New method to produce abundant hydrogen from Virginia Tech scientists.
April 5, 2013 10:45 AM   Subscribe

Does it at low temp (122 deg F) and atmospheric pressue. Uses a normal plant sugar, Xylose, and any quantity of biomass. The trick seems to be a cocktail of enzymes from microorganisms that grow at extreme temperatures such at the boiling point of water.
posted by aleph (41 comments total) 11 users marked this as a favorite
 
Those poor scientists' families.
posted by 2bucksplus at 10:46 AM on April 5, 2013 [34 favorites]


No really does it.
posted by Big_B at 10:46 AM on April 5, 2013


Well, hopefully they never have to source any of their enzymes from NEB. Twenty year old tidal generators would be more cost efficient at those prices.
posted by Slackermagee at 10:50 AM on April 5, 2013


Okay, this bit sounds very suspicious:

Even more appealing, this reaction occurs at low temperatures, generating hydrogen energy that is greater than the chemical energy stored in xylose and the polyphosphate.

That sounds like a perpetual motion claim. Now, to some degree, this sort of thing SHOULD be self-perpetuating, because it's being driven by the sun. That's the original energy input for most of the these chemicals.

But when they're claiming that they can dump X chemical energy into a tank, and get X+1 hydrogen energy out, then I definitely start thinking about scams.
posted by Malor at 10:52 AM on April 5, 2013 [1 favorite]


This results in an energy efficiency of more than 100 percent — a net energy gain

Science!!!
posted by spacewrench at 10:54 AM on April 5, 2013 [3 favorites]


Even more appealing, this reaction occurs at low temperatures, generating hydrogen energy that is greater than the chemical energy stored in xylose and the polyphosphate. This results in an energy efficiency of more than 100 percent — a net energy gain.

wat
posted by en forme de poire at 10:55 AM on April 5, 2013 [1 favorite]


PREVIEWWWWW
posted by en forme de poire at 10:55 AM on April 5, 2013


Do we really have enough Virginia Tech scientists to go around?
posted by stevis23 at 10:56 AM on April 5, 2013 [3 favorites]


Well, the journal's impact factor is > 12, so I guess it's not yet another Dove Journals scam.
posted by docgonzo at 10:57 AM on April 5, 2013


since we're talking about biological processes, it's not really perpetual motion. though i can imagine some nicely scary thriller scenarios, with runaway biological hydrogen production.... [/evil laugh]

But seriously, you have to remember that the tank is not an isolate. It's in contact with the atmosphere, and may receive energy passively in other ways. So it's not as crazy as it sounds.
posted by lodurr at 10:57 AM on April 5, 2013 [2 favorites]


OK, this is just sloppy reporting and not a claim the authors actually made. From the actual damn paper:
The maximum rate of H2 generation was 2.23 mmol H2 L−1 h−1 at 3.5 hours, and the overall H2 yield was 90 % after the first 20 h (Figure 2)
Which is great! I mean sure, not >100%, but on the flip side, actually thermodynamically possible.
posted by en forme de poire at 10:57 AM on April 5, 2013 [24 favorites]


Derrr, I'm no scientist, but wouldn't that greater amount of energy just be due to the fact that the burning of the chemical energy is less efficient than the burning of the liberated hydrogen?

Or am I completely misunderstanding that?
posted by overeducated_alligator at 10:58 AM on April 5, 2013


By "an inexpensive, plentiful green hydrogen source," I assume they mean grass, or straw. Something you don't have to fertilize or keep weed free.
posted by Kevin Street at 10:59 AM on April 5, 2013


Kudzu?
posted by aleph at 11:00 AM on April 5, 2013 [5 favorites]


Love the headline. Coulda been worse, coulda been abundant methane from VA Tech scientists.
posted by brianstorms at 11:00 AM on April 5, 2013


Pretty much, overeducated_alligator. I think they're just saying that the energy you get from the hydrogen is greater than the amount of energy it took to get the hydrogen out of the plants. As malor said, that extra energy ultimately came from the sun.
posted by Kevin Street at 11:03 AM on April 5, 2013 [2 favorites]


Yeah it didn't sound to me like impossible perpetual-motion type stuff, any more than the positive ROI of digging oil out of the ground.
posted by overeducated_alligator at 11:06 AM on April 5, 2013 [1 favorite]


It's an in vitro process, not an in vivo process - they have to purify the enzymes involved. But they have their own strains expressing His-tagged versions, so this doesn't require spending a kajillion dollars at NEB - you just need to lyse the cells and run them through a nickel column.

Using an in vitro approach has advantages and disadvantages. On the plus side, you can make a synthetic enzymatic pathway that would really mess up a cell if you tried to express it in vivo (or that wouldn't work because other pathways are diverting flux away from your desired products), but on the minus side the prep work is much more labor intensive and expensive than just growing up a vat of mutant yeast and getting hydrogen out. Still, a very cool result.

The input energy source for this is xylose, a 5-carbon sugar which is a major component of hemicellulose, which in turn is pretty ubiquitous in plants. My impression is that there's a lot of interest in making biofuels from xylose because it's common and can be liberated from hemicellulose pretty easily. But it's proven to be hard to get microbes to make xylose into a more useful fuel, like alcohol, at least at a high enough rate - so historically it's had more limited significance.
posted by en forme de poire at 11:12 AM on April 5, 2013 [4 favorites]


Malor: "But when they're claiming that they can dump X chemical energy into a tank, and get X+1 hydrogen energy out, then I definitely start thinking about scams."

They're dumping chemical energy and heat into the tank. The "+1" is some of that heat being absorbed into the reaction.

The key thing to note here is that the amount of heat required appears to be fairly modest, hinting that the process is indeed very efficient.
posted by schmod at 11:13 AM on April 5, 2013 [2 favorites]


I'm not really convinced that hydrogen "fuel" is a great way to store energy though. It's got a lot of energy per mass, but it's really hard to get that mass into a reasonably small enough space to be useful. Plus it's hard to keep it from leaking through anything you put it in.

OTOH, batteries are also only 80-90% efficient, plus they're large, heavy, expensive, slow to charge, and temperature sensitive. And what other options do we have? Flywheels? So maybe despite all the engineering difficulties hydrogen is the right answer? I think it'll hard to tell for sure until we've gone pretty far down that route.
posted by aubilenon at 11:16 AM on April 5, 2013




For storage and transport, aubilenon, I think it's probably better to make your hydrogen into light hydrocarbons (methane, say), especially if you can use non-fossil carbon for it. Much denser and less leaky.
posted by hattifattener at 11:25 AM on April 5, 2013


seemoreglass: Oh, it didn't occur to me that this could be small and light enough to do inside the car. THAT is an interesting prospect. Sugar weighs about 3x as much as the same amount of energy worth of gasoline, which is not ideal, but still seems like it could be viable.
posted by aubilenon at 11:27 AM on April 5, 2013 [2 favorites]


aubilenon: "seemoreglass: Oh, it didn't occur to me that this could be small and light enough to do inside the car. THAT is an interesting prospect. Sugar weighs about 3x as much as the same amount of energy worth of gasoline, which is not ideal, but still seems like it could be viable."

It looks like this requires some fairly precise temperature ranges*. The gas tank will need to always be kept at a specific temperature, otherwise proteins might misfold or degrade. There are also worries of proteases, which could chop up all the enzymes responsible for liberating the hydrogen.

This is completely virgin territory. There's a lot of work to be done in making these processes robust and dependable in a laboratory environment before we can even start thinking about taking them into the real world.

Thoughts: Chaperones to keep proteins folded efficiently, and maybe multiple arrays of enzymes which have different temperature affinities for use in broader ranges of temperatures.

*at least for any degree of efficiency
posted by Strass at 11:36 AM on April 5, 2013 [2 favorites]


I wanted to come make a Peak VT Scientist joke but we seem to have hit Peak VT Scientist Joke already.
posted by phearlez at 11:40 AM on April 5, 2013 [1 favorite]


I am suspecting this is not where Dreidl meant to leave that comment. I have been out-joked by an accident. This day sucks.
posted by phearlez at 11:41 AM on April 5, 2013 [2 favorites]


hattifattener: "For storage and transport, aubilenon, I think it's probably better to make your hydrogen into light hydrocarbons (methane, say), especially if you can use non-fossil carbon for it. Much denser and less leaky"

You don't want every car in the world carting around a tank full of methane. The stuff is a terrible greenhouse gas. Even if we assume that only a little bit of the stuff leaks out, it still adds up to "way too much."
posted by schmod at 11:46 AM on April 5, 2013 [1 favorite]


Love the headline. Coulda been worse, coulda been abundant methane from VA Tech scientists.

Dang, my taco futures are worthless now.
posted by tommasz at 11:49 AM on April 5, 2013


Interesting. In another development, cheaper green energy storage.
posted by never used baby shoes at 11:59 AM on April 5, 2013 [2 favorites]


Malor, that number is energy in versus energy out for the process. This explicitly does not consider the energy potential, just the input cost against the output, and then only for the process, not for the entire fuel lifecycle. How much energy is needed to grow and harvest the plan is not included either, for example.

Still, better than 100% is really promising, because this isn't just a deadweight loss. In contrast, thermal depolymerization is only 85% efficient (output/input). TD has a deadweight loss of ~15% which means that it's really only a way for not losing as badly on energy costs of waste processing rather than as a candidate for energy production.

Enzymatic processes are tricky however, and I suspect that their 3-year timeframe is, charitably, optimistic. Similar numbers were cast about by the celulosic ethanol folks, and we're still waiting a decade later.
posted by bonehead at 12:13 PM on April 5, 2013 [2 favorites]


Yeah, that's great kids.

How about now getting to work on a method for producing abundant Helium.
 
posted by Herodios at 12:18 PM on April 5, 2013


... "sugar cars" would fuel up at "sugar stations" ...

Could pranksters then sabotage those cars by pouring a bit of gasoline into the tank?
posted by Greg_Ace at 12:24 PM on April 5, 2013 [4 favorites]


Herodios: Yeah, that's great kids.

How about now getting to work on a method for producing abundant Helium.
 
Well, since helium isn't abundant on Earth in the first place, that entails significant space travel. How about we stick to what's achievable in the next few decades, first?
posted by IAmBroom at 12:26 PM on April 5, 2013 [1 favorite]


a method for producing abundant Helium.

At last estimate that's only 10-20 years away (the same as the past 50 years).
posted by bonehead at 12:29 PM on April 5, 2013


… I could be helpful in rounding up others to toil in their underground sugar caves.
posted by gubo at 12:39 PM on April 5, 2013


How about now getting to work on a method for producing abundant Helium.

I believe a sustained worldwide program involving surface detonation of nuclear fusion devices would do the trick. And the neutrons are free!
posted by echo target at 1:18 PM on April 5, 2013 [2 favorites]


How long before politicians decry this foreign Xylose and how we should be making it with American corn, if we could just give them US$5B in subsidies to kick it off and loosened the regulations allowing ADM to fertilize their fields with the composted dreams of family farmers.

Surely it will be profitable in a matter of weeks if we can just give the job creators the help they need.
posted by MiltonRandKalman at 1:51 PM on April 5, 2013


… I could be helpful in rounding up others to toil in their underground sugar caves.

Surely they'd start by strip-mining the Big Rock Candy Mountain?
posted by dubold at 4:28 PM on April 5, 2013 [1 favorite]


I came into the comments to see how many it took until there was a "wow, they're producing hydrogen?" comment. Before I clicked I guessed it'd be by number four, and damn if I wasn't three off.
posted by spinn at 5:41 PM on April 5, 2013


I think all it needs is fæcal transplant with patients with pneumatosis cystoides intestinalis, and all Virginia Tech scientists could be producing hydrogen. Methane is far healthier though.
posted by ambrosen at 2:47 AM on April 6, 2013


Wouldn't a car that made energy out of sugar have to do something with the waste product? We'd have invented cars that have to poop.
posted by empath at 10:55 AM on April 6, 2013


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