Sunlight is all you need to get electricity from Solar Photo-Voltaic panels.
It is an unlimited resource that's never going to stop shining (even though it doesn't always feel like that in the UK). Although more electricity is produced on sunny days they work well on overcast days too. With the new Feed-in-tariffs announced under the Governments Clean Energy Cashback scheme there has never been a better time to invest in a solar PV system

Ideally for a photovoltaic system you should have a roof that faces between south east and south west, and which is free of shade. For a 1kW system you need about 8 square metres of roof space.
As a rough estimate a 1kW system will cost around £6,000, a 2kW system around £10-£10,500 and a 4kW system around £18,500-£19,000

Generate Money as well as Electricity

In April 2010 the Clean Energy Cashback scheme starts, and a 'Feed-in Tariff' (FIT) will be paid for each kWh of electricity generated by an eligible renewable energy electricity generating system.

The FIT for a Solar PV system of up to 4kW is 41.3pence per kwh produced, and pays for 25 years.
A 2kW system will generate approx 1600kwh annually, bringing in a FIT payment of around £660.
Added to this figure any electricity you generate but don't use within the home can be sold back to your Electricity Company via the National Grid - the proposed minimum price for exporting electricity is 3p per kWh, but may be higher depending upon your provider

Imagine you invest £10,000 on a 2kW solar PV system for your home, which produces 1,600kWh per year
It produces the most electricity during the middle of the day, when you are out at work and using the least amount of electricity yourself, so 40-50% of what the system generates may be sold back to the grid

You use 60% of the output, 960kWh, saving you 14p per kWh = £135
You sell 40% of the output, 640kWh, paying you 3p per kWh = £20
You get a FIT of 41.3p per kWh generated =£660
TOTAL RETURN TO YOU = £815

The return on your investment is therefore about 8.15% (rather better than you get at a bank !),
and they are to be index linked to keep in line with the inflation rate.
The FIT pays for 25 years - long after the system has paid for itself, and if you sell your house before the 25 years are up, then there is this income stream to be added onto the house value.

How Solar PV works

The photovoltaic panels on the roof convert the energy from the sun into a DC current. This is fed into an inverter which converts the DC current to a mains voltage AC current (there are safety switches placed on both sides of the inverter allowing any component to be safely isolated for servicing). The AC current is fed through a 'generation meter' into the main household fuse and distribution board. It is the generation meter that records the total amount of electricity generated - this is what you get paid on for the FIT

From the distribution board the electricity is either used by the appliances in your home, or fed back into the grid through a two way meter (or two separate meters) which record the amount of electricity you take from the grid, and the amount of electricity you export into the grid - it is this export meter that records what you sell to the electricity supply companies.