High-Pressure PEM Water Electrolysis System

Proton exchange membrane water electrolysers (PEMWE) offer several benefits over the more mature alkaline water electrolysis technology, including its dynamic range and the ability to operate at higher current densities and pressures. The latter is important to curtail the energy- and cost intensive downstream mechanical compression processes, in particular the first stages. High-pressure electrolysers compatible with, e.g., direct injection into chemical industry and gas networks means the mechanical compressor can be eliminated altogether and that the LCOH is significantly reduced. To unlock the potential of high-pressure water electrolysis, however, more R&D is required to improve the stack and system efficiency, durability, and capital expenditure.

A flexible PEMWE system platform for testing of high-pressure prototype stacks with H₂ delivery pressures up to 200 bar and capacities up to 33 kW has been installed at Institute for Energy Technology (IFE) in Norway. 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 for the water electrolyzer system, and to emulate different loads (e.g., grid load profiles, wind generation).

The one-of-a-kind high-pressure (≤ 200 bar_H2) PEMWE test facility at IFE is very well suited to study performances of next-generation stacks and systems, and to tailor and test control strategies that safeguards the system and maximizes efficiency and durability when operated with renewable energy-based intermittent power.