| Environment |
Breaking With Tradition |
The Guardian
18 February 2004 |
Using waves to generate electricity has long been dismissed as uneconomical.
But Paul Brown and John Vidal report on a plethora of new plans to harness
the power of seas, rivers and tides....
In the early 1980s, wave power was going to be the bright new future for
energy, but in a government evaluation of how much the electricity would
cost to produce, someone moved a decimal point -- and made it 10 times more
expensive.
Years later, when the "mistake" was discovered, the government had already
abandoned wave research, while the Department of Trade and Industry (DTI)
continued to pour money into design and development of the nuclear industry.
If the decimal point had not been moved, the history of renewable
development in Britain might have been completely different.
But, although it has taken 20 years, wave power has made a comeback. It has
been joined by other tide-driven renewables to make the untapped power of
the sea one of the greatest prospects for jobs and a new industrial base for
coastal Britain.
The suspicion of the DTI and its attitude to renewables was dispelled last
week with the enthusiasm of Stephen Timms, the energy minister, at a
conference in Bristol on wave and tidal energy. The government is launching
a £200,000 campaign to encourage planners and industry to get positive about
investing in renewables. The DTI is also putting money into what is called a
wave hub, an undersea device into which manufacturers of floating
electricity generators using wave power can plug their machines.
The £500,000 cost is in effect a subsidy. By providing a feed to the
national grid that developers can rent, they are avoiding the crippling
capital cost of doing it themselves. The developers can recoup the rent by
selling electricity to the national grid, while at the same time testing in
real waves whether their designs will stand up to the rigours of survival at
sea.
Instead of one of two possible designs of utilising sea power that were
being tested in the 1980s, there are now dozens. There are those on the sea
shore, using the power of the waves as they reach the end of their journey,
but larger scale possibilities come from machines anchored out to sea. Once
a device is proved to work effectively, hundreds of the same could be
harnessed together, providing wave farms.
Some believe that attaching floating wind turbines would further increase
the efficiency. Stephen Tindale, executive director of Greenpeace, says:
"There is the same buzz around these technologies as there was about
offshore wind three or four years ago."
Eight developers have been chosen to take part in a scheme to evaluate wave
energy. The government-funded Carbon Trust is putting £2.5m into a marine
energy challenge, aimed for completion by the end of the financial year
2004/05.
Of the successful bidders, four device developers are from overseas - two
from the US, one from Denmark and the other from the Netherlands. The
challenge is designed to attract foreign investment into the West Country
and make the area a world leader for the technology.
They involve machines that use the rise and fall of the waves to push air
and water through turbines.
So far, it is impossible to predict how much electricity from a fully
developed wave industry would cost, but the government's estimates are
around 4p per unit, compared with 7.5p that consumers currently pay through
their meter, and probably less than new nuclear build. Wave power at this
price could provide 10% of Britain's energy needs, but it could be more; no
one will really know until the work is done.
According to Matthew Spencer, chief executive of South West Renewable
Energy, which organised the Bristol conference, a two-metre wave has roughly
the same power as a small saloon car engine. The problem, he admits, is
getting that power from nine miles out and into the grid.
But wave power is only part of the story. Underwater tidal currents, which
have enormous power, are also proving to have exciting potential in the West
Country - and in lots of other places where tides squeeze between islands,
from the Shetlands to the Channel Islands.
The first in the water is being run by Marine Current Turbines in the
Bristol Channel at Lynmouth. It is like an underwater wind turbine and began
operating last summer. Initial results are promising. A full-scale test
project will be installed between now and 2005, using bigger machines that
each generate a rating of 750kW to 1.2MW, which will be grid connected. They
are too deep underwater to interfere with shipping and, unlike wind farms,
should not generate environmental controversy. In addition, there is a
variety of schemes to take advantage of the West Country's remarkable rise
and fall in tides.
The advantage of tides over wind is that the rise and fall, and the undersea
currents they generate, are predictable years in advance, enabling producers
to know how much electricity they can expect. It solves one of the great
criticisms of renewables - that they provide only an intermittent service.
Not that this is any longer a valid argument, as renewables engineer Allan
Jones, from Woking council, Sur rey, has demonstrated. By harnessing
together solar, combined heat and power, and gas generation, he has ensured
security of supply by adjusting supply to demand as it fluctuates. He
advocates that any "spare" electricity being generated by renewables should
be used to manufacture hydrogen, which can be used to power fuel cells,
either to run buses or create more electricity the following day.
Meanwhile, the potential of the river Severn to become one of Britain's
biggest providers of renewable electricity, and to spearhead regeneration in
Wales especially, is also being explored. The river has a 40-foot tidal
range, and a dam across it has been proposed for more than 25 years.
Although studies concluded in 1987 that it could generate 12% of Britain's
electricity, it was shelved because of the enormous costs and the inevitable
environmental outcry.
Now a new study suggests that there is a far cheaper and less damaging way
to generate renewable power from the river. The idea is known as "tidal
lagoons" - large, rock-walled impoundments that trap water and release it
through turbines. According to the report by Friends of the Earth Cymru,
based on industry data, an area equivalent to 11 miles by 11 miles could
provide 6% of Britain's electricity demand (2.75 GW) - the equivalent of
three or four nuclear power stations. Moreover, it would impound an area 40%
smaller than the barrage, cost far less and would not impede shipping or
damage the ecologically sensitive inter-tidal areas of the estuary.
Developers at Tidal Electric, involved in the concept of tidal lagoons, have
met Timms, who is positive about the idea. A team of engineers lead by WS
Atkins, Britain's largest engineering firm, and ABP mer, the research arm of
Associated British Ports, is designing a 30MW offshore tidal power project
for Swansea Bay, in the western part of the Severn estuary. The team will
report soon on the feasibility of this specific project, including output,
construction techniques, and environmental issues. If a scheme is built in
Swansea Bay it would be the world's first and applicable in many places,
including Liverpool bay, the Thames estuary and Morecambe bay.
|
