Why is sustainability in water management so important in the context of the energy transition?

Ilka Gehrke: To answer that, I would like to briefly touch on classic power plant technology, which relies on fossil fuels. It requires a great deal of water and is essentially responsible for the fact that more than half of all water withdrawal in Germany is attributable to energy production, primarily for cooling purposes. However, most of this water is not consumed but returned to the water cycle. The situation is different in the planned Greens hydrogen economy. Although this requires less water, it is converted into hydrogen and oxygen by electrolysis and consumed accordingly.

So special location requirements are needed for hydrogen production?

Ilka Gehrke: Exactly. The hydrogen economy requires sufficient water availability, both in terms of quantity and quality. Naturally, this is not the case everywhere in Germany. Nevertheless, water is currently hardly an issue in the selection of locations. Take, for example, the planned hydrogen hubs in northern Lower Saxony. Capacities of several GW are planned here, which corresponds to a good part of the National Hydrogen Strategy of 10 GW of domestic electrolysis capacity by 2030. The limits of the water supply could be reached or even exceeded here if drinking water alone were to be used. In addition to extraction from rivers, other alternative water sources such as sewage treatment plant effluent are therefore being considered. However, the treatment of this water to produce industrial water produces concentrates containing salts and various other chemicals. Their discharge is the subject of controversial debate. Or let's look at the chemical site in Leuna near Bitterfeld. A hydrogen hub is being built there to supply companies at the location with green hydrogen. The fact is that the local drinking water in one of the driest areas of Germany is not sufficient to operate the planned expansion stages.

How long have you been involved in the topic of water supply for the hydrogen economy?

Ilka Gehrke: I started looking into this a few years ago. The first project and initial research were launched as part of the DYNAFLEX high-performance center^® . We then bundled the topics on a website called "WHy: Water for the Greens Hydrogen Economy," prepared information, and created maps showing the planned hydrogen locations in connection with the aridity index. At the same time, there were more and more inquiries from politicians, so we launched the EnAqua Dialogue project last year.

What exactly is the goal of the EnAqua Dialogue?

Ilka Gehrke: Our goal is to identify and analyze conflicts of use in the water supply for a Greens hydrogen economy and to find solutions in new dialogue formats. This initially involves identifying all stakeholders and their needs. In addition to the hydrogen economy and water supply, these include local authorities, citizens, agriculture, industry, nature conservation organizations, and associations.

We are also looking at two different model locations in detail so that we can evaluate conflicts directly and identify appropriate measures: Emden in East Frisia, where the electrolyzer will be located in an urban environment, and Arnsberg in the Sauerland region, where the annex will be built in a rural area. We have conducted stakeholder analyses and interviews with the players at both locations. The stakeholders are now coming together in several workshops and digital discussion rounds. Together, we are developing scenarios and concepts for resolving existing and potential conflicts. The scenarios relate to different time horizons and take into account constraints such as the water situation, climate change, and regional development.

How is the EnAqua Dialogue project consortium structured?

Ilka Gehrke: Fraunhofer UMSICHT is leading the project and providing scientific input. Then there is EPC non-profit limited liability company, which will develop the dialogue process, and IZES Institute für Zukunftsenergie- und Stoffstromsysteme non-profit limited liability company, which is responsible for the interviews, supporting the workshops, and transferring the results, among other things.

Is it still possible to join the dialogue?

Ilka Gehrke: The EnAqua Dialogue website has recently gone live. There is a form there where interested parties can register for the participation process. So yes, it is still possible to join. The first workshops are exclusively for experts, allowing stakeholders to exchange technical information in a confidential setting. The next round will consist of transfer workshops, which are open to anyone interested. Anyone can register and contribute their opinion. That is exactly what we need.

How difficult is it to get the different interest groups to sit down at the same table?

Ilka Gehrke: That depends greatly on the respective player and the local conditions. In Sande, for example, where an electrolysis plant with a capacity of up to 2.4 GW is to be built in the future, citizens are concerned about their water resources. This is despite the fact that the maximum 3 million m³ of water required annually will be sourced from alternative water sources such as sewage treatment plant effluent. NABU has prepared well in terms of content and sent a long list of questions to the local water association and the responsible energy supplier. In general, NABU and many citizens are calling for more transparency and participation. Local authorities want to avoid controversy surrounding the topic of hydrogen as much as possible and are therefore still relatively quiet for the most part. There is a certain amount of uncertainty among water authorities and associations that water cannot always be provided in sufficient quantities. On a positive note, many operators of hydrogen sites are aware of the issue and relatively open to discussion. Unfortunately, communication with several manufacturers of electrolysers is still very difficult.

The EnAqua dialogue has been running for a good year now. What results do you expect?

Ilka Gehrke: For the Emden location, I expect a lively discussion and exciting concepts. This is already becoming apparent from the interviews we have conducted. Ideally, we will end up with a consensus on the next steps – and greens hydrogen can be produced in an economically and environmentally sustainable way. In Arnsberg, planning for the location is not yet as far advanced. In addition, the water situation there is more favorable. Here, the direction the dialogue will take is still largely open.