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, solar thermal power plants represent the most efficient means of capturing, converting and transmitting solar energy to utility companies and, ultimately, end users.
The potential for solar thermal electricity generation is immense. Solar thermal electricity is capable of generating power that is multiple 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 long after sunset. As a result, solar thermal power plants have the potential to replace fossil fuel power plants, with no carbon emissions and little environmental impact.
Solar thermal power plants is a general term referring to several different technologies. The distinction is made between concentrating systems, which focus the sunlight using reflectors, such as parabolic troughs. With concentrating systems, the captured heat energy is typically fed into a steam cycle at temperatures around 700 °F. As with conventional fossil-fuel power plants, the steam is used to drive 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 Trust of America and its business partners concentrate primarily on parabolic trough power plant technology. This technology is already in commercial use and has been operating successfully in California’s Mojave Desert since 1985, feeding “peak load” electricity to the California power grid during high demand periods.