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Why is it important? Photovoltaic (PV) panels harness energy from the sun to produce electricity. PV panels can produce electricity without releasing carbon dioxide(CO2), which contributes to climate change. The also do not produce air pollution or contaminate the sea or land during operation. Manufacture of PV panels does not cause any major environmental impacts when compared to other industrial processes. How does work? Electricity can be generated directly from sunlight using Photovoltaic (PV) systems. The output of a PV system depends on the size and efficiency of the panels. There are a number of different types of PV panel which are suited to different uses. The efficiency and cost of these panels varies. In the UK PV panels are usually incorporated into the structure of buildings or appliances rather than set out as a central power station. This means that power is generated close to where it is needed and the PV can replace roofing or cladding materials. |
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The energy captured by PV panels can be used directly or stored in batteries. If a PV system is grid connected, electricity can be "imported" from the grid when there is little sunlight and excess electricity "exported" to the grid in bright sunlight. This means batteries are not needed. What does it look like? The most typical form of PV is a rectangular black or dark blue panel. There is increasing variations in the appearance of PV units as PV coatings can now be added to many different materials such as:
PV coatings can even be added to some fabrics. Flexible panels are available and PV clothing may be introduced over the next few years. |
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How much energy can it generate? In the UK there are a number of houses which supply all or most of their own electricity needs from roof mounted solar panels. This is achieved by combining the PV system with energy efficiency measures to reduce electricity demand. Most new buildings could be designed to incorporate PV into either roofing or cladding materials making them at least partly self sufficient in electricity. How much does it cost? PV is quite expensive but costs have been decreasing consistently for the last decade. As system to provide most of the electricity for an average household would currently cost around £15-30,000. Research by the PV industry and environmental groups suggests that, with the right level of investment, PV could supply electricity at the same price as fossil fuels within 10 years. |
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Where should it be sited? Look for a roughly SE to SW facing location (the closer to South the better). Shading of PV panels reduces the amount of energy produced, so unshaded areas are best. PV can be placed on angled roof or vertical walls. Placing PV panels on a horizontal surface reduces the amount of energy captured during the winter when the sun is low in the sky. PV does not have to be located on the roof. It could, for example, be mounted on a pergola in the garden. |
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Where a site is not connected to the national grid PV can be cheaper than grid connection and is cleaner and quieter than a diesel generator. Examples of off-grid sites might be remote households or telecommunications systems. Other examples of good sites for off-grid use of PV might be a remote holiday chalet or a boat. There are mainly used in the summer when PV is most productive. It is possible to buy small appliances which are powered by their own PV panel and battery. Examples of these are torches, radios, battery chargers, power systems for boats, caravans and even doorbells. PV powered garden fountains and lighting can be a good buy as they save bringing power cables from the house into the garden. |
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Further information:
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