The wind farms are expected to cost about �250m to build

BT hopes to place two test farms on Orkney and Shetland, with a third based in Cornwall.

It is hoped the �250m project will generate up to a quarter of BT's electricity requirement by 2016.

The move was welcomed by the Scottish Government, which said it was "encouraged" by the project.

The wind farm scheme will represent the UK's biggest corporate wind power project outside of the energy sector.

BT said the project would safeguard future supplies of clean, green energy for the company as part of its strategy to reduce carbon emissions.

Organisations must reduce carbon in ways that make business sense Brendan Dick BT Scotland

It has applied for planning permission for test masts at Wideford Hill Radio Station in Orkney and Scousburgh Radio Station in Shetland.

BT is one of Britain's biggest electricity users, with an annual requirement of about 0.7% of the UK's entire consumption.

Its wind farms proposals would aim to generate a total of 250MW of electricity, enough to meet the power needs of 122,000 homes.

The turbines would also prevent the release of 500,000 tonnes of CO2 each year, compared to coal generation.

'Green energy'

Brendan Dick, director of BT Scotland and a member of Scotland's Climate Change Business Delivery Group, said: "Organisations must reduce carbon in ways that make business sense.

"BT has already achieved a 60% reduction in its carbon emissions, and is committed to reducing them further to 80% by 2016.

"Our wind energy plans will play a significant part in reducing our footprint and in turn help Scotland, where we are a major employer with an extensive supply chain, to meet its commitments."

John Swinney, cabinet secretary for finance and sustainable growth, said the project offered further proof of Scotland's "vast potential" to generate electricity from renewable energy.

He added: "We must be in a position to maximise our resources, which is why the Scottish Government will build an energy strategy which will include the whole renewable mix - including wind generation.