Electricity giant SSE (Scottish and Southern Energy) is to launch a public consultation on burying subsea cables to islands off the Shetland Mainland, which could mean a price rise to users.
Until now, cables have been laid on the surface of the seabed but in future this may have to be changed.
This follows the adoption in March last year of the National Marine Plan (NMP) for all activities in Scottish waters out to 200 nautical miles to achieve “clean, healthy, safe, productive and diverse seas”.
The plan covers submarine cables throughout Scotland, which are at present laid directly on the seabed but may have to be protected, requiring “significant expenditure”.
This cost will have to be paid by customers in the Scottish islands and across the north of Scotland, and should see bills rise.
The programme of protecting the cables, which could see them being buried for part or all of their length – not all cables need to be protected “end to end” – is a rolling one which will come into force when cables need to be replaced.
One third of all Scottish island cables are replaced every eight years, and usually happens when they have been in place for 30 to 40 years.
The branch of SSE which deals with cables is SHEPD, which proposed to spend £44 million over the next eight years on replacing 112 kilometres of submarine cables.
That figure was based on surface laying. But the new rules mean that if the whole length was to be protected it would cost £300 million.
In Shetland, it has already been agreed that the cable from Lerwick to Bressay will be buried 15 metres under the seabed. Burying cables requires the use of specialist vessels and equipment.
Other cables due for replacement are between Yell and Unst, where two would be replaced, and across Yell Sound, between Mossbank and Yell, where there are two cables, one of which would be replaced.
The cost of installing protected cables would mean an increase on the part of the electricity bill which covers distribution, which at present accounts for 16 per cent of the bill.
Although there would be an expense in protecting cables, there would be an eventual saving to SSE in costs of damage to cables caused by boats, or abrasion by weather. Protected cables should mean greater reliability and SSE aims to get as many cables protected as possible.
The public consultation is being carried out in response to the NMP. It will focus on the impact on customers and fuel poverty, the environment and “users of the marine environment” such as the fishing industry.