The UK plans to become a world leader in wind technology through the development of offshore resources. Are these ambitious plans realistic, asks Siân Green.
The UK government has announced plans for a major expansion in offshore wind energy that could see up to 1500 turbines with a combined capacity of 6 GW being constructed by 2010. The plans call for up to £6bn of investment in offshore projects and represent the largest ever expansion of renewable energy in the country.
Developers have been invited to bid for projects in three strategic areas around the UK coast. The government will announce the results of the bidding in November, and the first units could be operational by 2008.
The plans represent a ten-fold increase in wind capacity in the UK. If all the projects are successfully developed, wind energy will account for some five per cent of total UK electricity supplies by 2010, according to the British Wind Energy Association (BWEA). The projects will also account for half of the government’s target of obtaining ten per cent of all electricity supplies from renewable sources by 2010.
The UK has the best wind energy resources in Europe, including an estimated 33 per cent of Europe’s potential offshore wind resource. Yet it lies near the bottom of the European league table of wind power generation. The UK has an installed wind capacity of 552 MW, compared with 12 001 MW in Germany, 4830 MW in Spain and 2880 MW in Denmark.
The government believes that these latest plans for offshore development will change this, making the UK a world leader in offshore wind. It foresees a major expansion in manufacturing, installation and maintenance in the UK to support this new industry.
These plans follow on from a round of offshore development announced in late 2001, which could see 1.5 GW of wind farms being developed by 2006. Two of these projects – North Hoyle and Scroby Sands – are already under construction. Altogether, wind power capacity in the UK could reach 8.8 GW by 2010.
The wind power industry in Europe has seen a shift towards offshore development in recent years for a number of reasons. Wind speeds are higher offshore than onshore, and turbulence is generally lower. Siting wind turbines at sea instead of on land also eliminates challenges such as visual impact. Nevertheless, developing offshore resources also presents challenges.
Engineering consultants Babtie Group has welcomed the plans but has pointed out that a number of issues need to be resolved if these projects are to be successful. One of the challenges is a lack of experience in building and operating wind farms offshore. North Hoyle and Scroby Sands are the first major offshore wind farms to be developed in the UK, and while larger farms have been developed in other parts of Europe, operating experience is relatively limited.
“One of the big issues is the risk of operating this equipment offshore over a long period of time,” says Graham Boothman, divisional director at Babtie Group. “Maintenance costs are only estimated at the moment because they have not run the wind turbine generators for long periods in such hostile marine environments.”
What is known, however, is that operation and maintenance of wind turbines is more expensive offshore than onshore. Wind turbines require regular planned maintenance. For offshore sites, this must be done by boat and helicopter, and is weather-dependent. “These costs must be factored in,” notes Boothman. “There is no doubt that we’ll be able to build them, but the devil is in the detail of the whole life costs over a 25-year cycle.”
Another key issue facing the developers of these offshore facilities is connecting the wind farms to the national grid. Parts of the grid will require strengthening and upgrading in order to cope with the additional generation, and to transport the power to demand areas. “Our system has primarily been design for top-down flows of power,” explains Clive Poole, technical director at Babtie Group. “When you start injecting energy into that system at lower voltages, not only do you have to put assets into place to make the physical connection, but you also have to reinforce the network to allow for the additional power coming in.”
National Grid and Scottish Power have estimated that it could cost up to £1.5bn to strengthen the UK’s networks to accommodate these wind projects. These costs, and the costs of developing the projects, will ultimately be met by consumers through higher electricity bills. Few are willing to put a number on the increase, although the government noted in its recent energy White Paper that implementing measures to achieve a low carbon economy could add 5-15 per cent to domestic electricity tariffs. BWEA notes that the first offshore wind turbines in the UK are generating electricity at around £0.05/kWh.
The growing market for offshore wind farms has encouraged technology development, and in particular the development of large-scale wind turbines such as GE’s 3.6 MW machine. It is these large machines that the government envisions being installed around the coast.
“The government is making the assumption that the new wind turbines that are being planned for use in these projects – and are up to 5 MW each – are proven [technology],” says Boothman. “Machines of this size are still being developed and are not proven technology. The largest machines of good reference at the moment are 2 MW.”
There is now doubt that the development of large offshore wind farms will bring economies of scale and this will be of great benefit to the industry in the long run. But with so many short term uncertainties, how easy will it be for developers to get financing for large, offshore projects?
“There will be less enthusiasm from banks to put up loan capital for offshore projects compared to onshore projects because onshore is obviously lower risk,” says Boothman. “It’s very important that these first few wind farms get built quickly and on time, and show operational reliability.”