Sir – I was disturbed by the article about the possible closure of Wallingford bridge to all but electric vehicles (Herald, December 16).

Perhaps the laws of physics have changed since I was at school in the 1950s. I was taught that every change in the state of energy (e.g. mechanical to electrical) results in a large loss, usually over 50 per cent.

I read recently that the efficiency of a traditional power station is in the region of 30-40 per cent, and modern ones are not much better.

The lost energy is dispersed as heat in the atmosphere, rivers etc.

At the same time, vast amounts of carbon dioxide are produced. Users of electric vehicles charge their batteries from the mains supply.

With the additional losses incurred between the power station and the power point, this implies the efficiency of an electric vehicle must be no more than about 20 per cent.

Thus it seems to me that, as regards to saving the planet, the promotion of electricity is wrong.

But perhaps the situation can be improved by covering half the world with solar panels and wind farms!

In the long run, with present-day technology we cannot have “clean” air in our towns and cities and simultaneously prevent the world overheating – unless my physics teacher was wrong!

Harry Fell