Concentrated solar power

Concentrated solar power (also called concentrating solar power, concentrated solar thermal, and CSP) systems generate solar power by using mirrors or lenses to concentrate a large area of sunlight onto a small area. Electricity is generated when the concentrated light is converted to heat (solar thermal energy), which drives a heat engine (usually a steam turbine) connected to an electrical power generator or powers a thermochemical reaction (experimental as of 2013). CSP had a world's total installed capacity of 5,500 MW in 2018, up from 354 MW in 2005. Despite no new capacity entering commercial operation in Spain since 2013, Spain accounted for almost half of the world's capacity, at 2,300 MW, making this country the world leader at the end of 2018. The United States follows with 1,740 MW. Interest is also notable in North Africa and the Middle East, as well as India and China. The global market has been dominated by parabolic-trough plants, which accounted for 90% of CSP plants at one point. The largest CSP projects in the world are the Ivanpah Solar Power Facility (392 MW) in the United States (which uses solar power tower technology), the Noor / Ouarzazate Solar Power Station (360 MW) in Morocco (which uses parabolic troughs) and Dhursar (125 MW) in India (which uses Fresnel reflector). In most cases, CSP technologies currently cannot compete on price with photovoltaic solar panels, which have experienced huge growth in recent years due to falling prices and much smaller operating costs. CSP generally needs large amount of direct solar radiation, and its energy generation falls dramatically with cloud cover. This is in contrast with photovoltaics, which can produce electricity also from diffuse radiation. However, an advantage of CSP over photovoltaic conversion is that as a thermal technology, a CSP plant can incorporate thermal energy storage, which stores energy either in the form of sensible heat, or as latent heat (for example, using molten salt), which enables these plants to continue to generate electricity whenever it is needed, whether day or night. This makes CSP a dispatchable form of solar. This is particularly valuable in places where there is already a high penetration of PV, such as California because an evening peak is being exacerbated as PV ramps down at sunset (a phenomenon referred to as duck curve). In 2017, CSP represented less than 2% of worldwide installed capacity of solar electricity plants. However, in recent years the falling prices of CSP plants are making this technology competitive with other base-load power plants using fossil and nuclear fuel even in high moisture and dusty atmosphere at sea level, such as the United Arab Emirates. Base-load CSP tariff in the extremely dry Atacama region of Chile reached below ¢5.0/kWh in 2017 auctions. A legend has it that Archimedes used a 'burning glass' to concentrate sunlight on the invading Roman fleet and repel them from Syracuse. In 1973 a Greek scientist, Dr. Ioannis Sakkas, curious about whether Archimedes could really have destroyed the Roman fleet in 212 BC, lined up nearly 60 Greek sailors, each holding an oblong mirror tipped to catch the sun's rays and direct them at a tar-covered plywood silhouette 49 m (160 ft) away. The ship caught fire after a few minutes; however, historians continue to doubt the Archimedes story. In 1866, Auguste Mouchout used a parabolic trough to producе steam for the first solar steam engine. The first patent for a solar collector was obtained by the Italian Alessandro Battaglia in Genoa, Italy, in 1886. Over the following years, invеntors such as John Ericsson and Frank Shuman developed concentrating solar-powered dеvices for irrigation, refrigеration, and locomоtion. In 1913 Shuman finished a 55 HP parabolic solar thermal energy station in Maadi, Egypt for irrigation. The first solar-power system using a mirror dish was built by Dr. R.H. Goddard, who was already well known for his research on liquid-fueled rockets and wrote an article in 1929 in which he asserted that all the previous obstacles had been addressed. Professor Giovanni Francia (1911–1980) designed and built the first concentrated-solar plant, which entered into operation in Sant'Ilario, near Genoa, Italy in 1968. This plant had the architecture of today's power tower plants with a solar receiver in the center of a field of solar collectors. The plant was able to produce 1 MW with superheated steam at 100 bar and 500 °C. The 10 MW Solar One power tower was developed in Southern California in 1981. Solar One was converted into Solar Two in 1995, implementing a new design with a molten salt mixture (60% sodium nitrate, 40% potassium nitrate) as the receiver working fluid and as a storage medium. The molten salt approach proved effective, and Solar Two operated successfully until it was decommissioned in 1999. The parabolic-trough technology of the nearby Solar Energy Generating Systems (SEGS), begun in 1984, was more workable. The 354 MW SEGS was the largest solar power plant in the world, until 2014.