The solar tower harvests rays from mirror fields. Spain solar towers

djuga: this is without taking into account the cost of land. Solar power plants occupy a huge area due to the very low energy density of the sun. 1400W of energy comes to one square meter. Taking into account nights and days, this amount is halved, due to the rotation of the mirrors and the non-optimal position of the sun in the evening and in the morning, atmospheric losses still fall at least 2 times, but the efficiency is a maximum of 30%. In total, about 120 watts of electricity can be removed from the meter. For 120 MW, 120 million square meters or 120 square KILOMETERS would be needed. It is somehow doubtful that Israel agreed to occupy such an area with mirrors.

djuga January 14, 2018 | 15:56

geokrilov: It is somehow doubtful that Israel agreed to occupy such an area with mirrors.
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And what is the doubt when the tower is already standing? I believe that they took into account all their possibilities, weighed all the pros and cons.

djuga January 14, 2018 | 22:48

geokrilov: the real average power will not be 120 megawatts, but 3 times less.
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Do you think it's not worth it?
Sorry, but I do not know how you can do such calculations on your knee, without having all the data. But even if you are right, the first mobile phones weighed kilograms, and 100 years ago, the efficiency of a steam locomotive was about 7%, if my memory serves me right.

geocrilov January 15, 2018 | 04:23

djuga: I am a retired engineer (mechanic for spacecraft _MVTU), then there were no calculators and calculations were done on a ruler. I could explain about solar panels. Mobile phones are about communication and information. Ever since I considered something on BESM6 as a student, mobile phones have more cleaning power on board than the then mainframe. And the efficiency of a solar battery was then 12%, and now it does not exceed 20. Serial - 15 percent.
And yes, do not rely on alternative sources. Moreover, in Israel, it seems, they found gas fields and oil fields in the Mediterranean Sea. At worst, you can build a nuclear power plant.
The efficiency of a steam locomotive can be increased by a double-expansion machine and a heat exchanger at the outlet, but its theoretical efficiency is no higher than that obtained from a carnot cycle, and the efficiency of a solar solar station or a solar battery cannot be made higher than a certain value.
Alternative sources are justified where the power line cannot be dragged. For example, to power a weather station in Kolyma or cellular stations somewhere in the Krasnoyarsk Territory.

djuga January 15, 2018 | 07:49

geokrilov: Mobile phones are about communication and information.
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Yes, yes, and locomotives are about transport.
I have no doubts about your qualifications and experience. But we are not talking about a complete transition to alternative energy, but only about reducing the share that works on non-renewable resources. And from this point of view, the project being implemented is quite rational even with an efficiency of 20%. In addition, it is environmentally friendly and safe, does not require a huge infrastructure, unlike any thermal power plant.

Created on Thursday, 28 July 2011 12:13 Desert and the sun are inseparable concepts. Therefore, it is not surprising that deserts around the world are a magnet for any more or less serious companies specializing in solar energy - where else will a celestial body so invariably fulfill human whims responsibly? The desert in the state of Arizona (USA) also did not escape the close attention of "solar" specialists. It is here that the Australian company EnviroMission is preparing to realize its first, extremely ambitious project of creating a full-scale solar power plant (the so-called "solar tower").

"Full-scale" is putting it mildly. As planned by the developers, the power plant will be just the same huge! Upon completion, the 800-meter "solar tower" will become one of the most tall buildings worldwide. The total output, estimated at 200 megawatts, will allow it to supply 150,000 surrounding cities with renewable energy for at least 80 years.

EnviroMission CEO Roger Davey explained to reporters how the solar tower works, shared details about the preparations for the Arizona Project, and talked about the reasons why the project could not be implemented in the developer's native Australia.

How it works

The idea behind the EnviroMission Solar Tower is very simple. The sun illuminates and heats the ground at the foot of the tower, covered with heat-insulating material and representing something like a very large greenhouse. The heated air tends upward, flowing down to a single (central) hole in the cover. It is here, at the base of the tower, that the turbines are located, which produce electricity due to the natural upward flow of air.

It is difficult to take such a system seriously until you calculate necessary difference temperatures and you can’t increase the scale of the entire structure many times over - which is what the developers did. If you place the tower in a hot desert area, where the surface temperature during the day reaches 40 degrees Celsius, and add the influence of an artificially created "greenhouse effect", then the temperature in the air tank will already be 80-90 degrees Celsius. It remains to increase the greenhouse-reservoir around the tower so that its radius reaches several hundred meters, and you will get a solid volume of hot air.

It would also be useful to increase the height of the tower to several hundred meters (every hundred meters away from the earth's surface means a decrease in air temperature by one degree). The greater the temperature difference, the more the tower “draws in” hot air from the bottom, and the more energy the turbines produce.

The advantages of such an energy source are obvious:

• Since the power plant functions by temperature difference, and not by absolute temperature, it will continue to work in any weather;
• Since the soil gets very hot during the day, there is enough residual heat to continue working at night;
• Since an area of ​​dry hot soil is best suited for the indicated purpose, it is possible to build a “solar tower” on a more or less useless space in the middle of the desert;
• The power plant requires little or no maintenance - except for the occasional inspection and/or repair of the turbines - the tower "just works" from the start of construction until the structures that make up it exist;
• The "solar tower" does not require raw materials - no coal, no uranium, nothing but air and sunlight;
• It is completely waste-free and emits no pollutants other than warm air; certain areas of the greenhouse can even be used for their intended purpose for growing plants.

Project Arizona in numbers

What the developers from EnviroMission are planning is by no means the first attempt to create a “solar tower”. The experimental model, built in Spain, functioned for seven years (from 1982 to 1989) and proved the efficiency of the technology.

However, this time it will be much bigger. As already mentioned, the design height of the tower is 800 meters (only 30 meters below Dubai's Burj Khalifa, the high building in the world in 2010), the diameter at the top is 130 meters.

On the this moment developers from EnviroMission are busy buying land plot and preparation of project documentation. The cost of construction, according to them, will be 750 million US dollars. The energy efficiency of the power plant is expected to be 60%, which makes it much more efficient and reliable than other renewable energy sources.

It is known in advance where the energy produced by the "solar tower" will go - recently the State Energy Administration of Southern California signed a cooperation agreement (pre-purchase of electricity) with EnviroMission for a period of 30 years. Based on the results of financial modeling, the construction of the tower will pay off in just 11 years, despite the fact that its design is designed for more than 80 years of service.

Under the terms of the contract, electricity in american houses the Arizona solar tower will start shipping in early 2015.

Fantastic picture, isn't it? In front of you is a solar power plant of the so-called tower type with a central receiver. These power plants use a rotating field of heliostat reflectors to convert sunlight into electricity. They focus sunlight onto a central receiver built on top of a tower that absorbs thermal energy and drives the turbine generator. Each mirror is controlled by a central computer that orients its rotation and tilt so that reflected sunlight is always directed at the receiver. The liquid circulating in the receiver transfers heat to the heat accumulator in the form of steam. The steam drives the turbine of a generator that generates electricity, or is directly used in industrial processes. Temperatures on the receiver reach from 538 to 1482 C.

The first tower plant, called "Solar One" near Barstow, Southern California, was built back in 1980 and successfully demonstrated the application of this technology to power generation. This station uses a 10 MW water-steam system.

The largest solar power plant in the form of a tower was launched by Abengoa Solar. Its power is 20 MW. The PS20 solar tower is located near Seville, Spain, and was built next to the earlier smaller PS10 tower.

The PS20 solar power plant concentrates the beams reflected from 1255 heliostats on a tower 161 meters high. Each 120 m 2 heliostat mirror directs the sun's rays to a solar collector located at the top of a 165-meter tower. The collector turns water into steam, which drives a turbine. The station was built in 2007. By 2013, Spain plans to receive about 300 MW of electricity from solar installations of various designs, including towers.

The disadvantage of any solar station is the drop in its output power in the event of the appearance of clouds in the sky, and the complete cessation of work at night. To solve this problem, it is proposed to use not water as a heat carrier, but salts with a higher heat capacity. Salt melted by the sun is concentrated in a storage built like a large thermos and can be used to turn water into steam long after the sun has gone below the horizon.

In the 1990s, Solar One was upgraded to run on molten salts and a thermal storage system. Thanks to heat storage, tower power plants have become a unique solar technology that allows electricity dispatching at a load factor of up to 65%. With this design, molten salt is pumped from the "cold" tank at 288 C and passes through the receiver, where it is heated to 565 C, and then returned to the "hot" tank. Now hot salt can be used to generate electricity as needed. AT modern models such installations heat is stored for 3 - 13 hours.

Hot salt storage is shown in pink, cold salt storage is shown in blue. Red - marked with a steam generator connected to a turbine and a steam condenser (illustration taken from solarspaces.org).

The construction of such a station costs about 5 million euros.

Curiously, a solar tower can be used for more than just directly converting heat into electricity using turbines. The Israeli Weizmann Institute of Science in 2005 worked technological process obtaining zinc from zinc oxide in a solar tower. (Zinc oxide is formed during the working out of the life of most batteries - see article). Zinc oxide in the presence of charcoal is heated in a tower sunbeams up to a temperature of 1200 °C. The process produces pure zinc. Zinc can then be used to make batteries. Another option for its use is to place zinc in water and as a result chemical reaction get hydrogen and zinc oxide. Zinc oxide is sent back to the solar tower, and hydrogen can be used to run hydrogen engines as a clean fuel. This technology has been tested in the solar tower of the Canadian Institute for the Energies and Applied Research.

The Swiss company Clean Hydrogen Producers (CHP) has developed a technology for the direct production of hydrogen from water using parabolic solar concentrators. It turns out that water begins to separate into hydrogen and oxygen at a temperature of more than 1700 ° C, which is easily achieved in solar plants.

Thus, humanity is gradually mastering the largest source of energy at hand - the Sun.

A bewitching and mysterious structure rises from recently above the fields in the Sanlucar la Mayor area, near the center of Seville. A modern water tower, a scientific facility, a granary? But where are the numerous bright light arrows coming from, as if cutting through the air? They are visible for miles.

PS10 - Europe's first commercial thermal solar power plant of a rather rare type - "solar tower" (solar power tower) officially went into operation on March 30 this year. The power of the station built in Andalusia is 11 megawatts.

The principle of its operation is simple: a field of many heliostats - mirrors that track the movement of the Sun, collects light and directs it to the top. high tower where a bright sunbeam turns water into steam. The steam travels through pipes and eventually turns turbines connected to electrical generators.

PS10. The light from hundreds of large mirrors is so bright that it makes the dust and moisture in the air glow, which is why the rays are visible attacking the beautiful white tower. By the way, those mirrors that are visible in the foreground do not work for the tower. These are simply photovoltaic panels with concentrators standing side by side. Mirrors directed at the solar tower are not visible from this angle (photo by Solúcar).

Such a scheme has been created more than once in many countries, but the power plant operated by Solúcar Energía, a subsidiary of the industrial giant Abengoa, is perhaps the most impressive of all.

Its 624 mirrors, each measuring 120 square meters, cast light onto a beautiful concrete tower 115 meters high. This tower can be called a work of art - a huge figured cutout in it gives the building a visual lightness.

Solar tower under construction. Towering above the countryside, the structure looks impressive from afar. Up close too (photos by Solúcar).

No less impressive is the light around.

“When I got out of the car, I could barely open my eyes - the scene was too bright. Gradually, armed with dark glasses, I made out rows of mirrors and the center into which their rays converged - a set of pipes at the top of the tower ”- this is how David Shukman, a BBC correspondent who recently visited this station and even daring to climb up the tower during its operation.

At first he rode the elevator. But the last four floors had to be walked. The steps leading to the roof seemed to David to be scalding. In general, he compared upper floors towers with a sauna, despite the presence of powerful thermal insulation of the steam generator.

And such heating of the top of the tower is not in vain. The new Spanish power plant can generate up to 24.3 gigawatt-hours per year.

David Shukman on the roof of possibly the world's tallest "sauna" (BBC photos).

With the new station, Spain has taken the lead in this technology for utilizing sunlight, but the idea of ​​such towers is far from new.

Of the large structures of this type, one can recall the project Solar One - Solar Two. This demonstration solar power plant operated and developed from 1981 to 1999 in the Mojave Desert (California). AT latest version(Solar Two) the solar tower of this station was surrounded by 1926 heliostats, with a total area of ​​almost 83 thousand square meters. Its power exceeded 10 megawatts.

It is interesting that the sunlight did not heat the water, but the intermediate coolant - molten salt. It was a mixture of sodium nitrate and potassium nitrate. Water was already boiling from it, giving steam for the turbines (in the first version of the station - Solar One - the coolant was oil).

This technique allowed Solar Two to accumulate heat in reserve. On cloudy days or in the evening, the turbines ran on energy stored in large tanks of hot salt.

Solar Power Plant Solar Two (photos from sites en.wikipedia.org and parsnip.evansville.edu).

That tower and the field of mirrors have not gone away even now. It wasn't until 1999 that scientists converted Solar Two into a giant Cherenkov radiation detector to study the effects of cosmic rays on the atmosphere.

The experience of the Americans, however, has not disappeared: with their help and under a similar project in Spain, a 15-megawatt Solar Tres station is to be built.

The project involves the construction of a high solar tower surrounded by 2493 mirrors of 96 square meters each (see also this project page). total area mirrors will be 240 thousand square meters.

A capacious storage of molten salt (heated to a temperature of 565 degrees Celsius) will be able to operate steam generators for 16 hours after sunset. So in the summer, the station's generators will not stop day or night.

Externally, Solar Tres will be similar to Solar Two. In the meantime, you can only look at the scheme of the station. Hot salt storage is shown in pink, cold salt storage in blue. Red - steam generator connected to a turbine and condenser (illustration from solarspaces.org).

The European Commission allocated 5 million euros for this miracle. Creates a station international organization SolarPACES, which was also involved in the creation of the PS10. At the same time, companies from Spain, France, the Czech Republic and the USA are involved in the design and construction of Solar Tres.

Interestingly, the PS10 also provides energy storage. Only directly in the form of hot water vapor stored in a set of large tanks. Its reserve is enough for one hour of operation of the turbines without the Sun, so this system does not block the night break, but still gives the station some flexibility in case of temporary clouds.

It should be noted that PS10 is not the only solar power plant in Spain. There are several other large solar facilities operating here. various types. But the PS10 project is of particular interest: in the same place, engineers plan to build another twin installation called PS20. Only it will already generate a power of 20 megawatts, collecting light from more mirrors.

Engineers have developed a greenhouse that heats the air under the sun. A pipe is “drawn” above the greenhouse, in which this air would create traction. Turbines must be placed in the pipe. Everything seems simple, if you do not take into account that the diameter of the greenhouse should be a couple of kilometers, and the height of the pipe - 800 meters.

The Australian company EnviroMission, which surprised the world with the idea of ​​the “Solar Tower of Babel” back in 2002, seems to have finally found understanding, even if not in its homeland, where the project that had been started did not take place, but at least overseas.

Power plant with the banal name "solar tower" (Solar Tower), the Australians were going to build in Arizona. Faithful+Gould, a consulting company, was involved in the project in June this year to manage the construction. EnviroMission is now busy acquiring land and planning the first works on the site.

At the heart of the Solar Tower lies a huge round greenhouse. During the day in a desert area, the air and under normal conditions warms up to 40 degrees, and even under a transparent film or glass of a gigantic greenhouse, the temperature can reach up to 80 ° C.

As conceived by the Australians, the heated air will flow to the center of the structure, where an 800-meter pipe rises. At its base will be placed 32 turbines rotating generators. Their total peak power will be 200 megawatts.

The energy generated by the Solar Tower will be enough to power about 100,000 typical American households or a town with a population of more than a hundred thousand people. At the same time, compared to a conventional thermal power plant of equal capacity, a greenhouse with the highest pipe in the world will save about 900,000 tons of carbon dioxide emissions per year.

The advantages of the proposed technology are as follows. The draft in the tower does not depend on the absolute value of the temperature in the greenhouse, but on the temperature difference between the air in it and the air surrounding the pipe on high altitude. Because Solar Tower can work in almost any weather.

In addition, such a tower will continue to generate electrical energy at night, since during the day the soil under the greenhouse will warm up very significantly and will be able to warm the air under the film for a long time.

This power plant will cost about $750 million. The developers do not specify where the funds come from and whether there is already the required amount. But although the construction of the colossus has not yet begun, EnviroMission has already entered into an agreement with the Southern California Public Power Authority to purchase the energy that the Solar Tower will generate.

According to Gizmag, this contract is concluded for 30 years.

Meanwhile, as follows from the estimates of the EnviroMission itself, the solar energy tower will pay for its construction in just 11 years, and this giant will be able to stand for at least 80 years. It's an ambitious goal and a challenge for the engineers designing the record-breaking pipe.

Will the Australians be able to fulfill their plan? Under an agreement with SCPPA, the Arizona tower is to start supplying electricity to the grid in the first half of 2015.