March 2025
Storing heat in the subsurface can be done in several ways. High Temperature Aquifer Thermal Energy Storage (HT-ATES) is one of them. With this technology, heat can be stored as well as produced. Storage is usually done in summer with injection of hot water into underground wells. That heat can later be utilised during colder periods.
The potential of the subsurface for HTO-ATES is influenced by other factors than those for deep geothermal. Important factors are the presence of a sealing clay layer and heat recovery efficiency. In addition, HT-ATES is different from geothermal energy because the system is alternating between injecting hot water in summer and producing heat in winter. Therefore, wells are used for both injection and production, which is not the case with geothermal doublets. In some cases, even more than two wells can be used in a plant. The economic model for HT-ATES also differs from geothermal energy due to the use of different drilling techniques and materials.
HT-ATES potential maps
A ‘ThermoGIS-HT-ATES’ application has been developed in WarmingUP theme 5 to map the potential of HT-ATES in the Netherlands. The current ThermoGIS application for geothermal energy was used as a basis for the calculations, by extending it with three models:
- a subsurface thermal flow simulator (ROSIM-DoubletCalc3D);
- an technical model for HT-ATES systems;
- a generic cost model.
Update calculation tool
The calculations done in ThermoGIS-ATES, such as flow rate ((volume flow rate of water in m³/h), are still under development and therefore not yet available at www.ThermoGIS.nl. There are not yet enough examples of operational ATES projects that can be used for verification and calibration of the models. The calculation tool is regularly updated based on new insights.
Improving calculation methods
In WarmingUP GOO, TNO, together with research partners, industry, governments and other interested parties, is investigating the improvement of calculation methods. We are also assessing the extent to which rules of thumb for maximum achievable flow rate and new geological input (from local or regional studies, for example) can contribute to improving the maps. The aim is to better unlock the subsurface potential for HT-ATES. This will also enable better, initial screening for HT-ATES projects.
Input is most welcome in this regard. You are therefore invited to contact TNO if you have any interest or ideas.
Input for calculations
(Hydro-)geological maps of the depth, thickness and permeability of aquifers (water-bearing layers in the subsurface) are used to calculate HTO-ATES potential. For HT-ATES is typically looked at a depth between 100-500 meters, shallower than the current ThermoGIS aquifers. Formations that are also interesting for HT-ATES, such as the Maassluis and Oosterhout Formation, are currently not available in ThermoGIS because the aquifers have not (yet) been mapped using the ThermoGIS workflow. Therefore, in the ThermoGIS-HT-ATES Mapviewer, currenlty only the Brussels Sand Member (NLDOBR) is visible.
Nevertheless, to provide insight into the HT-ATES potential of the Maassluis and Oosterhout Formation, potential maps have been created with input from the Regional Geohydrological Model REGIS II v2.2. These maps, based on interpolation between (shallow) borings, are less certain in places where few borings are available.
Work in ThermoGIS and WarmingUP GOO will include improving the moderately deep (~100-500m) regional hydrogeological models. These will eventually also be used for ThermoGIS-HT-ATES.
HT-ATES potential Maassluis and Oosterhout Formation
The storymap below shows potential maps for four relevant sand layers in the Maassluis and Oosterhout Formation in the mid-deep range (100-500 m). As these formations are considered favourable for HT-ATES, they have been run through with the ThermoGIS-HT-ATES app.
Because the input maps were created differently than the maps in the ThermoGIS Mapviewer, they are shown separately and provided with explanations.
Future developments
Together with research partners, industry, governments and other interested parties, we are working on:
- mapping of moderately deep regional hydrogeological models;
- the addition of aquifers in ThermoGIS-HT-ATES;
- improving computational methods for HT-ATES;
- including uncertainty (P-values) in the potential maps;
- integrating a heat pump model to ThermoGIS-HT-ATES workflow;
- an interactive app where users can provide input for the creation of the potential maps.
Input is most welcome. You are therefore invited to contact TNO if you have any interest or ideas.
Relevant documentation and background information
The report explaining the ThermoGIS-HTO application and the example maps can be downloaded here: Vrijlandt at al. (2023). ThermoGIS-HTO: National High Temperature Aquifer Thermal Energy Storage potential tool.
The WINDOW phase 1 (predecessor of the WarmingUP project) report, with qualitative approach to HTO potential: Dinkelman et al. (2020). B2 potentieel en toepassingscondities. Geologisch model, temperatuurmodel voor de ondiepe ondergrond en potentieelkaarten voor HTO in Nederland.
Project: WarmingUP (theme 5) + PIO Aardwarmte
This project was carried out as part of the Innovation Plan WarmingUP. It was enabled in part by a grant from the Rijksdienst voor Ondernemend Nederland (RVO) under the subsidy scheme Multi-Year Mission-Driven Innovation Programmes (MMIP RVO project number TEUE819001). WarmingUP fulfils MMIP-4 Sustainable heating and cooling in the built environment, thus contributing to Mission B - A CO2-free built environment in 2050.
Pio
Contactperson
Do you have suggestions or questions about the ThermoGIS-HTO application or this page? If so, please contact Dorien Dinkelman. For other ThermoGIS questions, please get in touch via the contact form on this website.