According to the NS article below my
signature block, Australia may soon have the world's tallest man-made tower
(more than twice as tall as any other present-day structure).
Chris Forbes-Ewan
http://www.newscientist.com/news/news.jsp?id=ns99992688
Kilometre-tall power tower approved
14:35 19 August 02
NewScientist.com news service
Plans for a one-kilometre tall "Solar Tower" that would provide clean energy for up to 200,000 homes have been approved by the Australian government. But some environmental campaigners are questioning the practical benefits of the scheme.
The 130 metre-wide tower would produce electricity using currents of air heated by the Sun's rays. The tower itself would be surrounded by a vast greenhouse, seven kilometers across. Hot air inside the greenhouse would be effectively sucked up the tower through turbines at its base.
Heat-storing material inside the greenhouse would continue to heat air during the night.
The massive structure would be more than twice as tall as the Petronas Towers in Kuala Lumpur, and visible from 80 kilometres away.
Australian company
EnviroMission plans to build it in the desert on the border between New
South Wales and Victoria. Australia's federal industry minister put the
£308m project into a fast-track planning process on Thursday.
Fossil fuels
EnviroMission says the building would generate 760 gigawatt-hours of energy per year.
Roger Higman, senior climate campaigner for Friends of the Earth, is concerned that construction costs could outweigh the potential benefits.
"If they're planning to build a truly enormous tower they could use a lot of fossil fuels," Higman told New Scientist. "It's not as if we are short of ways to generate electricity without using fossil fuels."
Higman adds that a conventional wind farm could produce a comparable amount of power without requiring so much construction work.
A smaller 200 metre tall prototype Solar Tower was built by a Spanish and German team in Spain in 1982. If the New South Wales state authority gives approval for the new tower, construction work could begin in 2003 and the structure could be completed by 2005.
Will Knight
Donald Lang added:
The Sydney Morning Herald, and I assume other papers round the continent, had a story last week (14/8/02) on
"Things starting to look up for 1km-high solar tower project."
The idea involves tapping the solar power from a circular area of 3.5km radius. The output is intended to be 200megawatts. It is not clear whether that is the average power on a 24/7 basis, or peak power.
I did some quick calculations and decided that the peak solar energy incident on the surface was about 100 times that output. Guessing frantically, I would divide the peak power by about 3 by shutting it off entirely for 12 hours a day, and diluting it as it gets further from vertical away from noon. I think I would like to see a second [independent] run through my calculations.
I would be interested in the effects of cloud cover, and especially of any clouds induced by the central updraft. Anyone want to bring Gaia into the equation?
With the raw figures one comes up with a cost of $4 per watt of generator capacity. Can anyone enlighten us on comparable figures for other generation methods?
I got the impression that 'opportunity costs' for other uses of the land were being dismissed.
I would be quite interested if someone
is willing to run a series of sweepstakes on such items as the date of
first power generation, the date of achieving the planned peak power, the
actual costs of construction and the costs of continuing operation.
