Characterizing the subsurface for HT-ATES well design and thermal impact analysis: a case study

“In this study, well requirements to design the subsurface part of a High Temperature Aquifer Thermal Energy Storage (HTATES) are described and assessed for a case-study in Delft (NL). Two recent drillings in Delft are used to design the HTATES well. Three main design requirements are identified: flow rate per well, recovery efficiency of the well(s) and the thermal impact to the subsurface. The results of this study show that two layers in Delft between -45 and -184m depth have potential as a storage aquifer for HT-ATES. Because of the higher well flow rate and anticipated smaller thermal impact the deeper storage aquifer is chosen. Based on the flow rate assessment a single doublet should be sufficient to meet the required capacity. Numerical simulations show that the recovery efficiency is 74% after 5 years. The heat losses occur mostly strongly (>50%) towards the top sealing layer, and after five years the thermal energy lost to the shallower layers is greater than the yearly stored thermal energy in the aquifer. The temperature effect, described by monitoring the distance of the +5, +15 and +40 °C temperature increase contours, is two times faster upwards (to shallower layers) compared to deeper layers downwards.”

(Citation: Beernink, S.T.W., Bloemendal, J.M., Hartog, N., Vardon, P.J. – Characterizing the subsurface for HT-ATES well design and thermal impact analysis: a case study – European Geothermal Congress, Zurich, Switzerland, 6-10 October 2025)