Blown away

In the world's largest offshore wind farm the blades stretch as high as the London Eye, and even in a gentle wind turn at 200mph. Quite something, when you're right underneath, says Patrick Barkham
Patrick Barkham
The Guardian, Thursday 8 January 2009

It was a brilliant sunny day last summer when I first saw the world's largest offshore wind farm on the horizon. I was on the sand dunes at Holkham in north Norfolk when the sky cleared and suddenly, in the far distance, stood dozens of turbines.
This, it turned out, was a brand new wind farm, Lynn and Inner Dowsing, in the shallow waters of the Wash, just off the coast of Lincolnshire. Completed on time and on budget last year, its 54 turbines have a capacity of 194MW, enough to power 130,000 homes.
Britain is now the world's leading generator of offshore wind power, recently overtaking Denmark (other countries have greater onshore capacity). The power generated by offshore wind is still relatively modest but its potential is enormous. Turbines are quadrupling in size, vastly increasing their efficiency and the power they can harvest. And Britain is the windiest country in Europe, its west coast in particular buffeted by punchy, energy-giving winds.
A report for the government by the independent Climate Change Commission recently found that wind generation could be a "major source" of electricity and suggested it could meet as much as 30% of Britain's needs by 2020. Critics, however, have dismissed the figure as unrealistic.
While the first few wind farms were tourist attractions, since then wind power has had a rough time of it. Some people living near turbines complain about noise and sleeplessness. Many conservationists judge them eyesores on the land and a menace to local wildlife, particularly birds. I certainly felt ambivalent about the appearance of this massive wind farm on a horizon I treasured for its restful sense of unlimited space. So I took a boat trip from Grimsby with Centrica, the owners of the farm, to take a closer look.
The North Sea was a dun grey-brown and not until we were virtually on top of them did the turbines loom out of the sea. Then, in one of those miraculous climatic changes that happen at sea, the cloud disappeared: in the sunshine they shone, like spindly white flowers planted in neat rows.
It was only when the boat went directly beneath them that you could appreciate their size. Each turbine was as tall as the London Eye. You could stand inside their delicate (hollow) blades at their root. Not that you would: even in a gentle wind, with the blades turning deceptively slowly, the speed at their tip approached 200 miles an hour.
This farm cost more than £300m and was built in depths of up to 18 metres (59ft) in less than two years. Steel foundation tubes were hammered 25 metres into the chalk below the sandy seabed and the trunk of the turbine was added in two parts. The blades - in this case made in Denmark from balsa wood and fibreglass - have to be phenomenally strong: if the wind speed is 18 metres a second, 100 tonnes of air pass through the blades every second.
Offshore wind technology seems miraculous and slightly bonkers. Why put turbines in the sea? What happens if the sea level rises with climate change? The main reason to place the farms at sea is so they catch more wind. In the boat, at sea level, I couldn't feel much wind; at turbine height there is much more. Part of the attraction is also the assumption that offshore farms attract less criticism and less Nimbyism.
"I suspect people thought there would be fewer stakeholders offshore and it would be easier, but there are actually more," says Alan Thompson, head of renewables at Centrica. These include not only coastal home-owners and local councils, but fishermen, environmentalists, maritime authorities, coastguards, sailing clubs and, most problematically around East Anglia, the Ministry of Defence, which has complained that turbines interfere with air defence radar.
Fishermen made strong protests against Lynn and Inner Dowsing. On the day I visited, however, there were eight mussel boats fishing between the two groups of turbines. Research from Denmark suggests that the artificial reefs created by the farms may actually provide useful new habitat for shellfish.
Another reservation about offshore power is a claim that farms are proving much more expensive to maintain than expected. Centrica's maintenance costs are fixed for the first five years, thanks to government investment; it says it is too early to judge if maintenance costs will prove prohibitive. Maintenance is, at least, creating jobs - boats are staffed by former fishermen - and engineers are routinely sent to Lynn and Inner Dowsing from Grimsby's port.
Wind power, sceptics also claim, is intermittent and unreliable. According to Thompson, these turbines generate power 85% of the time. Each turbine produces about 40% of its potential capacity over a year, although in the windier north-west of the country this can rise to above 50%.
And sea-level rise? These turbines are designed to withstand rises of just 250mm but are predicted to have a 20-year lifespan, such is the strain of constantly moving parts in strong winds. It doesn't sound long, but power companies expect to "repower" the farms with updated turbine technology in a couple of decades. Having built foundations and laid power cables back to the land, it makes sense to keep using them.
Lynn and Inner Dowsing will not hold its world title for long because turbine capacity is increasing so quickly. While the 20 turbines at Centrica's Glens of Foudland onshore farm, which opened in 2005, each produce 1.3MW of power, its proposed second offshore Lincolnshire farm, recently given planning approval, could feature 5MW machines, with the whole plant producing 250MW in total.
The chill wind of recession, however, is slowing down the offshore revolution. Even though it now has consent for the second Lincolnshire farm, Centrica admits it is currently calculating whether it can proceed in such difficult economic conditions. Many energy companies complain that the UK's renewable energy subsidies are not generous enough: Shell, for instance, last year pulled out of the proposed London Array wind farm. The government's target is for 33GW of offshore wind by 2020; so far it has taken seven years to get consent for 3GW of offshore power.
I will look on the turbines more affectionately when I am next on Holkham beach, but our willingness to embrace wind power may still be moving too slowly to solve our looming energy crisis.