Techno-economic analysis of high-power solid oxide electrolysis cell system

Abstract

Water electrolysis using solid oxide electrolysis cells is a promising method for hydrogen production because it is highly efficient, clean, and scalable. Recently, a lot of researches focusing on development of high-power stack system have been introduced. However, there are very few studies of economic analysis for this promising system. Consequently, this study proposed 20-kW-scale high-power solid oxide electrolysis cells system configurations, then conducted economic analysis. Especially, the economic context was in South Korea. For comparison, a low-power system with similar design was used as a reference; the levelized cost of hydrogen of each system was calculated based on the revenue requirement method. Furthermore, a sensitivity analysis was also performed to identify how the economic variables affect the hydrogen production cost in a specific context. The results show that a high-power system is superior to a low-power system from an economic perspective. The stack cost is the dominant component of the capital cost, but the electricity cost is the factor that contributes the most to the hydrogen cost. In the first case study, it was found that, if a high-power system can be installed inside a nuclear power plant, the cost of hydrogen produced can reach $3.65/kg when the electricity cost is 3.28¢/kWh and the stack cost is assumed to be $574/kW. The second case study indicated that the hydrogen cost can decrease by 24% if the system is scaled up to a 2-MW scale.