Modeling the Operation Mechanism of Combined P2G and Gas-Fired Plant With CO2 Recycling

The rapid development of power-to-gas (P2G) technology is promoting the integration of renewables and the interaction between multiple energy systems. In this paper, the concept of combined P2G and gas-fired power plant (GFPP) system is proposed as a potential solution for the globally recognized imperatives to reduce CO2 emission and utilize renewable energy. The proposed system is featured by the on-site conversion of CO2 back to the fuels of GFPP and thus recycles CO2 without long-distance transport. This paper further establishes the mathematical model of the proposed system. Detailed gas, electricity and heat flow inside the system are explained and the input/output relationship is derived as well. This paper also studies the operational range and optimal scheduling method of the proposed system to quantify its ability on the reduction of CO2 emission and utilization of renewables. According to the estimation, the GFPP-P2G system is able to utilize approximately 30% of the surplus renewables for electricity generation and 20% for heat generation. The combined GFPP-P2G system is also compared with the standalone GFPP through several cases. The numerical study shows great effect of the proposed system on the utilization of renewables and reduction of CO2 emission.