Letter: Physical flaw

Further to the debate over wind farms, I'm afraid the notion that if the prevailing wind is within the operating limits of a wind turbine its generator's power will be used by the grid thereby reducing the amount of fuel conventional power stations need to burn is a misunderstanding of basic physics.

When three phase generators are paralleled, their output voltage and frequencies are electrically locked together, the only factor that governs the amount of power (watts) each delivers at any instant in time is its input torque (turning force) relative to that of all the generators.

This is known as "highest wins" and is why the most powerful stations (mainly nuclear) with a vast amount of constant torque provide their full power (to supply our constant demand known as base load) whereas anything we demand between base load and peak is supplied by more flexible smaller stations, which modulate their steam to maintain a constant frequency as demand varies.

For a wind-driven generator to supply power, its input torque must be greater than that being supplied to the generator supplying the least amount of power at that instant, and as wind gusts those occasions are random and over which we have no control.

BRIAN CHRISTLEY

Bryn Gwyn

Abergele, Conwy