A comprehensive decarbonized generation expansion planning framework considering coal-to-gas conversion, retirement, and carbon capture retrofit

The decarbonization transition of the energy sector to align with the Paris Agreement's goals necessitates innovative strategies, especially concerning the transformation of coal-fired power plants (CFPPs). Since they are the primary source of greenhouse gas emissions and still account for a large proportion of power generation sources, this paper explores a novel low-carbon gasification conversion planning approach to facilitate a cost-effective transition of CFPPs. Moreover, a comprehensive two-stage generation expansion planning (GEP) framework, including coal-to-gas (CtG) conversion, generator retirement, and carbon capture and storage (CCS) retrofit, is introduced. In the first stage, a linear emission reduction target is also integrated as a penalty term in the objective function to maximize emission reduction while avoiding excessive emission reduction costs. Upon completing the first stage, the second stage evaluates the flexibility of these planning schemes by comparing adaptation costs, thereby ensuring a smoother transition. The proposed model is rigorously tested on the IEEE 24-bus and 118-bus systems. The 24-bus system simulation results show that the proposed framework reduces costs and emissions by 26 % and 41 %, respectively, compared to the traditional retirement-only method. Moreover, based on the above framework, the proposed carbon target function can further reduce emissions by 18 %. The effectiveness and flexibility of the proposed framework and models have been verified.