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Biotech Science

Microbes Churn Out Hydrogen at Record Rate 168

FiReaNGeL writes to mention that Penn State Researchers have improved on their original microbial electrolysis cell design bringing the resulting system up to better than 80 percent efficiency when considering all energy inputs and outputs. "By tweaking their design, improving conditions for the bacteria, and adding a small jolt of electricity, they increased the hydrogen yield to a new record for this type of system. 'We achieved the highest hydrogen yields ever obtained with this approach from different sources of organic matter, such as yields of 91 percent using vinegar (acetic acid) and 68 percent using cellulose,' said Logan. In certain configurations, nearly all of the hydrogen contained in the molecules of source material converted to usable hydrogen gas, an efficiency that could eventually open the door to bacterial hydrogen production on a larger scale."
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Microbes Churn Out Hydrogen at Record Rate

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  • From the PSU Press Release [psu.edu]:

    "This process produces 288 percent more energy in hydrogen than the electrical energy that is added to the process," says Logan.

    That illustrates just how big the jump in efficiency is here. These bacteria are amazing little energy multipliers. It's quite astonishing!
  • by Gregb05 ( 754217 ) <bakergo@@@gmail...com> on Tuesday November 13, 2007 @07:03PM (#21343031) Journal
    It's 0 sum with how much greenhouse gas is being captured by growing the plant.

    The only thing that ISN'T 0-sum would be pulling greenhouse gases out from hundreds of feet underground; Which we already do.
  • by Gregb05 ( 754217 ) <bakergo@@@gmail...com> on Tuesday November 13, 2007 @07:06PM (#21343057) Journal

    Guess what -- this working microbial fuel cell takes C,H,O in as vinegar or cellulose, and outputs H2 and CO2! Do you really call that 'carbon neutral' as a fuel source? It's still dumping CO2 into the atmosphere, just less of it per Joule of useful energy.
    Yes, I do call it carbon neutral. The plants take in C02, H20 and E to create vinegar and cellulose, and due to thermodynamics, plants can't create more H20 and C02 than they take in; so by definition it's carbon neutral.
  • Guess what -- this working microbial fuel cell takes C,H,O in as vinegar or cellulose, and outputs H2 and CO2! Do you really call that 'carbon neutral' as a fuel source?

    Yes, because that's what "carbon neutral" means. You only release as much carbon as you took out of the biosphere in the first place. It's not taking carbon that had been sequestered away for millions of years and releasing it over a 100 year timespan.

    Of course, it's not 100% efficient, so it's still only a fancy battery. The additional power has to come from somewhere, and hopefully it won't be oil or coal. That said, I think supercapaciters are a more promising form of fancy battery.

  • What about the CO2 (Score:2, Informative)

    by Iberian ( 533067 ) on Tuesday November 13, 2007 @07:10PM (#21343089)
    Considering the byproduct is CO2 we would have to come up with a solution to that problem as well. Granted it is better than having CO2 spewed from each tailpipe concetrated at a single powerplant and in theory contained in some way but for what use?
  • Re:Uhm (Score:5, Informative)

    by Rei ( 128717 ) on Tuesday November 13, 2007 @07:29PM (#21343321) Homepage
    Hydrogen beats the crap out of batteries as far as energy storage

    Not currently it doesn't. Top-of-the-line hydrogen-powered vehicles are about on par, range-wise, with top-of-the-line lithium-ion powered vehicles (for vehicles released this fall, say, compare a Roadster with an Equinox -- both 200 mile range). But they're notably less thermodynamically efficient and have worse performance. Honda has a prototype FCX that they say will be able to get 350 miles by using an undisclosed storage material, but storage materials always raise issues of their own (such as how much energy it takes to get the hydrogen in and out -- thus hurting the thermodynamic efficiency even more), and if you want to count vehicles that don't exist yet... Of course, if your energy source is hydrogen *to begin with*, sure, hydrogen would be a better choice present-day. We'll have to see how each respective technology advances. Personally, I'd rather we be driving largely on grid power instead of trying to store all our energy on the vehicle ;)

    Getting this sort of tech as a backyard/rooftop energy generator could be insanely useful

    You want them to eat your roof? You did read the article (or even the summary) and realize that these aren't photosynthetic bacteria, right? That will almost certainly come in the future, but that's not what we're dealing with here.

    A biological system would (probably) be lower setup than a solar system as well, at least given current tech.

    But maintenance can be very tricky. Bacteria mutate, get attacked, and so on. Plus, you need to keep feeding them and removing waste products. This is certainly viable, present-day, in industrial scale applications, but it probably won't scale down very well any time soon.

    I will agree with you on one thing:

    Wow. And 80% efficiency is pretty damn good, for a line of research that is still pretty primitive.

    It sure is.
  • by Surt ( 22457 ) on Tuesday November 13, 2007 @08:03PM (#21343723) Homepage Journal
    I believe the tradition is that carbon neutral means into the air in modern times.

    When you burn fossil fuels, you release carbon into the air that was not fixed into the fuel in modern times. So you release 'new' carbon into the air. Carbon positive.

    When you burn these fuels, you re-release carbon into the air which was fixed in the last year. This is carbon neutral (no change to atmospheric carbon over short time horizon).

    If you take some plants that have fixed some carbon and bury them under a continental fold, that's carbon negative.
  • by Planx_Constant ( 594897 ) <planx.constant@gmail.com> on Tuesday November 13, 2007 @09:10PM (#21344337) Homepage
    The 20% is lost to the environment as heat, or is unable to be extracted. That's what efficiency means. If they were achieving 100% efficiency, the headline would probably read a little differently.
  • by IndustrialComplex ( 975015 ) on Tuesday November 13, 2007 @09:51PM (#21344687)
    Even if we converted 500 million barrels of water per day into pure hydrogen and launched it into space directly it would take over 40 million years before we ran out.

    3.26x10^20 gallons of water on earth
    divided by
    (5.00x10^8 x 42) gallons used per day /365

    ~42 million.

    Not on my list of priorities to worry about.
  • by aktbar ( 22510 ) on Tuesday November 13, 2007 @09:52PM (#21344699)

    What happens if you repeat the cycle of: {snip}
    an infinite amount of times? You run out of water.

    There are a few reasons to not worry about this:

    (1) The volume of the earths oceans is enough that if we were destroying water in them at the rate at which we burn oil, it would take a few hundred million years to run out. We wouldn't be destroying it at that rate (I would guess, since you can make a lot of hydrogen from just a little water), but even if we were we have a while to figure out a solution.

    (2) Hydrogen and ozone react really well -- the hydrogen wouldn't make it out of the atmosphere before it got bound back up as water.

    The down side of (2) is that we could damage the ozone layer with leaked hydrogen (http://gcep.stanford.edu/research/factsheets/effects_climate.html [stanford.edu])
  • Re:Uhm (Score:3, Informative)

    by Fordiman ( 689627 ) <fordiman @ g m a i l . com> on Tuesday November 13, 2007 @10:16PM (#21344891) Homepage Journal
    "Hydrogen beats the crap out of batteries as far as energy storage"

    That really depends on the drivetrain involved. For example, Natural Gas ICE's, like those used in city busses, top out at 30% Carnot (pretty damned low). Our best HFC electric drivetrain will put out 35% Ideal (higher than 35% Carnot) at high load, but the number of cells needed to effect that kind of output are high (heavier 'engine'). Include the 80% efficiency from generation, and the 25% efficiency hit for making the hydrogen liquid, and you end up with an overall efficiency of around 20% Ideal (still higher than 30% Carnot at ICE temperatures - which is around 6.3% Ideal efficiency).
  • by khallow ( 566160 ) on Tuesday November 13, 2007 @10:22PM (#21344931)
    Methane from natural gas is the primary hydrogen source for fixing atmospheric nitrogen to form ammonia. And that in turn is the primary contribution of fossil fuel deposits to fertilizer.
  • by StellarFury ( 1058280 ) on Tuesday November 13, 2007 @10:50PM (#21345135)
    RTFA. This process has nothing to do with electrolysis, they're converting cellulose (loads of carbon) and glucose (C6H12O6) into hydrogen. Neither of those are water.
  • Re:Uhm (Score:3, Informative)

    by Rei ( 128717 ) on Wednesday November 14, 2007 @01:31AM (#21346343) Homepage
    Thermodynamics applies to *everything*, not just heat engines. Are you confusing thermodynamics as a whole with the Carnot limit?

    All processes are lossy. Batteries, however, are very minimally lossy. Charging and discharging a lithium-ion battery loses virtually no power. Not so with hydrogen. The best you'll do with a fuel cell is something like 70% efficiency. Likewise, excepting these special cases of direct hydrogen generation, creating the hydrogen itself is also a lossy process. And there's loss in putting it into the tank -- especially when there's a storage medium used (which sometimes also gives losses in getting it out of the tank).

    EV's on the other hand, need to sit at a charger for a minimum of a couple hours

    The Tesla and the EV series do, but this isn't an inherent limitation of EVs. For example, check out this patent [uspto.gov] from the company EEStor, a company with a market capitalization of ~$60m which is making ultracapacitors on contract for ZENN. To translate, that's 342 Wh/kg (compared to 150-200 Wh/kg for Li-ion. And it has a lower discharge rate and doesn't lose capacity like Li-ion. Which is what I was getting at with my allusion to not counting vehicles that don't yet exist for hydrogen, because if you do that, you ought to count advancing battery tech to. Ultracapacitors charge incredibly rapidly -- in the case of the aforementioned EESU, a reported 4-6 minutes. The bottlebeck is no longer your vehicle, but the wires to your house ;) They're definitely cross-country capable, especially if gas stations start creating rapid charging stations. That is, if they can actually bring them to market.

    It's a mass produced, production fuel cell vehicle with the full interior room of a normal Equinox, that'll be driven by 1000 "owners" in the 3 major cities next year

    It sounds an awful lot like the EV1 program. Which I don't think should be very encouraging to anyone. By the way, AFAIK, it's 100, not 1000.
  • by Anonymous Coward on Wednesday November 14, 2007 @02:51AM (#21346777)
  • Re:Uhm (Score:3, Informative)

    by InvalidError ( 771317 ) on Wednesday November 14, 2007 @05:42AM (#21347479)

    To translate, that's 342 Wh/kg (compared to 150-200 Wh/kg for Li-ion. And it has a lower discharge rate and doesn't lose capacity like Li-ion.

    Much of the self-discharge we see in contemporary Li-ion batteries comes from built-in monitoring circuitry made necessary thanks to classic lithium chemistry's volatility. More advanced lithium technologies like AltairNano's NanoSafe will drastically improve lithium cell's reliability, durability, safety, high-current charge/discharge capability along with a few other parameters. Unfortunately though, all these improvement come at a slight cost in energy density.

    I wonder how long it will be until they start licensing their technologies for general use - it would be really nice to have laptop/ups/phone/camera/etc. batteries with 6-10 years half-lives instead of the current 1-4. I would not mind paying $50 extra on my next Dell laptop to get a similar capacity NanoSafe battery upgrade and be practically guaranteed it will be the only battery I will ever need for it even if I keep the computer for 5-10 years.

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