Optimal configuration and pressure levels of electrolyzer plants in context of power-to-gas applications

The analysis exemplarily focuses on hydrogen delivery pressures between 1 and 100 bar and an aimed maximal water content of 5 μmol/mol, as required e.g. for automotive applications. The results show that the energy demand for drying dominates the total energy balance at low delivery pressure. Higher electrolyzer pressures increase the losses due to hydrogen crossover. A mechanical compression prior to drying can be used to reduce the overall energy demand of the process. The electrolyzer pressure can be kept below 20 bar, which reduces hydrogen crossover and besides enables anyhow efficient drying at high pressures.