Solar-powered petrol station. Aerial view of the roof of a solar-powered petrol station, showing the photovoltaic cells which convert sunlight into electricity. These are thin film solar cells, consisting of layers of the semiconductors cadmium sulphide and cadmium telluride, sandwiched between two plates of glass. Energy from the Sun hitting the cells releases electrons in the semiconductors which are picked up and form an electric current. Enough energy is generated to power the petrol pumps and lights of this station. Photographed in Hammersmith, London, England.