Shallow Aquifers for ThermoGIS-HTO
October 2026
Heat can be stored underground using High-Temperature Thermal Energy Storage (HTO). To assess the potential of HTO in the Netherlands, ThermoGIS is being expanded with dedicated calculation methods for heat storage in water-bearing geological formations (aquifers).
Adding shallow aquifers
We are currently working on adding shallow aquifers to ThermoGIS, including the Oosterhout Formation and the Maassluis Formation. These datasets are still under development and may change as new data and insights become available. The ultimate goal is to perform HTO potential assessments for these aquifers, enabling a better evaluation of their suitability for large-scale underground heat storage.
First Maassluis and Oosterhout Formation maps based on REGIS
To provide an initial indication of the HTO potential of the Maassluis and Oosterhout Formations, we have developed preliminary potential maps using data from the regional hydrogeological model REGIS II v2.2. These maps are based on information from shallow boreholes and are therefore more uncertain in areas where borehole data are sparse, particularly for parts of the Maassluis and Oosterhout Formations.
As these maps are based on a different methodology and data source than the standard ThermoGIS layers, they are not included in the ThermoGIS Map Viewer. Instead, they are presented separately in the Storymap below.
Qualitative overview map
In addition, we are developing a qualitative HTO overview map that includes all relevant shallow aquifers from REGIS. This map will provide a first indication of the potential suitability of shallow aquifers for heat storage across the Netherlands. As a next step, these aquifers may be evaluated quantitatively using dedicated HTO calculations.
We are also working on adding point data from existing and planned HTO projects, giving users more insight into real-world applications and ongoing developments in underground heat storage.
For the best user experience, view the ArcGIS StoryMap on a standard laptop or desktop screen (13–17 inch).
The text continues below the StoryMap.
Future developments – contribute your ideas!
Together with research partners, industry stakeholders, government bodies, and other interested parties, we are continuing to develop ThermoGIS-HTO. Current activities include:
- Improving regional hydrogeological models for intermediate depths (approximately 100–500 m).
- Adding additional aquifers to ThermoGIS-HTO.
- Enhancing HTO calculation methods, including improved screening criteria and estimates of maximum achievable flow rates.
- Incorporating uncertainty estimates (P-values) into HTO potential maps.
- Integrating a heat pump model into the ThermoGIS-HTO workflow.
- Developing an interactive application that allows users to contribute data and insights for improving HTO potential assessments.
We welcome feedback, ideas, and collaboration opportunities. Please feel free to contact TNO if you would like to contribute or discuss future developments.
Relevant documentation and background information
The report describing the ThermoGIS-HTO application and example maps can be downloaded here: Vrijlandt et al. (2021) ThermoGIS-HTO: National High Temperature Aquifer Thermal Energy Storage potential tool.
The WINDOW Phase 1 report (a precursor to the WarmingUP project), which presents a qualitative assessment of HTO potential in the Netherlands, can be found here: Dinkelman et al. (2020). B2 potentieel en toepassingscondities. Geologisch model, temperatuurmodel voor de ondiepe ondergrond en potentieelkaarten voor HTO in Nederland.
Credit
M. Vrijlandt, H. Veldkamp, J. Mos, M. Koenen, H. Brett, M. Andova, E. De Boever, D. Dinkelman, the WarmingUP (GOO) project team, and PIO Geothermal Energy.
This work was carried out within the framework of the WarmingUP Innovation Programme and PIO Geothermal Energy.
WarmingUP was partly funded by the Netherlands Enterprise Agency (RVO) through the Multi-Annual Mission-Driven Innovation Programmes (MMIP) scheme (RVO project number TEUE819001). WarmingUP contributes to MMIP-4 Sustainable Heating and Cooling in the Built Environment and supports Mission B: A COâ‚‚-free Built Environment by 2050.
PIO Geothermal Energy (Research and subsurface information provision through ThermoGIS.nl for the national potential of geothermal energy and underground heat storage) is part of the TNO-GDN task-funded programme for the Dutch government.
Contact
Do you have suggestions or questions about the ThermoGIS-HTO application or this webpage? Please contact us through the contact form on this website.