Concentrated solar power

largest CSP Project in the world has been installed in Abu Dhabi, by Masdar.[5] CSP growth is expected to continue at a fast pace. As of January 2014, Spain had a total capacity of 2,204 MW making this country the world leader in CSP. Interest is also notable in North Africa and the Middle East, as well as India and China. The global market has been domi- nated by parabolic-trough plants, which account for 90% of CSP plants.[4] CSP is not to be confused with concentrated photovoltaics (CPV). In CPV, the concentrated sunlight is converted The PS10 Solar Power Plant concentrates sunlight from a field directly to electricity via the photovoltaic effect. of heliostats onto a central solar power tower.

1 History

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 160 feet away. The ship caught fire after a few minutes; however, historians con- tinue to doubt the Archimedes story.[6] Part of the 354 MW SEGS solar complex in northern San In 1866, Auguste Mouchout used a parabolic trough to Bernardino County, California. produce steam for the first solar steam engine. The first patent for a solar collector was obtained by the Italian Concentrated solar power (also called concentrating Alessandro Battaglia in Genoa, Italy, in 1886. Over solar power, concentrated solar thermal, and CSP) the following years, inventors such as John Ericsson and systems generate solar power by using mirrors or lenses Frank Shuman developed concentrating solar-powered to concentrate a large area of sunlight, or solar thermal devices for irrigation, refrigeration, and locomotion. In energy, onto a small area. Electricity is generated when 1913 Shuman finished a 55 HP parabolic solar thermal the concentrated light is converted to heat, which drives energy station in Maadi, Egypt for irrigation.[7][8][9][10] a heat engine (usually a steam turbine) connected to an The first solar-power system using a mirror dish was built electrical power generator or powers a thermochemical by Dr. R.H. Goddard, who was already well known for reaction (experimental as of 2013).[1][2][3] his research on liquid-fueled rockets and wrote an article in 1929 in which he asserted that all the previous obsta- CSP is being widely commercialized and the CSP mar- [11] ket has seen about 740 MW of generating capacity added cles had been addressed. between 2007 and the end of 2010. More than half of Professor Giovanni Francia (1911–1980) designed and this (about 478 MW) was installed during 2010, bring- built the first concentrated-solar plant, which entered into ing the global total to 1095 MW. Spain added 400 MW operation in Sant'Ilario, near Genoa, Italy in 1968. This in 2010, taking the global lead with a total of 632 MW, plant had the architecture of today’s concentrated-solar while the US ended the year with 509 MW after adding plants with a solar receiver in the center of a field of solar 78 MW, including two fossil–CSP hybrid plants.[4] The collectors. The plant was able to produce 1 MW with su- Middle East is also ramping up their plans to install CSP perheated steam at 100 bar and 500 °C.[12] The 10 MW based projects and as a part of that Plan, Shams-I the Solar One power tower was developed in Southern Cali-

1 2 2 CURRENT TECHNOLOGY fornia in 1981, but the parabolic-trough technology of the nearby Solar Energy Generating Systems (SEGS), begun in 1984, was more workable. The 354 MW SEGS is still the largest solar power plant in the world, and will remain so until the 390 MW Ivanpah power tower project comes online.

2 Current technology

CSP is used to produce electricity (sometimes called so- lar thermoelectricity, usually generated through steam). Concentrated-solar technology systems use mirrors or lenses with tracking systems to focus a large area of sun- light onto a small area. The concentrated light is then Parabolic trough at a plant near Harper Lake, California used as heat or as a heat source for a conventional power plant (solar thermoelectricity). The solar concentrators used in CSP systems can often also be used to provide industrial process heating or cooling, such as in solar air- mercial parabolic trough plant are representative, along- conditioning. side with Plataforma Solar de Almería's SSPS-DCS test facilities in Spain.[20] Concentrating technologies exist in five common forms, namely parabolic trough, enclosed trough, dish Stir- lings, concentrating linear Fresnel reflector, and solar [13] power tower. Although simple, these solar concen- 2.1.1 Enclosed trough trators are quite far from the theoretical maximum concentration.[14][15] For example, the parabolic-trough concentration gives about 1/3 of the theoretical maxi- Enclosed trough systems are used to produce process mum for the design acceptance angle, that is, for the same heat. The design encapsulates the solar thermal system overall tolerances for the system. Approaching the theo- within a greenhouse-like glasshouse. The glasshouse cre- retical maximum may be achieved by using more elabo- ates a protected environment to withstand the elements rate concentrators based on nonimaging optics.[16] that can negatively impact reliability and efficiency of the solar thermal system.[21] Lightweight curved solar- Different types of concentrators produce different peak reflecting mirrors are suspended from the ceiling of the temperatures and correspondingly varying thermody- glasshouse by wires. A single-axis tracking system posi- namic efficiencies, due to differences in the way that they tions the mirrors to retrieve the optimal amount of sun- track the sun and focus light. New innovations in CSP light. The mirrors concentrate the sunlight and focus it on technology are leading systems to become more and more a network of stationary steel pipes, also suspended from [17] cost-effective. the glasshouse structure.[22] Water is carried throughout the length of the pipe, which is boiled to generate steam when intense solar radiation is applied. Sheltering the 2.1 Parabolic trough mirrors from the wind allows them to achieve higher tem- perature rates and prevents dust from building up on the Main article: Parabolic trough mirrors.[21]

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 di- 2.2 Fresnel reflectors rectly above the middle of the parabolic mirror and filled with a working fluid. The reflector follows the sun dur- ing the daylight hours by tracking along a single axis. A Main article: Compact Linear Fresnel Reflector working fluid (e.g. molten salt[18]) is heated to 150–350 °C (423–623 K (302–662 °F)) as it flows through the re- Fresnel reflectors are made of many thin, flat mirror strips ceiver and is then used as a heat source for a power gener- to concentrate sunlight onto tubes through which working ation system.[19] Trough systems are the most developed fluid is pumped. Flat mirrors allow more reflective sur- CSP technology. The Solar Energy Generating Systems face in the same amount of space as a parabolic reflector, (SEGS) plants in California, the world’s first commercial thus capturing more of the available sunlight, and they are parabolic trough plants, Acciona’s Nevada Solar One near much cheaper than parabolic reflectors. Fresnel reflectors Boulder City, Nevada, and Andasol, Europe’s first com- can be used in various size CSPs.[23][24] 3

but they offer higher efficiency and better energy stor- age capability. The Solar Two in Daggett, California and the CESA-1 in Plataforma Solar de Almeria Almeria, Spain, are the most representative demonstration plants. The Planta Solar 10 (PS10) in Sanlucar la Mayor, Spain, is the first commercial utility-scale solar power tower in the world. eSolar's 5 MW Sierra SunTower, located in Lancaster, California, is the only CSP tower facility op- erating in North America. The National Solar Thermal Test Facility, NSTTF located in Albuquerque, NM, is an experimental solar thermal test facility with a heliostat field capable of producing 6 MW.

3 Deployment around the world A dish Stirling Main articles: List of solar thermal power stations and Solar power by country 2.3 Dish Stirling 1,000 2,000 Main article: Dish Stirling 3,000 4,000 A dish Stirling or dish engine system consists of a stand- 1984 alone parabolic reflector that concentrates light onto a re- 1990 ceiver positioned at the reflector’s focal point. The reflec- 1995 tor tracks the Sun along two axes. The working fluid in 2000 the receiver is heated to 250–700 °C (523–973 K (482– 2005 1,292 °F)) and then used by a Stirling engine to gener- 2010 ate power.[19] Parabolic-dish systems provide high solar- Worldwide CSP capacity since 1984 in MW to-electric efficiency (between 31% and 32%), and their modular nature provides scalability. The Stirling Energy The commercial deployment of CSP plants started by Systems (SES), United Sun Systems (USS) and Science 1984 in the US with the SEGS plants until 1990 when Applications International Corporation (SAIC) dishes at the last SEGS plant was completed. From 1991 to 2005 UNLV, and Australian National University's Big Dish in no CSP plants were built anywhere in the world. Canberra, Australia are representative of this technology. As of 2008, The world record for solar to electric effi- In 2013, worldwide installed capacity increased by 36 ciency was set at 31.25% by SES dishes at the National percent or nearly 0.9 gigawatt to more than 3.4 GW. Solar Thermal Test Facility (NSTTF)[25] . The SES in- Spain and the United States remained the global leaders, stallation in Maricopa, Phoenix was the largest Stirling while the number of countries with installed CSP were Dish power installation in the world until it was sold to growing. There is a notable trend towards developing United Sun Systems. Subsequently, larger parts of the countries and regions with high solar radiation. Global installation have been moved to China as part of the huge installed CSP-capacity has increased nearly tenfold since energy demand. 2004 and grew at an average of 50 percent per year during the last five years.[26]:51

2.4 Solar power tower 4 Efficiency Main article: Solar power tower The conversion efficiency η of the incident solar radiation A solar power tower consists of an array of dual-axis into mechanical work − without considering the ultimate tracking reflectors (heliostats) that concentrate sunlight conversion step into electricity by a power generator − de- on a central receiver atop a tower; the receiver contains a pends on the thermal radiation properties of the solar re- fluid deposit, which can consist of sea water. The working ceiver and on the heat engine (e.g. steam turbine). Solar fluid in the receiver is heated to 500–1000 °C (773–1,273 irradiation is first converted into heat by the solar receiver K (932–1,832 °F)) and then used as a heat source for with the efficiency ηReceiver and subsequently the heat is a power generation or energy storage system.[19] Power- converted into work by the heat engine with the efficiency [29][30] tower development is less advanced than trough systems, ηCarnot , using Carnot’s principle. For a solar re- 4 5 COSTS ceiver providing a heat source at temperature TH and a The graph shows that the overall efficiency does not in- heat sink at room temperature T°, the overall conversion crease steadily with the receiver’s temperature. Although efficiency can be calculated as follows: the heat engine’s efficiency (Carnot) increases with higher temperature, the receiver’s efficiency does not. On the contrary, the receiver’s efficiency is decreasing, as the

η = ηReceiver · ηCarnot amount of energy it cannot absorb (Qₒ) grows by the fourth power as a function of temperature. Hence, there T 0 η = 1 − is a maximum reachable temperature. When the receiver Carnot T H efficiency( is null) (blue curve on the figure below), Tₐₓ is: Q − Q IC 0.25 absorbed lost Tmax = σ ηReceiver = Qsolar There is a temperature Tₒ for which the efficiency is maximum, i.e. when the efficiency derivative relative to where Q , Q , Q are solar absorbed lost the receiver temperature is null: respectively the incoming solar flux and the fluxes absorbed and lost by the system solar receiver. dη (Topt) = 0 For a solar flux I (e.g. I = 1000 W/m2) concentrated C dTH times with an efficiency ηOptics on the system solar re- Consequently, this leads us to the following equation: ceiver with a collecting area A and an absorptivity α :

T 0IC T 5 − (0.75T 0)T 4 − = 0 Qsolar = ηOpticsICA opt opt 4σ

Qabsorbed = αQsolar Solving this equation numerically allows us to obtain the For simplicity’s sake, one can assume that the losses are optimum process temperature according to the solar con- only radiative ones (a fair assumption for high tempera- centration ratio C (red curve on the figure below) tures), thus for a reradiating area A and an emissivity ϵ applying the Stefan-Boltzmann law yields:

4 Qlost = AϵσTH Simplifying these equations by considering perfect optics ( ηOptics = 1), collecting and reradiating areas equal and maximum absorptivity and emissivity ( α = 1, ϵ = 1) then substituting in the first equation gives

( ) ( ) σT 4 T 0 η = 1 − H · 1 − IC TH 5 Costs

As of 9 September 2009, the cost of building a CSP sta- tion was typically about US$2.50 to $4 per watt,[31] while the fuel (the sun’s radiation) is free. Thus a 250 MW CSP station would have cost $600–1000 million to build. That works out to $0.12 to 0.18 USD/kWh.[31] New CSP sta- tions may be economically competitive with fossil fuels. Nathaniel Bullard, a solar analyst at Bloomberg New En- ergy Finance, has calculated that the cost of electricity at the Ivanpah Solar Power Facility, a project under con- struction in Southern California, will be lower than that from photovoltaic power and about the same as that from natural gas.[32] However, in November 2011, Google announced that they would not invest further in CSP projects due to the rapid price decline of photovoltaics. 5

Google invested US$168 million on BrightSource.[33][34] 7 Future IRENA has published on June 2012 a series of studies titled: “Renewable Energy Cost Analysis”. The CSP A study done by Greenpeace International, the Euro- study shows the cost of both building and operation of pean Solar Thermal Electricity Association, and the CSP plants. Costs are expected to decrease, but there are International Energy Agency's SolarPACES group inves- insufficient installations to clearly establish the learning tigated the potential and future of concentrated solar curve. As of March 2012, there were 1.9 GW of CSP power. The study found that concentrated solar power [35] installed, with 1.8 GW of that being parabolic trough. could account for up to 25% of the world’s energy needs by 2050. The increase in investment would be from 2 billion euros worldwide to 92.5 billion euros in that time period.[41] Spain is the leader in concentrated so- 6 Incentives lar power technology, with more than 50 government- approved projects in the works. Also, it exports its tech- 6.1 Spain nology, further increasing the technology’s stake in en- ergy worldwide. Because the technology works best with Solar-thermal electricity generation is eligible for feed-in areas of high insolation (solar radiation), experts predict tariff payments (art. 2 RD 661/2007), if the system ca- the biggest growth in places like Africa, Mexico, and the pacity does not exceed the following limits: Systems reg- southwest United States. It indicates that the thermal istered in the register of systems prior to 29 September storage systems based in nitrates (calcium, potassium, 2008: 500 MW for solar-thermal systems. Systems regis- sodium,...) will make the CSP plants more and more tered after 29 September 2008 (PV only). The capacity profitable. The study examined three different outcomes limits for the different system types are re-defined dur- for this technology: no increases in CSP technology, in- ing the review of the application conditions every quarter vestment continuing as it has been in Spain and the US, (art. 5 RD 1578/2008, Annex III RD 1578/2008). Prior and finally the true potential of CSP without any barriers to the end of an application period, the market caps spec- on its growth. The findings of the third part are shown in ified for each system type are published on the website of the table below: the Ministry of Industry, Tourism and Trade (art. 5 RD Finally, the study acknowledged how technology for CSP 1578/2008).[36] was improving and how this would result in a drastic price Since 27 January 2012, Spain has halted acceptance of decrease by 2050. It predicted a drop from the current [41] new projects for the feed-in-tariff.[37][38] Projects cur- range of €0.23–0.15/kwh to €0.14–0.10/kwh. Re- rently accepted are not affected, except that a 6% tax on cently the EU has begun to look into developing a €400 feed-in-tariffs has been adopted, effectively reducing the billion ($774 billion) network of solar power plants based feed-in-tariff.[39] in the Sahara region using CSP technology known as Desertec, to create “a new carbon-free network linking Europe, the Middle East and North Africa”. The plan is backed mainly by German industrialists and predicts pro- 6.2 Australia duction of 15% of Europe’s power by 2050. Morocco is a major partner in Desertec and as it has barely 1% of the At the federal level, under the Large-scale Renewable En- electricity consumption of the EU, it will produce more ergy Target (LRET), in operation under the Renewable than enough energy for the entire country with a large en- Energy Electricity Act 2000 (Cth), large scale solar ther- ergy surplus to deliver to Europe.[42] mal electricity generation from accredited RET power Algeria has the biggest area of desert, and private stations may be entitled to create large-scale generation [42] certificates (LGCs). These certificates can then be sold Algerian firm Cevital has signed up for Desertec. and transferred to liable entities (usually electricity retail- With its wide desert (the highest CSP potential in the ers) to meet their obligations under this tradeable certifi- Mediterranean and Middle East regions ~ about 170 cates scheme. However as this legislation is technology TWh/year) and its strategic geographical location near neutral in its operation, it tends to favour more established Europe Algeria is one of the key countries to ensure the RE technologies with a lower levelised cost of generation, success of Desertec project. Moreover, with the abun- such as large scale onshore wind, rather than solar ther- dant natural-gas reserve in the Algerian desert, this will mal and CSP.[40] At State level, renewable energy feed-in strengthen the technical potential of Algeria in acquir- laws typically are capped by maximum generation capac- ing Solar-Gas Hybrid Power Plants for 24-hour electric- ity in kWp, and are open only to micro or medium scale ity generation. generation and in a number of instances are only open Other organizations expect CSP to cost $0.06(US)/kWh to solar PV (photovoltaic) generation. This means that by 2015 due to efficiency improvements and mass pro- larger scale CSP projects would not be eligible for pay- duction of equipment.[43] That would make CSP as cheap ment for feed-in incentives in many of the State and Ter- as conventional power. Investors such as venture capital- ritory jurisdictions. ist Vinod Khosla expect CSP to continuously reduce costs 6 11 REFERENCES and actually be cheaper than coal power after 2015. On 9 September 2009, Bill Weihl, Google.org's green- energy spokesperson said that the firm was conducting research on the heliostat mirrors and gas turbine technol- ogy, which he expects will drop the cost of solar thermal electric power to less than $0.05/kWh in 2 or 3 years.[31] In 2009, scientists at the National Renewable Energy Laboratory (NREL) and SkyFuel teamed to develop large curved sheets of metal that have the potential to be 30% less expensive than today’s best collectors of concentrated solar power by replacing glass-based models with a silver polymer sheet that has the same performance as the heavy glass mirrors, but at much lower cost and weight. It also is much easier to deploy and install. The glossy film uses Deceased Warbler burned mid-air by solar thermal power plant several layers of polymers, with an inner layer of pure silver. Telescope designer Roger Angel (Univ. of Arizona) has 10 See also turned his attention to CPV, and is a partner in a company called Rehnu. Angel utilizes a spherical concentrating • List of solar thermal power stations lens with large-telescope technologies, but much cheaper • Concentrated photovoltaics (CPV) materials and mechanisms, to create efficient systems.[44] • Copper in concentrating solar thermal power facili- ties 8 Very large scale solar power • Clean Technology Fund plants • Desertec • Luminescent solar concentrator There are several proposals for gigawatt size, very large • scale solar power plants. They include the Euro- Photovoltaic thermal hybrid solar collector#PV/T Mediterranean Desertec proposal, Project Helios in concentrator (CPVT) (CPVT) Greece (10 gigawatt), and Ordos (2 gigawatt) in China. • Salt evaporation pond A 2003 study concluded that the world could generate 2,357,840 TWh each year from very large scale solar • Sandia National Laboratory power plants using 1% of each of the world’s deserts. Total consumption worldwide was 15,223 TWh/year[45] • SolarPACES (in 2003). The gigawatt size projects are arrays of single • plants. The largest single plant in operation is 80 MW Solar air conditioning (SEGS VIII and SEGS IX) and the largest single plant • Solar lighting in construction is 370 MW (Ivanpah Solar). In 2012, the BLM made available 97,921,069 acres of land in the • Solar thermal collector southwestern United States for solar projects, enough for between 10,000 and 20,000 gigawatts (GW).[46] • Solar hot water • Thermochemical cycle

• Thermoelectricity 9 Effect on wildlife • Total Spectrum Solar Concentrator

It has been noted that insects can be attracted to the bright light caused by concentrated solar technology, and as a re- 11 References sult birds that hunt them can be killed (burned) if the birds fly near the point where light is being focused onto. This [1] “Sunshine to Petrol”. Sandia National Laboratories. Re- can also affect raptors who hunt the birds.[47][48][49][50][51] trieved 11 April 2013. However, the number of bird deaths is far lower than the hundreds of millions to billions that die annually from col- [2] “Integrated Solar Thermochemical Reaction System”. lisions with windows, vehicles, and power lines. [52] U.S. Department of Energy. Retrieved 11 April 2013. 7

[3] Matthew L. Wald (10 April 2013). “New Solar Process [22] Helman, Christopher, “Oil from the sun”, “Forbes”, 25 Gets More Out of Natural Gas”. The New York Times. April 2011 Retrieved 11 April 2013. [23] Compact CLFR. Physics.usyd.edu.au (12 June 2002). [4] Janet L. Sawin and Eric Martinot (29 September 2011). Retrieved on 22 April 2013. “Renewables Bounced Back in 2010, Finds REN21 Global Report”. Renewable Energy World. [24] Ausra’s Compact Linear Fresnel Reflector (CLFR) and Lower Temperature Approach. ese.iitb.ac.in [5] Largest CSP Project in the World Inaugurated in Abu Dhabi – Renew India Campaign – solar photovoltaic, In- [25] Sandia, Stirling Energy Systems set new world record for dian Solar News, Indian Wind News, Indian Wind Mar- solar-to-grid conversion efficienc. Share.sandia.gov (12 ket. Renewindians.com (18 March 2013). Retrieved on February 2008). Retrieved on 22 April 2013. 22 April 2013. [26] REN21 (2014). “Renewables 2014: Global Status Re- [6] Thomas W. Africa (1975). “Archimedes through the port”. Archived from the original on 4 September 2014. Looking Glass”. The Classical World 68 (5): 305–308. [27] CSP Facts & Figures. Csp-world.com. Retrieved on 22 doi:10.2307/4348211. JSTOR 4348211. April 2013. [7] Ken Butti, John Perlin (1980) A Golden Thread: 2500 [28] Concentrating Solar Power. irena.org, p. 11. Years of Solar Architecture and Technology, Cheshire Books, pp. 66–100, ISBN 0442240058. [29] E. A. Fletcher (2001). “Solar thermal processing: A re- view”. Journal of Solar Energy Engineering 123 (2): 63. [8] CM Meyer. From troughs to triumph: SEGS and gas. doi:10.1115/1.1349552. Eepublishers.co.za. Retrieved on 22 April 2013. [30] Aldo Steinfeld & Robert Palumbo (2001). “Solar Ther- [9] Cutler J. Cleveland (23 August 2008). Shuman, Frank. mochemical Process Technology”. Encyclopedia of Phys- Encyclopedia of Earth. ical Science & Technology, R.A. Meyers Ed. (Academic [10] Paul Collins (Spring 2002) The Beautiful Possibility. Press) 15: 237–256. Cabinet Magazine, Issue 6. [31] Poornima Gupta and Laura Isensee (11 September 2009). [11] “A New Invention To Harness The Sun” Popular Science, Carol Bishopric, ed. “Google Plans New Mirror For November 1929 Cheaper Solar Power”. Global Climate and Alter- native Energy Summit. San Francisco: Reuters & [12] Ken Butti, John Perlin (1980) A Golden Thread: 2500 businessworld.in. Years of Solar Architecture and Technology, Cheshire Books, p. 68, ISBN 0442240058. [32] Robert Glennon and Andrew M. Reeves (2010). “Solar Energy’s Cloudy Future”. Arizona Journal of Environ- [13] Types of solar thermal CSP plants. Tomkon- mental Law & Policy 91: 106. rad.wordpress.com. Retrieved on 22 April 2013. [33] Google cans concentrated solar power project, Reve, 24 [14] Julio Chaves (2008) Introduction to Nonimaging Optics, November 2011. CRC Press, ISBN 978-1420054293 [34] Google Renewable Energy Cheaper than Coal (RE

[21] Deloitte Touche Tohmatsu Ltd, “Energy & Resources Pre- [39] Spain introduces 6% energy tax. Evwind.es (14 Septem- dictions 2012”, 2 November 2011 ber 2012). Retrieved on 22 April 2013. 8 12 EXTERNAL LINKS

[40] A Dangerous Obsession with Least Cost? Climate Change, Renewable Energy Law and Emissions Trading Prest, J. (2009) in Climate Change Law: Comparative, Contractual and Regulatory Considerations, W. Gumley & T. Daya-Winterbottom (eds.) Lawbook Company, ISBN 0455226342

[41] Concentrated solar power could generate 'quarter of world’s energy' Guardian

[42] Tom Pfeiffer (23 August 2009) Europe’s Saharan power plan: miracle or mirage? Reuters

[43] CSP and photovoltaic solar power, Reuters (23 August 2009).

[44] “Video: Concentrating photovoltaics inspired by telescope design”. SPIE Newsroom. 2011. doi:10.1117/2.3201107.02.

[45] A Study of Very Large Solar Desert Systems with the Re- quirements and Benefits to those Nations Having High So- lar Irradiation Potential. geni.org.

[46] Solar Resource Data and Maps. Solareis.anl.gov. Re- trieved on 22 April 2013.

[47] http://www.nbcnews.com/science/environment/ burned-birds-become-new-environmental-victims-energy-quest-n184426

[48] http://www.esquire.com/blogs/news/ solar-plant-dead-birds-081914

[49] http://www.foxnews.com/science/2014/08/18/ california-weighing-bird-deaths-from-concentrated-solar-plants-as-it-considers/

[50] http://bigstory.ap.org/article/ emerging-solar-plants-scorch-birds-mid-air

[51] http://spectrum.ieee.org/energywise/green-tech/solar/ ivanpah-solar-plant-turns-birds-into-smoke-streamers

[52] http://www.west-inc.com/reports/avian_collisions.pdf

12 External links

• Concentrating Solar Power Utility • United Sun Systems

• NREL Concentrating Solar Power Program • Plataforma Solar de Almeria, CSP research center

• ISFOC (Institute of Concentrating Photovoltaic Systems)

• Understanding Solar Concentrators – Technical Pa- per by George M. Kaplan

• Mirrors and Optics for Solar Energy – Technical ar- ticle on mirrors and optics for concentrating solar by Drs. Robert Molenaar in Solar Novus Today. 9

13 Text and image sources, contributors, and licenses

13.1 Text

• Concentrated solar power Source: http://en.wikipedia.org/wiki/Concentrated%20solar%20power?oldid=639085979 Contributors: Rmhermen, Jdpipe, Fred Bauder, Mdupont, MichaelJanich, Mac, Glenn, Andres, Twang, Sunray, Phanly, Wizzy, Micru, Khalid hassani, Isidore, Pbannister, Rich Farmbrough, Vsmith, Nabla, Giraffedata, Alansohn, Ahruman, Wtshymanski, Djsasso, Blaxthos, Mindmatrix, WadeSimMiser, Vegaswikian, Payo, Srleffler, Bgwhite, Wavelength, Mrienstra, NeilenMarais, Tigalch, Sirlark, DrHok, Arthur Rubin, Reyk, Sbyrnes321, SmackBot, Lawrencekhoo, KVDP, DLH, IstvanWolf, Thumperward, Victorgrigas, ABACA, A. B., Fotoguzzi, Ra- tel, Davipo, OmicronSSD, Fangfufu, P199, Mfield, HelloAnnyong, Chris55, Myasuda, Cydebot, Alaibot, Electron9, Dawnseeker2000, TimVickers, Andrew Swallow, TikiTDO, Parsecboy, Yahp, Beagel, Charlenelieu, Cander0000, CommonsDelinker, NightFalcon90909, Acalamari, M-le-mot-dit, DadaNeem, Whitethunder79, Pdcook, Johnfos, ICE77, Bkengland, Rdsherwood, Tri400, Aterk, E8, Mal- colmxl5, Jojalozzo, Nopetro, OKBot, Cngoulimis, ImageRemovalBot, ClueBot, The Thing That Should Not Be, DumZiBoT, Damien- buie, Quidproquo2004, Mortense, Lars9e, 84user, Rehman, Bultro, Apteva, Yobot, Bunnyhop11, Anlai neu, TheThomas, AnomieBOT, A More Perfect Onion, Materialscientist, RokerHRO, GB fan, LilHelpa, Nnivi, DataWraith, Jose ac, Martinella, Jeriee, Ruy Pugliesi, Rbentley1a, Susisuess, Jakethequake, Mathonius, Entechsolar1, Solarenola, Unused0010, FrescoBot, SolarGuru, Mbudzi, Richbham, Xk- laim, Chenopodiaceous, Arice6767, Elekhh, Sunsprite, 775852O, Bneeland1, George Plhak, Tbhotch, Jfmantis, BaSH PR0MPT, TGCP, Paolotvl, Domesticenginerd, Enviromet, SolarJonathan, Lent1999, BardotD, Ὁ οἶστρος, H3llBot, Msrt10, Hamiltha, Rangoon11, Marc- Chambon, Corb555, Wintergrove, Hueck00u, JonRichfield, Miguel.baillon, Rememberway, ClueBot NG, Hasan Tushar, Alcauza, Otile- unam, FlavienM, Joe Greentrees, Delusion23, Jose Manuel Buenavida, Mmarre, Jcc2011, Philua, Geometry001, Trinder67, Frohfroh, Northamerica1000, Mark Arsten, NivZ, Kathy.mckenzie93, Jezzabub, Mepredator, Hillbillyholiday, Joeinwiki, Antoine Poliakov, Rfass- bind, Lemnaminor, Rahulprabhurr, Larsvalentin, Solar Generator Reviews, Btmaxted, Ovelinha, Ender000, Samalmaairgy and Anonymous: 156

13.2 Images

• File:Crystal_energy.svg Source: http://upload.wikimedia.org/wikipedia/commons/1/14/Crystal_energy.svg License: LGPL Contributors: Own work conversion of Image:Crystal_128_energy.png Original artist: Dhatfield • File:Flag_of_Algeria.svg Source: http://upload.wikimedia.org/wikipedia/commons/7/77/Flag_of_Algeria.svg License: Public domain Contributors: SVG implementation of the 63-145 Algerian law "on Characteristics of the Algerian national emblem" ("Caractéristiques du Drapeau Algérien", in English). Original artist: This graphic was originaly drawn by User:SKopp. • File:Flag_of_Australia.svg Source: http://upload.wikimedia.org/wikipedia/en/b/b9/Flag_of_Australia.svg License: Public domain Con- tributors: ? Original artist: ? • File:Flag_of_Egypt.svg Source: http://upload.wikimedia.org/wikipedia/commons/f/fe/Flag_of_Egypt.svg License: CC0 Contributors: From the Open Clip Art website. Original artist: Open Clip Art • File:Flag_of_India.svg Source: http://upload.wikimedia.org/wikipedia/en/4/41/Flag_of_India.svg License: Public domain Contributors: ? Original artist: ? • File:Flag_of_Morocco.svg Source: http://upload.wikimedia.org/wikipedia/commons/2/2c/Flag_of_Morocco.svg License: Public domain Contributors: adala.justice.gov.ma (Ar) Original artist: Denelson83, Zscout370 • File:Flag_of_Spain.svg Source: http://upload.wikimedia.org/wikipedia/en/9/9a/Flag_of_Spain.svg License: ? Contributors: ? Original artist: ? • File:Flag_of_Thailand.svg Source: http://upload.wikimedia.org/wikipedia/commons/a/a9/Flag_of_Thailand.svg License: Public domain Contributors: Own work Original artist: Zscout370 • File:Flag_of_the_People’{}s_Republic_of_China.svg Source: http://upload.wikimedia.org/wikipedia/commons/f/fa/Flag_of_the_ People%27s_Republic_of_China.svg License: Public domain Contributors: Own work, http://www.protocol.gov.hk/flags/eng/n_flag/ design.html Original artist: Drawn by User:SKopp, redrawn by User:Denelson83 and User:Zscout370 • File:Flag_of_the_United_Arab_Emirates.svg Source: http://upload.wikimedia.org/wikipedia/commons/c/cb/Flag_of_the_United_ Arab_Emirates.svg License: Public domain Contributors: ? Original artist: ? • File:Flag_of_the_United_States.svg Source: http://upload.wikimedia.org/wikipedia/en/a/a4/Flag_of_the_United_States.svg License: ? Contributors: ? Original artist: ? • File:Folder_Hexagonal_Icon.svg Source: http://upload.wikimedia.org/wikipedia/en/4/48/Folder_Hexagonal_Icon.svg License: Cc-by- sa-3.0 Contributors: ? Original artist: ? • File:PS10_solar_power_tower.jpg Source: http://upload.wikimedia.org/wikipedia/commons/e/eb/PS10_solar_power_tower.jpg Li- cense: CC BY 2.0 Contributors: SOLUCAR PS10 Original artist: afloresm • File:Parabolic_trough_at_Harper_Lake_in_California.jpg Source: http://upload.wikimedia.org/wikipedia/commons/a/a8/ Parabolic_trough_at_Harper_Lake_in_California.jpg License: CC BY-SA 3.0 Contributors: Own work Original artist: Z22 • File:Portal-puzzle.svg Source: http://upload.wikimedia.org/wikipedia/en/f/fd/Portal-puzzle.svg License: Public domain Contributors: ? Original artist: ? • File:SolarConcentration_max_opt_temperatures.png Source: http://upload.wikimedia.org/wikipedia/commons/f/ff/ SolarConcentration_max_opt_temperatures.png License: CC BY-SA 3.0 Contributors: Own work Original artist: http: //en.wikipedia.org/wiki/User:MarcChambon • File:SolarStirlingEngine.jpg Source: http://upload.wikimedia.org/wikipedia/commons/5/59/SolarStirlingEngine.jpg License: Public domain Contributors: Transferred from en.wikipedia Original artist: Original uploader was Skyemoor at en.wikipedia • File:Solar_Plant_kl.jpg Source: http://upload.wikimedia.org/wikipedia/commons/6/63/Solar_Plant_kl.jpg License: Public domain Con- tributors: http://www.ca.blm.gov/cdd/alternative_energy.html Original artist: USA.Gov - BLM - BUREAU OF LAND MANAGEMENT 10 13 TEXT AND IMAGE SOURCES, CONTRIBUTORS, AND LICENSES

• File:Solar_concentration_efficiency.png Source: http://upload.wikimedia.org/wikipedia/commons/4/48/Solar_concentration_ efficiency.png License: CC BY-SA 3.0 Contributors: ? Original artist: ? • File:Sustainable_development.svg Source: http://upload.wikimedia.org/wikipedia/commons/7/70/Sustainable_development.svg Li- cense: CC-BY-SA-3.0 Contributors: • Inspired from Developpement durable.jpg Original artist: • original: Johann Dréo (talk · contribs) • File:Symbol_list_class.svg Source: http://upload.wikimedia.org/wikipedia/en/d/db/Symbol_list_class.svg License: Public domain Con- tributors: ? Original artist: ? • File:Warbler_burned_mid-air_by_solar_thermal_power_plant.jpg Source: http://upload.wikimedia.org/wikipedia/commons/b/be/ Warbler_burned_mid-air_by_solar_thermal_power_plant.jpg License: Public domain Contributors: • http://bigstory.ap.org/article/emerging-solar-plants-scorch-birds-mid-air Original artist: U.S. Fish and Wildlife Service • File:Wind-turbine-icon.svg Source: http://upload.wikimedia.org/wikipedia/commons/a/ad/Wind-turbine-icon.svg License: GFDL Con- tributors: Own work Original artist: Lukipuk

13.3 Content license

• Creative Commons Attribution-Share Alike 3.0