In Ireland the wind blows stronger at night thanks to the weather systems blowing off the Atlantic ocean from the Gulf stream — just when demand for wind power is lowest. It means much of this potentially cheap and abundant power is wasted.

• What’s needed to make the most of this power is something like a gigantic battery that will store energy and release it when needed.

• Gaelectric wants to use water to carve out storage caverns in the salt deposits beneath the ground in the Larne area. There are two salt layers — the Triassic and the deeper Permian — which are what remains of two Mediterranean type seas from millions of years ago.

• Wind energy is already being harnessed by Gaelectric in wind farms in Ireland, with 250 megawatts of wind power under development in Northern Ireland and 70 megawatts in the South.

• In Northern Ireland it has nine wind farm projects in planning in Crockbrack, Cappagh, Corby Knowe, Dunbeg, Inishative, Carn Hill, Cregganconroe, Cloonty and Smulgedon.

• Wind energy would be used to compress air and store it in the salt caverns at depths of up to 1km. It’s stored until day time when everyone gets up, puts on the kettle and demand rises sharply.

• At that point the compressed air is released into a turbine which generates electricity for the grid.

• Matching the technology up to the market is complicated and will requires the help of geologists, economists, power engineers and market specialists. Gaelectric has carried out advanced modelling to predict what the power market will be like in 2020 when renewable energy is expected to have achieved 40% market penetration.

• The annual £21bn global energy storage market is expected to grow by 55% to £33bn by 2012. Venture capital expenditure supporting energy storage projects increased by 74% to £360m in 2007 with bulk energy storage for energy utilities having most potential.

• The first step is to determine how extensive the salt deposits in the Larne area are, so Gaelectric has applied for a Mineral Prospecting Licence from the Department of Enterprise, Trade and Investment in Northern Ireland to undertake further investigative work.

• If it’s found to be feasible to use the salt for air storage, the facility would be constructed by leaching caverns, compression and withdrawal testing of air from the caverns, combined with installation of the CAES machinery and infrastructure, possibly requiring a capital investment of up to £200 m.

• The approximate timescale for development and construction of a plant is at this stage expected to be between three and five years. If successful Gaelectric would anticipate securing an exploration licence by late 2011 and aim to have plant operational by 2015/16.