Green hydrogen is considered to be an important part of the global climate transition, especially as a fuel and energy carrier for heavy transport and industry. However, large-scale green hydrogen production requires sustainable ways of managing water resources to avoid giving rise to water shortages and conflicts with agriculture over access.

This has been shown in a study from Chalmers University of Technology in Sweden, that connects local water supply with a range of scenarios for future hydrogen needs in Europe.

Replacing fossil fuels with hydrogen in the heavy-duty automotive and industrial sectors has the potential to greatly reduce emissions of the greenhouse gas carbon dioxide. This is especially true if the hydrogen gas is “green”, meaning that it is produced by electrolysis, a process whereby water is spit into hydrogen and oxygen using renewable electricity.

A new study from Chalmers shows that planning where hydrogen will be manufactured, and the use of new technology solutions, is vital in order to avoid the large-scale production of green hydrogen leading to local water shortages in some parts of Europe.

In the study, published in Nature Sustainability, the researchers were able to explore different scenarios for how Europe’s hydrogen production might affect water resources, electricity prices and land use in 2050 – a year by which many countries have agreed to reduce their carbon emissions, which could mean the widespread use of hydrogen technology.

“Water is a resource that is often taken for granted in the energy transition. 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. This is because it’s better to produce hydrogen in close proximity to industry and access to renewable electricity, which generally means areas where water resources are already under strain.

“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,” says Joel Löfving, doctoral student at the Division of Transport, Energy and Environment at Chalmers.

Sörmland and Roslagen are high-risk areas

If hydrogen starts being widely used in industry and transport, the water supply might be severely impacted in multiple regions if the choice is to produce hydrogen locally, which is advantageous for economic reasons. For Sweden, it is anticipated that the water supply in the Sörmland and Roslagen regions, for example, is going to be hard pressed even without hydrogen production in 2050.  

“In Sörmland there is already a steel mill and a refinery. If they were to switch to hydrogen and use local water sources to produce it, this could exacerbate the projected water shortage. Also, in the Roslagen region northeast of Stockholm, we can see that it might be difficult to source local water for the production of green hydrogen, and in the Bohuslän 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 per cent. Although the water supply there is considered to be good, there is a risk that this production could have a significant impact on the natural environment,” he says.

The study analysed over 700 local water sub-basins in Europe, and similar patterns to those seen in Sweden could be identified in multiple locations. In southern and central Europe, where favourable conditions for generating electricity with solar and wind power make green hydrogen production particularly attractive, access to water is estimated to be very limited by 2050, as local water resources are already under strain and vulnerable to climate change. Major industry clusters in Spain, Germany, France and the Netherlands, for example, could thus face a conflict with agriculture, for example, over water resources.

“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. There are also interesting synergies, as the oxygen that remains from the hydrogen production could be used in the processes that treat the wastewater. Hydrogen has great potential to contribute to the climate transition, but we need to find sustainable ways to manage water resources – for the production of fuel and for agriculture,” says Löfving.

Electricity prices impacted less than expected

In addition to water use, the researchers studied how a large-scale hydrogen economy could affect Europe’s electricity prices. By plugging the hydrogen model into Chalmers’ Multinode model – a model developed for optimising the costs of Europe’s energy system in different scenarios – they were able to estimate changes in electricity prices between different regions.

The results show that electricity demand increases significantly in line with the amount of hydrogen produced, since it takes a lot of electricity to replace the energy in fossil fuels. Despite this, the results show that the impact on average electricity prices in Europe is relatively small.

In regions with good access to renewable energy sources, such as northern Europe, the price impact is the smallest. In southern Europe, where some regions are dependent on a higher proportion of electricity from gas or nuclear power, for example, bigger price increases were seen.

“Electricity prices are a sensitive issue, but our modeling shows that increased investment in electricity production for producing hydrogen does not necessarily lead to higher prices for consumers. This is an important message to decision-makers – to cope with the energy transition, all fossil-free energy sources are needed, and we must have the courage to invest in new, green electricity production,” says Löfving.

Broad patterns and local consequences

Large-scale green hydrogen production would require a big expansion of solar and wind power. But the expansion would only take up a few per cent of the land currently used for agriculture, according to the study. And this area is significantly less than would be required to replace the same amount of energy with biofuels.

The researchers argue that, taken together, the results provide an important holistic perspective on Europe’s energy transition. Previous studies have often focused on either local effects or effects at overarching system levels, but rarely combined both.

“It was this connection that we wanted to make. If we are going to build the future’s energy system, we need to understand both the broad patterns and the local consequences. By considering risks, we will be able to manage them and thus create more certainty for investments in green technology,” says Löfving.

Green hydrogen

Produced by electrolysis when water is split into hydrogen and oxygen using electricity. The electricity used must come from renewable sources such as solar, wind or hydro power for the hydrogen to be labelled “green”.