Building large-scale wind farms on peat bogs could actually increase the emission of greenhouse gases, according to scientists.
Britain’s peatland holds 3.2 trillion tonnes of carbon trapped in the soil, but will easily leach harmful gases if damaged.
More than half of the wind farms planned for Scotland are intended for areas of peatland, which are commonly found in rolling upland areas perfectly suited for giant turbines.
Peatland makes up just over 10 per cent of England, 20 per cent of Wales and 65 per cent of Scotland.
Researchers at the University of Aberdeen have devised a method to calculate the ‘carbon payback’ time for wind farms on peat soil. It is currently used by the wind farm industry to assess the CO2 impact of their developments.
As turbines are mostly located in remote areas, they require miles of new roads to service them, drying out or destroying the peat below.
Peat only retains carbon when it is moist, so any large-scale damage would result in huge amounts of carbon being lost to the atmosphere, which scientists say contributes to global warming.
They concluded that building giant turbines on pristine peat should never be allowed, as the damage would outweigh any green benefits.
The researchers found wind farms can still be built on degraded bogs, but ‘good management’ would be crucial if carbon savings are to be achieved.
The new director-general of the National Trust yesterday came to the defence of wind farms, describing turbines as ‘beautiful’ and arguing that future generations will look at them with fondness.
In an interview, Dame Helen Ghosh said: ‘Wind turbines in the right place are fine. We object to wind turbines where they are a blot on our historic landscape.’ She added: ‘I think they can look graceful, and this goes back to thinking in centuries. If you think back to what the railways looked like to the 19th century mind…I think we have to have our minds open to how the wind turbine will appear to us in 100 years.’
There are currently more than 3,300 onshore wind turbines in Britain, with 2,600 more approved or being built. The industry is also seeking planning permission for a further 2,850.
In a letter to the journal Nature, the Aberdeen research team led by Dr Jo Smith wrote: ‘We contend that wind farms on peatlands will probably not reduce emissions, unlike those on mineral soils.’ With carbon emissions for power production set to drop in the future, the scientists added: ‘Peatland sites would be less likely to generate a reduction in carbon emissions, even with careful management.
Unless the volume of peat excavated can be significantly reduced relative to energy output, we suggest that construction of wind farms on non-degraded peats should always be avoided.’
The wind industry insists that it increasingly builds ‘floating roads’ which do not disturb the peat.
But wildlife conservationist and peat expert, Richard Lindsay of the University of East London, said these roads inevitably sink and cause long-lasting damage.
It is estimated that half of all new wind farms are planned for areas that contain peat.
‘Peatland is not suitable for wind farms for a whole host of environmental reasons, not just carbon loss,’ said Mr Lindsay. ‘But even if we are just looking at greenhouse gas emissions, in the long run, the damage done to a peat bog by building roads and infrastructure will outweigh the benefit of building a wind farm.
‘The tragic irony is that the exact places were blanket bogs develop are also perfect for wind farms in terms of the conditions and being away from residential areas.’
Helen McDade, from the John Muir Trust, which campaigns to protect wild land, said: ‘Left in or restored to good condition, [peatland] lock in harmful greenhouse gas emissions. It therefore makes no sense to site major industrial wind developments that are supposed to be helping achieve CO2 reduction targets, on such sites if they damage the peat and release significant amounts of carbon dioxide into the atmosphere.’
Jennifer Webber, a spokesman for RenewableUK, which represents the wind farm industry, said: ‘Currently wind farm developers undergo an environmental impact assessment ahead of each development, so the benefits and costs of a scheme in total can be rigorously assessed.’