Research Needs for the Solid Oxide Electrolyzer (SOEC) with a Proton-Conducting SOEC (H-SOEC) Electrochemical Hydrogen Compressor (EHC) Energy Conversion Network (ECN)

Abstract

A high temperature solid oxide electrolysis cell (SOEC) for electrolysis of water is paired with a H-SOEC for hydrogen compression (EHC). SOEC and EHC have been integrated into an electrochemical network (ECN) in a flow-series configuration and then simulated and analyzed. Adding heat and minimizing area specific resistance (ASR) would be highly desirable for further developing highly-efficient SOEC+EHC ECN’s. It is important to note there is a maximum possible heat generation rate with a given ASR when operated below the thermoneutral point. There is a maximal heat addition rate for optimal efficiency of the SOEC, and it is not at thermoneutral. Many developers have expressed interest in the thermal management of electrolyzer cells and in the possible existence of such an optimum. It is important to understand in general that heat removal can allow an increased hydrogen production rate over the thermoneutral path at constant temperature. For this reason, the SOEC+EHC ECN was simulated over a range of currents and ASR’s to determine the heat addition or removal required. If the internal resistance of an SOEC could be lowered sufficiently via the development of new, high-performing materials, the efficiency of hydrogen production could be very high, especially when supplementary heat is provided from solar or other waste heat sources such as nuclear or coal power plants. It is remarkable that a quarter to a third of the energy for the combined high-temperature electrolysis and hydrogen compression system could be provided by solar, nuclear, or coal.