As the urgency to decarbonize the industry and transport sector intensifies, renewable energy-based hydrogen production via advanced low temperature water electrolysis is attracting increased interest. Proton exchange membrane water electrolysers (PEMWE) offer several benefits over the more mature alkaline water electrolysis technology, including its load-following capability and the ability to operate at higher pressures. The latter is important because significant benefits can be harvested by adopting systems operating at pressure-levels compatible with the end use applications and thereby render the mechanical compressor redundant. At IFE we have developed a methodology which encompasses detailed energy- and techno-economic calculations of high-pressure systems, and a comparison between high-pressure electrolysis and state-of-the-art electrolysis at 30 bar in combination with a compressor has been carried out. Here, direct pressurization to 80 and 200 bar (relevant for, e.g., methanol and ammonia production) was found to be economically viable.

To realize high-pressure H₂ generation systems, many challenges related to system operability, efficiency and safety needs to be addressed. As part of the national infrastructure “The Norwegian Fuel Cell and Hydrogen Centre”, Institute for Energy Technology (IFE) has installed a flexible PEM water electrolyzer system platform for testing of small-scale prototype electrolyzers up to 33 kW and 200 bar differential pressure. The test rig is integrated with a sophisticated power conditioning system which consists of three custom-built DC/DC-converters (for PEMWE, PEMFC, and Li-ion battery systems), all coupled to the same DC-bus. This configuration makes it possible to test different hybrid electric topologies and to emulate different loads (e.g., grid load profiles, wind generation). This one-of-a-kind high-pressure PEMWE test facility at IFE is well suited to study performances of next-generation PEMWE stacks and systems, and to tailor and test control strategies that safeguards the system and maximizes efficiency and durability

The test rig has been commissioned with a prototype high-pressure stack with a production capacity of 2 Nm3/h (Nel Hydrogen), and the identified economically viable pressure range of 80-200 bar has been the main target for an experimental test campaign. The experimental results are presented from stack testing including polarization curves and EIS data as a function of temperature, pressure and current density. The results are discussed in relation to the techno-economic model, in order to identify pathways towards more efficient hydrogen production.