Renewable energy is an integral part of the Government's longer-term aim of reducing CO2 emissions by 60% by 2050. The Government has set a target of 10% of electricity supply from renewable energy by 2010. In 2005, 4% of the UK's electricity supply came from eligible sources of renewable energy. During the same period, 4.2% of the UK's electricity supply came from all sources of renewable energy.

While it is anticipated that this target will predominantly met by the development of large scale renewable energy sites such as wind farms, the use of small scale domestic installations has an important part to play. These are outlined below:

Solar energy can be utilised in one of two ways, either the solar energy can be converted into electrical current (photovoltaics) or it can be converted into heat (active solar thermal).

• Photovoltaics
  The sun’s energy can be converted directly into electricity using photovoltaic cells. PV cells can be used for applications as small as watches and calculators, to large grid-connected arrays of panels. The great attraction of PV technology is that it delivers electricity at the point of use, for example panels can be integrated into buildings to supply the buildings themselves.
• Active Solar Thermal
  Active solar heating systems convert solar radiation into heat which can be used directly. In the UK uses are primarily domestic water heating and other low temperature heating applications such as swimming pools. In hotter climates a wider range of applications is possible, including electricity generation.
  Domestic water heating schemes consist of solar collectors, (usually) a preheat tank, pump, control unit, connecting pipes, the normal hot water tank, and backup heat source such as gas or electric immersion heater. The collectors are mounted on the roof and heat the water tank via a fluid circulated between the collectors and the tank. The overall area of the panels is typically 3-4 square metres.

Wind power equipment has been developed to provide a range of power outputs, from under 100W up to 3MW. The overall reliability of wind turbines is high - 97-99% availability is standard for modern turbines - and modern machines are designed to have a useful life of about 25 years. Turbines can have fixed or variable speed rotors, or in the case of small turbines can have furling rotor blades. When used for electricity generation, turbines can generate either direct or alternating current. The flexibility of design of individual turbine components means that machines can be matched to areas with high, medium or low average wind speeds and from the urban to rural.

Ground source heat pumps use a buried ground loop which transfers heat from the ground into a building to provide space heating and, in some cases, to pre-heat domestic hot water. As well as ground source heat pumps, air source and water source heat pumps are also available. The system does not require any external fuel and is designed to heat a whole building.

The efficiency of a ground source heat pump system is measured by the coefficient of performance (CoP). This is the ratio of units of heat output for each unit of electricity used to drive the compressor and pump for the ground loop. Typical CoPs range from 3 to 4. This means that for every unit of electricity used to pump the heat, 3-4 units of heat are produced, making it an efficient way of heating a building. A ground source heat pump can have lower running costs than oil, LPG, coal and electric heating systems, however it is more expensive than mains gas. If grid electricity is used for the compressor and pump, then you should consult a range of energy suppliers to benefit from the lowest running costs, for example by choosing an economy 10 or economy 7 tariff.