There are many different technologies to generate electricity from solar energy. Most of them fall into two main categories: photovoltaic (PV) and concentrated solar power (CSP) systems, which each harness solar energy in very different ways.
PV technologies generate electric current directly and immediately as the sun’s radiant energy is absorbed by a PV panel's semiconductors. These are the ubiquitous rectangular panels that most people associate with solar energy and are used in applications as diverse as pocket calculators, emergency telephones, and home and commercial rooftops. There are also a growing number of large utility-scale PV systems that help power the electric grid too.
CSP technologies, also called solar thermal energy, typically use mirrors to focus sunlight and heat a liquid (or gas). As the liquid is heated by the sun, it evaporates and becomes steam. The rising steam turns a turbine, which generates electricity. The turbine component of CSP technologies is similar to those used in traditional power plants, which use energy from coal, nuclear fission, or natural gas, instead of the sun, to generate steam. Some CSP facilities are also able to store the sun's heat for hours after the sun has gone down and can continue to generate electricity even at night.