The technologies
The PUSH-IT project will, for the first time, demonstrate three types of high temperature geothermal heat storage: Aquifer Thermal Energy Storage (ATES), Borehole Thermal Energy Storage (BTES) and Mine Thermal Energy Storage (MTES). Each type of technology is explained below.
What is Aquifer Thermal Energy Storage?
Aquifer Thermal Energy Storage (ATES) is the storage and recovery of heat in aquifers, which are permeable layers that contain groundwater. ATES systems use two or more groundwater wells: hot wells and warm/cold wells.
During summer, water is extracted from the warm/cold well and heated, for example using geothermal energy. Then, the hot water is injected into the hot well, where it is stored.
During winter, heat is extracted from the hot well, and can be used to heat buildings in a district heating grid. When the heat is used, the water is pumped back into the warm/cold well.
ATES technology year round
Systems commonly operate at low temperature level in combination with a heat pump. Heat storage at higher temperature levels in ATES has large potential but requires development of the technology before large scale adoption is possible. Currently, there are less than ten high-temperature ATES systems operational world-wide, compared to more than 3000 low-temperature ATES systems.
In PUSH-IT, high-temperature ATES is developed at the pilot sites in Delft (Netherlands) and Berlin (Germany).
What is Borehole Thermal Energy Storage?
Borehole Thermal Energy Storage (BTES) is a large, underground heat exchanger. A BTES system consists of a set of tubes installed in the underground, placed vertically in a borehole. Water circulates in the tubes, which allow for heat exchange with the surrounding sediment or rocks. In summer warm water circulates, causing the underground around the borehole to heat up. In winter cold water is circulated to extract the heat from the underground.
BTES technology year round
BTES systems generally have lower capacity than ATES systems. Like ATES, BTES is commonly applied at low temperature levels in combination with a heat pump but requires development to be used for higher storage temperature. Currently, more than one million low-temperature BTES systems are operational worldwide. PUSH-IT is developing high-temperature BTES systems.
In PUSH-IT, high-temperature BTES is developed at the pilot sites in Darmstadt (Germany) and Litomĕřice (Czechia).
What is Mine Thermal Energy Storage?
Mine Thermal Energy Storage (MTES) uses the mine water present in abandoned mines. The mine water is used as a carrier for transporting the heat to and from the mine. So, like ATES, hot water is injected into the mine during summer, and extracted in winter.
MTES technology year round
MTES is a technology under development: currently less than five systems are operational worldwide.
In PUSH-IT, high-temperature MTES is developed at the pilot sites in Bochum (Germany) and United Downs (United Kingdom).
PUSH-IT is a project funded by the European Union’s Horizon Europe research and innovation programme under grant agreement No 101096566.
Funded by the European Union. Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union. Neither the European Union nor the granting authority can be held responsible for them.
