Thursday, December 02, 2010

Solar electricity

A possible new strand to the blog - though it should be said that many other new strands have turned out to be very short. We're having solar PV panels installed in the next couple of weeks - assuming the foot of snow that is currently on the roof has gone in time - and I (obviously!) have a vested interest in seeing how this goes.

I've been interested in the potential for using the sun to generate energy locally for a while - both hot water and electricity. Investigations into the costs using the sort of supplier through whom it was possible to get the government subsidies up to relatively recently has made me decide not to do it. The price seemed to be based on the money you would save over the lifetime of the equipment. Here's another way to look at it. If economically the systems were good, companies wouldn't be selling the systems: they would be buying land to install the systems on.

With the feed-in tariff, this has changed. For solar photovoltaic electricity, you have always been able to generate your own electricity, and sell unused power back to the grid (albeit at a ridiculously low price - it's far more worthwhile to use it to reduce your own bill rather than make money back). Now, to encourage people to take up the scheme, the government is also paying a feed-in tariff, which is a much larger fixed amount per unit. The consequence of this is that it is now worthwhile for companies to basically install the systems wherever they can, and use the feed-in tariff to pay for the system. So there are quite a few companies who are now prepared for you to have a system installed "for free" and get free electricity from it, in return for them collecting the government tariff.

The company who we have gone with, Rayotec, discourage customers from doing this. They point out that, given the amount of the feed-in tariff, you are actually better off borrowing money (if possible) to install the system, as you will recover the cost early in the lifetime of the equipment. The equipment has an expected life of around 25 years - their PV panels are made by Schott, who have a 24 year old panel on the roof of their factory, which is still running at 95% of its designed capacity. And with the feed-in tariff, the cost of the system can be expected to be repaid in around 10 years.

We are expecting a 10-panel system to be installed, which should give us a 2.3 kWp system. In addition to this, the system needs an inverter (which converts the DC output of the panels into mains frequency AC), and the gubbins to connect it to the mains and metering system. The scaffolding should be arriving within two weeks, and the system should be installed early in the following week.

I'll keep you posted, dear reader....

No comments: