Research by Lawrence Berkeley National Laboratory and Princeton University’s Andlinger Center for Energy and Environment suggests that using groundwater to maintain comfortable temperatures in buildings could reduce natural gas and electricity consumption in the US building heating and cooling sector by 40%.
The method called Aquifer Thermal Energy Storage (ATES, or Aquifer Thermal Energy Storage) is based on the concept of retaining energy underground in the form of temperature. ATES can heat and cool buildings while preventing failures due to high energy demand during extreme weather conditions.
The study showed that ATES could fit into the broader goal of decarbonizing US energy systems through renewable energy storage. It would be used in the absence of sufficient sunshine or wind for energy production. The researchers said ATES is a favorable option that, along with other technologies such as batteries, could help eliminate dependence on fossil fuels and enable a full transition to renewable energy.
How does it work?
The ATES method involves storing heat or cold in aquifers. Thermal energy is recovered when water is exploited through wells. In summer, extracted from cold wells, it cools buildings. After receiving heat and reheating, it returns to the warm wells. In winter, the direction is reversed – hot water is transferred to the buildings, and after giving up the stored energy, it returns to the cold ones.
ATES systems are designed to avoid impacts on drinking groundwater supplies and do not introduce any pollutants into the water environment.
ATES is not yet widely used in the U.S., but is gaining recognition around the world. One of its main advantages is that the system obtains free thermal energy from seasonal temperature changes, which can be enhanced by adding heating and cooling generated by electricity.
ATES in numbers
In a study published in Applied Energy, researchers created a power grid model for a Chicago neighborhood using various energy storage options, including groundwater. It turned out that the use of ATES could reduce fossil fuel consumption by 40%, although the cost of its implementation would be 15 – 20% higher than with traditional technologies.
However, the researchers believe that after a few years of using ATES systems, the depreciation costs will have paid off and the solution will be more cost-effective.
Another advantage of ATES is also the efficiency gains associated with anticipated climate change. Hotter summers and harsher winters can increase the amount of free thermal energy stored underground.
Studies show that the use of ATES is an attractive form of heating and cooling energy storage that can help make us independent of fossil fuels and enable the creation of a fully green energy grid.