Britain | Renewable energy

Perfect storms

The use of offshore wind power is growing, but costs must come down

|BARROW-IN-FURNESS

AS A sharp winter wind whips up the Irish Sea off the coast of Cumbria in north-west England, a group of engineers—snug in their onshore control room—gaze contentedly at their screens. Almost all of the 108 giant offshore wind turbines that make up the West of Duddon Sands wind farm are flashing green, indicating that they are operating at full capacity.

With a following wind, each turbine at this 26-square-mile (67-square-kilometre) facility can contribute as much as 3.5 megawatts (MW) of electricity to the national grid, enough to provide power for more than 2,500 households per year. That adds up to around 389MW for the whole farm at full capacity, making it one of the biggest offshore wind farms in Britain, though the nation’s largest coal-fired plant can produce ten times that much energy.

That is only a fraction of what the power companies want to build in future. Britain already has the most offshore wind turbines of any country in the world. But Scottish Power, for instance, which (together with the Danish company DONG Energy) built West of Duddon Sands, is now ready to begin work on a much larger project: East Anglia ONE, off the coast of Suffolk in eastern England. This will cover around 115 square miles and have about 200 turbines. There are similar plans for large wind farms along several stretches of Britain’s coastline.

Yet for all its recent advances, offshore wind remains very expensive. The West of Duddon Sands farm cost a whopping £1.6 billion ($2.5 billion) to build, much more than its equivalent would have cost onshore. Scottish Power and DONG had to build an entirely new £50m harbour across the Irish Sea at Belfast, just to load up the turbine parts for the journey. Then there were the specially designed maintenance vessels, undersea cables and more. As a result of these kinds of costs, offshore wind energy has been heavily subsidised by a government anxious to meet Britain’s target of obtaining 15% of its energy consumption from renewable sources by 2020. But the debt-laden government is also increasingly anxious to cut its expenditure and, with it, the subsidies. The future of the offshore wind industry thus depends heavily on whether the costs of the energy it produces can come down, and how fast.

At the moment, the cheaper, longer established onshore wind farms still generate more energy, and there are plenty more being planned. But the balance is shifting, as the output of the much bigger offshore wind farms soars (see chart). In 2002, Britain boasted just two offshore wind turbines. Now it has 1,183, with most of the growth occurring since 2008.

There are several reasons for the rush to offshore wind. One is the increasing difficulty in finding sites of sufficient size to build larger, and therefore more cost effective, wind farms onshore. Politically, they are more controversial, as people object to their size and the noise of their blades. On top of that, other offshore technologies have disappointed, explains Keith Anderson, head of Scottish Power. Expectations for tidal and wave power were high but have not delivered.

By contrast, it has been relatively simple to take the established technology of onshore wind farms out to sea, where engineers face few aesthetic or environmental restraints on the size of the individual turbines. There are currently plans for behemoths with a rotor diameter of 160 metres (525 feet), generating 10MW each (the blades in Cumbria sweep 120 metres).

Such economies of scale should also help to lower costs, as the industry is keen to point out. The government itself has helpfully outlined ways that it should do so, and manufacturers want to look obliging. Yet the industry says that it should not bear the burden of lowering those costs alone, arguing that it still needs the security of more government money after 2020 to scale up. “The bigger the projects we can build,” says one engineer, “The faster the costs will come down.” Expect some icy gusts of disagreement over that in the next few years.

This article appeared in the Britain section of the print edition under the headline "Perfect storms"

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