The production of green hydrogen requires large amounts of water, such water being available at the production sites in varying quantities and qualities. Fraunhofer UMSICHT aims to analyze the water situation in individual regions, both in studies and by entering into a dialogue with the actors involved in order to identify and solve conflicts of use. Furthermore, alternative water sources shall be developed by means of new technological processes.
The green hydrogen economy is a key pillar in energy transition. Ambitious expansion targets have been set in the national hydrogen strategy[1] . For achieving these goals, significant additional quantities of water must be extracted at regional level – for example, for the ENERGY HUB Port of Wilhelmshaven.
The ENERGY HUB Port of Wilhelmshaven an association of over 40 companies – aims to produce 34.1 terawatt hours of climate-friendly hydrogen (per year) by 2031 using electrolysis[2]. To produce this amount of hydrogen, 7.72 million cubic meters of water per year are required – excluding cooling water. According to a DVGW study, the cooling water consumption can be up to 25 kg per kilogram of hydrogen produced[3]. By way of comparison, the largest water association near Wilhelmshaven – the Oldenburg-Ostfriesischer Wasserverband OOWV – supplied 79.1 million tons of water per year to its more than one million customers according to its 2023 annual report[4]. In order to supply the ENERGY HUB, the OOWV would have to provide 34 percent more water; in a region where water use is already restricted at times. Despite this, the BMUV's water strategy[5] and the BMWK's energy strategy[6] stand side by side, unconnected. As responsibilities and the legal framework have not been clarified, this results in planning uncertainty at the level of the actors involved.
Some regions focus on green hydrogen technology, and at selected locations, the planning processes for hydrogen hubs are already well advanced. Planning uncertainty can have severe consequences for the parties involved, especially during hydrogen market ramp-up. The German Technical and Scientific Association for Gas and Water (DVGW) describes in a recent study[7] that water resources in Germany are sufficient for the production of green hydrogen. However, is this assumption also plausible to hydrogen sites and regional actors who are already suffering from drought and water scarcity at the present time? Some regions are rightly concerned, as a study evaluating hydrogen sites in Lower Saxony shows[8]. For the district of Leer, for example, it advises against extracting water from groundwater.
The Hydrogen Acceleration Act (WassBG) has also given rise to criticism from some interest groups. The WassBG aims to accelerate the hydrogen transformation in Germany by introducing fast, simplified and digitalized procedures for the planning, approval and awarding of hydrogen projects. The rural population of Lower Saxony fears that their water needs will be given lower priority and expressed this concern last year in an incendiary letter to Lower Saxony's members of parliament.[9]
Together with partners from the humanities and natural sciences, Fraunhofer UMSICHT develops an innovative dialogue process. The process is intended to be implemented in hydrogen model regions with water and energy suppliers, municipalities, and society. In parallel, Fraunhofer researchers prepare studies on the availability, market, costs and maturity of technologies for the treatment of different water qualities for electrolysis. Complete site analyses are also carried out.
Fraunhofer UMSICHT identifies alternative water sources that are not in direct competition with drinking water production and irrigation. These can be, for example, industrial wastewater and treated wastewater from municipal wastewater treatment plants, or brackish water, and other site-specific water sources. To this end, treatment processes are developed from laboratory scale to pilot scale, with the aim of using them for alkaline electrolysis or polymer electrolyte membrane (PEM) electrolysis.
Since the project started in March 2024, several valuable interim results have already been achieved. These range from surveys on the green hydrogen economy to the development of learning units.
Fraunhofer UMSICHT conducted a representative survey in February 2025. The most important finding was that 90 percent of respondents consider the green hydrogen economy to be important for Germany. Fifty-three percent would even support water savings in favor of hydrogen production. At the same time, water is a factor for respondents when it comes to locating hydrogen hubs: 45 percent believe that sufficient water should be available at the hydrogen production site. An overview of the results can be found in this German PDF file. If you are interested in the complete evaluation, please contact Ilka Gehrke.
Whether as a solvent, for fuel production or as a reactant in the synthesis of substances such as formaldehyde or adhesives, methanol plays an important role in many areas. Until now, the compound has been obtained mainly from fossil raw materials such as natural gas or coal. An alternative route is being pursued in the Carbon2Chem® joint research project, where methanol is synthesized from steel production gases. The wastewater produced during this synthesis has great potential for hydrogen production, according to the results of a study conducted as part of WHy. On the one hand, it serves as an alternative water source and can be used, among other things, as feed for electrolysis. On the other hand, the hydrogen produced can be reused for methanol synthesis.
Fraunhofer UMSICHT has developed a learning unit on water use in the hydrogen economy for the interdisciplinary continuing education program DYNERGY. Its focus is on green hydrogen. Specifically, the water situation in Germany is placed in the context of hydrogen production. In addition, conflicts of use in the area of tension between water and the energy transition are characterized and solution strategies are identified. The learning unit concludes with an outlook on international conflicts of interest.
In the course of climate change, water scarcity and water pollution continue to increase. In Germany, too, average temperatures are rising, and hot spells are also becoming more widespread[11]. Due to increased temperatures and reduced precipitation in some regions of Germany, evaporation is increasing. On the other hand, increased runoff in rivers due to climate change induced heavy rainfall events impedes groundwater recharge[12].
Fraunhofer UMSICHT has created a map that shows the planned hydrogen production sites in connection with the dryness index today and in the future. We would like to point out that the data shown on the map originates exclusively from the sources indicated at the hydrogen locations. Only hydrogen projects that have been published are taken into account.
Help us to always be up to date! Please inform us about new or changed site plans. Last update: February 2025
Both the electrolysis technology and the type of water source are decisive for the water requirements of an electrolyser. Minerals must be removed from the water using demineralization systems in order to produce ultrapure water. This is necessary because impurities in the electrolysis process lead to salt deposits on the membranes (with proton exchange membranes PEM) and the electrodes. To produce one liter of deionized water, 1.2 to 1.3 liters of surface water, 1.5 to 1.6 liters of brackish water or 2 to 3 liters of seawater are required. Based on this data, the water consumption of the forecast hydrogen capacities for Germany can be calculated. If only surface water is used as a water source, this results in a water consumption of 9 million tons in 2030 (10 GW) and 63 million tons in 2050 (70 GW). Water use for corresponding cooling water systems is not included here. The cooling system must be selected depending on the site conditions. Among other things, air cooling, which uses a minimum amount of water, once-through cooling with a water requirement of 920 to 2450 kg per kg of hydrogen and minimum water consumption and other cooling water systems are used.
A total of 81 hydrogen projects of various planning phases can be researched in Germany (as of: March 2025). A particularly large number of sites are planned near the coast, which is not surprising given the existing wind farms as suppliers of green electricity. Due to the enormous hydrogen capacities, the availability of water has been critically questioned there for some time. Those responsible are currently discussing alternative options such as the use of treated seawater or wastewater treatment plant effluent.
If the hydrogen hubs located on the map to date are fully realized (on-shore only), they would deliver a total output of 7,9 GW. By way of comparison, the National Hydrogen Strategy calls for the expansion of 10 GW by 2030 and 70 GW by 2050.
In discussions with experts, we have learned that many more locations for hydrogen production are being discussed. However, as the status of these projects has not yet been published, they are not documented on our maps. After updating the data, some hydrogen hubs are no longer included as the projects have been discontinued or no progress has been made in recent years. In some cases, the available data does not match depending on the source. For example, the ENERGY HUB Port of Wilhelmshaven network states planned hydrogen capacities for 2031 that do not correspond to the total hydrogen production published by the individual projects in the network.
We would be pleased to receive information on new citable projects.
When planning a hydrogen hub, the choice of location is of great relevance. The operator must ensure that the chosen location is suitable for production in the long term, as infrastructure expansion must be taken into account in addition to investment in the facilities. Economic considerations such as power supply and infrastructure, technical aspects such as water supply, space requirements and wastewater disposal as well as ecological factors all come into play. The following table shows the main influencing factors that can be used to classify a location. They help to identify a suitable location that is both economically viable and technically and ecologically sustainable.
In the future, climate change is also significant for water as a resource, as it will increase the drought in some regions. Hydrogen hubs that are built in such areas may be undersupplied and no longer be able to deliver their full capacity.
| Main influencing factors | Description |
| Water source | Identification and evaluation of locally available water sources (groundwater, surface water, seawater) for water electrolysis. Perspective: Inclusion of the future effects of climate change on the water source. |
| Water consumption structure | List of regional water consumption types in the study area. Current water consumption balance of agriculture, households, industry and the energy sector as well as future scenarios. |
| Renewable energies | Determination of current and future regionally available renewable energies for electrolysis in the study area and inclusion of expansion scenarios. Examination of the potential for grid-compatible operation of electrolysers. |
| Storage options | Description of the existing and planned long-term and short-term storage options for hydrogen in the study area. The focus is on salt caverns as long-term storage facilities. |
| Transportation routes | Investigation of existing and planned infrastructure for hydrogen transportation and distribution. This includes pipelines, roads, ports and filling stations. |
| Local acceptance potential | Identification of potential customers for the hydrogen as well as the by-products oxygen and heat. These include industry, transportation and buildings. |
The “EnAqua-Dialog” (conception and implementation of an adaptive dialog process for implementation projects using the example of regional hydrogen hubs) is funded by the Federal Ministry of Economics and Climate Protection BMWK (project start March 2024).
TA-WHy (technology assessment of the effects of hydrogen production on the water situation) is funded by the DYNAFLEX® performance center (duration July 2024 to July 2027).
[1] https://www.bmwk.de/Redaktion/DE/Wasserstoff/Dossiers/wasserstoffstrategie.html
[2] https://www.wirtschaft-wilhelmshaven.de/assets/_energyhub/downloads/Potenziale-der-Jade-Weser-Region_Fraunhofer-Projekt-Update.pdf
[3] https://www.dvgw.de/medien/dvgw/leistungen/publikationen/wasserelektrolyse-gesamtwasserbedarf-factsheet-dvgw-web-format.pdf
[4] https://www.oowv.de/assets/media/downloads/gesch%C3%A4ftsberichte/oowv_gb_2023.pdf
[5] https://www.bmuv.de/wasserstrategie
[6] https://www.bmwk.de/Redaktion/DE/Publikationen/Energie/energieeffiezienzstrategie-2050.pdf
[7] Saravia et al. 2023 (h2o-fuer-elektrolyse-dvgw-factsheet.pdf)
[8] https://doi.org/10.15488/13179
[9] Hennies‘ Brandbrief zum Thema Wasserstoffnutzung – Landvolk Niedersachsen Landesbauernverband e.V.)
[10] Araya, S. S., Liso, V., Cui, X., Li, N., Zhu, J., & Lennart, S. (2020). A Review of The Methanol Economy: The Fuel Cell Route. Energies, 13(3), 596.
[11] Cullmann, Astrid; Sundermann, Greta; Wägner, Nicole; Hirschhausen, Christian von; Kemfert, Claudia (2022): Wertvolle Ressource Wasser auch in Deutschland zunehmend belastet und regional übermäßig genutzt.
[12] Auge, Johannes (2020): Klimawandelanpassungskonzept für den Kreis Euskirchen und seine Kommunen. Zwischenbericht. Hg. v. GreenAdapt Gesellschaft für Klimaanpassung mbH und Öko-Zentrum NRW GmbH.
Fraunhofer Institute for Environmental, Safety and Energy Technology UMSICHT