Nowadays, when the demand for energy is growing and fossil fuel resources are limited or their combustion has harmful effects on the environment, , the search for alternative sources is extremely important. One way is through ATES, which is the storage of thermal energy in the aquifer. This technology is gaining popularity around the world, as we wrote about in the 8/2023 (10) issue of Water Issues.
How does ATES technology work?
ATES (Aquifer Thermal Energy Storage) uses groundwater as a thermal energy storage medium. The system consists of at least one pair of boreholes, called doublers, which allow access to the selected aquifer. One of them acts as a source of cooling and the other as a source of heat.
During the summer season, low-temperature water is drawn from the cold hole and passed through the exchanger, where it removes heat from the air-conditioned building. It is then fed into the warm hole, where it is stored until the winter season, when the process reverses. The water is taken from the hot hole, then gives up heat in the exchanger and goes to the cold hole, where it waits for the next summer season.
Key parameters of ATES technology
The ATES system requires suitable geological conditions, such as the presence of an aquifer with a high filtration rate or limited hydraulic gradient.
Therefore, effective use of ATES requires a thorough understanding of the hydrodynamic and geological properties of aquifers. Hence, before implementing this technology in an area, a thorough geological study must be conducted to assess its potential and ensure its safety and effectiveness.
In Poland, due to the varying geological structure in different parts of the country, it is not possible to use this technology effectively everywhere.
ATES in Poland
In order to assess the potential for storing thermal energy in aquifers in Poland, the Polish Geological Institute-Public Research Institute(PIG-PIB) has been conducting since 2023. A project dedicated to this issue. It aims to make a comprehensive analysis of geological and hydrogeological conditions down to a depth of 200 meters below ground level, in order to evaluate the possibility of acquiring and storing low-temperature heat and cold in the range of about 5°C to 25°C.
The project is being carried out in cooperation with the Polish Academy of Sciences, the Institute of Mineral Raw Materials and Energy Management and the AGH University of Science and Technology in Krakow. The results of the research will be presented on the PIG-PIB website.
The analysis is based on archival materials and geological, hydrogeological and hydrochemical databases maintained by PIG-PIB. In the case of the possibility of applying ATES technology in Poland, the most promising areas for carrying out a pilot installation will be identified.
In addition, the project will assess existing regulations for the construction and operation of open systems in shallow geothermal energy, including thermal energy storage. The impact of energy storage systems in shallow aquifers and the potential risks, both to the environment and in case of possible conflicts with other infrastructure facilities, including existing and future groundwater wells, will also be analyzed.
Why develop ATES technology?
One of the key reasons why ATES technology should be developed is that it is green and has a low environmental impact. Unlike traditional energy storage methods such as batteries or hydroelectric power plants, ATES does not emit greenhouse gases or lead to changes in the landscape.
In addition, ATES technology can help improve the country’s energy security. By storing thermal energy in the aquifer, buildings can be heated or cooled more efficiently, reducing the need for grid energy. This, in turn, could lead to reduced dependence on fuel-supplying countries and the aforementioned improvement in the country’s energy security.
Implementation of the ATES system requires specialized knowledge and experience in hydrogeology and geological engineering. However, due to the growing demand for efficient and environmentally friendly energy sources, the development of this technology is an interesting and viable alternative to current solutions.