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Solar Power Put to Good Use
Current Shunts writes "Teams from all over the U.S. and Canada will be competing this summer over a 2,500 mile course from Austin, Texas in the United States to Calgary Alberta Canada for the 2005 North American Solar Challenge. The purpose of this event is to promote renewable energy technologies, integrate science and engineering disciplines, and give competitors an opportunity to showcase their technical and creative abilities." At the same time, zestyalbino writes "Construction on the world's largest solar tower [RMIT] may begin next year in Mildura, Australia. In a nutshell, "An ever present large mass of air under an expansive transparent collector (seven kilometres in diameter) is heated by solar radiation (greenhouse effect) providing a continuous flow of hot air to drive electricity generating turbines located around the base of the one-kilometre tall central tower." There's also an article on Wired."
"The Solar Tower concept operates on a simple rule of physics - hot air rises" The Solar Tower project uses hot air generated in a big green house to spin a wind turbine. It looks like a cool idea if you ask me. Aneway, the point is, not every form of solar power uses photovoltaic cells. But you do have a point, the chemical cost for photovoltaics right now is very high.
We are the Borg...
My father invented and patented this idea; the US patent, granted in 1981, was originally filed in 1975. He never got a dime out of it, and the patents, in Canada, Australia, Israel, and the US, have all expired. I guess he was ahead of his time. More information here.
Here is a 10MB torrent of an Animation from the acticle.
SolarTower-Metric-Short.mpg.torrent...runs from Darwin to Adelaide over 3000km in the Australian Outback. http://www.wsc.org.au/
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What chemical costs might those be? For solar cells, they're quite low -- nothing at all like integrated circuits, if that's what you had in mind. Last I looked, the only chemical waste that the larger plants in the US produced in large enough quantities to report to the EPA was a bit of sodium hydroxide. The plants are larger now than they were then, but the only other chemicals that are commonly used in significant quantities are glycol, sometimes hydrofluoric acid, phosphoric acid (or in some plants POCl3), silane, aluminum, silver, and silicone. Solvents are used only in very small quantities.
Chemical safety specialists generally regard silane as the most problematic chemical in a PV plant, and even then it is more of an occupational safety issue than a pollution or "chemical cost" issue.
"Besides, the Australian system looks as if it is more reflectors."
If you'd even read the article summary, you'd have noticed that it is in fact a huge greenhouse channelling hot air into a tall funnel with a turbine mounted in it...no reflectors whatsoever, and the ground underneath is still usable.
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Let's just ignore the chemical costs of making solar collectors
Which don't approach the cost of the power that they generate unless you factor in the time for return on profit compared to other forms of power.
Hu and White in 1983 published the results of a study on Solarex panels; energy payback was 6.4 years, with panels that had 12.4% efficiency. This was from 1977 cells. Nowadays, the numbers are generally 1-3 years. Amorphous pay back the fastest - some even under 1 year.
The rest of the time, they're just generating power. Dollar payback time is usually 4-10 years.
Don't take a knife to a gunfight, or even a knife to a knife fight. Take a gun to a knife fight.
"At temperatures up to 70 C beneath the greenhouse, nothing is going to grow there and soil moisture will be lost rapidly."
.au, at least). Salt is carried to the surface by the water table rising. Anything that causes a lowering of the water table prevents further salination, so accellerated surface evaporation is as good as revegitation. Again, this has all been taken into account.
The highest temperatures will be in the center of the array, and closest to the ceiling. The temerature at ground level and around the rim will be lower, thanks to the very convective effect that makes the whole proposition feasible, but by how much will depend on the ceiling height. Remember thermal gradients; it may not be possible to use the entire area, but a good portion of it will never come close to70 C. I have to point out that growing plants under it is actually part of the proposal, it isn't my idea. If you don't think it's possible, tell the people planning it, I'm sure they'll appreciate the advice.
"It may be possible to use this land to extract salts for industrial use"
Not really, it's common sodium chloride, and much more readily available in commercially attractive deposits elsewhere; desalination plants along the nearby Murray River, for example.
"From this I gather that, as a first approximation, energy expended to evaporate water will be lost"
Two points: (1) Mildura receives little rainfall (irrigation is vital), so surface water isn't as much of an issue as you might think, and (2) this has probably been included in the effciency calculations.
"I doubt that a large expanse of even more highly salinated land is going to contribute much to the local environment."
You don't understand the mechanism behind land salination (in
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Actually, I believe that myth was disproven by the guys on the Discovery Channel's Mythbusters.
p is ode/episode_03.html
Basically, they tried to replicate the experiment, using modern mirrors and tools, and failed. They saw it was pretty much impossible to align the mirrors just right, or to properly aim all the mirrors properly, even with today's tools. They deemed it pretty much impossible for however many years ago it was.
According to the DC website, it was episode 16--sadly, they only have a teaser, no synopsis.
http://dsc.discovery.com/fansites/mythbusters/e
As for making a big deal about the land area - desert is cheap. Even western Victoria has desert, and that is where they are putting it.
It's a pilot plant, funny how for nuclear trolls a small pebble bed pilot plant is serious base capacity, and a slightly larger solar thermal pilot plant is not worth building.Electricity gets mentioned, so the nuclear trolls appear. This one true energy fanaticism is not realistic for any form of electricity generation.
The solar cars can actually go very fast but the speed is not limited by the technology but by the rules. The cars go over the same roads that every one else travels every day. It would not be safe to have a solar car speeding down a busy interstate at 90MPH.
I was a member of the Iowa State University Solar Car Team and would hear stories of the previous races and how the rules have changed. In the first race the rules did not dictate a maximum speed so the drivers would go as fast as they could. I've heard of drivers waving a handful of speeding tickets as they cross the daily checkpoints. Later rules penalized teams that broke the speed limit. When the 55MPH speed limit on interstate highways was lifted by federal law the rules added a 55MPH limit to the cars regardless of the posted limits. I used to joke that it's the only race I've heard of with a speed limit.
The solar car race is not as much of a race as it is a marathon, a competition, or an experiment. Just getting the car to complete the daily checkpoints can be a challenge if the wind isn't blowing right, or their are too many clouds (or, oddly enough, not enough clouds). I don't know what the rules are like right now but the first person to cross the finish line is not always the winner. Times are tallied up over the days of the race, penalties are added up and then the winner is announced.
One thing that we'd always have to tell people when showing off the car is that is unlikely that anyone would ever drive a solar car as a means of daily conveyance. The power that one can derive from the sun is unreliable, and currently expensive. This is more of a race of electric cars than anything. A solar car is a serial electric hybrid, which means the power train is completely electric but the batteries are charged by photovoltaic cells. The cars are more an engineering challenge than a proof of concept.
If you really want to see electric cars race there are better places to do so. I've heard of electric dragsters that can do as well or better than their internal combustion cousins. Don't expect to be impressed there either, they don't rumble and roar, the don't belch out flames and fumes, they simply get from start to finish in a very short amount of time.
So hey - we can afford to build ridiculous 1KM high towers while we rape all you other shmucks by selling you Uranium.
but I must remind them that it wasn't all of Chenobyl which failed - just one unit, the other five kept running and are still running today
- 15/timeline.shtml
"The Chernobyl plant was closed in December 2000...."
http://www.iaea.org/NewsCenter/Features/Chernobyl