Identifying enablers for accelerated uptake of electric bus in Kolkata city in India

Abstract

Kolkata’s sustainability and liveability are impaired by uncontrolled emissions from vehicles that rely on traditional fossil fuels. Adoption of environment-friendly energy-efficient technologies like Electric Vehicles (EVs) is urgently required in the city. EV is a suitable option for both public and private transport. However, like other new technologies, EVs are also required to be facilitated by different enablers and drivers. Kolkata executed a pilot project of deploying 80 Electric Buses (e-bus) during 2017–2020 and is considering large-scale uptake of e-buses. The purpose of this study is to investigate the various elements that are crucial to accelerated large-scale e-bus adoption in the city. A survey of two hundred stakeholders from ten relevant entities is carried out through the statistical technique of Principal Component Analysis (PCA). The results indicate five key factors for faster e-bus adoption; (i) Successful e-bus pilot project, (ii) Setting up of an EV Accelerator Cell, (iii) Capital and operational Instruments, (iv) Publicity/Awareness Programs, and (v) Awards and Appreciation for the pilot e-bus project deployed in the city.

Keywords:

• Sustainability
• livability
• electric buses
• energy efficiency
• drivers

1. Introduction

Cities consume 75% of global energy and emit 70% of global CO₂ emissions (IPCC, 2022; IRENA, 2021). In most developing country cities, transportation is the highest energy consumer with its consequent impact on the environment (IEA, 2016; Ram et al., 2022; UN-HABITAT, n.d.). A large share of the transportation demand is met by public transport (primarily diesel-powered buses) in many Indian cities.

Electric vehicles (EVs) are a potential technology towards envisioning urban sustainability as they reduce fossil fuel demand, air pollution/CO₂ emissions, and operation and maintenance costs, when compared to internal combustion engine (ICE) vehicles powered by petrol or diesel (Gass et al., 2014; Hagem et al., 2023; Kumar & Alok, 2020; Xiong et al., 2023). To achieve net zero emissions by 2050, EVs score better in terms of environmental and economic implications as compared to ICE vehicles (Veza et al., 2023). In addition, EVs have other advantages including zero tailpipe emissions, increased low-speed acceleration, and decreased interior noise and vibration (Bhatti et al., 2021; Buekers et al., 2014).

Thus, the option of replacing diesel buses with electric ones (e-buses) in Indian metropolitan cities can play a key role in addressing their high energy demand & emission issues from the transport sector. In the last decade, the e-bus technology has matured and has been adopted widely. Shenzhen in China has the world’s first and largest fully electric bus fleet of around 17,000 e-buses (Berlin et al., 2020). Other Chinese cities like Tianjin and Zhengzhou, also have achieved 100% of bus fleet electrification (Yiyang & Fremery, 2022). Large-scale e-buses have been deployed worldwide in cities including Bergen, Hamburg, London, Gothenburg, Milan, Utrecht, and many others. However, despite the technology’s potential to provide a more sustainable and cleaner environment, large-scale uptake of e-buses is still not prevalent in India. Compared to 2.3 million diesel and CNG buses, only around 4000 e-buses are currently operational on Indian roads (BS, 2023).

Amongst the Indian cities, Kolkata, the capital of West Bengal recently reported very high pollution levels in 2019; globally it ranked second in population-weighted annual average PM2.5 exposures (Health Effects Institute, 2022). PM2.5 is mostly emitted by the transport sector. The sector also contributes more than 68% of the Greenhouse Gas (GHG) emissions in the city (WB, 2020). Increasing transportation demand, motorization, and consequent fossil fuel consumption in the city are major contributors to these high pollution levels.

More than 60% of Kolkata’s transport demand is met by public/semi-public modes (bus, metro, taxi, and 3-wheelers) of which buses have the highest share (about 40%) (WB, 2020). Both Government and private buses ply in the city. The government buses are owned and operated by West Bengal Transport Corporation (WBTC). The private buses are mostly owned by individuals and they also carry a large share of bus trips in the city.

WBTC deployed a pilot e-bus project during 2017–2020, by procuring 80 e-buses for the city with the financial support of the Faster Adoption and Manufacturing of Hybrid and Electric Vehicles (FAME) 1 subsidy by the Government of India (GOI) and is considering a large-scale uptake of the e-buses with FAME subsidy. Similar to adopting e-buses in the public bus fleet, introducing them in the private bus segment will further curb the energy demand and subsequent emissions from the transport sector in the city. In June 2021, West Bengal released its EV Policy (WB EV Policy, 2021) focusing on an expedited uptake of EVs in both public and private transport segments. However, immediate actions and enablers are needed for the EV Policy’s rapid implementation and a quicker switch to EVs. Drivers leading to accelerated e-bus adoption in Kolkata need to be identified and addressed urgently. Such focused analysis on the drivers and parameters for faster adoption of electric mobility in the public transport segment in Kolkata has not been carried out earlier.

Researchers have recently investigated a range of determinants and facilitators to facilitate the rapid adoption of electric vehicles; most of these studies have focused on industrialized nations. The studies focusing on India and other developing countries have mostly focused on drivers for promoting EV adoption in the country as a whole; few studies have focused on the drivers in developing countries’ urban contexts (Inci et al., 2022; Palit et al., 2022).

In this context, this study is carried out. It aims to identify and analyze the key drivers for e-bus uptake in Kolkata by WBTC and focuses on two segments: (a) drivers for the uptake of pilot e-bus project (80 e-buses which are already operating in the city) in Kolkata and (b) accelerated large-scale uptake of e-buses in the city. The research also examines the respective importance/contributions of all the identified drivers. An opinion survey (Delphi method) and Principal Component Analysis (PCA) technique are adopted to carry out the task.

It is envisaged that the results of the study will facilitate policymakers to adopt measures resulting in faster deployment of e-buses in Kolkata, thereby resulting in reductions in fossil fuel demand and vehicular pollution in the city. The research includes inputs and validation of experienced policymakers, academicians, manufacturers, and other relevant experts. The study framework can also be extended to other national and international cities with required modifications according to their geographical coordinates, governance structure, constraints, and challenges and it will be helpful for them to strategize measures for accelerated adoption of e-buses.

2. Literature review

This section includes the current e-bus scenario in Kolkata, a comprehensive review of the literature on key drivers of e-bus adoption worldwide, and the research gaps.

2.1. Current e-bus scenario in Kolkata

WBTC adopted a pilot e-bus project in the public transport segment in Kolkata during 2017–2020 where 80 e-buses were procured with FAME subsidy. The Department of Heavy Industries (DHI) of the Government of India provides financial support under their FAME program. This subsidy enabled Kolkata to carry out one of the country’s first significant pilot e-bus initiatives. All these 80 buses are successfully operating in the city. They are charged using charging stations installed in the bus depots.

In recent times, WBTC has been considering large-scale e-bus procurement in OPEX mode with support from the FAME II program. In addition to WBTC-run buses, a large number of privately-owned diesel buses also operate in the city and e-bus uptake by them is negligible. Shifting these private buses to e-buses will lead to savings in fossil fuel and emissions.

2.2. Key drivers for the successful adoption of e-buses worldwide

Literature available on various drivers for global e-bus adoption is reviewed which indicates that faster deployment of e-bus encompasses several enablers; e-bus deployment worldwide has been driven by more than 30 factors. The key factors identified in various studies on the driving forces behind EV adoption include (a) adequate charging infrastructure and favourable government policies, (b) innovations in the electric mobility technology and charging systems, (c) financial and fiscal incentives for EV adoption, and (d) Awareness generation on EVs, environmental consciousness and pride in EV ownership (Aasness & Odeck, 2023; Austmann, 2021; Carley et al., 2013; Choi et al., 2022; Coffman et al., 2017; Ghosh & Bhaduri, 2023; Guno et al., 2021; Hagem et al., 2023; Helveston et al., 2015; Inci et al., 2022; Jenn et al., 2018; Liao et al., 2017; Melander et al., 2022; Sierzchula, 2014; Xiong et al., 2023; Zhang et al., 2016).

To achieve the goal of EV adoption for clean public transport systems, Kumar et al. (2023) compared the adoption of EVs in the Global North and South and recommended that the following critical areas warrant immediate action: the success of pilot projects; the development of technical infrastructure; the availability of financial resources; the improvement of consumer perceptions towards EVs; and the policies and plans by the local and national government. According to Rohilla et al. (2024), wealthier nations have embraced electric vehicles (EVs) significantly more quickly than developing ones, especially when it comes to well-designed charging infrastructure and financial incentives from the government. According to Tarei et al. (2021), performance and range, the overall cost of ownership, a lack of infrastructure for charging, and a lack of customer knowledge about EV technology are the main obstacles to EV adoption in India. According to empirical data, the EV market was strongly correlated with institutional isomorphism brought up by legitimacy (Khatua et al., 2023).

For easier comprehension and representation, many authors while conducting driver/barrier analysis, have classified them (like policy, technology, finance, awareness, cultural, social, etc.) where the number of drivers/barriers are many (Seetharaman et al., 2019). Thereby, in this study, the e-bus drivers identified through the comprehensive literature review are broadly classified into four categories, which include (a) policy and regulatory, (b) technical, (c) financial and economic, and (d) informational/social/cultural (Table 1).

Table 1. Drivers for electric bus adoption.

Type	Divers	Author
Policy/regulatory drivers	Regulations for planning e-bus deployment and facilitating fast-charging infrastructure	Thorne et al., 2021
	Encourage e-buses while considering the implications for electricity generation, land usage, and policy.	Logan et al., 2023
	Policies for bus rapid transit charging infrastructure	Manzolli, 2020
	Regulations on deployment of charging infrastructure	Coffman et al., 2017
	Relevant government policies towards faster EV uptake in private and public transport	Guno et al., 2021
	Policy on regulations, subsidies, and environmental zones wrt EV technology	Melander et al., 2022
	Recharge stations and policy incentives for the use of hybrid and electric vehicles in the public and private sectors	Inci et al., 2022
	Extensive public infrastructure for EV adoption	Kongklaew et al., 2021
	Market regulations, adequate charging infrastructure	Costa et al., 2020
Technological drivers	Establish infrastructure and auxiliary energy supply	Thorne et al., 2021
	Development in improved fast charging technologies for e-buses and e-cars to address the concerns regarding long charging times and limited driving range	Choi et al., 2022; Li et al., 2023; Xiong et al., 2023
	Various advantages like zero tailpipe emissions, low energy consumption, and low noise level led to e-bus adoption thereby reducing carbon emissions and oil dependence	Xu et al., 2019
	Integrating EV infrastructure and telecommunications will create and support new opportunities in both public and private transport	Say et al., 2023
	Innovations in E-bus technology	Melander et al., 2022; Zhang et al., 2016
	Absence of technology and policy for Li-ion battery recycling and disposal (India)	Das & Bhat, 2022
	Increased the density of EV charging stations	Zhang et al., 2016
Financial drivers	Financial incentives for encouraging EVs in the public transport sector	Coffman et al., 2017
	Large role of transport authorities regarding e-bus deployment until cost parity with diesel buses is achieved	Thorne et al., 2021
	Cost-competitiveness and ability of e-buses to combat high impacts of harmful emissions in large cities and metropolises	Avenali et al., 2023
	Economic as well as the health and environmental benefits of e-buses led to their adoption	Pagliaro & Meneguzzo, 2019
	Gross cost contract mechanism offered to e-bus operators in many countries	Hensher, 2021
	Solving financial challenges of procuring e-buses	Guno et al., 2021
	Availability of subsidies for e-buses, Incentives and subsidies for research and production of e-buses	Choi et al., 2022; Helveston et al., 2015; Inci et al., 2022; Melander et al., 2022
	Incentives like waiver of tolls and other municipal incentives, exemption from registration tax and VAT (Oslo)	Aasness & Odeck, 2023; Costa et al., 2020; Zhang et al., 2016
	lack of charging stations, higher purchase prices, lack of long-term planning, absence of repair and maintenance workshops, and the absence of a tax exemption policy (Nepal)	Adhikari et al., 2020
	Promotions of tax breaks along with incentives to producers and consumers	Veza et al., 2023
	Usage of biofuels and development of high-capacity infrastructure with investment and financing of EV research/development	Gonçalves et al., 2022
	Tax incentives and EV awareness	Bryła et al., 2022
	Investments in public charging infrastructure to promote e-buses and all other types of EVs	Hagem et al., 2023
Informational/social/cultural drivers	Reducing uncertainties connected to technology, operations, and infrastructure through education and publicity	Melander et al., 2022
	Energy management strategies by city authorities	Manzolli, 2020
	Acceptance of e-bus technology by citizens	Guno et al., 2021
	Studies on the psychological aspects of using EVs for both private and public transportation	Austmann, 2021
	Consciousness of authorities about the environmental impacts of ICE vehicles thereby promoting EVs in public and private transport	Choi et al., 2022
	Breaking barriers like lack of (a) EV experience and (b) misinformation on adverse effects of EVs on the environment	Almansour, 2022; Inci et al., 2022
	Raising public awareness through education regarding the environmental and economic benefits of greener transportation.	Veza et al., 2023
	Environmental concern and EV product-related determinants, such as ease of use, perceived risks, and relative advantage of all EV modes	Inci et al., 2022; Roemer & Henseler, 2022

Source: Author.

2.3. Research gaps

The global automotive sector is currently undergoing a paradigm transition from ICE vehicles to a technology-ready, economically viable, and cleaner option of electric mobility (EV) resulting in savings in fossil fuel demand and GHG emissions (Haddadian et al., 2015; Liu et al., 2017). Drivers and enablers of adopting EVs have become a key topic for researchers worldwide.

However, studies specifically focusing on drivers for faster EV uptake in the public transport segment (e-buses) are predominantly carried out from the developed country perspective (Kumar & Alok, 2020). Research in the emerging economies mostly focuses on EV enablers adoption in the entire transport sector [public (bus), semi-public (cabs/3 wheelers) and private transport (cars, 2 wheelers) and not particularly on the public transport segment (Dixit & Singh, 2022; Pandita et al., 2022; Tarei et al., 2021). However, the enablers for expedited EV adoption in public transport might be completely different than those for semi-public or private transport segments. Furthermore, a thorough examination of the requirements for implementing electric transportation, particularly in the public transport segment in Kolkata has not been explored.

Considering diesel-driven buses cater to a major share of transportation demand in Kolkata leading to vehicular pollution from fossil fuel, replacing diesel buses with e-buses is needed in the city urgently. It may be noted that despite favourable policies (WB EV Policy, 2021) and financial incentives (FAME program), uptake of e-buses has been slow in the city, indicating the requirement of additional drivers and enablers for pushing the technology faster. Identifying such initiatives is imperative for its enhanced accelerated and successful adoption.

With this background, this study envisages identifying the key drivers and enablers that will facilitate a successful and accelerated e-bus uptake in Kolkata.

3. Research methodology

Identification and analysis of the key factors and their respective contributions in the pilot e-bus project in Kolkata and its large-scale accelerated uptake in the city are determined through the following steps:

• Step 1: formulation of key drivers for both the pilot e-bus project in Kolkata by WBTC and its large-scale accelerated uptake and their validation by experts. The survey questionnaire is developed based on these drives.

• Step 2: opinion survey of 280 stakeholders.

• Step 3: statistical analysis of data gathered from the survey to determine the crucial factors, their contributing drivers, and respective contributions for the uptake of pilot e-bus project in Kolkata and large-scale accelerated uptake of e-buses in the city.

3.1. Step 1: Formulation of drivers of pilot and accelerated e-bus uptake in Kolkata

At the outset, the potential drivers for both the pilot e-bus project in Kolkata and its large-scale accelerated uptake in the city are formulated by the author based on (i) the literature review on the adoption of e-buses, (ii) secondary data, and (iii) consultation with relevant stakeholders including experience of WBTC officials wrt deployment of the pilot project of eighty e-buses in Kolkata. These identified drivers are then validated, refined, and ascertained by 20 experts (policymakers, sector specialists, and other relevant stakeholders with at least 15–20 years of experience in the subject). The drivers are included in Tables 2 and 3.

Table 2. Drivers for pilot e-bus project in Kolkata.

Drivers	Abbreviation
Policy drivers
WBTC Policy to apply for E-bus procurement under FAME II	P
Formulation of “EV accelerator cell” in WBTC	P
Coordination with Private Bus Association towards shifting diesel-run buses to e-buses	P
Technology drivers
Successful pilot e-bus project—satisfactory performance and demonstrated energy (fuel) savings	T
Setting up charging infrastructure in bus depots	T
Financial drivers
Demonstrated cost savings in pilot e-bus project—O&M cost cheaper than diesel buses	F
Minimal financial implications—purchase of e-buses under OPEX model of FAME II (no upfront cost)	F
Financial incentives for private bus operators to adopt e-bus technology	F
Exemptions of road tax/registration fees	F
Social/informational/cultural drivers
Awareness generation in TV, print and social media about benefits including techno-economic feasibility and potential savings demonstrated from the pilot e-bus project	I
Information exchange regarding ease of uptake of e-buses in other cities thereby removing the performance uncertainty and other challenges	I
International awards received by Kolkata for India’s first successful e-bus pilot	I
Training of relevant STKs in STU on e-bus technology	I
Awareness generation about e-bus success in cities worldwide	I
Appreciation by the citizens of Kolkata—greener, comfortable, environment-friendly ride bye-buses	I

Source: Authors, in discussion with experts.

Table 3. Drivers for accelerated uptake of e-bus in Kolkata.

Drivers	Abbreviation
Policy drivers
WBTC Policy to apply for E-bus procurement under FAME II	P
Formulation of “EV accelerator cell” in WBTC	P
Coordination with Private Bus Association towards shifting diesel-run buses to e-buses	P
Technology drivers
Successful pilot e-bus project—satisfactory performance and demonstrated energy (fuel) savings	T
Setting up charging infrastructure in bus depots	T
Financial drivers
Demonstrated cost savings in pilot e-bus project—O&M cost cheaper than diesel buses	F
Minimal financial implications—purchase of e-buses under OPEX model of FAME II (no upfront cost)	F
Financial incentives for private bus operators to adopt e-bus technology	F
Exemptions of road tax/registration fees	F
Social/informational/cultural drivers
Awareness generation in TV, print and social media about benefits including techno-economic feasibility and potential savings demonstrated from the pilot e-bus project	I
Information exchange regarding ease of uptake of e-buses in other cities thereby removing the performance uncertainty and other challenges	I
International awards received by Kolkata for India’s first successful e-bus pilot	I
Training of relevant STKs in STU on e-bus technology	I
Awareness generation about e-bus success in cities worldwide	I
Appreciation by the citizens of Kolkata—greener, comfortable, environment-friendly ride bye-buses	I

Source: Authors, in discussion with experts.

Based on these drivers, Questionnaires for the opinion survey are developed.

3.2. Step 2: Opinion survey

This study is based on inputs from 280 pertinent stakeholders representing government, private, academician, legal/media, and NGOs. Before finalizing the most suitable survey method for this study, a review of the different options is undertaken. The various types include the Delphi Method (Questionnaire Survey), Interview (through long discussions, not formal questionnaires), Meta-analysis (Big data reqd, not suitable in this study), Observation-based (validation required), Optimization techniques (linear programming, the objective of the study is not optimization, but identifying the key enablers), secondary data analysis (literature review basis), Simulation-based (not applicable for this type of analysis). A Survey-based method is robust and most popular for these types of studies (Helveston et al., 2015; Kumar & Alok, 2020). Thereby, after a detailed review, the Delphi method is adopted for the Opinion Survey in this analysis. The advantages of the Delphi method include (a) enables aggregated opinions from a diverse set of experts/stakeholders, (b) bringing everyone together for a physical meeting is not required, (c) respondents have the option of being anonymous without having to worry about repercussions, and (d) effective method for reaching consensus.

Delphi is a process of arriving at a group opinion or decision by surveying a panel of experts (minimum of 30 respondents). It is a series of questions leading to developing ideas around an issue. The strength of the agreements is measured through a rating scale. Most commonly, Likert scales between 4- and 7-points are used for answering the questions (Involve, 2023; Typeform, 2023). In this study, a 5-point Likert scale is adopted; respondents are requested to rank the relevance of the survey questions with severity between 1 and 5. Two hundred and eighty pertinent stakeholders from business and governmental institutions in Kolkata and other cities working in the transportation, energy, and environment sectors and common citizens are identified for the survey. Table 4 displays the profile of the survey participants.

Table 4. Share of respondents.

S.N.	Profession	Share (%)
1	Academician & Think Tanks	10
2	Federal/Central Government	9
3	Consumers	16
4	Energy Consultant	12
5	FI/Bilateral Agency/Donor	5
6	Legal/media/NGO	5
7	Private Sector	7
8	E-bus Manufacturers	12
9	State Government	19
10	Urban Local Body	5
	Total	100

Source: Author.

The questionnaire was sent to the 280-survey audience and were asked to rank the relevance of each of the drivers on the 5-point Likert scale. Two hundred and thirty-two of them responded. After cleaning the outliers and incomplete responses two hundred responses were found to be thorough and suitable for the analysis (Table 5).

Table 5. Survey respondents of Delphi survey.

Segment	No of questionnaires
	Sent to	Responses received	Suitable for analysis
Drivers for Uptake of pilot e-bus project Accelerated large-scale uptake of e-buses	280	232	200

Source: Author.

3.3. Step 3: Statistical analysis of Delphi survey data

A review of the available literature on different methods adopted by authors for analyzing the drivers of EV adoption includes Principal Component Analysis (PCA), 2-tuple linguistic method, decision-making trial and evaluation laboratory (DEMATEL) for prioritizing the critical factors, DEMATEL-ISM method, innovation diffusion theory, SWOT analysis, Analytical Hierarchy Process (AHP) and others (Palit et al., 2022). Amongst these, the analytical tool of PCA is particularly useful when variables are multi-collinear in a big data set as PCA transforms several possibly correlated variables in a large data set into fewer variables known as primary (principal) components or factors (Adewumi, 2019; Palit et al., 2022). Hence, PCA has been chosen for this study.

The Statistical Package for Social Sciences (SPSS, Version 20) is used for analyzing the reliability of the Opinion Survey data and carrying out the PCA. Developed by IBM, SPSS is a statistical software that is extensively used for advanced analytics.

After receiving the responses from the Delphi Survey regarding the various drivers of both pilot e-bus projects and their accelerated uptake, the data is first subjected to the Reliability Test, and following their reliability confirmation, they are subjected to PCA for determining the key factors and their respective contributions in pilot e-bus project in Kolkata and its large-scale accelerated uptake in the city.

To confirm the survey data reliability, Cronbach’s Alpha, a measure of survey data consistency is calculated. According to Cronbach (1951), it should have a value between 0 and 1, a higher value indicating greater internal consistency. Following its confirmation, the data is then subjected to KMO for verifying the authenticity check of survey data and then the Bartlett Test. For KMO, a recommended value of 0.500 is advised by Osei-Kyei and Chan (2017). The variables have a highly significant association, as indicated by the Bartlett test of sphericity at <0.0, and qualify the data for PCA (Arokodare, 2021).

After the aforementioned assessments, PCA was performed on data on both segments using the "Dimension Reduction" function in SPSS. The Kaiser Normalization method is used in conjunction with Varimax rotation. The Cattel scree test is conducted to examine the number of components with eigenvalues >1 (graphically represented by scree plots) and their share of accounting of total variance. In this study, these indicate the number of key factors. The Rotated Component Matrix incorporates highly correlated variables under each factor and indicates contributing variables within each of them. This is followed by the Regression Analysis and the key elements/factors and the contributing drivers are then arranged in order of significance (according to the beta coefficient value derived from regression analysis). Thus, the factors, contributing drivers, and their level of contribution are determined for both the pilot e-bus project and its accelerated uptake in Kolkata. Figure 1 presents the statistical analysis framework of the Delphi Survey Data and Figure 2 presents the research methodology.

Figure 1. Statistical analysis framework of the Delphi survey data.

Figure 2. Research methodology.

4. Results

Results of the statistical analysis of both segments (pilot e-bus project and large-scale accelerated uptake of e-buses in Kolkata by WBTC) are included below.

4.1. Reliability test

Cronbach’s alpha values for both segments are >0.7 (Table 6), showing good response, consistency, data reliability, and the suitability of the five-point Likert scale approach used in the analysis.

Table 6. Cronbach’s alpha and KMO values generated in the study.

Statistical test	E-bus pilot project	Accelerated uptake of e-bus
Cronbach’s alpha	0.733	0.769
KMO	0.701	0.702

Source: Author.

4.2. KMO and Bartlett’s test

The KMO value for both segments exceeds the minimum recommended value of 0.500 (Table 6). Furthermore, both segments’ results are statistically significant for Bartlett’s test of sphericity at 0.000, indicating that the correlation is factorable. Hence, the Delphi survey data is deemed appropriate for running PCA to identify the key factors of e-bus deployment in Kolkata.

4.3. PCA

Using the Delphi survey data, the PCA and Cattel Scree tests were performed for both segments using the Varimax rotation with the Kaiser Normalization procedure. The number of factors with an eigenvalue more than one, i.e. the number of factors influencing pilot e-bus project is 4 and that for accelerated uptake of e-buses is 5.

PCA results for the pilot e-bus project including (a) Variance, (b) Rotated Component Matrix, and (c) beta coefficient values (importance levels of factors) are presented in Tables 7–9. The Scree Plot is presented in Figure 4. PCA results for the accelerated e-bus uptake including (a) Variance, (b) Rotated Component Matrix, and (c) beta coefficient values (importance levels of factors) are presented in Tables 10–12. The Scree Plot is presented in Figure 4.

Table 7. Variance explanation—analysis of drivers of for pilot e-bus project.

Component	Initial Eigenvalues			Extraction sums of squared loadings			Rotation sums of squared loadings
	Total	% Of variance	Cumulative %	Total	% Of variance	Cumulative %	Total	% Of variance	Cumulative %
1	3.137	31.371	31.371	3.137	31.371	31.371	1.836	18.360	18.360
2	1.305	13.052	44.423	1.305	13.052	44.423	1.804	18.044	36.404
3	1.094	10.942	55.364	1.094	10.942	55.364	1.644	16.442	52.846
4	1.021	10.215	65.579	1.021	10.215	65.579	1.273	12.733	65.579

Source: PCA, SPSS.

Table 8. Rotated component matrix—pilot e-bus project.

	Components
	1	2	3	4
VAR00010	.804
VAR00002	.731
VAR00008	.604
VAR00009		.860
VAR00004		.711
VAR00001		.563
VAR00006			.802
VAR00007			.740
VAR00003				.786
VAR00005				.627

Source: PCA, SPSS.

Table 9. Coefficients—pilot e-bus project.

Model		Standardized coefficients	Sig.
		Beta
1	(Constant)		<.000
	REGR factor score 1	.498	<.000
	REGR factor score 2	.419	<.000
	REGR factor score 3	.376	<.000
	REGR factor score 4	.268	<.000

Source: PCA, SPSS.

Table 10. Variance explanation—analysis of drivers of accelerated uptake of e-buses.

Component	Initial Eigenvalues			Extraction sums of squared loadings			Rotation sums of squared loadings
	Total	% Of variance	Cumulative %	Total	% Of variance	Cumulative %	Total	% Of variance	Cumulative %
1	3.75	26.85	26.85	3.75	26.85	26.85	2.38	17.00	17.00
2	1.83	13.09	39.94	1.83	13.09	39.94	1.97	14.08	31.08
3	1.24	8.92	48.86	1.24	8.92	48.86	1.74	12.46	43.54
4	1.17	8.41	57.28	1.17	8.41	57.28	1.56	11.16	54.71
5	1.04	7.46	64.74	1.04	7.46	64.74	1.40	10.03	64.74

Source: PCA.

Table 11. Rotated component matrix—accelerated uptake of e-buses.

	Component
	1	2	3	4	5
VAR00003	.865
VAR00004	.731
VAR00006	.651
VAR00001		.759
VAR00005		.713
VAR00014		.570
VAR00002		.508
VAR00007			.744
VAR00010			.714
VAR00008			.671
VAR00009				.745
VAR00013				.600
VAR00012					.719
VAR00011					.662

Source: PCA, SPSS.

Table 12. Coefficients—accelerated uptake of e-buses.

Model		Standardized coefficients	Sig.
		Beta
1	(Constant)		<.000
	REGR factor score 1	.457	<.000
	REGR factor score 2	.449	<.000
	REGR factor score 3	.404	<.000
	REGR factor score 4	.330	<.000
	REGR factor score 5	.105	<.000

Source: PCA, SPSS.

Key Factors & their contributing drivers and for both pilot e-bus project uptake and the accelerated e-bus uptake are given in Table 13 in Section 4.4.

Table 13. Factors, contribution and contributing drivers of e-bus uptake.

Existing status (C Alpha—0.733, KMO—0.701)				Accelerated uptake (C Alpha—0.769, KMO—0.702)
Factors	Drivers	Type	Contribution	Factors	Drivers	Type	Contribution
Local champion and STK coordination	An initiative by local champion	I	0.492	Successful pilot	Ease of uptake	I	0.457
	Feasibility study (E-bus potential in Kolkata)	T			Demonstrated energy (fuel) savings	T
	STK coordination by WBTC	P			Demonstrated O&M cost savings	F
Financial support from Govt	FAME grant (50%)	F	0.432	EV accelerator cell	Apply in FAME II	P	0.449
	WB Fin Dept agreeing to balance 50%	F			Charging infra-bus depots	T
Potential savings	Fuel saving/lower O&M expenses	F	0.410		STK Trg on E-bus tech	I
	Lower investment (GOI policy)	F			Co-ord with Pvt Bus Association	P
	Lower TOD tariff for night charging (HT)	F		Capital and operational instruments	OPEX model FAME II	F	0.404
EV OEMs and after-sales service	Variants, multiple OEMs	T	0.249		Incentives for Pvt Bus Purchase	F
	Maintenance/service, repair by OEM	T			Road Tax/Regn Fee Exemptions	F
				Publicity/awareness	Tech-eco feasibility/Savings	I	0.330
					Experience—World and Indian cities	I
				Awards and appreciation	International awards	I	0.105
					Greener service, comfortable ride	I

Source: PCA, SPSS.

4.3.1. Results—scree plots, variance, rotated component matrix, and beta co-efficient values—pilot e-bus project

Figure 3 depicts the scree plot generated using PCA for the pilot e-bus project, which shows that four components that account for 65% of the total variance have eigenvalues >1. The weighting of these four components ranges from 12 to 18% (Table 7).

Figure 3. Scree plot—analysis of drivers for pilot e-bus project.

Source: PCA, SPSS.

The contributing drivers of the respective factors are presented in Table 8.

Table 9 represents the contribution or importance of each of the factors.

4.3.2. Results—scree plots, rotated component matrix, and beta co-efficient values—accelerated uptake of e-buses

The scree plot derived by PCA for an accelerated e-bus project in Kolkata is presented in Figure 4. It shows that five Components that account for 65% of the total variance have eigenvalues >1. The weighting of these four components ranges from 10 to 17% (Table 10).

Figure 4. Scree plot—analysis of drivers for accelerated uptake of e-buses.

Source: PCA, SPSS.

The contributing drivers of the respective factors are presented in Table 11.

Table 12 represents the contribution or importance of each of the factors.

4.4. Results on the principal components/factors extracted from PCA

The analysis indicates that the drivers for both the segments (pilot e-bus project and accelerated e-bus uptake) that were finalized in discussion with sector experts are distributed among various factors. Those factors having eigenvalues more than 1 are considered as having significant importance and contribution to e-bus uptake. These factors in both segments include a mix of policy/regulatory, technological, financial/economic, and social/informational/cultural drivers. Each of the factors focuses on a distinct theme.

A summary of the factors, their contributing drivers, and beta co-efficient value (contribution in the uptake) for both existing status and accelerated uptake of e-bus technology in Kolkata is presented in Table 8. They are presented in terms of descending order of importance (also drivers within each factor are indicated in their descending order of importance).

The major factors, drivers, and points drawn from the above analysis of the pilot e-bus project indicate the following:

• Factor 1—Local Champion and& STK Coordination: with the highest beta coefficient value (0.492), this is the most important factor in the pilot e-bus project of the uptake of 80 bus deployments in Kolkata in 2017. The initiative, perseverance and push by the Local Champion, preparation of the Feasibility Study on E-bus potential in the city, and necessary stakeholder Coordination by WBTC are the contributing drivers for the pilot project.

• Factor 2—Financial Support from Government: the second key factor leading to the pilot e-bus project in Kolkata is the financial support from the FAME Grant (50% of project cost) and the West Bengal Government Dept agreeing to pay the balance 50%.

• Factor 3—Potential Savings: awareness of potential fuel savings, lower O&M Expenses, Lower Investment (due to FAME subsidy), and the lower TOD tariff for night charging are identified as the key factors (beta coefficient value of 0.410) in the uptake of pilot e-bus project.

• Factor 4—EV OEMs and after-sales service: with the contribution of 0.249, this is the fourth most important factor for the pilot e-bus project. The contributing drivers include the availability of different variants/models of e-bus from multiple manufacturers (OEMs), offering maintenance/service, and repair facilities. Considering e-bus technology was at a nascent stage in 2017, these facilities by OEMs played a major role in its uptake.

The major factors derived from the analysis for the accelerated uptake of e-bus technology in Kolkata are as under:

• Factor 1—Successful pilot (highest beta coefficient value of 0.457): The satisfactory performance of the pilot e-bus project, ease of uptake of the technology, the demonstrated energy (fuel) savings, and cost savings (O&M cost cheaper than diesel buses) came out as the most important drivers for accelerated uptake of e-buses in Kolkata

• Factor 2—EV Accelerator Cell: The quick carrying out of the WB EV policy and the creation of a “Govt EV Accelerator Cell” are the second-most significant factors contributing to Kolkata’s faster adoption of e-buses. The beta coefficient value of these factors is 0.449. The key responsibilities of the EV accelerator Cell towards promoting e-buses in the city include setting up charging infrastructure in bus depots, training relevant stakeholders in WBTC on e-bus technology, and coordinating with the Private e-bus operators towards shifting diesel-run buses to e-buses.

• Factor 3—Capital and Operational Instruments (beta co-efficient value of 0.404): various drivers like minimal financial implications and no upfront investment due to the purchase of e-buses under OPEX model of FAME II, adequate financial incentives and financing options for the private bus operators for adopting e-bus technology, Road Tax/Registration Fee Exemptions will help faster e-bus adoption.

• Factor 4—Intensive Publicity/Awareness Programs (beta co-efficient value of 0.330): Awareness Generation in TV, print, and social media about the benefits of e-buses, their techno-economic feasibility, and savings from the pilot e-bus project, awareness about e-bus success in cities worldwide are extremely important for increased knowledge and removal of uncertainties about e-buses.

• Factor 5—Awards and Appreciation (beta co-efficient value of 0.105): International Awards received by Kolkata for India’s first successful e-bus pilot and appreciation by the citizens of Kolkata regarding greener, comfortable, environment-friendly rides by e-buses are also identified as important drivers for accelerated uptake of e-buses in the city

This analysis indicates the key factors, their contributing drivers, and the level of importance for both pilot e-bus projects and accelerated uptake of e-buses. For an accelerated and successful large-scale adoption of e-buses, all relevant stakeholders need to collaborate and focus on the identified factors and their contributing drivers. This will lead to a sustainable, less polluting, and livable Kolkata. Along with planning for the expedited e-bus adoption, planning for their charging, especially, for the privately owned buses, will have to be worked out simultaneously.

5. Policy recommendations

The key factors for deploying the pilot e-bus project and their accelerated uptake in Kolkata as identified above by PCA in this study are included in Table 14.

Table 14. Factors for e-bus uptake in Kolkata by WBTC.

Pilot e-bus project	Accelerated uptake of e-buses
(i) Local champion and stakeholder coordination	(i) Successful e-bus pilot project
(ii) Financial support from government	(ii) Setting up of an EV accelerator cell
(iii) Potential savings	(iii) Capital and operational instruments
(iv) Multiple original equipment manufacturers (OEMs) of electric buses and after-sales service	(iv) Publicity/awareness programs
	(v) Awards and appreciation for the pilot e-bus project deployed in the city

Considering the pilot e-bus project is already implemented in Kolkata, recommendations in this study focus on their accelerated large-scale uptake. Few policy instruments facilitating the deployment of e-buses are already in place and a few more are proposed for their accelerated uptake in the city.

Owing to the high investment cost of e-buses and charging stations, organizing the capital cost is key to its large-scale uptake. The existing fiscal instruments available for e-buses are crucial for enhancing their uptake. In fact, as indicated in Table 14, financial support (FAME subsidy) and fiscal instruments from the government are identified as key factors for promoting both pilot e-bus projects and their accelerated uptake. However, the subsidy may not continue forever. Creating new business models and financial products for e-buses through collaboration by financers, non-banking finance companies (NBFCs) and other banking institutions is important, especially, for the private e-bus operators/owners, to address the hurdles of high initial capital cost. For the near future, instruments of FAME subsidy, lower electricity tariff for charging, etc. to be continued/extended and additional instruments for e-buses like reduced vehicle registration costs, lower interest rates in vehicle loans, and toll & parking waivers be introduced.

The EV Policy of West Bengal announced in 2021 has not yet been implemented fully. The key mandates of the Policy like the installation of an EV accelerator cell and equipment for charging infrastructure and capacity building of all relevant stakeholders, need to be implemented urgently. The EV Accelerator Cell has a key role to play in accelerated EV deployment in the state in both public and private transport segments and may be housed at the Transport or Power Department.

Citywide charging options, particularly on the e-bus routes, are a prerequisite before expecting private e-bus operators to convert their diesel-run private buses to e-buses. In India, charging stations are set up by power utilities, EV manufacturers, independent charging station operators, vehicle manufacturers/fleet operators, location owners/real estate, and public authorities. As per the amendment in the Electricity Act 2003 by the Ministry of Power, electric vehicle charging is designated as a “service” and no licensing is needed for operating a charging station. Hence, setting up a charging infrastructure network for facilitating the private bus operators across Kolkata should not be a challenge and to be considered a top priority.

Policy/programs on Intense Publicity/Awareness Programs and training of e-bus operators/drivers/other stakeholders (particularly the private diesel bus operators) on all aspects of e-buses are the need of the hour. A platform for convening private bus operators may be formulated and capacity building on topics including e-bus financing options, e-bus products & manufacturers, and after-sales services to be carried out for them. Results on savings in fuel cost and O&M costs from the WBTC pilot project (80 e-buses) need to be disseminated to them urgently. The private diesel bus operators will also need skill development & training in operating & maintaining e-buses.

Moreover, the e-buses will contribute to GHG reduction only if the electricity for their charging is generated from renewable sources of energy. Amongst the different RE options, solar is the most feasible option in Kolkata. To start with, the options of installing solar power in the bus depots can be considered.

With this background, the following recommendations are suggested for accelerating large-scale e-bus uptake in the city:

• Continue existing capital and operational instruments and also explore new financial mechanisms to address procurement cost of e-buses/charging stations

• EV Accelerator Cell proposed in WB EV Policy, 2021 be formulated at the earliest and they need to urgently focus on the following:

  1. Policy roadmap and action plan for setting up citywide charging infrastructure

  2. Bring Private Bus Operators on a common platform and coordinate with them regarding shifting diesel-run buses to e-buses

  3. Collaborate with e-bus manufacturers and undertake Intensive Publicity/Awareness Programs/Training/skill development for relevant stakeholders in the e-bus ecosystem

• Examine options for e-bus recharging with solar power. Rooftops of bus depots and tram depots may be used for solar power generation,

6. Conclusions

About 25% of the energy-related CO₂ emissions in the world are emitted by the transportation sector (Choi et al., 2022). Faster adoption of e-bus technology with zero tailpipe emissions has the potential to achieve improved air quality, and climate benefits, putting cities on track towards sustainability and contributing to achieving net zero. However, despite the promises, the adoption of e-buses has not accelerated fast enough in Indian cities. Kolkata is no exception—although WBTC adopted a pilot e-bus project during 2017–2019 in the city and working on its large-scale uptake, 100% of the large number of private buses are still running on diesel. The predominant barriers and challenges include:

• The high initial capital cost of e-buses: The pilot project of 80 e-buses and its subsequent large-scale e-bus project by WBTC are government-owned buses. Their procurement cost is met by state funds and both these initiatives are also recipients of the Centre’s FAME subsidy. However, the city also has many privately-owned diesel bus operators carrying a large share of bus trips. For them, the high upfront cost of replacing their diesel buses with e-buses is a big challenge. Since these private buses are mostly owned by individuals, the high capital cost of e-buses and the incumbent compliance of the OPEX model of FAME 2 remain a major deterrent for replacing their diesel buses with e-buses.

• Lack of Public Charging Infrastructure: In the case of the government-run e-buses, WBTC has set up the charging infrastructure—they procured and installed the required charging stations in their bus depots across the city for use by their e-bus fleets throughout the day. However, this infrastructure will not be available for the privately owned e-buses. Considering charging stations of e-buses are very cost-intensive (unlike smaller-sized EVs like cars and 2/3 wheelers), their procurement and maintenance are not financially feasible options for the individual owners of the private buses. Also, the buses ply for long ranges and need to be recharged during the day which will not be possible without the availability of a charging network sprawling across the city.

• Poor awareness and know-how on benefits of e-buses, e-bus driving, and the maintenance ecosystem: Compared to conventional diesel buses, e-bus is a new technology and the private bus operators lack knowledge of plying and maintaining them. Also, they are not aware of the information on the savings in diesel and O&M costs from the WBTC pilot project (80 e-buses).

• Also, while executing the pilot e-bus project, the relevant WBTC officials and their e-bus drivers received training from the e-bus manufacturer on all aspects of the technology. Similar training for the privately-run e-bus stakeholders and also, focussed awareness generation activities to alert and educate them on various aspects of e-bus technology are lacking. A platform for convening private bus operators to negotiate on e-buses is missing.

• Current use of non-renewable energy for battery charging: Attainment of emission reduction from bus transport is difficult with the transition to EV alone. The e-buses will lead to substantial GHG reduction only if they use RE-powered charging, e.g. Hydropower, Solar Power, Wind Power, and others. Currently, the RE share in West Bengal’s electricity generation is only 2%.

This study focuses on the drivers/enablers of e-bus uptake in Kolkata for two scenarios: (a) the pilot project of 80 e-buses and (b) their large-scale uptake by WBTC. More than 200 relevant stakeholders including WBTC officials, Policy Makers, e-bus manufacturers, and others were interviewed and Principal Component Analysis (PCA) of the survey data was carried out to identify the key factors for the uptake of e-buses. PCA extracted the drivers into factors having distinct themes. Each theme includes a combination of policy/regulatory, technological, financial/economic, and social/informational/cultural factors. Such an analysis for the public transport segment in Kolkata is carried out for the first time. Policy recommendations are suggested based on the key barriers/challenges of e-bus uptake and the drivers/enablers of large-scale e-bus deployment as determined in this study.

6.1. Key takeaways

This study is carried out in a particular backdrop where first, a pilot project of procuring and operating 80 e-buses in the city of Kolkata has already been undertaken during 2017-19 by WBTC, the state transport undertaking in West Bengal, which, is now planning a large-scale deployment of the e-buses in the city. Considering the research is based on an implemented on-ground project and not a hypothetical one, with inputs from key stakeholders, both national and international cities can draw lessons from the study.

A city-level designated nodal body on EV can suitably facilitate the uptake of the new e-bus technology. For cities planning to deploy e-buses for the first time, a pilot of 60-100 such e-buses is undertaken first and their performances (electricity consumption/charge, range/charge, O&M costs, and battery performance) are monitored for a certain period and disseminated to relevant stakeholders. Upon satisfactory performance of the pilot, their large-scale uptake may be considered. Financial mechanisms and fiscal support from the Government (subsidy towards investment cost, lower electricity tariff, waiver of registration charges, loan at lower interest, and others) will boost their uptake, especially if the buses are owned by private operators. Citywide charging networks (bus depots and along/near bus routes) are mandatory before procurement and operation of e-buses. Skill development/training of relevant stakeholders on the technology and Intensive Publicity/Awareness Programs (about O&M savings and other benefits, e-bus purchase protocols and available financial instruments, their worldwide success, and other topics) are extremely important for increased knowledge and removal of uncertainties about e-buses. Awards & appreciation of cities adopting large-scale e-bus deployment will also encourage their faster uptake in other cities.

An assessment of the global efforts to reach net-zero carbon emissions by 2050 indicates that the various measures in electricity, industry, buildings, transport, and others are failing in almost every way, except the fast induction of EVs (Bezos Earth Fund et al., Climate Action Tracker, United Nations). In India, the promotion of EVs is one of the actions undertaken by GOI to achieve Net-Zero emission targets in the transport sector. Thereby, this study is envisaged to facilitate other national and international cities towards accelerated uptake of e-buses, thereby striving for energy & emission savings and contributing to their efforts to net zero.

7. Limitations of the study and scope of further research

In Kolkata and other Indian cities, it is vital to reduce transportation-related fossil fuel usage and the resulting emissions by switching to energy-efficient choices like e-buses. This study facilitates and enables policymakers to make an informed decision regarding deploying e-buses at an enhanced rate in Kolkata.

Nonetheless, despite its innovativeness and meaningful contributions, there are limitations. It only addresses the deployment of EVs in the public transport sector. Examining the factors that encourage and facilitate increased use of EV technology in the private transportation sector (cars, two-wheelers, and three-wheelers) is vital given the rising energy consumption and ensuing emissions from the transportation sector. In addition, the feasibility of other energy-efficient environment-friendly bus technologies like Fuel Cells and green Hydrogen may be taken up for further research.

Disclosure statement

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