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 for the simultaneous injection and extraction of groundwater to carry heat to or from the aquifer. Storage and recovery of heat is achieved by injection of hot groundwater in the so-called hot well in summer and extraction from the warm or cold well in winter. Hence, the groundwater is used as a carrier for the heat.
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.
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 systems generally have lower capacity then 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.
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.
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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.
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