Electricity regulator Ofgem has rejected current plans for subsea links between two Scottish islands and the mainland.
Scottish and Southern Energy Networks (SSEN) wanted to build a 600MW underwater cable between Shetland and mainland and a similar link from the Western Isles.
Subsea cables would have connected planned wind farm projects on the islands, allowing them to export electricity to the rest of the UK.
Ofgem said it was “unable to approve” the links after the wind farms failed to win UK Government subsidies, however said it would “welcome” revised proposals.
The regulator said: “It encourages SSEN to submit revised proposals for both transmission links, including establishing more certainty for consumers that the windfarm projects will go ahead.
“Ofgem is engaging with SSEN to secure evidenced and realistic proposals from them and will endeavour to consider them as soon as possible.”
SSEN managing director for transmission Rob McDonald said: “We welcome Ofgem’s continued commitment to provide a way forward for both the Shetland and Western Isles transmission links.
“It is now critical that all parties work together to provide the information Ofgem require at the earliest possible opportunity.
“Ultimately, a successful outcome will depend on renewable developers on both island groups demonstrating that sufficient generation will progress to underpin the transmission investment cases.”