Solar Gains

A. What do we mean by photovoltaics ? The word itself helps to explain how photovoltaic (PV) or solar electric technologies work. First used in about 1890,the word has two parts: photo a stem derived from the Greek phos, which means light, and volt, a measurement unit named for Alessandro Volta (1745-1827), a pioneer in the study of electricity. So photovoltaics could literally be translated into light electricity, and that's just what photovoltaics materials and devices do, they convert light energy into electricity, as Edmond Becquerel discovered in the 18th century.

A. When certain semi conducting materials, such as kinds of silicone, are exposed to sunlight, they release small amounts of electricity. This process is known as the "photoelectric effect" .The photoelectric effect refers to the emission , or ejection , of electrons from the surface of a metal in response to light. It is this basic process that a (PV) cell converts light into electricity.
Sunlight is made up of photons or particles of solar energy. Photons contains various amounts of energy, corresponding to the different wavelengths of the solar spectrum. When photons strike a PV cell they may be reflected or absorbed, or they may pass right through. Only the absorbed ones generate electricity. When this happens, the energy of the photon is transferred to an electron in an atom of the PV cell which is actually a semiconductor).

A. A huge amount of solar energy falls every year from the sun to the Earth, we can use this energy to power electrical energy for our Homes and Businesses , The energy falls onto the panels, which creates DC electricity, an inverter then converts this into AC electricity, which is then used to run your household or business needs.

A. The size of the installation will of course depend on the size of your roof space available. For example 8sqm of roof space can house a 1kw system which cost £5,000 to £6,500 or a 4kw system which would cost £8,000 to £11,000.

A. This depends on you the consumer, obviously the less you waste the less you need. To assess  your current needs add up your units consumed on your last 4 electricity bills, or contact your supplier and ask them what is your average electrical consumption is per annum. This is by far the best way to size a system rather than individual use. An average size 3 bed roomed semi detached house can produce 30-50% of its electrical needs using a 2kw system.

A. Your PV system does not need direct sunlight for it to work, even on cloudy days your PV system will still produce electricity.

A. In this case the system will allow energy to come into your home from the national grid. This will be necessary on winter days and of course night time when your PV system turns itself off.

A. In this case the system will export your additional electricity back into the national grid and of course you will be paid for it.

A. A well designed system will operate well in excess of the manufacturers 20 year warranty. The PV module with no moving parts has a lifetime expectancy of at least 30 years.

A. On a normal domestic home planning permission is not needed. However, iff your home is a listed building or in a conservation area, planning permission will be needed.
Those looking to install systems on commercial buildings should visit www.planningportal.gov.uk