Sub-Sea Habitat Cable Repair

The Challenge

Traditional sub-sea cable repair methods involve identifying the cable fault location using basic on-shore measurement techniques before lifting the cable onto a suitable vessel to carry out a repair. This approach is costly and can potentially cause further damage to the cable during the lifting exercise. Insurance companies report that there is at least one insurance claim on every marine renewable energy project and claims associated with damage to inter-array cabling or main export cable either during installation or operation account for over 80% of such claims. Currently, all the main competitors only offer a cable lift and repair solution and ESB began investigating whether there was an alternative sub-sea cable repair solution that could provide a quicker, cheaper and technically robust solution that would be a potentially disruptive technology in a growing global market.

The Solution

ESB engineers developed this innovative technology based on the principle of a Habitat which is lowered to the sea-bed and used as a safe working environment to carry out jointing repairs while the cable remains in-situ on the sea-bed. The cable repair is undertaken by specialist marine engineering diving resources that are trained in cable jointing techniques. The cable jointing operation is remotely supervised by marine engineers on-board the cable repair vessel providing a fully audited and certified cable repair service. In addition, distributed temperature sensing technology enables the identification and location of cable faults with a high degree of accuracy further reducing the time and effort involved in sub-sea cable repair. The technology was used to successfully repair the Moyle Interconnector between Northern Ireland Scotland and the electricity cable between Galway and the Aran Islands off the west coast of Ireland. In both projects the Habitat technology yielded significant cost savings over conventional cable repair methods.

The Benefits

The Habitat cable repair solution avoids the need to raise the cable onto a vessel to effect repairs and the resulting potential damage to the cable. It dramatically lowers the cost of cable repair and is significantly cheaper than traditional methods, utilising smaller vessels, reducing environmental impact and is faster at delivering repairs. It also has potential use in inter-array cable jointing during off-shore wind farm installation as well as ensuring optimal cable performance through continuous temperature monitoring of the cable during operation. The sub-sea cable Habitat has the potential to offer certified OEM jointing services endorsed by insurance underwriters to service this growing market with a unique patented offering.

The Future

ESB has engaged with all large-scale cable manufactures in a market soundings exercise and there is strong interest in the technology. The submarine cable industry is forecast to grow by 21% per annum to 2030 driven by significant expected growth in off-shore wind of 115GW by 2030 and up to 200GW by 2040. The global marine renewables cable market estimated value £13.6bn by 2028 and £3.64bn in UK alone. ESB is now focused on commercialising this technology and is developing options to deliver this unique service offering which has applications in renewables, fibre and the oil and gas sectors.