A look into geothermal development and protection of groundwater resources, Netherlands

View over Utrecht from the Cathedral (source: flickr/ Thomas van de Weerd, creative commons)

Alexander Richter 30 Aug 2019

An article published earlier this month in the Netherlands, looks at how geothermal development can coexist with protection efforts on groundwater resources. Published by Waternet of the province of Utrecht in the Netherlands the articles looks at how to evaluate the effect geothermal development could have on water resources. Here a translated version of the article.

With a test drilling for the Lean research project in prospect, the province of Utrecht brought interested parties together with a view to water quality, drinking water protection and other uses in the subsurface. This concerns Warmtebron Utrecht as initiator of the research projects, municipalities, water boards, drinking water companies, environmental services and the province itself. The primary goal: to gather knowledge about the development of geothermal technology near the built environment in relation to the effects on water quality and the possible risks for drinking water extraction.

“Based on the idea:” What is involved in the research and extraction of geothermal heat from the deep subsurface plus the possible effects on water quality? ” we are currently making an inventory of all the questions and then looking for the answers ”, says Youri den Otter, senior policy officer soil and subsurface at the province of Utrecht. “The focus is on regional knowledge development on geothermal heat in relation to water quality, but other topics such as fractures in the subsurface and the possibility of soil vibrations as a result of a geothermal heat project are also addressed.”

Collect facts

Under the Mining Act, the province has the task of advising the Ministry of Economic Affairs and Climate if an exploration and / or environmental permit is requested for a geothermal heat project. Of course you support that advice on the available facts wherever possible. That way you can also properly explain the advice and the developments that can take place in the region to residents. ”The search for available facts consists primarily of gathering the knowledge that is already available on the basis of published research reports, studies etc. In addition, ongoing studies and specific expertise from different parties (such as State Supervision of Mines and TNO) are also used.

Map with part of the groundwater protection zones in the province of Utrecht. Source: website province of Utrecht

Early in the process

The Province, Waternet and Vitens , eight municipalities, the Stichtse Rijnlanden Water Board, the Amstel, Gooi and Vecht Water Board and two environmental services have come together in the advisory process for the exploration permit for the Warmtebron Utrecht research projects . Youri: “In the advice on the license application geothermal energy. Together with these parties, we have asked the Ministry of Economic Affairs and Climate for extra attention to water quality. Groundwater is used for multiple purposes such as drinking water supply, agriculture and nature. By bringing different parties together at an early stage, you can discuss the options and risks with each other on the basis of facts and see which measures you can take to reduce the risks. In this way you create opportunities for a relatively new and promising technology such as geothermal heat. From the province of Utrecht we are looking at how we can properly support and facilitate the preliminary phase of research into geothermal heat. Geothermal heat offers an enormous opportunity to make a large part of our heat demand sustainable.possible risks . The main thing is that this geothermal heat must be extracted in a safe and responsible manner. ”

Uncharted terrain

“This is indeed a good example of how you can learn from and with each other and tackle matters in an area-specific way,” adds Eddy Yedema . At Waternet, he has been focusing for years as a policy advisor / environment manager on the theme of source protection for the benefit of drinking water supply. On behalf of the municipality of Amsterdam and the Amstel, Gooi and Vecht Water Board, Waternet is involved in drinking water supply, sewerage and water management. Eddy: “Geothermal heat is still relatively unexplored territory and is still in its infancy. We are also fully engaged in the energy transition within Waternet. What can we do in it ourselves? Given the impact that geothermal heat can have on our drinking water interests, we as a stakeholder for Warmtebron Utrecht are happy to think along with us about the possibilities and the impossibilities. ”

‘Determine together what functions are needed in the area and see how you can develop those functions in the subsurface as well as possible next to each other’

Valuable knowledge

Drinking water companies also see the potential of geothermal energy in the context of the energy transition. Eddy: “Although Waternet itself has no plans to do anything with geothermal heat, we recognize the importance of gaining as much valuable knowledge and experience as possible through research projects from Warmtebron Utrecht. What is possible and what is not? And Warmtebron Utrecht is explicitly looking for that. The starting point is how safe and responsible geothermal heat can be extracted near the built environment. Such research projects give us very important information and insight into how we as drinking water companies should deal with geothermal heat in the short and long term in relation to our drinking water sources. The point is that if things go wrong in the subsurface, then that is irreversible. You can’t do much about it then. ”

Precious and vulnerable

As a ‘precious and vulnerable public good’, the subsoil and everything that is naturally therein deserves optimum protection. For example, we know groundwater protection areas and drilling-free zones that lie around the water abstraction areas like a shell. “All our drinking water is made from groundwater. The subsurface is therefore crucial for the drinking water supply, “says Oeds-Willem Miedema from drinking water company Vitens. “Due to the increase in activities in the subsurface, functions will increasingly influence each other and we now have to make the right choices for the long term. And because the development of geothermal heat entails risks for the drinking water supply, it is important that we have discussions with each other about this at an early stage, ”says the strategic environment manager for the Utrecht, Flevoland and Noord-Holland regions. “The search area for the location for a test drill in Utrecht-Zuid / Nieuwegein is at some distance from two of our extraction sites. But since drilling is not allowed in or under a drinking water extraction area, the drinking water extraction sites are secured. That and early identification of current and future areas,

Develop side by side

According to the representatives of the drinking water companies, it is precisely the early involvement of such developments that is an important key to success. Eddy: “Just by looking at the front of a process together: ‘where is it possible and where is it not possible?’ Determine together what functions are needed in the area and see how you can develop those functions in the subsurface as well as possible next to each other. You cannot do everything everywhere. Sometimes you have to make choices. “Oeds-Willem:” If we bring together all the protection areas for drinking water in the Netherlands, it means more than 15 percent of the surface of the Netherlands. That is why it is important to place the figures in perspective, even though bottlenecks may occur locally. As a society we now have to make the right choices for the use of the subsurface. ”

Sharp on the content

Apart from the Utrecht research projects, the drinking water companies are looking with some care at the up-scaling that will have to take place in the near future. “We are now specifically talking about one test drilling. But if it is successful, it will of course not remain at this one place, “Oeds-Willem looks ahead. “That is why we need precisely this coordination to develop those functions in the subsurface without these getting in each other’s way.” According to him, learning is now mainly in the process and not yet in the content. “But from this positive experience, we come together more quickly to a supported process and choices. You do not always have to agree with each other and it is good that you, as interested parties, remain focused on the content. ”

More about groundwater protection zones in the province of Utrecht can be found on the website of the province of Utrecht. The digital map  with the zones can also be found there.

Source: WarmteBron