Ofgem has turned down a bid by SSEN (Scottish and Southern Electricity Networks) to future-proof the Western Isles’ grid connections by allowing a bigger interconnector than needed to serve wind farms currently in the development pipeline.

The energy regulator announced today (Tuesday) that it has provisionally approved SSEN’s applications for 450MW and 600MW interconnectors with the Western Isles and Shetland respectively.

But Ofgem rejected the network operator’s application for a larger 600MW sub-sea cable that would connect the Western Isles into the mainland transmission network for the first time.

SSEN says its analysis shows that a 600MW link would cost five per cent more to build than its 450MW scheme but provide one-third more new renewable electricity generation capacity.

The Western Isles connector is primarily designed to serve the Stornoway and Uisenis wind farms, proposed on the Hebridean Isle of Lewis, which have a combined generating capacity of up to 369MW.

SSEN wants to build the larger 600MW link in order to stimulate additional renewable projects on the Western Isles.

However while provisionally giving the green light to the 450MW scheme, Ofgem has ruled that there is ‘significant uncertainty’ about whether more than 530MW of capacity will be delivered, the break-even point that it believes will determine whether the interconnector provides value for money for UK consumers.

Colin Nicol, managing director of SSEN, “strongly” urged Ofgem to reconsider and approve the 600MW link.

“A 450MW link would be short-sighted, limiting the potential for community schemes to benefit from renewables expansion. Moving to a 450MW at this late stage also introduces risks and uncertainty which, in turn, could impact on the delivery of a transmission link to the Western Isles.”

The regulator also approved the Shetland project, which is a 600MW subsea circuit that connects into SSEN’s recently completed Caithness-Moray transmission link on the Scottish mainland.

The interconnector, which connects Shetland to the mainland grid for the first time, is being developed to serve the Viking Wind Farm.

Both the Shetland and Western Isles projects have been approved subject to the onshore wind farm projects, which they are designed to serve, receiving support in May’s upcoming contract for difference auctions.

Responding to Ofgem’s announcement, Hannah Smith, senior policy manager at Scottish Renewables, said: “We welcome Ofgem’s minded-to position on the Shetland interconnector – the lack of which has left promising projects effectively locked out of the energy market for want of a network connection

“The decision to approve a smaller connection to the Western Isles – which is in an almost-identical situation – does, however, raise questions about whether consumers now and in the future will be denied access to the islands’ potential for low-cost renewable generation.”

Smith urged Ofgem to consider the potential for increased future green energy generation when making its final decision on the Western Isles link.

Ofgem is consulting on its decisions, which close on 3 May.

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