There are three ways in which photovoltaic solar panels can make you better off.

1. Avoided import = lower electricity bills: When the solar panels are producing electricity that can be consumed on-site; it does not need to be purchased.

2. Income from export: Excess electricity generated by the solar panels, that is not required on-site is delivered to the grid and can be sold to energy supply companies with a minimum guaranteed tariff of 3p /kWh or can be negotiated higher with your utility supplier.

3. Feed in Tariff: From 1 April 2010 householders and communities who install PV up to 5 megawatts will also be paid for the electricity they generate, even if they use it themselves. The level of payment is linked to inflation.

These payments will be in addition to benefiting from reduced bills as they reduce the need to buy electricity. The scheme will also apply to installations commissioned since July 2009 when the policy was announced. Tariff levels have been calculated to offer between 5-8% return on initial investment.

Output from PV solar panels: Approximately 8m2 of photovoltaic panels will provide a maximum power output of 1kW. In the south of England a south facing 1 kW array aligned at 35° would produce in the region of 1,000-1,200kWh/annum.

Microgeneration tariffs: Different energy companies run export agreements and ROC contracts in various ways.