The bitter debate over the giant wind farm proposed for Lewis has dominated the island's political agenda for four years and has sharply divided local opinion.

The island's MP, Calum Macdonald and an MSP, Alasdair Morrison, are both held to have lost their seats because of their support for it.

The basic issue has been whether the undoubted environmental price would be worth paying for much-needed jobs and local investment.

If the development went ahead, there would be 88 miles of road, eight electrical substations, 19 miles of overhead cables, 137 pylons, 18.3 miles of underground cables, and five rock quarries.

But it could also mean £6m a year in local community benefits, multimillion-pound leisure and sporting facilities in peripheral communities, plus at least 300 jobs - all helping to stem the tide of chronic depopulation.

Lewis Wind Power, the company formed by energy giants Amec and British Energy, applied in 2004 to build a 234-turbine wind farm on land across the three most northerly Lewis estates: Galson, Barvas and the Stornoway Trust Estate. Just more than a year ago the proposals were scaled down to 181 turbines.

Comhairle nan Eilean Siar (Western Isles Council) voted overwhelmingly to recommend it a year ago.

However, local campaign group Moorlands Without Turbines claimed 17 measures of island opinion had shown consistent opposition, and highlighted a public opinion survey in the Stornoway Gazette in December 2006 which found 91% opposed.

In addition, around 5000 official objections from Western Isles residents were logged.

The fact the developers were big business, in contrast to the giant development being pursued for Shetland by the island's council, seemed to add to the sense of Hebridean grievance.

But much of the opposition on Lewis had been due to the proposed location of the development. Much of the interior of the vast Lewis moorland had been designated as a Special Protection Area (SPA) and thereby protected by European law. So the giant turbines would be sited about a mile from communities to the north and west of the island.

But even this location was seen to threaten designated sites, as Scottish Natural Heritage made clear: "As the proposal sits largely within the Lewis Peatlands SPA, and adjacent to the Ness & Barvas SPA, SNH has a duty to advise the Scottish Executive if the proposal is likely to have a significant effect on the sites," the heritage body said.

SNH's opposition to proceeding with the wind farm was backed by environmental charity RSPB, which said: "Allowing a development of this scale to go ahead on a Special Protection Area for birds could put at risk the entire European network of protected wildlife sites."

Islanders have been equally passionate on the other side of the debate, seeing the development as key to a new-found economic prosperity.

Indeed, there is deep sense the renewable energy revolution could be to the Western Isles what oil was to Shetland.

There are other proposals in the pipeline, but this was to be the biggest. The £6m-per-annum revenue would have been split among crofters, landowners and the communities of the Stornoway Trust, Barvas and Galson estate lands.

Meanwhile, the Western Isles Development Trust (WIDT) would get about £1m.

But the community trusts and WIDT would be given the chance to take their annual dividend or cash in their shares for 15% ownership of the whole wind farm.

Opponents argued that Amec and British Energy were only in it for huge profits.

A year ago, Councillor Angus Graham, a staunch supporter of the project, argued there should be a little less passion in the debate: "We are not talking about dumping nuclear waste that will be contaminating our island for centuries.

We are talking about wind turbines which will be taken down eventually. It is just a question of judgment. There is no moral high ground," he said.

The pros and cons

The proposed Lewis wind farm aimed to produce approximately 6% of the UK's 2010 renewable energy target and more than 36% of the Scottish Government's target of the same year. The 651.6 MW capacity would supply enough green energy to meet the average domestic electricity requirement of more than 20% of Scotland's population, based upon the 2001 census. It would create 300 jobs during the four-year construction programme and another 71 posts to operate the wind farm. It was calculated it would bring in £6m in community benefits.

The European designation of much of the island moorland as a Special Protection Area (SPA) means it is supposedly protected by European law against harmful developments. The wind farm proposal sits largely within the Lewis Peatlands SPA and adjacent to the Ness & Barvas SPA. The RSPB argued turbines are not the best environment for internationally important species such as red and black-throated divers, golden eagles, merlins, golden plovers, dunlin and greenshank. The development would create 88 miles of road, eight electrical substations, 19 miles of overhead cables, 18.3 miles of underground cables, 137 pylons and five rock quarries.