The Scottish island of Gigha is to be the focus of a £2.5m experiment aimed at solving a major technological problem: how to store energy generated by wind, tide and wave power plants. The project, which will involve building giant batteries containing 75,000 litres of sulphuric acid mixed with vanadium pentoxide, is intended to allow power generated by the island's wind turbines to be stored for later use.

At present, while Gigha's turbines are running, their power is used to run households on the island and excess is transmitted by cable to the mainland electricity grid. When winds are low, and Gigha's turbines do not turn, the grid feeds power to the island. But the cable link has an upper power limit. As a result, much of the island's excess power cannot be transmitted to the mainland and is wasted. The battery project, backed by the Department of Energy and Climate Change, is intended to get round this problem.

"It is not easy to store electricity on a large scale," said Sir John Samuel of REDT, the company awarded the battery contract. "Standard lead-acid batteries generally lose their charge relatively quickly. The battery system we are involved with does not suffer from this problem."

Samuel said the batteries would be able to store enough power to provide the island with 100kW of electricity for 12 hours when winds were low. "The crucial point is that our batteries will be able to be used over and over again," he added.

Scotland's islands and remote highland regions have immense potential for wind power – and, in future, wave and tide power – but suffer because their electricity-cable links are poor and would be immensely expensive to replace. Battery storage systems could therefore help Scotland to reach its goal of meeting all its electricity needs renewably by 2020.