Solar power
Photovoltaic systems convert the sun's radiation into electrical energy by means of solar cells. The heart of each solar cell is a semi-conductor, in most cases silicon. The sunlight is converted into direct current, which is used directly to operate electrical equipment or is stored in batteries. Direct current can also be converted into alternating current and fed into the public grid. At the end of 2010, photovoltaic systems with an output of around 16,910 MW electrical power were installed in Germany, which cover the power requirements for more than 3.4 million three-person households.
Solar thermal power plants generate electricity by concentrating and amplifying the sun's radiation. The radiation is concentrated via reflectors and is converted into steam with which a generator is operated. Solar thermal electricity generation is used above all in Spain and the USA. Test systems are in operation in Germany. German universities and companies are technological leaders in research and the manufacture of components.