Exergoeconomic evaluation of an ethanol-fueled solid oxide fuel cell power plant

Abstract

A SOFC (solid oxide fuel cell) system integrated with an ethanol steam reforming unit is evaluated using exergoeconomic analysis. The exergy destruction cost, total production cost, relative cost difference, exergoeconomic factor and thermoeconomic cost of electricity are studied. The TCOE (thermoeconomic cost of electricity) is compared with electricity cost from similar processes and fuels. A sensitivity analysis has been carried out in order to have a good insight into SOFC power plant performance, focusing on ethanol steam reformer temperature (823 < TESR < 973 K), SOFC stack unit cost (1500–400 $ kW) and fuel price (0.002 < ethanol price < 0.01 $ MJ−1). Results suggest that the SOFC unit constitutes the most important component in the process. A reduction in the investment cost and in exergy destruction within the stack may reduce the total production cost (Ctot), total investment costs (Ztot) and exergy destruction cost (CD) by 18%, 73% and 19% respectively, as well as the electricity cost (TCOE) by 21%. The higher production cost corresponds to higher ethanol price, due to the specific exergy cost of streams. In the best scenario, the electricity cost using ethanol as feedstock reaches 0.04 $ kWh−1, which is comparable and competitive with natural gas (0.06 $ kWh−1) using SOFC technology.