The groans of despair could almost be heard floating across the Minch.

It had just been confirmed that the energy regulator Ofgem had sent back for more information Scottish Hydro Electric Transmission Limited's (SHETL) submission on laying an interconnector cable to the Western Isles. It meant one thing: yet more delay after years of expectation.

The fate of this vital link between the mainland and Lewis will decide whether or not the Western Isles can ever reap the much heralded benefits of a green energy revolution courtesy of its natural wind, wave and tidal power assets.

A joint UK/Scottish Government study published in May estimated that by 2030, the number of green energy jobs created could increase to more than 3500 on the Western Isles. This is a truly transformational prospect in a place where there are only about 9600 full-time equivalent jobs, along with 1700 people self-employed.

What SHETL (a subsidiary of energy giant SSE) was submitting to Ofgem was a case justifying electricity consumers across Great Britain – not the UK – being charged, in the long term, for the money it is proposing to spend on the Western Isles project.

And it is quite a lot of money. SSE revealed last November that it would cost £775 million to lay the cable and establish the infrastructure, a massive 65% increase on the £490m previously estimated.

Not everyone can understand where the £775m figure comes from, not least when information on cheaper examples from abroad can be readily accessed. One was a new interconnector system installed between mainland Spain and the island of Majorca last year. It appears to have cost less than half the price of a cable across the Minch, despite the distance being three times greater.

Of course the Mediterranean is not the Minch, but other recent cabling projects across the planet do seem to suggest, to the layman at least, that SSE's figures are not the cheapest.

In its letter Ofgem is telling SSE it needs a great deal more information on costs. But some on the islands are questioning SSE's commitment. The first murmurings of a conspiracy theory which holds that SSE simply does not want to take this project forward are being heard.

SSE insists nothing could be further from the truth and Ofgem regularly asks for more information. It says the announcement last week that the Department of Energy and Climate Change was going to consult on the subsidy levels necessary ensure renewable energy investment in the islands had set it back.

SSE had anticipated a firm announcement, not a consultation, on the so-called "strike price". This guarantees island producers a minimum level of income. But SSE is confident the final announcement will be made before the end of the year when developers will make a firm commitment to the islands and the case for interconnector can be finalised. Until then, the islands wait.