Underground cold energy storage technology

What is underground thermal energy storage?

Underground Thermal Energy Storage (UTES) A thermal energy storage is a system that can store thermal energy by cooling, heating, melting, solidifying or vaporizing a material , such as hot-water, molten-salt or a phase-change material. Sensible heat storage (SHS) relies on the temperature variation of a solid or liquid (e.g. water).

Why is the underground a good place to store thermal energy?

The underground is suitable for thermal energy storage because it has high thermal inertia, i.e. if undisturbed below 10-15 m depth, the ground temperature is weakly affected by local above ground climate variations and maintains a stable temperature [76, 77, 78].

What is Utes (underground thermal energy storage)?

There are also combinations in which the storage is used for both short-term and seasonal storage. There are a number of such technologies summarized by the acronym UTES (Underground Thermal Energy Storage). 30 years within the framework of IEA (International Energy Agency).

What are the different types of underground energy storage technologies?

For these different types of underground energy storage technologies there are several suitable geological reservoirs, namely: depleted hydrocarbon reservoirs, porous aquifers, salt formations, engineered rock caverns in host rocks and abandoned mines.

Are solar energy storage systems underground?

The experience of USTES applications worldwide in recent years shows that most of the solar energy seasonal storage projects have significant economic, social and environmental benefits. However, the key part of solar energy storage system is underground.

Do Underground Technologies still have room for future improvements?

The described underground technologies still have plenty of room for future improvements, especially in what relates to efficiency and new developments of technologies, their costs and economics aspects. Criteria for selecting underground reservoirs are very important for the success of an energy storage facility.