Solar weakness

Geoff Moore (Letters, 24 July) rightly draws attention to some, but not the worst, of the absurdities of solar electricity in Britain.

While wind power cannot be relied upon due to the vagaries of the weather, the well-defined nature of our seasons means that solar power can be relied upon. It can be relied upon never to be there when it is most needed.

The output of solar panels at about the latitude of London varies entirely predictably by a factor of five between summer and winter.

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In Scotland this variation will be even larger. This means only about 5 per cent of a solar installation’s annual output is available in December and January, the time of highest electricity demand.

Solar electricity is indeed a practical and economic proposition closer to the equator where it is sunnier and where seasonal variations are much smaller.

Furthermore, it is convenient for providing distributed generation in developing countries without an effective grid system.

Most importantly it can replace environmentally and health-damaging alternatives such as paraffin lamps which emit carbon dioxide and soot, the latter having many times the global warming impact of carbon dioxide.

It is absurd and rather shameful that European governments, including our own, subsidise ineffective solar panels here when a fraction of this money spent in the developing world could significantly improve health, education and quality of life.

A 4kW domestic solar panel system in the UK costs around £8,000 and might remit at most 1,600kg of carbon dioxide annually. The same sum could replace about 1,600 of the billion or so paraffin lamps in Africa and Asia with solar lighting, remitting the equivalent of about 600 tonnes of carbon dioxide and providing several hundred people with a healthier and better lit environment.

(Prof) Jack Ponton, FREng

Scientific Alliance Scotland