Communications giant BT plans to build a series of wind farms across the UK as part of a £250m plan to generate up to one-quarter of its UK electricity requirements by 2016.

Sites in Orkney, Shetland and Cornwall will be first to be tested in the scheme which represents the UK's biggest corporate wind-power project outside of the energy sector.

BT is one of Britain's biggest consumers of electricity, with an annual requirement of around 0.7% of the UK's entire consumption. It is hoped the network of turbines could generate a total of 250 megawatts of electricity, enough to meet the power needs of 122,000 homes.

This would prevent the release of 500,000 tonnes of CO2 each year compared with coal generation - equivalent to a quarter-of-a-million return air trips to New York.

The company is currently identifying exposed and windy sites on or adjacent to BT-owned land for development with the aim of generating power from 2012.

Subject to planning consent and suitable sites being secured, BT's wind farms would have a total installed generating capacity of around 100 megawatts by 2012, equivalent to 50 turbines, with the remaining 150 megawatts targeted by 2016.

Andy Riley, the project director, told The Herald yesterday that any given site might only have half-a-dozen turbines. "We have looked at something like 5000 properties that BT has across the UK, but of course most are struck out right away," he said.

"We don't know how many we will end up with yet, but there won't be one 100-megawatt project but a number of smaller projects."

The sites in Shetland, Orkney and Cornwall were the first to get the process started but others would be following, Mr Riley said.

A queue formed yesterday to welcome BT's announcement, breached only by voices from Orkney.

John Swinney, Cabinet Secretary for Finance and Sustainable Growth, said: "I am encouraged to hear about projects such as BT's, which are designed to safeguard supplies of clean, green energy while reducing carbon emissions.

"We want to see the right onshore wind developments in suitable locations that do not adversely impact on the environment and help us deliver a greener future for Scotland."

Jonathon Porritt, co-founder and programme director of Forum for the Future, agreed: "This is an enormously significant decision for BT - and for every company that sees BT as a recognised leader on sustainability issues."

But Colin Kirkpatrick, of the Orkney Skyline Concern group, said: "I find BT's actions symptomatic of a massive wind-farm free-for-all in Orkney because of a complete lack of concrete policy in place regarding wind turbines.

"There are plans for developments all over Orkney. I am fed-up living on an island that is a laughing stock."