Parametric technical-economic investigation of a pressurized hydrogen electrolyzer unit coupled with a storage compression system

By considering on-site hydrogen refueling stations, investigations are still needed on how the integration between electrolysis units and compressors can be better matched by tuning the operating parameters, such as temperature and pressure, and how it could affect the energy consumption and the overall efficiency. This paper presents a comprehensive characterization of a hydrogen production facility, composed of a water-based electrolysis unit, a volumetric compressor, and a storage system, up to 350 bar. Their operation is investigated through a sensitivity analysis: pressure and temperature are used as parametric inputs to forecast the different energy performance of the system in terms of voltage efficiency, stack efficiency, cell voltage, and system efficiency, as well as the influence of the over-voltages. An economic analysis is also presented, to compare the benefits of a high-pressure electrolyzer (up to 30 bar), showing that its installation can lead to important savings, up to 670 k€ of energy saved by a less demanding compression process in 20 years for an electrolysis capacity of 1.5 ton/day.