The economic expansion of renewable energy systems requires long duration energy storage capacity. These systems can harness intermittent sources such as solar and wind, and produce sustainable energy for weeks and even months, surpassing the capabilities of lithium-ion batteries. A novel approach to achieving this goal is about to be field-tested by Israeli company BaroMar.

An underwater large-scale, long-duration energy storage pilot project is planned off the coast of Cyprus. The approach entails the installation of underwater enclosures near coastlines with access to deep water and relying on the pressure of the water column to store compressed air. The tanks are constructed on shore, using marine-proven concrete and steel, then towed into place.

New long duration, large scale compressed air energy storage system leverages water pressure to cut costs. Source: BaroMar

Excess electricity from wind and solar resources will be transmitted by subsea cable to the tanks, where it feeds compressors. When more electricity is needed, the compressed air is fed back to land where it is expanded and fed into a generator.

By leveraging mature power technology with the hydrostatic pressure of the seawater, the 4 MWh pilot system aims to achieve relatively low installation costs and the lowest levelized cost of storage. The developers also expect to achieve a round-trip efficiency goal of up to 70%.