A new concept for electrolyser set to bring Romania and the EU closer to hydrogen targets

Romania is a major player in Eastern Europe, being the most populous country after Poland and one of its largest economies. Romania is also a highly industrial country, with the sector producing almost 30% of the nation’s GDP. To decarbonise its industry, Romania will be in high need of hydrogen in the future: still, the country has yet to catch up. Its official hydrogen strategy has only come around these years, developed in the scope of Romania’s National Recovery and Resilience Plan. According to its provisions, the country will target the construction of electrolysers capacity of at least 100 MW by the end of 2025, producing at least 10,000 tonnes of hydrogen per year. At the same time, studies based on the EU “Fit for 55” package proposals on hydrogen use show that an electrolysis capacity between 1,470 MW and 2,350 MW should be installed in Romania by 2030.

In this sense, the participation of the Universitatea Politehnica Timișoara in the consortium of the project “PRETZEL - novel modular stack design for high PREssure PEM water elecTrolyZer tEchnoLogy with wide operation range and reduced cost” can be seen as an important step towards the development of a hydrogen ecosystem in Romania. The project’s main goal was to develop a new technology for Proton exchange membrane electrolysis (PEMEL), indicated by the EU through its Fuel Cells and Hydrogen Joint Undertaking (FCH JU) programme as the “preferred technology” for the future. The reason is that PEMEL facilities, at the dawn of the project, could not reach the goals set by the FCH JU in terms of cost, efficiency, lifetime and operability.

From its beginning, the project had two main challenges to solve: first, the capital expenditure (CAPEX) reduction through the reduction of critical raw materials use, and second, the increase of the operating pressure to reduce mechanical compression requirements. The PEMEL technology was treated as an up-and-coming hydrogen production system, competing with alkaline electrolysers. These enjoy reduced implementation costs, not only due to higher system efficiency but also to the possibility of operating at higher pressure. To catch up, PEMEL technology needed to demonstrate the ability to reduce raw materials deployment through high production rates at reasonable cell voltage. In addition to solving these issues, the PRETZEL concept also took care of stack components such as the membrane electrode assembly (MEA), the porous current distributor (PCD) and the bipolar plates to be mass- produced and designed with cost-saving measures.

An example is the development of pole plate corrosion protection design: different approaches for corrosion protection at the oxidizing environment present at the anode side of polymer electrolyte membrane (PEM) electrolysers were discussed in the consortium. The simplest solution, a thin titanium foil was taken as a fallback option due to the additional contact resistance between the foil and the copper pole plate. Also, the ultimate goal was to create a corrosion-protective layer for the copper pole plates without the need for precious metals. This way, a structure was developed with niobium as a protective layer combining both desired properties for stability and conductivity. With a Nb-multilayer applied by vacuum plasma spraying, the coating showed excellent stability, as validated by several corrosion measurements. The Universitatea Politehnica Timișoara played a key role in this process, being dedicated to the evaluation of corrosion resistance and leading the work on compliance testing and characterisation.

By looking at the project results, it could be safely stated that it succeeded. A fundamental goal was to “design and manufacture a 25 kW PEMEL stack that reaches an operating temperature of 90°C, pressure of 100 bar and current density of 4 A/cm² (6 A/cm² in overload mode) while maintaining above 70 % efficiency and fast system response times”. The target was reached, as testified by the development of several PEMEL components and a stack design based on hydraulic compression. The project implemented a patented design approach based on hydraulic cell compression, allowing for large planar cell components and effective cooling at very high production rates and temperature levels. These results have since been published in scientific journals, and, most importantly, the innovations produced have successfully made their way over to the commercial world, putting Romania on the roadmap of hydrogen development.

UPT is further actively involved in several other PEMEL research initiatives. One of them is the “CoDe-PEM - Combinatorial Design of Novel Bipolar Plate Coatings for Proton Exchange Membrane Electrolyzers” project, a partnership with SINTEF Industry Norway funded by the EEA Grants 2014–2021 (EEA RO-NO-2018-0502), aiming to contribute towards the development of affordable PEMEL systems by creating less expensive coating materials for bipolar plates and sinters.

Participation in the PRETZEL project brought UPT the perspective of collaborating in a consortium with experts from research institutes, small and medium enterprises and also large industrial partners. UPT shared its expertise in materials testing and characterization, developing new testing protocols for the corrosion resistance of materials used in PEMEL. Working in a highly motivated and efficient team provided the university with many benefits, including access to a wide range of expertise and opportunities for networking and collaboration, leading to new research ideas, joint publications, and potential for future collaborations. These are essential factors for a higher education institution to stay at the forefront and have a significant impact in advancing knowledge.