Wind power is one of the fastest growing energy technologies in the world. Since the industry took off in Denmark the early 1980s, it has created tens of thousands of new jobs globally and the installed global capacity has passed 40,000 megawatts (MW), generating enough electricity to power over 10 million homes.
In Australia wind power capacity is over 250 MW and the industry is growing rapidly, at least until 2007 when the tiny Mandatory Renewable Energy Target is expected to be achieved. Yet Australia’s wind energy potential is large. The scenario study, A Clean Energy Future for Australia (pdf file 1.24MB), proposes that 20 per cent of Australia’s electricity could be generated from wind power by 2040, the same percentage that was achieved in Denmark in 2003.
Wind turbines are best sited in prominent places such as on ridges, hill-tops and near the coast, where they can catch the wind. Although the numbers of people, identified in public surveys as being concerned about the visual effect of wind turbines is tiny, anti-wind groups are even being set up in areas of degraded farmland that are almost treeless and often extensively eroded. Anti-wind campaigners are succeeding in creating anxieties in rural communities by claiming that wind has major environmental impacts and technical limitations.
Some of these campaigners pose as environmentalists, while actually being unwilling to say or do anything of substance about the greenhouse effect, one of the most serious of all global environmental problems.
This article critically examines the environmental and technical anti-wind arguments that are being disseminated and the politics of opposition to wind power. In doing so I take the position that every person is entitled to their own aesthetic judgement about the visual effect on the landscape, but they are not entitled to bolster their subjective opinions by disseminating exaggerated and in some cases entirely false notions about the environmental impacts and technical performance of wind power.
Alleged environmental impacts
Opponents claim falsely that wind turbines are very noisy, a major killer of birds and a threat to biodiversity in general. In reality, during operation modern wind turbines reduce the biodiversity damage done by fossil fuels and emit essentially no chemical pollution. Their only physical emission, noise, is inaudible beyond several hundred metres, except under very rare topographical conditions.
The energy required to build a wind turbine is generated in 3-5 months of operation, so, with a 20-year lifetime, a wind turbine generates 48-80 times the energy required to construct and install it. Wind turbines are highly efficient in capturing renewable energy, since blades occupying only about 5 per cent of the swept-out area can in practice extract 30-40 per cent of the wind energy flowing through that area. As a result the material inputs to a wind farm are modest and indeed are comparable with those of an equivalent thermal power station without fuel.
Of the thousands of existing wind farm sites around the world, there are really only two (Altamont Pass in California and Tarifa (pdf file 24.9KB) in Spain) where bird casualties have been a significant problem and only two (both in West Virginia, USA) where bat casualties are a problem. Australian studies on the impacts of wind farms on birds show that there is an even lower level of impact here than was predicted on the basis of northern hemisphere experience. This may be because Australia does not experience the same concentrations of migrating birds found in some parts of Europe and the USA.
In comparison, on a single foggy night about 3,000 birds were killed when they collided with the chimneys of a fossil-fuelled power station in Florida, USA. The main hazards to birds are lattice-type communication towers, office buildings and cats.
To assess the biodiversity impacts of coal versus wind power, the global impacts, as well as the local impacts, must be taken into account. Global climate change resulting from the human-induced greenhouse effect is predicted to wipe out many species of animals and plants. In Australia the biggest single source of greenhouse gas emissions is coal-fired power stations. By substituting for coal and other fossil-fuel power stations, wind power reduces carbon dioxide emissions and therefore saves global biodiversity.
To reduce local biodiversity impacts of wind farms, planning guidelines for the siting of wind developments are being put into place by Federal, State and Local Governments. Proposed wind developments have to receive planning approval under the Commonwealth’s Environment Protection and Biodiversity Conservation Act and also under any local regulator. This addresses the protection of wetlands and other specific areas of environmental importance and sensitivity.
Wind farms are highly compatible with agricultural and pastoral land. Their towers and access roads occupy very little land, only about 0.25-0.75 hectares per megawatt of installed capacity, leaving the rest for sheep, cattle, wheat, etc. For the same amount of electricity generated, coal-fired power stations and their mines (even underground) have much bigger impacts on land.
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