Renewable energy runs into turbulence on the home

Big wind farms are doing well - but poor turbine design means it's not yet feasible for the home user Adam VaughanThursday December 21, 2006The Guardian
Donnacadh McCarthy enjoys sending bills to his electricity company, EDF. It's one of the pleasures he gets from the micro-renewables - solar photovoltaic cells (PV), solar thermal heater and a wood burner - he has installed at his south London home. Mention home wind turbines, however, and you hear a different story.
"I've had my second one for three months now - the first one was vibrating the house too much - and so far it's powered one energy-saving bulb for around three hours a day," he says." It's created a total of 1.6 kilowatts, which isn't even 20p worth of electricity." It's a far cry from the 30 per cent cut in your electricity bill that B&Q, which started selling home wind turbines in October ("only £1,498"), suggests you could save from its model.


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Talking to other early turbine adopters and looking online, it becomes clear that McCarthy's experience isn't unique.
By comparison, large wind farms are flying. So far this year, 540 megawatts of wind power have been installed in the UK, up from last year's 356 and more than double the 240 built in 2004.
On the increase
Manchester City's stadium, meanwhile, has been giving planning permission for an 85-metre turbine able to generate enough power for 1,250 homes. This year, Ecotricity, the green electricity supplier and developer, has 74 megawatts worth of projects at planning stage. If only half are approved - Ecotricity's development arm says it usually has a "near 90%" success rate - they'll more than double the company's capacity of 27 megawatts.
The number of potential sites is also on the increase, thanks to wind turbines built at sea. As George Monbiot points out in his book Heat, wind speeds rise the further out to sea you build, while public opposition drops. A joint DTI-Danish paper puts the matter succinctly: "Offshore renewables also have the potential for greater public acceptability, chiefly because of the likelihood of lower visual impact."
This year, a mere 90 megawatts of offshore power was built in the UK, but the future potential is great. Earlier this week, the government gave the go-ahead to a £1.5bn scheme to build the world's biggest offshore wind farm in the Thames estuary. The scheme could generate 1,000 megawatts - about 1% of the UK's energy requirements. A report from the Department of Trade and Industry last year suggested that offshore wind power could potentially provide 3,213 terawatt hours of power, more than eight times the electricity the UK uses now.
So, if all's finally going right for large-scale wind, what's wrong with its domestic counterpart? One problem is turbulence: in urban areas, buildings, trees and other urban furniture obstruct the wind.
The result is erratic wind speeds, and most home turbines simply aren't designed for that. "Home turbines are definitely not ready for the mainstream," says Dale Vince, founder of Ecotricity. "The current crop suffers from the same fundamental problem of design. They are horizontal-axis machines which work well in open areas but are unsuited to urban areas due to the way they need to rotate to track changing wind directions - called hunting."
Some suggest the problem is the quality of the turbines being sold through utility companies and B&Q. Keith Hall, editor of the Green Building Press, describes them as "not a first generation, but the cheapo generation". He stresses that he has a turbine installed at home and thinks wind is a viable way of generating power, provided companies "don't sell crappy machines".
Friends of the Earth's Nick Rau, by comparison, says a major issue is a lack of independent research comparing the different models on offer. He does, however, point to retailer Better Generation (bettergeneration.co.uk), which sells seven domestic turbines. It also features a graph indicating how much electricity each can generate, although the statistics come from the manufacturer's data, not field tests.
There's one further, crucial piece of information missing for homeowners wanting to "do a Cameron" and fit a turbine: a map of accurate wind speeds. The DTI publishes an online list of average windspeeds, but the most accurate measurement it offers is for 10 metres above ground. Even at that height, windspeeds will be too low to make most home turbines economic.
Wind speeds
In my south London street, the DTI map says average wind speeds are 4.7 metres per second. It's only really above 8 metres per second (17.9mph) that you start to get serious electricity generation of between 100 watts and 500 watts, depending on the turbine. B&Q says: "We advise against installation in poor wind speed locations; we do not install in properties surveyed to be unsuitable."
Proponents of wind power fear a consumer backlash against the technology. "The promises made cannot be kept, they are incredible inflations of what can be achieved, and it is only a matter of time before people that buy them find this out," warns Vince. "The DTI is also concerned about this and has set up a group to look at the issue - they fear the same backlash could affect all micro-generation initiatives."
On this discrepancy between expectations and reality, Monbiot says in his book: "If you wished to destroy people's enthusiasm for renewable energy, it is hard to think of a better method." A bad public experience of wind, it's feared, could even damage confidence in solar PV panels, whose use has been growing steadily in use in recent years.
More positive signs come from the future for large-scale wind turbines, where surveys suggest public opinion has turned. A series of polls by NOP last year showed a growth from May onwards of those in favour of wind farms, peaking at 80 per cent in favour and less than 10 per cent against. Just this month, a YouGov and University of Cambridge poll revealed that two-thirds of respondents "would support wind farms even if situated in their own locality".
Vince believes that wind farms could easily provide 50 per cent of the UK's electricity, a figure roughly backed by the DTI. The price of electricity from wind is also predicted by 10 Downing Street's Performance and Innovation Unit to drop sharply in the next decade, to between just 1.5p and 2.5p per kilowatt hour by 2020 - cheaper than coal. At present, the price per kilowatt hour for wind is bettween 3.7p and 5.4p, while coal costs between 2.5p and 3.2p per kilowatt hour.
Back home, McCarthy hasn't given up on turbines yet. "The jury's out: in a few years time, the technology may change," he hopes. Vince points out that better, second-generation machines should be on sale by next summer.
Tory leader David Cameron hasn't given up home turbines either, saying he still intends to install one on his Notting Hill home. And the public hasn't given up. B&Q reports that its Windsave turbines were the biggest seller by value across its range of 40,000 products in the three weeks following their launch.
For now, those behind home turbines have to hope the machines won't become the energy equivalent of WAP, a technology that massively overstated itself and then failed to deliver.
· Green and efficient land
The 2005 report from the Sustainable Development Commission, Windpower in the UK, shows a theoretical maximum for onshore wind of 1m gigawatt hours, with a practical maximum of 50,000 gigawatt hours.
The report goes on to estimate a practical resource for offshore wind of 100,000 gigawatt hours. That makes for a practical maximum of 150,000, just less than half the 345,243 gigawatt hours the UK consumed last year - the average UK home uses 12.85 kilowatt hours per day. The same report suggests that even 13 gigawatts' worth of wind farms would use just 2,340 hecatres of land - 0.0001% of the UK's 24m hectares.
If large-scale onshore wind reached the practical maximum, the farms would cover 9,000 hectares. "Urban and other use" land, by comparison, comprises 3.3m hectares of the UK.
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