Sunday 30 August 2015

Solar Power in England

I notice solar panels appearing on rooftops, and read of plans for whole farms of them in this part of Leicestershire. I welcome the saving of other fuels, but have two reservations.

First about solar power in England. Electricity consumption in England is highest in the Winter when sunshine is at its feeblest, and the peak demand is in the early evening, when it will be dark in Winter so that solar panels will yield nothing at all. Therefore, while solar panels will save fuel, they will not make it possible to close other power stations, We'll need just as many non-solar power generators as we should need if there were no solar power; we'll just use those other stations less frequently and so less economically.

Second I doubt whether large arrays of photoelectric panels are the best way to gather solar power. An alternative is to use mirrors to direct sunlight to a heat engine. Such a device can absorb all the energy in solar radiation, whereas a photovoltaic cell which uses a quantum effect can only use a fraction of the energy it receives. Also a heat engine can store enough heat to keep it working for a hour or two after dusk.





2 comments :

Sasha said...

I imagined that the electricity generated by these panels would be fed into the national grid and stored until required. Is this nonsense?

Richard said...

We have only a very limited capacity to store electricity. The only efficient method available is to run hydro-electric plants backwards, and what capacity we have for that is fully used to adjust supply to fluctuations in demand. There is no feasible method of storing power for more than a few hours. In particular the capacity of rechargeable batteries is orders of magnitude too small.

There's a lot of research into storage, but that is directed at ironing out day to day fluctuations in the output of wind turbines. There's no prospect of saving Summer power for use in the Winter.