Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics convert light into an electric current using the photovoltaic effect.
The International Energy Agency projected in 2014 that under its "high renewables" scenario, by 2050, solar photovoltaics and concentrated solar power would contribute about 16 percent, respectively, of the worldwide electricity consumption, and solar would be the world's largest source of electricity.
Photovoltaics were initially solely used as a source of electricity for small and medium-sized applications, from the calculator powered by a single solar cell to remote homes powered by an off-grid rooftop system. As the cost of solar electricity has fallen, the number of grid-connected solar photovoltaic systems has grown into the millions and utility-scale solar power stations with hundreds of megawatts are being built. Solar photovoltaic systems are rapidly becoming an inexpensive, low-carbon technology to harness renewable energy from the Sun.
Commercial concentrated solar power plants were first developed in the 1980s. The 392 MW Ivanpah installation is the largest concentrating solar power plant in the world, located in the Mojave Desert of California. The 579 MW Solar Star, near Rosamond, California, is the world's largest PV power station.