Economic performance of an SOFC combined system with green hydrogen methanation of stored CO2

As the deployment of renewable energies increases, the development of power sources needed to adjust the supply-demand balance plays an important role. This study investigates a solid oxide fuel cell combined cycle (SOFC-CC) system with carbon dioxide capture, utilization, and storage (CCUS) that adopts green hydrogen methanation of stored CO2. The proposed system has high power generation efficiency and does not contribute to global warming because the CO2 emitted during operation is captured after separation, stored in carbon capture and storage, and converted into a synthetic fuel by methanation. However, because the economic feasibility of SOFC-CC with CCUS is unknown, the discounted cash flow method, which is used in the Projected Cost of Generating Electricity report, is used in this study. For a scenario with a 750 MW rated output, 25 MW photo-voltaic capacity, and 3% discount rate at a unit electricity sales price of 0.36 USD/kWh, the simple integration balance, net present value, and dynamic payback periods are 9, 10, and 12 years, respectively. Therefore, the proposed system is economically viable.