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 German Energy Agency DENA reports that the ENERGY HUB Port of Wilhelmshaven – an association of more than 30 companies – plans to produce 194 tons of hydrogen per hour by 2031 using electrolysis. That's equivalent to 6.51 gigawatts of power. In total, according to the DENA report, the amount of water required at times of maximum consumption by all the planned plants adds up to at least 4,861 metric tons per hour in 2031[2]. By way of comparison, the largest water association near Wilhelmshaven – the Oldenburg-Ostfriesische Wasserverband OOWV – delivered an average of 9,475 metric tons of water per hour to its 928,668 customers according to its 2021 annual report[3]. During peak times of the ENERGY Hub, it would be as if the OOWV had to additionally supply a large city with half a million inhabitants with water; in a region where water use is already limited at times.
So far, the water strategy of the Federal Ministry for the Environment, Nature Conservation, Nuclear Safety and Consumer Protection (BMUV)[4] and the energy strategy of the Federal Ministry for Economic Affairs and Climate Action (BMWK)[5] have stood side by side without any interconnection. Since responsibilities and legal framework conditions have not been clarified, this results in planning uncertainty for all 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[6] 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 extreme drought and water scarcity at the present time? Some regions are rightly concerned, as a study evaluating hydrogen sites in Lower Saxony shows[7]. For the district of Leer, for example, it advises against extracting water from groundwater.
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.
Global methanol production amounted to 110 million tons in 2018[8]. The compound is essential as a solvent, relevant for fuel production and as an educt in the synthesis of various substances. These include, for example, formaldehyde or adhesives. Methanol has so far mainly been produced from fossil raw materials such as natural gas or coal. In the Carbon2Chem® research project, methanol is synthesized from metallurgical gases instead, which both reduces the carbon footprint of steel production and opens an alternative methanol source.
Investigations within the joint Carbon2Chem® research project have shown that the aqueous fraction (wastewater) from methanol synthesis offers huge potential for hydrogen production – as feed for electrolysis. While the wastewater serves as an alternative water source, the hydrogen produced can be reused for methanol synthesis, thus reducing the carbon footprint.
Fraunhofer UMSICHT has developed a learning unit on water use in the hydrogen economy for the interdisciplinary continuing education program DYNERGY. The focus of the learning unit is on green hydrogen, putting the water situation in Germany into the context of hydrogen production. In addition, resource conflicts in the field of tension between water and energy transition are characterized, and solution-focused strategies are shown. The learning unit ends with an outlook on international conflicts of goals.
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[9]. 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[10].
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.
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 89 hydrogen projects of various planning phases can be researched in Germany (as of September 2024). 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 11.4 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.
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. |
[1] https://www.bmbf.de/bmbf/de/forschung/energiewende-und-nachhaltiges-wirtschaften/nationale-wasserstoffstrategie/nationale-wasserstoffstrategie_node.html
[2] https://www.wirtschaft-wilhelmshaven.de/assets/images/Pressemitteilung_Anlage_1.pdf
[3] https://geschaeftsbericht.oowv.de/de/2021/zahlen-und-fakten
[4] https://www.bmuv.de/wasserstrategie
[5] https://www.bmwk.de/Redaktion/DE/Publikationen/Energie/energieeffiezienzstrategie-2050.pdf
[6] Saravia et al. 2023 (h2o-fuer-elektrolyse-dvgw-factsheet.pdf)
[7] Eggers 2022
[8] 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.
[9] Cullmann, Astrid; Sundermann, Greta; Wägner, Nicole; Hirschhausen, Christian von; Kemfert, Claudia (2022): Wertvolle Ressource Wasser auch in Deutschland zunehmend belastet und regional übermäßig genutzt.
[10] 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