Estimating the Impacts of Integrating a Solid Oxide Electrolyser into a Coal Power Plant

Coal plants are under tremendous stress due to the introduction of renewables, particularly solar, which create intermittent periods of power demand and lower the overall demand for coal-based power. For coal plants to operate efficiently and consistently, it has been proposed that solid oxide electrolyser cells (SOECs) be incorporated into the coal plants to produce storable hydrogen from high temperature steam and electricity. An integrated SOEC would enable the boiler to operate at maximum efficiency while borrowing a fraction of the clean high temperature steam for electrolysis. It is likely that the increase in efficiency, consistent operating hours, and revenue from hydrogen sales will outweigh the price of integration, but it is yet unknown whether this solution is profitable. One of the challenges to assessing the profitability of SOEC integration is the variability in coal plant sizes. To assess the profitability of SOEC integration in any sized coal plant, an excel sheet was developed that uses coal plant specifications to calculate coal, water and air consumption, electricity, hydrogen and oxygen production, and expected costs and revenue from each. The sheet also automatically calculates the net present value (NPV) and displays the discounted cumulative cash flow. This excel sheet can be used to model the integration of an SOEC into any selected coal plant, enabling coal plant managers to decide whether or not to invest in the project.