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3 May 2007

Alternative energy

Winds of change?

MOST SCIENTISTS agree that climate change caused by centuries of burning fossil fuel is a serious threat to the future of the planet. The world's governments, however, are failing to meet even the moderate curbs on emissions of carbon dioxide they have agreed. In Britain, carbon emissions are now higher than when New Labour took office in 1997, and the government is unlikely to meet its 2010 target. As part of our series on alternatives to fossil fuel, PETE DICKENSON looks at wind power.

GEORGE BUSH thinks that the answer to global warming is to put giant mirrors into space to reflect back the sun's rays in order to reduce the earth's temperature. Tony Blair seemed to agree with him that new technology is the answer, according to remarks to journalists when leaving a plane after a holiday in Florida earlier this year.

Certainly, more research is needed on solutions. But Bush's highly speculative scheme - that he has no intention of putting money into - is just a smokescreen to divert attention from existing viable sustainable technologies, such as wind, solar, tidal and wave power that could be implemented on a mass scale now. These methods do not make the greenhouse gases produced from burning fossil fuels such as coal, oil and gas that cause global warming.

Britain is one of the world's windiest countries so an obvious choice is to develop wind turbines to meet our energy needs. But the government only plans to increase wind power energy generation to 15% of total electricity needs by 2015, which is totally inadequate to tackle climate change. Ernst and Young, a consultancy company, recently found that Britain has the potential to produce 1,000 terawatt hours of wind-generated electricity per year, which is equivalent to several times UK annual consumption.

Wind turbines work by using the wind's power to produce electricity. The wind rotates blades in the turbine that drives a generator, producing the power that is then fed into the electricity grid.

A typical on-shore wind turbine is about 100 metres (about 300ft) tall, with blades 30-40 m long, and produces 2 megawatts (MW) of power, a small output compared to a conventional power station, so tens of thousands would be needed. Turbine capacity, though, is increasing all the time as new designs come on-stream.

5MW machines already exist, so the total number required could drop rapidly. Three big wind farms, North Hoyle, off the North Wales coast, Scroby Sands near Great Yarmouth and Kentish Flats off Whitstable, already produce electricity for the national grid and ten more sites are due to start up in the near future.

Off-shore farms

There are debates such as whether to develop on-shore or off-shore wind farms and whether micro-generation, e.g. each house having a wind-turbine on the roof, is a desirable option. The main benefit of on-shore development is low cost, but producing off-shore electricity is inherently more technically efficient. Wind speeds off-shore are much higher and power generated increases as a cube of wind speed, i.e. if the wind blows twice as fast, eight times as much energy is produced.

Also, turbines in a wind farm need to be separated, so one machine does not take wind from another. This is not usually entirely possible in on-shore locations because of requirements to connect to the grid and because of environmental concerns that wind farms are an eyesore whose size needs to be minimised.

The problem with micro-generation is that it is less efficient than grouping turbines in wind farms because the economies of scale are lost, in particular the costs of connecting to a national grid are much higher.

If such turbines are operated independently and not connected to a grid where they can be controlled centrally, the problems of intermittent operation due to variable wind speeds, i.e. the machine doesn't work if there is no wind, are much worse. (The reasons for this are discussed below).

Other drawbacks are that many people would think it ugly to have thousands of machines installed on roof-tops and there is the potential problem of noise emitted by the turbines.

The main technical objection, of course, to wind power is that when the wind doesn't blow no electricity can be produced. However, studies of long-term British weather patterns show that only very rarely are there still conditions over the whole country, so if turbines are positioned all round the coastline and connected to a national grid, the problem can be minimised.

This would be done by moving electricity generated where the wind is still blowing, through the grid, to the wind-deficient areas. Also, the turbine itself can rotate to catch the wind and produce power even in relatively quiet conditions.

Supplementary measures

Despite these technical measures to improve the availability of wind-generated electricity, there will always be times when other sources of energy will be needed to meet demand, particularly peak demand on a cold day. In the short-term it would be possible to use gas-fired power stations to generate the extra power to meet the peak requirements, and still reduce greenhouse gas output overall by the approximately 70% required for sustainability.

However, in the medium term it will be necessary to move to 90% or 95% cuts in greenhouse gas emissions for sustainability as energy use increases in industrially developing countries, increasing the pressures on the environment even more.

This will mean developing other existing environmentally friendly sources of electricity, such as wave and tidal power and possibly looking at new technologies such as carbon capture, where greenhouse gases produced by fossil fuel burning are captured and stored under the sea. Even if there was no need to develop additional sustainable energy sources to meet peak demands, it would still be unwise to develop just one technology because of the uncertainty resulting from global warming itself.

Patterns of ocean currents and prevailing winds in the northern hemisphere could change due to arctic ice melting, then moving south and meeting warmer water in the Atlantic. This could disrupt the Gulf Stream, leading to dramatic climate changes in north-west Europe, including it becoming much less windy.

In these circumstances, it would be necessary to develop some other sustainable energy sources that are unlikely to be as affected by changes in ocean currents and prevailing winds.

Planning needed

A plan needs to be drawn up using all the available information to establish long-term priorities for sustainable development. Wind power does not provide all the answers to global warming, but it could go a significant way to improving the situation, and the technology exists now and is tried and tested. Its widespread use will also generate tens of thousands of new jobs.

So why is more not being done to expand its use, beyond the totally inadequate targets already set (which may not be reached, just as Blair's targets for reducing greenhouse gases have been abandoned)? The reason is that calculations by the government and capitalists revolve around the short-term costs of the different energy alternatives, not the needs of the environment or of people.

Until the recent huge rises in gas prices in Britain, the cost of generating a unit of electricity by wind power was three times higher than with gas, but now there is not much difference. This price does not include the long-term costs to the planet of burning fossil fuels, it is only the current market rate. If the long-term cost was calculated, sustainables would be much cheaper.

So can we expect market forces to take over now and expand sustainable energy technologies since the costs are the same? This, unfortunately, is very unlikely to happen because if the price of gas remains high, the energy companies will look at expanding coal-burning again, which is now much cheaper.

Profit will always be the determining factor for big business, even if the short-term savings they stand to make by continuing to use fossil fuels are relatively small. The recent Stern report pointed out that moving to sustainable energy would only cost 1% of GNP per year extra over a fifty-year period. Yet even this small burden is too much to bear for the multinationals, who will fight tooth and nail to maintain their profits.

Global warming can only be beaten by casting aside this market madness and replacing it with democratic planning for a sustainable future.