High temperature aquifer thermal energy storage performance in Middenmeer, the Netherlands: thermal monitoring and model calibration

In 2021, the first full scale high-temperature aquifer thermal energy storage (HT-ATES) system became
operational in Middenmeer, the Netherlands. The system is operated by ECW Energy and realized within
the framework of the GEOTHERMICA HEATSTORE project. A dedicated monitoring program, including
distributed heating sensors (distributed temperature
sensing, DTS) at the hot well, cold well and monitoring
well was deployed to keep track of the field
performance.
In this study, a first attempt at monitoring data
evaluation and model calibration is done based on data
from the first loading phase (heat injection), the resting
phase, and the unloading (heat production) phase at the
HT-ATES site in Middenmeer. Although a technical
flaw in the cable resulted in frequent noise signals, an
improved output could be generated using a filtering
technique. The DTS measurements in the monitoring
well in Middenmeer were able to capture the relevant
processes such as the passing of the thermal front
during injection and production, the upward flow of hot
water due to buoyancy and permeability variations, and
the heating of over- and underlying clay layers. A
baseline model and three uncertainty scenarios have
been analysed, and the first results show a good fit
between the monitoring data and the thermal model
scenario with a coarsening upward sequence in the
aquifer. The DTS data and reservoir parameters will be
investigated in more detail in a follow-up history
matching project. History matching might be a crucial
step in the initial operational phase in order to improve
future performance prediction and adapt, where
necessary, the operational control