Decarbonizing the power system by co-planning coal-fired power plant transformation and energy storage

The integration of variable renewable energy (VRE) and the gradual phase-out or functional transformation to coal-fired power plants (CFPP) are two essential transition pathways in achieving the carbon neutrality in China. However, the withdrawal of a large amount of CFPPs may lead to the reduction of inertia and the deficiency of flexibility in power systems, as a flexible alternative, energy storage is playing an increasingly important role in leveling fluctuant VRE output. Therefore, this paper proposes a co-planning approach to the CFPP transformation and battery energy storage system (BESS) accompanying with VRE integration. Two options are considered in the transformation path of CFPPs: retirement or reconstruction. Carnot battery, a novel thermal storage reconstruction scheme, is proposed for CFPP reconstruction, which is then comprehensively compared with BESS in terms of technical, economy and CO 2 emission reduction. To ensure the frequency stability in the power system low-carbon transition, the frequency security constraints considering the fast frequency response provided by BESS is embedded in the co-planning model. In addition, the uncertainty of VRE is considered through a robust optimization method. To efficiently solve the problem, the nested column-and-constraint generation (C&CG) algorithm is employed. The case studies are implemented on the IEEE test system and the Shanxi Power System in China. The results show that the co-planning of CB reconstruction to CFPPs and BESS can promote carbon emission reduction and VRE generation accommodation, ensure operation security of decarbonized power systems. Some generation transition paths for decarbonizing the Chinese Power System are suggested in the end.