North Sea Seabed Holds Energy Storage Potential – Study

Rocks in the seabed off the UK coast could provide long-term storage locations for renewable energy production, according to the new research by the Universities of Edinburgh and Strathclyde.

Engineers and geoscientists from the Universities of Edinburgh and Strathclyde used mathematical models to assess the potential of the process, called compressed air energy storage (CAES).

The team then predicted the UK’s storage capacity by combining these estimates with a database of geological formations in the North Sea.

Using the technique on a large scale could store enough compressed air to meet the UK’s electricity needs during winter, when demand is highest, the study found. Porous rocks beneath UK waters could store about one and a half times the UK’s typical electricity demand for January and February, the study found.

Compressed air energy storage would work by using electricity from renewables to power a motor that generates compressed air. This air would be stored at high pressure in the pores found in sandstone, using a deep well drilled into the rock.

During times of energy shortage, the pressurised air would be released from the well, powering a turbine to generate electricity that is fed into the grid.

A similar process storing air in deep salt caverns has been used at sites in Germany and the US.

Locating wells close to sources of renewable energy – such as offshore wind turbines – would make the process more efficient, cheaper and reduce the amount of undersea cables required, the team says.

”This method could make it possible to store renewable energy produced in the summer for those chilly winter nights. It can provide a viable, though expensive, option to ensure the UK’s renewable electricity supply is resilient between seasons. More research could help to refine the process and bring costs down,” Dr Julien Mouli-Castillo,
School of GeoSciences, said.

The study was funded by the Engineering and Physical Science Research Council, Scottish Funding Council, and the Energy Technology Partnership.

Photo: Ørsted

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