Aquifer thermal energy storage

An ATES system uses the aquifer to buffer seasonal reversals in heating and cooling demand.

ATES can contribute significantly to emission reductions, as buildings consume some 40% of global energy, mainly for heating and cooling.

[5] Mono-directional systems do not switch pumping direction, such that groundwater is always extracted at the natural aquifer temperature.

Closed systems store energy by circulating a fluid through a buried heat exchanger that usually consists of a horizontal or vertical pipeline.

Storage of thermal energy in aquifers was suggested in the 1970s which led to field experiments and feasibility studies in France, Switzerland, US and Japan.

However, excess groundwater flow may transport (part of) the stored energy outside of a well's capture zone during the storage phase.

[13] To reduce advective heat loss, aquifers with a low hydraulic gradient are preferred.

[14] Regulations for installations concern the use of hazardous materials and proper backfilling of the borehole to avoid hydraulic short circuiting between aquifers.

Among the common contaminants, chlorinated ethenes have the most chance to interfere with ATES systems, as they are often found at similar depths.

[18] Increased temperature around the warm well can enhance reductive dechlorination of chlorinated ethenes.

ATES can be used as biostimulation, for example to inject electron donor or microorganisms needed for reductive dechlorination.

The combination concept of ATES and enhanced natural attenuation (ATES-ENA) can possibly be used in the Netherlands and China, especially in urbanized areas.

Currently, the combination concept may be better applicable for the Netherlands which offers more mature technology and greater experience.

[18] A 2023 study reported that ATES could reduce the use of energy in heating and cooling US homes and businesses by 40 percent.