Scotland to build world's first 'wind farms under the sea'

By Jenny Haworth (Environment Correspondent), News.Scotman.com, 29 September 2008

SCOTLAND has taken a major step towards leading the way in marine renewable energy with the announcement that the world's first tidal farms could be built within three years.

Two tidal projects, each with up to 20 turbines, could be installed on the seabed in the Pentland Firth and the Sound of Islay. A third is planned off the North Antrim coast in Northern Ireland. The aim is that all the underwater turbines would be constructed in Scotland, kickstarting the renewables industry in this country.

ScottishPower Renewables will apply for planning permission for the three tidal projects next summer. If permission is granted, they would be the first commercial underwater tidal turbine farms built anywhere in the world.

The structures stand 30 metres tall and can work as deep as 100 metres. The 20-metre blades would turn at least 10 metres below the surface to avoid shipping, developers said, and the zones would be off-limits to trawlers for safety reasons.

ScottishPower said tests in Norway proved the blades moved slowly enough for marine life to avoid them.

Scotland, which aims to reduce its greenhouse gas emissions by 80 per cent by 2050, has the best tidal resources in Europe and it has been calculated that at least a third of Scotland's energy demand could be met by tidal renewables.

The tidal farm sites would have a combined output of 60 megawatts, enough to power 40,000 homes in Scotland and Northern Ireland. If planning approval is granted, ScottishPower Renewables says the projects could be operational by 2011.

The company is also hoping to build a factory in the north-east of Scotland where all the turbines will be constructed, and the projects would be expected to bring hundreds of jobs.

Keith Anderson, the director of ScottishPower Renewables, said this was Scotland's chance to become the global leader in a new renewable energy industry.
He said Scotland has the best tidal resources in Europe, with the Pentland Firth alone containing enough energy to meet a third of Scotland's power requirements. "The rapid technological advance of tidal power has been startling and is now allowing us to progress plans for substantial projects delivering major environmental and economic benefits," he said.

"Tidal power is completely renewable, being driven by the gravity of the sun and moon, with no carbon dioxide emissions, plus the added benefit of being entirely predictable."

First Minister Alex Salmond, who will visit Caithness, near the potential site of the tidal farms, described the announcement as "significant". He said: "We have an estimated 25 per cent of Europe's tidal resource and 10 per cent of its wave potential. That is why this announcement is so significant."

Before it can be deployed, a £6 million prototype will have to be tested for about a year in Scottish waters, probably off Orkney.

Engineers rising to the challenge of harnessing tidal power

THE tidal farms will use a machine known as the Lànstrøm device, which was invented in Norway and has already gone through four years of successful testing.
Even though the devices seem likely to be the first to be used in a large-scale commercial tidal farm, many other machines are in development in what is set to become a very competitive market.

Marine Current Turbines, based in Bristol, installed a 300kw tidal turbine called Seaflow off Lynmouth, Devon, in 2003.

It's a two-bladed rotor connected to an electrical generator mounted on a single steel tower drilled into the seabed.

Irish firm OpenHydro Group has developed the Open-Centre Turbine, which has a single rotor. A single prototype turbine was installed at the European Marine Energy Centre in Orkney in 2006. In May 2008 it became the first tidal device to export power on to the UK grid.

The Engineering Business, based in Newcastle, is developing the Stingray tidal generator, which uses the flow of the tide over a hydroplane, similar to an aeroplane wing, to generate electricity. In 2002 the 180-tonne, 150kw machine was tested in the Yell Sound, Shetland.

SMD Hydrovision, based in Tyne and Wear, has developed the TidEL concept, which consists of a pair of contra-rotating 500kw turbines, mounted together on a single crossbeam.

The unit is buoyant and tethered to the seabed, allowing it freedom of movement. The turbines can automatically align themselves downstream of the tidal flow as it changes during the day.

IN NUMBERS

• 40 - Turbines that could be built in Scottish waters by 2011.
• 40,000 - Homes that could be powered by the three turbine farms.
• 80 - The percentage of the UK's potential tidal power in Scottish waters.

All rights reserved ©2008 Johnston Press Digital Publishing

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