High temperature electrolysis
In contrast to low temperature water electrolysis \cite{Seibel_2018}, high temperature electrolyzers \cite{Xing_2018} are operated in the range from 700 to 900°C . Harnessing the heat of vaporization (see Fig. \ref{138375}), the total energy demand for hydrogen production based on a process directly fed with water steam is 35% lower than it is for conventional electrolysis \cite{verfondern2007nuclear}.