What is  Solar Power ?

Solar power uses the huge amount of energy that reaches the earth from the sun. Just a tiny fraction of this energy is enough to meet all our energy needs many times over.

There are several technologies available to harnass this abundant, free resource.

Active Solar Heating

How does the technology work?

Active solar heating captures and stores the heat from the sun using a water storage system.

All the different systems capture the heat from the sun and transfer it to a water tank through a heat exchanger.

There are three types of solar collector that can be used: evacuated tubes, flat plate collectors and unglazed plastic collectors.

Evacuated tubes and flat plate collectors are used for houses and other buildings. Unglazed plastic collectors are used for heating swimming pools, where a lower temperature is required, and are less expensive.

Suitable for the UK?

This technology is commerically available now and is in use in the UK. It can be used to heat swimming pools, domestic hot water, commercial properties and industrial processes. There are 21 million homes in the UK that have the potential to use active solar heating.

The benefits

There are over 100,000 installed active solar heating systems in the UK. A good-quality, well-designed system can make a significant contribution to reducing energy bills.

An active solar heating system can provide up to 2,000kWh, enough for 50% of the hot water needs for a family of four and last for about 20 years.

Solar Photovoltaics

How does the technology work?

Solar photovoltaic (PV) cells generate electricity from light using a semiconductor material. This is a material that releases electrons whenit is exposed to light. 98% of solar PV today uses silicon as a semiconductor, but other materials are in development.

There are four types of PV cells currently available:

• Monocrystalline - the most efficient in good light conditions
• Polycrystalline - highly efficient for good light conditions
• Thin-film - the most efficient in poor light, sturdy and vandal proof
• Hybrid - a combination of monocrystalline and thin-film technologies. Excellent performance in poor light conditions.

Solar PV can be used in a variety of ways to replace orthodox building materials to generate electricity from the building itself. These can include roof tiles, cladding, louvres, glazing or panels.

PV systems can be connected to the national grid, with excess electricity being sold onto your electricity company.

An off-grid system is independent of the national grid and the electricity is stored and is the main source of power for the property. PV can be combined with other sources of power, such as biomass or a wind turbine as part of a decentralised energy generation system.

Suitable for the UK?

Solar PV systems have been installed in a variety of properties in the UK, from houses to office buildings. Investment from the government in solar PV will result in a reduction in costs, which could yield a further 500MW of installed capacity.

Off-grid solar PV is cheaper than grid-connection for street furniture such as bus shelters, bus stops, parking meters and street lighting, and there are thousands of these systems already running across the UK.

The benefits

Solar PV has an important part to play in a decentralised energy system, making use of the free resource the sun provides, reducing our dependence on fossil fuels and lowering carbon emissions in the process.

Passive Solar

How does the technology work?

Passive solar is a design principle that should be incorporated in all new properties. It uses south-facing windows to ensure the sun's heat is captured and insulation to ensure that excess heat loss is avoided.

Passive solar reduces the need for heating and lighting from conventional sources of energy and makes energy efficience integral to the way a property is constructed.

Suitable for the UK?

Passive solar design is a proven approach to building and is the simplest form of solar energy.

Location and orientation of the building are key factors so it is best applied in new buildings. Studies on properties in Milton Keynes have proven that passive solar design features, draught proofing and insulation reduced heating bills by 40%, with the savings paying back any extra costs within two years.

The benefits

By using passive solar design in new buildings, fuel bills can be cut by a third. With increased free daylight, the need to use artifical lighting is reduced.