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Orbiting Lasers for Hydrogen Power
DerekLyons writes: "Yahoo is carrying a story about a Japanese scientist who plans to use giant orbiting lasers to extract H2 from seawater. The interesting part of the scheme is that design uses solar pumped lasers, which avoid the loss of efficiency (and increased launch weight) from powering the laser with electricity from solar cells. Is the way to finally break the main dilemma of the hydrogen economy? (That it takes more energy to make the hydrogen than you gain in using it.)"
Any government or corporation that puts anything into orbit that could even potentially be used as a weapon is going to face resistance from the entire world. Even if you went into contortions trying to prove that the tool could never be used for military purposes, the media would get ahold of the term "space lasers" and that would be curtains for the idea.
All known solid state laser gain substances have fairly narrowband excitation spectrums. This presents a two fold problem: 1) fairly little power is available in that window (the sun is a blackbody raditator) 2) Energy outside of that window tends to just heat the medium and either cause breakdown or unacceptable thermal lensing.
I've built a solar pumped nd:yvo4 laser, but it was a waste: because of those factors I could have extracted more power and probably energy from a solar electric system.
Without some serious new developments in laser substances with ultra broadband pump inputs, this won't work too well.
We should just use solar panels to generate hydrogen from sea water....
I predict that within 30 minutes, there will be at least two confused posts saying that we should just use solar panels to generate electricity to "crack" the hydrogen from sea water.
...except that, instead of using electrical conversion followed by electrolysis they will use photocatalysis, as described in this Physics World Article, which talks about the implications of a paper published in Nature.
The jist of it, for the link weary, is that by the use of a cunning contrived semiconductor it is possible to arrange the band-gap to be higher that the reduction potential of H2, which allows the production of H2 from the H+ ions that are always present in water.
Early days yet (efficiency is 0.66%, compared with an break-even of 4%), and lifetimes are unknown at the moment. But using solar panels to generate hydrogen should not be rejected out of hand just because the energetics are unfavourable with one particular type of solar cell.
Unlike in the States, big compaines in Japan have a little bit of everything. Mitsubishi makes cars, trains, ships, aircraft, televisions, stereos, agricultural chemicals, food additives, synthetic rubber, molasses, canned foods, textiles, semiconductors ... the list goes on. Any large project in Japan couldn't avoid being associated with a company that also makes cars.
Toronto-area transit rider? Rate your ride.
One problem when comparing plans like this for producing fuel, to other more traditional fuels is that the cost of crude oil or whatever does not reflect the value of the oil.
That is if we had to reproduce the oil rather than just extracting it from the ground we'd probably find other more "green" methods of energy production much less of an investment.
The fact that something that is renewable cost more than something that is irreplaceable is a pointer to the shortcomings of our economic system, not to problems with solar, wind, or other alternative energy sources.
Look, due to the laws of thermodynamics it will ALWAYS take more energy to obtain a resource than to use it. Same applies for oil - once we're out of it, it will be very damn expensive to "make" it.
Sigh. It does NOT currently take more energy to obtain a Oil than to use it. We aren't out of it. That is why renewable energy sources have such a hard time being competitive. It's hard to beat a dense source of energy that's lying around.
a lot of these arguments against renewable energy sources are just rubbish.
Arguements shmarguements. There will be a massive switchover to renewables when the tech improves enough to make it as cheap as oil, or when we start to run out of oil.
Until then, ranting about social change is nothing more than another source of greenhouse gas.
Anyone who's played Civ or MOO etc, knows the way to win the game is to maximize research.
(And to save umpteen people from replying to point out that I just suggested people base national / global policy in a video game, yeah yeah, I know. I still think it's a valid point.)
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A weapon system that's PROFITABLE when not in use! Just imagine how the economic numbers on this thing look better if the DOD covers, say 25% of operating costs for the right to commender it during wartime.
A giant orbital laser that fires to the ground into a giant salt water swimmingpool.
What is the impact of fried birds dropping onto this pool?
What can this concentrated energy do to some of the earths outer layers that are important for climate? Atmosphere, stratosphere, and so on.
Impact on the ozone layer, which is already (by definition, not by human interaction) quite thin and easy to disturb?
What are they going to do with all the Oxygenium? Since the air we breathe consists to more than 70 percent of Nitrogen, not Oxygene, simply freeing large volumes could be problematic. (And can be quite a risk for the installation itself. Think of "no smoking".)
What if a mislead plane happens to fly into the beam? A weather balloon?
Impact on clouds? Hitting them (and the H2O within them) will also split the H2O, and then Ozone will react from the Oxygenium radicals. And: Ozone is only good in exactly the right height over ground. Every Ozone lower than that is poisonous and, in the volumes we're talking about, could lead to quite interesting weather effects within these clouds.
Don't talk about what happens if this cloud of ozone happens to drift over some city. In cities, we usually call this "smog" and try to avoid it.
Sulfur dioxide, raising up in clouds from big cities or other things that burn fuel (oil plants?) is known to react to Sulfur Acid in the athmospere, with the help of the power of sunlight. A while after, we call this "sour rain" or "acid rain". What amount of acid could react if a cloud like this is hit by this _very_ strong artificial sun?
Nice idea, but done by company scientists for company scientists. IMHO, this could cause far too many things to be implemented.
And, remember: "They" are not fiddling with a x square miles big sector of air above their installation. They're fiddling with the atmosphere that is shared by some billion of people. There is hardly a thing like local effects with wind, clouds, and weather. Ask your European friend if he sometimes finds a thin layer of very fine sand outside his house or on his windows. This comes straight from the Sahara desert in Africa. (No, I'm not kidding.)
When the reactor in Tchernobyl went "blob", the radioactive dirt was distributed over half of Europe, 1000s of kilometres, which still ended up with enough dirt to have them throw away every vegetable in their gardens.
And: Science doesn't have any data about what happens to the very highest layers above us when hit by a concentrated stream of energy on a single point that is several times stronger than the strong rays of the real sun around it. It might well cause something or, doing this several months in a row, burn a hole into a layer of gases that we not even know about yet. We Just Don't Know.
Fiddling with this is just stupid.
42. Easy. What is 32 + 8 + 2?
... the Alan Parsons project.
Karma: Professionally Doomed (mostly affected by inability to keep opinions to self)
C'mon people! All I want is some frickin' sharks with lasers on their heads! Is that too much to ask?
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Gort! Klatu Barata Nikto!
Sorry, but you managed to be substantially wrong in parts of BOTH of your points :-)
not to mention the industry mogul's vested interest
You keep hearing this ridiculous statement from people, and I don't understand how people think a future hydrogen economy would be any different. If and when we move to a hydrogen based energy economy, who do you think will be the ones extracting, storing, shipping, and selling the hydrogen? I'll give you one guess... the current players that dominate the petroleum/coal based energy economy. They're the ones that have the capital to make it happen.
Incidentally, the energy industry would LOVE to be able to natively produce hydrogen, and be paid for creation, distribution, and sale; they would drop oil in a heartbeat if they could, because there would be more profit at a lower cost, and that is always a win. There is VASTLY more uncertainty in doing business in the parts of the world that have the most oil than it is to do business in the first world, and that drives up costs tremendously. There are huge expenses in extraction, transportation, storage, refinement, bribes, legal issues, and taxation that just would not be encountered if they could do all of these things at home. And let's not forget that they would score a big PR win for their support of the "environment" (no more "pollution", no more spills, no more ground water contamination, etc...). There is no upside to "protecting" oil once the technology is there to produce/store/transport hydrogen cheaply.
there are always energy costs to creating portable forms of energy, but that's the issue, not that it's more energy-expensive to create hydrogen than to use it.
No, that really isn't the point. The point the previous poster was trying to make is that the energy cost of extracting, processing, shipping, and selling petroleum based products is substantially LOWER than the amount of energy extracted from the oil. This is because the energy has already been stored for us, for free, in the oil; burning the oil releases the stored energy, and digging it up costs almost nothing energy-wise. For hydrogen, however, there is no such "free store" we can dig up. Combine hydrogen with oxygen to get water, and you get a relatively huge release of energy, but we have no previously STORED source of hydrogen; we have to disassemble water to get that hydrogen. But, the energy cost of cracking water is substantially HIGHER than the amount of energy that can later be extracted from the stored hydrogen. So, there is currently no feasible way to phase out our use of petroleum; in fact, if we switched to hydrogen power in our cars today, it would drive UP the demand for oil, not decrease it (a similar problem would occur if we all went out and switched to electric cars today). The real benefit of oil is not its portability; the real benefit is that it stores vastly more chemical energy than it takes to extract it from the ground.
The main problem of all renewable energy schemes is that fossil fuels are formed by millions of years of solar energy accumulated by the biosphere and millions of years of geological pressure. It isn't that these fuels are more fundamentally efficient - in fact, they are relatively innefficient from many perspectives. It is that nature has done all the work for us - leaving us to liberate the value at our leisure. Convenient, and in the extremely narrow and short-sighted view we've taken of energy, cheap.
The problems, of course, are that we are stuck with relatively dirty fuels like coal and oil, and that these fuels are not renewable in the short term. Hence, any renewable fuel will face us with a cost-benefits problem: it will cost more to produce than an equivalent unit of coal or oil. Until we start measuring the environmental, political and future stability/planning impacts as part of the cost of burning fossil fuels, it will always seem economically preferable to stick with our old standbys.
The real issue of hydrogen or any alternative fuels (biomass derived, ethanol, etc.) is to find the most efficient way to use a renewable or sustainable energy source. Hydrogen has the convenience and benefit of being a fuel: useful from points of view of storage and self-containment.
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