A revised business case for building a Minch interconnector is finally expected to be completed this summer.
An application for full planning application will also be lodged in June.
UK energy regulator Ofgem requires the business analysis document before considering approving the sub sea cable which would export wind and wave farm electricity from the Western Isles to mainland markets.
Scottish and Southern Energy (SSE) said it intends to lodge the business case which looks at the economics and commercial demand for the link this summer.
At the same time it will apply for planning permits to lay the submarine electricity cable on the sea bed Arnish on Lewis and Dundonnell, south of Ullapool.
All new windfarm projects in the islands hinge on the interconnector being built to enable electricity to reach southern markets.
In 2012, Ofgem rejected the first investment plan from Scottish and Southern Energy
(SSE) -
It questioned why estimated costs had almost doubled from the initial £400 million projections.
SSE then cancelled the contract to manufacture the cable.
At the time the energy giant said it would submit a fresh economic assessment of the project to Ofgem.
Now six years later it seems the investment request will be finally lodged.
The plans were also suspended in 2010 because the developers at the time did not financially back the link and SSE said it could not conclude a contract for the supply of the necessary electricity cable.
Developers would not underwrite the cable until the actual level of future subsidy payments are confirmed.
Transmission charges increase the further from the point of use so it is about 60 times more expensive to export renewable electricity off the islands and down the grid network compared to a generator in the south of England.
SSE said it is “currently analysing the economics” of the link based on a range of generation profiles to identify the “tipping point” to justify the investment.
This is the point at which the cost of the investment is exceeded by the benefits of the renewable energy supplied to energy consumers.
The energy giant is holding a consultation event in Stornoway today to seek the views of the local community.
Subsea cable planning application to be finally lodged
12 March 2018