Belfast Telegraph

Thursday 24 July 2014

Salt caverns in Antrim coast to store wind power

The salt mines on the Co Antrim coast which are used for road salting operations across the province every winter. The salt deposits in the same area could be used to store wind power. Picture courtesy of BBC
The salt mines on the Co Antrim coast which are used for road salting operations across the province every winter. The salt deposits in the same area could be used to store wind power. Picture courtesy of BBC

Up to £200m is to be pumped into an ambitious scheme that will see wind power injected into salt caverns deep beneath the Antrim coast.

The unique geology of the Larne area will allow energy generated by wind farms to be stored underground and released at times of peak demand as part of a world-leading project announced this morning, according to renewables company Gaelectric.

It promised that up to £200m will be invested in the plant over three years, providing an estimated 200 jobs across the construction and engineering services sectors.

Until now, critics of wind power — including Environment Minister Sammy Wilson — have warned that it is unsuitable for wholesale supply to the grid due to the problems of intermittent supply.

But Gaelectric says the Compressed Air Energy Storage (CAES) facility planned for Larne would maximise the potential of renewable power, whilst stabilising electricity prices and emissions.

It should allow wind energy to be integrated onto the grid more quickly and efficiently, boosting employment in businesses that construct and operate wind farms.

The technique uses off-peak power to compress air into an underground geological storage vessel, such as a depleted gas field, disused mine or, in this case, a salt cavern.

The compressed air is later released to generate peak power at times of higher electricity demand.

It means wind energy captured at night won’t be wasted but can be held and used to smooth out variations in supply of wind.

Keith McGrane, head of offshore energy and energy storage at Gaelectric, said: “One of the greatest challenges to unlocking the potential of wind power is to match generation with periods of peak demand.

“Gaelectric intends to deploy compressed air into underground geological caverns in the Larne area as a means to store energy generated from wind, for release during periods of peak demand, or as required by the grid operator. Such technology has the potential to revolutionise renewable power generation from wind.

“Larne is uniquely positioned to have a CAES plant built, given the presence of the underground salt layers. Air storage is at the cutting edge of

new energy markets and Northern Ireland has the opportunity to lead in this field.”

So far, there are only two other CAES plants in the world — one built in Germany in 1978 and one in the USA, built in 1991. However, Mr McGrane pointed out that underground energy storage is nothing new.

“Today, approximately 400 gas storage plants exist beneath the ground in the United States,” he said.

“As such, the deployment and operation of energy storage in salt deposits is well established and is extremely safe, involving the storage of air and not natural gas at depths of 500 to 1,000 metres underground.”

Welcoming the announcement, Professor Neil Hewitt, Professor of Energy and Director of the Centre for Sustainable Technologies at the University of Ulster's School of the Built Environment, said: “The increasing deployment of renewable energy raises the spectre of a conflict between the availability of renewable energy and the demands of society.

“Energy storage is proven to be able to reduce both the peaks and troughs in demands, leading to higher efficiency supply-side operations.

“The current annual £21bn global energy storage market is set 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 the largest potential.

“As the unpredictable nature of wind power currently limits share of supply to the electricity network, storing excess energy for later release enables a smoother, more predictable and therefore a more lucrative electricity supply.

“This will in turn reduce the short cycling and standby of fossil fuel electricity generation plant thus reducing maintenance and running costs, decreasing the reliance on imported fossil fuels and increasing carbon reduction.

“Gaelectric are to be commended in their innovative large scale approach which is complementary to the leading edge energy storage research at the University of Ulster which focuses on the role of the supply side and in particular the built environment at an energy store.”

The exact location of the facility has yet to be decided and will depend on where the best salt lies, Mr McGrane said.

“It would be deployed in the most suitable salt beds considering all planning requirements,” he added.

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