Mainland Shetland - Papa Stour Subsea Cable Replacement
We are planning the installation of a replacement subsea electricity cable for customers on the island of Papa Stour in Shetland in late August/early September 2024.
In January 2024, the subsea cable taking electricity from Mainland Shetland at Melby, across to the island of Papa Stour, developed a fault.
We immediately installed temporary generators to restore the power supply to the island, whilst investigating the cable fault. This involved specialist survey works and analysis of the data by our subsea team. A site visit was carried out, and the decision was made to replace the cable and ensure a long-term resolution to the failure. This will mitigate any potential risks of further damage to the existing cable during repair works.
These plans to replace the cable will be progressed as soon as is practically possible; before we can start work, we need marine licensing and other consents, and we also need to be able to secure specialist contractors and the installation vessel.
In the meantime, all properties on Papa Stour will continue to be supplied via backup generation, with members of our team in Lerwick carrying out regular inspections and refuelling of the temporary equipment on the island.
We have produced some commonly asked questions to answer your questions about the project. This page will continue to be updated when we have further information. If you have any questions in the meantime, please email submarinecables@sse.com.
Commonly asked questions
The initial land and marine survey works have taken place to assess the location and condition of the subsea cable and the shore ends. The land works will take around 3 weeks, and the subsea cable installation around 2 days. Additional vessel time may be required to support installation of cable protection and stabilisation measures such as cast iron split pipe and rock bags (2-3 weeks).
The cable we use in our current subsea projects is a more advanced, double armoured cable than used back in 2008 when the previous cable was installed. It has a polyurethane coating with a double layer of steel wire armour to prevent wear and will be stabilised on the seabed with rock bags to prevent movement.
The cable replacement is planned for late August/early September, subject to marine licensing and other consents, and securing specialist contractors and the installation vessel. As soon as we can confirm more specific dates, we will advise the community.
We are still assessing the marine surveys and the cable route will be confirmed as soon as possible, but it’s likely it will follow a similar route to the current cable and link to existing land-based infrastructure.
The subsea cables we currently install have a life expectancy of 25-30 years, depending on tidal currents and the landscape of the seabed.
We hope to bring plant and machinery to Papa Stour via landing craft and will confirm this as soon as we can. We will need to bring in an excavator at Melby and we are in discussions with a local civils contractor who knows the area to agree the best way forward e.g. using a trailer. All plant and equipment in Melby will be stored in the laydown area, and there will only be one mobilisation and one demobilisation during the operational process. Disruption to both communities will be kept to a minimum whilst the works take place.
SSEN will continue to provide electricity to Papa Stour via temporary generators until the new cable is installed and tested. Once tests have been completed, there will be a power outage of around 1-2 hours whilst the electricity supply is switched over from the generators to the subsea cable. SSEN will advise residents in advance of the date and time.
This option will be available for Papa Stour, and SSEN has provided further information to the community about how they can get connected. SSEN has advised that any connection will need to be arranged directly with a fibre supplier, but the infrastructure in the form of the fibre cable running through the new subsea electricity cable will be in place.
