Work has started to replace cables that provide an essential power lifeline to Caldey Island.

It's a £1.3 million project to upgrade and replace approximately four kilometres of sub-marine cable.

Like many small islands, Caldey is dependent on a reliable electricity supply from the mainland, and because the two existing underwater cables are almost 30-years-old and in need of renewal, it's hardly surprising that such an unusual and specialist project has required months of careful planning.

Chris Gunner, Western Power Distribution's team manager for the area, explained: "For the past year, we have been working and consulting with a number of agencies, including Pembrokeshire National Park, the County Council, Crown Estates, the Environment Agency and of course the island's business manager.

"The existing cables were laid back in the early 1980s and have now started to deteriorate. They have an average life span of roughly 20 years, so they are due to be replaced, but it's quite a complex project and there are a lot of factors to consider.

"For instance, we are not only restricted by tidal currents between the island and the mainland, but also by the weather, which has been a major factor. We've also had to make sure that local traders and pleasure boat operators are fully informed and included in our consultations.

"Because we needed one length of submarine cable four kilometres long, we worked closely with cable specialists to get exactly what was needed for the job. We've also had to order a special type of boat to carry the cable because of its size and weight," continued Chris.

The cable will lie approximately 11 metres below the surface and the intention is to retrieve as much of the old cable as possible.

The new cable arrived at Pembroke Dock from Italy about about three weeks ago, and the specialist vessels arrived in Tenby last week.

Currently, some smaller support vessels are carrying out surveys of the sea bed between Caldey and the South Beach. Anchor points will then be installed on the island and on South Beach.

Added Chris: "We hope to be able to lay the cable early next week. The weather needs to be stable and the tidal movements should be much lower by then, so the work can commence to lay the cable on the sea bed.

"Our contractors, Balfour Beatty, have had to carry out excavations and install cable to connect the overhead line network to the submarine cable which will be terminated above the high water mark. WPD apprentices, craftsmen and technicians have also been installing new automation equipment on the island and the South Beach.

"We are mindful that Caldey is well known for its magnificent expanse of sandy beach so it's quite a challenging exercise. We want to ensure that we cause as little disruption and upheaval to the landscape and beach as possible, and we certainly want everyone to feel satisfied with the job once it's completed by the end of December, depending on weather conditions," Chris concluded.