from Sunday Herald, 19 April 2009
A unique tidal power machine being developed at Strathclyde University could produce enough electricity to replace both of Scotland’s ageing nuclear power stations.
Researchers say that 2,000 underwater turbines tethered to the seabed around the west and north coasts could generate a massive two gigawatts of power. That is more than enough to supply all Scotland’s base load electricity, and supplant power from the reactors at Hunterston in North Ayrshire and Torness in East Lothian.
With the right incentives a series of large tidal turbine farms could be in operation around the Scottish coast by the 2020s, researchers argue, enabling Hunterston and Torness to be closed down without power blackouts.
Tidal power is the holy grail of renewable energy research because it offers potentially huge amounts of energy in a very predictable pattern. Because of the time lag in tides around the coast it could also supply constant power.
Now a team of engineers led by Cameron Johnstone from Strathclyde University’s Energy Systems Research Unit has come up with a new machine which they believe could tap serious amounts of the clean, natural energy soon.
Looking a little like an aircraft engine with two propellers, the device uses the movement of the tides to turn turbines and generate electricity. It has two rotors designed to spin in opposite directions, giving it enough stability to operate in deep waters.
Unlike previous first-generation tidal machines, it will not be fixed to the seabed on a tower like a wind turbine, but moored by a cable. This will enable the device to move with the flow of the tide, like a kite on a windy day.
The device has been christened Cormat, for Contra Rotating Marine Technology. It has already been successfully tested in the sea off Islay, and industrial backing is now being sought for a £1.6 million, 500-kilowatt commercial demonstration.
According to Johnstone, Cormat could be deployed in underwater farms off the Mull of Kintyre, in the sound of Islay, near Skye and in the Pentland Firth. “You could see tidal energy come up to complement and then potentially replace the nuclear power stations,” he told the Sunday Herald.
“This second generation turbine marks a new threshold in tidal energy technology, and could allow us to extract more energy from the sea than ever before.”
If the 500-kilowatt demonstration works, one megawatt machines with 14-metre rotors could start generating electricity under the sea soon after 2013, Johnstone said. It would take approximately 2,000 of them spread up the coast to replace the electricity from Hunterston and Torness.
Hunterston is currently scheduled to be closed in 2016 and Torness in 2023, though their lives could both be extended. They provide more than enough electricity to meet Scotland’s base load requirement.
Johnstone said that he had already had “substantial interest” from private companies in the power, engineering and investment sectors. His design would cost at least 50% less than first generation tidal machines, he argued, because it was relatively simple and didn’t require fixed foundations.
“The need to develop advanced technologies to power homes and businesses has never been more apparent,” he declared: “Scotland's vast natural resources mean we are well-placed to develop and test cleaner and greener systems that can help tackle climate change, as well as increasing sustainable economic growth.”
The Scottish government praised Cormat as an exciting project that helped demonstrate the nation’s “world-leading strengths in harnessing the vast clean, green renewable energy potential off our shores”. Scotland had a quarter of all Europe’s tidal resource, said a spokesman for the energy minister, Jim Mather.
“Scotland simply doesn’t want or need dangerous and unnecessary new nuclear power stations, with soaring decommissioning costs and the unresolved problem of storage of radioactive waste that burdens future generations for thousands of years,” the spokesman added.
“Renewable technologies including wind, water, biomass, wave and tidal, backed up by clean thermal baseload, can meet our energy needs many times over.”
The industry body, Scottish Renewables, pointed out that the predicable nature of tidal energy had big advantages for the electricity grid. “Tidal will become a vital component in Scotland's mix of renewable technologies,” said the organisation’s marine officer, Morna Cannon.
“Currently the sector requires a degree of public funding to help it get on its feet. The level of the renewables obligation funding is crucial, although there are strong views that additional funding is necessary.”
Download a short video of Cormat in action here (2.2MB wmv).
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