NEPTUNE · Next Generation PEM Electrolyser under New Extremes

Water electrolysis supplied by renewable energy is the foremost technology for producing “green” hydrogen forfuel 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 togetherwith a large increase of production rate and output pressure of hydrogen, while assuring high efficiency and safeoperation. To address these challenges, a step-change in PEM electrolysis technology is necessary. The NEPTUNEproject develops a set of breakthrough solutions at materials, stack and system levels to increase hydrogen pressureto 100 bar and current density to 4 A cm-2 for the base load, while keeping the nominal energy consumption <50kWh/kg H2. The rise in stack temperature at high current density will be managed by using Aquivion® polymers forboth membrane and ion exchange resin. Aquivion® is characterised by enhanced conductivity, high glass transitiontemperature and increased crystallinity. Dramatic improvements in the stack efficiency will be realised using novelthin reinforced membranes, able to withstand high differential pressures. An efficient recombination catalyst willsolve any gas crossover safety issues. Newly developed electro-catalysts with increased surface area will promotehigh reaction rates. The novel solutions will be validated by demonstrating a robust and rapid-response electrolyserof 48 kW nominal capacity with a production rate of 23 kg H2/day. The aim is to bring the new technology toTRL5 and prove the potential to surpass the 2023 KPIs of the MAWP 2017. The proposed solutions contributesignificantly to reducing the electrolyser CAPEX and OPEX costs. The project will deliver a techno-economicanalysis and an exploitation plan to bring the innovations to market. The consortium comprises an electrolysermanufacturer, suppliers of membranes, catalysts and MEAs and an end-user.