The proposed sale is dependent on a successful listing and fundraising by wind-farm investment fund Greencoat UK Wind.
SSE will invest up to £43 million of its sale proceeds in this new fund. SSE's investment will be scaled back from £43m if Greencoat UK Wind's fundraising is over-subscribed, but will not fall below £10m.
The UK Government, through the Department for Business, Innovation and Skills, has committed to subscribe for £50m of shares in Greencoat UK Wind.
SSE has agreed to sell its 50% stake in the 72-megawatt Braes of Doune wind farm, near Stirling, and its 100% holding in the 28.5MW Tappaghan site in Northern Ireland to Greencoat UK Wind. It has also agreed to sell its 100% stakes in the 6MW Carcant wind farm in the Scottish Borders and 9MW Bin Mountain site in Northern Ireland to the fund.
Scottish Hydro-Electric owner SSE agreed in summer 2011 to sell its 50% interest in Braes of Doune for £61.3m to a fund managed by Climate Change Capital, but this planned transaction fell through.
SSE said yesterday it would continue to have the operation and maintenance contract for all four of the wind farms involved in its deal with Greencoat UK Wind.
It added that it had, as part of the deal, entered into agreements to purchase the power from three of the wind farms – Tappaghan, Carcant, and Bin Mountain – output totalling 43.5MW.
SSE noted a "third party", Centrica, already had a power purchase agreement (PPA) for Braes of Doune. Centrica owns the other 50% of Braes of Doune.
Greencoat UK Wind, which has also agreed to buy stakes in the Little Cheyne Court onshore wind farm in southern England, and the Rhyl Flats site off the coast of North Wales from German power company RWE, aims to raise at least £205m in its flotation, including the SSE and Government stakes. It has an option to increase the total size of the share issue by up to £55m.
SSE finance director Gregor Alexander said: "This agreement represents the latest step in a programme of acquisitions and disposals to optimise our wind farm portfolio.
"Fundamentally, SSE owns generation capacity to meet the electricity needs of its own customers, which is why we were pleased to be able to establish new PPAs before disposing of these assets."
He added: "The proceeds from these disposals will support our investment in new renewable assets in the coming financial year."
Greencoat UK Wind will be run by executives from "cleantech" and renewables-focused investment management firm Greencoat Capital LLP, and chaired by former Caledonia Investments chief executive Tim Ingram.
Laurence Fumagalli, investment manager at Greencoat Capital, cited plans to market the new fund to private as well as institutional investors. He said: "We would fully expect to be on the road in Edinburgh and Glasgow."