Slashdot Mirror
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).
Would it be better to find new and amazing ways to create energy from resources now, or would it be better for humanity to first learn to live within our means as oil runs out?
Humans have shown over and over that in large groups we use all the resources available, don't slow or restrain ourselves in time to save ourselves, and unless there are consistent, strict rules and provisioning in place, we exhaust available resources.
I think it would be better for the long term survival of the species if we ran out of cheap, easy energy sources for several generations, and we designed new culture based on long term sustainability instead of constant growth. If discover or invent an even cheaper, easier way to get energy out of water now, we'll have another "industrial revolution" type of growth, and come to an even worse dead-end when that runs out too.
If you want to store energy at night you'd probably be better off going with solar thermal + liquid salt thermal storage + water thermochemical cracking. Hydrogen is better used as a chemical fuel or used in synthesizing other chemicals. It's very good at reducing things or powering fuel cells but as a method of storing solar energy on a daily basis, not so much.
Sigs are too short to say anything truly profound so read the above post instead.
MIT, hydrogen, green, McArthur grant winner, genetic engineering, nano something or other, all these buzz bullshit in the short summary paragraph.
Stinks of bullshit to the high heaven.
Fuck systemd. Fuck Redhat. Fuck Soylent, too. Wait, scratch the last one.
True. But there are other renewable source with intermittent output that can be used for electrolysis, like wind power. And where I live, the potential power from wind is about five times that of solar.
Also, you don't want methane. You want gasoline. By the time you end up with methane, you have gasoline.
Yeah, yeah, I know. I'd be happy with methane first, since it's already much easier to handle than plain hydrogen. Synthesizing longer chain hydrocarbons might make the fuel more convenient, but also requires more effort.
Baking soda is a carbon dioxide capture system.
The problem with CO2 is that you'll need _lots_ for the industrial process, and there's only very little of it air (300-something ppm). Extracting that is a major pain in the rear (i.e. requires lots of energy).
The energy density of hydrogen as compared to liquid hydrocarbons is pathetic. The best use of hydrogen would be to to synthesize hydrocarbons, of course at that point you'd wonder why you bothered with hydrogen at all instead of just making biodiesel from algae.
Powerplants can burn other things containing carbon than fossil coal, for example garbage and waste from food- and wood-production.
Some time in the future we might also burn a lot of biproducts from when making ethanol, biodiesel and other biofuels.
The energy density of hydrogen as compared to liquid hydrocarbons is pathetic. The best use of hydrogen would be to to synthesize hydrocarbons, of course at that point you'd wonder why you bothered with hydrogen at all instead of just making biodiesel from algae.
First time I hear of a molecular property being described as pathetic.
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
Furthermore, the crucial advantage of hydrogen is the lack of carbon atoms, its combustion (or catalyzed oxidation, as in a fuel cell) resulting only in water.
...and how much energy you have to spend to get it compressed enough so that a given volume has a similar energy density as hydrocarbon, making it a viable replacement.
Tequila: It's not just for breakfast anymore!
If we can demonstrate an 800-bar compressor that's relatively efficient, and carbon fiber composite or other tanks to store hydrogen, and somehow make room for the still-3x-bigger fuel tank [http://planetforlife.com/h2/h2swiss.html] in a subcompact car, and also reclaim the energy that's necessarily used to compress the hydrogen when we release it (because otherwise it will really be too inefficient to store compared to the alternatives), that's awesome.
In fact, if we can just get people to pay for engines using inconel or ceramics and recuperators, that would also be awesome, since we could substantially increase the efficiency of existing engines using existing materials and technology. We could burn the fuel hotter to raise the Carnot limit and reuse more waste heat. At least we're pretty close to getting them to switch to turbine-electric drive trains, which is even better. (We already do mass-produce inconel turbine blades in the form of turbochargers, so we're in good shape to mass-produce Capstone-style microturbines. They are already produced at some scale. If only recuperators didn't weigh and cost so much...)
Until then, it makes some sense to at least talk about compounding hydrogen with carbon, if we have the hydrogen. We have relatively good ways to collect the carbon from the air in a well understood, not yet industrial-scale, process [http://academiccommons.columbia.edu:8080/ac/handle/10022/AC:P:6744], to obtain carbon neutrality. (I say "relatively" because you're really climbing a hill on that one, with the low concentration of CO2 in the air. That's why plants are so inefficient, and why they respond so strongly to more CO2, and why the latest evolutionary arms race is in collecting CO2 - see C4 plants [http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/C4plants.html].)
Or, as the GP suggests, let algae do the job for us, although I think we're already near the point where we can beat the land-to-wheel (system energy efficiency per unit land used) and dollar-to-wheel ROI of algae with industrial processes (limestone cycle above for the carbon, Fischer-Tropsch-style synthesis with reverse water-gas shift on the back end, solar thermal collection for energy in). (I am personally swayed by the arable land use drawbacks of biofuels, but, it really comes down to the numbers to know what's really more land-efficient. Anyway, algae have some potential to sidestep these arguments.)
So, we actually have a pretty good idea how to run a car on sunlight via hydrocarbon fuels, it's just not as cheap as pumping oil out of the ground, so we don't. We can even run a car on sunlight via various high temperature fuel cells, if you prefer more of a closed-loop system. None of these is really that efficient, but at least we can make favorable comparisons to, e.g., the corn ethanol boondoggle. (And we can, on that basis, for example, pretty much punt the zinc cycle due to the inefficiency of that particular calcination reaction.) What we can't compare to is gaseous hydrogen, because we don't even know how to build several components in that fuel chain, so we don't know exactly how bad it will be. Sure, it looks bad, but I can't claim it's guaranteed to be worse.
So, let's do research on light, high pressure (800-bar) tanks and thermodynamically efficient 800-bar compression / decompression cycles. (And especially on thermolysis and photolysis to produce the hydrogen.) But let's not pretend it's already done, and let's also work with what we have. When oil really starts to get expensive, we have several mature possibilities already on deck, which fit well into our existing infrastructure. We also have H2 in the future, when and if those problems are solved satisfactorily. And then, I hope, direct mass-energy fuel systems, for even more density and land use / environmental benefits than we can ever get from our pathetic chemical fuels.
(I'm going to give you the benefit of the doubt and assume that you are claiming CO2-free combustion is good because it avoids