Solar Downdraft Wind Tower Planned in Arizona
The concept of a solar wind tower is not new. The German government, who else, was the first to finance a project and a small-scale experimental model of a solar draft tower was built near Manzanares, Ciudad Real, near Madrid, Spain, completed as early as in 1981/1982, see picture above. The demonstration project operated successfully for eight years before it was ‘decommissioned’, which sounds better than “after the 195m tower collapsed in 1989″. Output: a meager 50 kW, which is the equivalent of a small winturbine, with 20m rotor diameter and 30 m tower. Peanuts.
In 1982, a small-scale experimental model of a solar draft tower was built in Manzanares, Ciudad Real, 150 km south of Madrid, Spain. The power plant operated for approximately eight years. The tower’s guy-wires were not protected against corrosion and failed due to rust and storm winds. The tower blew over and was decommissioned in 1989.
Inexpensive materials were used in order to evaluate their performance. The solar tower was built of iron plating only 1.25 millimetres (0.049 in) thick under the direction of a German engineer, Jörg Schlaich. The project was funded by the German government. The chimney had a height of 195 metres (640 ft) and a diameter of 10 metres (33 ft) with a collection area (greenhouse) of 46 hectares (110 acres) and a diameter of 244 metres (801 ft), obtaining a maximum power output of about 50 kW. Various materials were used for testing, such as single or double glazing or plastic (which turned out not to be durable enough). One section was used as an actual greenhouse. During its operation, 180 sensors measured inside and outside temperature, humidity and wind speed data was collected on a second-by-second basis. This experiment setup did not sell energy.
Old video of the Manzanares project. Investment volume less than 1 million $ (1981).
As far as we know, the only other serious attempt to test the solar wind tower concept was carried out by the Chinese, who completed a project in 2010 in Wuhai, Inner-Mongolia [map] and is operational since, see picture:
The original ambitions of building a 200 meter tower had to be scaled down to merely 50 meter. Power: up to 4,800 kwh/day, enough for 160 homes. The results are such that plans exist to integrate this concept in high rise buildings. Critics however say that “solar chimneys were impractical because they needed huge amounts of land and produced little power in return.”
[scmp.com] – ‘Solar chimneys’ may help solve China’s energy woes
Meanwhile, a plan exist to build a solar downdraft wind tower in San Luis, Arizona, southwest of Yuma, between the Mexican border and the Colorado River. Height tower: 686 meter (2,250-feet) and if realized, it would be the tallest structure in North America. Date: 2015. Output: 200 MW. The falling winds within the tower can reach speeds that exceed 50 miles per hour. Expected investment volume: $1.5-1.8 billion (7.5 – 9$/Watt, where solar and wind can be installed for ca. 1-2$/Watt). Employment: 2,000 people. Demonstration video:
Editor: are you seriously going to build a 686 high structure to harvest a lousy 200MW? You’re joking, right? Why not install 27 7.5MW windturbines for a quarter of the price?
[smartplanet.com] – 2,625-feet solar power supertower to rise over Arizona
[greenbuildermedia.com] – Solar Wind Tower Could Rival Hoover Dam in Power Output
[wikipedia] – Energy tower (downdraft)
[math.purdue.edu] – The solar chimney
EnviroMission, originally an Australian bureau, promoting a project planned for Texas. The video music is beautiful, much better than the plan itself, we fear, which is mainly, pardon the pun, hot air, no mesmerizing sounds from the shores of the North Sea can change that. We kindly advise the Aussies & Americans creators of the video to stay loyal to their core competence, consisting in identifying beautiful music and combine it with fantastic videos and move into the film business. The fact that the real giants in renewable energy, the Germans and Chinese, have quietly dropped the subject, should be enough warning for you.