Aegir wavefarm could bring a lot of work to Shetland, say developers

The proposed £60 million Aegir wavefarm off Shetland could generate considerable work for the islands, including a dedicated maintenance team for the Pelamis machines and contracts for tugs and workboats.

Aegir hopes government consent will come through in 2013 and the wavefarm can be in place off the south-west between Burra and Spiggie to start generating the following year.

If the experimental venture to produce between 10 and 20 megawatts of power is successful it could persuade the Swedish energy giant Vattenfall to go large, siting many arrays of wave energy converters further off Shetland’s coast to create an enormous power station generating hundreds of megawatts.

When the company visited in December it said it might one day need its own interconnector cable to carry power for sale to the UK and beyond. Currently it is entirely dependent on the Viking Energy windfarm going ahead and using space in its cable, due in 2014, to carry its wave power.

The Shetland venture will see between 14 and 26 so-called sea snakes, the new generation Pelamis P2. Aegir project manager Andrew Scott said further research work would lead to the footprint being reduced to just a couple of square kilometres. At the moment it is likely to be somewhere in the northern part of the zone, closer to Burra, in water depths of 60-80 metres, depending on various factors including fishing grounds and wildlife.

A dedicated base would be developed in a sheltered voe where the 180-metre-long P2 machines will be towed for monitoring and all their maintenance, done not from a quayside but in the voe from pontoons and workboats. No site has been selected yet but Clift Sound and Gruting Voe on the West Side are in the frame.

According to Mr Scott, one of the beauties of the Pelamis machine is the ability to disconnect a single one from site in just 10-15 minutes to take inshore for work, whereas repairing or maintaining an offshore wind turbine is hugely expensive, time consuming and cannot be done in bad weather.

The workboat Voe Viking, owned by local firm Delta Marine, is already on permanent hire to Pelamis and another, Voe Chief, has been helping with the sea trials of the first P2 in the Firth of Forth prior to being towed to Orkney from the Pelamis base in Leith this week.

It is to be tested at the European Marine Energy Centre (Emec) for its owner power company E.ON for three years, producing power for the grid.

Pelamis already has a team of six people employed in Orkney to be its maintenance crew for the P2, which includes its first local employee. The same would be done in Shetland for the Aegir project although it would appear that more people would be required for up to 26 machines.

The P2 machines can power around 500 homes, generating up to 750 kilowatts each. Mr Scott said that in researching sites around Shetland they chose to avoid areas of strong tidal currents, which could drag the devices away from their optimum position head-to-wind at their moorings and set 250-300 metres apart. During gales they dive into the oncoming waves, avoiding the extreme peaks of energy, which helps ensure that they do not have to stop generating.

The Aegir team has settled on the beach at Maywick as the preferred site for the power cable to come ashore, which is where the Faroese telecoms cable is buried. A small substation will feed the electricity into the Shetland distribution grid, introducing enough power to potentially provide for 13,000 homes.

A six-strong team from Aegir was in Shetland this week for two roadshows in Scalloway and Lerwick but there was little interest from the public with less than a dozen people attending.

There will be more opportunity over the next two years as Aegir conducts its environmental impact assessment before submitting its formal plans to the Scottish government for consent. All marine power developments rated over one megawatt have to be considered by ministers rather than the local planning authority although Shetland Islands Council has an important role to play due to its special powers to control marine developments.

Pelamis has other projects, including reviving its stalled Portuguese venture, and providing a P2 for Scottish Power next year. It has its own project off the Scottish mainland and is scoping one just now off the Western Isles.

Vattenfall representative Kristin Andersen said the company was pursuing projects off the South Mainland and the west coast of Ireland to investigate the best technology for harnessing the waves.  The Irish venture with the government, called Tonn Energy, involves a device called Wavebob.

A crucial date in the calendar comes later this year when Vattenfall’s board will decide whether to approve investment in the wavefarm. She said it would be a significant step for the project and the biggest investment in wave power yet.

Vattenfall is now Europe’s fifth largest generator of electricity and is still ultimately owned by the Swedish state. One of its senior executives, Dr Helmar Rendez, who visited Shetland in December, said Vattenfall intends making its electricity clean by 2050.