While the Campaign to Protect Rural England (CPRE) is opposed to the construction of wind turbines because of their visual impact on the countryside, we also believe they do not reduce CO2 production as they are not reliable and are therefore inefficient.
On average, wind turbines generate around 25 per cent of their installed capacity, meaning the output of a large turbine with a maximum capacity of 2MW will be 0.5 MW at best. When there is no wind, turbines use power from the National Grid to turn the blades to prevent damage to the bearings.
The biggest problem with using such sources of power is that it makes the National Grid unstable. Electricity has to be used as it is generated.
The National Grid’s job is to keep supply and demand in balance. If that balance is not achieved, the lights go out. Keeping the grid in balance is comparatively straightforward when the power sources – oil, gas, coal, nuclear – produce a stable output. The output of a wind turbine is unpredictable, unstable – and can fall to zero very quickly.
Unfortunately, demand for electricity is not linked to when the wind is blowing. It is not unusual for prolonged cold snaps, like last winter, to occur where there is no wind at all. This creates issues for the grid which, in order to balance supply and demand, has to be able to ratchet up conventional generation to cover for the lack of wind energy at any given time. If it does not, there are power cuts.
The grid was designed to operate with a 20 per cent contingency margin – to protect against a power station going down. Up to this level, it is able to cope with fluctuations of power supply, such as those produced by wind turbines.
As the number of wind turbines increase beyond this contingency level, the grid must use additional conventional back-up to cover demand when there is no wind. This means the building of more conventional power stations. We are already at this point.
However, it is not as simple as building a new power station and keeping it switched off until it is needed. The turbines have to be kept pre-heated and on standby. This is a very inefficient way of operating a power station and is a big factor in the negation of the CO2 savings claimed by the wind power industry and the wind lobby.
Denmark, which pioneered commercial wind generation, has not closed a single conventional power station.
In addition, if wind power is supplying more power to the grid than it can at that time cope with, the energy companies are paid a great deal of money over and above the value of the energy they would otherwise have supplied to the grid to turn them off. In 2010, the figure was more than £1-billion.
We all agree we need to reduce reliance upon fossil fuels. But to concentrate the lion’s share of resources to prolonging the life of this unviable technology at the expense of other potentially more reliable sources is not in my view a sensible or viable way forward.
” When there is no wind, turbines use power from the National Grid to turn the blades to prevent damage to the bearings
Copyright 2012 Scunthorpe Telegraph
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