The document is thought to discuss why a subsea cable is needed to carry electricity generated on the Western Isles to the mainland.
Scottish Hydro-Electric Transmission Ltd, which is a division of energy giant SSE, said the 'Needs Case' was part of the regulatory and planning process.
-- Advertisement --
Energy regulator Ofgem will now assess whether the interconnector is efficient and economic.
The project has been hit by a series of delays and an increase in costs has pushed the project's price to an estimated £780m.
The Western Islands local authority, Comhairle nan Eilean Siar, has said major renewable energy projects planned for the isles are not able go ahead without the cable and it welcomed the submission to Ofgem.
If approved, the cable would stretch to about 50 miles (80km) from Gravir on Lewis to Ullapool on the north-west coast of mainland Scotland. Ofgem will now assess the information before a decision is made to allow a financial investment to be made.
(JP/CD)
