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But don't wind turbines help reduce carbon dioxide (CO2) emissions ?

Unfortunately not. In spite of what the power generating companies and the wind farm developers say, wind turbines have very little effect on the total emission of CO2 from fossil fuel power stations.

The reason for this is simple.

Energy output from wind varies from zero to 87% of their rated capacity, depending on the wind. If the wind speed is less than about 5 metres per second (11 mph), no electricity is generated; if the wind speed is greater than about 25 metres per second (56 mph), turbines are shut down for safety reasons.

On average, wind turbines in the UK generate about 23% of their rated capacity.

All power plants need a certain amount of backup to cover down times, but wind power is unique in that the down times are intermittent and unpredictable. The backup for wind power must be running continuously, ready to go on stream immediately in response to changing weather conditions. The crucial point here is that this "spinning reserve" is burning fossil fuels and emitting CO2 even when not producing electricity.

To date it has been assumed as self evident that wind generated electricity will save carbon. There is very little evidence that this is the case and indeed mounting evidence that wind generated power is not carbon friendly. Current available figures bring us to conclude that during its lifetime one 3MW turbine will "save" 6,356 tonnes of carbon and "cost" somewhere between 27,213 and 40,773 tonnes of carbon. Dr. Sarah Myhill, of Llangunllo, Powys, has studied the problem. Click here to download her research paper.