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Power Science

New Solar Cell Harvests Hydrogen From Water 222

Engadgets is reporting that researchers at Penn State have built a new kind of solar cell that can harvest hydrogen directly from water. "The folks at Penn State have now developed a process that more closely mimics the photosynthesis process in plants, and while we won't pretend to understand all the nitty gritty of dye usage and other such nonsense, we do know that such a system could eventually attain 15% or so efficiency, providing a nice and clean way to gather power for that fuel cell car of the future."
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New Solar Cell Harvests Hydrogen From Water

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  • TFA is worthless. (Score:5, Informative)

    by SatanicPuppy ( 611928 ) * <Satanicpuppy@gmCHEETAHail.com minus cat> on Monday February 18, 2008 @01:29PM (#22464918) Journal
    The summary = the article.

    The original article [sciencedaily.com] was on Science Daily [sciencedaily.com] a few days back.
    • Re:TFA is worthless. (Score:5, Informative)

      by SocraTease ( 1230292 ) on Monday February 18, 2008 @01:44PM (#22465120)
      Additionally, here's a more informative article posted by Penn State. http://live.psu.edu/story/28853 [psu.edu]
    • Don't worry; you're the only one here who even looked at TFA
  • 15% efficiency (Score:2, Interesting)

    by paulej72 ( 1177113 )
    I thought that current solar cells have efficiencies of up to 40%. So how is this better?
    • Re:15% efficiency (Score:5, Insightful)

      by PrescriptionWarning ( 932687 ) on Monday February 18, 2008 @01:36PM (#22465018)
      i think thats 40% towards creating electricity, this is 15% towards creating pure Hydrogen
      • Re:15% efficiency (Score:5, Informative)

        by SatanicPuppy ( 611928 ) * <Satanicpuppy@gmCHEETAHail.com minus cat> on Monday February 18, 2008 @01:48PM (#22465160) Journal
        Yep. And 40% is a bad number; the cells that have that efficiency rating are a long way from production. 15% is pretty similar to what most solar cells on the market get today.
      • by misleb ( 129952 )
        Electricity is, by far, more valuable than hydrogen (or any common chemical fuel for that matter). I'd take a 40% efficient solar cell that produces electricity over a 15% efficient solar cell that produces hydrogen any day.

        Also note that that the article states that they could *theoretically* get this hydrogen cell up to 15% efficient. Hard to get excited when the theoretical max of a new idea can't even match the practical (if uneconomical) maximum of existing technology.

        -matthew
        • Re:15% efficiency (Score:5, Insightful)

          by TheRaven64 ( 641858 ) on Monday February 18, 2008 @02:36PM (#22465754) Journal
          I disagree. Lots of the best places for solar collection are a long way away from human habitation. If you can efficiently produce hydrogen (or, better, an energy-dense hydrocarbon) in these places then you can easily transport it to where it is needed.

          • mod up (Score:2, Troll)

            Parent is first one to point out storage benefit... someone with points should mod up.

            This is the biggest problem with solar/wind power, the power generated often needs to be supplemented with conventional generation technologies to ensure constant energy supply. Production of stored energy source like hydrogen solves this issue.
            • Re: (Score:3, Insightful)

              by Anonymous Coward

              Parent is first one to point out storage benefit...
              Grandparent missed to point out that good storage doesn't only mean to transport energy in space, but also in time -- for later use. So, pure electrons really don't cut it ...
          • Re: (Score:3, Interesting)

            by aardvarkjoe ( 156801 )

            According to http://en.wikipedia.org/wiki/Electrolysis#Electrolysis_of_water [wikipedia.org], electrolysis of water to produce hydrogen has an efficiency of more than fifty percent, at least theoretically. If that's true, then you might be better off using the 40% efficient cell to generate hydrogen at 20% efficiency, rather than using this new cell to generate hydrogen directly at 15% efficiency.

            Of course, there are lots of other factors which might make using the new one more attractive. In particular, it certainly s

          • by misleb ( 129952 )

            I disagree. Lots of the best places for solar collection are a long way away from human habitation. If you can efficiently produce hydrogen (or, better, an energy-dense hydrocarbon) in these places then you can easily transport it to where it is needed.

            Perhaps if you didn't have some other source of chemical fuel, absolutely had to have it, and already had enough electricity. But other than that I wouldn't waste the electricity making potential. You'd be a fool to do so. You can do a lot more with electri

          • If you can efficiently produce hydrogen (or, better, an energy-dense hydrocarbon) in these places then you can easily transport it to where it is needed.

            Transporting electricity is more efficient. We lose only about 5% due to transmission in this country (total) and it could be reduced even further.

            • by Hucko ( 998827 )
              As a previous poster pointed out, the transportation through time is important too. And it is currently really inefficient. You always most of your electricity in the electric arcs that come off the machine.
        • Re: (Score:2, Insightful)

          by tixxit ( 1107127 )
          Electricity is definitely more important, but the question is, how do you store that electricity? Batteries are expensive, heavy, and wear out pretty quickly with a lot of use. Hydrogen can easily be stored in a tank, then converted (quickly) to electricity with hydrogen fuel cells. This is why hydrogen is seen as the saviour of electric cars; they make them practical. The only problem is getting hydrogen. This technology promises a way we could create hydrogen, perhaps at our house, that could then be used
    • Re: (Score:3, Informative)

      I thought that current solar cells have efficiencies of up to 40%. So how is this better?

      It allows energy storage (in the form of hydrogen) for later use. Maybe it's not as efficient as using compressed air [sciam.com], as was described in the cover story in January's issue of Scientific American, but it's still worth investigating.
    • This one isn't even 15% efficiency...That's what they think they could get up to. That's competitive with most commonly produced cells...the 40% ones you're talking about are far too expensive to be produced outside of a lab environment, so while they're more efficient, it's more practical to just put down more of the cheap ones.

      The thing that's cool about this is the conversion efficiency; converting water to hydrogen and oxygen using traditional methods isn't itself all that efficient. If they could get t
    • Re: (Score:2, Interesting)

      by cyfer2000 ( 548592 )
      Solar cells with 40% efficiency are for aerospace applications and prohibitive pricey. BTW, the grass in your backyard has an efficiency about 1%.
    • Except where space/weight might be very limited (eg. space applications), the important measure is $/W. Silicon PV is nowhere near a viable $/W for general purpose application.

      Who cares if the efficiency is 10% and you have to cover your whole house in the stuff?

    • by misleb ( 129952 )
      These product magic hydrogen. Hydrogen from plain ol' electrolysis is not magic. It is well understood.

    • It's better if you want to create hydrogen, because using electricity to convert water to hydrogen is horribly inefficient.

      However, the whole idea is pretty stupid when you consider that with today's technology you could just generate electricity, charge a battery, and run an electric car. The whole process would be much more efficient than the 15% advertised by this system, and even the 15% is just a theoretical number. Sadly, hydrogen cars are basically a scam brought about by oil companies to distract
      • Sadly, hydrogen cars are basically a scam brought about by oil companies to distract attention and funding away from gasoline alternatives that are actually realistic.

        Don't forget about BMW's $1 billion dollar participation in this scam ... what do they know about making cars anyway, eh?
      • Sadly, hydrogen cars are basically a scam brought about by oil companies to distract attention and funding away from gasoline alternatives that are actually realistic.

        I don't believe oil companies would fund with that in mind because it seems terribly counter productive.

        If an oil company were to fund an alternate non-fossil fuel, don't you think they would want to back the one that already matches their existing infrastructure? If hydrogen became the next big thing, they'd have an awful lot of new equ

        • Yes, they may have to update their existing infrastructure... but if all you had to do was go home and plug in your car, doesn't that make everything they've built so far totally useless, and leave them with absolutely nothing to do?
        • I don't believe oil companies would fund with that in mind because it seems terribly counter productive.

          The answer is painfully obvious. If the oil companies control the hydrogen production, distribution, and fueling infrastructure, then they can get rich by buying energy, making hydrogen, and selling it at a markup - which people will pay, because their car will run on it, and they will need it, and they can't make it themselves cheaper (because you have to compress the hell out of it and that equipment is expensive.)

          Remember, oil companies aren't in the oil business - they're in the energy business. It's just that currently the easiest way to get energy to the customer is through oil. They'd happily switch to anything else just so long as it made them a buck.

          That's the point exactly. There currently exist feasible alternatives to gasoline which

  • First they want to make energy from our food. Now they are making it out of our drink. What's next... Soylent Oil?
    • Soylent hydrogen is...water!
    • Re: (Score:3, Interesting)

      by Smidge204 ( 605297 )
      Thermal Depolymerization can convert almost any organic substance into raw hydrocarbons. So yeah, converting humans into oil is entirely possible.

      That's actually how I'd prefer my body to be disposed of when the med students are done with it. Burying corpses is so wasteful in the grand scheme of things.
      =Smidge=
      • no, bury your corpse, you'll still get your wish, give or take hundreds of millions of years

        the cockroaches that inherit the earth will burn you in their Cadillac Roachmobile LeSabres

    • Re: (Score:3, Funny)

      by magarity ( 164372 )
      First they want to make energy from our food. Now they are making it out of our drink
       
      I'm reminded of a mediocre Niven/Pournelle novel where dramatic climate change was blamed on inhabitants of a space station needing to be resupplied with oxygen from time to time. What will burning all the water do to the planet? Won't someone please think of the fishes??
  • photosynthesis (Score:5, Interesting)

    by wizardforce ( 1005805 ) on Monday February 18, 2008 @01:44PM (#22465118) Journal

    The water splitting requires 1.23 volts, and the current experimental configuration cannot quite achieve that level so the researchers add about 0.3 volts from an outside source. Their current system achieves an efficiency of about 0.3 percent.
    perhaps they should take a lesson from real photosynthesis and use an equivalent of a second photosystem. in photosynthesis,photosystem II is excited to a higher state followed by an electron transport system producing ATP then with a second photon to excite photosystem I which produces the reducing equivalent required for further reactions.
    • That's far easier said than done! It's just not easy to couple two excited systems in a stable way at the molecular scale.

      Even in plants, which have had millions of years to evolve this, those systems last about 30 minutes before they're destroyed.

      Far, far easier and more robust to use a conducting element to separate your two excited systems. Think of the battery as a remote photosystem II, it could easily be replaced with a photovoltaic cell.
  • by frovingslosh ( 582462 ) on Monday February 18, 2008 @01:45PM (#22465132)
    Isn't "could eventually" one of those warning phrases that tells you something is dubious, like "up to twice as long" or "she has a great personality" or "you're violating our patents but we don't want to tell you which ones"?
    • Re: (Score:3, Insightful)

      by SuperBanana ( 662181 )

      Isn't "could eventually" one of those warning phrases that tells you something is dubious, like "up to twice as long" or "she has a great personality" or "you're violating our patents but we don't want to tell you which ones"?

      Or "we'll develop it and then an 'energy company' which is a front for an oil conglomerate will swoop in and buy up all the intellectual property and sit on it."


    • Isn't "could eventually" one of those warning phrases that tells you something is dubious,

      Sure. It think it's really more like communicating an upper limit. The more interesting number would be cost/watt.
  • Worse than electrolysis of hydrogen by electricity from a nuclear power plant. (25-45%)

    And then begins the energy intensive liquification stage. Having those carbon atoms attached to your hydrogen is just a huge advantage.
    • Re: (Score:3, Interesting)

      there's nothing saying we couldn't use energy from nuclear plants to electrolyze water but considering the sheer amount of energy in the form of sunlight that is available, ignoring it is not an option. as you said, storing hydrogen is the problem although we have catalysts to react carbon dioxide and hydrogen to form numerous compounds, hydrocarbons, misc carbohydrates, even plastics. imagine it, using sunlight or nuclear power to reduce and remove carbon dioxide from the air while simultaneously making
  • by zubernerd ( 518077 ) * on Monday February 18, 2008 @01:53PM (#22465226)
    15% efficiency would actually be pretty good considering by some calculations photosynthesis efficiency is around 5 to 20%.
    Here is one calculation showing ~6.6% photosynthesis efficiency
    It takes into account things like canopy shading, which wouldn't necessarily apply to this, but here's the link:
    http://www.upei.ca/~physics/p261/Content/Sources_Conversion/Photo-_synthesis/photo-_synthesis.htm [www.upei.ca]

    I tried to find a peer reviewed one, but can't find one right now(I'm at work, break almost over... :( )
  • What they know (Score:4, Insightful)

    by jgoemat ( 565882 ) on Monday February 18, 2008 @02:36PM (#22465756)

    [...] while we won't pretend to understand all the nitty gritty of dye usage and other such nonsense, we do know that such a system could eventually attain 15% or so efficiency, providing a nice and clean way to gather power for that fuel cell car of the future.

    So they don't even pretend to understand how it works, but they know it can eventually attain 15% or so efficiency.

  • by Sandbags ( 964742 ) on Monday February 18, 2008 @02:52PM (#22465964) Journal
    Well, personally I don't care how we get H2. It's all pointless anyways. H2 will never be a common fuel for motor vehicles.

    Here's why:
    In regards to using liquid H2 in vehicles:
    - It's too dangerous. You're driving a bomb. Every car using liquid H2 is a has-mat vehicle by legal definition. Imagine the terrorists glee where they don't have to rent a car and then build a bomb because the rental car IS a bomb.
    - it must be trucked in liquid form - can't be pipelined, and therefore we'll have to deal with massive supply issues, thouands more has-mat trucks on the roads, and reduculous logistics.
    - fuleing requires extensive safety measures and extremely specialized and expensive equipment
    - you either have MASSIVE pressurized tanks (taking a very large portion of your vehicle space and weight) or you have to have the H2 actively cooled to extremely cold termurateres, requiring the car to be powered 100% of the time.

    For metal infused H2 gas vehicles:
    - well, it's much safer... but:
    - maximum range uning even theoretical technologies is about 220 miles per fill up, assuming you leave enough seating room in a large SUV for 5 people and no luggage.
    - the tank is huge, and weighs hundreds of pounds, eating at vehicle efficiency and space (too big for those small commuter cars in Europe)
    - IT TAKES UP TO 8 HOURS TO FILL UP, and requires active cooling to prevent explosions while doing it.

    H2 in general:
    - it's dangerous to use a vapor gas as a fuel. Imagine auto shops all over the country having to worry about gas being spilled during repairs? Spill hydrocarbon, just avoid dropping a spark in the liquid until you soak it up with sawdust. Cause an H2 leak and you have to evacuate the building, no different than a natural gas or propane leak. Also, if liquid H2 leaks, you not only have to worry about combustion, but vapor expansion and extreme freeze issues.
    - It costs 3-5 times more energy to make it that it would to simply run the car on electricity
    - It's expensive. best estimates, you go the same distance on H2 for 2-4 times the cost of gasoline, and that's with all the current government funding lowering the costs.
    - Where do you plan to store all the H2? Large scale containers are very difficult to make assuming you're storing it in liuquid form. We simply don't have enough room to store it in gaseous form.
    - Fuel cells don't get repaired, they get replaced. The repair costs will be immense, collision insurance even worse (not to mention the danger issues insuring rolling bombs).
    - burning H2 directly in ICEs is barely more efficient than burning ethanol.
    - minimum car price. You can forget about those $7,000 cars. Minimum price for a fuel cell vehicle will be in the 20K range once the government subsidies stop becoming affodable.

    no, we can't power every vehicle on earth on ethanol
    yes, we will run out of oil, sooner than you like to admit
    yes, we havre to do something, but what?

    What is the answer? Super conducting electrical grids (which we can make today with existing technology at reasonable costs), fed by renewable energy in target locations around the world (wind farms where it's windy, water where there's natural falls, solar in the deserts, etc). We use all that to recharge plug-in cars using batteries from Toshiba and others companies that have already been developed which have as quick as 90 second recharge times. For those of you who say we can't do it, that we can't run recharge units all around towns for people to plug into on the run, well look at how Alaska has done it, and many other countries in the fridgid north of Europe, where cars that don't have engines running need to be plugged so their heaters can prevent fuel lines from freezing. Every parking meeter in some coutries have power cables attached. We CAN do it. It's been done before. We'll still use ethanol as a backup to the battery using ethanol in ICEs until small turbines (like BMW uses in their motercycle) become more cost effective through mass production.
    • by Reziac ( 43301 ) *
      But if I grok it correctly, what this new method potentially means (and hopefully it won't be, uh, vaporware) is effectively on-demand H2 production. You store it as water, but use the H2 as you go, so there's never very much in storage, and vastly less risk. (Probably more on a par with those quart-sized propane tanks.)

      • Re: (Score:3, Informative)

        by Sandbags ( 964742 )
        well, it's only H2 on demand if you can drive under direct full sun with enough solar panels on your roof to do it. Since solar panels get 40% or so efficeinecy, and this gets 15%, and considdering solar powered cars barely run at 25MPH in desert tests after using rediculous aerodynamic and wieght reduction methods, there's no way you can make enough H2 on the run. The only possibility for this would be refueling stations making H2 on location, instead of having it trucked in, but even with that, in most
        • by Reziac ( 43301 ) *
          May not be efficient enough now, but never hurts to keep trying to make it efficient enough for Real Life. Combine several inefficient processes, and maybe you get enough volume to be useful. (Admittedly I don't know how much H2 it takes to run a vehicle, tho I'd expect it'd be similar to propane -- ie. not really much different from gasoline.)

          However, I do think you're right that it's presently more a distraction than a reality. We get a lot of "promote or enforce use of alternative energy" legislation pro
      • No you are wrong. Theres no way to produce enough hydrogen "on the go" with a 15% efficiency. You would be better off with a standard photo voltaic cell and an electric motor.
        • by Reziac ( 43301 ) *
          'Nkay... likely you are right, at least for cars.

          However, it just occurred to me that this could be useful for home heating -- and possibly replace propane for those of us who can't get natural gas, and even a fairly pricey initial setup could pay for itself in a hurry, given that water is cheap and propane costs a fortune (at its present price of $3.20/gallon, about $10/hour to keep your house at a frigid 62F). Wouldn't matter if it was inefficient, just make a bigger unit for home heating purposes (since
    • "Pointless" and "Never" are strong words, especially as you're ignoring the metal hydrates. There are fuel cells [wikipedia.org] that would use the hydrogen in the reversing reaction, but wouldn't attempt to transport it as a gas or liquid.
      • I did mention metal infused H2. It's completely safe to store, sure. It just requires extremely heavy tanks that have less than 1% of their mass as usable H2, not to mention they take 6-8 hours to "refuel" the hydrate after it's exhausted. The problem with this technology is infusing the matal with H2 generates a TON of heat, and this requires either extremely slow fueling, or it requires a lot of energy for active cooling of the tank while being filled. in fact, the energy required for active cooling i
        • Sodium borohydrate is over 10% hydrogen by weight, and about 6% when in a water solution (and thus more usable as a fuel for a fuel cell)

          If you transport the sodium borohydrate and not the hydrogen, you can do the conversion at a central location (at the solar or nuclear plant) and not have the refilling in the car, thus very different issues with cooling and heating cost in the conversion. Simply make the fuel a removable cartridge rather than a liquid or gas. The "tank" (or more accurately "tanks", to

    • by Ogive17 ( 691899 )
      Honda has a hydrogen fuel cell vehicle that will be produced in limited numbers.

      http://automobiles.honda.com/fcx-clarity/ [honda.com]

      There's a video of Jay Leno and the Clarity which pretty much debunks most of your reasoning about hydrogen never being viable. Honda is obsessed with safety, if they didn't think it could be done they would not continue to pour money into the R&D.

      http://www.hydrogencarsnow.com/blog2/index.php/celebrities/jay-leno-takes-honda-clarity-for-a-ride/ [hydrogencarsnow.com]
      I'm not sure if the actual vid
    • Re: (Score:3, Interesting)

      by evilviper ( 135110 )

      It's too dangerous. You're driving a bomb.

      As opposed to current gasoline vehicles, which are non-flammable.

      Imagine auto shops all over the country having to worry about gas being spilled during repairs?

      Every auto shop I've been too has very high ceilings, and big, wide open doors that can easily vent TONS of vapor.

      Cause an H2 leak and you have to evacuate the building, no different than a natural gas or propane leak.

      When my idiot neighbor put a shovel through a natural gas line, the fire department didn't t

  • Fuel cells is not what will drive demand for hydrogen. Instead CO2 neutral ways to produce ammonia, which is used to create fertilizer and a huge variety of compounds used to produce pharmaceuticals will be driving alternative means of generating hydrogen. As prices of natural gas rise producing fertilizer and drugs will get increasingly more expensive, and that will hit the poor of the world very hard unless alternative hydrogen sources are found. It is a particularly interesting application of wind power
  • Oh no! When the "singularity" of computer intelligence is reached, the machines are going to take over the world and then they will process all the water on earth into energy using solar panels. What use do machines have with all the water? Then answer is none. Maybe THAT is what happened to mars?
    • Hopefully something didn't just zing over my head... but you do realize that the waste product of hydrogen fuel cells is H2O. Hydrogen is just the storage medium. I have a strong feeling that "the singularity" of which you speak won't even try to store energy in a chemical fashion.
  • Sandia, Stirling Energy Systems set new world record for solar-to-grid conversion efficiency [sandia.gov]
    31.25 percent efficiency rate topples 1984 record

    ALBUQUERQUE, N.M. --On a perfect New Mexico winter day -- with the sky almost 10 percent brighter than usual -- Sandia National Laboratories and Stirling Energy Systems (SES) set a new solar-to-grid system conversion efficiency record by achieving a 31.25 percent net efficiency rate. The old 1984 record of 29.4 percent was toppled Jan. 31 on SES's "Serial #3" solar dish Stirling system at Sandia's National Solar Thermal Test Facility.

    Each dish unit consists of 82 mirrors formed in a dish shape to focus the light to an intense beam.

    The solar dish generates electricity by focusing the sun's rays onto a receiver, which transmits the heat energy to a Stirling engine. The engine is a sealed system filled with hydrogen. As the gas heats and cools, its pressure rises and falls. The change in pressure drives the pistons inside the engine, producing mechanical power, which in turn drives a generator and makes electricity.

According to the latest official figures, 43% of all statistics are totally worthless.

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