Research on low-carbon economic expansion planning of electric-gas interconnected integrated energy system containing power to gas

ABSTRACT

Under the goal of carbon peaking and carbon neutralization, the integrated energy system will accelerate the cleaner and low-carbon structure transition. In addition, high carbon dioxide emissions in some industrial parks give rise to a series of environmental problems. The emergence of power-to-gas technology provides new insight into solving the problem. This empirical research is an attempt for lower carbon emissions and greater application of renewable energy, and a proposal for an expansion planning model for integrated energy systems considering different sources of CO₂. With the introduction of economic conversion coefficients, carbon dioxide emission is converted into economic dimensions and the other cost together to form the objective function with the minimum cost. The constraints of energy balance, energy network, and equipment output are considered. Finally, through the simulation of the calculation example, the total cost of the carbon capture scenario is reduced by 9.9%, and the carbon emission 24.6% compared with the existing park, which verifies that the proposed model considering capturing carbon dioxide can effectively take into account the low carbon and economic efficiency, and meanwhile enhance the renewable energy accommodation.

KEYWORDS:

• Carbon source
• expansion planning
• integrated energy system
• power-to-gas
• renewable energy accommodation

Parameters

$E_{i,P2G,t,gas}$: the output natural gas volume of P2G equipment $i$ at time $\mathrm{t}$, $m^3$;

$P_{i,P2G,t}$: the electric energy consumed by P2G equipment $i$ at time $\mathrm{t}$, $kW\cdot h$;

$F$: the total cost of the system, thousand yuan;

$f_e$: the electricity purchase cost from the grid, yuan;

$f_g$: the gas purchase cost from the natural gas network, yuan;

$f_{OM}$: the operation and maintenance cost of the system, yuan;

$f_{\mathrm{i}\mathrm{n}\mathrm{v}}$: the annual value cost of the initial investment of the system equipment, yuan;

$f_{C{O}_2}$: the sum of the purchase cost, capture cost, and emission cost of carbon dioxide, yuan;

$f_{m-C{O}_2}$: the purchase cost of carbon dioxide in the integrated energy system, yuan;

$f_{b-C{O}_2}$: the cost of carbon dioxide capture in the integrated energy system, yuan;

$f_{c-C{O}_2}$: the cost of carbon emissions, yuan;

$\mu \left(t\right)$: the purchase price of carbon dioxide during the period $t$,$yuan/t$;

$M\left(t\right)$: the purchase amount of carbon dioxide during the period $t$,$t$;

$\beta \left(t\right)$: the capture price of carbon dioxide during the period $t$,$yuan/t$;

$C\left(t\right)$: the capture amount of carbon dioxide during the period $t$,$t$;

$F_{tot}^d\left(t\right)$: the amount of gas purchased on the gas network at time $t$ on day $d$, $m^3$;

${\alpha }_{gas}$: the carbon dioxide emission coefficient of natural gas, $t/m^3$;

$E_{grid}^d\left(t\right)$: the power purchased by the grid at time $t$ on day d, $kW\cdot h$;

${\alpha }_e$: the CO₂ emission coefficient of power grid purchase, $t/kW\cdot h$;

${\lambda }_{C{O}_2}\left(\mathrm{t}\right)$: the carbon dioxide emission cost coefficient, $yuan/t$;

$E_c$: the carbon emission reduction by CO₂ capture in the P2G process, $t$;

$f_{P2G}$: the amount of synthetic natural gas produced by the P2G equipment at time $t$, $m^3$;

$P_{e-grid}(t)$: the output power of the power grid at time $t$, $kW$;

$P_{e-WT}(t)$ and $P_{e-PV}(t)$ are the output power of the WT and PV at time $t$, $kW$; $P_{e-CHP}(t)$: the output power of CHP at time $t$, $kW$;

$P_{e-load}(t)$, $P_{e-P2G}(t)$and$P_{e-EB}(t)$: the power consumption of users, P2G equipment, and electric boilers at time $t$, $kW$;

$P_{h-CHP}(t)$,$P_{h-EB}(t)$: the thermal output power of the CHP and EB at time $t$, $kW$;

$P_{h-load}(t)$: the thermal load power of users at time $t$, $kW$;

$Q_{s,t}$: the air flow rate supplied at air source point $s$ at time $t$,$m^3$;

$p_{a,t}$ is the pressure of node $a$ at time $t$,$Pa$;

$R_c$: the limit of the compression ratio of compressor $c$;

$F_{p,ab}$: the limit of pipeline transportation flow, $m^3$;

$P_{i,t}$: the active output of the generator set at time $t$,$kW$;

$Q_{i,t}$: the reactive output of the generator set at time $t$,$kW$;

$U_{m,t}$: the voltage of node $m$ at time $t$,$V$;

$P_l$: the line power flowing through the transmission line $l$,$kW$;

$S_{P2G}$: the capacity of the P2G equipment, $kW$;

$P_{P2G,\mathrm{t}}$: the operating power of the P2G equipment at time $t$,$kW$;

$u_{P2G}$: the upward climbing limits of the P2G equipment, $kW$;

$d_{P2G}$: the downward climbing limits of the P2G equipment, $m^3$;

$S_{s,i,t}$ is the storage capacity of gas tank $i$ at time $t$,$m^3$;

$Q_{s,i,t}^{\mathrm{i}\mathrm{n}}$ is the injection flow rate of gas in the gas storage tank $i$,$m^3$;

$P_{equipment,i}^{\hspace{0.17em}}$: the operating power of the existing equipment $i$,$kW$.

Acknowledgments

This paper is supported by “Key R & D Program Project of Hebei Province (19216109D)” and “Major supporting projects in Hebei (SGHEJY00NYJS2000055)”.

Additional information

Funding

This work was supported by the Major supporting projects in Hebei [SGHEJY00NYJS2000055]; Key R & D Program Project of Hebei Province [19216109D].