Solar thermal power plants use the heat from converted solar radiation to generate electricity. Like solar panels, they initially capture heat energy through the absorption of solar radiation and like photovoltaic cells, they generate electricity from sunlight. In short: they represent the most efficient means of utilizing solar energy.
The potential for solar thermal electricity generation that is technically achievable is several times greater than the worldwide electricity consumption. In contrast to photovoltaics, which are effective for low-power decentralized systems, solar thermal power plants generate electricity on a large scale - between 50 and 250 megawatts. With the integration of thermal storage, this power can then be supplied on demand, thus enabling solar power plants to generate electricity even after sunset. Solar thermal power plants therefore have the potential to replace fossil fuel power plants.
Solar thermal power plants is a general term referring to the various technologies. The distinction is made between concentrating systems, which focus the sunlight using reflectors, such as parabolic troughs, Fresnel reflector power plants, tower power plants, or solar dishes, and non-concentrating plants. With concentrating systems, the captured heat energy is usually fed into a steam cycle at temperatures significantly over 100 °C. As with conventional power plants, the steam is used in a turbine to generate electricity. In addition to concentrating systems, there are also non-concentrating systems which do not use reflectors, such as solar chimney power plants.
Solar Millennium focuses primarily on parabolic trough power plant technology. This technology is already in commercial use and has been tested over several years.