Europe's Green Hydrogen Ambitions Face an Overlooked Obstacle: Local Water Supply
The European hydrogen economy faces a hidden complication that energy transition models frequently overlook: water.
Green hydrogen - produced by splitting water using electricity from renewable sources - requires the one input that energy planners rarely treat as a constraint. A liter of water per hundred grams of hydrogen is a rough approximation of the chemistry, but at continental scale, across decades of ramp-up, the cumulative demand interacts with geography in ways that matter considerably.
A study from Chalmers University of Technology in Sweden, published in Nature Sustainability, makes that interaction visible for the first time in a framework that connects European-level hydrogen scenarios to local watershed stress in more than 700 river basins across the continent.
Where hydrogen production wants to go
The economic logic of hydrogen production has a spatial logic: produce it where renewable electricity is cheapest and where industrial demand is highest. Those two factors point toward the same regions - coastal areas with wind resources, southern Europe with strong solar potential, and existing industrial clusters in Germany, the Netherlands, France, and Spain.
They are also, frequently, the same areas where water resources are already under strain. Agriculture in southern Europe competes intensively for the same surface and groundwater that hydrogen electrolysis would require. Northern industrial clusters sit in watersheds that are projected to face tighter water budgets by mid-century even without new demands from the energy sector.
"Water is a resource that is often taken for granted in the energy transition," said Joel Lofving, doctoral student at Chalmers' Division of Transport, Energy and Environment. "Our study is unique because we have connected the local perspective to the European perspective. We can show that even if hydrogen production does not require very much water in total compared to say agriculture, the local effects can be significant."
Sweden as a case study
The paper examines specific Swedish regions in detail. Sormland already hosts a steel mill and a refinery. If either facility transitions to hydrogen-based production and draws on local water sources for electrolysis, the projected water shortage in that region by 2050 becomes substantially worse.
In the Bohuslan region on the Swedish west coast, and parts of Norrland in the north, large-scale hydrogen production could increase water withdrawal by more than 50% relative to baseline. In southern and central Europe, where favorable conditions for solar and wind power make green hydrogen production particularly attractive, access to water is estimated to be very limited by 2050.
"There are many potential conflicts around water as a resource, but also many solutions, such as seawater desalination or the reuse of water from wastewater treatment plants," Lofving said. "There are also interesting synergies, as the oxygen that remains from the hydrogen production could be used in the processes that treat the wastewater."
Electricity prices: less affected than feared
The study also modeled how large-scale hydrogen production would affect European electricity prices. Despite substantially increased electricity demand, the impact on average consumer prices is relatively modest - particularly in northern Europe with strong renewable resource access.
Land use for renewable energy expansion would represent only a few percent of current agricultural land - substantially less than would be required to produce the same amount of energy from biofuels.
"The conclusion is not that hydrogen production should be avoided, but that we must understand different perspectives and cooperate on many different levels - between government agencies, industry and local communities - to plan for the local effects of the transition," Lofving concluded. The study's value lies in the framework it provides for identifying where risks concentrate, not in precise predictions of 2050 outcomes.