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Possible Breakthrough In Hydrogen Energy
destinyland writes "MIT researchers have developed a method of splitting a water molecule by emulating the way blue-green algae separates oxygen from hydrogen. One chemistry professor called it 'an extremely clever piece of work' that addresses 'the nanoscale organization of the components.' Using sunlight rather than electricity to make hydrogen from water could greatly improve the efficiency of the process. The hydrogen can be stored for generating electricity or burned as fuel for cars. The project is being led by the winner of a 2004 MacArthur Foundation genius grant, who uses genetically engineered viruses as templates for nanoscale electronic components. 'Suddenly, I wondered, what if we could assemble materials like the abalone does — but not be limited to one element?'" Here is the press release from MIT; the research paper is available only to subscribers of Nature Nanotechnology (or those willing to part with $18).
This is from what I've read on the subect, quite impressive in terms of how it works however, this isn't a technology that is very likely capable of exceeding the efficiency of a few other methods of producing Hydrogen. 10% solar => Hydrogen efficiency would be impressive for a biological system but well within reach of other technologies like solar thermal + water thermochemical cracking This technology might be of use if alternatives remain comparatively expensive.
Sigs are too short to say anything truly profound so read the above post instead.
The only reason viruses are hard to deal with has to do with the fact that we can't accidentally kill the host trying to "kill" the virus. Since there isn't a host worth worrying about in this design, we don't have to be nice; we can just wipe the virus out without mercy.
Sigs are too short to say anything truly profound so read the above post instead.
This story appears to be a dupe.
Iridium, a form of unobtainium, is used. This costs upwards of $13,000 per kg. About 3 tons are produced a year.
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Some genuinely incredible work has come out of the labs at MIT; however, the work described in this article is pedestrian. Frankly, Prof. Belcher is a seriously over-rated, one-trick pony. Don't get me wrong, it's a hugely impressive trick - essentially directed evolution of viruses to get their capsid (i.e., proteinaceous component) to selectively bind to [whatever], but she applies it to whatever the current hot topic is, such as the photocatalytic splitting of water, and has absolutely done it to death. It's her hammer for the world of research nails.
Some of you may recall one of her papers a few years ago on virus-based lithium ion batteries. That work was also Belcher's brainchild, used the exact same techniques as are found in this Nature Nanotech paper, and was also ridiculously over-rated.
The problem with MIT is shameless self-promotion - and it's self-perpetuating because people (even the MIT professors spouting their own greatness) believe it. Another example is Robert Langer, whose work is fine but unremarkable. However, because he's so well known and great at self-promotion, he gets papers in Science/Nature/etc. As a result, his fame continues and the accolades continue to pour in.
It's frustrating to watch, knowing that fame and accolades are often undeserved when brilliant work from lesser known researchers goes unnoticed, but there's really no solution other than to point out when particular academics get more recognition than they deserve and hope that others reading agree and spread the word.
170 petawatts. We use 10 terrawatts. But our energy demands are fixed. Even the hated USA uses 10 kW per person. And as societies get more industrial, people have less kids (apparently, people like cars, computers, cell phones, etc. more than kids). The best way to conserve energy is to promote economic development, so we start to reduce population growth. One thing about the sun though is that if you fill the whole planet with solar panels, you do not run out of energy. You just get 170 petawatts. We can't use it up until peak solar in the year 1 billion (approx) because the sun will start to explode. When we do, I think we won't care about sunlight anymore, except to light our crew cabins :-p.
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The amount of hydrogen that escapes that way will be very small. That's wasting money, and no self-respecting capitalist pig would let that happen! But seriously, most of the hydrogen would be reacted with CO2 to create the liquid fuels we all know and love.
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You're not getting energy "out" of water. You're getting energy out of solar radiation.
Yup, hydrogen is just a battery: you charge it by removing the oxygen, then discharge it by burning it (which recombines the oxygen atoms and reforms water).
(unless, of course, you're doing fusion, then hydrogen IS a power source)
Nonetheless, you are wrong. Wikipedia (http://en.wikipedia.org/wiki/Energy_content_of_biofuel) is kind enough to show us that the specific energy density of hydrogen (120-140 MJ/kg) is much higher than that of hydrocarbons (55 MJ/kg, Methane). The low density of hydrogen makes it less energetic only in volumetric terms
Doesn't the effective energy density of hydrogen depend on the pressure to which you can reasonably compress it, and the pressure at which you can effectively store it?
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
If it is used in the presence of pure oxygen that is correct.
If it has access to other elements then you will get some pollution,
but it beats everything we are currently using in green terms.
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That is a concern for vehicles, certainly. Not so much for buried tanks.
It is less of a concern in stationary installations, but you have to compress the gas, and since we're using methane as a comparison, it's dramatically easier to store methane simply because it's a larger molecule, and it's easier to use due to lack of problems with hydrogen embrittlement. You can convert existing gasoline engines to run on methane, though nobody does because it's not sufficiently available. Instead, they do it with propane, from which the difference is probably a re-jetting, or perhaps a change in working pressure. But converting existing engines to hydrogen would fail because the metals are not treated to resist embrittlement, and extended use would lead to engine destruction. Presumably, valves would go first, and frequently.
The simple truth is that hydrogen is not a satisfactory energy storage mechanism until we figure out how to better store it. And it's looking more and more like the storage mechanism is going to be something with a lot of surface area rather than an empty tank. That means more mass overall, further reducing the potential lead of hydrogen over batteries. Given that practical fuel cells are perpetually 5-10 years away, the total efficiency of a system using hydrogen today would be extremely poor due to the use of an internal combustion engine, and since hydrogen engines are in their infancy compared to gasoline or diesel engines, they could be expected to be highly unreliable for a time.
Or in short, it makes far more sense to make biodiesel right now than to do anything else. In the medium term, perhaps full-EVs will be the best value proposition for most people; If the Nissan LEAF takes off it could bring about real change. Maybe in twenty or thirty years we can use hydrogen.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
Recognizing overpopulation is not human hating. I would argue that suggesting that humans reproduce until disaster is inevitable is far more "human hating" than restricting reproduction.
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you were using BD and it tripled your maintenance costs? Either I call BS or you were using common rail injection systems over 16KPsi, which are specifically *not* compatible with BD above 5%.
If your injection system runs at a lower pressure then your maintenance costs should have gone down, as BD is an awesome solvent and tends to clean things out quite well. There will be a spike in maintenance on older engines as the gunk cleans out (mostly fuel filters and earlier oil changes) but once you're past the hump, cost should fall quite nicely.
That or you used rubber hoses... Viton all the way if using BD, much like if converting a gas engine to E85 or higher, exhaust and fuel delivery components have to be changed out.
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Every time I hear people say that combustion "only results in water", I am extremely frustrated. Unless you're piping pure oxygen into the combustion chamber, you're burning/combusting using air. Air is 70% (or so) nitrogen. Combustion in nitrogen results in the creation of nitrous/nitric oxides. You can't get away from this simple fact: you're still going to make pollutants. Of course this doesn't apply to fuel cells, but the fuel cells fall under the rule that rates of chemical reactions double/halve for every 10 degree C rise/fall in temperature.
Chaos maximizes locally around me.