What is renewable energy?

The sun draws on its non-renewable source of hydrogen which at some point will be exhausted

A term widely used today is 'renewable energy', but exactly what is it? I have always been under the impression that once energy is used that is it! All the so called 'alternative' energy we use on Earth, be it wind, solar or geothermal comes from a non-renewable source. The sun, from which solar and wind energy is derived, is drawing daily on its non-renewable source of hydrogen which at some time in the distant future will be exhausted. Making time run backwards, which is impossible, is the only solution to renewable energy. Unfortunately, the Advertising Standards Agency has yet to challenge the validity of the statement. However, fortunately companies trying to cold sell 'renewable energy' stumble at the first hurdle as they are unable to satisfactorily define their product.

I'm not sure why we are bothering anyway as for millions of years millions of tons of oil have been discharging annually unchecked into the oceans. As millions of tons of oil will continue be to discharged annually for several million more years should fossil fuel not also be designated 'renewable energy' in the same way solar derived energy is?

Paul Shipman, Broughton Astley, Leics

Next letter: Reality which triumphs in the end