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Boiling a kettle with solar power

David Gregory | 18:18 UK time, Wednesday, 29 September 2010

Stoke solar panels

So on a rainy street in Stoke this morning I did a quick "back of the envelope calculation" trying to work out how many cups of tea we could have using some recently installed solar panels.

I came to the conclusion it was about 900 or so, but I think that might be a bit on the generous side. The solar panels in question had generated 11KWh of electricity since they were installed on Friday. (KWh stands for kilowatt hour and is the unit used by the power companies when charging us for electricity)

Back in the office I've been checking the energy used by various kettles and it's about 0.15KWh to boil a full kettle. So the energy generated by the solar panels would let us boil just over 70 kettles. If we say you get ten cups out of a kettle that gives us more like 700 cups of tea rather than the 900 I mentioned.

Of course all this depends on your kettle!

We can be much more certain about what these 11KWh are worth in terms of solar subsidy. The government will pay 43p for every 1KWh produced. The Council in Stoke hope a house could generate £500 a year in subsidy. That means the solar panels would pay for themselves in 12 years. Since it's claimed they will last for 25 years anything after that is pure (subsidised) profit.

Why such a large subsidy? Well the idea is to kick-start the solar industry in the UK. In Stoke although they import the panels themselves they hope to create work for local companies who will install and maintain them.

Despite some suggestions otherwise electricity company E.ON say if panels are installed now you will "lock-in" this 43p subsidy for the lifetime of the solar panels. For a council like Stoke that's a pretty good return.

11KWh of energy


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