There was some Elonex One netbook, for sale at around 200 euros (plus VAT). That's the cheapest I've seen so far, though not much cheaper than the original EeePC (with 7" screen)
I don't - however, I can give some uneducated guesses and a top value for efficiency.
A stationary panel presents a variable surface to sun, by the sine of the angle of the sun from an East view.
This way, the surface, for all day, is the integral of the sine (integral of sine from 0 to pi). This adds up to 2, while the surface of a rectangle (the best efficiency with a tracking panel) would be PI.
However, panels might be less efficient from lateral light, so one must use more than one and a half the panel size with non-tracking panels.
If the tracking system is less than half the panel cost, then tracking panels are cost effective (we're talking about panels that have the same efficiency with lateral light, and tracking systems that work forever).
Based on the angle of the panels in a picture, they are using relatively cheap tracking systems to improve the percentage of light received from Sun.
One reason would be the use of "concentrating" solar arrays (array has a larger surface than the photo elements, and the light is concetrated on them) which lose a lot of performance when not directed at the sun
The other reason would be to greatly improve performance in the morning and in the evening - the performance of even non-concentrating panels might drop by more than the effective surface would suggest (oblique lighting 60 degrees away from best position halves the effective surface, but it might reduce power by more than half)
This might be the reason for spacing them so - when they start producing electricity, their shadows will cover the distance to the next row of panels, without much overlapping.
There is demand for hot water in the hot areas, and there is demand for better thermal protection of the houses too - but good luck convincing government to invest $400 millions in house-based solar heaters, or whatever, as opposed to a centralized power plant that will benefit a big corporation.
Even kites fly in those columns of hot air, so even more people love them. On the other side, the air that flows inside a vertically-stratified cloud move very very fast, and flying below such a cloud can move you very high
That solar chimney plant might need no more supervision than what the big wind turbines need. What was the unit cost, running cost, maintenance cost on that nuclear reactor? The solar chimney might cost about half a billion dollars
Again, Nellis Solar Power Plant: Something like that would cost $2bn, shade about a sixth or less of the ground, and generate similar power levels.
As for "decimating the desert": They put a clear roof over. Now, they'll double the efficiency if the ground is blackened. They'll keep the sand dust off if the ground is covered with something solid (sand dust is very abrasive at the speed the blades of the turbines turn).
As for temperatures, they won't be kept at normal, as the efficiency depends on having very very hot air at the base. So, it would be less than annihilating everything, but I don't think it will be much more
Nellis solar power plant in Nevada: 13 MW peak power from 0.22 square miles of land, with sun-tracking PV panels for a cost (in 2007) of $100 millions. That would make a 4 square miles installation able to generate about 250 MW for about $2billion. However, based on what I saw in pictures, their shadows cover less than one quarter of the land so you could increase those 250 MW by a factor of 5 or more (and increase price with the same factor).
So yes, it's about right. And it would only cost 25 times as much for 6 times the power
For the 4 square miles facility envisioned, you would need 1 mile long shafts to put the generators outside the greenhouse.
If there is waste heat to be rid of, the solar chimney could have a smaller greenhouse for the same power, or the same greenhouse for more power.
Only the high performance (and very costly) PV solutions (with some kind of integral reflector/refractor/whatever) must be pointed directly at the sun, or their efficiency drops considerably. Many PV systems are stationary, mounted on roofs.
I really doubt my 15 years car could generate the 66 MW it's supposed to produce.
200 MW is peak power - assuming they can make it work at peak power for 6 hours a day and half power for another 6 hours, that would make about 1800 MWh per day (or some 650 GWh a year)
Yes, most of the places with first wold lifestyle suffer from too many old people. Look at Japan, look at Europe. There will soon be one working man for every man in retirement, if there's not fewer than one already.
We're not constrained by space, and a lower efficiency solar chimney might be cheaper in the long run than a higher efficiency, same power, solar tower or solar cells or whatever.
The lower the efficiency, the more bulky the plant tends to be - but not always more expensive. Coal plants that burn powdered coal might be more efficient than those that burn coal "as mined", but they are more expensive in construction and maintenance costs.
Lots of mirrors that must focus perfectly on the tower, day after day, season after season. A big part of the cost of such a plant is in the actuators for the mirrors. Also, you need expensive materials in the steam turbines, heating elements (high pressure heating elements, I mean), pumps for hot liquids and so on.
As for the solar chimney, once you build it, all you have to care about are some wind turbines that work in not very hot conditions (hotter than water's boiling point, probably, though)
What is the concentration of uranium in uranium mined? For coal it's close to 100%.
The big cost is not in mining it, but in refining it to the purity needed for reactors. Remember the huge effort for creating enough nuclear fuel for the first nuclear bombs?
They will replace the light brown/orange/whatever of the desert with something black, to trap more heat. This will double the heat that stays on Earth (and is not reflected to space)
But in the South they don't need hot water, they need electricity for air conditioning...
Yes, there are plenty of places to invest more wisely money. On the other side, if what they want is electricity, solar hot water systems won't cut it.
The photovoltaics would then transform in electricity some part of the solar power that would become heat. Also, they would work at higher temperatures.
Not the best idea
How much will cost 4 square miles of solar panels? This solar chimney might be a tenth the efficiency and one percent the cost, and it will pull ahead.
Slashdot Mirror
Melted fuel flowed down from the fission chamber (that burst open). If that's not a meltdown, I don't know what it is:
http://en.wikipedia.org/wiki/File:Pictureofchernobyllavaflow.jpg
on the Wikipedia page on Chernobyl
There was some Elonex One netbook, for sale at around 200 euros (plus VAT). That's the cheapest I've seen so far, though not much cheaper than the original EeePC (with 7" screen)
Since the days of the Sinclair Spectrum Z-80 computers, the joysticks have accrued what seems to be a keyboard (from two buttons to 15+ buttons).
I don't - however, I can give some uneducated guesses and a top value for efficiency.
A stationary panel presents a variable surface to sun, by the sine of the angle of the sun from an East view.
This way, the surface, for all day, is the integral of the sine (integral of sine from 0 to pi). This adds up to 2, while the surface of a rectangle (the best efficiency with a tracking panel) would be PI.
However, panels might be less efficient from lateral light, so one must use more than one and a half the panel size with non-tracking panels.
If the tracking system is less than half the panel cost, then tracking panels are cost effective (we're talking about panels that have the same efficiency with lateral light, and tracking systems that work forever).
Based on the angle of the panels in a picture, they are using relatively cheap tracking systems to improve the percentage of light received from Sun.
One reason would be the use of "concentrating" solar arrays (array has a larger surface than the photo elements, and the light is concetrated on them) which lose a lot of performance when not directed at the sun
The other reason would be to greatly improve performance in the morning and in the evening - the performance of even non-concentrating panels might drop by more than the effective surface would suggest (oblique lighting 60 degrees away from best position halves the effective surface, but it might reduce power by more than half)
This might be the reason for spacing them so - when they start producing electricity, their shadows will cover the distance to the next row of panels, without much overlapping.
There is demand for hot water in the hot areas, and there is demand for better thermal protection of the houses too - but good luck convincing government to invest $400 millions in house-based solar heaters, or whatever, as opposed to a centralized power plant that will benefit a big corporation.
Even kites fly in those columns of hot air, so even more people love them. On the other side, the air that flows inside a vertically-stratified cloud move very very fast, and flying below such a cloud can move you very high
There is a wikipedia page about the Nellis Solar Power Plant - this isn't a figment of my imagination, and is not theoretical
That solar chimney plant might need no more supervision than what the big wind turbines need. What was the unit cost, running cost, maintenance cost on that nuclear reactor? The solar chimney might cost about half a billion dollars
Hang gliders avoid clouds, and even civilian pilots avoid them
Again, Nellis Solar Power Plant:
Something like that would cost $2bn, shade about a sixth or less of the ground, and generate similar power levels.
As for "decimating the desert":
They put a clear roof over. Now, they'll double the efficiency if the ground is blackened. They'll keep the sand dust off if the ground is covered with something solid (sand dust is very abrasive at the speed the blades of the turbines turn).
As for temperatures, they won't be kept at normal, as the efficiency depends on having very very hot air at the base. So, it would be less than annihilating everything, but I don't think it will be much more
Nellis solar power plant in Nevada:
13 MW peak power from 0.22 square miles of land, with sun-tracking PV panels for a cost (in 2007) of $100 millions. That would make a 4 square miles installation able to generate about 250 MW for about $2billion.
However, based on what I saw in pictures, their shadows cover less than one quarter of the land so you could increase those 250 MW by a factor of 5 or more (and increase price with the same factor).
So yes, it's about right. And it would only cost 25 times as much for 6 times the power
For the 4 square miles facility envisioned, you would need 1 mile long shafts to put the generators outside the greenhouse.
If there is waste heat to be rid of, the solar chimney could have a smaller greenhouse for the same power, or the same greenhouse for more power.
Only the high performance (and very costly) PV solutions (with some kind of integral reflector/refractor/whatever) must be pointed directly at the sun, or their efficiency drops considerably. Many PV systems are stationary, mounted on roofs.
I really doubt my 15 years car could generate the 66 MW it's supposed to produce.
200 MW is peak power - assuming they can make it work at peak power for 6 hours a day and half power for another 6 hours, that would make about 1800 MWh per day (or some 650 GWh a year)
Yes, most of the places with first wold lifestyle suffer from too many old people. Look at Japan, look at Europe. There will soon be one working man for every man in retirement, if there's not fewer than one already.
We're not constrained by space, and a lower efficiency solar chimney might be cheaper in the long run than a higher efficiency, same power, solar tower or solar cells or whatever.
The lower the efficiency, the more bulky the plant tends to be - but not always more expensive. Coal plants that burn powdered coal might be more efficient than those that burn coal "as mined", but they are more expensive in construction and maintenance costs.
Lots of mirrors that must focus perfectly on the tower, day after day, season after season. A big part of the cost of such a plant is in the actuators for the mirrors. Also, you need expensive materials in the steam turbines, heating elements (high pressure heating elements, I mean), pumps for hot liquids and so on.
As for the solar chimney, once you build it, all you have to care about are some wind turbines that work in not very hot conditions (hotter than water's boiling point, probably, though)
What is the concentration of uranium in uranium mined? For coal it's close to 100%.
The big cost is not in mining it, but in refining it to the purity needed for reactors. Remember the huge effort for creating enough nuclear fuel for the first nuclear bombs?
Radio antennas do not release the energy as heat - or at least, not heat that remains on Earth but energy that is beamed outside Earth
They will replace the light brown/orange/whatever of the desert with something black, to trap more heat. This will double the heat that stays on Earth (and is not reflected to space)
But in the South they don't need hot water, they need electricity for air conditioning...
Yes, there are plenty of places to invest more wisely money. On the other side, if what they want is electricity, solar hot water systems won't cut it.
The photovoltaics would then transform in electricity some part of the solar power that would become heat. Also, they would work at higher temperatures.
Not the best idea
How much will cost 4 square miles of solar panels? This solar chimney might be a tenth the efficiency and one percent the cost, and it will pull ahead.
Each company has legal and financial teams of hundreds/thousands which are dedicated to "legalize" those "subsidies"