Water electrolysis supplied by renewable energy is the foremost technology for producing “green” hydrogen for fuel cell vehicles. The ability to follow rapidly an intermittent load makes this an ideal solution for grid balancing. To achieve large-scale application of PEM electrolysers, a significant reduction of capital costs is required together with a large increase of production rate and output pressure of hydrogen, while assuring high efficiency and safe operation. To address these challenges, a step-change in PEM electrolysis technology is necessary. The NEPTUNE project develops a set of breakthrough solutions at materials, stack and system levels to increase hydrogen pressure to 100 bar and current density to 4 A⋅cm-2 for the base load, while keeping the nominal energy consumption <50 kWh/kg H2. The rise in stack temperature at high current density will be managed by using Aquivion® polymers for both membrane and ion exchange resin. Aquivion® is characterised by enhanced conductivity, high glass transition temperature and increased crystallinity. Dramatic improvements in the stack efficiency will be realised using novel thin reinforced membranes, able to withstand high differential pressures. An efficient recombination catalyst will solve any gas crossover safety issues. Newly developed electro-catalysts with increased surface area will promote high reaction rates. The novel solutions will be validated by demonstrating a robust and rapid-response electrolyser of 48 kW nominal capacity with a production rate of 23 kg H2/day. The aim is to bring the new technology to TRL5 and prove the potential to surpass the 2023 KPIs of the MAWP 2017. The proposed solutions contribute significantly to reducing the electrolyser CAPEX and OPEX costs. The project will deliver a techno-economic analysis and an exploitation plan to bring the innovations to market. The consortium comprises an electrolyser manufacturer, suppliers of membranes, catalysts and MEAs and an end-user.
