Otherwise known as PV’s or SOLAR PANELS; these are rectangular flat devices that face the sun and generate electric power from its light. The energy of photons is used to energise electrons in the PV’s laminations). Three types of PV cells exist;
Mono-crystalline;
Poly-crystalline and;
Amorphous.
"Mono's" are the most efficient in terms of module area, and they generally last longer. Poly’s are slightly less efficient while amorphous cells are only half as efficient and have a shorter life-span (they are, however, cheaper).
A PV array is generally easy to install and the modular nature of such a system allows for easy upgrading. A south facing roof of any pitch is ideal. The solid state technology employed in the production of PV’s means that they are very reliable, lasting 30+ yrs.
If PV’s on their own have a drawback it is that they generate most power in the summer when it is not always needed, and less power in winter when needs are often greater. For this reason PV systems are often appropriately used on a seasonal basis (summer holidays) or incorporated as part of a WIND/PV hybrid system. Where cost is not so important a PV only system will provide year round power, however the number of modules, and hence cost, will be significantly greater. Planning permission is not usually required for PV’s.
The most common and least expensive PV systems consist of a PV array 'bolted on' to the roof, this means that it stands up slightly proud of the roof. More integrated systems involve removing the slates or tiles, fixing the array to the rafters and then re-fitting the slates/tiles around the array forming a waterproof barrier (similar to a Velux roof window). Also available, though more expensive, are 'Solar Slates/Tiles' which mimick the look of normal slates/tiles - though these integrated systems cost more.
Typically, in the UK, a 1 KW PV system (3m x 3m) will generate about 850KWh (units) of solar electricity per year - a 2KW system will produce double...
Typical costs (through SUSTAINERGY) are in the region of £4,500 / KW installed.
Site-assessment visits can be arranged prior to ordering - these are chargeable at £200 + 40p/mile travelled, but fully refundable upon ordering a system from us.
