Accelerate Energy Transition with Aquathermia 2.0

In its National Climate Agreement, the Dutch government has made commitments to reducing the emission of CO2. One of the sectors referred to in the agreement is the built environment. Heat demand represents the biggest challenge in making homes more sustainable; for an existing home, the demand for heat is by far the largest component of total energy demand. Aquathermia (‘heat and cold from water’) is one of the alternatives for the sustainable heating and cooling of existing districts. One of the forms of aquathermia is TED: Thermal Energy from Drinking Water.

What is aquathermia?

Aquathermia is the collective name for thermal energy that can be extracted or recovered from water sources in the vicinity, for the provision of heat and/or cold. A distinction is made between thermal energy from surface water (TEO in its Dutch acronym), from wastewater (TEA in its Dutch acronym) and from drinking water (TED). Each category can be further subdivided into different types depending on the sources. For example, a distinction can be made within TED between raw water and purified water. In contrast with most other sustainable energy sources, aquathermia can actively reduce summer heat stress by extracting heat from water in the summer and, combined with seasonal subsurface storage (ATES), enable its use to replace fossil energy sources in the winter.

Aquathermia is a ‘low temperature (LT) heat source’. This means that it still requires a heat pump to bring the heat level to a temperature suitable for heating. The temperature required depends on the degree of insulation (energy label) of the object to be heated. All RESs (Regional Energy Strategies) consider aquathermia as a sustainable LT heat source. More than half of the RESs also refer specifically to Thermal Energy from Drinking Water (TED) as an option. The energy transition thus presents the drinking water sector with a question: To what extent can the current drinking water infrastructure be used to contribute to the heating transition?

The TED concept and its connection with an ATES installation (in this case, for the supply of cold from a raw water pipeline). Source: Dunea website.

Knowledge development needed for scaling up of TED

Aquathermia and TED is not new technology. TED has been in use in the Netherlands for about 15 years, including for the provision of collective heating, as in the example of the EVA-Lanxmeer district in Culemborg. A key question in this context concerns how far it is possible to scale up TED in combination with the primary mission of the drinking water utilities, namely, the provision of drinking water of impeccable quality.

The EVA-2 project in WiCE will build further upon the knowledge of aquathermia/TED developed in the WarmingUP programme, on the basis of the following project lines:

  1. Standardisation, both regarding technical implementation as well as procedures, such as contract formation (WP 2 and WP 4 in the project plan).
  2. Quantitative view of the effects of TED, both regarding the temperature in the distribution network and the water quality (WP 1 and WP 3 in the project plan).
  3. Knowledge sharing and learning from experience. This also includes maintaining the national Aquathermieviewer as far as its TED component is concerned (WP 5 and WP 6 in the project plan).

Staff members from the drinking water utilities can find the project plan on Sharepointpagina van BTO/WiCE.

Points 1 and 2 concern two different subprojects. Subproject 2 involves the use of a test installation which was developed within WarmingUP (further information available behind the link, see also photo below). This test installation is being used to run tests at two drinking water utilities in the Netherlands and Flanders.

Test installation for quantitative continuous research into the effects of aquathermia on the drinking water quality. Source: KWR.

Collaboration and knowledge sharing

In the above project lines the drinking water utilities and KWR collaborate with various partners, such as the Association of Water Authorities, Rijkswaterstaat, consultancies, other knowledge institutes and the Netwerk Aquathermie – which per 1-1-2024 moves to the Stichting Warmtenet foundation –, the Energy and Resources Factory (EFGF), and the Nationaal Programma Lokale Warmtetransitie (NPLW) (National Programme Local Heating Transition). The WiCE Energy Network Group is active in knowledge sharing within the drinking water sector. This group also serves as a sounding-board committee for the EVA-2 project. Knowledge generated during the course of the project is made available through reports and webinars, which are accessible to drinking water utility staff.