Solar thermal power plant
A solar thermal power plant or solar thermal power plant (also solar thermal power plant ) is a power plant that uses the heat of the sun as the primary energy source, either by absorbing its radiation or by using warm air. Solar thermal power plants are particularly to be distinguished from photovoltaics , which convert the sun's radiation directly into electricity.
Solar power plants that direct radiation from the sun with reflectors ( mirrors bundle) on a small area will be in English and CSP systems (from concentrated solar power called). They achieve a shorter energetic amortization period and, depending on the design, higher levels of efficiency than photovoltaic systems , but have higher operating and maintenance costs and require a certain minimum size. They can only be used economically in sunny regions of the world with high levels of direct sunlight.
Solar thermal power plants initially had lower specific investment costs per installed kilowatt than photovoltaic systems; However, due to the sharp drop in the price of solar modules from 2011, photovoltaic systems now have lower electricity generation costs . Since it is easy to install inexpensive heat storage systems or burners for chemical fuels in solar thermal power plants , which make these power plants base load capable , their system costs are estimated to be lower in the long term than with photovoltaic systems, which could play an important role in later phases of the energy transition. The reverse route, the coupling of solar energy into a gas and steam combined cycle power plant , is also possible and was first implemented in 2011 in the Algerian power plant Hassi R'Mel .
Solar thermal power plants with radiation bundling (CSP, concentrated solar power)
These power plants use focusing reflector surfaces to concentrate the incident sunlight onto a small area. The component located there is called an "absorber", similar to a solar collector . The reflectors or the absorber track the sun. Solar farm power plants collect the heat in many absorbers distributed over the area, while in solar tower power plants and paraboloid power plants the radiation from the sun is bundled with "point concentrators" on a focal point (or a small area). This type of energy generation is shown in various studies, among others by the German Aerospace Center (DLR) and the Trans-Mediterranean Renewable Energy Cooperation (TREC), great potential for economic energy generation in desert regions of North Africa and the Middle East as well as in the arid south of Europe (Spain, Italy etc.). These concepts are related to low-loss electricity transport to Europe or Central Europe.
Systems that generate steam are suitable for supporting and thus saving fuel in conventional steam power plants . In pure solar power plants, heat accumulators compensate for fluctuating solar radiation; alternatively, other energy sources can support the generation of heat in times of low radiation. This happens, for example, in Austria , where solar thermal systems are already widespread. You combine solar collectors, bio-heating plants and conventional replacement or peak energy power plants. Since solar thermal energy supplies little energy in spring and autumn and almost no energy in winter, other power plants are also switched on during this time so that the installation can be used all year round. Alternatively, seasonal heat storage systems can also serve the same purpose, with simultaneous oversizing of the system in the summer months.
Solar farm power plants
The collector field of a solar farm power plant consists of many parabolic trough or Fresnel collectors connected in parallel , so-called line concentrators . The interconnection of paraboloid systems to form a large collector field is possible, but is very complex compared to line concentrators. Parabolic trough systems are already being operated commercially.
A heat transfer medium, either thermal oil or superheated steam, is heated in the collector field . With thermal oil systems, temperatures of up to 390 ° C can be achieved, which are used in a heat exchanger to generate steam . Direct steam generation (DISS = Direct Solar Steam) manages without such heat exchangers, as the superheated steam is generated directly in the absorber pipes. This means that temperatures of over 500 ° C are possible.
The steam is then fed to a centrally arranged steam turbine, as in a steam power plant, which is coupled to a generator. The turbines used today are specially adapted to the special conditions of use in solar thermal power plants. The highest possible degree of efficiency enables a smaller solar field with the same output of the power plant. This lowers the investment costs and makes the electricity generated more profitable. The day / night cycle and changing weather conditions also require very short start-up times for the steam turbine. For these reasons, two-casing steam turbines with reheating are usually used in solar thermal power plants. Before entering the downstream low-pressure turbine, the exhaust steam from the high-pressure turbine is fed at constant pressure into a reheater in the steam boiler, where it is superheated again. The steam circuit works in this way with a higher average temperature than a circuit that has not been reheated. This increases the efficiency, because the turbine produces a higher output with the same heat input in the boiler. The moisture content in the low-pressure turbine and the otherwise common corrosion caused by water droplets are also reduced. The reheating of the steam increases the efficiency and service life of the turbine. A special housing design protects the steam turbine from cooling down too much at night and, in addition to the low weight of the rotor, contributes to a short start-up time. In order for the steam turbine to work as effectively as possible, the steam must be condensed at a low temperature. The highest efficiency is achieved with the help of water cooling, such as. B. in the case of Andasol . In the event that - as in many desert regions - no cooling water is available in sufficient quantities, dry cooling systems can be used at the expense of efficiency.
The particular advantage of this type of power plant is the conventional, relatively easily available technology.
Due to rising energy costs, there is also growing interest in smaller systems that enable decentralized supply. By coupling electricity, process heat, cooling and storage technologies, such systems could also work economically.
Parabolic trough power plants
technology
Parabolic trough collectors consist of curved mirrors that focus the sunlight onto an absorber tube running in the focal line. The length of such collectors is between 20 and 150 meters, depending on the type of construction. The concentrated solar radiation is converted into heat in the absorber tubes and transferred to a circulating heat transfer medium. For cost reasons, the parabolic troughs usually only track the sun uniaxially. They are therefore arranged in a north-south direction and are only tracked or “tilted” according to the height of the sun during the day.
MIT scientists are currently working on a prototype that could significantly improve the efficiency of parabolic trough power plants. The hybrid system concept envisages generating not only thermal but also electrical energy in the absorber lines. In this design, the absorber lines consist of three nested concentric tubes with different functionality. The innermost tube is used to dissipate heat and is only partially filled with liquid, the rest of the volume is taken up by steam. The vapor condenses within the system on a connected condenser surface and the liquid resulting from the phase transition closes the liquid cycle. Theoretically, this system does not require any pumps and the heat energy gained can be fed to other process systems on the condenser surface by coupling. The middle tube serves as an absorber surface for the solar energy and is connected to the inner tube via a thermoelectric material in the form of "legs". The large temperature gradient between the tubes leads to a potential difference due to the Seebeck effect , which enables the use of electrical energy. A vacuum between the middle and outer tubes prevents the heat generated on the absorber surface from being released into the environment.
history
The history of solar thermal power plants goes back to the second half of the 19th century, when inventors such as William Adams , Augustin Mouchot , Alessandro Battaglia or John Ericsson built various systems for solar energy conversion such as solar cookers , solar-powered stills , chillers and boilers for solar-powered steam engines . Finally, in 1912, parabolic troughs were used to generate steam for a 45 kW steam motor pump in Maadi / Egypt by Frank Shuman and Charles Boys . The five rows of collectors had a length of 65 m, an aperture width of 4 m and a total aperture area of 1,200 m². The tracking took place automatically with the help of a thermostat. A certain amount of heat storage for night-time operation was also possible. The price was then 31,200 marks. The system provided “steam for 50 horses with ten hours of work per day”.
In 1916, the German Reichstag approved 200,000 Reichsmarks for a parabolic trough demonstration in German Southwest Africa . However, due to the First World War and the emerging petroleum age, there was no implementation.
Parabolic trough process heat demonstration systems were installed in the USA between 1977 and 1982 .
In 1981, a demonstration system with 500 kW electrical power was put into operation on the Plataforma Solar de Almería in Europe .
Commercial operation began in the USA in 1984. The nine SEGS power plants (SEGS = Solar Electricity Generation System) in Southern California produce a total of 354 MW . Another power plant called Nevada Solar One with an output of 64 MW was built in Boulder City / Nevada and went online in June 2007. The absorber tubes for this were supplied by the German Schott AG , which was already involved in the Californian power plants. The steam turbine, an SST-700 working with reheating with an electrical output of 64 MW, was supplied by Siemens AG . The efficiency of this type of power plant is given as 14%. Further power plants are being built in Morocco, Algeria, Mexico and Egypt, among others.
In Andalusia , Spain , from June 2006 to summer 2009, Andasol , three systems of 50 MW each, was currently the largest solar power plant in Europe. Andasol 1 went online in December 2008 and was officially inaugurated on July 1, 2009. Andasol 2 started test operations in mid-2009, Andasol 3 in 2011. The insolvent German company Solar Millennium was significantly involved in these solar power plants with project planning, technical development and control. As for almost all Spanish parabolic trough power plant projects, Siemens AG supplied the steam turbines and generators. This type of power plant, along with other types, has also been proposed for the Grand Solar Plan and the DESERTEC project , but a final decision on the technology has not yet been made.
In Abu Dhabi ( United Arab Emirates ), Shams-1 , the world's largest solar thermal power plant at the time, went into operation on March 17, 2013. It has an area of 2.5 km² and is supposed to supply 20,000 households with energy.
Fresnel collector systems
The so-called Fresnel mirror collectors are a further development of the parabolic troughs. Several parallel, non-curved mirror strips arranged at ground level (based on the principle of a Fresnel lens ) reflect the incident direct sunlight onto the absorber tube. The strips are tracked uniaxially. An additional secondary mirror behind the tube directs the radiation onto the focal line. This concept is currently in the practical testing phase.
This construction combines the functional principles of parabolic trough collectors and tower power plants, with both curved mirrors and multi-axis sun tracking systems being dispensed with and the modular structure being retained. Cost advantages are expected from the use of the more straightforwardly produced, non-curved mirror strips. In contrast to most parabolic trough designs, the absorber tube is not moved. In this way, very long collectors can be built that have low flow resistance for the heat transfer medium due to the lack of pipe bends and flexible connections. This contrasts with shading losses between the mirror strips.
Such a system has been supporting steam generation in an Australian coal-fired power station since 2004. The technology is being tested by the University of New South Wales and Sydney. After its complete completion, the plant for the Liddell power station in the Hunter Valley , about 250 km northwest of Sydney , will generate around 15 MW th and thus contribute to fuel savings. It is an approximately 60 m × 30 m field made up of level mirrors that concentrate the sunlight on approximately 10 m high lines above the collector field. There, steam at a temperature of around 285 ° C is generated using direct steam.
Since July 2008, on behalf of Gas Natural in Seville, Spain, a 352 m² system from PSE AG from Freiburg has been in operation with a peak output of 176 kW, which uses the generated process heat to drive an absorption chiller and thus cools a building at the University of Seville .
The Fresnel solar power plant PE 1 (Puerto Errado 1) of the Karlsruhe-based company Novatec Solar in Calasparra, Spain, has been in continuous commercial operation since March 2009 . The solar power plant has an electrical output of 1.4 MW and is based on linear Fresnel collector technology. In addition to a conventional power plant block, PE 1 includes a solar steam generator with a mirror surface of approx. 18,000 m².
To generate steam, directly irradiated sunlight is concentrated on a linear receiver at a height of 7.40 m with the help of 16 rows of flat mirrors. An absorber tube is installed in this focal line of the mirror field, in which the concentrated radiation evaporates water directly into saturated steam at 270 ° C and 55 bar. As a result of the development of a new receiver design, superheated steam with temperatures above 500 ° C has been generated at the Puerto Errado 1 Fresnel power plant since September 2011. A more detailed description of the PE-1 system with several pictures can be found in the web links.
Based on the positive experience with the PE-1 system, another Fresnel solar power plant with an output of 30 MW was built and put into operation on October 5, 2012. Puerto Errado 2 is the world's largest Fresnel power plant in operation with a surface area of 302,000 m² (0.302 km²).
Solar tower power plants
The solar tower power plant , also called central receiver power plant , is mostly a steam power plant with solar steam generation. The combustion chamber previously fired with oil, gas or coal is being replaced by a solar “combustion chamber” on a tower. When the sun is shining, hundreds to thousands of automatically positioning mirrors ( heliostats ) align themselves so that the sunlight is reflected on the central absorber ( receiver ). The strong concentration of solar radiation causes temperatures of up to several 1,000 ° C at the top of the tower. The technically sensible manageable temperatures are around 1,300 ° C. The temperature values and the consequent achievable thermodynamic efficiency are thus significantly higher than with solar farm power plants. The heat transfer medium used is either liquid nitrate salt , steam or hot air .
A similar light-bundling arrangement enables particularly high temperature values to be achieved in the solar furnace in order to drive physico-chemical processes, such as chemical reactions, sintering or melting of metals, melting glass, burning ceramics or investigating materials. The solar furnace at Odeillo Font-Romeu (see photo on the right) was built between 1968 and 1970 and is one of the largest in the world with 1 MW thermal output, approx. 3000 working hours per year and temperatures of up to 3,800 ° C.
Most of the time, however, the heat generated in the absorber is used to generate electricity via a steam turbine and gas expansion turbine . To do this, the heat transfer medium in the receiver is heated to up to 1000 ° C and then used to generate steam. This drives a turbine. In order for this to work efficiently, the steam has to be cooled after exiting the turbine, as in a solar farm power plant. If there is sufficient water available, water can be used for cooling. Since this is often not the case in desert areas, dry cooling systems are also used with a loss in efficiency. The electricity generated is fed into the public grid. In addition to the parabolic trough power plant, the solar tower power plant is now another well-developed type of system that can provide solar power economically, even if it is still connected to public funding programs.
The largest solar thermal system in the world is the Ivanpah solar thermal power plant with 392 MW. It went online on February 13, 2014 and, according to its own information, generates electricity for around 140,000 households.
On the PSA - a Spanish research facility near Almería / Spain - there are two test facilities CESA-1 (7 MW th ) and SSPS-CRS (1.2 MW th ). Various types of receivers, including German developments from DLR , are tested here.
In Germany, the construction of a solar thermal demonstration and test power plant in Jülich ( North Rhine-Westphalia ) began in July 2006, which began test operation in January 2009 and is expected to generate 1.5 MW el . Air serves as the heat transfer medium. Since the operating temperature of 600–800 ° C is very high, it is more efficient than other solar thermal power plants. Fluctuations in the range of services offered by solar radiation are to be compensated for in this system by means of a new type of heat storage made from ceramic fill. This means that electricity can be generated in the power plant relatively independently of solar radiation and therefore more consumption-oriented. The solar institute Jülich and DLR are in charge of the construction and further development of the system . In the future, this power plant could be operated conventionally with biomass in bridging phases in the absence of solar radiation . With the help of this tower technology, hydrogen can also be generated using solar energy. To do this, water vapor is passed through capillaries in the receiver, which are provided with a metal oxide-based redox coating. At temperatures above 800 ° C, water molecules are split, the oxygen oxidizes the metal and hydrogen is released (cf. Hydrosol project ). In a further step, methane can be obtained from this by consuming CO 2 (see Sabatier process ).
In Seville , a solar park with a total of 302 MW and different technologies is operated. At the end of March 2007, the first solar tower power plant built by the Spanish Abengoa group ( PS10 with 11 MW and an annual yield of 23 GWh ) was connected to the grid. The investment costs of around 35 million euros were subsidized with five million euros from the European Union from funds from the Fifth Research Framework Program . In the second expansion stage, a tower system with 20 MW (PS20) was built in 2009. After another plant with 20 MW (AZ20), five more parabolic trough power plants with 50 MW each are to be built.
The "high-tech solar power plant" Gemasolar has been operating in Fuentes de Andalucia near Seville / Spain since 2011 (start of operation in May, official opening in October) . The plant covers an area of 185 hectares. It has 2,650 mirrors, each with an area of 120 m², which focus the sun on an absorber that is built into a 140 m high tower. Salt at a temperature of over 500 ° C is used as a heat transfer medium; this also serves as a heat store so that electricity can be generated when the sky is overcast or even at night. With an output of 19.9 MW, Gemasolar can generate around 110 GWh per year - enough for 27,500 households. The operator is Torresol Energy, a joint subsidiary of the Spanish engineering company SENER and Masdar, the company responsible for the development of renewable energies in the Emirate of Abu Dhabi.
Paraboloid power plants
In parabolic power plants, also called Dish-Stirling or Dish-Farm systems, parabolic mirrors are mounted on a frame so that they can rotate in two axes. These reflect the sunlight onto a heat receiver placed in the focal point. This design is very compact - the mirrors are designed with diameters of three to 25 meters, which means that outputs of up to 50 kW per module can be achieved.
In the case of solar Stirling systems , a Stirling motor is connected downstream of the receiver , which converts the thermal energy directly into mechanical work. These systems achieve the highest levels of efficiency when converting sunlight into electrical energy. In an experiment in France with a parabolic mirror with a diameter of 8.5 m (area 56.7 m²) a net power of 9.2 kW was achieved, which corresponds to an efficiency of 16%. The modules are suitable for decentralized energy supply in remote regions and allow any number of these modules to be interconnected to form a large solar power plant.
In the rarely used dish farm systems, there is an absorber in the focal point, in which a heat transfer medium is heated and used to generate steam. For this purpose, several parabolic mirrors are interconnected, although they cannot currently compete economically with line concentrators and tower power plants.
Spread of the CSP power plants
Many systems are currently being planned or under construction. In the USA in particular, several plants with over 200 MW output and dry cooling are being built. The following list shows the solar thermal power plants with more than 10 MW output, which are already in operation or whose construction has started. With one exception, real production figures are unknown, there are only forecasts.
The Ivanpah solar thermal power plant, 60 km southwest of Las Vegas, is the world's largest CSP power plant (as of February 2014) . It has a nominal output of 392 MW.
In May 2014, Spain held the record of using this energy source with 2,303.9 MW and 50 solar thermal power plants. Most of the locations of these power plants are in the federal states of Andalusia and Extremadura. In 2012 alone, more than 2.4 million tons of CO 2 were saved in Spain compared to generation from fossil fuels .
In 2017 the state energy supplier of the oil state Dubai placed an order for a solar tower power plant with a nominal output of 700 MW. The power plant is to become part of the Mohammed bin Raschid al-Maktum solar park , which is to be expanded to an output of 5,000 MW by 2030. It is to be the largest solar tower power plant ever built, costing around $ 3.9 billion and generating electricity production costs of 6 ct / kWh.
| Surname | Location | technology | Power in MW |
Annual production in GWh (*) |
Heat carrier |
Storage / backup |
Start of production |
|---|---|---|---|---|---|---|---|
| Ivanpah Solar Power Facility |
 United States 35 ° 34 ′ 12 ″ N , 115 ° 28 ′ 12 ″ W.
|
tower | 392 | 940 | steam | without | since 2014 |
| Solar Electric Generating Station (SEGS) I-9 |
United States 34 ° 51'47 " N , 116 ° 49'37" W.
|
Parabolic trough | 353.8 | 654.6 | Thermal oil | gas | 1984-1990 |
| Solana Generating Station |
United States 32 ° 55 ′ 0 ″ N , 112 ° 58 ′ 0 ″ W
|
Parabolic trough | 280 | 603.57 | Thermal oil | Salt, 6 h | from 2013 |
| Genesis Solar Energy Project |
United States 33 ° 40 ′ 0 ″ N , 114 ° 59 ′ 0 ″ W
|
Parabolic trough | 280 | 576.11 | Thermal oil | without | since 2014 |
| Mojave Solar Project |
United States 35 ° 0 ′ 40 ″ N , 117 ° 19 ′ 30 ″ W
|
Parabolic trough | 280 | 617 | Thermal oil | without | from 2015 |
| Solaben 1-3, 6 |
 Spain 39 ° 13 ′ 29 ″ N , 5 ° 23 ′ 26 ″ W
|
Parabolic trough | 200 | 400 | Thermal oil | without | 2012-2013 |
| Andasol 1-3 |
Spain 37 ° 13 ′ 3 ″ N , 3 ° 3 ′ 41 ″ W
|
Parabolic trough | 150 | 330 | Thermal oil | Salt, 7.5 h | 2008-2011 |
| Noor 1–4 (Ouarzazate) |
 Morocco 31 ° 1 ′ 10.1 ″ N , 6 ° 51 ′ 53.4 ″ W
|
Parabolic trough | 160 (1) | Thermal oil | Salt, 3.0 h | 2016-2020 | |
| Solnova 1, 3, 4 |
Spain 37 ° 24 ′ 52.1 ″ N , 6 ° 16 ′ 1.6 ″ W.
|
Parabolic trough | 150 | 340 | Thermal oil | without | from 2012 |
| Crescent Dunes Solar Energy Project |
United States 38 ° 14 ′ 0 ″ N , 117 ° 22 ′ 0 ″ W
|
tower | 125 | 485 | salt | Salt, 10 h | from 2015 |
| KaXu Solar One |
 South Africa 28 ° 52 ′ 52 ″ S , 19 ° 35 ′ 35 ″ E
|
Parabolic trough | 100 | 300 | Thermal oil | Salt, 2.5 h | from 2015 |
| Shams solar power station |
 United Arab Emirates 23 ° 34 ′ 10 ″ N , 53 ° 42 ′ 50 ″ E
|
Parabolic trough | 100 | 210 | Thermal oil | without | from 2013 |
| Nevada Solar One |
United States 35 ° 48 ′ 0 ″ N , 114 ° 59 ′ 0 ″ W
|
Parabolic trough | 75 | 124 | Thermal oil | Steam, 0.5 h | 2007 |
| Alvarado 1 |
Spain 38 ° 49 ′ 40 ″ N , 6 ° 49 ′ 20.9 ″ W
|
Parabolic trough | 50 | 105 | Thermal oil | without | 2009 |
| Extresol 1, 2 |
Spain 38 ° 39 ′ 0 ″ N , 6 ° 44 ′ 24 ″ W.
|
Parabolic trough | 100 | 316 | Thermal oil | Salt, 7.5 h | 2009, 2011 |
| Ibersol |
Spain
|
Parabolic trough | 50 | 103 | Thermal oil | without | 2009 |
| Central Solar Termoelectrica La Florida |
Spain 38 ° 48 ′ 51.8 " N , 6 ° 50 ′ 16.2" W.
|
Parabolic trough | 49.9 | 175 | Thermal oil | Salt, 7.5 h | 2010 |
| Majadas 1 |
Spain 39 ° 58 ′ 1.2 ″ N , 5 ° 44 ′ 31.2 ″ W.
|
Parabolic trough | 49.9 | 104.5 | Thermal oil | k. A. | 2010 |
| Palma del Rio II |
Spain 37 ° 38 ′ 31.2 " N , 5 ° 15 ′ 25.2" W.
|
Parabolic trough | 50.0 | 114.5 | Thermal oil | k. A. | 2010 |
| La Dehesa |
Spain 38 ° 57 ′ 28.8 " N , 6 ° 27 ′ 50.4" W.
|
Parabolic trough | 49.9 | 175 | Thermal oil | Salt, 7.5 h | 2011 |
| Manchasol-1 |
Spain
|
Parabolic trough | 49.9 | 158 | Thermal oil | Salt, 7.5 h | 2011 |
| Martin Next Generation Solar Energy Center |
United States 27 ° 3 ′ 10.8 ″ N , 80 ° 33 ′ 0 ″ W.
|
Parabolic trough (steam only partially from the sun) | 470 | 89 (sun portion) | Thermal oil | k. A. | 2011 |
| Planta Solar 20 (PS20) |
Spain 37 ° 26 ′ 27.5 ″ N , 6 ° 15 ′ 36.2 ″ W.
|
tower | 20th | 48 | steam | gas | 2009 |
| Planta Solar 10 (PS10) |
Spain 37 ° 26 ′ 35 ″ N , 6 ° 15 ′ 0 ″ W
|
tower | 11 | 23.4 | steam | without | 2007 |
| Puerto Errado 2 |
Spain
|
Fresnel collector | 30th | 49 | steam | steam | 2012 |
| Gemasolar Thermosolar Plant |
Spain 37 ° 33 ′ 38 " N , 5 ° 19 ′ 54" W
|
tower | 19.9 | 110 | salt | Salt, 15 h | 2011 |
| Lebrija 1 |
Spain
|
Parabolic trough | 49.9 | 120 | Thermal oil | gas | 2012 |
- (*)Actual production figures are only available for SEGS, Solana Generating Station, Genesis Solar Energy Project and Nevada Solar One. The figures for all other plants are only forecast.
Effects on wildlife
In the previously existing solar tower power plants with bundling, it was observed that birds occasionally fall victim to the system. Birds that fly through the concentrated rays of the sun are burned instantly and suffer heat death in flight. So far there is no precise information about the number of birds killed in this way.
Solar thermal power plants without bundling
These power plants have no tracking reflectors, but use all of the incident radiation from the sun (global radiation, i.e. direct and diffuse radiation).
In solar pond power plants , layers of water with different levels of salt form the collector and absorber, while in thermal power plants this is the task of a large collector roof (similar to a greenhouse).
Thermal power plants
Thermal power plants, also known as updraft power plants, make use of the chimney effect , in which warm air rises due to its lower density. They consist of a large, flat glass roof (collector), under which the air on the ground warms up like in a greenhouse. The warm air rises and flows under the glass roof to a chimney in the middle of the system. The resulting updraft is converted into electricity with the help of one or more turbines , coupled with a generator. The low technical requirements for such a system are offset by the very low efficiency, even in the best case only about 1%, which makes the required effort and the size of such systems disproportionately large. To achieve an output that is comparable to that of a conventional coal or nuclear power plant, the chimney would have to be 1000 m or even higher and the collector would have to cover more than 100 km² (in this example the required diameter of the system would be more than 12 km) .
Solar pond power plants
In solar pond power plants , also called Salinity Gradient Solar Ponds / Lakes , shallow salt lakes form a combination of solar collectors and heat storage. The water at the bottom is much more salty and therefore denser than at the surface. If solar radiation is absorbed in the deeper layers, these heat up to 85 to 90 ° C. Due to the density gradient due to the different salt content, the heated water cannot rise, there is no convection and the heat is stored in the lower water layer. The stored heat can be used to generate electricity in a turbine-generator block and is available 24 hours a day if configured accordingly. Since the temperatures that can be achieved are comparatively low, working media that evaporate at low temperatures must be used to generate electricity. The conversion of heat into electricity is therefore carried out with the help of a so-called Organic Rankine Cycle power plant or with a Kalina process that uses ammonia vapor as the working medium.
Since the available temperature differences only reach about 60 K , the efficiency of such power plants is only low - in terms of thermodynamics, it is physically limited in this case to an ideal 15%, in practice significantly less is achieved. Nevertheless, solar pond power plants are particularly interesting for developing countries, since the sun-rich, vegetation-free and undeveloped areas that are available there can be used with relatively little investment. Sun pond power plants are also economically attractive if the thermal energy can be used directly without the detour via electricity generation, e.g. B. as process heat for drying or cooling.
See also
- Thermal solar system
- Solar thermal
- Solar oven (disambiguation)
- List of power plants
literature
- Chapter 5: Solar thermal power generation. In: Kaltschmitt , Streicher, Wiese (Hrsg.): Renewable energies: system technology, economic efficiency, environmental aspects. Springer-Vieweg, 5th edition from 2014 (corrected reprint), ISBN 978-3-642-03248-6 , pp. 263–348.
- Chapter 7: High temperature solar thermal systems. In: R. Stieglitz, V. Heinzel: Thermal solar energy: Fundamentals, technology, applications. Springer-Vieweg, Berlin / Heidelberg 2012, ISBN 978-3-642-29474-7 , pp. 487-594.
- M. Mohr, P. Svoboda, H. Unger: Practice of solar thermal power plants. Springer, Berlin / Heidelberg 1999, ISBN 978-3-642-63616-5 , 177 pp.
- Volker Quaschning : Renewable energies and climate protection. 4th edition. Hanser, Munich 2018, ISBN 978-3-446-45703-4 .
- Volker Quaschning: Renewable energy systems, technology - calculation - simulation. 9th edition, Hanser, Munich 2015, ISBN 978-3-446-44267-2 .
- Michael Sterner , Ingo Stadler (ed.): Energy storage. Need, technologies, integration. 2nd edition, Berlin / Heidelberg 2017, ISBN 978-3-662-48893-5 .
- Viktor Wesselak , Thomas Schabbach , Thomas Link, Joachim Fischer: Handbuch Regenerative Energietechnik. 3rd updated and expanded edition, Berlin / Heidelberg 2017, ISBN 978-3-662-53072-6 .
Web links
- How 18% of Europe's electricity needs could be met by solar thermal power plants in the Middle East and North Africa. In: dlr.de. Accessed on October 22, 2009 (DLR study).
- Description of the PE 1 Fresnel solar power plant with several pictures. (PDF; 712 kB) Accessed June 19, 2011 .
- Solar thermal power plants become practical project info from BINE Information Service
- Solar thermal power plants Topical information from BINE Information Service
- Solar thermal power plant RP-Energie-Lexikon
Individual evidence
- ↑ See English article Khi Solar One
- ↑ Michael Dale: A Comparative Analysis of Energy Costs of Photovoltaic, Solar Thermal, and Wind Electricity Generation Technologies. Applied Science 2013, doi: 10.3390 / app3020325 .
- ^ Pietzcker et al .: Using the sun to decarbonize the power sector: The economic potential of photovoltaics and concentrating solar power. In: Applied Energy 135, (2014), 704-720, doi : 10.1016 / j.apenergy.2014.08.011 .
- ↑ J. Antoñanzas et al .: Towards the hybridization of gas-fired power plants: A case study of Algeria. In: Renewable and Sustainable Energy Reviews 51, (2015), 116–124, doi : 10.1016 / j.rser.2015.06.019 .
- ↑ M. Mohr, P. Svoboda, H. Unger: Practice of solar thermal power plants. Springer, 1998, ISBN 3-540-65973-0 .
- ↑ Reducing Water Consumption of Concentrating Solar Power Electricity Generation. ( Memento of the original from February 15, 2010 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. (PDF; 894 kB) Report to Congress, US Department of Energy (Eng.)
- ↑ Platform for small and medium-sized solar thermal power plants
- ^ Nancy W. Stauffer: Harnessing solar energy . December 13, 2012.
- ↑ M. Simon: Parabolic trough solar collector with dual energy generation ( Memento from January 6, 2013 in the Internet Archive ). (German), December 17, 2012.
- ↑ Garcia et al., Performance model for parabolic through solar thermal power plants with thermal storage: Comparison to operating plant data . In: Solar Energy 85, (2011), 2443-2460, p. 2443, doi : 10.1016 / j.solener.2011.07.002 .
- ↑ Hans Herzberg: The solar power machine, an ideal power machine for the tropics. In: Kolonie und Heimat (1914), issue No. 35, p. 5.
- ↑ SCHOTT AG press release. October 3, 2005.
- ↑ Sunny prospects for solar thermal power plants. ( Memento of the original from April 27, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. In: Energy 2.0 May 2009, accessed December 8, 2009.
- ↑ Abu Dhabi: Huge solar thermal power plant goes into operation www.spiegel.de.
- ↑ Shams-1 project website www.shamspower.ae.
- ↑ PSE AG puts a new type of Fresnel solar collector system into operation. solarportal24.de, July 23, 2008, accessed on August 31, 2008 .
- ↑ Novatec Solar: The solar power plant Puerto Errado 1 , accessed on October 15, 2012
- ^ Swiss solar power plant with an area of 50 soccer fields , Tagesanzeiger, October 6, 2012
- ↑ Bright Source Energy via the LPT 550 solar tower ( Memento of the original from April 2, 2009 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. (engl.)
- ^ Ivanpah: World's Biggest Solar Power Tower Project Goes On-Line www.greentechmedia.com
- ↑ Ivanpah Project Facts ( Memento of the original from September 19, 2013 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. ivanpahsolar.com
- ↑ press release 174/06. Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, July 4, 2006, archived from the original on January 23, 2009 ; accessed on March 31, 2014 .
- ↑ DLR scientists succeed in solar hydrogen generation in a 100-kilowatt pilot plant
- ↑ Abengoasolar.com
- ↑ Solucar.es (Spanish and English)
- ↑ PROMES - Parabole Stirling. PROMES, May 15, 2006; archived from the original on May 17, 2007 ; Retrieved January 15, 2014 (French).
- ↑ NREL Concentrating Solar Projects (English), power plant clusters added, as of May 14, 2011
- ↑ World's largest solar power plant started operations spiegel.de February 15, 2014
- ↑ Overview of solar power plants in Spain 2014, pdf ( Memento of the original from May 18, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. www.protermosolar.com
- ↑ Technical data on solar power plants in Spain 2014 (in Spanish) www.protermosolar.com
- ↑ Dubai awards billions in the expansion of solar energy . In: Reuters , September 17, 2017. Retrieved September 17, 2017.
- ↑ Loan Programs Office: Ivanpah energy.gov April 2011
- ↑ Info a la poblac CST Extresol La Florida ( Memento of the original from September 24, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , P. 10, accessed on July 11, 2015
- ↑ Info a la poblac CST Extresol La Florida ( Memento of the original from September 24, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , P. 10, accessed on July 11, 2015
Map with all coordinates: