What does the Energy Saving Trust say?

Cut your carbon footprint: Solar electricity is green, renewable energy and doesn't release any harmful carbon dioxide or other pollutants. A typical home Solar PV system could save over a tonne of carbon dioxide per year - that's around 30 tonnes over its lifetime.

Cut your electricity bills: Sunlight is free, so once you've paid for the initial installation your electricity costs will be greatly reduced.

Sell electricity back to the National Grid: If your system is producing more electricity than you need, or when you can't use it, you can sell the surplus back to the grid.

Source: http://www.energysavingtrust.org.uk/Generate-your-own-energy/Solar-panels-PV