Timetable for Western Isles' electricity interconnector
A subsea cable needed to carry electricity generated on the Western Isles to the mainland could be constructed by December 2020.
Scottish Hydro Electric Transmission, a subsidiary of SSE, has set out a timetable for the interconnector.
It hopes to submit a needs case to the energy regulator Ofgem this year and start construction in 2017.
Western Isles local authority, Comhairle nan Eilean Siar, has welcomed the timetable.
Leader of the comhairle, Angus Campbell, said it was the first time in years a "clear and concise" set of goals and milestones had been set out.
Costing an estimated £780m, the interconnector would export electricity generated by wind farms and other renewable schemes on the islands to the mainland for distribution.
It would stretch about 50 miles (80km) from Gravir on Lewis to Ullapool on the north-west coast of mainland Scotland.
There have been discussions about subsea cables linking islands energy projects with the mainland since 2001.
In October 2014, the backer of plans for the largest wind farm on Lewis in the Western Isles pulled out of the project blaming delays in laying the cable.
The French energy giant GDF was to invest in the planned 39-turbine scheme on the Eisgein Estate.
GDF, along with other renewable energy developers, had been expected to contribute to the cost of the interconnector.