced greenhouse effect, reduced downtime, reduced power losses, improved power quality, effective management of generation and storage systems which are key requirements for the energy transition.

The deployment and optimum use of SG infrastructure may require advancement in energy storage technology and facilitating policy, legal and socio-economic environment. The study showed that many components of SG systems can be progressively deployed based on new initiatives, policy initiates, and specific frameworks adopted for implementation by the government or responsible authorities. There exists significant potential of SG technology in the entire energy sector that can deliver effective and efficient utilisation renewable energy resources, protection of the environment, better energy management, and overall socioeconomic development of all countries. The success of SG technology requires that governments and energy sector authorities should put in place policies and frameworks that support and prioritise the investment that promotes the use of renewable energy technologies and integration in the entire national electricity grid and all electricity applications.

Availability of data

The research has provided all data and information used and did not use any undeclared data and information. However, any datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Authors contribution

The first author (Moses Kabeyi) conceptualised and drafted the manuscript which was reviewed and improved by the second author (Alodulapo Olenwaraju), who also facilitated any form of funding related to the research.

Acknowledgements

The authors wish to appreciate reviewers, researchers, and scholars in the field of geothermal energy and electricity for providing significant, credible, and reliable information in all aspects of geothermal energy with ready access. As authors, we thank Michael Vermeer who edited our work and gave it the current shape. The authors thank Joseph Akpan (https://orcid.org/0000-0001-7988-1901) for organizing the manuscript and reviewers for providing suggestions to improve this paper.

Disclosure statement

No potential conflict of interest was reported by the author(s).