According to some recent studies, in the year 2050 more than 15 per cent of electricity used worldwide could be generated by concentrating solar systems. These systems are power plants which concentrate direct solar irradiation and use the heat yield to produce power through a steam turbine and generator.
Today, solar thermal power plants already provide over a million people with electricity. Therefore, the market for concentrating solar systems is seen as a very interesting growing market for future renewable power generation. In July, 2009, European energy companies and the Desertec foundation initiated a project to generate power for Europe in North African solar power plants.
The 15th SolarPACES conference, the latest in a long series of international conferences initiated by the SolarPACES Network of the International Energy Agency (IEA) in 1980 is already fully booked out and has achieved record numbers of participants registered. 16 different countries are involved in this Implementing Agreement, working together in the field of solar thermal power generation.
The experts will address the following topics:
* the current market and perspectives for this form of solar power generation
* political initiatives and programs worldwide to support market entry
* cooperation with countries in the southern Mediterranean region on use of technology and the possibilities of exporting power to Europe
* operational experience from the solar power plants currently in operation in many countries
* new technical developments for further areas of application and for cost reduction in solar thermal technology
Concentrating solar power (CSP) systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. The concentrated light is then used as a heat source for a conventional power plant or is concentrated onto photovoltaic surfaces.
Concentrated sunlight has been used to perform useful tasks from the time of ancient China. A legend claims that Archimedes used polished shields to concentrate sunlight on the invading Roman fleet and repel them from Syracuse. As legends go, this was probably not possible. In 1866, Auguste Mouchout used a parabolic trough to produce steam for the first solar steam engine. Over the following 50 years, inventors such as John Ericsson and Frank Shuman developed concentrating solar-powered devices for irrigation, refrigeration, and locomotion.
Concentrating solar thermal (CST) is used to produce renewable heat or electricity (generally, in the latter case, through steam). CST systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. The concentrated light is then used as heat or as a heat source for a conventional power plant (solar thermoelectricity).
A wide range of concentrating technologies exist, including the parabolic trough, Dish Stirling, Concentrating Linear Fresnel Reflector, Solar chimney and solar power tower. Each concentration method is capable of producing high temperatures and correspondingly high thermodynamic efficiencies, but they vary in the way that they track the Sun and focus light. Due to new innovations in the technology, concentrating solar thermal is being more and more cost-effective.
A parabolic trough consists of a linear parabolic reflector that concentrates light onto a receiver positioned along the reflector’s focal line. The receiver is a tube positioned right above the middle of the parabolic mirror and is filled with a working fluid. The reflector follows the Sun during the daylight hours by tracking along a single axis. A working fluid (eg molten salt is heated to 150-350 °C as it flows through the receiver and is then used as a heat source for a power generation system. Trough systems are the most developed CSP technology. The Solar Energy Generating Systems (SEGS) plants in California, Acciona’s Nevada Solar One near Boulder City, Nevada, and Plataforma Solar de Almería’s SSPS-DCS plant in Spain are representative of this technology.
Concentrating Linear Fresnel Reflectors are CSP-plants which use many thin mirror strips instead of parabolic mirrors to concentrate sunlight onto two tubes with working fluid. This has the advantage that flat mirrors can be used which are much cheaper than parabolic mirrors, and that more reflectors can be placed in the same amount of space, allowing more of the available sunlight to be used. Concentrating Linear Fresnel reflector can come in large plants or more compact plants.
A Dish Stirling or dish engine system consists of a stand-alone parabolic reflector that concentrates light onto a receiver positioned at the reflector’s focal point. The reflector tracks the Sun along two axes. The working fluid in the receiver is heated to 250-700 °C and then used by a Stirling engine to generate power. Parabolic dish systems provide the highest solar-to-electric efficiency among CSP technologies, and their modular nature provides scalability. The Stirling Energy Systems (SES) and Science Applications International Corporation (SAIC) dishes at UNLV, and the Big Dish in Canberra, Australia are representative of this technology.
A Solar chimney consists of a transparent large room (usually completely in glass) which is sloped gently up to a central hollow tower or chimney. The sun heats the air in this greenhouse-type structure which then rises up the chimney, hereby driving an air turbine as it rises. This air turbine hereby creates electricity. Solar chimneys are very simple in design and could therefore be a viable option for projects in the developing world.
A solar power tower consists of an array of dual-axis tracking reflectors (heliostats) that concentrate light on a central receiver atop a tower; the receiver contains a fluid deposit, which can consist of sea water. The working fluid in the receiver is heated to 500-1000 °C and then used as a heat source for a power generation or energy storage system. Power tower development is less advanced than trough systems, but they offer higher efficiency and better energy storage capability. The Solar Two in Daggett, California and the Planta Solar 10 (PS10) in Sanlucar la Mayor, Spain are representative of this technology.
Concentrating Solar Thermal Power (CSP) is the main technology proposed for a cooperation to produce electricity and desalinated water in the arid regions of North Africa and Southern Europe by the Trans-Mediterranean Renewable Energy Cooperation DESERTEC.
The CSTP industry saw many new entrants and new manufacturing facilities in 2008. Active project developers grew to include Ausra, Bright Source Energy, eSolar, FPL Energy, Infinia, Sopergy, and Stirling Energy Systems in the USA. In Spain, Abengoa Solar, Acciona, Iberdrola Renovables, and Sener were active in 2008.
Solar thermal power stations
This is a list of solar thermal power stations. These include the 354 megawatt (MW) Solar Energy Generating Systems power plant in the USA, Nevada Solar One (USA, 64 MW), Andasol 1 (Spain, 50 MW), PS20 solar power tower (Spain, 20 MW), and the PS10 solar power tower (Spain, 11 MW).
The solar thermal power industry is growing rapidly with 1.2 GW under construction as of April 2009 and another 13.9 GW announced globally through 2014. Spain is the epicenter of solar thermal power development with 22 projects for 1,037 MW under construction, all of which are projected to come online by the end of 2010. In the United States, 5,600 MW of solar thermal power projects have been announced. In developing countries, three World Bank projects for integrated solar thermal/combined-cycle gas-turbine power plants in Egypt, Mexico, and Morocco have been approved.
* Martin Next Generation Solar Energy Center — Florida, USA, 75 MW steam input into a combined cycle, parabolic trough design.
* Andasol 2–3 — Granada, Spain, 50 MW each with heat storage, parabolic trough design.
* Alvarado/La Risca 1 solar power station — Badajoz, Spain, 50 MW , parabolic trough design.
* Solnova 1, 3 solar power station — Spain, 50 MW , parabolic trough design.
* Extresol 1 solar power station — Spain, 50 MW , parabolic trough design.
* Kuraymat Plant — Egypt, 40 MW steam input for a gas powered plant, parabolic trough design.
* Hassi R’mel integrated solar combined cycle power station — Algeria, 20 MW steam input for gas powered plant, parabolic trough design.
* Beni Mathar Plant — Morocco, 20 MW for hybrid power plant, technology unknown.
* Solar Tres Power Tower — Spain, 17 MW with heat storage, power tower design.
* Solar demonstration plant — 5 MW, Lancaster, California.
* Extresol 2–3 — Badajoz, Spain, 50 MW each with heat storage, parabolic trough design.
* Andasol 4–7 — Granada, Spain, 50 MW each with heat storage, parabolic trough design.
* Manchasol 1–2 — Ciudad Real, Spain, 50 MW each with heat storage, parabolic trough design.
* Solnova 2, 4–5 — Sevilla, Spain, 50 MW each with heat storage, parabolic trough design.
* Ecija 1–2 — Ecija, Spain, 50 MW each with heat storage, parabolic trough design.
* Helios 1–2 — Ciudad Real, Spain, 50 MW each with heat storage, parabolic trough design.
* Termesol 50 — Seville, Spain, 50 MW with heat storage, parabolic trough design.
* Arcosol 50 — Cadiz, Spain, 50 MW with heat storage, parabolic trough design.
* Ibersol Badajoz — Fuente de Cantos, Spain, 50 MW, parabolic trough design.
* Ibersol Valdecaballeros 1–2 — Valdecaballeros, Spain, 50 MW, parabolic trough design.
* Ibersol Sevilla — Aznalcollar, Spain, 50 MW, parabolic trough design.
* Ibersol Almería — Tabernas, Spain, 50 MW, parabolic trough design.
* Ibersol Albacete — Almansa, Spain, 50 MW, parabolic trough design.
* Ibersol Murcia — Lorca, Spain, 50 MW, parabolic trough design.
* Ibersol Zamora — Cubillos, Spain, 50 MW, parabolic trough design.
* Enerstar Villena Power Plant — Villena, Spain, 50 MW, parabolic trough design.
* Aste 1A, 1B, 3, 4 — Alcázar de San Juan (Ciudad Real), Spain, 50 MW each, parabolic trough design.
* Astexol 1–2 — Extremadura, Spain, 50 MW each, parabolic trough design.
* Palma del Rio 1–2 — Cordoba, Spain, 50 MW each, parabolic trough design.
* AZ 20 — Sevilla, Spain, 20 MW , power tower design.
* Almaden Plant — Albacete, Spain, 20 MW, power tower design.
* Gotasol — Gotarrendura, Spain, 10 MW, linear fresnel design.
* Aznalcollar TH — Sevilla, Spain, 80 kW, dish sterling design.
* Negev Desert, Israel, 250 MW, design will be known after tender.
* Upington, South Africa, 100 MW, power tower design.
* Shams, Abu Dhabi Madinat Zayad, 100 MW, parabolic trough design.
* Yazd Plant — Iran, 67 MW steam input for hybrid gas plant, technology unknown.
* Archimede — near Siracusa, Sicily, Italy, 28.1 MW with heat storage, parabolic trough design.
* Solenha — Aspres sur Buëch, France, 12 MW with heat storage, parabolic trough design.
* Cloncurry solar power station — Australia, 10 MW with heat storage, power tower design.
* Nagpur, India, 10 MW, design unknown.
Out of commission
* Solar One (converted into Solar Two) — USA California, 10 MW, power tower design.
* Themis (under rehabilitation) — France, 2 MW, power tower design.
* SES-5 — USSR, 5MW, power tower design, water / Steam, service period 1985-1989.