ates

ATES, short for Aquifer Thermal Energy Storage, is a technology for storing thermal energy in natural groundwater aquifers for later use in heating and cooling buildings and processes. The system uses wells and heat exchangers interconnected with a building’s energy system or a district heating and cooling network. In seasonal ATES schemes, heat or cold is stored in the aquifer during times of low demand or high renewable generation and retrieved during periods of higher demand.

In operation, groundwater is circulated between the aquifer and a heat exchange loop. Depending on the season and configuration, the system can store summer heat to be used for winter heating, or store winter cold to be used for summer cooling; some installations support both storage directions within the same aquifer. The aquifer acts as a relatively stable thermal reservoir, helping to decouple energy supply from building loads and to increase the use of renewable energy and waste heat.

ATES is deployed in district heating and cooling schemes and in multi-building campuses, where it can reduce energy costs, fossil fuel use, and peak electricity demand. Its effectiveness depends on aquifer properties (permeability, porosity, thickness), aquifer temperature, well field design, and groundwater chemistry. Environmental and regulatory considerations include protecting groundwater quality, managing thermal plumes, and ensuring long-term monitoring of aquifer response. With proper design and operation, ATES can offer robust, low-carbon energy storage for built environments.