MODEL RELEASED. Solar cell production. Worker with piles of photovoltaic, or solar, cells prior to them being assembled into solar panels. Photovoltaic cells convert light into electrical energy. The cells are made from a semiconductor, in this case silicon. When light hits the silicon it releases electrons that are picked up by a grid of wires and form an electrical current. Solar power is an environmentally-friendly energy source. Photographed at a Siemens factory in Germany.