Photovoltaics - Solar Power
Photovoltaic cells (PVs) convert energy from sunlight into electricity. PVs are also able to convert ultra violet rays into electricity and therefore still operate when there isn’t direct sunlight – but less efficiently. PV’s are manufactured in a variety of forms – they can be installed as stand alone panels or form part of a roof itself with the PVs embedded in a tile “substitute”. They also can be incorporated as transparent cells that can be used in windows (roof lights) and conservatories.
Each PV cell consists of two layers of semiconducting material (frequently silicon). The sunshine creates an electric field across the layers and thus electricity is produced. The greater the sunshine the more power is produced.
PVs should be mounted on roofs or similar mounts within 90° of south. Clearly there wants to be no overshadowing by trees or other properties as this will reduce the potential efficiency of the panel. The panels are heavy and therefore roof structures must be strong enough or be strengthened to bear the additional weight. However tile substitute systems can be used to reduce the weight loading. A typical domestic pv system might generate around 50% of the home’s power requirement.
For more information download the Photovoltaic FACT sheets