Gordon James implies that the Princes Gate Spring Water wind turbine will play a part in “saving our planet” but Geoffrey Sinclair points out that its trivial contribution to reducing CO2 emission is less than a thousandth of the saving by the proposed Atlantic Array (Wind turbine plans blow up new storm, 18 January).

Mr Sinclair is nearer to hitting the nail on the head but both these statements could only be true if wind power itself mitigates substantial CO2 emission. This is what E.ON UK has to say on the matter: - “It could take 50 gigawatts of renewable electricity generation to meet the EU target. But it would require up to 90% of this amount as backup from coal and gas plants to ensure supply when intermittent renewable supplies were not available. That would push Britain’s installed thermal power base from the existing 76 gigawatts to 120 gigawatts” (The Guardian, 4 June 2008).

The extra fuel used in keeping these extra power stations ready to generate makes a nonsense of any claim for substantial mitigation of CO2 production by any number of wind turbines.

Dr JOHN ETHERINGTON, Llanhowell, Pembrokeshire.