by ValleyEstate » 27 Jan 2011, 19:59
They consist of a semiconductor junction which has an uneven distribution of charge so it has an electric field in it. When light hits the material, an electron is knocked off from its parent atom and can move around the material. The electric field pushes it in one direction, et voila. You have current!
(it's most complicated than that, but it needs quantum physics to understand).
In summary, light goes in and DC electricity comes out of the panel.
To use it in your house you will need an inverter as well, which turns it into useful AC. Then you need a way of using up the extra electricity you produce when it's sunny but you're not using power Some people use batteries, most people use 'grid tied' systems, plug in to the national grid and sell electricity to power companies that you're not using!
Unfortunately, without major subsidies (like those offered in Germany, Japan and soon the UK), solar panels aren't likely to be cost effective. In the UK it costs about £5-6,000 to install a kWp of solar power and it will make about £90 of electricity a year. In California it's sunnier, so would make about £200 of electricity a year, but it's still very VERY expensive without subsidy.
On the plus side, technology is improving. Thin film technology can be done at half the price, so I'd say hold on until thin film solar cells go up for sale (right now they only sell them to companies for big projects). Prices should drop by at least half in the coming years if they can make enough to sell to households - and at that price it'll be worth it in places like California.