Green hydrogen will not be automatically green unless national power grids decarbonise at pace, new research warns.
A study led by the University of Sheffield and published in Nature Communications Sustainability finds that the emissions profile of hydrogen depends heavily on how the electricity used to produce it is generated.
Without cleaner grids, so-called green hydrogen risks carrying a significant carbon footprint.
The research team, led by Professor Lenny Koh, modelled 20 scenarios for producing and transporting hydrogen across 14 countries between 2023 and 2050, including the UK, US, China, Japan and several European states.
They assessed five production pathways, three using electrolysis and two using biomass, reflecting the main technologies in use today.
In 2023, electrolysis-based hydrogen showed the highest global warming impacts. The process is energy-intensive and where electricity comes from fossil fuel-heavy grids the environmental gains are eroded. Manufacturing and maintenance of equipment also add to the footprint.
However, the outlook shifts over time. The study suggests proton exchange membrane electrolysis could become the most sustainable option by 2050, provided the electricity feeding it comes largely from renewable sources.
Under cleaner grid scenarios, some hydrogen supply chains could cut greenhouse gas emissions by more than 90% compared with current production methods.
One of the strongest long-term scenarios involves hydrogen manufactured in the UK using proton exchange membrane technology and exported to the US, assuming both countries meet their clean energy ambitions.
Copyright © 2026 Energy Live News LtdELN