Japanese technology firm Mitsubishi and Scottish energy supplier SSE are going to test the limits of energy storage with what is effectively a gigantic rechargeable battery in the Orkney Islands.

The battery will mostly store extra renewable energy generated by the community wind farms on the islands. The trial is meant to show a stable power supply is possible in the area, which has a high proportion of renewable energy compared with demand.

Made up of two huge 40ft long cargo containers which each hold 2,000 lithium-ion rechargeable batteries, the energy storage system will have a maximum power output capacity of 2MW (megawatts).

Another big container will house a system to convert direct current (DC) and alternating current (A/C) plus all the input and output controls.

The energy storage system will be installed at Kirkwall Power Station, one of SSE’s back up power generators. When there is a slight power shortage or power surplus, energy will be transmitted from or to the mainland through a submarine cable.