Innovative Orkney tidal energy project completed

Orkney's reputation for marine energy expertise has been enhanced after a unique cable laying project comes to a successful end.

The final phase of a major project to investigate cost-effective methods of cable laying for tidal power arrays, with the aim of helping accelerate development of the marine energy industry, has been completed in Orkney.

The scheme has also highlighted the special skills and services available within Orkney's marine energy supply chain.

Orkney tidal array cabling project operations - image by Colin Keldie

Funded by Scottish Enterprise, the £2.4m Tidal Array Cabling Solution project was launched in December 2013 to develop and demonstrate efficient methods of locating, securing, protecting and retrieving cables for tidal energy arrays.

Stromness based energy and environmental consultancy Aquatera Ltd was one of a number of companies that took part in the initial concept development stage of the project in 2014, subsequently being awarded a contract to undertake two demonstration projects.

The first of these, completed last year, saw a team led by Aquatera successfully deploy a unique, 50 metre long, rigid ‘U-tube’ cabling protection structure - designed by Jee Ltd - at the European Marine Energy Centre’s Shapinsay Sound tidal test site in Orkney. This is believed to be the longest fixed sub-sea structure in the world installed to date at a tidal site, with its deployment involving an innovative arrangement of vessels.

Orkney is a focal point for the tidal energy industry - image by Colin Keldie

The second and final phase of the project was completed over the winter of 2015 at a specially licensed site in the fast moving tides of Hoy Sound, also in Orkney.

The programme of work successfully tested over 10 different technological and procedural innovations within a ground breaking set of cable laying trials. The key areas of innovation included the type of cable lay vessel, the decking arrangements, the mooring arrangement and materials, surveying techniques, the use of a novel cable locating and protection system and the proving of cost effective cable layout and cable deployment and recovery techniques.

Aquatera has led and managed the year long programme of design, fabrication, deployment, testing and reporting activities, with essential collaboration and support from Stromness based Green Marine, who also provided the specialised GM700L heavy lift barge. The barge was adapted for use as a cable-laying platform using a movable modular decking system installed between the barge hulls. Other key contractors in this second phase of the project included JGC (fabrication), LUPUS (structural design) TTI (mooring analysis) and Orcades Marine (procedures and onsite services) with Roving Eye, Sula and Triscom providing deployment support services.

Image by Colin Keldie

Daniel Wise, Head of Offshore Technology with Aquatera, said: “Establishing a safe, cost-effective and accurate means of laying cables in demanding tidal environments has been identified as a major challenge for the tidal energy sector. Aquatera has been working on a range of solutions to this challenge over the last five years or so and was delighted to get the opportunity, through the support from Scottish Enterprise, to work alongside our delivery partners to prove that the solutions we had developed would work in reality. The results that we have achieved within just one year have been outstanding and give us real confidence that we can now further develop an approach to cabling design, cable laying and cable management that will transform the economics and reliability of tidal energy.”

Neil Ferguson, Senior Executive, Energy and Clean Technologies, Scottish Enterprise, said: “We are delighted that the demonstration of Aquatera’s tidal cabling solution went so well and offer our congratulations to Aquatera and their project partners for their highly professional approach to turning R&D into practical reality. This success is exactly what Scottish Enterprise had hoped would emerge from our Tidal Array Cabling Solution Project, developing effective solutions to key issues for the growing tidal energy industry and contributing to the drive to reduce costs."

Find out more about Orkney's reputation as the energy islands. Newsletter

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