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The phenomenon that is considered as sensational and revolutionary today still is actually really simple and taught to children in high school already: Warm air rises.
That is also what popular scientific writer Hans Günther came up with in 1931 when he described his vision of how energy would be produced in one hundred years in the German magazine "Kosmos". He suggested vertically attaching a pipe to a steep face and catching the rising warm air with it and thus using the thermal phenomenon. For decades Günther's idea sank into oblivion until the German architect Prof. Dr. Jörg Schlaich built a prototype powerplant in Spain he had planned out by himself. The more sophisticated principle: a huge glasshouse open on the sides with a tall hollow tower in its middle. The sun heats up the air through the glass of the "greenhouse" and then the warm air comes together in the centre of the tower. With a speed of approximately 50 km/h it then rises up like in a chimney and actuates a turbine which produces energy. The very same phenomenon that causes paragliders and hang gliders to cheer can be witnessed on sunny days near mountainsides and steep rock faces: Thermodynamics! Warm lighter air particles don't only cause lukewarm updrafts but also a powerful suction and finally cool down to sink back to the ground.
A simple network of hoses makes sure that energy is also produced in the glasshouse at night when the sun isn't shining. The heat of the day is captured in the water and released at night to heat up the cooling night air. And the whole process starts anew.
The solar-thermic tower that will be built in Victoria, one of Australia's hottest states, with a budget of 440 million Euros and the blessing of industrial minister Macfarlane will not only be the first economic solar tower in the world but also be the highest building of our entire planet with its 1000-meter high tower. The area of the greenhouse is 7 square kilometers and the turbine with a 130 meter diameter at the foot of the tower is supposed to produce 650 gigawatt hours of electricity which would be enough to power a town with 200.000 inhabitants.
Prof. Schlaich said in our interview: "It is obvious that a solar tower with concrete, glass and steel as raw materials is cheaper than infinite rows of expensive solar cells. However building such a plant only makes sense in inhospitable places like deserts where there is sufficient sun and especially space without having to destroy the environment. Of course approaching such a cost-intensive project like Austria's hydroelectric power plant requires farsightedness. One only becomes aware of the inestimable benefit after years and years, when the costs are won back and the solar tower runs by itself without coal, oil or uranium and especially without producing tons of pollutants."
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