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Power Science

Using Sun's Energy to Split Water Means Solar Power All Night 557

phorm writes "Reuters is carrying an article about a recent MIT development which may pave the way for solar-energy to be collected for use in low-input periods. According to Reuters, the discovery of the a new catalyst for separating hydrogen+oxygen from water requires only 10% of the electricity of current methods. This would allow storage-cells to function as a form of battery for other forms of energy-collection, such as solar panels. The new method is also much safer (and likely environmentally friendly) than current methods, which require the use of a dangerously caustic environment, and specialized storage containers." sanjosanjo points out coverage of the process at EE Times, which features the MIT group's press release.
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Using Sun's Energy to Split Water Means Solar Power All Night

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  • If this is true... (Score:5, Interesting)

    by quantum bit ( 225091 ) on Thursday July 31, 2008 @07:19PM (#24425519) Journal

    What are the implications for things such as water purification, desalination, etc?

    Seems like a fuel cell "battery" is just the tip of the iceberg.

  • by Martin Blank ( 154261 ) on Thursday July 31, 2008 @07:27PM (#24425615) Homepage Journal

    I was thinking the same thing. I'm imagining a partially-self-powering desalination setup that cycles through seawater (filtered for particulates), extracts the hydrogen and oxygen, combines it in a fuel cell (which power is then cycled back into the system), then stores the resulting water for later drinking or irrigation.

  • by Anonymous Coward on Thursday July 31, 2008 @07:40PM (#24425753)
    Compared to the amount of money spent on vehicle infrastructure, and the resultant externalities(obesity, noise/air pollution, etc.) the cost of bike paths is a no brainer. I think it's the vast majority "that can actually use them". If you are too weak to propel yourself around for trips less than 6 mi.(10 km) then perhaps you nature should cull you from the herd.
  • by George_Ou ( 849225 ) on Thursday July 31, 2008 @07:48PM (#24425827)
    No, we're already at 70% efficiency and the researcher is now claiming close to 100%. That's definitely not a 10-fold increase in efficiency as the first article is implying. If the system is practical to construct, then 99% efficiency is certainly very impressive.

    However, you need to bear in mind that compressing and storing hydrogen is very complex and you probably don't want that kind of a fire hazard in your home. Furthermore, the biggest problem is that it's very expensive to buy sufficient panels to generate 1000W of power and it would be more efficient to simply use that power up because you're going to need it and then some if you're trying to run air conditioning. The biggest problem with solar power is that we can't generate enough power and not the fact that we can't store it. We simply don't have any excess to store in the first place.
  • by Anonymous Coward on Thursday July 31, 2008 @07:51PM (#24425863)

    Lets say your house needs 5000 W.

    Let's not. That's more power draw than the total available service into most houses; and most houses don't exactly draw at max for 8 hours straight. Divide your numbers by 5, and you have a more reasonable estimate.

  • by Carnildo ( 712617 ) on Thursday July 31, 2008 @08:01PM (#24425949) Homepage Journal

    There is the slight question of where and how you store your hydrogen and oxygen in the meantime so, especially for small scale "localized" applications.
    Lets say your house needs 5000 W. To get through an 8 h dark period, you need 40 kWhr, or 136,000 BTU. That's roughly the energy in 2 lbs of hydrogen. To store that much hydrogen, you either need a balloon of 11 m^3 size, or you need a compressor that allows you to store the hydrogen as compressed gas

    Eleven cubic meters is no big deal -- that's a balloon a meter and a half in diameter. You'd have trouble fitting one in your car, but houses have far more room. You can stick it in a corner of your garage, or in the attic, or wherever you've got extra space.

  • There is the slight question of where and how you store your hydrogen and oxygen in the meantime so, especially for small scale "localized" applications.

    You pump water uphill during the day. Then at night, you let it fall downhill and generate electricity from that. We don't need fancy chemical tricks or storage mechanisms to make sporadic energy sources produce constant outputs.

  • by afidel ( 530433 ) on Thursday July 31, 2008 @08:49PM (#24426445)
    Why not use a metal hydride storage both at home and in the car. Then your car tops itself off during the day and the stuff generated at home is available to refill the car for the next days commute. You size your panels and home storage to be big enough to handle your average number of severely overcast days plus a buffer, and worst case you buy electricity off the grid to make hydrogen.
  • by clonan ( 64380 ) on Thursday July 31, 2008 @09:07PM (#24426651)

    Average commute is 15 miles.
    Average electric car uses 300 watt/hours per mile (after recoving energy from braking)
    Cost effective solar cells are 15%
    Surface area of a car is 1.5 square meters.
    Solar insulation is 1 kw/h for 5 hous a day (on average)

    SOOO...

    1.5 square meters * 15% * 1000 watts * 5 hours = 1125 watt/hours

    The average commute is 15 miles * 300 watts-hours = 4500 watt/hours consumed.

    Solar powered cars won't work until solar cell efficiencies are 50% or better.

  • by Ungrounded Lightning ( 62228 ) on Thursday July 31, 2008 @09:07PM (#24426653) Journal

    The solution is touted as improving storage of renewable energy from fat hours for use in lean hours. That problem is already well in hand using various battery technologies. I doubt that, even with this improvement, electrolysis-gas storage-fuel cell will beat even lead-acid batteries, let alone lithium ion (with efficiences close to 100%) or stationary vanadium redox (with properties like fuel cells but storing the energy in tanks of liquids at atmospheric pressure).

    But it may be a DANDY solution for providing hydrogen and oxygen for powering vehicles: (fuel-cell prime-mover hybrids, hydrogen internal-combustion (at a carnot-cycle penalty), etc.) or as feedstock for energetic chemical processes.

  • by nyet ( 19118 ) on Thursday July 31, 2008 @09:19PM (#24426791) Homepage

    clicky [nyet.org]

    So we don't go with this mimic-of-the-biologicalstuff
    approach, at least for hydrogen. Dan Nocera
    and Nate Lewis organized a Gordon Research Conference
    on solar fuels in 2007 that assessed all the
    inorganic, nonplatinum hydrogen catalysts around.
    Three winners came out. One is a dimolybdenum
    system that Dan DuBois at the Pacific Northwest
    National Laboratory has worked on, and one is a
    cobalt system that Vincent Artero and Marc Fontecave
    at the Université Joseph Fourier in Grenoble,
    France, developed. The third was originally developed
    at Iowa State in the 1980s by Jim Espenson
    [BS '58], was recently improved by Xile Hu when
    he was a postdoc here at Caltech, and is now
    being worked on in my lab by grad student Jillian
    Dempsey. The DuBois molecule and the Caltech
    one are both very good. They operate at very close
    to the optimum voltage to make H2. This is a critical
    feature, because if the system's voltage is more
    than the optimum, the extra energy is wasted. And
    if the voltage is insufficient, the reaction doesn't go
    at all. But Dan's molecule contains sulfur, which
    can be nasty, and ours is easier to make, so we
    think the Caltech one looks like a real winner.

  • The Patent... (Score:2, Interesting)

    by parachutepenguin ( 1154713 ) on Thursday July 31, 2008 @09:39PM (#24426981)

    Here's the link to the Patent [google.com] that describes the invention. Interestingly the patent is drawn to the process rather than the device/product/composition which would be a stronger patent (it's harder to prove someone is using your process to produce hydrogen, rather than your product to produce hydrogen). This is probably the case because the chemicals used are not unique or new but are rather being applied in a new way.

  • by phorm ( 591458 ) on Thursday July 31, 2008 @09:44PM (#24427027) Journal

    I tend not to believe MIT because of their "popularity" so much as because of their "reputation."

    The latter could be rather heavily damaged by making unsupportable claims in regards to their research.

    Not that we shouldn't wait to see this in action, but at the very least I'll be waiting eagerly to see these experiments repeated in a controlled environment.

  • Not to mention, have you seen the waste products? I wouldn't call 'em "environmentally friendly"!

    Actually the way the waste is treated now it's unsustainable. However it would be sustainable if that "waste" were composted and made into humanure [wikipedia.org]. If you garden, depending on what you grow in the garden, your plants will love you for watering them with your urine. Not straight mind you, nitrogen burn can kill them, but by mixing 10 parts water to one part urine. They would also love it if they were watered with greywater [wikipedia.org]. That's what I did for a while, my bathtub was clogged for a while before the owner sent a plumber. So I'd use the grey water from showering to water my garden. Those who have commented about the garden said it looks real good, another gardener asked how I got my tomato and tomatillo plants so big.

    Falcon

  • Re:Gimme a break (Score:5, Interesting)

    by rah1420 ( 234198 ) <rah1420@gmail.com> on Thursday July 31, 2008 @10:06PM (#24427261)

    Show me a technology suppressed by the oil companies

    Large format NiMH batteries.

    Marketed as the Panasonic EV-95. Or rather, not marketed. You can't buy them. The only vehicles they are currently in now (no pun intended) are three hundred some-odd Toyota RAV4-EVs.

    If they are ever sold for use to power traction motors in an electric vehicle, Cobasys will slap Panasonic with an injunction to stop. And you can't buy them at any price other than in very large quantities, and the only people who can buy such large quantities are automakers. Some would say "Not a scam" but the licensing of the technology to exclude certain forms of transportation is REAL.

    Who's Cobasys? Just the joint venture between the inventor of the battery, ECD Ovonics, and -- wait for it -- Chevron.

    Here are a [investorvillage.com] few [autobloggreen.com] citations and examples. [wikipedia.org] Although things seem to be getting better, as they are being licensed in some hybrids now, and they may be expanded to more applications in the future...

  • other use for o2 (Score:3, Interesting)

    by bxwatso ( 1059160 ) on Thursday July 31, 2008 @10:22PM (#24427369)
    I don't think you have to keep the O2 to run a fuel cell; won't it run off the O2 in the air? I suspect that the O2 would be tanked and sold to hospitals and industrial uses. Also, it might be more cost effective to pipe/truck the H2 to the city to operate a fuel cell there, thereby reducing the electrical loss from long distance transmission and step-up / step-down transformers.
    Indeed, it might be best to convert all solar power to H2 and truck it to the city vs. building expensive transmission lines and pipelines.
  • by Anonymous Coward on Thursday July 31, 2008 @11:05PM (#24427715)

    240 V at 200 amps peak. Not likely,

    My bill works out to 1.4 kw average in the summer, and 5.6 kw average in the winter. All-electric house. Old all-electric house at that.

     

  • humanure (Score:3, Interesting)

    by falconwolf ( 725481 ) <falconsoaring_2000 AT yahoo DOT com> on Thursday July 31, 2008 @11:33PM (#24427945)

    However, the problem with human waste is that it can't be used for vegies because we've got a few too many nasties in it.

    Just as with urine, humanure shouldn't be used straight. Manure almost never should be. When I prepared my garden beds, I built raised beds, I mixed 1 bag of cow manure to 4 bags of top soil. Actually I got some weird looks doing that, I don't have a mixer (which breaks up the particles and clumps so it won't hold as much moisture) so I spread out on the ground a tarp, added some top soil and manure in one corner then lifted it up until they mixed in another corner. I did this 3 or 4 tymes then pored the mix into the beds and turned over that and the soil that was already there digging down about a foot. The biggest problem with humanure is all of the stuff people eliminate when they're taking antibiotics, it gives bugs, microbes, an opportunity to become antibiotic resistant.

    Falcon

  • Re:Conservation? (Score:3, Interesting)

    by TooMuchToDo ( 882796 ) on Thursday July 31, 2008 @11:45PM (#24428047)
    The crucial problem is that in economics, and the world economy as a whole, success is measured in growth. What should be measured is your environmental footprint along with your revenue to determine the sustainability of your business. Just because you can churn out a million widgets a year doesn't matter if you're tearing down the Amazon to do it.
  • by Rei ( 128717 ) on Friday August 01, 2008 @01:35AM (#24428837) Homepage

    A large fuel cell stack will cost you around $10 a watt [fuelcellstore.com] (smaller ones are more expensive per watt). Let's say that some big fuel cell manufacturer and can afford to sell them in bulk for $5 a watt. Well, go check out your breaker box. How many watts is it rated for -- 30kW? 50kW? 100kW? That's hundreds of thousands of dollars worth of fuel cells alone. Not exactly affordable. Even if you were to use a battery or capacitor buffer so that you only need to be able to provide a fraction of that, it's still priced way out of any semblance of affordability. Of course, you don't *have* to use fuel cells. You could use a H2 ICE or turbine. But then your efficiency is *even lower*.

    Batteries are really the only realistic option in the foreseeable future.

  • by FirstOne ( 193462 ) on Friday August 01, 2008 @09:08AM (#24431815) Homepage

    "For one, professors have to get grants to do their research, so they are sometimes given to overstatement to that end. They are, after all, only human which means that not all of them are honest. Also, some are simply unrealistic. They think they can do something, so they announce it, even though they have no idea how to get there, and then maybe never end up doing so. Finally sometimes shit just ends up being impossible. "

    I think this is for real, they've reduced the Voltage needed to split water down to 1.29V [sciencemag.org].. very impressive..

    This RCS article [rsc.org] (free) is somewhat more descriptive.

    They use a solution of Cobalt and Phosphate Salts.. Ph of 7. (Now that's a real breakthrough.)
    Anode is made of Indium Tin oxide (ITO) and a Cathode plated with Platinum??

    It would be interesting to see how this apparatus operates @ 10 and 20 atm.. (self pressurizing storage??) and elevated temps.(Maybe reduce the voltage needed by using a thermal energy component)..

  • by GPS Pilot ( 3683 ) on Friday August 01, 2008 @02:40PM (#24437881)
    Spin up a flywheel during the day. Compress air in a tank during the day. Charge a lead-acid battery during the day... etc

"Everything should be made as simple as possible, but not simpler." -- Albert Einstein

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