Green hydrogen (GH₂) is produced through the electrolysis of water in an electrolyser, powered by renewable electricity, e.g., wind, solar, hydro, thermal, (<0.1% of the global hydrogen production versus 99% from fossil fuels). Some recent market reports indicate that between 400 and 550 million tonnes of GH₂ will be produced by electrolysis, requiring 3000–4000 GW of electrolysers (ca. 3000–4000 times increase in electrolyser capacity by 2050).

Water electrolysers and especially low-temperature water electrolyser (LT-WE) technologies strongly depend upon (i) materials used, i.e. catalysts, electrolytes, separators, electrodes, porous transport layers/gas diffusion layers and (ii) working temperatures and pressures. Currently, there are three main types of LT-WE, namely: (i) proton exchange membrane water electrolyser (PEMWE), (ii) alkaline water electrolyser (AWE), and (iii) anion exchange membrane water electrolyser (AEMWE). For all LT-WE, further R&D in materials and systems (e.g. balance of plant) is required to drastically improve efficiency, performance and durability, as well as reducing costs.

This presentation highlights the state-of-the-art, benefits, bottlenecks (e.g. critical raw materials, membranes, degradation, costs), strategies for cost reduction (materials, stack and system levels), potential routes for overcoming the major issues, and key performance indicators and technology targets for all LT-WE technologies.

Bruno G Pollet is a professor of chemistry at the Université du Québec à Trois-Rivières (UQTR), director of the UQTR Green Hydrogen Lab (GH2Lab), deputy director of the UQTR Institute for Hydrogen Research (IHR), and adjunct professor of renewable energy at the Norwegian University of Science and Technology (NTNU). He has worked on hydrogen energy in the UK, Japan, South Africa, Norway and Canada. He holds two prestigious research chairs, the NSERC Tier 1 Canada Research Chair in Green Hydrogen Production, and the Innergex Renewable Energy Research Chair (partly funded by the Quebec Ministry of Economy and Innovation) focusing on the next generation of water electrolysers and hydrogen production technologies. He is also president of the Green Hydrogen Division of the International Association for Hydrogen Energy (IAHE). He was recently invited to join the Council of Engineers for the Energy Transition (CEET): An Independent Advisory Council to the United Nations’ Secretary-General, and awarded the IAHE Sir William Grove Award for his ground-breaking work in hydrogen, fuel cell and electrolyser technologies.

Prof. Pollet completed his PhD in physical chemistry at Coventry University and undertook his postdoc in electrocatalysis at Liverpool University. His research covers a wide range of areas from the development of novel materials for low-temperature fuel cells and water electrolysers, hydrogen production from (non-)pure waters, organics and bio-wastes to fuel cell and electrolyser systems, demonstrators and prototypes. His research also focuses on ultrasound and sonoelectrochemistry to produce fuel cell and electrolyser materials, and to improve electrochemical processes. He is the author of two books, edited more than 17, and published more than 25 book chapters on hydrogen and fuel cells, sonochemistry, and sonoelectrochemisty. He delivered more than 200 keynote and invited talks at various international events.