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Britain: U.K. Looks To Harness The Tides To Produce Energy

  • Jan Jun

Britain may be lagging other countries as far as using clean or renewable sources for generating power, but it's set to become a world leader in at least one area: harnessing sea tides to produce energy.

London, 3 March 2003 (RFE/RL) -- If current trends continue, Britain will become a net importer of natural gas by 2006 and oil by 2010. Ten years after that, in 2020, it will have to import three-quarters of its energy needs, mostly from Norway and Russia.

These are the stark conclusions of a recent government "White Paper" on energy.

The implications of such a situation are potentially hazardous for any country, and officials are now looking for ways to reduce this coming dependency.

One obvious solution is to develop alternative and renewable energy resources, such as wind power. Britain at present generates only 3 percent of its total energy from such sources.

It is only appropriate that Britain should be harnessing the wind because the British Isles regularly receive the strongest gales in Europe. Windmill "farms" are becoming a feature of many parts of the country, with some 1,000 turbines already in operation and a further thousand under construction.

Yet, the power of the sea is more promising. Britain, an island nation, has 10,000 kilometers of coastline. Experts say the energy generated by rising and falling tides, if adequately harnessed, alone could cover the entire country's energy needs.

The first pilot tidal energy schemes are already being tested and some look promising. A pilot project in Milford Haven in Wales has already been declared a success. It provides electricity for the local nature conservation area, according to the Welsh Development Agency.

Richard Ayre, the managing director of Tidal Hydraulic Generators Ltd., a firm that helped developed the scheme, tells RFE/RL the project has provided all the starting-point data.

"Basically, so we could come across most of the answers we felt we needed before we went one bigger," Ayre said. "Now, everybody is really quite pleased with how that has gone."

Plant designs for harnessing the tides no longer rely on costly tidal barrages, like in France or Canada, but on turbines that are invisible from the shore, being anchored to the seabed. Tidal Hydraulic Generators has a new and larger pilot scheme in Bristol Channel, between Cardiff and Bristol, also known as the Severn Estuary.

Ayre explains: "We've put a considerably bigger unit into the Bristol Channel. It weighs something like 200 tons. The turbines generally are somewhere between six and 10 meters in diameter. The one [we] are currently looking at, there are five turbines linked into one unit. It will produce, at the peak of the flow in that area, around about one megawatt [of electricity]. We are currently looking in that area at 50 megawatt units, but certainly that is somewhat in the future."

These pilot schemes prove electricity produced by tidal generation is nearly as cheap as that from wind turbines -- and building capital costs are also similar.

Another joint public/private partnership project, based on a different principle and called Stingray, has been assembled in the north of Scotland, at Sullom Voe in the Shetland Islands. The idea is to exploit the enormous tidal forces that create a gigantic sea flow between the Shetland and Orkney Islands.

The Stingray is not a turbine or propeller, but an assembly of huge horizontal wings -- each not unlike a whale's tail fin -- that move up and down in the tidal stream, creating electricity. They are mounted on the seabed, on separate pillars that look like huge oil pumps. Each unit is allegedly capable of producing 90 kilowatts of electricity and there could be thousands of them linked together.

As for Britain's new clean-energy strategy, there is one problem. Clean energy generation schemes are often costlier than burning fossil fuels.

David Porter of the Association of Electricity Producers points that out quite clearly: "Everybody has to have regard to what the customer has to pay, but the message from the government, I think, was that electricity prices will have to rise over a number of years in order to finance these things."

It's still not clear what role nuclear energy will play in Britain's future. Industry experts say phasing out Britain's nuclear plants could create a gap that new forms of energy, including the tidal generation, cannot fill quickly. A spokesman for British Nuclear Fuels, Paul Vallency, tells RFE/RL he believes "renewables" and nuclear energy should co-exist: "Central to the White Paper is a commitment to non- [carbon dioxide] energy sources and, of course, we welcome that, because nuclear is a non- [carbon dioxide] generating source. Clearly, it would be very perverse to have renewable energy, which does not emit [carbon dioxide], being backed by gas, for example, which does. In that way, we see that perhaps nuclear power and renewables are very complimentary and would work well together to give a balanced, diverse, and secure energy mix in the UK."

However Britain chooses to solve its energy problems, tidal generation seems set to have an important role. And should the pilot schemes prove successful, a way of harnessing energy from sea tides would be clear and Britain would show other countries the way forward.