Photovoltaics

PV cells are suitable for any building with a southeast to southwest facing roof with no over shadowing.

Solar photovoltaic (PV) panels are used to generate electricity. They should ideally be installed in an unshaded location at between 30-45° to the horizontal and facing between southeast and southwest. They can be installed on pitched roofs, flat roofs or ground mounted.

Solar Photovoltaics - Specifications
Typical Domestic System PV panels generate DC electricity, which needs to be passed through an inverter to synchronise with the grid and service AC appliances in the house. A typical domestic installation usually comprises 8 to 16 panels (2 to 4 kWp of generating capacity), requiring around 12 to 24 m² of roof-space.
System Costs Typically £8,000 - £14,000 (£3-4,000 per kW) The estimated lifetime of the panels is greater than 25 years and maintenance costs are very low.
Energy Savings As a general rule you can expect to generate around 750 to 800 kWh per kW of PV. So a 4 kWp system should generate around 3,000 kWh per year, and save 1.6 tonnes of CO₂.
Feed in Tariff (FIT) Since April 2010 the FIT has been available for PV in the UK. For retrofit systems <4 kWp the current tariff rate is 43.3p/kWh, which is paid for all electricity generated. If you use that electricity yourself you offset the cost of buying electricity from the grid (typically at 12p/kWh) and if you export it, you are paid an additional 3p/kWh export tariff. Example 4 kWp System (assuming you use 50% of electricity generated and export 50% to the grid): FIT: 3,000 kWh x 43.3p/kWh = £1,299 Export: 1,500 kWh x 3p/kWh = £45 Savings on your electricity bill: 1,500 kWh x 12p/kWh = £180 So in this example you would be £1,524 per year better off... The FIT for PV is index linked for 25 years. Visit the DECC website for more information and to check the latest tariff rates.
Development issues PV panels are now permitted development, however restrictions apply and planning permission will be required for installations on listed buildings, in conservation areas and for most ground mounted systems. A building warrant will be required for most roof mounted installations.
More information Solar Energy Association Energy Saving Trust

Solar Photovoltaics - Specifications

Typical Domestic System

PV panels generate DC electricity, which needs to be passed through an inverter to synchronise with the grid and service AC appliances in the house.

A typical domestic installation usually comprises 8 to 16 panels (2 to 4 kWp of generating capacity), requiring around 12 to 24 m² of roof-space.

System Costs

Typically £8,000 - £14,000 (£3-4,000 per kW)

The estimated lifetime of the panels is greater than 25 years and maintenance costs are very low.

Energy Savings

As a general rule you can expect to generate around 750 to 800 kWh per kW of PV. So a 4 kWp system should generate around 3,000 kWh per year, and save 1.6 tonnes of CO₂.

Feed in Tariff (FIT)

Since April 2010 the FIT has been available for PV in the UK.

For retrofit systems <4 kWp the current tariff rate is 43.3p/kWh, which is paid for all electricity generated. If you use that electricity yourself you offset the cost of buying electricity from the grid (typically at 12p/kWh) and if you export it, you are paid an additional 3p/kWh export tariff.

Example 4 kWp System (assuming you use 50% of electricity generated and export 50% to the grid):

FIT: 3,000 kWh x 43.3p/kWh = £1,299
Export: 1,500 kWh x 3p/kWh = £45
Savings on your electricity bill: 1,500 kWh x 12p/kWh = £180
So in this example you would be £1,524 per year better off...

The FIT for PV is index linked for 25 years.

Visit the DECC website for more information and to check the latest tariff rates.

Development issues

PV panels are now permitted development, however restrictions apply and planning permission will be required for installations on listed buildings, in conservation areas and for most ground mounted systems.

A building warrant will be required for most roof mounted installations.