In the Arizona desert, may appear "solar towers"
The choice of construction site is not accidental. The desert and the sun are inseparable concepts. For a long time the deserts have attracted like a magnet any serious companies that specialize in the field of solar energy. For this reason, the desert in Arizona has not been ignored by well-known "solar" experts. It is in Arizona that EnviroMission specialists are preparing to implement their ambitious idea to develop a powerful solar power station, which is already known as a solar tower.
The idea that underlies the construction of such a structure is quite simple. The sun's rays illuminate and heat a certain part of the surface at the foot of the tower, this area is covered with a special heat insulating material. He himself is a kind of very large greenhouse. The air heated in this "greenhouse" tends to the top, flowing to the only hole in this coating located in the center. It is in this place at the base of the solar tower that the turbines are located, which generate electrical energy at the expense of naturally ascending streams of heated air.
This system is rather difficult to be taken seriously until all the necessary calculations related to the temperature difference have been made and the size of the entire structure has been repeatedly increased. This is exactly what Australian developers have done. If we place such a structure in the desert, where the surface temperature reaches 40 degrees and higher during the day, and also add to this the effect of the artificially created "greenhouse effect", then the air temperature in such a tank will reach 80-90 degrees Celsius. Therefore, it remains only to bring the size of the tank greenhouse around the solar tower to a radius of several hundred meters in order to get a sufficiently large amount of hot air.
It would be useful to increase the height of the solar tower to a height of several hundred meters (with every 100 meters away from the desert surface means a decrease in ambient temperature by 1 degrees Celsius). The greater the temperature difference, the stronger the solar tower will “pull” hot air from the bottom of the storage facility and the greater the amount of energy that turbines can produce.
The advantages of these energy sources lie on the surface:
• Since the solar tower operates due to the temperature difference, and not the absolute temperature, it can continue its work in any weather.
• Since the soil has time to heat up sufficiently in a day, it will have enough residual heat to continue working at night.
• Since the construction of a tower is best suited for a section of hot, dry soil, it is possible to build such a power plant in a more or less useless area right in the middle of the desert.
• The solar tower will require almost no maintenance, except for the rare inspection and / or minor repair of turbines. The tower “just works” from the beginning of its construction until the moment when there are structures that make up the tower.
• Such a power plant does not need raw materials for work - neither uranium, nor coal, nothing but sunlight and air, which is abundant in any desert.
• The solar tower is a completely waste-free production, it does not emit any pollutants into the Earth’s atmosphere, besides warm air; Moreover, certain areas of the "greenhouse" can even be used for its intended purpose for growing various plants in them.
It is worth noting that this technology is quite known, people have been working on such projects for over a century. So, in 1980, Spanish engineers erected a test tower with a height of 256 meters, in which heated air moved through turbines to the top. This tower generated electricity for 7 years, after which it was destroyed by a storm. In this regard, the question of the possibility of implementation rather than the high costs of the project is much more rigid. To produce substantial amounts of electricity, an object of enormous size is needed, and very large structures require very large capital investments.
The cost of construction, estimated by Australian developers, is approximately 750 million dollars. And the energy efficiency of this power plant is expected at the level of 60%, which makes such an object much more reliable and efficient than many other renewable energy sources. In addition, it is known exactly where the energy generated by such a power plant will be directed. Not so long ago, EnviroMission signed a cooperation agreement with the State Energy Agency of Southern California (pre-purchase of electrical energy for a period of 30 years). Based on the results of financial modeling, the construction of such a tower would pay off in just 11 years, and its design is designed for a lifetime of 80 years. If everything goes as planned, the “solar tower” will be able to start the transfer of electricity to the homes of Americans at the beginning of 2015.
Alternative project
But the solar tower already has competitors. This is a power plant with even greater power - up to 1,5 GW. Information about her appeared in RuNet in May 2014. It is reported that the company Clean Wind Energy has already rented a plot of land for the construction of its offspring. In this case, we are also talking about the tower, which would work by creating an artificial wind for generating electricity. Different sources indicate different construction heights, which range from 675 to 900 meters (which is 400 meters above the famous Empire State Building and skyscraper).
At the base of the huge solar tower, 120 of very large turbines will be placed immediately, as well as high-performance pumps designed to drive more than 11 billion liters of circulating water. After commissioning, the solar tower in the desert will have a huge output power, which can be compared with the energy of a high-performance hydroelectric station or wind turbines installed in an area of 40 thousand hectares.
The principle of operation of such an energy tower in 60-s of the twentieth century was put forward by Philip Carlson. However, in those years there were simply no funds that could be allocated for the implementation of such a project. According to available data, the cost of building such a power plant in the Arizona desert is more than 1,5 billion dollars. At the same time, the construction of such a tower can bring American wind energy to a fundamentally new level, and the energy produced by the tower will be the cleanest in the world and will allow the company to make huge money on its production.
The main idea, in contrast to the project of EnviroMission, involves the movement of air not from the bottom up, but from top to bottom. The idea is to spray water at the top of the tower, causing the hot air to cool and rush to the ground. By the time he is at the foot of the tower, his speed should reach 90 km / h, which is ideal conditions for the operation of turbines. Such a tower has its advantages over standard wind and solar energy. The installation will be able to work without problems both day and night, besides, its work does not require continuous wind and sunlight, it doesn’t even need to remove dust, like from solar cells installed in the desert, in order to keep it in working condition. The tower will continue to generate electricity as long as the air remains warm, which is very likely for a hot desert. The production of electricity itself will work from the production of its energy: about 11% of electricity will be spent on pumping water to the very top of the tower, while about ¾ of the water will be collected in its lower part.
Competitors in the form of nuclear power plants
The solar towers have a very real and strong competitor in the form of "good old" nuclear power plants. After a break in 30 years, the US government decided to resume their construction. The administration of the US president has allocated 6,5 billion to build a new nuclear power plant. It is reported that the new nuclear power plant should appear in the state of Georgia, where the Vogtle nuclear power plant is already operating.
In 2010, the US authorities and representatives of the Southern energy company signed an agreement on the construction of new units of this nuclear power plant.
The last, 4, power unit was handed over to the customer in the fall of 2013. Now we are talking about building a new NPP from scratch. The amount allocated for its construction will be divided between Southern Georgia Power, Oglethorpe Power and the municipal authorities of Georgia. It is reported that the first tranche of this project, the company Oglethorpe and Georgia Power received another 19 February 2014 year.
Information sources:
http://www.facepla.net/index.php/the-news/energy-news-mnu/1509-solar-plant
http://radiomaster.ru/reviews/view/208
http://gearmix.ru/archives/11823
http://pronedra.ru/alternative/2014/05/06/energiy-arizona-proekt
http://pronedra.ru/atom/2014/02/19/aes-ssha
Information