CSP Technology US market Poised for growth Utilities needing to meet Renewable Portfolio Standards sun’s energy on a receiver that generates steam and turns a generator for electricity production – have (RPS) in 27 US states, federal support for solar energy been in operation in the US for more than 25 years. However, no new commercial plants were built be­ expected in the near future and the new administration’s tween 1991 and 2007. With such a long history in the sense of urgency about combating climate change revive the US, why are companies suddenly proposing so much CSP? “Firstly, there is a profound understanding from CSP industry in the US. Americans that our dependence on fossil fuels, specif­ ically imported, is a national security threat and also t least 15 companies have proposed 25 con­ creating tremendous environmental damage”, ex­ centrating (CSP) projects in the plains Keely Wachs, Senior Director of Communica­ AUS, while only three CSP plants are now on­ tions, BrightSource Energy, . In addition, the line. Just as important, many of the companies have US government is stepping up to support renewable contracts with utilities already in place. The CSP com­ energy as a means of stabilizing the economy and cre­ panies that already have signed power purchase ating jobs. “Fossil fuels, in regards to price, are vola­ ­agreements with utilities have proposed a combined tile, which makes markets unpredictable. Markets 5 GW of solar projects, says Mark Mehos, Principle need stability to flourish”, Wachs says and adds, “re­ Programme Manager for CSP at the National Renew­ newable energy could also be a great source of new able Energy Laboratory (NREL), Washington D.C. jobs and earning to boost the economy.” In spite of the growth, the CSP industry needs to For the first time in US history, the President and find ways to lower costs and deliver reliable power, his administration understand the complex issues experts say. Companies are addressing the challenge surrounding energy and how renewable energy fits by using new technology, increasing plant efficiency, into it, says Wachs. “With President Obama you are reducing the amount of material used, cutting assem­ seeing a sense of urgency which we have never seen bly time, and standardizing components. before. He has amassed a team that really under­ CSP plants – which use mirrors to concentrate the stands how to administer new technology and neces­

Power tower test field of BrightSource Energy in the Negev Desert, . The company is actively developing more than 4 GW of solar power pro- jects in Southwestern US. Photo: Brightsource

74 Sun & Wind Energy 6/2009 sary legislation.” In addition to the federal govern­ ment, state efforts are also propelling CSP growth. Many states have adopted ambitious Renewable Port­ folio Standards (RPS), which require utilities to pur­ chase a certain percentage of their energy from re­ newable sources by a set date. “There are now 27 states with RPS and they are all voluntary”, says Jim Shandalov, Vice President of Business Development, eSolar, California. “The federal level also wants to set a national standard.” Utilities see CSP as a means of meeting RPS be­ cause it can in many circumstances provide cost-­ effective utility scale power. “With California’s RFP (Request for Proposals) standard, large stand-alone solar projects are really where the need is”, says ­Thomas Barnett, Executive Vice President, Inland ­Energy, California. In order to meet RPS in California, the state’s utilities must install 800 MW of CSP every year from now until 2020, explained Rainer Aringhoff, President of Solar Millenium, Germany. This is how eSolar’s 5 MW commercial much CSP is needed to stabilize the grid, he said at Utilities invest in different Sierra power tower plant in the Renewable Energy Technology Conference technologies Lancaster, California. Towers ­(RETECH) 2009, Las Vegas. To meet California’s ag­ are based on mass-manufactu- gressive RPS – which calls for 20 % renewable power In addition to using the trough technology in the red components and designed by 2010 – utilities are embracing CSP. For example, SEGS and Solar One plants, utilities are in­ for rapid construction, uniform Southern California Edison (SCE) recently signed an vesting in a variety of CSP technologies. They each modularity, and unlimited agreement with BrightSource Energy for 1,300 MW of have advantages and disadvantages. Most CSP plants scalability. Photo: eSolar CSP, making it the world’s largest solar power deal to – trough, tower and dish – concentrate the sun’s en­ date, reports Wachs. Construction on the first plant, ergy on a receiver to produce steam, turn a generator Ivanpah I, will begin later this year in California. The and produce power. plant will start producing power by the end of 2011, The most widespread type of CSP plant uses par­ he announced. Contracts of this size have been un­ abolic trough technology, which concentrates solar heard of in the US, Mehos says. energy with long, curved mirrors onto a receiver that runs the length of the trough. The receiver is filled End of a 17-year hiatus in CSP with water, or another solution, which gets heated and is used to boil water. The steam turns a conven­ The first US CSP installation and the largest in the tional steam-turbine generator to produce electricity. world – the Solar Energy Generating System (SEGS) – The advantage of the trough plant is its operating his­ consists of nine CSP plants built be­ tory, according to Mehos. “The other technologies tween 1984 and 1990 in the Mojave Desert, Califor­ are more theoretical than actual”, he says. nia. The SEGS plants have 354 MW of installed capac­ Unlike trough systems, the power tower CSP ity and have been delivering reliable power for more plant uses multiple mirrors to concentrate on a single than 25 years. Despite the success and reliability of receiver. Software controls thousands of mirrors that the SEGS plants, the US government neglected to track the sun, explains Wachs. “They reflect onto one support further development of CSP, Mehos laments. central receiver, a boiler, which sits on top of a European companies, on the other hand, have contin­ 300-foot tower.” The boiler converts the solar energy ued to improve CSP technology, led by Germany and directly to steam, which gets pumped into a turbine Spain, which supported renewable energy with and generates electricity at the tower, says Wachs. strong legislation. However, with the new Obama ad­ The tower technology achieves higher temperatures, ministration heavily supporting renewable energy, which increases operation efficiency, Mehos adds. many companies are now looking to the US as the Like small versions of the power tower, parabolic next big CSP player, says Mehos. “The next largest dish CSP plants use one curved mirror to focus ener­ market that Abengoa wishes to take part in is the US gy on the receiver. In a commercial plant, in order to Southwest”, announced Scott Frier, COO Abengoa generate enough energy to be commercially viable, Solar, Spain, at RETECH. developers must install multiple dishes. “Dish tech­ After a 17-year hiatus in CSP construction in the nology has the highest operating temperature and US, Acciona Solar, Spain in 2007 installed a 64-MW therefore the greatest efficiency”, remarks Mehos. trough plant, , Nevada. The plant However, dish technology does not allow for energy uses 2 % backup, a big reduction from 25 storage, he explains. % natural gas backup in the SEGS plants. 760 para­ Concentrating photovoltaics (CPV), where lenses bolic troughs cover 350 acres (1,42 km2), according or mirrors concentrate sunlight onto high-efficiency to a report by NREL. solar cells offers another option. Concentrating sun­

Sun & Wind Energy 6/2009 75 CSP Technology US market

Current CSP projects

Electricity Technology, Start of Heat transfer fluid, Efficiency Project name Developer Location Website of developer purchaser capacity operation temperature [%] Solar Energy Genera- BrightSource Energy Kramer Junction Southern between 1984 29.4 to http://www.brightsour- ting Systems (SEGS) (formerly Luz Indus- & Daggett, California trough, 354 MW thermo-oil, 400 °C and 1991 37.6 ceenergy.com/ I-IX tries) California Edison Boulder City, http://www.acciona-na. Nevada Solar One Acciona Nevada Energy trough, 64 MW 2007 thermo-oil, 391 °C 37.6 Nevada com/ Table 1: Despite the success and reliability of the SEGS plants, the US government neglected to support further development of CSP. With the construction of the Nevada Solar One plant, a 17-year hiatus in CSP construction in the US ended.

CSP projects under development and planned CSP projects

Start of Project name Developer Location Electricity purchaser Technology, capacity Website of developer operation Ivanpah, Cali- http://www.brightsourceenergy. Ivanpah BrightSource Pacific Gas & Electric tower, 300 MW 2011 fornia com/ Ivanpah, Cali- http://www.brightsourceenergy. Ivanpah BrightSource Southern California Edison tower, 100 MW 2011 fornia com/ Lancaster, Sierra plant eSolar Southern California Edison tower, 5 MW 2009 http://www.esolar.com/ California Kern County, tower, 105 MW & Gaskell Sun Tower (Phase I & II) eSolar Southern California Edison 2012 http://www.esolar.com/ California 140 MW Solana Plant Gila Bend, Arizona trough, 280 MW n/a http://www.abengoa.com Martin Next Generation Solar Florida Power & Light Martin County, Florida Power & Light Co. trough, 75 MW 2009 http://www.fpl.com/ Energy Center Co. Florida Palmdale, Palmdale Hybrid Gas-Solar Plant Inland Energy City of Palmdale trough, 50 MW 2013 http://www.inlandenergy.net California Victorville Hybrid Gas-Solar Victorville, Inland Energy City of Victorville trough, 50 MW 2010 http://www.inlandenergy.net Plant California Nye County, trough, 250 MW & http://www.solarmillennium. Nye County Project 1 & 2 Solar Millennium Nevada Energy 2014 Nevada 250 MW com Mojave Desert, Pacific Gas & Electric trough, 553 MW 2011 http://www.solel.com/ California Coalinga, trough, 53 MW & 53 San Joaquin Solar 1 & Solar 2 San Joaquin Solar, LLC Pacific Gas & Electric 2011 n/a California MW NextEra Energy Kern County, www.nexteraenergyresources. Beacon Solar Energy Project n/a trough, 250 MW 2011 Resources California com Harper Lake, LLC (Flo- Harper Lake, http://ww2.harperlakellc. Harper Lake Solar Plant n/a trough, 250 MW 2010 rida Light & Power) California com:8282/hl-ep/overview.html SES Solar One & Solar One Stirling Energy Victorville, dish-engine, 500 MW Southern California Edison n/a www.stirlingenergy.com Expansion Systems California & 350 MW SES Solar Two & Solar Two Stirling Energy Imperial County, dish-engine, 300 MW San Diego Gas & Electric n/a www.stirlingenergy.com Expansion Systems California & 600 MW Carrizo Plain, n/a Ausra Pacific Gas & Electric linear fresnel, 177 MW 2010 www.ausra.com California http://www.emcore.com/so- n/a Emcore Southwestern US SunPeak Power CPV, 200 MW 2011 lar_photovoltaics n/a Greenvolts Inc. Byron, Calirfornia Pacific Gas & Electric CPV, 2 MW 2009 http://www.greenvolts.com/ Planned CSP projects Southern California Edison, http://www.brightsourceenergy. n/a Bright Source Energy Southwestern US tower, 1,800 MW n/a Pacific Gas & Electric com/ eSolar/Sunpeak n/a Southwestern US n/a tower, 500 MW 2011 http://www.esolar.com Power

Table 2: Developers believe in light decreases the required cell area while increas­ over time”, reported Avi Brenmiller, President of Solel different technologies for con- ing efficiency. “High efficiency is beneficial when ­Energy, Israel, at RETECH. centrating solar power. Some land or rooftop space is constrained”, says Mehos. “Troughs are a good technology, but are limited count on the well experienced in efficiency and cost”, says Wachs. Hoping to achieve trough technology while others Tower or trough? higher efficiency, BrightSource Energy decided to de­ seek for higher efficiency by velop power towers, despite the risks involved with using tower and dish technol­ Some companies are choosing to develop newer newer technology. The tower converts water directly gies or concentrating photovol- and riskier technology, like the power tower, while to steam at the boiler, which increases efficiency. taics (CPV). others continue to develop reliable parabolic trough ­“Efficiency gains are up to thirty percent compared to technology. “You can improve efficiency two ways: troughs”, adds Wachs. “Troughs require curved you can use something completely new, or use an glass, which is very expensive and only produced by older technology and make small improvements on it two groups in the world.”

76 Sun & Wind Energy 6/2009 Like BrightSource, eSolar developed the power tower because it requires less land. “Troughs require six to eight acres per MW and only four acres for the tower”, says Shandalov. “We can pack mirrors tight­ ly, without leaving much space in between.” Solar de­ velopers often encounter problems obtaining land permits, which are some of the largest bottlenecks to CSP project development, according to Shandalov. Despite the efficiency gains and land-use bene­ fits of tower technology, Solel is sticking with reliable trough technology. “We continue to evolve the tech­ nology and now our collectors generate 50 % more energy than initial SEGS trough plants”, reported Avi Brenmiller, President of Solel, Israel, at RETECH. Be­ cause technology and performance are so well under­ stood, trough developers can focus on improving the receiver, the most critical component affecting effi­ ciency in CSP plants, explains Brenmiller. “We have manufactured 300,000 receivers, which are the key to improving efficiency.” Long tested and well-understood technology at­ tracts investors and loans, making it easier for com­ Potential viable CSP locations panies to get funding. “Banks understand what the reduced the cost of parabolic trough plants by 35 % in the Southwestern US. Many risks are for troughs, so it isn’t a risk for them”, said in its first plant design, according to Leitner. SkyFuel valleys in California, Arizona Scott Frier, COO of Abengoa Solar, Spain, at RETECH. decreased its manufacturing costs by reducing the and Nevada offer excellent con- In the long-term, developers will focus on improving raw materials needed to construct the trough support ditions for using CSP technolo- power tower technology. “The tower is the logical frame. “The Sky Trough is the largest module built to gies. Graphic: NREL place for solar technology to evolve because it has date, yet there is a lot less material in the space frame higher efficiency”, says Shandalov. than ever before and that is a big cost-saver”, adds Towers obtain high temperatures and pressures, Leitner. SkyFuel has found that its units are easier to which improves solar energy efficiency. “The holy transport and quicker to install if they use fewer ma­ grail in solar thermal production is high temperature terials. “There are forty percent fewer parts and thir­ and pressure”, Wachs points out. “The laws of phys­ ty percent less mass than Nevada Solar One – at the ics prevent troughs and other technologies to get to same performance – and two times the assembly those temperatures.” Towers currently operate speed.” around 550 °C and produce super-heated steam. SkyFuel, like Solel, develops and installs the en­ “The goal is to get to super-critical steam, or 650 °C, tire collector, which also reduces costs. “Integrating and beyond”, Wachs explains. all of the different parts together is the most chal­ CSP companies are producing clean power, re­ lenging part”, explained Brenmiller. Installation is gardless of the type of technology, said Brenmiller. easier, shorter, and more reliable when one company “Who really cares if it is a trough, tower, or dish”, he develops and installs all components of a plant, as asked. “Make it clean and make it cheap. The task of opposed to various companies each responsible for the industry is clear: make solar energy affordable different parts. Standardization of parts reduces and dependable, however possible.” transportation costs and cuts assembly time in half, said Leitner. “Standardization of the solar field will Reducing cost and become more important in the future for cost reduc­ increasing dependability tions and quick solar power integration”, he added. In addition to reducing costs, increasing the via­ For developers, the most effective method of reduc­ bility and dependability of CSP makes it easier for de­ ing cost is increasing operation efficiency. For exam­ velopers to attract utilities and get funding. “We be­ ple, SkyFuel has increased the efficiency and preci­ lieve people will be able to finance the projects be­ sion of the reflective surface. “They are now more re­ cause we integrate everything into one system and flective, accurate, never break and cost less”, sum­ ensure that it works”, said Brenmiller. marized Arnold Leitner, CEO and President of SkyFuel, California, at the RETECH conference. For high preci­ Dispatchable power sion, SkyFuel uses a mirror film that has 94 % reflec­ generation through storage tivity, is very thin, and uses little material. In addition to reducing cost through operation ef­ One way to boost CSP’s dependability is to add ener­ ficiency, solar developers are reducing costs during gy storage capacity. “Storage allows plant operators manufacturing, transportation, and installation.“With to shift energy and store it for peak power”, points new materials and designs you can have dramatic out Aringhoff. Solar power, without storage, only gen­ cost reductions”, said Leitner. For example, SkyFuel erates power when the sun is shining. A backup sys­

Sun & Wind Energy 6/2009 77 CSP Technology US market

tem – storage or another energy source – is neces­ vide as much power. During the summer, when natu­ sary for fluctuations in energy production throughout ral gas efficiency drops, solar panels operate at their the day and night, says Barnett. “Solar energy can maximum capacity. “This is a good mix”, says Bar­ help with peak energy and we offer solar thermal nett. Combining dispatchable forms of renewable en­ storage to level out irregularities in peak loads”, adds ergy with fossil fuels prevents the utilities from oper­ Frier. Utilities need dispatchable forms of energy, ating their oldest and dirtiest plants, which are only which can be met through storage, remarks Leitner. needed during peak power. “So this is very reliable “Parabolic trough is the only CSP application where and more environmentally friendly”, adds Barnett. energy storage technology is available for it”, he said. One of the biggest disadvantages of steam-based Smaller plants avoid systems like tower and dish technologies is that stor­ transmission problems age is not possible, according to Mehos. In order to increase the reliability of CSP, Inland Energy is devel­ Like hybrid plants, smaller CSP plants can provide a oping hybrid CSP-natural gas plants. reliable source of renewable energy without the prob­ “We were struck by the idea that, as valuable as lems that larger CSP projects face in connecting to renewable generating facilities are, many of them are the grid, remarks Shandalov. Smaller plants require not user-friendly”, says Barnett. “That is if the user is less land and there are fewer transmission con­ the grid and the utilities.” Inland is now developing straints because fewer MW can be more easily inte­ CPV system of Emcore Energy two projects with two gas turbines and one steam tur­ grated into the system. with (from left to right) Hong bine, which integrate into the natural gas plant eSolar has developed 46 MW power tower CSP Hou (CEO), Reuben Richards 50 MW of solar energy from trough technology. “So if plants. “Keeping plants under 50 MW avoids trans­ (Chairman of the Board), Chris you integrate the two, you have reliable gas energy mission constraints when connecting too many mega­ Larocca (Vice President and with solar. This provides real reliability and some en­ watts at once”, explains Shandalov. “It represents a General Manager of Solar vironmental benefit”, adds Barnett. Another benefit substantial opportunity to plug in to various parts of Power) and Ian Aeby (Director of of hybrid plants is that gas performs at a higher effi­ the grid without overloading it.” The US transmission Quality/Reliability). Photo: Emcore ciency when it is cooler, when the sun doesn’t pro­ infrastructure is not designed for renewable energy projects – which are often located in remote areas far from load centers, he adds. It’s easier to site smaller plants closer to population centers because they don’t require as much land. “Transmission, land use, environmental issues are all better when dealing with smaller plants”, says Shandalov. Smaller plants are just one innovation that solar developers are using to bring more energy to the grid. Despite all of the challenges related to fi­ nancing, transmission and reliability, NREL has a goal of seeing 1,000 MW of new installed CSP systems in the US Southwest by 2010, according to an NREL re­ port. In order to accomplish this target, utilities need to begin planning for major integration by identifying zones that are suitable for CSP. Planners need to identify transmission corridors that can move the power from these zones, claims Frier. Identifying where transmission is needed the most will speed up the permitting process, which can take four to five years, he adds. In the next decade, CSP is positioned to take a lead, says Mehos. “Our models show that there can realistically be greater than 100 GB solar capacity in the southwestern US alone.” A dedicated grid – one that ships electrons to other areas of the country – could result in even more capacity, he adds. Develop­ ers are installing CSP projects now and will be even more active in the next decade. “By the end of the year, there will be an additional 120 MW”, says ­Mehos. He also predicts that 8 to 10 GW of CSP could come online worldwide by 2020. As companies con­ tinue to develop CSP technologies, costs will come down. “This is the beginning of a period of having so­ lar as the mainstay for areas where solar is possible”, says Shandalov. Reid Smith, Lisa Cohn

78 Sun & Wind Energy 6/2009