Operational characteristics of high-pressure, high-efficiency water-hydrogen-electrolysis

After more than 5000 hours of operation of the 100-kW-Pilot-Electrolyzer developed by the Gesellschaft fur Hochleistungselektrolyseure zur Wasserstofferzeugung mbH (GHW) the experience accumulated so far allows the scale up to the Megawatt size of this high pressure electrolysis. Several operational concepts ranging from constant current long time tests over solar photo voltaic energy storage to subsecond compensation of power plant network fluctuations have been successfully simulated. The response of the main system parameters during these simulations are described. For partial load operation the normally increased hydrogen percentage in the produced oxygen has been stabilized by a special liquor circulation control. The material problems like corrosion under extreme conditions are solved up to now. Some of the material aspects are discussed. As measurement and control techniques are the backbone of the safety system sensors and signal processing are briefly mentioned. The single cell voltage measurement is explained. In total, the gained knowledge allows the design of this kind of electrolyzers for wherever its use is technically and economically attractive. The decreasing acceptance of air pollution improves the position of electrolysis. Beginning with an overview on high-pressure electrolyzers actually realized an outlook to coming projects and future applications is given.