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Power Hardware Science

Artificial Leaf Could Provide Cheap Energy 326

Posted by Soulskill
from the make-like-a-tree-and-catalyze-the-electrolysis-of-water dept.
sciencehabit was one of several readers to tip news of a sunlight-harvesting artificial leaf, writing: "Nearly all the energy we use on this planet starts out as sunlight that plants use to knit chemical bonds. Now, for the first time, researchers at the Massachusetts Institute of Technology have created a potentially cheap, practical artificial leaf that does much the same thing—providing a vast source of energy that's easy to tap. The new device is a silicon wafer about the shape and size of a playing card coated on either side with two different catalysts. The silicon absorbs sunlight and passes that energy to the catalysts to split water into molecules of hydrogen and oxygen. Hydrogen is a fuel that can be either burned or used in a fuel cell to create electricity, reforming water in either case. This means that in theory, anyone with access to water can use it to create a cheap, clean, and available source of fuel."
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Artificial Leaf Could Provide Cheap Energy

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  • Vaporware (Score:5, Funny)

    by GabriellaKat (748072) on Monday March 28, 2011 @08:10PM (#35646660)
    At last, true vaporware!
  • by artor3 (1344997) on Monday March 28, 2011 @08:13PM (#35646684)

    There's only so much insolation to harvest. If this is cheaper and higher efficiency than existing solar cells, then great. Based on the article, it's only 5.5% efficient, so meh. But even if it were 100% efficient, it's not some magical free energy machine, and never can be. While it's true that "nearly all the energy we use on this planet starts out as sunlight", a lot of that energy arrived at earth several millenia ago. In the long run, we're going to need to either use less energy (preferably by making things more efficient, not making do with fewer things) and/or get some near-unlimited fuel source, like fusion.

    • by timeOday (582209) on Monday March 28, 2011 @08:30PM (#35646838)
      No, actually there is plenty of sunlight to power all current needs and more [theenergycollective.com], if we could capture it efficiently.

      Yup, I linked to a page claiming to "debunk" this "myth" on the basis it would take a solar panel the size of Georgia to power the whole earth. Big deal! Vastly more land is consumed by agriculture. Just reclaiming all the space on rooftops, roadways, and parking lots for solar would account for a lot of that, puttng power generation right where it's needed.

      And then there's there's the 2/3 of the earth covered by water nobody is making much use of. If cheap solar devices can produce hydrogen, it can be shipped long distances efficiently.

      • by Anonymous Coward on Monday March 28, 2011 @08:34PM (#35646874)

        Plus as some one who lives in Georgia I can tell you that is is hot! A solar shade for the state might work well!

        • by PopeRatzo (965947) *

          Plus as some one who lives in Georgia I can tell you that is is hot! A solar shade for the state might work well!

          If you leave Savannah alone, you can cover the entire state of Georgia with a solar panel and nothing would be missed. We never did finish that whole "Reconstruction" thing, so now might be a good time.

      • by Gerzel (240421)

        The big question I see with this is just how clean does the water going in have to be?

        Sunlight is free, but clean water is not.

        • by haruchai (17472)

          So far, they've tested using water from the Charles River, presumably unfiltered. Next they'll try using seawater. Stay tuned.

        • Re: (Score:3, Informative)

          by sunzoomspark (1960660)

          The big question I see with this is just how clean does the water going in have to be?

          The article said they'd been running it on water from the Charles River, so it doesn't have to be very clean.

      • When you start talking about that scale, even solar is no longer free. All that sun, hitting the land or the sea, you don't think that energy is otherwise "wasted" or destroyed? It goes to heat the earth. If you capture it with solar panels or other methods, that energy never gets where it was going.

        I don't have any good idea what the impact of that is, but you can't just discount it as "free".

        • Re:no free energy (Score:4, Informative)

          by Black Gold Alchemist (1747136) on Monday March 28, 2011 @09:16PM (#35647182)
          If you have solar panels capture the energy, they simply suck the energy up, store it, and when it returns as heat in the friction of the objects it moves, the lights it powers, etc. Without the solar panels, the light would just be heat. So it is free.
          • by ArcherB (796902)

            If you have solar panels capture the energy, they simply suck the energy up, store it, and when it returns as heat in the friction of the objects it moves, the lights it powers, etc. Without the solar panels, the light would just be heat. So it is free.

            OK. But what if I use it to run my air conditioner or refrigerator??

            (Yes, I know. Don't call me a dumbass or someone will "Whoosh!" you)

            • by jms (11418)

              Go feel the air blowing through the outside-part of your air conditioner or the air blowing out of your refrigerator vent in the back or on the bottom.. It's warmer than the air that went in.. That's where the heat is going. Air conditioners and refrigerators separate hot from cold, they don't generate cold only. They actually make more heat than they make cold. The difference is equal to the energy in the electricity used to run the air conditioner or refrigerator.

          • I agree.. mostly. The natural state of things would have the sunlight hit the natural objects like rocks, soil, shrubs.. whatevs. The energy being instead absorbed, transmitted, and then used elsewhere would impose *some* kind of imbalance or unnatural/irregularity. The degree to which this would matter is yet to be seen -- and the degree to which it matters as compared to using fossil fuels is NIL. So I agree mostly. Maybe in the year 2400, we have green energy out the wazoo, and we discover a new dis

        • by drinkypoo (153816)

          The problem with this notion is that there's less soil coverage today, so if anything you'd be helping to reduce man's impact.

      • There is not an energy production problem there is an energy storage problem. Almost all green sources of energy have have down times. In the case of solar energy that is night. If we could store some of the energy produced in the day we would be much further ahead. There is some research and a few test being done but energy storage is not as "sexy" as energy production.

        • by socsoc (1116769)
          Some people call that a battery.
          • by jklovanc (1603149)

            How big do you think a battery would have to be to supply electricity to New Your City for 8 hours at night? Batteries are not a viable solution for storing power on a large scale.

        • Let me describe a physical energy store.

          1) Large uphill reservoir. Water below it.
          2) Excess energy produced in realtime is used to power pumps and run water uphill into the reservoir.
          3) As realtime supply drops off and demand remains, water is released back through generators.
          --
          There would be losses in the transfer from light - electric - kinetic - potential - kinetic - electric, but it would be easy and cheap to implement, and useful in nearly all parts of the world.
          --

          Some other places are using large

          • by jklovanc (1603149)

            How many of these storage devices have been made or even planned? The technology exists but has not been implemented on a large scale. I know of very few. You also forgot about flywheels and compressed air storage.

            The raised water technology works great in the mountains but what about Kansas? Also you require space for two large reservoirs. How many valleys to we loose to energy storage? It also requires three separate sets of machinery that need to be built and maintained. All that equipment costs money an

      • 1- You can't ship hydrogen cheaply or efficiently. 2- the biosphere (fish) like having sunlight on the ocean. 3- distributed energy is too hard for rich people to profit from, they prefer centrally generated power, with metering.
        • by ArcherB (796902)

          1- You can't ship hydrogen cheaply or efficiently.

          Yes you can! You can fill giant bags with it, strap some propellers on the side and it will fly itself. Probably safe enough to include passengers who want to go along for the ride. We can call the gas ships or something similar.

          Seriously, though. Blimps had little trouble hanging on to their hydrogen as long as they were not flying infernos. I'm not recommending bringing back hydrogen blimps as a method of transportation, but they should make for a safe, unmanned self delivery mechanism. Even if they

      • Re: (Score:3, Insightful)

        by Anonymous Coward

        People keep claiming that something the size of Georgia is a sane amount of the earth's surface to cover. You know that agricultural land isn't completely covered with manufactured material, right? Even if it were, how is doubling the human footprint on the planet reasonable? That article really is a successful debunking.

        You're talking about mining enough resources to cover Georgia in something manufactured every N years, perhaps N = 30. Think about how bad that is. It's not road bed, either, it's some

      • There's still the little problem of efficient energy storage. You could outfit every home in the world with solar panels and have a huge capacity on a sunny day, but you still need power at night, storage still is an issue. As for the technology discussed here, it splits water into hydrogen, a highly flammable gas, storing this in a safe manner might also be problematic (i'm not a chemist, so i might be wrong)
    • by maxume (22995)

      That's just silly. The sun blasts the earth with petawatts of energy, we only need to harvest terawatts, the problems are all in cost, efficiency and storage, not in availability of energy.

      • by bunratty (545641)
        Quite true. A 100 mile by 100 mile solar power plant would provide all the electricity that the United States needs [americanen...ndence.com]. It would have the added benefit of never running out, as fossil fuels and fissile nuclear fuels do. Even fusion power wouldn't last long if it required deuterium, tritium, or helium instead of regular one-proton hydrogen.
        • Re: (Score:2, Troll)

          by c6gunner (950153)

          Quite true. A 100 mile by 100 mile solar power plant would provide all the electricity that the United States needs [americanen...ndence.com].

          Yes, but how many mexicans would you need to keep the panels clean? 10,000? 100,000? 100,000,000?

          Of course, the number of nuclear power plants needed to produce the same amount of electricity could fit in a 10 mile by 10 mile area. And they wouldn't need hordes of window-washers to keep operating at full capacity. Nor would they shut down at night time.

          It would have the added benefit of never running out, as fossil fuels and fissile nuclear fuels do.

          Bullshit. Everything runs out eventually.

          • by bunratty (545641) on Monday March 28, 2011 @09:32PM (#35647298)

            Well, at the point solar power runs out, we'd have to find a new planet anyway. It would provide energy for billions of years rather than hundreds. For all intents and purposes, solar, wind, and biofuels never run out.

            Also, all forms of energy generation require human workers. Who do you think digs up the coal, oil, and uranium? Who do you think runs the oil refineries, nuclear power plants, and coal plants? Do you have any evidence that we'd need more workers per unit of solar power than for other forms of power?

            • by c6gunner (950153) on Monday March 28, 2011 @10:41PM (#35647848)

              Well, at the point solar power runs out, we'd have to find a new planet anyway.

              I was more concerned about the materials which go into panel production.

              Also, all forms of energy generation require human workers. Who do you think digs up the coal, oil, and uranium?

              The same types of people who dig up the materials needed to make your panels?

              You'd need more resources (ergo, more people working) to build the damn panels in the first place, and THEN you'd need to hire tens of thousands of workers to service the panels. There's a reason why solar power is currently THE most expensive source of energy on the market, and is between 2 and 3 times more expensive over the lifespan of the panels when compared to nuclear (and 4-6 times more expensive than oil/coal).

              Do you have any evidence that we'd need more workers per unit of solar power than for other forms of power?

              You know, I had a really long comment written up, with figures showing you'd need upwards of 10,000,000 man hours to do a single cleaning, and extrapolating that to X number of full time workers and comparing it to number of workers needed to run a nuclear power plant .... but then I went and checked and it turns out solar panels don't need to be cleaned all that often. So, suffice it to say, I don't have any solid figures, and I don't think anyone else does at this point. We'd have to figure out a mean rate of failure, which would be different for different panel types, AND we'd have to figure out how often they need cleaning, which would be different for each area. You'd also have to worry about unexpected things, like tornadoes and other extreme weather (which don't generally affect nuclear power plants), and you'd have to worry about man-made problems, like Billy Bob and his cousin Cletus figuring out that there's millions of free panels sitting there for the taking. I'd say that it's fairly obvious that they would, at the very least, require a similar number of personnel as other forms of power generation, but I suspect the number would be far higher.

          • by Plekto (1018050)

            If you fast-forward even 500years in the future, there will only be a few sources of power in use:
            - Geothermal, Hydro-electric(various types), and Solar - all basically steam or water driven driven turbines. Pretty much infinitely renewable and stable technology. Note - solar cells won't be used for large-scale production, as we'll likely have run out of rare earth metals at an affordable cost by then. A few types like this article mentions also may exist for small-scale use.
            - Wind. I'm a big fan of tho

        • by rubycodez (864176) on Monday March 28, 2011 @09:45PM (#35647400)
          Actually, the deuterium in the oceans would provide fusion energy sufficient for billions of years, the sun would scorch the earth to by expansion first before we ran out. And there is lithium and boron, and we can make tritium. Fusion really is the holy grail of power generation if we can't make solar power work. http://www.engineeringchallenges.org/cms/8996/9079.aspx [engineerin...lenges.org]
          • by bunratty (545641)
            There's lots of gold in the oceans, too, but it's not economically feasible to extract it. Is it economically feasible to extract deuterium from seawater? Also, we do have working solar power today. A power plant running on fusion power may never be economically feasible or even technologically possible at all.
            • by rubycodez (864176) on Monday March 28, 2011 @10:23PM (#35647692)
              Deuterium is much more abundant than gold and far easier to extract from water (of any source, fresh or ocean doesn't matter). We've been producing and using deuterium for decades, for example as moderator in heavy water reactor. The energy cost is negligible even for fission reactor moderator, for fusion energy even smaller cost compared to yield.
        • So if you paved death valley in solar panels (with greenhouses below growing rice I expect) then you'd not need to import oil or give money to OPEC. So all America has to do is figure out how to pay the Chinese to built it.
    • by Thing 1 (178996)
      Yeah, my take is there's so much solar energy being wasted escaping into space, we really need to put a cap on it. A Matrioshka Brain, in other words. Yes, it's a large engineering feat but the politicians are too busy cozying up with the bankers for us to get off the planet...
      • > Science can explain religion; not vice versa.
        "God created man, man observed its surroundings, derived rules and models that predict changes in those surroundings and called it science."

        Science explains religion under the hypothesis that a god doesn't exist (unless evidence is given, which is a currently irrelevant clause).
        The dual is: religion explains science under the hypothesis that his god(s) exist. That's what I just did. Easy. Let's forget about God and go on.

        "Another man reasoned that if a law d

      • by ross.w (87751)
        Well, we could burn a whole bunch of coal to create extra CO2. That would form a barrier to block the escaping energy - like a big greenhouse... Oh wait...
    • ...and/or get some near-unlimited fuel source, like fusion.

      That's what solar power is -- it's just that the fusion source is millions of miles away.

      Additionally -- and I'm sure this is redundant with some other posts -- producing hydrogen directly cuts the middle man, if that's what you're ultimately going to do. I'd certainly rather putter around in one of these [wikipedia.org] or one of these [wikipedia.org] than in an electric vehicle -- and if the energy's cheap and clean...well, bring back the muscle cars, I say!

    • by Dahamma (304068)

      This isn't about solar cells or harvesting, it's about a simple and cheap mechanism for energy storage using hydrogen.

      The majority of the currently used hydrogen is still generated by fossil-fuel power, and all of the high-efficiency electrical battery storage systems use a lot of toxic (and expensive) marerials as well as having a limited lifespan.

      A mechanism that passively and directly turns water into oxygen and hydrogen, even with a fraction of the efficiency of traditional solar cells, could be very us

    • Unlimited energy won't save the world, we'd just die from the heat given off by our technology (waste heat) instead of global warming (sunlight).
      • by rubycodez (864176) on Monday March 28, 2011 @10:29PM (#35647746)
        Normal solar panels have albedo of 0.35, which is close to average of earth 0.30. We'd be far better off thermally using that than burning fossil fuel or fissioning atoms. However, comparing the energy input of the sun to what man generates, the fraction is so very tiny that the global direct thermal effects (not greenhouse gases which is another discussion) of our power generation in essentially zero.
      • by joocemann (1273720) on Monday March 28, 2011 @11:38PM (#35648334)

        You should consider:
        1) The energy harvested by solar would hit the earth anyway, and thanks to laws of thermodynamics, we can't get 'more' from it than would already arrive.
        2) The energy harvested using fossil fuels hit earth millions of years ago and was stored in chemical bonds that we break with combustion. If we otherwise did not choose to release this energy via combustion, it would stay in chemical form.

        There is a difference. There is also no excess blanket of CO2 being produced, where carbon that has been absent from the atmosphere for millions of years is now reintroduced, and as it is a heat storing gas, it aides in global warming.

        There is a difference.

      • Just use the unlimited free energy to run a global air conditioning unit. Hang a giant window unit off Antarctica.
    • by PopeRatzo (965947) *

      and/or get some near-unlimited fuel source, like fusion.

      I thought solar energy was fusion.

      Why are there some people who are so intent on limiting us to sources of energy where something either get burned or blowed up real good? I mean to the point where it seems like they'd support laws preventing anyone from using any form of energy that doesn't either involve the use of a scarce poisonous resource or involve waste materials that are deadly for millennia. I'm not saying that's artor3, but jesus, the abso

      • by ptbarnett (159784)

        I think it can be traced back to Ronald Reagan ripping off the solar powers placed on the White House by his predecessor, as if they were an abomination in the eyes of god.

        You discredited your entire posting with a bogus claim that can easily be refuted:

        White House Will Not Replace Solar Water-Heating System [nytimes.com]

        The panels of the system had been dismantled to fix the roof underneath. Dale A. Petroskey, a White House spokesman, said Friday, ''Putting them back up would be very unwise, based on cost.''

        • by PopeRatzo (965947) *

          Maybe you don't remember the Reagan presidency as clearly as I do, but he was a president who was keenly aware of the symbolic meaning in every single thing he did.

          Every single president makes small but symbolically important changes when taking over the White House. I believe there was a clear sub-text in the act of dismantling those solar panels. Remember, not long before there had been a serious disruption in the oil supply so there was a great deal of talk about "breaking America's addiction to oil".

    • by barv (1382797)

      You are wrong, there is plenty of sunlight energy to harvest...

      Sunlight provides 1 KW/M^2. The USA uses about 4 trillion KWH per annum (see CIA's world factbook), which is about 10,000 KWH per person per year, or 30 KWH/day/person. Assume 20% efficiency, and 5 hours of sunlight each day, then 30 M^2 of solar collectors needed per person. Hmm the average house is about 2-3 times that, and has 2-3 people.

      Or look at it another way, a square mile is about 250,000 square meters, and would produce 100,000 KWH

    • There's only so much insolation to harvest.

      From my understanding that's quite a bit. I don't think we're going to cover the planet in solar panels but still. As long as the energy required to make a panel/leaf/etc. is less than the energy produced over the lifetime of the panel/leaf there is a benefit. How much benefit and how it can be used may be a matter for debate but it shouldn't be dismissed out of hand.

      But even if it were 100% efficient, it's not some magical free energy machine, and never can be.

      Why? At 100% you would be getting nearly 100 watts out every square foot. A 150 square foot car port could capture 120kWh in 8 hours. A

  • by Culture20 (968837) on Monday March 28, 2011 @08:14PM (#35646702)
    Ooo, 5.5%. And it's *potentially* cheap!
    • by dunng808 (448849)

      According to Robin Williams, who as an alien should know what he is talking about, hydrogen as fuel for cars should be avoided. Remember the Hindenburg? Personally I don't car about the fuel, I just want my flying car.

      • by Barrinmw (1791848)
        I know you are joking, but isn't hydrogen in hydrogen fuel cells stored as Lithium borohydride which isn't really explosive?
      • According to Robin Williams, who as an alien should know what he is talking about, hydrogen as fuel for cars should be avoided. Remember the Hindenburg? Personally I don't car about the fuel, I just want my flying car.

        While hydrogen is flammable, there are doubts about it being the true cause of the disaster. Based on eyewitness accounts, the fire was bright red while hydrogen burns blue. There are competing theories like the paint composing of aluminum.

        • While hydrogen is flammable, there are doubts about it being the true cause of the disaster. Based on eyewitness accounts, the fire was bright red while hydrogen burns blue. There are competing theories like the paint composing of aluminum.

          Alright then, I guess it's ok to fly through the air in blimps filled with hydrogen. Sure.

          • by lawpoop (604919)
            It seems unlikely the hindenburg blew up due to hydrogen. Remember, hydrogen is very light, so if there's any rupture, the hydrogen will escape rather than hang around to explode. Sure, some will, but the vast majority will go straight into the atmosphere.

            That's why people buy the idea that the coating was what actually exploded.

            • See, here's the thing. You may very well be right. But I am not about to test that theory with my life by stepping onto a hydrogen filled blimp, thankyou.
              • The op asserting that hydrogen caused the Hidenburg disaster; it's not clear that it was. Also if the hydrolysis of the artificial leafs works out, it is possible to use fuels cells in practical applications. The main problem of fuel cells is getting and storing hydrogen fuel to power the cells. As for handling hydrogen, it probably is no more dangerous than handling natural gas. There is a difference between using hydrogen as the fuel and hydrogen as buoyancy gas.
    • by Shikaku (1129753)

      Which is utterly pointless and just a factor to increase for more energy output. Wasted energy by not being able to absorb sunlight isn't a big deal: there's sunlight everywhere on average half of the day, barring clouds; wasted energy in gasoline is bad for example because there's limited amounts and/or it's expensive. The energy output/$ is much more important, as well as the ease and resource to make it.

    • by Solandri (704621)

      Ooo, 5.5%. And it's *potentially* cheap!

      Photosynthesis in sugar cane is 7%-8% efficient [wikipedia.org] and compared to this is practically free (needs water and land, but so does this). The stuff manufactures itself for crying out loud, we don't even have to invent nanomachines to construct it for us.

      The whole point of photovoltaic panels is that they convert the sunlight directly into electricity for our applications which need electricity. If instead you're going to convert the sunlight into a hydrogen-based fuel

      • by sl149q (1537343)

        Yes, but you then have to convert the sugar cane to something else (ethanol for example). So you have to look at how much energy you get out of the ethanol you get after you convert the sugar cane which you created with 7-8% efficiency.

        I suspect that if you are converting directly to a usable energy source at around 5% it would be fairly competitive and may require less steps (capture hydrogen, compress and store, versus grow sugar, harvest, then truck somewhere to a chemical plant to covert to alcohol etc

    • Ooo, 5.5%. And it's *potentially* cheap!

      The data you are sourcing and the point you are making are not relevant to each other.

      Lifespan of product and production costs are something you would want to be talking about.

  • by alex_guy_CA (748887) <alex@schoenfeld[ ]om ['t.c' in gap]> on Monday March 28, 2011 @08:19PM (#35646746) Homepage
    See cool science article.

    Get excited.

    Read comments.

    Excitement crushed.

  • . . . some of those pills from Charles Elton that turn water into gasoline. I was going to use it in my car with a Charles Nelson Pogue carburetor. Get a bazillion miles to the gallon. Put them A-rabs out of business. But the GOVERNMENT agents stole my stuff and deny everything!

    Science fantsasy now becomes science fact.

    Or did it?

  • by RabidRabbit23 (1576305) on Monday March 28, 2011 @08:23PM (#35646772)
    I saw a presentation on exactly this technology a few years ago at a conference, not from an MIT researcher. It's a strange phenomena, but within science MIT is just one of many research institutions doing great work, but to the public it has the most significant and frequent press releases. I mean, this isn't even a leaf, it's a silicon wafer which happens to be green and splitting water using catalysts is very old. The only innovation I'm seeing here is a new catalyst, which is pretty common in these fields. I also like the token quote from Bob Grubbs who won a Nobel prize in catalyst research and thus is interviewed in every catalyst article.
    • "Only invention here is a new catalyst"?

      I would not be so quick to downplay the significance of finding a _CHEAP_ catalyst, when platinum was what was used before. That's pretty damn significant if it means mass-produced wafers costs plummet.
  • by wisebabo (638845) on Monday March 28, 2011 @08:35PM (#35646884) Journal

    According to a similar article in science daily http://www.sciencedaily.com/releases/2011/03/110327191042.htm [sciencedaily.com] it is 10x more efficient than (natural) photosynthesis.

    I'm amazed that the foundation of life on earth is so inefficient (one tenth of 5.5% is only .55%!). Is this right? If it is then I'm glad our solar devices may not have to cover up too much of our planet to generate the energy we need (but if we ever develop solar powered self-replicating nano-bots, they will totally out-compete the natural biosphere).

    Also, if this is true, then isn't this a major reason against using biofuels? I mean in addition to this inefficiency of photosynthesis, you've still got to convert it into some sort of fuel (but I guess the same is true of this artificial leaf; hydrogen is not the most practical of fuels). I guess maybe biofuels are still in the running because they can be "manufactured" very cheaply (farming and fermentation) with thousands of years of technology developed. (Or maybe it is the politics of the farming lobby).

    (I'm also amazed that they used water from the Charles river in Boston and that it still worked. I remember a time when an accidental dunking in the none-too-clean river meant a quick trip to the doctor's office for shots!)

    • by Thing 1 (178996)

      (I'm also amazed that they used water from the Charles river in Boston and that it still worked. I remember a time when an accidental dunking in the none-too-clean river meant a quick trip to the doctor's office for shots!)

      "Love that dirty water; Boston you're my home." (Thanks for the memory. :)

    • by loshwomp (468955) on Monday March 28, 2011 @08:51PM (#35646990)

      I'm amazed that the foundation of life on earth is so inefficient (one tenth of 5.5% is only .55%!). Is this right?

      Somewhere on that order, yes.

      Also, if this is true, then isn't this a major reason against using biofuels?

      Exactly. Plants are ~1% efficient at harvesting solar energy, and we have much better collectors (photovoltaics) that are much more efficient (15-20% in mass production) and generate energy in a more versatile form (electricity).

    • by Anonymous Coward on Monday March 28, 2011 @09:09PM (#35647128)

      Plants limit their photosynthetic efficiency largely because raising it too high starts raising the internal temperature, which raises the rate at which they lose water. Basically, they are tuned to gather 'enough' energy without wasting water (which is rarer for them than sunlight) rather than extracting as much energy from the sun as they can. Biofuels are usually suggested not because they are efficient, but because they are cheap and work fairly well with our existing infrastructure.

      • by yndrd1984 (730475)

        they are tuned to gather 'enough' energy without wasting water (which is rarer for them than sunlight)

        True. Except for the plants that grow in rain forests, or the ocean, or lakes, or swamps, or rivers, or ...

    • I'm amazed that the foundation of life on earth is so inefficient (one tenth of 5.5% is only .55%!). Is this right? If it is then I'm glad our solar devices may not have to cover up too much of our planet to generate the energy we need (but if we ever develop solar powered self-replicating nano-bots, they will totally out-compete the natural biosphere).

      There are many situations where efficiency does not matter at all.
      Imagine a 5x5 yards (25 plates) of "energy harvester" on your roof would give you all the

    • I am not so sure photosynthesis is inefficient.

      In one-quadrillionth of a second a plant can take the sun’s light and transfer it to the chlorophyll molecules (which give the plant its green pigmentation) in its light-harvesting centre. This process, a critical component of photosynthesis, is the most efficient energy-transfer process known, yet in many ways it is still poorly understood.

      http://www.swinburne.edu.au/magazine/5/112/photosynthesis-comes-into-the-light/ [swinburne.edu.au]

      • Sounds like BS to me, or just the random pronouncement of someone not bothering to think (but I repeat myself). A superconductor is 100% efficient, and no step in photosynthesis is going to beat that. To be more analytical, consider this: the light-to-some-particular-chemical-transformation suffers the same problem as photocells: many energy levels in, but only one energy level out. Only one wavelength can even possibly be 100% efficient, the rest are less efficient or fail to drive the reaction. QED BS.
  • According to wikipedia, http://en.wikipedia.org/wiki/Electrolysis_of_water [wikipedia.org] , traditional electrolysis is 50-80% efficient, and solar cells are ~20%.

    http://en.wikipedia.org/wiki/Solar_cell_efficiency [wikipedia.org]

    Therefore, the efficiency of using the solar panel to power electrolysis would be .2*.5 -> .2*.8 = 10% -> 16%, wouldn't it?

    So, unless there's a pretty substantial price benefit to the cell, where's the benefit?

    • by im_thatoneguy (819432) on Monday March 28, 2011 @08:55PM (#35647014)

      It's made from copper and cobalt instead of a lot of the more exotic materials used in standard photo-voltaic cells.

    • by loshwomp (468955) on Monday March 28, 2011 @09:01PM (#35647078)

      So, unless there's a pretty substantial price benefit to the cell, where's the benefit?

      As you have discovered, the economics are precisely the key to solar energy. The power density (Watts/m^2) is unimportant, except for installations with unique constraints (e.g. spacecraft). For terrestrial applications, Watts/$ is the most interesting term.

      Similarly, for economic reasons, I don't think electrolysis (or H2) is likely to succeed on a wide scale. The dirty secret of the H2 "economy" is that the hydrogen fuel cell cycle has a round trip efficiency of about 25%. A fuel cell is effectively a battery, and we already have substantially better batteries at a tiny fraction of the cost.

  • by slew (2918) on Monday March 28, 2011 @08:42PM (#35646932)

    Yesterday, Nocera reported devising a cheap catalyst that uses three different metals to form H2, getting around the platinum problem. Nocera didn't reveal the makeup of the new catalyst, as the work is not yet published, and he is in the process of patenting it.

    Before we get too excited, apparently most of his research to date has been with cobalt, phosporus, tungstun and rhodium. Not sure where all this stuff comes from, but hopefully it is widespread enough won't turn into another middle east problem.

    Also, at 5.5% efficiency, we would probably need quite a bit of this stuff which may cause some environmental issues by itself (mining, industrial polution, etc).

    As a side note, many people talk about cutting back on petrol consumption as doing our part to reduce the demand for oil which comes from the problematic middle east, but I rarely hear of folks cutting back on electronics "toy" consumption to reduce the demand for coltan (the ore where much of the tantalum for capacitors comes from) which is causing huge problems for countries like the republic of congo. Haven't heard much about the coltan topic on /. Just be cause it's "electronic" and doesn't use oil doesn't mean it's better when scaled to industrial quantitites.

    Not saying this proposed "artificial leaf" technology could definitly cause this kind of natural resource scarcity/extraction problem, but the sad fact is that if this becomes industrialized, it may not be much better than what we have today and most folks aren't even aware of the problems we have today (or even care).

    • most of his research to date has been with cobalt, phosporus, tungstun and rhodium. Not sure where all this stuff comes from, but hopefully it is widespread enough won't turn into another middle east problem.

      Production locations for:
      Cobalt [wikipedia.org]
      Phosphorus [wikipedia.org]
      Tungsten [wikipedia.org]
      Rhodium [wikipedia.org]

      Not looking good...

  • For solar power to work and be economically viable, it needs to be in orbit. Period. No solar cell, no matter how efficient is going to be viable under an atmosphere. We should have a new space race to build a space elevator... once its complete we can have all the orbital arrays we want for cheap. Near limitless power.
    • A space elevator changes everything, but until then given the astronomical cost of getting anything into orbit it would be cheaper to just build a much bigger solar array with batteries on earth.
    • For solar power to work and be economically viable, it needs to be in orbit.

      And your evidence for this is what exactly?

      No solar cell, no matter how efficient is going to be viable under an atmosphere

      Really? You do realize that almost all life on this planet derives its energy from photosynthesis which is simply an organic solar cell. Your argument seems to have a fatal flaw unless you get a lot more specific.

      We should have a new space race to build a space elevator

      So we should ignore development of solar cells which we know work (even if they aren't the most economic choice at present) in favor of the extremely unlikely chance we could develop a space elevator. An enormously complex device we aren't even sure is

      • You request evidence from me, while at the same time making a bunch of ludicrous statements like we're somehow going to recreate the worlds food chain to power your iPad. People aren't walking around all day powered by the damned sun. Think about it for a second. When your iPad uses the same amount of power as a tomato plant, we can talk.

        Provided we do not destroy ourselves before it arrives, a space elevator is inevitable. We have all of the technology to build it now with the exception of the material for
    • by Jeremi (14640)

      For solar power to work and be economically viable, it needs to be in orbit. Period. No solar cell, no matter how efficient is going to be viable under an atmosphere.

      You have it exactly backwards. Ground based solar power is economically viable now in many places, and will become more so as solar panel prices decrease, and the cost of non-renewable competition increases.

      Space-based solar power, OTOH, is a non-starter because the cost of launching solar panels into orbit is so much that you'd get a much better return on your investment leaving the solar panels on the ground. It doesn't matter how efficient the solar panels can be in orbit if it's impractical to get the

      • Solar costs 400% more than coal and nuclear. How is that economically viable? You think the average home can afford a $400/month electric bill?
  • It seems to me like this would be a good candidate for grid storage. Say you had a solar farm with both conventional solar cells and this new technology. When the sun shines, the regular solar cells both provide the product energy from the power plant, and also operate pumps that pressurize the hydrogen and oxygen coming off of the new cells. At night and when clouds come overhead, the system switches to fuel cells to burn the stored hydrogen and oxgen, regenerating the water in the process, and keeping

  • by okmijnuhb (575581)
    Gee, someone solved the energy problem. Why am I still skeptical?

Take care of the luxuries and the necessities will take care of themselves. -- Lazarus Long

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