ABSTRACT
There is a surprising range of different technologies for the sustainable generation of electricity. These fall within two main classes: climatic or 'elemental' sources and fuel-powered or 'bioenergy' sources. The conversion of light to electricity in a semiconductor device is known as photovoltaics. A solar cell is a semiconductor wafer or film, treated so that when struck by photons of light, positive and negative charges are released. The Renewables ObligationB15 (RO) was introduced in 2002 and placed a requirement on licensed electricity suppliers to procure from renewable sources a growing proportion of the electricity which they sell. Two government schemes have been specifically designed to provide financial support to renewable electricity generating systems. The RO is available for projects over 50 kW and there is no upper limit. ROCs are delivered by the energy regulator Ofgem to all accredited generating stations, nominally at the rate of one ROC per megawatt-hour produced.
