Solid oxide electrolyser cell

Electrolysis uses electricity to split water into its basic components (H2 and O2). Solid oxide electrolysers (SOEC) are electrochemical systems operating at high operating temperatures (600-900C), allowing the splitting of steam into hydrogen (H2) and oxygen (O2), by use of a ceramic solid oxide membrane across which O2- ions formed in the cathode (fuel electrode) along with H2, are transported towards the anode (air electrode) to complete the electrolytic process. This is the most efficient way to produce hydrogen as the HT-process is using direct steam conversion but has not yet reached commercial scale yet. They are also less flexible than PEM electrolysers regarding start/stop system conditions. SOEC technology can load follow very well and with a very rapid response however, they need to operate in a "hot idle" mode when at 0% load. The SOEC operating conditions requiring an initial source of heat (such as waste heat, bioenergy or nuclear energy), means they may be well attractive for co-location and integration with other industrial or chemical processes.
Lower temperature SOEC (i.e. 500 to 600C) has the advantage of using metal-supported cells leading to lower costs and higher robustness.