Ī parabolic trough consists of a linear parabolic reflector that concentrates light onto a receiver positioned along the reflector's focal line. Thermal storage efficiently allows up to 24-hour electricity generation. In all of these systems a working fluid is heated by the concentrated sunlight, and is then used for power generation or energy storage. Various techniques are used to track the sun and focus light. Ī wide range of concentrating technologies exists: among the best known are the parabolic trough, the compact linear Fresnel reflector, the dish Stirling and the solar power tower. Such stand-alone power systems permit operations at night and at other times of limited sunlight.Ĭoncentrated solar power (CSP), also called "concentrated solar thermal", uses lenses or mirrors and tracking systems to concentrate sunlight, then use the resulting heat to generate electricity from conventional steam-driven turbines. In certain applications such as satellites, lighthouses, or in developing countries, batteries or additional power generators are often added as back-ups. In these grid-connected PV systems, use of energy storage is optional. Many residential PV systems are connected to the grid wherever available, especially in developed countries with large markets. Modules are wired together to form arrays, then tied to an inverter, which produces power at the desired voltage, and for AC, the desired frequency/phase. Multiple solar cells are connected inside modules. The array of a photovoltaic system, or PV system, produces direct current (DC) power which fluctuates with the sunlight's intensity.įor practical use this usually requires conversion to alternating current (AC), through the use of inverters. The surface passivation process has since been critical to solar cell efficiency. Atalla developed the process of silicon surface passivation by thermal oxidation at Bell Labs. These early solar cells cost US$286/watt and reached efficiencies of 4.5–6%. Following the work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the silicon solar cell in 1954. In 1931, the German engineer Bruno Lange developed a photo cell using silver selenide in place of copper oxide, although the prototype selenium cells converted less than 1% of incident light into electricity. The German industrialist Ernst Werner von Siemens was among those who recognized the importance of this discovery. The first solar cell was constructed by Charles Fritts in the 1880s. Schematics of a grid-connected residential PV power system Ī solar cell, or photovoltaic cell, is a device that converts light into electric current using the photovoltaic effect. Concentrated solar power (CSP) uses mirrors or lenses to concentrate sunlight to extreme heat to eventually make steam, which is converted into electricity by a turbine.Photovoltaic (PV) systems use solar panels, either on rooftops or in ground-mounted solar farms, converting sunlight directly into electric power.Solar power plants use one of two technologies: 3.5 Energy pricing, incentives and taxes.The International Energy Agency said in 2021 that under its "Net Zero by 2050" scenario solar power would contribute about 20% of worldwide energy consumption, and solar would be the world's largest source of electricity. Along with onshore wind, the cheapest levelised cost of electricity is utility-scale solar. Īs of 2021, solar generates 4% of the world's electricity, compared to 1% in 2015 when the Paris Agreement to limit climate change was signed.
Solar PV has rapidly become a viable low-carbon technology, and since 2020, provides the cheapest source of electricity in history. Millions of installations and gigawatt-scale photovoltaic power stations have been and are being built. Since then, as the cost of solar electricity has fallen, grid-connected solar PV systems have grown more or less exponentially. Commercial concentrated solar power plants were first developed in the 1980s. 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 PV system.
Concentrated solar power systems use lenses or mirrors and solar tracking systems to focus a large area of sunlight to a hot spot, often to drive a steam turbine. Photovoltaic cells convert light into an electric current using the photovoltaic effect. Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV), indirectly using concentrated solar power, or a combination.
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