Donegal is set to host Europe’s first large-scale 10MW iron-air battery, capable of storing one gigawatt hour (GWh) of energy.

Once operational, the battery will be able to discharge energy at its full power output for up to 100 hours when fully charged.

The ESB and Coillte's joint venture FutureEnergy Ireland has submitted a planning application to Donegal County Council to build the battery near Buncrana.

Iron air

This new form of multi-day storage is made from low-cost iron, water and air. The principle of operation is reversible rusting - while the battery is discharging, it absorbs oxygen from the air and converts iron metal to rust - while charging, the application of an electrical current converts the rust back to iron, releasing oxygen.

This 10MW project will be capable of storing more than half the energy capacity of Turlough Hill, while future projects in development will be capable of storing up to 8GWh.

Congestion

The battery will be able to absorb a high volume of surplus Irish renewable energy during times of high output and provide renewable power back into the Irish grid system when it is needed.

It will also relieve grid congestion issues faced by wind and solar projects, reducing the need for new overhead power lines.

Donegal has one of the most congested electricity grids in Ireland and is particularly challenging for securing planning permission for renewable projects. A decision is due in November.