It's been proposed and implemented a dozen times or more for linux - Andrew Clausen and I implemented one years ago called 'upstart', Rusty Russell presented one at linuxconf.au-2001 in Sydney, and showed how to preroll the block cache to reduce disk time.
No doubt it was suggested back when sysV boot scripts were first invented.
That article isn't "The Answer", it is merely one person's attempt to put numerical values on the current cost of things.
The problem is, you (and the quoted article) are talking about the correct thing to do if you were a small player in a big market, say a company trying to work out how to pay for running its computers and lights this year. In that case I agree that PV is probably not a great plan (unless you expect some other gain from it, such as publicity, or it would mitigate the cost of putting in new wiring).
What I am talking about is if you were a major player, such as a multinational or a government. In that case your purchasing habits will affect the market. If PV cells became something you could paint on every surface for comparable cost to exterior paint, then PV would save money. If PV cells could be incorporated into the tinting in windows and offset the airconditioning bills twice then PVs would save money. Remember that when large scale uses of technology happen, the economics change dramatically (I can fly from Australia to Europe for a few weeks of income - because the aeroplane industry got big).
I expect that you drive and probably own a car. Yet there are numerous articles showing that a bike is the better economic choice. Similarly, bricks are one of the most expensive housing materials, yet I bet your house is made of bricks. Basic costing analysis cannot cover all of the externalised costs with a technology, and that article made very little attempt to measure the externalised costs of coal over PV.
Seriously, 87km^2 isn't a very large area. I expect that Melbourne alone would have that much roof area. Energy demand patterns can change if the pricing changes. We don't need to implement a pure PV energy system to make a difference.
So stop being wrongly cynical and try to think in Keynesian terms of changing the economics to achieve wothwhile goals.
Most of your arguments are of the form "If they were efficient they would be cheaper." That isn't really answering my question as to why they are no suitable now.
Lets see:
"The smaller the territory on which there are solar panels the smaller the maintenance cost."
Sure, but the maintenance of solar panels is already far less than any other form of energy, that's why they are used in self-contained RPS and satelites.
"Also, there are losses when you transfer the power to the end user."
This one is a puzzler, I can't see how that is even slightly relevant. You get losses when you move electricity around no matter how it is generated.
"AFAIK, solar panels make DC which you have to convert to AC. Then there is loss when you transmit this energy via power lines, etc."
Actually, it more efficient to transmit DC, but in any case the preferred method for generating large scale solar power would be to have a small inverter on each panel. The whole thing would be manufactured ready to install, with a 240VAC plug ready to connect to existing systems. (This is here and now)
"If you use the DC to electolyze hydrogen there is a loss in the electrolysis process...."
Totally irrelevant. Incidently, you can electrolyze more 100% H from water if you supply heat to the process. This heat can be waste heat. Recent experiments have even converted sunlight directly to hydrogen in a single step.
"So, in the end, the end user will receive about 10%-15% out of the 25% produced by the solar panels... "
Compared with coal with a solar efficiency of what, 0.001%? Even if you discount the construction of a coal power station, and give the coal away for free, brown coal electricity in Victoria still costs about 1c/kW, which is damn close to the expected return on a solar panel.
"Finally, there are not enough raw materials (mostly silicon) on Earth to make enough solar panels which are only 25% efficient to cover the energy needs of Earth."
This one is insane. Wikipedia gives silicon as 25% of the Earth's crust. We have enough silicon to cover the earth entirely in solar panels (even enough dopants!) and still make scarcely a dent in the available silicon. If you are so concerned about wasting silicon, perhaps you should sell your computer?
The air is 22% Oxygen. It is quite simple to extract the oxygen out of the air (many diesel engines use oxygen membranes to reduce particulate emmisions).
Can you explain why we need very efficient solar panels? (currently the state of the art is around 25% efficient, so you mean for say 3* more power per square meter?) Doesn't seem very convincing.
I think the only real issue is actually using the stuff we already have. I expect that if solar panels were being installed in megawatt installations across cities the price would fall quite quickly.
Put the plasma gun in orbit around earth, send forth plasma from one side of the orbit over say 45 degrees, wait until you get to the other side of the planet, repeat. That way you counter the momentum by applying it in opposite directions.
(to smooth out the plasma supply, put a constellation of plasma guns around the planet.)
Having said that, I think the idea is unworkable due to the vast distances between Earth and Mars - the plasma is going to be pushed around by the solar wind which will make it very hard to stay on target.
I think something like M2P2 or solar sails are going to be cheaper and give much greater impulse.
Don't forget that another byproduct of fusion is neutrons. These get lodged in the containment system and turn stable isotopes into heavier, possibly unstable (radioactive) isotopes. The elements in question could be strontium or potassium, both of which can easily end up in the food chain.
Another serious problem is metal embrittlement where strong containers become weaker as the neutrons rearrange the crystal structure. This makes it hard to run a reactor continuously, thus producing lots of radioactive waste from the replacement of parts (pipes, shielding etc). I suspect that until embrittlement gets 'solved' we're going to find both fusion and fission unecconomical.
Having said that, I agree that the amount of waste is probably entirely dwarfed by the amount of crap produced by burning coal or oil.
The contrast can't be infinite unless the off LEDs reflect no light either. Otherwise the contrast of printed paper would be 0 (no light emitted for either black or white).
In my case it's on a laptop. I've set noatime on all the partitions, and I don't have a swap partition. Yet it still randomly wakes up. Any other ideas?
The problem with this, at least on my Debian system, is that 5 seconds later something touches the disk again, and everything spins up. I've turned off atime, and suspended mozilla, to no effect. Something really likes to check the disk.
which say that food aid is unhelpful. Of course, you can find just as many that say it is. So I haven't learnt anything new from your post and I now will be less likely to care about anything that happens in ethiopia - once I cared, but was told to piss off and stop being patronising.
People seem to bring this up everytime people talk about free software in 'third world' (really, poor, developing) countries. The reality is that putting your $10000 into posting food to ethiopians will not have the desired effect - the food will never get to the people who need it, rather it will be siphoned off to raise armies.
The same goes for 'plumbing' and other similar suggestions. The ethiopians already have 'open plumbing technology' in the form of buckets. I presume you were actually refering to the provision of fresh water? Well in that case the problem is explaining to people how the state of the art works. We have to be careful providing our western solutions to developing countries as many things require complex supply chains to remain operational for many years - we may be able to build computers for $100, but we rely on a vast supply chain to keep everything working. Traditional societies have already solved these problems in the last 10000 years, the techniques just need to be implemented. And that is hard to do when your oral history keeps getting broken with machine guns.
The reality is that without education and without stopping wars you are never going to help people in these countries. And one of the cheapest methods to start this change is to provide a way for villages to communicate at their own pace.
Free software can provide this opportunity and empower people to talk with others and develop their own solutions to their problems.
I thought it was not the volume, but the fineness - comestic silca is very fine and can lift from the surface of bubbling liquids. These particles are too fine to easily separate, but they don't affect the operation of an H2SO4 fuel cell. Normal sand can be separated out using gravity.
A friend of mine works in the fuel cell industry and he said that sulphuric acid fuel cells are better for waste-water methane -> electricity conversion as the very fine silca that gets into the sewers from cosmetics tends to erode moving parts quite quickly.
Try out inkscape sometime and tell us what to improve. We have quite a few developers using MacOSX so it should run quite well. Can you tell us anything you would particularly miss from freehand? We are approaching a feature freeze and should have a new version out by tuesday.
Personally, I run Debian on my powerbook, because I feel that by not committing 100% to sharing free software I am breaking my social contract - I am good at finding and fixing bugs in free software and I think that that talent would be wasted if I were to work on a propriatary platform.
Actually, C + O2 => CO2 is quite a good source of energy, it is the standard source of energy for steel production, for example.
If you want to extract more hydrogen from this carbon, you can convert carbon and water into methane and carbon monoxide by 'burning' the carbon in steam. This is the basis of 'water gas', the original town gas. Further reactions can reduce more water into methane, then the methane into hydrogen.
Another interesting energy store is Boron as covered in this article:
On further thought, you're right. This is how those cool shelters work out in central Australia. They have a big sail made of white fabric which reflects the sun from the north, allowing the area underneath to radiate heat out to the south. Nifty! You don't need clever paint, just a big sail.
Interestingly enough, my office building is built with exactly this design. The air is close to hermetically sealed(double glazed, airlock entry etc), and the engineers spent a few weeks tweeking the system to make sure that enough fresh air is brought in to balance the CO2 load.
Efficient methods for moving heat from one gas stream (and even water vapour) exist, they are called adiabatic wheels http://www.novelaire.com/descool.html
I spoke with the air conditioning engineers when they built our building and they claimed that limited inflow air cooling systems are about half the energy consumption compared against a fresh only system.
In hot humid area, such as mentioned in the original post, the large part of airconditioning costs come from dehumidifying the incoming air. It turns out much cheaper to dehumidify the already cooled air inside the building rather than starting from scratch with fresh air.
It is certainly worthwhile in Australia to use these techniques - it is now standard operating practice. I agree it might be a bad choice for housing, perhaps because people don't want to spend lots of time tweeking their system.
I think a 110% idiot would be someone who opens their mouth before even bothering to do a google search, thus absorbing some idiocy from the surrounding slashdot air.
I don't think this works for cooling. The problem is that the sky isn't space. It isn't much cooler than here. This idea is sort of the same as the frozen water on a clear night idea. It doesn't happen during the day. Why don't you set up an experiment by putting a thermometer in an insulating tube (probably can be done using foil!) and point it at the sky - see if the temp drops measureably.
Tell me if you get anything to happen - I couldn't measure a change in temp.
Reducing the amount of heat that gets into a building will reduce the airconditioning costs. This is more important for cooling, as cooling systems are limited to less than 100% efficient (whereas heating can well over 100% efficient).
Imagine if your house were perfectly insulated, then you would only need to suck out the heat added by the things inside it (200W per person, another 200W per computer).
As far as I can see the glass is supposed to not absorb the 80GW of light, yet the hydrogen is. Is the author claiming that silca glass absorbs less photons than hydrogen? If it absorbed only 0.01% of the total photons it would still get 8MW of heat, which is going to be quite hard to keep cool. For comparison, the optics used in cameras absorb 0.1% of the incoming photons.
On the other hand, hydrogen doesn't strike me as particularly absorbent. I thought it was mostly transparent except for a few frequencies (the hydrogen bands). As the gas reactor is acting as a purely blackbody radiator it's going to emit in a classical SB distribution, which will mean that most photons are going to just bounce around until they get absorbed by the mirror or glass.
So the obvious problem to me (and let's face it, I'm not a rocket scientist..) is that you have an 'impedance mismatch' between your energy source and your energy sink.
Slashdot Mirror
It's been proposed and implemented a dozen times or more for linux - Andrew Clausen and I implemented one years ago called 'upstart', Rusty Russell presented one at linuxconf.au-2001 in Sydney, and showed how to preroll the block cache to reduce disk time.
No doubt it was suggested back when sysV boot scripts were first invented.
Until B == 0.
try:
A = A + B
B = A - B
A = A - B
(but that's just xor with some superfluous carrying)
That article isn't "The Answer", it is merely one person's attempt to put numerical values on the current cost of things.
The problem is, you (and the quoted article) are talking about the correct thing to do if you were a small player in a big market, say a company trying to work out how to pay for running its computers and lights this year. In that case I agree that PV is probably not a great plan (unless you expect some other gain from it, such as publicity, or it would mitigate the cost of putting in new wiring).
What I am talking about is if you were a major player, such as a multinational or a government. In that case your purchasing habits will affect the market. If PV cells became something you could paint on every surface for comparable cost to exterior paint, then PV would save money. If PV cells could be incorporated into the tinting in windows and offset the airconditioning bills twice then PVs would save money. Remember that when large scale uses of technology happen, the economics change dramatically (I can fly from Australia to Europe for a few weeks of income - because the aeroplane industry got big).
I expect that you drive and probably own a car. Yet there are numerous articles showing that a bike is the better economic choice. Similarly, bricks are one of the most expensive housing materials, yet I bet your house is made of bricks. Basic costing analysis cannot cover all of the externalised costs with a technology, and that article made very little attempt to measure the externalised costs of coal over PV.
Seriously, 87km^2 isn't a very large area. I expect that Melbourne alone would have that much roof area. Energy demand patterns can change if the pricing changes. We don't need to implement a pure PV energy system to make a difference.
So stop being wrongly cynical and try to think in Keynesian terms of changing the economics to achieve wothwhile goals.
Most of your arguments are of the form "If they were efficient they would be cheaper." That isn't really answering my question as to why they are no suitable now.
Lets see:
"The smaller the territory on which there are solar panels the smaller the maintenance cost."
Sure, but the maintenance of solar panels is already far less than any other form of energy, that's why they are used in self-contained RPS and satelites.
"Also, there are losses when you transfer the power to the end user."
This one is a puzzler, I can't see how that is even slightly relevant. You get losses when you move electricity around no matter how it is generated.
"AFAIK, solar panels make DC which you have to convert to AC. Then there is loss when you transmit this energy via power lines, etc."
Actually, it more efficient to transmit DC, but in any case the preferred method for generating large scale solar power would be to have a small inverter on each panel. The whole thing would be manufactured ready to install, with a 240VAC plug ready to connect to existing systems. (This is here and now)
"If you use the DC to electolyze hydrogen there is a loss in the electrolysis process...."
Totally irrelevant. Incidently, you can electrolyze more 100% H from water if you supply heat to the process. This heat can be waste heat. Recent experiments have even converted sunlight directly to hydrogen in a single step.
"So, in the end, the end user will receive about 10%-15% out of the 25% produced by the solar panels... "
Compared with coal with a solar efficiency of what, 0.001%? Even if you discount the construction of a coal power station, and give the coal away for free, brown coal electricity in Victoria still costs about 1c/kW, which is damn close to the expected return on a solar panel.
"Finally, there are not enough raw materials (mostly silicon) on Earth to make enough solar panels which are only 25% efficient to cover the energy needs of Earth."
This one is insane. Wikipedia gives silicon as 25% of the Earth's crust. We have enough silicon to cover the earth entirely in solar panels (even enough dopants!) and still make scarcely a dent in the available silicon. If you are so concerned about wasting silicon, perhaps you should sell your computer?
The air is 22% Oxygen. It is quite simple to extract the oxygen out of the air (many diesel engines use oxygen membranes to reduce particulate emmisions).
RTFA.
Can you explain why we need very efficient solar panels? (currently the state of the art is around 25% efficient, so you mean for say 3* more power per square meter?) Doesn't seem very convincing.
I think the only real issue is actually using the stuff we already have. I expect that if solar panels were being installed in megawatt installations across cities the price would fall quite quickly.
Put the plasma gun in orbit around earth, send forth plasma from one side of the orbit over say 45 degrees, wait until you get to the other side of the planet, repeat. That way you counter the momentum by applying it in opposite directions.
(to smooth out the plasma supply, put a constellation of plasma guns around the planet.)
Having said that, I think the idea is unworkable due to the vast distances between Earth and Mars - the plasma is going to be pushed around by the solar wind which will make it very hard to stay on target.
I think something like M2P2 or solar sails are going to be cheaper and give much greater impulse.
One thing I can't convince any of the gecko based browsers to do is render to pngs directly. This makes them useless for my work.
Don't forget that another byproduct of fusion is neutrons. These get lodged in the containment system and turn stable isotopes into heavier, possibly unstable (radioactive) isotopes. The elements in question could be strontium or potassium, both of which can easily end up in the food chain.
Another serious problem is metal embrittlement where strong containers become weaker as the neutrons rearrange the crystal structure. This makes it hard to run a reactor continuously, thus producing lots of radioactive waste from the replacement of parts (pipes, shielding etc). I suspect that until embrittlement gets 'solved' we're going to find both fusion and fission unecconomical.
Having said that, I agree that the amount of waste is probably entirely dwarfed by the amount of crap produced by burning coal or oil.
The contrast can't be infinite unless the off LEDs reflect no light either. Otherwise the contrast of printed paper would be 0 (no light emitted for either black or white).
This "11,000-gallon tanker plane pours 'too much water,'". I guess 24,000 gallons (90000L) is not too much though...
In my case it's on a laptop. I've set noatime on all the partitions, and I don't have a swap partition. Yet it still randomly wakes up. Any other ideas?
The problem with this, at least on my Debian system, is that 5 seconds later something touches the disk again, and everything spins up. I've turned off atime, and suspended mozilla, to no effect. Something really likes to check the disk.
Well I know I shouldn't respond to trolls, but if anyone is being patronising here, it is you.
d 19 d4c85256beb0051bddc?OpenDocument
Rather than attacking my post without adding any further information you could try presenting some facts.
A quick google for 'ethiopia food aid' finds me plenty of articles like
http://www.reliefweb.int/w/rwb.nsf/0/dbe7c656f4
which say that food aid is unhelpful. Of course, you can find just as many that say it is. So I haven't learnt anything new from your post and I now will be less likely to care about anything that happens in ethiopia - once I cared, but was told to piss off and stop being patronising.
You are hurting your cause.
People seem to bring this up everytime people talk about free software in 'third world' (really, poor, developing) countries. The reality is that putting your $10000 into posting food to ethiopians will not have the desired effect - the food will never get to the people who need it, rather it will be siphoned off to raise armies.
The same goes for 'plumbing' and other similar suggestions. The ethiopians already have 'open plumbing technology' in the form of buckets. I presume you were actually refering to the provision of fresh water? Well in that case the problem is explaining to people how the state of the art works. We have to be careful providing our western solutions to developing countries as many things require complex supply chains to remain operational for many years - we may be able to build computers for $100, but we rely on a vast supply chain to keep everything working. Traditional societies have already solved these problems in the last 10000 years, the techniques just need to be implemented. And that is hard to do when your oral history keeps getting broken with machine guns.
The reality is that without education and without stopping wars you are never going to help people in these countries. And one of the cheapest methods to start this change is to provide a way for villages to communicate at their own pace.
Free software can provide this opportunity and empower people to talk with others and develop their own solutions to their problems.
I thought it was not the volume, but the fineness - comestic silca is very fine and can lift from the surface of bubbling liquids. These particles are too fine to easily separate, but they don't affect the operation of an H2SO4 fuel cell. Normal sand can be separated out using gravity.
A friend of mine works in the fuel cell industry and he said that sulphuric acid fuel cells are better for waste-water methane -> electricity conversion as the very fine silca that gets into the sewers from cosmetics tends to erode moving parts quite quickly.
Try out inkscape sometime and tell us what to improve. We have quite a few developers using MacOSX so it should run quite well. Can you tell us anything you would particularly miss from freehand? We are approaching a feature freeze and should have a new version out by tuesday.
Personally, I run Debian on my powerbook, because I feel that by not committing 100% to sharing free software I am breaking my social contract - I am good at finding and fixing bugs in free software and I think that that talent would be wasted if I were to work on a propriatary platform.
Actually, C + O2 => CO2 is quite a good source of energy, it is the standard source of energy for steel production, for example.
If you want to extract more hydrogen from this carbon, you can convert carbon and water into methane and carbon monoxide by 'burning' the carbon in steam. This is the basis of 'water gas', the original town gas. Further reactions can reduce more water into methane, then the methane into hydrogen.
Another interesting energy store is Boron as covered in this article:
http://www.eagle.ca/~gcowan/boron_blast.html
On further thought, you're right. This is how those cool shelters work out in central Australia. They have a big sail made of white fabric which reflects the sun from the north, allowing the area underneath to radiate heat out to the south. Nifty! You don't need clever paint, just a big sail.
Interestingly enough, my office building is built with exactly this design. The air is close to hermetically sealed(double glazed, airlock entry etc), and the engineers spent a few weeks tweeking the system to make sure that enough fresh air is brought in to balance the CO2 load.
Efficient methods for moving heat from one gas stream (and even water vapour) exist, they are called adiabatic wheels
http://www.novelaire.com/descool.html
I spoke with the air conditioning engineers when they built our building and they claimed that limited inflow air cooling systems are about half the energy consumption compared against a fresh only system.
In hot humid area, such as mentioned in the original post, the large part of airconditioning costs come from dehumidifying the incoming air. It turns out much cheaper to dehumidify the already cooled air inside the building rather than starting from scratch with fresh air.
It is certainly worthwhile in Australia to use these techniques - it is now standard operating practice. I agree it might be a bad choice for housing, perhaps because people don't want to spend lots of time tweeking their system.
I think a 110% idiot would be someone who opens their mouth before even bothering to do a google search, thus absorbing some idiocy from the surrounding slashdot air.
9 90 18.htm
http://www.newton.dep.anl.gov/askasci/eng99/eng
I don't think this works for cooling. The problem is that the sky isn't space. It isn't much cooler than here. This idea is sort of the same as the frozen water on a clear night idea. It doesn't happen during the day. Why don't you set up an experiment by putting a thermometer in an insulating tube (probably can be done using foil!) and point it at the sky - see if the temp drops measureably.
Tell me if you get anything to happen - I couldn't measure a change in temp.
Reducing the amount of heat that gets into a building will reduce the airconditioning costs. This is more important for cooling, as cooling systems are limited to less than 100% efficient (whereas heating can well over 100% efficient).
Imagine if your house were perfectly insulated, then you would only need to suck out the heat added by the things inside it (200W per person, another 200W per computer).
As far as I can see the glass is supposed to not absorb the 80GW of light, yet the hydrogen is. Is the author claiming that silca glass absorbs less photons than hydrogen? If it absorbed only 0.01% of the total photons it would still get 8MW of heat, which is going to be quite hard to keep cool. For comparison, the optics used in cameras absorb 0.1% of the incoming photons.
On the other hand, hydrogen doesn't strike me as particularly absorbent. I thought it was mostly transparent except for a few frequencies (the hydrogen bands). As the gas reactor is acting as a purely blackbody radiator it's going to emit in a classical SB distribution, which will mean that most photons are going to just bounce around until they get absorbed by the mirror or glass.
So the obvious problem to me (and let's face it, I'm not a rocket scientist..) is that you have an 'impedance mismatch' between your energy source and your energy sink.