Volume 3 solar thermal systems components and applications 3 18 – concentrating solar power

Volume 3 solar thermal systems components and applications 3 18 – concentrating solar power Volume 3 solar thermal systems components and applications 3 18 – concentrating solar power Volume 3 solar thermal systems components and applications 3 18 – concentrating solar power Volume 3 solar thermal systems components and applications 3 18 – concentrating solar power

3.18 Concentrating Solar Power B Hoffschmidt, S Alexopoulos, C Rau, J Sattler, A Anthrakidis, C Boura, B O’Connor, and P Hilger, Aachen University of Applied Sciences, Jülich, Germany © 2012 Elsevier Ltd All rights reserved 3.18.1 3.18.2 3.18.2.1 3.18.2.2 3.18.2.3 3.18.2.4 3.18.2.4.1 3.18.2.4.2 3.18.2.4.3 3.18.2.4.4 3.18.2.4.5 3.18.2.4.6 3.18.2.4.7 3.18.3 3.18.3.1 3.18.3.1.1 3.18.3.1.2 3.18.3.1.3 3.18.3.1.4 3.18.3.2 3.18.3.2.1 3.18.3.2.2 3.18.4 3.18.4.1 3.18.4.1.1 3.18.4.1.2 3.18.4.1.3 3.18.4.1.4 3.18.4.1.5 3.18.4.1.6 3.18.4.1.7 3.18.4.2 3.18.4.3 3.18.5 3.18.5.1 3.18.5.1.1 3.18.5.1.2 3.18.5.1.3 3.18.5.1.4 3.18.5.1.5 3.18.5.1.6 3.18.5.1.7 3.18.5.1.8 3.18.5.1.9 3.18.5.1.10 3.18.5.1.11 3.18.5.2 3.18.5.2.1 3.18.5.2.2 3.18.5.2.3 3.18.5.2.4 3.18.5.2.5 3.18.5.2.6 Introduction General Principles of Concentrating Systems Concentration Effect Energy and Mass Balance Grid-Connected or Island Systems Recooling Closed-circuit recooling systems Wet cooling systems Mechanical draft cooling systems Natural draft cooling towers Hybrid cooling towers Fan-assisted natural draft cooling towers Air-driven condensers Power Conversion Systems Solar Only Steam cycles Organic Rankine cycles Gas turbines Solar dishes Increase in Operational Hours Hybridization Storage Cogeneration Solar Cooling Principles and technologies of solar cooling Thermally driven cooling systems Absorption chillers Adsorption chillers Best-practice examples for solar cooling State of the art of solar cooling Market expectations for solar cooling Desalination Off-Heat Usage Examples Commercial SEGS Andasol 1–3 PS10, PS20 STJ Nevada Solar One Sierra SunTower Dish farm California PE AORA Kimberlina solar thermal power plant Others/under construction Research Solar One Solar Two CESA-1 DISS STJ SSPS Comprehensive Renewable Energy, Volume doi:10.1016/B978-0-08-087872-0.00319-X 596 596 596 597 597 597 597 597 598 598 599 600 600 600 600 600 603 604 605 605 605 609 611 611 612 612 612 613 613 614 614 614 615 615 615 615 616 617 619 620 620 622 622 622 623 623 624 624 625 626 626 627 627 595 596 Applications 3.18.5.2.7 3.18.5.3 3.18.5.3.1 3.18.5.3.2 3.18.6 3.18.7 3.18.7.1 3.18.7.2 3.18.7.3 3.18.8 3.18.8.1 3.18.8.2 3.18.8.3 3.18.8.4 References Others Studies GAST PHOEBUS Economical Aspects Environmental Aspects Emission Impact on Flora and Fauna Life Cycle Assessment Future Potential Desertec United States and Europe MENA Region Future Research Fields 627 629 629 629 629 630 630 630 630 631 631 631 634 634 634 3.18.1 Introduction Solar thermal energy is a booming field worldwide Many gigawatts of such energy are currently being built There are different competing technologies concerning the concentrator, heat transfer media, and power cycle Concentrating solar systems can be used for chemical reactions Concentrated solar chemical applications include fuel produc­ tion, for example, hydrogen, melting of metals which need high temperatures, and production of other chemical compounds The focus of this chapter is only the production of power and the use of the heat produced from concentrated solar thermal power systems 3.18.2 General Principles of Concentrating Systems 3.18.2.1 Concentration Effect Theoretically, concentrating solar systems can reach considerably higher temperatures without reducing their thermal efficiencies According to Carnot’s law, this means an improved conversion efficiency of the coupled thermodynamic cycle, so that the same amount of electricity can be produced by a smaller collector area The maximum thermal efficiency of a thermodynamic cycle is given by Carnot’s law: ηth; Carnot ¼ TP −TA TP where TP and TA are the process and ambient temperatures, respectively The upper boundary of the efficiency of solar thermal power plants is given by ηmax ¼ ηth ; Carnot ⋅ η absorber Figure shows the theoretical possible achievable efficiency as a function of the absorber temperature For simplicity, the absorber temperature is set equal to the process temperature In reality, the process temperature is less due to losses As can be seen from the 0.9 0.8 0.7 Dish η max 0.6 Solar tower 0.5 Parabolic trough 0.4 0.3 0.2 0.1 Flat-plate collector 400 600 800 1000 1200 1400 1600 1800 2000 (Tabsorber = Tprocess) (K) Figure Upper boundary of solar thermal power plant efficiencies Concentrating Solar Power 597 graph, the maximum efficiency increases when the process temperature is increased Each solar thermal technology has a maximum efficiency The highest efficiency is reached for the solar dish In order to withstand such high temperatures as well as high temperature gradients, suitable materials have to be chosen The solar tower reaches efficiencies above 60% and the operation temperatures match the operating temperatures of conventional power plants In comparison, the parabolic trough has less efficiency; however, it has already resulted in a standard commercial application Another very useful dimension that characterizes solar thermal systems is the concentration ratio C It is defined as the ratio of the collector aperture area to the receiver area The whole collector field has to be considered C¼ collector aperture area receiver area Flat-plate collectors have a concentration ratio of 1, parabolic trough and Fresnel collectors about 100, solar towers up to or more than 1000, and solar dishes around 4000 For example, for the Solar Tower Plant of Jülich (STJ; see Section 3.18.5.1.4) in Germany with a receiver area of more than 20 m2 and a heliostat field area of approximately 18 000 m2, a concentration ratio of around 900 has been reached 3.18.2.2 Energy and Mass Balance In order to thermally analyze a solar thermal concentrating system, the mass and energy conservation law has to be considered for the whole system as well as for each component Especially, the components of the solar cycle have to be considered in detail The thermal efficiency of solar thermal absorbers is given by the following equation: ηabsorber ¼ αeff − εσ s T CS where ε is the emission coefficient, αeff the effective absorptivity, σ the Stefan–Boltzmann constant, and S the solar input The concentrated solar energy received by an absorber is absorbed to a large degree, but losses also occur The losses at the receiver may be due to radiation, convection, and conduction, as well as thermal losses occur during the transport of heat transfer fluid (HTF) A detailed energetic consideration of each solar absorber technology can be viewed in Chapter 3.06 3.18.2.3 Grid-Connected or Island Systems Solar thermal concentrated power systems can be connected in grid as well as in island systems For small island systems, solar dish systems are a suitable solution Parabolic trough collectors (PTCs), Fresnel collectors, and solar towers may be grid or island systems Together with a thermal storage or after hybridization, dispatchable power can be provided 3.18.2.4 Recooling In a condensation power station, a main condenser or a turbine condenser, in which the steam flowing away from the turbine condenses out, can be used Condensation heat must be led away from the system, to the ambient This is done by the circulation of different coolants Using different systems, heat is delivered either to the hydrosphere (heat removal directly by the main condenser) or to the atmosphere (heat removal indirectly by air-cooled heat exchangers) 3.18.2.4.1 Closed-circuit recooling systems The closed-circuit recooling system is thermodynamically closed By means of a finned tube bundle heat exchanger, the medium on the product side is cooled (Figure 2) The use of finned tubes is necessary, because based on the low heat transfer coefficient of the air, a high air mass flow is necessary The large need for air can be avoided by enlarging the air-side heat exchange surface compared with the surface on the coolant side The big disadvantage of closed-circuit recoolers is the coolant temperature reached, which is close to ambient temperature This affects the energy efficiency of the power station 3.18.2.4.2 Wet cooling systems Thermodynamically, this system is described as an open process The warm coolant is injected into the cooling system and then conducted through a special fill material The loss of heat occurs by means of convection and mass transport (Figure 3) Cooling system System Air Figure Closed-circuit recooling system 598 Applications Cooling system System Air Figure Wet cooling system In such a system, lower temperatures occur and smaller transfer surfaces can be reached compared with a system using the closedcircuit coolers due to cooling to the wet-bulb temperature Disadvantages of wet coolers are vapor production and the demand for additional cooling water 3.18.2.4.3 Mechanical draft cooling systems As for air supply, there are two different cooling tower variations, supplying cooling air either by forced or by induced draft to the system Both variations are used in the closed-circuit as well as in the wet recooling system Figure shows different variations of arrangement • Forced draft A mechanical draft recooling system with a blower-type fan at the intake The fan forces air into the system A forced draft design typically requires more power than an equivalent induced draft design In combination with a wet recooling system, the fan on the intake of the cooling tower is more susceptible to complications due to freezing conditions • Induced draft A mechanical draft recooling system with a fan at the discharge, which pulls air through the tower The fan induces hot and wet air in combination with a wet cooling system 3.18.2.4.4 Natural draft cooling towers In the natural draft cooling tower, the necessary air mass flow is caused by density differences (buoyancy) Figure shows the function of a natural draft cooling tower with closed- and open-circuit cooling systems The heat exchange surfaces are right in the lower part of Hot water Hot water Fill Cold water Cold water Induced draft counterflow tower Induced draft counterflow tower with fill Hot water distribution Hot water Louvers Fill Centrifugal fan Fill Sump Cold water Forced draft counterflow tower with fill Figure Wet cooling tower arrangements Source: Geo4VA Fill Cold water Induced draft, double-flow cross-flow tower Concentrating Solar Power 599 Warm moist air Air out Coolant in Coolant in Heat exchanger Fill material Convection Convection and mass transfer Buoyancy Coolant out Air in Air in Air in Air in Collection basin Coolant out Figure Natural draft cooling towers: closed circuit (left) and open circuit (right) the tower, producing current by buoyancy Compared with the mechanical draft system, the advantage is that the natural draft cooling tower does not demand power for the fans The result is a positive impact on the achieved balance of the whole power station The natural draft wet cooling tower works in a similar way as the natural draft cooling tower with closed-circuit cooling system, but instead of the heat exchanger fill material is installed and the heat transfer mechanism functions in a different way 3.18.2.4.5 Hybrid cooling towers The hybrid cooling tower is a combination of a mechanical draft closed-circuit system and a wet recooling system The warm coolant is partly injected into the cooling system; the other part is cooled down by an air-driven heat exchanger and can afterward be injected into the cooling system (Figure 6) Diffuser Fan Mixers Heat exchanger Noise attenuator Drift eliminator Fill Rain zone Noise attenuator Water basin Figure Hybrid cooling tower Source: http://www.wetcooling.com 600 Applications The cooling tower can be operated according to the change in ambient temperature At a low-level ambient temperature, only the air driven by heat exchanger is in operation In case the ambient temperature increases, the wet cooling system can also be activated, to reach a very low coolant temperature Hence, problems that occur in winter in the wet cooling systems can be avoided and in summer very low coolant temperatures can be reached Moreover, the heat exchanger decreases fogging caused by the wet cooling system When applying the hybrid driving mode, coolant consumption is considerably reduced 3.18.2.4.6 Fan-assisted natural draft cooling towers The design is similar to the natural draft cooling towers (Figure 7) In addition, big fans are introduced in the lower cooling tower This additional air mass flow needs a smaller cooling tower However, the mass flow caused by buoyancy is still very high, so that the fans are driven with low speed 3.18.2.4.7 Air-driven condensers In the air-driven condenser, the steam flowing away from the turbine condenses directly by means of a surface heat exchanger and the heat is transported directly to the ambient (Figure 8) The heat exchanger tubes are finned to ensure better heat transfer Cooling air supply is realized by mechanical draft This system has the advantage that the steam is condensed directly so that no additional recooling system is required, and capital and operating costs decrease Furthermore, such systems work without control, because the condensation occurs by itself The disadvantage is that the accessible coolant temperature lies at ambient temperature level To fix this problem, the air-driven condenser can be combined with a hybrid cooling tower and a conventional surface condenser which transports the condensation heat to cooling water (Figure 9) This, however, requires higher capital costs Thus, lower pressure in the condenser can be reached even if the ambient temperature is high One such installed air-driven condenser, named LUKO of GEA Energietechnik GmbH, is shown in Figure 10 3.18.3 Power Conversion Systems 3.18.3.1 3.18.3.1.1 Solar Only Steam cycles At present, most solar thermal power plants convert solar power into electricity applying Clausius–Rankine cycles These steam cycles are basically of conventional technology and have only to be adjusted to the needs of the solar system For example, the steam generator works with an HTF like thermal oil for the evaporation of water When integrated with a solar cycle, some adjustments on the conventional cycle have to be made mainly in the heat recovery steam generator (HRSG), in order to consider the dynamical behavior of the solar part due to the changing weather conditions A steam cycle can be attached to almost all solar thermal systems except the solar dishes Figure 11 shows the operational scheme for a parabolic trough system with thermal oil as an HTF in combination with a conventional steam cycle Figure 12 shows the molten salt tower system with components of a conventional power plant, such as a steam generator Also a Fresnel system can be combined with the steam cycle of a conventional power plant Depending on the dimension of the power systems, one, two, or three pressure steam cycles in the steam are used Taking into consideration the HTF used, one-cycle and two-cycle systems are applicable in order to transport the heat effectively to the steam turbine The main advantages of the conventional steam cycle are as follows: Figure Fan-assisted cooling tower Source: GEA Energietechnik GmbH Concentrating Solar Power Windwall Counterflow module Parallel-flow module Forced draft fan Steam in Air removal system Condensate tank Figure Two-stage, single-pressure air-driven dispenser Source: GEA Energietechnik GmbH Figure Parallel Condensing system (PAC®) Source: GEA Energietechnik GmbH Figure 10 Installed air-driven condenser Source: GEA Energietechnik GmbH 601 602 Applications Figure 11 Process flow diagram of parabolic collector field combined with a steam power cycle 565 °C Hot salt storage tank Cold salt storage tank 290 °C Steam generator Conventional EPGS Figure 12 Process flow diagram of molten salt tower plant EPGS, electric power generating system Source: Sandia National Laboratories • • • • Reasonably high efficiency of the steam cycle, especially the steam turbine High scale of power capacity from MW to more than 1000 MW Applicable for the temperature ranges of solar thermal power plants Can be combined with hybrid systems as bottoming cycle to achieve higher efficiencies The disadvantages are as follows: • • • • High water consumption for the cycle and/or for recooling Personnel need to have knowledge of the complex systems Can hardly be used as remote automatic power plant Not applicable for small-scale power plants High efficiency is reached for large-dimension power plants due to the fact that for these plant sizes the components of the steam cycles are state of the art But with appropriate adjustments to the conventional parts, even for small power plants good thermal efficiencies can be reached, and the high investment of the collector field is compensated For the efficiency of a Clausius–Rankine cycle, recooling is important, because the backpressure of the steam turbine reduces the possible expansion of the steam from high pressure to low pressure (vacuum) The backpressure is dependent on the recooling temperature As solar power plants with recooling are located in regions with high ambient temperatures, this may have an impact when using recooling systems that use ambient air Concentrating Solar Power 3.18.3.1.2 603 Organic Rankine cycles Another alternative to conventional Clausius–Rankine cycles is the organic Rankine cycles (ORCs) used to convert thermal energy into electric energy They work in a similar way but use an organic fluid for the cycle These cycles are applied to lower temperature heat sources compared with water/steam cycles ORCs are mainly used in combination with geothermal power or waste heat recovery in industrial processes The range of the electrical power output is from some kilowatts to about 10 MW Additionally, thermal energy can be produced, which does increase the overall efficiency Due to the low temperatures, ORCs possess a lower theoretical Carnot efficiency at a maximum of 30% [1] than water/steam cycles The temperatures of the working fluids are limited to about 250–350 °C due to thermal stability thresholds [1] Working fluids include organic (hydrocarbon) fluids, namely, R-123, R-134a, R-245fa, R-717 (ammonia), R-601 (n-pentane), R-601a (isopentane), and C6H6 (benzene) Generally, an ORC consists of components that are also included in a Clausius–Rankine cycle The cycle consists of an evaporator, a superheater, a turbine/expander, a condenser behind the turbine, and a pump Because of the organic fluids and their different freezing points, usually lower than that of water, the condenser does not work in subatmospheric pressures and is water- or air-cooled In this configuration, ORCs with upper cycle temperatures of about 300 °C have an efficiency of about 12.5% [2] The efficiency of the basic Rankine cycle can be increased by recuperation and reheating, which lead to efficiencies of 20.5% for the same boundary conditions [2] In this case, the expanded fluid at the second turbine stage heats the fluid before entering the evaporator and is itself cooled down Reheating takes place after the expansion in the first turbine stage by redirecting the heat to the boiler Additionally, when higher thermal energy source temperatures are available, the combination of two or three ORCs using different working fluids with different saturation temperatures can increase the overall cycle efficiency Reasonably high cycle efficiencies compared with other energy conversion techniques can be obtained by an ORC Herein, the high turbine efficiency (up to 85% [1]) is the main advantage Due to the low turbine speed, low mechanical stress, and absence of moisture in the vapor nozzles (thus no erosion of the blades), a long lifetime is guaranteed Furthermore, the ORC has less operation and maintenance (O&M) costs and can be operated remotely because of the low pressures compared with steam cycles Simple start–stop procedures and good part load behavior make the ORC an attractive energy conversion system Despite these advantages, the negative aspects have to be mentioned The limited overall efficiency and the limited plant size due to the low source temperatures allow ORCs to be used only for certain applications Using organic fluids may not be an environmentally friendly option, and some of these are forbidden by the Montreal Protocol as they are capable of destroying the ozone layer Furthermore, dykes have to be installed to hinder fluid from entering the ground ORCs can work at lower temperatures, so the operating temperature of the parabolic trough can be reduced from about 400 to 300 °C This allows to use inexpensive HTFs (e.g., Caloria) and combine it with a two-tank thermal energy storage system Furthermore, lower operating temperatures result in lower capital cost for the solar components By using organic fluids for the power cycle instead of water in combination with air cooling of the power cycle, the use of water is reduced to only the amount for cleaning the mirror surfaces, which is about 1.5% of the total water use at the solar electric generating systems (SEGSs) [2] Another advantage, as mentioned before, is that the plant operation can be done remotely This further reduces the O&M costs of solar thermal plants The combination of ORC and solar collectors follows a trade-off (Figure 13) between the single efficiencies to gain the maximum overall system efficiency Increasing the temperature of the process will lead to a lower collector efficiency, but increases the ORC efficiency Choosing the right medium temperature has a great impact on the overall system efficiency ORC installations have increased in the last few decades because of the optimization of the efficiency of industrial processes and the intensive application of renewable energies like biomass and geothermal At present, the share of different applications in the ORC market is as follows: 48% biomass, 31% geothermal, 20% waste heat recovery, and 1% solar [3] The solar thermal share of the ORC market is still low, but some applications have been installed A choice of these installations is listed below: η Collector efficiency ORC efficiency Overall efficiency T Figure 13 Trade-off between collector and ORC efficiency Source: Quoilin S and Lemort V (2009) Technological and economical survey of organic Rankine cycle systems In: Proceedings of the 5th European Conference: Economics and Management of Energy in Industry Vilamoura, Algarve, Portugal, 14–17 April 604 Applications Figure 14 Solar ORC in Lesotho Source: Solar Turbine Group • Arizona Public Service (APS) built a MWe concentrated solar power (CSP) plant working with ORC in Arizona in 2006 Ormat International has supplied the 1.35 MWe gross power block and Solargenix Energy Inc was the system integrator and the vendor of the 10 340 m2 parabolic trough field [4] The ORC runs with n-pentane as the working fluid and the peak solar-to-electrical efficiency is about 12.1% at the design point The annual solar-to-electrical efficiency is 7.5% [5] • Another prototype plant was built by GMK in Germany in 2005 The ORC power output is 250 kWe, with the electrical efficiency of the system being about 15% A parabolic trough field has not been built; instead, the solar system has been simulated by a natural gas boiler [3] • The Solar Turbine Group developed small-scale systems for remote off-grid applications Figure 14 shows a kWe system installed at Lesotho Such systems have been developed to replace diesel generators in off-grid areas of developing countries By using materials available in this country and designing an ORC that runs at medium temperatures, the levelized electricity cost (LEC) can be lowered (~0.12 $ kWh−1 compared with ~0.30 $ kWh−1 for diesel) [3] 3.18.3.1.3 Gas turbines Introducing concentrated solar energy into a gas turbine (GT) system implements a new GT power plant concept The GT can be combined with a dish/Brayton system as well as a solar tower The receiver considered in both cases is a pressurized closed volumetric one The heat transfer medium is forced through the receiver structure and is heated by convection In the combination of the GT with a dish/Brayton system, the solar radiation is focused by the dish concentrator and it enters the receiver through a quartz window The window guarantees the closing of a pressure vessel Air as an HTF enters the combustor and passes through the receiver, where it is heated up If required, an additional burner enables the daily operation of the plant Hot air enters the turbine where it expands; the exiting hot air is connected to the GT combustor and the cycle is closed When the GT is combined with a solar tower (Figure 15), the receiver absorbs the concentrated solar irradiation and transfers the solar heat to pressurized air, which can be heated up to 1000 °C The hot pressurized air from the solar receiver is directly fed into the combustion chamber of a GT, where natural gas is added to further heat the air to the turbine firing temperature design point Solar unit Combined cycle plant Receiver Gas Heliostat field Gas turbine Figure 15 Scheme of solar hybrid GT system Source: DLR Steam cycle 622 Applications Plant construction was initiated in June 2008 Near the end of 2008, 24 360 heliostats were installed, with the tower and receiver installation completed by April 2009 The first full-power receiver operation began in June 2009 [38] The plant produces MWe of electricity, powering up to 4000 homes Design inlet steam conditions are 420 °C and 42 bar The solar power generating facility is interconnected to the Southern California Edison (SCE) grid, and the output of Sierra SunTower will reduce CO2 emissions by 7000 tons per year [39] 3.18.5.1.7 Dish farm California The development of dish/Stirling systems has been going on for about 40 years The combination of solar concentrated energy and the already almost 200-year-old technology of a Stirling motor has proved to be favorable Although these techniques were known for a long time, such systems have been built only in small noncommercial demo plants Only one midscale plant has been built by the LaJet Energy Company in Abilene, Texas This dish farm Solar Plant was constructed in 1984 consisting of 700 dishes, type LEC-460, in total The plant was built close to Warner Springs, northeast of San Diego, California Figure 44 shows a view of the dish farm at this location in the United States The electrical output is 4.92 MWe, produced by two different collector fields The first field produces water steam with a temperature of 276 °C, which is superheated to 371 °C by the second dish field The generated steam drives two steam turbines, of which the first has a nominal power of 3.68 MWe and the second is designed for 1.24 MWe For start-up, shutdown, and at low solar radiation, the second turbine is used, while, additionally, the first one produces electricity when there is enough solar-generated steam Other prototypes have been constructed, but they were all smaller compared with the electrical power output 3.18.5.1.8 PE NOVATEC BIOSOL has commissioned PE (Figure 45), a solar thermal power plant located in southern Spain It is based on linear Fresnel collector technology and has an electrical capacity of 1.4 MWe Since March 2009, it has been connected to the local grid and is selling electricity to the local network provider [40] PE consists of two rows of linear Fresnel collectors of about 807 m length each The net aperture area is about 18 490 m2 and the optical efficiency in the first year of operation is 67% The nominal power of the plant is 1.4 MWe and the projected power production is 2000 MWh a−1 An absorber tube is positioned in the focal line of the mirror field in which water is evaporated directly into saturated steam at 270 °C and at a pressure of 55 bar by the concentrated solar energy 3.18.5.1.9 AORA A concentrated solar tower plant is located in southern Israel This tulip-shaped power plant as shown in Figure 46 has an electrical power output of only 100 kW The corresponding technology was developed at the Weizmann Institute of Science (WIS) in Israel and was introduced to the market by the Israeli company AORA, with the aim of supplying CSP plants at the community level The developed technology enables to position an industry-standard micro-GT (Brayton thermodynamic cycle) on top of a 30 m tower Radiation is concentrated onto the tower by reflecting sunlight from an array of sun-tracking mirrors into a solar receiver, where it heats compressed air that drives the GT The microturbine of the solar unit provides both 100 kW of electric power and 170 kW of thermal power [41] Fuel combustion is used only when solar input is insufficient (e.g., cloud cover and sunrise/sunset) Figure 44 Dish farm Solar Plant Source: Sandia National Laboratories Concentrating Solar Power 623 Figure 45 The PE Fresnel power plant in Spain Source: NOVATEC BIOSOL Figure 46 AORA tower power plant in Israel Source: AORA The mirrors, with a total surface of 800 m2, can be mounted on less than 2000 m2 of land [42] Each mirror is located by a GPS and the computer system takes into account the different positions 3.18.5.1.10 Kimberlina solar thermal power plant Kimberlina is the first compact linear Fresnel reflector (CLFR) project in North America Located in Bakersfield, California, Ausra began construction of the power plant in March 2008, with the plant beginning operation in October 2008 [43] Situated in an area of 12 acres, the demonstration plant generates MWe The solar field aperture area is 26 000 m2 and the absorber length of each of the three lines is 385 m As an HTF, water/steam is used 3.18.5.1.11 Others/under construction 3.18.5.1.11(i) Gemasolar Gemasolar will become Spain’s first commercial molten salt central receiver power plant Construction of the plant began in 2008 in Fuentes de Andalucía, Seville, and could be completed in 2011 Figure 47 shows a picture of Gemasolar during erection of the power plant The installation covers 185 and will be able to generate 17 MW when it is up and running The energy generated (approxi­ mately 100 GWh yr−1) will power 25 000 homes in Andalusia Furthermore, the savings on carbon dioxide (CO2) emissions in comparison with other conventional plants are around 30 000 tons per year [44] The heliostat field consists of 2650 heliostats, each with 120 m2 reflective mirror area, totaling to 318 000 m2 of mirror area for the entire field The receiver, which will use molten salt as an HTF, will be installed on top of the tower whose height will be 150 m [45] Same as the other molten salt solar towers, Gemasolar also has a two-tank molten salt (sodium and potassium nitrate) storage system In the cold tank, molten salt is kept at a minimal temperature of 290 °C (to keep it from solidifying) From there, the molten 624 Applications Figure 47 Gemasolar tower plant (in September 2010) Source: Torresol Energy salt is pumped to the receiver and it exits at a temperature of 565 °C The hot molten salt is then pumped into a hot salt tank The steam is produced in a steam generator using the salt from the hot salt tank The salt leaving the steam generator is then pumped into the cold salt tank Gemasolar will have a 15 h storage capacity, which means that it can be operated day and night [45] The plant is designed to be in operation 6700 h a−1, which accounts for an availability of nearly 75% [46] 3.18.5.2 3.18.5.2.1 Research Solar One The experimental solar tower power plant Solar One (Figure 48) was built in Barstow, California, USA, and operated from 1982 until 1988, when it was replaced by Solar Two Solar One was designed to generate an electric power of 10 MWe, but exceeded this goal as it generated a net electric power of up to 11.7 MWe The height of the tower including the receiver was 90 m [47, 48] The receiver was a cylindrical-shaped single-pass superheat boiler, designed to generate steam at 510 °C and a pressure of 102 bar Corresponding to the receiver shape, a surround-type heliostat field was used The heliostat field consisted of 1818 heliostats, each having a reflective area of 39 m2, totaling to an area of 71 100 m2 for the entire field [48] During its 3-year power production phase, the Solar One pilot plant had annual availabilities above 80%, and during its last year, the availability was 96% [49] Figure 48 Solar One, near Barstow, California, USA Source: Sandia National Laboratories Concentrating Solar Power 3.18.5.2.2 625 Solar Two Solar Two was converted and adapted from Solar One and operated from 1996 to 1999 [50] The function of Solar Two (Figure 49) was to encourage the development of molten salt technology, which required several changes to be made to the Solar One construction The Solar One receiver, which was a cylindrical-shaped single-pass superheat boiler, could no longer be used and thus an entire new molten salt–heat transfer system had to be installed, as well as a new control system The heat transfer system included the receiver, piping, thermal storage, and a steam generator The surround-type heliostat field from Solar One was kept as it was and further 108 heliostats of a new type with an area of 95 m2 were added Due to the surrounding field, a cylindrical receiver shape was used Figure 50 shows Solar Two in operation The receiver was made up of 24 panels surrounding the internal piping, instrumentation, and salt holding vessels like a shell Each of the panels comprised 32 thin-walled, stainless-steel tubes that were connected on either end by flow distribution manifolds The receiver was able to withstand rapid temperature changes during cloud passages without damage The thermal storage medium consisted of 1500 tons of nitrate salt consisting of 60 wt.% NaNO3 and 40 wt.% KNO3 In molten salt power plants, there were two thermal storages There was a hot salt storage in which the salt had a temperature of 565 °C and a cold salt storage tank of 290 °C The temperature in the cold storage tank was kept at this level, as below that temperature the molten salt would solidify From the cold storage tank, the molten salt was pumped back into the receiver [51] Figure 49 Solar Two in the United States Source: US Department of Energy Figure 50 Solar Two in operation Source: Sandia National Laboratories 626 Applications 3.18.5.2.3 CESA-1 The CESA-1 solar tower was built on the Plataforma Solar de Almería (PSA), Spain, in 1983 and generated 1.2 MWe The tower height was 80 m and had the receiver fitted at 60 m With a thermal power of 4.95 MWth on the cavity receiver, the receiver’s HTF steam was brought to 520 °C and 100 bar The heliostat field consisted of 300 heliostats, each with a reflective mirror area of 39.6 m2, and thus the total reflective area was 11 880 m2 Figure 51 shows the heliostats and the tower of the CESA-1 plant The plant had a thermal storage, which uses molten salt as a storage medium The capacity of the thermal storage is 2.7 MWh in full-load operation [47] 3.18.5.2.4 DISS The project Direct Solar Steam (DISS) focuses on testing a 300 kW (thermal) parabolic trough test loop, using water as a heat transfer medium This test plant as seen in Figure 52 is located at the PSA in Almeria, Spain A single row of solar collectors, capable of producing 300 kW (thermal), was built with water as the HTF within a test loop to extract steam The row was divided into water evaporation and superheated steam sections In the first section, the water is evaporated by passing through nine solar collectors, whereas in the second section consisting of three collectors, superheated steam – that is, steam at a temperature of above 400 °C – is produced [52] The solar field is composed of a single north–south-oriented row of 11 PTCs connected in series, with a total length of 550 m and 3000 m2 of reflecting mirror [53] At the DISS test facility, the once-through, injection, and recirculation operation modes have been tested since the beginning of the 1990s Figure 51 View of the CESA-1 at the PSA in Spain Source: Sandia National Laboratories Figure 52 DISS test facility in Almeria, Spain Source: PSA Concentrating Solar Power 3.18.5.2.5 627 STJ The commercial operation of the STJ is accompanied by an intensive R&D program to facilitate the market introduction in larger plants The STJ power plant has been built to test the power plant as a whole and to investigate the systems’ operation Start-up and shutdown procedures, varying solar input, and storage operation are aspects that have to be investigated in the context of this process The solar thermal power plant’s operation is accompanied by computer simulations, which are validated by the power plant’s operational data Thus, the operation can be computed and new research aspects can be identified Furthermore, upscaling to larger plants can be done by using these results The following new innovations and upcoming improvements are currently under investigation in the STJ [54]: • • • • • new heliostat concepts and new means of control new absorber structures with high efficiencies storage concepts based on sand hybridization with fossil or fuels produced from biomass custom-made boilers for the integration of GTs 3.18.5.2.6 SSPS The SSPS (small solar power system) plant was the first central receiver plant in Europe and was built in 1981 on the PSA in Almeria, southern Spain, by the International Energy Agency (IEA) The plant had a design power rating of 500 kWe and used liquid sodium as a heat transfer medium The key feature of sodium as a molten salt working fluid is that it provides efficient, low-cost thermal energy storage The SSPS plant was reliable and proved to have good operational characteristics but suffered from safety and maintenance problems After a sodium fire in 1986, the plant was rebuilt without the sodium components The plant is still in use as a test facility The LEC of the SSPS, at approximately 0.48 € kWh−1, is considerably higher than the one corresponding to the larger SEGS parabolic trough plants and the Solar One tower plant which were built in California [55] This facility consisted of two parabolic trough solar fields with a total mirror aperture area of 7602 m2 The fields used the single-axis tracking Acurex collectors and the double-axis tracking PTCs developed by M.A.N of Munich, Germany [56] 3.18.5.2.7 Others 3.18.5.2.7(i) Themis The MWe Themis solar tower power plant is a research and development center located near the village of Targassonne, southern France The focus of the research center lies not only in solar towers but also in photovoltaic (PV) power [57] The plant was operated from 1983 to 1986 The 10 MWth receiver used molten salt as an HTF, generating steam with a temperature of 440 °C at 42 bar The heliostat field consisted of 200 heliostats which had an area of 54 m2 each, totaling to a reflective mirror area of 10 800 m2 [57] Figure 53 shows a bird’s-eye view of the Themis solar tower The tower had two experimental areas, where the project PEGASE (production of electricity from gas and solar energy) was realized [58] Figure 53 Bird’s-eye view of the Themis solar tower Source: CNIM Division Energy Solaire 628 Applications Figure 54 Solar tower at the Solar Research Facility in Rehovot, Israel Source: WIS 3.18.5.2.7(ii) Solar Research Facility Unit The Solar Research Facility of the WIS, shown in Figure 54, is located in Israel and its major feature is a solar power tower containing a heliostat field of 64 large, multifaceted mirrors of 56 m2 each Each heliostat tracks the movement of the sun independently and reflects its light onto a selected target on a 54 m high tower containing five separate experimental stations, each of which can house several experiments Light can be reflected toward any or all of these stations, allowing a number of experiments to be carried out simultaneously [59] The central receiver research facility has been in full operation since 1988 and provided power of up to MWth at equinox noon [60] 3.18.5.2.7(iii) EURELIOS In late 1980, the construction of the power plant EURELIOS was completed in Adrano, Sicily, Italy, and was operated until 1984 The nominal output was stated to be MWe at an insolation of kW m−2 at noon in equinox The receiver used was a cavity-type boiler that used water/steam directly as an HTF The steam reached a temperature of 512 °C at a pressure of 64 bar In an optimization process, the tower, which was constructed from steel, was raised from 50 to 55 m to the center of the receiver aperture Two types of heliostats were used The first type consisted of 70 CETHEL heliostats that had a reflective mirror area of 52 m2 The other type consisted of 112 MBB heliostats that had a reflective mirror area of 23 m2 [61] The thermal storage system had a capacity of 30 of reduced electrical output The storage system consisted of a salt tank and a water reservoir The salt storage system had a cold and a hot tank and used 1250 kg of a salt known as Hitec salt The water reservoir held 4300 kg of vapor [61] 3.18.5.2.7(iv) SEDC In June 2008, BrightSource Energy opened the Solar Energy Development Center (SEDC), a fully operational solar demonstration facility used to test equipment, materials, and procedures as well as construction and operating methods The SEDC is located in the Rotem Industrial Park in Israel’s Negev Desert, about 100 km southeast of Jerusalem The 4–6 MW test facility utility-grade superheated steam is piped from the boiler to a standard steam turbine 3.18.5.2.7(vi) CSIRO A close-packed heliostat field of more than 800 m2 reflector area was installed in 2006 at the CSIRO (Figure 55) solar tower at the National Solar Energy Centre (NSEC) in Newcastle, Australia The NSEC solar tower facility at the CSIRO comprises three main elements [62]: • A high-concentration tower solar array that uses 200 mirrors to generate more than 500 kW of energy It will be capable of achieving peak temperatures of over 1000 °C • A linear concentrator solar array that generates a hot fluid at temperatures around 250 °C to power a small turbine generator or adsorption chiller • A control room facility that houses the center’s communications and control systems and serves as an elevated viewing platform In late 2010, a second field was commissioned adjacent to the existing field This field consisted of 450 heliostats, with a thermal capacity of 1.2 MWth and will be used to demonstrate a 200 kW Brayton cycle GT [63] Concentrating Solar Power 629 Figure 55 CSIRO with the solar tower test facility Source: CSIRO 3.18.5.2.7(vii) Sunshine The solar tower, located in Nio Town, Japan, began operation in 1981 It has a nominal power of MWe The heliostat field consists of 807 heliostats, each with a mirror area of 16 m2 The open receiver has an aperture area of 15.4 m2 Steam is used as an HTF and a mixture of salt and water is used as a storage medium The water is heated up in the receiver of the tower from 38 to 512 °C [64] 3.18.5.2.7(viii) SPP-5 The solar tower SPP-5 is located in Krim, Ukraine It was constructed in 1986 and has a nominal power of MWe A total of 1600 heliostats with 25 m2 mirror surface each concentrate the solar radiation to the receiver The open receiver uses water/steam as an HTF and a storage medium [64] 3.18.5.3 3.18.5.3.1 Studies GAST A German–Spanish project named GAST coordinated by the companies Interatom and Asinel proposed in the late 1980s the construction of a 20 MW solar power plant in Spain using a tubular panel air-cooled receiver [65] For that reason, several components were tested at the PSA in Almeria As described in Reference 66, the high estimated investment costs and the low incident solar fluxes permitted by the tubes made it impractical to pursue the construction of the plant 3.18.5.3.2 PHOEBUS PHOEBUS was an open volumetric receiver study on a solar tower Air was considered as the HTF [67] It was one of the bases for further development that resulted in the erection of the first solar tower plant STJ (Jülich, Germany), which uses air in an open volumetric receiver in Jülich, Germany In the PHOEBUS study, an all-around heliostat field of 1000 heliostats with 150 m2 each was considered The receiver included hexagonal conic absorber modules Atmospheric air was considered as the HTF, and it was heated up by passing it through a metal wire mesh receiver to temperatures on the order of 700 °C and used to produce steam The designed power plant had a tower height of 130 m and consisted of two thermal cycles: an air and a water/steam loop Together with this study, a PHOEBUS consortium was formed with companies from Germany, Switzerland, Spain, and the United States, and at the end of the 1980s it made a prefeasibility study for the erection of a 30 MWe tower plant in Jordan [68] Unfortunately, the project could not obtain the necessary grants and financial support and did not come to eventual construction Technological development of key components followed through the German TSA Consortium Technology Program Solar Air Receiver, under the leadership of the company Steinmüller A 2.5 MWth air receiver facility comprising the complete PHOEBUS power plant cycle that included air recirculation loop, thermal storage, and steam generator was assembled on top of the CESA-1 tower in Spain at the end of 1991 [66] The plant was successfully operated by DLR and CIEMAT for nearly 400 h between April and December 1993, and for shorter periods in 1994 and 1999, demonstrating that a receiver outlet temperature of 700 °C could easily be achieved within 20 of plant start-up [69] 3.18.6 Economical Aspects Detailed cost data are not always available for most of the commercial solar thermal power plants This is the case, for example, for the first commercial SEGS plants This is partially because Luz did not actually track expenses against individual projects However, information on the financed sales price of the SEGS plants is available [70] For example, SEGS I cost 4400$ kWe−1 in 1984, and if normalized to 2003 dollars using the consumer price index, it corresponds to 7738 $ kWe−1 630 Applications Another possibility is to use estimations from studies Some years ago, a very important study, named ECOSTAR, made cost estimations for all available solar thermal technologies Among these technologies, the most mature technology today is the parabolic trough system that uses thermal oil as an HTF The ECOSTAR evaluation estimates LECs of 0.17–0.18 € kWh−1 for parabolic trough power plants of 50 MWe [9] Parabolic trough and solar tower technologies have similar LEC values that vary between 0.15 and 0.18 € kWh−1 The LECs for solar dish systems in the same large size are more than 10¢ higher If middle power plant size of 15 MWe is considered, the LEC is significantly higher, ranging from 0.19 to 0.28 € kWh−1 For a system of a solar tower integrated into a GT/combined cycle, LEC values below 0.09 € kWh−1 are achievable, but the technology neither is yet available nor is demonstrated in a realistic size In the conventional power market, the CSP competes with mid-load power in the range of 0.03–0.05 € kWh−1 Competitiveness is influenced not only by the cost of technology but also by a rise in the price of fossil energy and by the internalization of associated environmental costs such as CO2 emissions At present, the cost of power generated by solar thermal power plants including its transport via high-voltage direct current (HVDC) transmission lines amounts to 0.10–0.20 € kWh−1 – depending on the location, technology, and form of operation [71] However, these costs will drop significantly with economies of scale, refinements in the technologies, and increased research activities A further study made by the Sargent & Lundy Consulting Group for the US Department of Energy showed that trough and tower solar power plants can compete with technologies that provide bulk power and will reach values of LEC under 0.06 $ kWh−1 by the year 2020 for large power scales Especially for tower technology, the study implies that if commercial development is successful, then the LEC for deployment in 2020 will be less than for trough technology [72] The latest report of the European Renewable Energy Council (EREC) and Greenpeace demonstrates that depending on the level of irradiation and mode of operation, long-term future electricity generation costs of 0.06–0.10 € kWh−1 can be achieved [73] This presupposes rapid market introduction in the next few years 3.18.7 Environmental Aspects 3.18.7.1 Emission The most significant difference in the environmental impact of solar thermal power plants compared with fossil-fired power stations is that in solar-only operation, electricity is produced without emission of CO2, SO2, or NOx to the atmosphere Life cycle CO2 emissions of solar-only CSP plants are assessed at 17 g kWh−1 against, for example, 776 g kWh−1 for coal plants and 396 g kWh−1 for natural gas combined cycle plants [74] However, to the extent that some fossil fuel is used as a backup, a CSP plant or an ISCCS cannot be qualified as a ‘zero-emitting’ plant If the power plant is hybridized with a conventional fossil plant, emissions will be released from the nonsolar portion of the plant, but if biomass hybridization of a CSP is realized, then the direct emissions remain zero 3.18.7.2 Impact on Flora and Fauna In a solar tower, land use, although significant, is typically much less than that required for hydropower and is generally less than that required for fossil power (e.g., oil, coal, and natural gas), when the mining and exploration of land are included [75] No hazardous gaseous or liquid emissions that affect the environment are released during operation of a solar power tower plant For example, when melting salt is used as an HTF, if a salt spill occurs, the salt will freeze before significant contamination of the soil occurs Salt is picked up with a shovel and can be recycled if necessary Nevertheless, the use of molten salts and synthetic oil in a CSP plant bears some risk of spillage or fire This may in turn hinder acceptance of a project by the local population The use of air as an HTF, on the other hand, does not have environmental impacts at all In a CSP located in a desert, impacts will occur on water supplies and resources, if water is piped from limited aquatic systems, and these will directly affect desert flora and fauna, some of which may have declining populations In general, the impact of a CSP on flora and fauna is negligible, given that installations are not done in national reserved areas 3.18.7.3 Life Cycle Assessment It would appear sensible to align the restructuring of the energy supply not only with climate protection goals but rather to duly take other aspects of sustainable development into consideration It is important to consider water, material, and energy demand for the erection and operation of a CSP Concerning water demand, an 80 MW trough plant requires about 1.2 million cubic meters of water per year, mostly for cooling the steam cycle and for cleaning the mirrors Dry air cooling systems could considerably reduce water consumption To achieve this, the resource productivity of the various installations and the possibilities for their augmentation must be investigated on a mutual scale This also provides a background against which decisions about financial investment and funding can be made The sustainability of a solar power plant can be investigated using two methods First of all, the resource intensity can be examined using the material input per service unit (MIPS) method, and second, the cumulative fossil energy input of the power Concentrating Solar Power 631 plant can be examined Both methods can be used for the whole life cycle phases of the power plant, which means that the construction, operation, and dismantling of the plant are all taken into account for the calculations In order to assess the sustainability of the plant, it is necessary to compare the results with those of other energy converters MIPS calculations were compiled for solar thermal parabolic trough power plants and PV installations in the 1990s A comparison of the MIPS calculations of three types of power plants (parabolic trough, solar tower, and PV) was carried out by Fricke in 2008 [76] The comparison of the cumulative energy input returned considerably lower values for the solar tower power plant than for the PV installations The results showed that investment in the construction and development of solar thermal power plants has a large contribution to the restructuring of the energy supply structures with a view to enabling improved sustainability 3.18.8 Future Potential The sun-rich areas of the so-called Sun Belt of the Earth are ideal for the economically feasible employment of solar thermal power plants According to various studies, by 2010 at least 2000 MW of solar thermal power plants will be installed worldwide, and by 2020 there will be at least 20 000 MW According to a study by Greenpeace and EREC, predictions are for 138 000 MW to be installed by 2030 and 267 000 MW by 2040 The industries involved predict that with the constant development of up to 15–20 GW worldwide and with the simultaneous advancement of research and development, the full competitiveness against fossil fuels for mid-load electricity supply will be achieved in good locations by 2020 and that the same will be achieved for base-load electricity by 2030 Solar thermal power plants, with their inherent storage capability and hybridization solutions, will play a key role in providing sustainable electricity globally in the twenty-first century 3.18.8.1 Desertec In particular, the possibility of integrating low-cost energy storages or the additional firing of fossil or fuels produced from biomass in order to produce electricity on demand allows for the supply of a large portion of long-term requirements by solar thermal power plants Production locations for solar thermal power plant technologies are in the sunny regions of the earth, whereby the long-term target area for Europe is North Africa Along with the rapidly growing energy markets of the world’s Sun Belt, the technical requirements also exist in order to be able to use the electricity produced there in Central Europe when the appropriate network capacities for HVDC transmission have been built A detailed consideration of such solutions has been already done as can be seen in Reference 77 According to the ESTELA study, it is possible to build 20 GW of solar thermal power plants in North African states, since the technology is commercially available Moreover, such a plan will promote the industrial development of the North African region, because many components can be produced there Much of the electricity produced in North Africa can be transported to Europe Such technology is already used in many offshore projects in Europe and is expected to achieve a further improvement in terms of price and performance A further step was the Desertec concept (Figure 56), which schedules the use of renewable, mainly solar and wind, energy from the deserts A unique industry initiative to develop a reliable, sustainable, and climate-friendly energy supply from the deserts in the Middle East and North Africa (MENA) took place in 2009 In this initiative, 12 German, Spanish, and Algerian shareholders participate The Desertec concept describes the perspective of a sustainable supply of electricity for Europe (EU), the Middle East (ME), and North Africa (NA) up to the year 2050 The long-term objective is to cover a substantial part of the MENA electricity demand and 15% of the EU electricity demand by 2050 [71] A huge amount will be recovered from electricity generated from CSP plants The initial plans consider the construction of CSP plants in Morocco and the transport of electricity to Spain and Germany 3.18.8.2 United States and Europe One CSP project is proposed by Abengoa Solar Inc., the sole member of Mojave Solar LLC, for a nominal 250 MW solar electric generating facility to be located near Harper Dry Lake in an unincorporated area of San Bernardino County (Figure 57) The sun will provide 100% of the power supplied to the project through solar thermal collectors; no supplementary fossil-based energy source is proposed for electrical power production The plant is under construction and will start production in 2013 [45] Beacon Solar, LLC, a Delaware limited liability company, is proposing to construct, own, and operate the Beacon Solar Energy Project The project is a concentrated solar electric generating facility of parabolic trough technology proposed on an approximately 2012-acre site in Kern County, California This project will have a nominal electrical output of 250 MW, and commercial operation is planned to commence by 2014 [45] The proposed Victorville project would have a net electrical output of 563 MW Primary equipment for the generating facility would include two natural gas-fired combustion turbine generators (CTGs) rated at 154 MW each, two HRSGs, one steam turbine 632 Applications Concentrating solar power Hydro Photovoltaics Biomass Wind Geothermal CSP collector areas for electricity World 2005 EU-25 2005 MENA 2005 TRANS-CSP Mix EUMENA 2050 Figure 56 The Desertec concept Source: Desertec Foundation Figure 57 Plan for the Abengoa Mojave Solar Project Power Plant Source: CEC generator (STG) rated at 268 MW, and 250 acres of parabolic solar thermal collectors with associated heat transfer equipment The solar thermal collectors would contribute up to 50 MW of the STG’s 268 MW output Projects under review would generate more than 3000 MW Among them is the Ivanpah Solar Electric Generating System using solar tower technology The proposed project of BrightSource Energy and Solar Partners includes three concentrating solar tower power plants Each 100 MW site would require approximately 850 acres and would have three tower receivers and arrays (Figure 58); the 200 MW site would require approximately 1600 acres (or 2.5 square miles) and would have four tower receivers and arrays The Rice project could break ground as early as spring of 2011 creating 450 construction jobs during the 2-year construction period The project will employ 45 permanent operations staff and will have an annual operating budget of more than $5.0 million Concentrating Solar Power 633 Figure 58 Plan for the Ivanpah Solar Electric Generating System Source: CEC In the field of solar dishes also, several large projects with Stirling engine technology are now being developed Stirling Energy Systems Inc (SES) has announced plans for two large Stirling plants in California with a total capacity of 1600 MW Solar One has a capacity of up to 850 MW, which will be constructed in two phases of 500 and 350 MW consisting of 34 000 SunCatcher dishes SES has a PPA with SCE for this plant planned to be installed in the Mojave Desert The second plant, Solar Two, is designed to generate 750 MW, also included in a PPA with San Diego Gas & Electric (SDG&E) In the first phase 12 000 dishes (300 MW) will be built, and in the second phase 18 000 SunCatcher with 450 MW will be built These commercial-scale plants would be the first solar dish/ Stirling plants that are in a reasonable megawatt scale As described in Reference 78, a new 100 MW solar energy project will be located near the town of Tonopah in Nye County, Nevada When completed, Tonopah Solar Energy’s facility will supply approximately 480 000 MWh of clean, renewable electricity annually – enough to power up to 75 000 homes during peak electricity periods – utilizing its innovative energy storage capabilities The solar tower plant will be developed and owned by a SolarReserve’s subsidiary, Tonopah Solar Energy Another company, eSolar, is developing solar thermal tower power plants of 46 MW (and above) across the southwestern United States and globally The innovation of eSolar, as demonstrated through the Sierra SunTower facility, has led to a broad, global footprint of projects In New Mexico, eSolar has partnered with NRG Energy to develop a 92 MW solar power plant under a PPA with El Paso Electric Corporation This contract is the first and only contract to deliver solar thermal energy in New Mexico and will help El Paso Electric to meet its renewable portfolio goals eSolar has further projects under development with NRG in California Internationally, eSolar executed an exclusive licensing agreement with the ACME Group, a leader in the field of infrastructure in India, to develop up to 1000 MW of solar thermal power plants in India over the next 10 years ACME recently announced that commissioning will begin on the first eSolar power plant in the first quarter of 2010 In January 2010, eSolar announced a partnership with Penglai Electric, a privately owned Chinese electrical power equipment manufacturer, to build GW of solar thermal power plants in China by 2021 In Europe, mostly in Spain, 1000 MW of CSP are planned to be operational by around 2011 The greatest European market for CSP is located there An additional 10 000 GW are under planning and development, which could all go online by 2017 By 2013, with 2400 MW of CSP projects, Spain will topple the United States as the global leader for installed CSP capacity Most of these systems will include a storage system, and parabolic troughs make more than 90% of this capacity Spanish government interven­ tion with feed-in tariffs has driven this growth [79] SolarReserve, a US-based developer of utility-scale solar energy projects, and Preneal, a Madrid-based developer of renewable energy projects, announced in November 2009 that the autonomous government of Castilla-La Mancha has issued an environmental permit necessary for the construction of a 50 MW solar thermal power project This Alcázar Solar Thermal Power Project is being developed near the town of Alcázar de San Juan, about 180 km south of Madrid The project will generate more than 300 000 MWh of electricity per year or enough electricity to power almost 70 000 homes in the region [45, 80] The project started construction in 2011 and will bring significant local economic and employment benefits to the region A forecast for European countries by 2020, National Allowance Plans (NAPs), shows that more than 5000 MW will come from CSP in Spain, about 500 MW each for Portugal and France, and 600 MW for Italy and Greece together with Cyprus with more than 300 MW Even with a set of moderate assumptions for future market development, the world would have a combined solar power capacity of over 830 GW by 2050, with annual deployments of 41 GW This would represent 3.0–3.6% of global demand in 2030 and 8.5–11.8% in 2050 634 3.18.8.3 Applications MENA Region In MENA countries currently, there are four CSP power plants under construction, of which three are ISCC power plants These are in Kuraymat (Egypt), Ain Béni Mathar (Morocco), and Hassi R’mel (Algeria) The fourth project is the Shams One Solar Thermal Power Plant (Emirate of Abu Dhabi), a hybridization of parabolic trough technology with fossil-fired superheating [81] The ISCC Kuraymat is located about 87 km south of Cairo, Egypt, on the eastern side of the river Nile The ISCC Kuraymat power plant has been under construction since January 2008 and commercial operation is scheduled for the end of 2012 [45, 81] The concept includes 160 SKAL-ET PTCs arranged in 40 loops and a combined cycle power plant consisting of one GT, one HRSG, one steam turbine, solar heat exchangers, and all associated auxiliaries Under reference conditions, the solar cycle will generate about 50 MW of solar heat, which will enable the ISCC to generate 125.7 MWe of net electric power output The ISCC Ain Béni Mathar (integrated solar combined cycle power plant) is located in Ain Béni Mathar, about 90 km south of Oujda (Morocco) close to the Algerian border [82] In reference day mode operation, the solar parabolic trough cycle will generate about 58.7 MW of solar heat at a temperature of 393 °C; this enables the ISCC to generate 472.3 MWe of net electricity Without solar heat, the plant will generate 450.2 MWe of net electricity The ISCC Hassi R’mel power plant project is located about 60 km from Ghardaia in the northern central region of Algeria The ISCC Hassi R’mel uses parabolic trough and has a total gross electric power generation of 150 MWe, with a solar share of approximately 20 MWe The Shams One Solar Power Plant will be located in the Emirate of Abu Dhabi (UAE), about 100 km southwest of Abu Dhabi and 10 km from Madinat Zayed The Shams One Project started in June 2010 and the commercial operation is estimated for the third quarter of 2012 The concept includes 768 Abengoa solar parabolic collectors arranged in 192 loops, and fossil-fired backup HTF heaters [81] Under reference conditions, the plant will generate 100 MWe of net electricity 3.18.8.4 Future Research Fields For the successful deployment of concentrated solar thermal technology, basic research is needed, manufacturing industry providing hardware from mature production techniques as well as engineering services Basic research is provided both by research groups at universities and by research organizations Improving efficiency and reducing costs are top priorities for researchers trying to make CSP a reality The major challenge is increasing the operating temperature of the plants while maintaining efficiency In the future, researchers will try to strike the right balance between high efficiency, low pressure drop, high durability, and low cost Ongoing research projects aim also to discover more effective HTFs [83] They focus on the research of ideal HTFs, which provide a high thermal capacity, low viscosity, low melting point, and minimal corrosion of the system Another very important field of research activities will be the design and development of concepts for increasing the load hours of solar power plants Among them are the fields of hybridization and the search for appropriate storage materials In order to commercialize CSP as a dispatchable energy, industry has developed hybrid models that use natural gas or fossil fuel in combina­ tion with the solar resource But in view of long-term scarcity and related price volatility of fossil fuels, this approach provides only a medium-term solution Instead, industry players are now examining how CSP can be hybridized with biomass energy to achieve around-the-clock 100% renewable energy [84] A huge research potential is also the adjustment of the conventional part, for example, of a steam turbine, an HRSG, or a GT, in order to operate under conditions with dynamical thermal behavior and gradients which are common for solar thermal power stations References [1] Bini R and Manciana E (1996) Organic Rankine cycle turbogenerators for combined heat and power production from biomass Presented at the 3rd Munich Discussion Meeting ‘Energy Conversion from Biomass Fuels: Current Trends and Future Systems’ Munich, Germany, 22–23 October [2] Hassani V and Price HW (2001) Modular trough power plants In: Proceedings of Solar Forum 2001, Solar Energy: The Power to Choose Washington, DC, USA, 21–25 April [3] Quoilin S and Lemort V (2009) Technological and economical survey of organic Rankine cycle systems In: Proceedings of the 5th European Conference: Economics and Management of Energy in Industry Vilamoura, Algarve, Portugal, 14–17 April [4] Sinai J and Fisher U (2007) MW solar power plant using Ormat energy converter In: Proceedings of the 14th Sede Boqer Symposium on Solar Electricity Production 53 19–21 February [5] Canada S, Cohen G, Cable R, et al (2004) Parabolic trough organic Rankine cycle solar power plant Presented at the 2004 DOE Solar Energy Technologies, Program Review Meeting Denver, CO, USA, 25–28 October [6] Solugas Project Consortium (2010) www.solugas.com (accessed December 2011) [7] Buck R, Lüpfert E, and Telez F (2010) Receiver for solar hybrid gas turbine and CC systems (REFOS) In: Proceedings of the 10th International Symposium on Solar Thermal Sydney, NSW, Australia, 8–10 March [8] European Commission (2005) SOLGATE solar hybrid gas turbine electric power system Project partly funded by the European Community under the 5th RTD Framework Programme (1998–2002), Brussels [9] Pitz-Paal R, Dersch J, and Milow B (2005) European concentrated solar thermal road-mapping SES6-CT-2003-502578 Deutsches Zentrum fur Luft- und Raumfahrt, Roadmap Document, Brussels Concentrating Solar Power 635 [10] Alexopoulos S, Hoffschmidt B, Rau C, and Schwarzbözl P (2009) Simulation results for a hybridization concept of a small solar tower power plant In: SolarPACES Symposium Berlin, Germany, 15–18 September [11] Alexopoulos S, Hoffschmidt B, Göttsche J, et al (2008) First simulation results for the hybridization of small solar power tower plants In: Proceedings of the 1st International Conference on Solar Heating, Cooling and Buildings Lisboa, Portugal, 7–10 October [12] Alexopoulos S, Göttsche J, Hoffschmidt B, et al (2009) Solar tower power plant Jülich first experience with an open volumetric receiver plant and presentation of future enhancements In: Proceedings of the Conference on Renewable World Europe Cologne, Germany, 26–28 May [13] Zunft S, Hänel M, Krüger M, and Dreißigacker V (2009) High-temperature heat storage for air-cooled solar central receiver plants: A design study In: SolarPACES 2009 Berlin, Germany, 15–18 September [14] Laing D, Lehmann D, Fiß M, and Bahl C (2009) Test results of concrete thermal energy storage for parabolic trough power plants Journal of Solar Energy Engineering 131: 041007/1–6 [15] Price H and Hassani V (2002) Modular trough power plant cycle and systems analysis National Renewable Energy Laboratory Technical Report Operated by Midwest Research Institute, Battelle, Bechtel, Golden, CO, USA, January [16] Winter C-J, Sizmann RL, and Vant-Hull LL (1991) Solar Power Plants Berlin: Springer-Verlag [17] Khartchenko N (1995) Thermische Solaranlagen Berlin: Springer [18] Technology Program GAST (1988) Gas-cooled solar tower power station (in German) Technical Report Bergisch-Gladbach (D), Germany: Interatom GmbH [19] Steinmann W-D, Laing D, and Tamme R (2009) Development of PCM storage for process heat and power generation Journal of Solar Energy Engineering 131: 041009/1–3 [20] Bullough C, Gatzen C, Jakiel C, et al (2004) Advanced adiabatic compressed air energy storage for the integration of wind energy In: Proceedings of the European Wind Energy Conference, EWEC 2004 London, UK, 22–25 November [21] Gatzen C (2004) Modellgestutzte Wirtschaftlichkeitsanalyse innovativer Speichertechnologien am Beispiel eines adiabaten Druckluftspeichers In: Proceedings Symposium Energieinnovation ‘Erfolgreiche Energieinnovationsprozesse’ Graz, Austria, February [22] Crotogino F, Mohmeyer K-U, and Scharf R (2001) Huntorf CAES: More than 20 years of successful operation In: Proceedings of the SMRI Spring Meeting Orlando, FL, USA, 15–18 April; (2009) Journal of Solar Energy Engineering 131 [23] Siegel N, Kolb G, Kim J, et al (2007) Solid particle receiver flow characterization studies In: Proceedings of the 2007 ASME Energy Sustainability Conference Long Beach, CA, USA, 27–30 June [24] Weiss W and Biermayr P (2007) Potential of solar thermal in Europe Study within the Framework of the EU-Funded Project RESTMAC [25] Teng Y, Wang RZ, and Wu JY (1997) Study of the fundamentals of adsorption systems Applied Thermal Engineering 17(4): 327–338 [26] IEA Task http://www.iea-shc.org/task38/index.html (accessed April 2010) [27] AEE – Institut für Nachhaltige Technologie http://www.aee-intec.at (accessed April 2010) [28] Henning H-M, Häberle A, Lodi A, and Motta M (2006) Solar cooling and refrigeration with high temperature lifts – Thermodynamic background and technical solution In: Proceedings of the 61st National ATI Congress, ATI-IIR International Session ‘Solar Heating and Cooling’, pp 63–68 Perugia, Italy, 14 September [29] (2010) Solar heating and cooling for a sustainable energy future in Europe (FP6) European Solar Thermal Technology Platform (ESTTP) and European Solar Thermal Industry Federation (ESTIF) Belgium [30] Kalogirou S (2005) Seawater desalination using renewable energy sources Progress in Energy and Combustion Science 31(3): 242–281 [31] (2007) AQUA-CSP concentrating solar power for desalination Final Report by German Aerospace Center (DLR) Stuttgart, Germany, November [32] Kalogirou S (1997) Survey of solar desalination systems and system selection Energy 22(1): 69–81 [33] Spiegler KS and Laird ADK (1980) Principles of Desalination, Part B New York: Academic Press [34] Alexopoulos S and Hoffschmidt B (2009) Solar tower power plant in Germany and future perspectives of the development of the technology in Greece and Cyprus Renewable Energy 35(7): 1352–1356 [35] Solar Millennium AG (2010) The parabolic trough power plants Andasol to (information provided in the internet under www.solarmillennium.de) [36] (2006) 10 MW solar thermal power plant for southern Spain Final Technical Progress Report November [37] Broehl J (2006) A new chapter begins for concentrated solar power Journal Renewable Energy World, 11 February [38] eSolar (2010) Sierra SunTower Report on the First Six Months March (information provided in the internet under www.esolar.com) [39] eSolar (2009) Sierra SunTower A new blue print for solar energy Fact Sheet (information provided in the internet under www.esolar.com) [40] NOVATEC BIOSOL AG (2009) PE – World’s first Fresnel solar power plant in commercial operation Information Brochure (information provided by the company) [41] AORA (2010) Bringing solar thermal technology to every community under the sun Information Brochure (information provided in the internet under www.aora-solar.com) [42] Augsten E (2009) Make the desert bloom Sun & Wind Energy 9: 52–53 [43] Mehos MS (2009) Part 3: Task I – Solar thermal electric systems SolarPACES, Annual Report [44] Torresol Energy Press Dossier SENER 2010 (information provided in the internet under www.torresolenergy.com) [45] NREL Project Details 17 April 2009 (information provided in the internet under www.nrel.gov) [46] Martín JC (2007) SENER, NREL, CSP Technology Workshop Denver, CO, USA, March [47] Khartchenko NV (2004) Thermische Solaranlagen Berlin: Springer [48] Duffie JA and Beckman WA (2006) Solar Engineering of Thermal Processes Hoboken, NJ: John Wiley & Sons [49] Kolb GJ and Lopez CW (1988) Reliability of the Solar One plant during the power production phase Report SAND88-2664 Albuquerque, NM: Sandia National Laboratories [50] Sun Lab (2000) Solar Two demonstrates clean power for the future Report SAND2000-0613 Washington, DC: Sandia National Laboratories [51] Tyner C, Kolb G, Prairie M, et al (1996) Solar Power Tower Development: Recent Experiences Report SAND96-2662C Albuquerque, NM: Sandia National Laboratories [52] European Commission (2007) Concentrating solar power – From research to implementation Luxembourg: Office for Official Publications of the European Communities [53] Zarza E, Valenzuela L, León J, et al (2001) The DISS project: Direct steam generation in parabolic troughs – Operation and Maintenance Experience and Update on Project Status In: Proceedings of Solar Forum 2001, Solar Energy: The Power to Choose Washington, DC, USA, 21–25 April [54] Schmitz M (2009) Salt-free solar: CSP tower using air Renewable Energy World, January–February, pp 51–52 [55] Riffelmann K-J, Krüger D, and Pitz-Paal R (2002) Solar Thermal Plants – Power and Process Heat 6th International Summer School, Klagenfurt (Austria), July 21–August 4, 2000 [56] SolarPACES (2010) Solar parabolic trough http://www.solarpaces.org (accessed December 2011) [57] CNIM Division Energy Solaire (2010) Concentrating solar power plants http://www.cnim.com/en/cnim-and-solar-energy.aspx (last accessed November 2011) [58] Processes, Materials and Solar Energy Laboratory (PROMES) (2010) A laboratory of CNRS, France (National Centre for Scientific Research) http://www.sollab.eu/promes.html (last accessed October 2011) [59] Weizmann Institute of Science (WIS) http://www.weizmann.ac.il/weizsites/solarenergy/ (accessed 18 June 2007) [60] Becker M, Gupta B, Meinecke W, and Bohn M (1995) Solar Energy Concentrating Systems: Applications and Technologies Heidelberg, Germany: Muller Verlag [61] Strub AS, Gretz J, and Palz W; (Commission of the European Communities 1984) Eurelios, the MWe experimental solar thermal electric power plant of the European Community Final Report of the Construction of EURELIOS, assembled by the Industrial Consortium for the Implementation of the European Solar Power Plant [62] CSIRO (2006) New solar energy research facility in the limelight Reference: 06/52, Media Release, 31 March [63] Stein W, Kim J-S, Burton A, et al (2010) Design and construction of a 200 kWe tower Brayton cycle pilot plant In: Proceedings of the 16th Concentrating Solar Power SolarPACES Symposium Perpignan, France, 21–24 September [64] Mohr M and Svoboda P (1999) Praxis solarthermischer Kraftwerke Berlin, Springer 636 [65] [66] [67] [68] [69] [70] [71] [72] [73] [74] [75] [76] [77] [78] [79] [80] [81] [82] [83] [84] Applications Becker M, Gupta B, Meinecke W, and Bohn M (1995) Solar Energy Concentrating Systems Heidelberg, Germany: Muller Verlag Romero M, Buck R, and Pacheco JE (2002) An update on solar central receiver systems, projects and technologies Transactions of the ASME 124: 98–108 Keintzel G and Finker A (1995) PHOEBUS: Ein Solarturmkraftwerk vor der Markteinführung In: VDI Berichte, Solarthermsiche Kraftwerke II, pp 35–51, Nr 1200 Heinrich P and Schmitz-Goeb M (1995) 2,5 MW-Demonstrationsprogramm zum air receiver PHOEBUS In: VDI Berichte, Solarthermsiche Kraftwerke II, pp 23–34, Nr 1200 Haeger M (1994) Phoebus technology program: Solar air receiver TSA PSA Technical Report: PSA-TR02/94 July Luz International Limited (1990) SEGS IX Proposal for Project Debt January Desertec Foundation Red Paper (2009) An Overview of the Desertec Concept Berlin, Germany Sargent & Lundy Consulting Group (2003) Assessment of parabolic trough and power tower solar technology cost and performance forecasts Final Report NREL Report NREL/ SR-550-34440 US Department of Energy, October EREC (2008) Lead authors: Teske S, Schafer O, and Zervos A Energy [r]evolution: A sustainable global energy outlook Greenpeace Report Brussels, Ocober Renewable Energy Essentials (2009) Concentrating solar thermal power IEA, CSP Brochure Anderson D and Ahmed K (1995) The case for the solar energy investments World Bank Technical Paper Number 279 – Energy Series Washington, DC: World Bank Fricke B (2007) Vergleich der Zukunftsfähigkeit eines Solarturm-Kraftwerks mit der anderer Energiekonverter anhand des Material-Inputs-Pro-Serviceeinheit (MIPS) und des kumulierten Energieaufwands (KEA) Diplomarbeit, Jülich, Germany, Juli Zweibel K, Mason J, and Fthenakis V (2007) A solar grand plan – By 2050 solar power could end U.S dependence on foreign oil and slash greenhouse gas emissions Scientific American Magazine, 16 December SolarReserve signs power contract with NV Energy for utility scale solar power project in Nevada Press Release, 22 December Price T (2010) Spain’s CSP policy: Do we follow the leader? CSP Today, March SolarReserve (2009) SolarReserve and Preneal receive environmental permit for 50 MW solar energy project in Spain Press Release, 17 November (information provided in the internet under www.solarreserve.com) Brakmann G, Dolejsi M, Kretschmann J, and Klingler R (2010) CSP in the Middle East and North Africa (MENA) In: Proceedings of the 16th Concentrating Solar Power SolarPACES Symposium Perpignan, France, 21–24 September Brakmann G, Badaoui N-E, Dolejsi M, and Klingler R (2010) Construction of ISCC Ain Béni Mathar in Morocco In: Proceedings of the 16th Concentrating Solar Power SolarPACES Symposium Perpignan, France, 21–24 September Cohn L and Smit R (2008) The future: Widespread use of CSP? Sun & Wind Energy 2: 42–53 Chhabara R (2009) CSP–biomass hybridisation: A truly sustainable solution? CSP Today, 29 December ...596 Applications 3. 18. 5.2.7 3. 18. 5 .3 3 .18. 5 .3. 1 3. 18. 5 .3. 2 3. 18. 6 3. 18. 7 3. 18. 7.1 3. 18. 7.2 3. 18. 7 .3 3 .18. 8 3. 18. 8.1 3. 18. 8.2 3. 18. 8 .3 3 .18. 8.4 References Others Studies... Figure 10 3. 18 .3 Power Conversion Systems 3. 18 .3. 1 3. 18 .3. 1.1 Solar Only Steam cycles At present, most solar thermal power plants convert solar power into electricity applying Clausius–Rankine... Chapter 3. 06 3. 18. 2 .3 Grid-Connected or Island Systems Solar thermal concentrated power systems can be connected in grid as well as in island systems For small island systems, solar dish systems