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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.)"
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.
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.