Abstract
This work presents the techno-economic analysis of the Solid oxide semi-closed CO2 cycle (SOS-CO2), a hybrid sem-iclosed cycle with solid oxide fuel cells (SOFC) recently de-veloped by Politecnico di Milano for power generation from natural gas with high efficiency and near-zero CO2 emis-sions. All the cycles components, including the fuel cell and the turbine, have been designed and sized with the aim of assessing the performance and the capital cost. The performance and the economic key performance indicators are compared with those of two benchmark technologies for power generation with CO2 capture: the Allam cycle and a combined cycle equipped with ammines for post-combustion capture. Moreover, a sensitivity analysis is performed on the cost of the natural gas and the SOFC stacks. The results indicate that the specific total capital requirement of the SOS-CO2 cycle (2500 €/kWel) is higher than the Allam cycle (1930 €/kWel) and combined cycle with post-combustion capture (1980 €/kWel). On the other hand, the SOS-CO2 cycle benefits from its higher efficiency (74.0% vs. 53.9% of the Allam cycle and 52.8% of the combined cycle) which makes the cycle less sensitive to the fuel cost and CO2 tax. In terms of cost of electricity, the SOS-CO2 cycle turns out to be the best technology for natural gas prices above 8 €/GJ, while the Allam cycle appears to be the preferred option at lower fuel prices. For a fuel cost of 12 €/GJ, the SOS-CO2 features a cost of electricity of 106.2 €/MWh, lower than the Allam cycle (119.1 €/MWh) and the NGCC (126.9 €/MWh).
