RALPH Marshall (‘Heading to catastrophe’, Letters, July 27) identifies some problems with wind energy, stemming from variable wind speeds.

Some of these problems are real. He exaggerates their scale, and doesn’t acknowledge how they can be addressed. But his concerns are legitimate ones.

What is not legitimate is his assertion that wind farms increase CO2 emissions. There is no evidence whatsoever for this. I imagine the source for this assertion is Poole and Christchurch Bays Association’s submission to the Navitus Bay Planning Examination.

This grossly exaggerated the inefficiencies in gas turbine backup which are needed to balance the variability of wind output.

The PCBA’s distorted account ignored the fact that modern Combined Cycle Gas Turbines, like the one at Marchwood that would provide most of the backup for Navitus Bay, are designed to vary their output with minimal loss of efficiency.

It also ignored the potential of innovations in energy storage to provide lower carbon sources of backup.

If Ralph Marshall includes himself amongst those concerned that we may be “heading to catastrophe”, he should look at authoritative evidence, from bodies such as the Centre for Energy Policy and Technology at Imperial College, and acknowledge the important role that wind energy, as part of a balanced electricity supply system, can play in decarbonising electricity supply.

ALAN NEALE Poole