Efficiency of solid oxide water electrolysis system for hydrogen production

Water electrolysis coupled with an efficient and clean primary energy source is an ideal large-scale hydrogen production technology.A model was developed to predict the efficiency of a water electrolysis system for hydrogen production based on the overall efficiency of an alkaline electrolysis system,a solid polymer electrolyte(SPE) system,and a solid oxide electrolysis cell(SOEC) system.The results show that both the electrolysis efficiency,56%,and the overall efficiency,25%,are very low.The electrolysis efficiency,76%,of the SPE system is improved,the overall efficiency,35%,is still low.However,the electrolysis efficiency of the SOEC is more than 90% and the overall efficiency is over 55%,both are much higher than the other systems.The overall efficiency of a high-temperature gas-cooled reactor coupled with an SOEC system is the highest among all existing water electrolysis systems.