Concept and approach

Recent developments in the field of polymer electrolyte membrane electrolyzers (PEMEL) strive towards the reduction of overall system costs in order to compete with state of the art alkaline electrolysis. Major optimization aspects refer to an increase in efficiency as well as the achievement of high-pressure electrolysis. Both issues concern the PEMEL stack, which needs to generate hydrogen with high production rates (high current density) at a reasonable cell voltage (efficiency) and high output pressure so that raw material deployment can be reduced (e.g. noble metals, proton conductive polymers and titanium) and balance of plant components can be omitted (especially, compressor stages).

Schematic drawing of a PEMEL system as container solution by iGas energy.

Furthermore, the stack components such as the membrane electrode assemblies (MEA), the porous current distributor (PCD) and the bipolar plates (BPP) must be mass produced and designed with cost saving measures in mind in order to improve efficiency in use of expensive raw materials.

This concept addresses the above aspects to realize the next generation electrolyzer technology, whilst meeting the needs of industrial scale hydrogen production in the near future. Beyond these challenges, a significant increase of lifetime and improved operability will be achieved to cope with intermittent electricity supply from renewable energy sources.

This approach is encapsulated in the full title of the project: “Novel modular stack design for high PREssure PEM water elecTrolyZer tEchnoLogy’’ with wide operation range and reduced cost. This is shorted to the acronym: ‘’PRETZEL

Concept of PRETZEL project with component inputs and expected outcome.

Each of these innovations have already proven in a small laboratory scale and can be considered being in the range of TRL 3. Hence, the overall goal of this project is to prove the functionality of these proven technologies in a realistic environment in order to advance them to TRL 5. In practice, this means integrating them into a fully functioning 25 kW, 100 bar electrolyzer system that reflects the realistic and highly dynamic conditions required by the market.