Year Review 2021

WarmingUPdate: where are we now, where we are headed?

Challenges, objectives and themes of the Innovative Sustainable Heat Collective 2020-2022

We are halfway through the WarmingUP period and well on our way. So it’s time for a detailed update. In January 2020, the extensive research programme funded by RVO from the Multi-Year Mission-Driven Innovation Programmes (MMIP) began with 40 participants and partners. The goals are ambitious. Collective heating systems – the core of WarmingUP – are an extremely promising option for the energy transition in the Netherlands. KWR researchers are formulating the challenges, objectives and themes of this Innovative Sustainable Heat Collective, which is located at the interface between water and energy.

The approach of WarmingUP is in line with the MMIP objectives; a new approach from government to encourage innovations deriving from the Climate Agreement. One of the aims is to introduce sustainable heating and cooling to the built environment. WarmingUP focuses on collective heating systems and the associated knowledge development. The consortium consists of TNO (lead partner), Deltares, KWR, universities, provincial and municipal authorities, heating companies, network operators, contractors and consultancies. The drinking water companies and KWR are working in the WarmingUP project ‘Aquathermal energy’ (part of the Water in the Circular Economy programme – WiCE) on the development of energy from drinking water.

Energy transition

‘The mission of the government and the heating sector is to scale up the construction of collective heating systems,’ explains KWR researcher Marette Zwamborn. She is one of the WarmingUP theme coordinators. ‘We have to make progress from the 340,000 homes connected to a heat network in 2018 to 1.1 million homes by 2030. The heating systems also have to be sustainable. Geothermal, aquathermal and heat storage technologies are being investigated. The aim is to achieve a carbon reduction of 70 percent by 2030 compared with the average household central heating boiler of 2018. And finally, the design, construction and management of the heating facilities must, of course, be cost-efficient. To keep the energy transition affordable, the aim is an annual efficiency gain of 1.5%. That is a big ask for the required system and process innovations.’

Six research themes

In WarmingUP, the shared goals formulated by the consortium have been split up into six research themes. First of all, innovation and cost reductions with heat networks. Two themes address this: the design of smart heat networks (Theme 1) and their large-scale and cost-effective construction (Theme 2).

The next two goals of WarmingUP dovetail perfectly with KWR’s wish to use water knowledge for the energy transition. That is why KWR is contributing to the themes that have been formulated for this purpose. Zwamborn: ‘It’s about unlocking the technical potential of sustainable heat, including reducing costs and risks, and optimising the techniques. We are looking at sustainable sources: aquathermal (theme 3) and geothermal energy (theme 4). And because there is also a difference between supply and demand, we are also looking at underground high-temperature heat storage (theme 5). KWR is the lead partner for this last theme.’

WarmingUP is also focusing on the public’s perspective and the action perspective of government and market players, explains Zwamborn. That is bound up with the need for meticulous implementation to go hand in hand with support for the initiative. ‘Theme 6 explores the integration of collective heating systems in society as a whole. Perhaps the most important challenge in the entire heat transition.’


Andreas Moerman (KWR) provides a clear explanation of aquathermal energy (theme 3). He is the project manager for this theme in WarmingUP. ‘With aquathermal energy, we are talking about extracting heat from the environment, in this case from surface water (TEO), waste water (TEA) or drinking water (TED). KWR is focusing on the third area. Some people are wondering whether this can make a meaningful contribution. But there really are practical examples in place already. They demonstrate that TED works and that it can make a substantial contribution to the local heat transition.’

‘We have three projects where we are implementing the theme of aquathermal energy. Firstly, with data from Brabant Water, Dunea, PWN, Vitens, Waterbedrijf Groningen, Waternet and WML, we have visualised the potential for TED. One look at the aquathermal viewer makes it clear where there is a reasonable chance that drinking water can serve as a useful source for thermal energy.’

‘The second aquathermal project involves studying the effects, for example on the microbiological quality of drinking water. This is a wide-ranging area, which is why there are three sub-projects. In this project, KWR is investigating the quantitative impact of TED on drinking water quality depending on temperature and material use. We are optimising the way the drinking water temperature can be modelled as input for business cases and impact studies. And we are providing a picture of the possible impact of large-scale aquifer thermal energy on the distribution of contaminants in the soil.’

Finally, Moerman explains the third aquathermal project, which involves establishing a clear picture of the possible technologies. ‘The first report has been completed. It provides a clear overview of aquathermal systems and the associated costs. A subsequent report is in the pipeline. It describes current knowledge relating to the design and management of the systems. It is extremely useful to be able to access this information in one place.’


KWR plays a modest role in the geothermal energy theme. ‘TNO is the the partner here,’ says Zwamborn. ‘KWR is studying the environmental effects of geothermal energy, for example by modelling the distribution of brine in the groundwater layer in the event of a leak.’

Underground heat storage (high temperature storage)

KWR is playing an important role in WarmingUP in theme 5, which targets the development of high temperature storage (HTO): the underground storage of surplus heat in the summer for later use in the winter. Zwamborn describes the four projects covered by this theme. ‘In an overall learning by doing project, we are integrating all the knowledge we have developed about underground heat storage. In the first step, we conducted exploratory studies for seven locations. That identified the three most promising locations. We will develop them further in pilot projects, taking a broad view of the business case, legal feasibility, geohydrological feasibility, stakeholder commitment and planning. Because we were able to compare locations, we were also in a position to learn more about the expected costs of HTO technology. It emerged that the storage volume is a strong determinant here.’

‘Potential maps were then developed to show the areas in the Netherlands that are most suitable for HTO. TNO supplied and processed the required knowledge and geohydrological feasibility was assessed in the same way as in the seven exploratory studies I just mentioned.’

KWR’s knowledge is particularly evident in the project looking at the design, efficiency and effects of HTO. The emphasis here is on using information from the drinking water sector, soil energy, geothermal energy, oil and gas. Such as knowledge about design standards for wells and how to prevent lime deposits at high temperatures. As well as knowledge about the temperature effects in the subsurface and geochemical effects. ‘A total package that is right for KWR, where we have years of experience with drinking water extraction and groundwater quality,’ says Zwamborn.

WarmingUP is also looking at the governance aspects of HTO. For example, the final project in this theme is working on the assessment frameworks for licences and the drafting of a legal background document. Zwamborn: ‘At the moment, provinces still have no concrete guidelines for issuing licences. By jointly elaborating the assessment factors that need to be considered, licensing authorities can establish a sounder basis for the legal framework for HTO.’

The integration of heat networks in society

Finally, one theme looks at how collective heating systems – and the heat transition in general – can be integrated in society and how we can meet the social and institutional preconditions for these developments (theme 6). As a governance researcher at KWR, Nicolien van Aalderen explains the three WarmingUP projects that address this theme.

‘KWR is taking the lead in the project on the acceptance of heat networks by local residents. It is important for municipal authorities, housing corporations and heating companies to have a picture of what is important for acceptance and to provide them with possible approaches to enhance that acceptance. We distinguished between acceptance by whom and of what. Looking at the general public, local residents and clients separately, including the type of acceptance associated with them, makes everything a lot clearer. The action perspectives developed will result in pilot projects. In this way, the parties involved can see how to get local residents on board.’

Two other projects covered by the social theme address governance issues, Van Aalderen continues. ‘These studies involve the joint development and testing of innovative collaborative and financing models by the various parties involved in the heat chain, from production and distribution to use. And selection tools are being developed for municipal authorities so that, when they make the switch to a collective heating system, they can also look at upscaling options and opportunities to link up with the construction of other infrastructure.’

WarmingUP result

It is obvious that WarmingUP should result in more sustainable, reliable and affordable collective heating systems. WarmingUP will come to an end in late 2022. So what is the most important result? ‘WarmingUP provides knowledge and insights that the heating sector and governments can actually use,’ says Zwamborn. ‘And a community has now been created in which the parties involved can find and understand each other faster. Ultimately, the idea is that this will lead to the acceleration of the construction of collective heat networks with sustainable sources in a cost-effective way and with adequate support.’