Turn your home into a power station! The Earth receives more energy from the Sun in just one hour than is used by humans worldwide in a whole year. Why not use it? This energy comes to us for free, and is now readily accessible. Photovoltaic cells convert daylight into electricity, reducing the need to exploit fossil fuels and thereby reducing the impact we have on the environment.

What is a Photovoltaic system?
A photovoltaic system comprises:
· Modules (panels) -usually on your roof - to convert solar energy into electricity
· A wiring system to connect to your electric system

A module consists of a number of photovoltaic cells made from semi-conducting material, usually silicon. These cells convert the Sun's rays into electricity using the Photovoltaic Effect. The Photovoltaic Effect has been known since the 19th century and was developed for use in space technology and again during the oil crises of the 1970s. The silicon technology has also benefited from developments in semi-conductors for the computer industry.

This page covers the use of PV to generate electricity for use in the home. Smaller systems, such as PV powered lights and fountains can be bought at large DIY stores or on the Internet.

Why install a photovoltaic system?

· You will be at the forefront of renewable energy developments.
· You will help alleviate global warming because a home system reduces carbon dioxide emissions by up to ¾ of a tonne per year.
· A small home system can typically provide 25% of your electricity needs, and in certain cases a lot more, particularly if you are more careful with your energy use. Some properties can generate 100% of their energy needs.
· A solar system will increase the value of your home.
· The systems are expected to last 30 years or more, need very little maintenance and are very reliable.
· Solar systems help safeguard against future rises in fuel prices, providing-inflation proof electricity for 30 years and more.

Installation

Home systems for generating electricity can be fitted by professional installers in as little as one day. For a list of installers accredited with the DTI grants scheme see here.

The fuel (daylight) is free but the cost of the system can vary quite considerably. A typical fully installed family system can cost over £10,000. However there is a government grant available to pay for up to 50% of the cost of the system, see below for details. In addition, if integrated into roof tiles or cladding then the cost of other building materials is also saved.

Is my home suitable?
You will need:
· A roof area that is not shaded by other buildings or trees.
· A suitable area of at least 10m2.
· The most effective roofs face between south-east and south-west.
· Solar panels do not usually need planning permission if they are not on the roadside of the house, do not project beyond the roofline and are not in a conservation area or on a listed building. It is advisable to check with your local authority.

Different Systems

Building Integrated or Bolt-On?

If you are improving your house you could consider a system designed into the building such as roof tiles. These systems will have shorter payback periods as you effectively only pay the difference between conventional roof tiles and solar ones. If you are not re-doing your roof, then modules mounted on the existing surface are probably the most cost effective option.

On-Grid or Off-Grid?

Grid-connected modules, mounted on the roof, provide electricity for the home and for selling to the Grid. No battery is needed, as the electricity is sold back to the supplier when you are not using it via an inverter which synchronises it with the mains supply.

Grid connection needs an agreement with the electricity supplier and can be arranged through accredited installers. It is possible to get a net metering deal where you get paid as much for the electricity you sell/export as you pay for the electricity you buy/import. However, with some electricity companies you may find you lose out financially due to the price difference between imported and exported electricity.

Crystalline or thin film cells?

Grants

What next?

For more information call the Green Energy Centre on:

020 8683 6683