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Science Technology

Solar Cells Get Boost 108

Posted by michael from the juiced-up dept.
An anonymous reader writes "Researchers from Los Alamos National Laboratory have tapped the efficiencies of nanotechnology to double solar cells' potential energy production. The key to the method is the use of lead selenium nanocrystals which can produce 2 electrons where 1 was produced before. Other optical applications can also benefit."
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Solar Cells Get Boost More

Solar Cells Get Boost

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  • Will this work with other materials? (Score:4, Insightful)

    by sacremon ( 244448 ) on Thursday May 20, 2004 @02:26PM (#9206866)
    The article seems to imply that the technique would be applicable to existing materials, but also seems to imply that it has only been show to work for lead-selenium nanocrystals. So will the technique of using nanocrystals work with other materials? If not, will incorporating the lead-selenium nanocrystals in a matrix of conventional material, nanocrystal-sized or otherwise, generate two electrons/photon? And finally, does the cost of making the nanocrystals make the whole thing not cost effective, other perhaps in something like spacecraft, where every once saved is of tremendous worth?

  • If I had a nickel... (Score:4, Insightful)

    by heldlikesound ( 132717 ) on Thursday May 20, 2004 @02:31PM (#9206921) Homepage
    for every time I heard about cheaper, more efficient solar cell, I could buy a solar powered calculator. Which is just about all I've seen solar power be good for at the consumer level.

    • Re:If I had a nickel... (Score:5, Insightful)

      by daeley ( 126313 ) * on Thursday May 20, 2004 @02:48PM (#9207136) Homepage
      Yeah I guess the outdoor lighting, pool heating, and housing industries (just to name a few), are pretty miniscule consumer applications. :P
      • don't forget air conditioning... solar cells are perfect for powering air conditioners because they're generally used the most in sunny weather...
        • While that makes sense (I'm assuming the cells would augment mains power given the huge power consumption of AC systems), I can't say I've actually heard of anything like this -- and I've been reading up on high-quality, high-efficiency HVAC systems since we're wrapping up the design of a fairly large new house.

          Got any names or links?
          • Here [kompass.co.uk]'s a few in the uk, i'm sure if this permantly overcase and rainy island has them the rest of the world does!

            It seems the parent site doesn't like linking to the actual search results only the heading, Que Sera Sera
          • There were some really good stories on Google News a few months ago, but I haven't been able to dig them up again since GNews only keeps stories around for 30 days.

            I managed to find a few links that talk about buildings that use/will use solar-powered AC, but they skim over the background: Duke [newbernsj.com] | Some House [theage.com.au]

            Here are are a couple of commerical solar-powered AC units: Coolmax [mx.com.au] | Solacool [partsonsale.com]

            You can find some more links if you google solar-powered air conditioning [google.com].

            • I had done some Google searches, but it seemed like everything was either generic information, or outside of the US. After talking to my builder about it, he noted that they're rarely used in in Florida (something to do with the humidity) but I'm still thinking about trying one to cool my garage, where it isn't important to get it way down to daily-living levels, but where I also don't necessarily care to spend a lot of money on electricity.

              Thanks for the links!
        • Although in the Southern U.S. it can be miserably hot
          at night too. Too bad there's not a way to generate
          electric power from high humidity.

          • Re:If I had a nickel... (Score:1, Interesting)

            by Anonymous Coward
            Too bad there's not a way to generate
            electric power from high humidity.

            Sure there is. Collect all the condensation on top of a skyscraper and use it to power a turbine down at the bottom of the building ;)
    • Yea but now you can power a TI-92 by solar power. The fact that the earth rotates makes solar power less usfull for everything because night is the time we wont get energy
      • because night is the time we wont get energy

        That's what the batteries / capacitors are for... :)
        And if you live in St. Petersburg, Russia, it's far enough north for them to have white nights.
    • Well the consumer level is not the end all and be all.
      There is little market for gas turbines at the comsumer level or hydroelectric systems but they are still important.

      Solar panels are finding more wide spread uses all the time. They are very popular with Amature radion operators. Heck I can even buy them at my local Harbor Freight store.
    • There's at least one user in California who got on a time-of-day net-metering rate program and installed a bunch of solar panels on his garage roof. His panels are cranking out watts during all of the high-rate hours (afternoon), and he gets credited at the retail rate. At night he charges his electric truck off the grid, and pays for those KWH at the off-peak rate. It's win/win; his panels pay for themselves, and the utility needs less peaking capacity.
      • One person in California hardly qualifies as a "general consumer", but I appreciate the thought.

        • Distinction (Score:3, Insightful)

          by Spamalamadingdong ( 323207 )
          Just because he doesn't fit the profile of the average consumer does not mean that he is not a general consumer; he doesn't have any billing arrangements that are not available to everyone else.

        • evolution (Score:3, Insightful)

          by Doc Ruby ( 173196 )
          If fewer neanderthals would whine "if it's so good, why isn't everyone doing it", more people would do it. And we'd get further out of the doomed hole we've dug with our paleolithic energy economy.

      • Re:Net metering.. (Score:3, Insightful)

        by fluffy666 ( 582573 )

        Although it sounds fine, it really is a problem for the power companies; retail rates not only include generation costs, but the huge effort that goes on in transmission and load balancing. To be realistic, this sort of metering should be generation costs only.

        • To be realistic, this sort of metering should be generation costs only.

          Why? Power backfed at the customer site can be sold to another customer on the same distribution line. The utility isn't losing anything. Besides, if you demand that the utility be granted all the benefits of the customer's generation you guarantee underinvestment by the customer no matter how much sense it makes to the system as a whole.

          Although it sounds fine, it really is a problem for the power companies; retail rates not only i

        • In New York we already get billed separately for generation and transmission (energy and its delivery). That lets them mark up each one separately, increasing the sum of the parts, and charge fees on each service. All in one convenient bill!
    • Here in colorado, a number of mountain homes(outside of vacation spots) have Solar. As these get higher efficiencies AND there costs drop, we will see more and more places swtiching to them.

  • Electrons are not "produced" by solar cells (Score:5, Interesting)

    by I_Love_Pocky! ( 751171 ) on Thursday May 20, 2004 @02:36PM (#9206992)
    Solar cells harness engergy by absorbing photons, which cause electrons in an atom (which are already there) to move to a higher energy state. This technique moves two electrons per photon, rather than one. The point I am making is simply that electrons are being moved, and not created. That would have amazingly different implications, as that would be creating matter from the energy in a single photon, which would only work with very high energy photons.

    • Re:Electrons are not "produced" by solar cells (Score:5, Informative)

      by SandSpider ( 60727 ) on Thursday May 20, 2004 @03:30PM (#9207728) Homepage Journal
      I have to say, this is a little picky. First of all, the article description states that the new substance "...can produce 2 electrons where 1 was produced before", so it does not imply a change in the fundamental mechanism so much as the yield. Anyone who knew how solar cells worked before reading this description would be able to make the leap that no laws of physics were being violated to produce this electron.

      Second, the description does not say that the electrons are being created at all. The dictionary definition [reference.com] of the word produce indicates, in the first entry, that produce means "To bring forth; yield", which is good enough, but skim the third entry and its example, "To bring forth; exhibit: reached into a pocket and produced a packet of matches". I think the first is more accurate, but the second indicates just how far the definition of produce does not imply creation.

      =Brian

  • The holy grail of solar power (Score:3, Interesting)

    by n1ywb ( 555767 ) on Thursday May 20, 2004 @02:45PM (#9207100) Homepage Journal
    This is it folks, this is what we've been waiting for. As it is, solar panels are a pretty marginal energy source for most applications. We've all seen the specially built vehicles that are basicly a big solar panel on wheels (some of us (like me) have even built one). We've all seen the houses with the roof covered in solar panels and they still have to buy all whacky expensive 12v high efficiency appliances and forget about an electric drier. With solar cells like these, solar power just lept from impractical to practical. Make way for the days of solar powered PDAs and cell phones, cars, houses, buses, airplanes, you name it. This is the breakthrough that will lead the way. Unless it flops, of course.
    • I'm with newbie, er, n1ywb. And I'm just as jaded. But "I want to believe" in this one.
    • It's pretty good, but solar power will still be impractical. I can see solar powered cell phones and PDAs, but that's mostly due to advaces in making those devices low power and then converging with higher effeciency solar cells. Cars? no; houses? no, you STILL need those stupid batteries, and still won't have a dryer; buses? no; airplanes? no. All the vehicles require dense power like gasoline, deisel, or hydroden fuel cells, something, not the dilute stuff of solar cells.

      However, the houses, you might

      • Re:No...it's not the "holy grail" (Score:1, Interesting)

        by Anonymous Coward
        You can use the energy generated to split common water into hydrogen (which you store) and oxygen.
        You can later, when it gets dark, use a hydrogen fuel cell. Indirect solar energy. Dense energy
        storage.

        You do realize that nearly 100% of the energy used on this planet is supplied by the sun, right?

        • sounds likle a beautiful dream, fuel for the car and electricity for the home free forever... where do i sign up
        • You do realize that you don't see the point? This isn't an article about energy storage, it's an article about energy generation. Fuel cells are great, how do they relate to the article?
          • But energy generation crosses into energy storage. His point was that you could use a hydrogen fuel cell as a way of collecting and storing solar energy while your car is not in use. Most people only drive a few hours per day. The rest of the day their car sits.

            Now there simply isn't enough energy in sunlight to power a car with solar panels. (If there was, we'd all be crispy critters.) But if you can store that energy up over a period of time, you can make your car much more efficient, perhaps even indepe
            • So place the solar panels on the garage instead of the car. You can have more surface area, and you won't have the dent in the aerodynamic and weight efficiency with having all those solar panels on a car.
              • So place the solar panels on the garage instead of the car

                Actually, I was more concerned with parking garages than home garages. The majority of city cars spend a lot of time in the deep, dark bowels of these things.

                You can have more surface area, and you won't have the dent in the aerodynamic and weight efficiency with having all those solar panels on a car.

                If the panels are built into the frame, it's not a big deal. Having a black top instead of (insert car color here) might put a dent in its style,
      • The Sun dumps 1.3KW:m^2 on the Earth; about 1KW makes it through the atmosphere to the surface at "solar noon" (directly overhead, insolation perpindicular to the surface). Efficient transmission, like local consumption, efficient storage and transduction (like hydrolysis + fuelcells), and wide deployment (like every NYC rooftop, repeated nationwide) make solar collectors much more practical than our petro economy. We're hardly pumping oil in our garages for burning in our driers. With solar, we'll eventual
    • Actually I was being totally serious. Fuck you whoever modded me down. Apperantly you missed the part where I mention that I've built my own solar car.

    • No it's not. (Score:5, Interesting)

      by Spamalamadingdong ( 323207 ) on Friday May 21, 2004 @12:02AM (#9211627) Homepage Journal
      The real issue with solar energy isn't watts/m^2 of panel, but watts/$. We have more than enough square footage to power our houses and businesses even at current efficiencies, but the capacity is still so expensive that it is very marginal. If Pb/Se nanodots can be made more cheaply than the same wattage of silicon, we'll be ahead; otherwise we won't be.

      If we get really lucky, this technology will work well at high light flux and high temperatures (~100 C). This would allow use of concentrating collectors and use of the waste heat for space heat and domestic hot water, multiplying the benefit of the collector and making the whole affair much more economical. Imagine a house that powers its own appliances, stores enough hot water for several days of hot showers and its own heating load, and on sunny days has plenty of juice left over to feed to electric cars. This house would be almost completely independent of fossil fuels and offset fuel use elsewhere, and I'll bet that we could build it now if cost was no object - if we can get 50% or even 40% efficient solar cells at $2/watt working at 100 C, we'll be there.

      • If you're aiming for 100C or above you could be generating steam. Pipe said steam through a turbine attached to a generator. You could build your own today for peanuts out of some mirrors and an old car or lorry turbocharger.

        Couldn't comment on the efficiency of a home grown system, but utility solar thermal systems have been more efficient (30% or so) at producing electricity than photovoltaics for a long time now, must be decades.
      • Powering the house, OK. Surplus electricity for an electric car, doubtful. I've yet to see a PV array of compact size that is capable of powering a typical car.

        I drive a 3000lb Sport Compact, with about a 170hp engine. There's 746 watts per hp, so that's 127KW of electricity needed for the equivalent performance. A good PV panel produces 4-6W of power per square foot in full sunlight. My car is about 15 feet long and 5.8 feet wide, giving a total horizontal surface area of about 87 square feet. If the enti
        • I drive a 3000lb Sport Compact, with about a 170hp engine. There's 746 watts per hp, so that's 127KW of electricity needed for the equivalent performance.
          That's not true at all. The electric car we built, a VW Scirocco, could do burnouts and it only had a 25hp motor with a 1500 watt controller. The secret? The motor's torque rating was up around 200 ft-lbs. HP sells cars, torque wins races, and electric motors are torquy as all getout.
          • Well... unless you have some kind of direct-drive setup, you still need the high-RPM performance. Torque to get off the line is great, but if it trails off at higher motor speeds it's not much use. (It's great for a freight truck I suppose. Not for a car.)

            Anyway, I'm not disputing your main point; I've seen writeups for several electric cars that have terrific 0-60mph specs/torque figures. And you can see some that plainly have a flat torque curve across their operating range, which means not just awesome
        • I don't know whether it's poor science instruction in the schools or general sloppiness or both, but the vast majority of people I meet (both IRL and on fora such as Slashdot) get this kind of thing terribly wrong. This has costs all around, because people who believe that feasible things won't work will resist them even if they'd benefit, and people who believe that infeasible things are workable will waste their money on frauds, waste their time and energy believing conspiracy theories about the causes (s
          • Facts are nice, but you don't need to be a rude ass about it.

            I live in LA, which is great re: insolation but terrible re: commute distances; my office is 30 miles from my home and most people live 60-70 miles from their work. People commute into downtown Los Angeles all the way from Lancaster and beyond... 30 miles a day is not realistic. I don't think Los Angeles is the only city where long commutes are a reality, either.

            I think you misread my intent as well; people ask all the time why we don't have sol

            • 30 miles a day is not realistic...

              The average commute is closer to 20 miles/day. Los Angeles is an outlier, but look at the bright side! Even by your calculations you could power a long commute entirely by the solar energy falling on a typical house's roof, and that's without postulating anything other than off-the-shelf batteries and solar panels.

              At current rates it makes no sense to try to power one's car 100% by solar electricity, but if you want to make the first 20 miles every day (or every trip)

              • Ok, sounds great. I hope we'll be seeing flexible amorphous cells at the 50% mark soon, so they can conform to existing body shapes instead of having to specifically engineer flat surfaces to mount crystalline panels.

                I think my previous experience with 5% efficient amorphous-Si cells gave me a bad perspective on things. I'd love to have a Tzero and run it primarily off solar, absolutely. The right technology is out there, but it's still not-exactly "off the shelf" yet. Close...
                • Even at 5%, you'd get 24 KWH out of 100 m^2 of roof under those conditions. If the materials were not much more expensive than conventional roofing it might well be worth it; it all comes down to $/W.

                  But some differences in quantity become differences in quality. Being able to put cells on a vehicle and get a decent amount of range out of it is enough to tip the balance for many applications. A change from 5% efficiency to 50% does that, and more.

                  Last, I'll bet that any application using nanocrystals is g

      • Re:No it's not. (Score:3, Insightful)

        by calidoscope ( 312571 )
        The real issue with solar energy isn't watts/m^2 of panel, but watts/$.

        Watts/m^2 is still important...

        The economics of solar power get really interesting when the price gets down to $1/w. For a 10% efficiency, the installed cost of the array needs to come in at $100/m^2 (~$10/ft^2) - at 50% efficiency we're talking $500/m^2 (~$50/ft^2). I would hazard a guess that the support structure and glazing would come in around $10/ft^2 (or more). The last point makes low efficiency cells kind of a non-starter, un

  • It contains lead! It contains selenium!!

    (a preview of some enviro whacko's response)

    BC

    • Earth is bad for the environment (Score:5, Funny)

      by Anonymous Coward on Thursday May 20, 2004 @03:00PM (#9207326)
      Earth is bad for the environment. It contains lethal amounts of lead, selenium. Dangerous amounts of dihydrogen oxide (which kills many thousands a year) have accumulated on its surface.

    • Re:bad for the environment (Score:4, Insightful)

      by n1ywb ( 555767 ) on Thursday May 20, 2004 @03:11PM (#9207450) Homepage Journal
      I think you're trying to make a funny, but in case you aren't... They are nano crystals. That probably means that while they're made from lead, there still isn't much lead in each cell. Also, solar cells can easily last for 100 years, it's not like they're disposable. Not to mention the fossil fuels they displace.
      • Not to mention the fossil fuels they displace.

        Just wait until the big oil companies find out about this. The project is going to get lobbied to shut down so fast, it'll make their heads spin. What a shame...
      • All true, but it in no way invalidates the grandparent post -- sillier things than that have drawn the ire of environmentalists.

        On a more reasonable note, remember that the manufacturing processes for many "green" technologies are themselves polluting and producing dangerous and toxic byproducts.
        • Extreme claims require extreme evidence: citations for these "sillier things" and toxic green manufacturing processes? Or just more FUD?
          • The fact that alternative fuel sources, such as ethenol, require more energy to grow and refine than they produce?

            Waste products produced in the production of solar cells and the fact that, even with moderate amounts of scaling up, they are not cost effective?

            And, anecdotally, the propensity for many environmental activists to also be credulous believers in pseudo-science. I realize this is a sweeping generalization, but it's hard for me to shake the image of a high percentage of protestors and activists
            • Those aren't citations, they're conclusions. Just as anecdotal as your dismissal of alternative energy as beloved by new agers. Do you disbelieve chemistry, with its alchemical roots?
              • First of all, I shouldn't have said or agreed with the term, "environmentalist wackos", as if all were. So no, I don't agree with Rush Limbaugh.

                Here are some citations about toxic chemicals in solar cell production. Granted, there are toxic chemicals used in almost any manufacturing process.

                http://www.eere.energy.gov/solar/man_pro_implicat i ons.html?print [energy.gov]

                http://www.pv.bnl.gov/art_168.pdf [bnl.gov]


                Here are a few articles about the efficiency and cost-effectiveness of ethanol production:

                http://www.fcpp.or [fcpp.org]
                • There are wackos of all kinds, including "environmentalists". At least you and I share a faith in science.

                  I've been researching the comparative pollution generated by solar manufacturing and petro (oil/coal/methane) production, on a per-joule basis. There are a lot of disconnected info resources to lash together, and the research is a part-time hobby, so it's largely inconclusive. But my low-rez info seems to favor the solar industry, especially considering thinfilm solar cells. Biomass is solar, and espec
                  • Oops on the oil company link -- I was in a hurry :-)

                    My point, if I actually had one back there, is that any issue worth discussion (that is, it is not just "cut and dried") will bring out extremist wackos from one side or the other who will distort facts and statistics and ignore information that doesn't fit their case. It is just basic human nature. Sometimes they get so far extreme that they wrap around, such as anti-abortionists commiting murder or left wingers so rabid about free speech that they wan
      • No, solar cells do not last for 100 years. They actually degrade in sunlight (very slowly) over 10-30 years, depending on their design.

        Andy Out!
        • It's my understanding that amorphous cells degrade fastest, polycrystalline cells degrade more slowly, and single-crystal cells very slowly. The output curve levels off after a while; single-crystal panels will still be going at a large fraction of their rated output after 25 years unless you hit them with enough heat or moisture to damage them in some way, such as by degrading the interconnects.
    • You're the wacko: this nonsense spouts from *your* head. While you meanwhile probably don't even notice a factory spitting actual poison into your air, much less those which have been fixed to pollute less. Stop attacking environmentalists, and realize that you are one, like everyone else who lives in an environment.

  • Price? (Score:4, Insightful)

    by phlack ( 613159 ) on Thursday May 20, 2004 @03:37PM (#9207806)
    Unfortunately, the article didn't mention price, at least not directly. It stated "would become practical in 2-3 years", which I can only assume means they'd be the same price as today's cells.

    It is indeed a shame that more interest in this technology doesn't exist. The lack of responses to this article is pretty disappointing, especially since I would think /.ers would be one of the main supporters. Doubling the output of cells is a definite improvement.

    I remember reading somewhere (IIRC one of the Real Goods [realgoods.com] Source Books) that had the phrase similar to "Solar Panels will never become widely accepted until they are available from your local Home Depot [homedepot.com]." This definitely rings true. Aside from the solar powered walkway lights (total garbage), they have very little to offer there. Solar Cells need to be cheaper and more powerful if people are going to use them.

    It's good to see that progress is being made, though, as this article describes. Perhaps one day it will indeed become practical to use solar panels. Until then, we're stuck with calculators.

    • Man, I have to stop there on the way home tonight to pick up more bits and pieces for the renovations we're making to our new house-- I *wish* I could just take a carload of solar shingles home with me, and plug them straight into some pre-existing standardized rooftop wiring grid.

      It's currently a long-term win to buy panels, but it's too steep an up-front investment for most people. $20K with payback over decades is more than most people are willing to do. Perhaps the power companies could invest in peo
      • Nope, it's not a long-term win. 1. The cost of the solar cells divided by the KW*H of energy produced is about 3x the price of off-the-grid electricity. 2. Solar cells are made using NASTY chemicals. All those green freaks don't realize we generate 10x the pollution making solar cells as we do generating the same amount of electricity for grid-use. Andy Out!
        • All those green freaks don't realize we generate 10x the pollution making solar cells as we do generating the same amount of electricity for grid-use.

          This turns out to no longer be true. Look up thin-film cells, which are both cheap and low materials use.
        • Your numbers are old. The point for energy break-even (when the amount of power produced is more than the power used to make them) is roughly 2-4 years, and their cost break-even is well within their 20-30 year lifetime. How long this takes depends on the electric rates in your area, of course.

          A batteryless grid-tied system will break even on cost in roughly 6-12 years. Most people just can't stomach the large up-front cost for such a long payoff time. I can't, although I intend to as soon as I have an

          • their cost break-even is well within their 20-30 year lifetime. How long this takes depends on the electric rates in your area, of course.

            True. Some places where power costs $.30/KWh (such as some islands) would yield a quick return. Other places, such as here in Central Florida with Florida Flicker & Flash [fpl.com] charge ~$.08/KWh, and thus the return would take significantly longer. Less if the state gives a rebate or tax credit of some kind (Florida does neither, to my knowledge).

            But I agree with a p

            • There is a company putting them into shingles. I was just bemoaning the inability to buy them at my local Home Depot-- since as we all know, home improvement projects always require more than one trip back to the store.

              Check out sunslates [atlantisenergy.org] for one example-- I seem to remember there being another, but the name escapes me. They go on like slate roofing tiles.
    • Unfortunately, the article didn't mention price, at least not directly. It stated "would become practical in 2-3 years", which I can only assume means they'd be the same price as today's cells.

      It could just as easily mean "2 to 3 years before we can produce entire solar cells with this tech".
    • Canadian Tire doesn't sell 2x4s but they do sell other building supplies and tools apart from car stuff.
      Go here [canadiantire.ca] and enter SOLAR as the keyword. (enter postal code: K1J 1J8)

      I found this:

      45W Cottage Solar Panel Kit
      Special Offer
      Product# 11-1588-0
      View larger image
      Price $499.99
      Availability
      In Store Online

      Qty.
      *

      Harness the sun's power to run small appliances (both AC and DC) such as TVs, lights, computers and to recharge your 12V DC batteries in your RV, boat or cottage. The 45-watt Cottage Solar Panel K
    • How much energy is consumed by the thin-film solar cell manufacturing process, per square meter of produced cells? What is their efficiency curve over incident light wattage? How many years do they last? Ergo, what is the net energy production from their use? Many thermodynamic processes merely distribute energy costs to where they're not noticed, but still affect. If we burn oil and coal to manufacture a net-loss solar cell, we're digging ourselves deeper.

  • Not quite there yet (Score:5, Insightful)

    by Retric ( 704075 ) on Thursday May 20, 2004 @04:35PM (#9208556)
    From what I can tell there not manufacturing solar cells using "lead selenium nanocrystals" but rather they found a method of detecting "impact ionization" via the delay between the photon impact and electron emissions. They then tested several substances and discovered that lead selenium nanocrystals produced impact ionization on close to 100% of photon impacts.

    So if you really want to know what's going on you need to discover how efferent lead selenium solar cell's are and what it takes to mass produce lead selenium nanocrystals in a cheep long lasting solar cell.

    So it's a long way from producing 60+% efficient solar cells but it's still cool.

    • Re:Not quite there yet (Score:4, Informative)

      by Christopher Thomas ( 11717 ) on Thursday May 20, 2004 @07:16PM (#9210041)
      So if you really want to know what's going on you need to discover how efferent lead selenium solar cell's are and what it takes to mass produce lead selenium nanocrystals in a cheep long lasting solar cell.

      Nanocrystal films would typically be grown by chemical vapour deposition (chemical constituents react as a gas at low pressure, seed crystals grow in-flight, and grow further after being deposited).

      The problem is that it's very hard to produce crystals that small (they tend to keep growing after being deposited, because the source materials are still present - this is how you normally do CVD, actually). You also have difficulty producing a narrow range of sizes, because that requires that the growing environment of each crystal be identical.

      Still an interesting discovery, though. The fabrication problems will eventually be solved.

      What's especially interesting is looking at what happens when you fabricate oher types of semiconductor microstructure or nanostructure by more conventional techniques. As the size of a feature shrinks, you can no longer pretend it's near-infinite in extent when figuring out what the energy levels are within the crystal. This has already been used to alter the properties of silicon (fabricating LEDs in silicon, which normally emits very poorly due to having an indirect bandgap). Quantum wells, wires, and dots are an extreme case of this (dimensions comparable to a few electron wavelengths). When lithographic feature sizes start approaching this range, lots of new devices will be possible in mass-market chips that are only possible now if you have an e-beam lithography setup handy.
      • If you want to fix the size of the nanocrystals, precipitate them using wet chemistry; nucleate a whole bunch of them all at once, and they will stop growing when the materials are depleted from the solution. Taking the suspension of nanocrystals and assembling them into a working device is another matter.
  • until we can expect one of the big oil companies to obtain the patent to this and kill it like they have with the all the other dozens of promising recent solar and other clean energy technologies? I'm almost certain GW's boss Dick Cheney will find a way to make it happen, one way or another.
    • The big "oil" companies are major investors in new energy technologies, not to suppress but to turn them into profitable businesses. Thay are doing a lot of research on their own, and buying companies up as well. They all anticipate the growth of demand for alternative fuels, solar, and wind, and so forth. They are jockeying for position in that future marketplace.

      I don't recall the number, but IIRC together these companies have invested multiple Billions of $ in advanced energy systems. This is not th

  • Storage Storage Storage (Score:5, Interesting)

    by tino_sup ( 460223 ) <tino_sup@aichohteeemayeell.com> on Thursday May 20, 2004 @07:50PM (#9210295) Homepage Journal
    Renewable energy has made phenomenal leaps, but the storage restriction is the crux. Efficiency is great, and is a move in the right direction. What remanins is the development of efficient and economical storage devices. Imagine your car operating for a week on a one hour solar charge stored in a device the size of 4 D sized batteries.
    • I think hydrogen may have potential in that application. It's a reasonably efficient way to move energy around. You have to use some kind of energy to produce the hydrogen, and it would be far better to do it with solar than with fossil fuels.

      Or it might be a way to bridge the energy gap in ethanol (either for combustion or in fuel cells), where currently you have to burn an amount of fossil fuels to produce the ethanol, some say more than you get out.

      At least, I hope one of these works out, or some oth
      • I think hydrogen may have potential in that application. It's a reasonably efficient way to move energy around. You have to use some kind of energy to produce the hydrogen, and it would be far better to do it with solar than with fossil fuels.

        Solar cells are actually very good for this purpose, as electricity is produced directly, as opposed to having to be converted from another energy form (like heat, in the case of a coal or oil fired power plant).

        You can produce hydrogen from fossil fuels fairly effi
      • Hydrogen would be great if it wasn't so inefficient to produce.

        The battery problem has been solved for vehicles. It was solved when NiMH batteries became available. The issue is the cost of manufacture and actually getting someone to build the things.

        Seriously. These guys have viable vehicles:

        http://www.solectria.com/products/accomp.html

        249 miles on a single charge for their *in production* Solectria Force car, my petrol car does about 240 miles before I have to fill up. They have a prototype called the
    • Imagination is the only domain in which your comment can ever be real. Even at 100% efficiency, 1 hour of solar energy will run a small car at highway speeds for less than one hour. Even the most powerful chemical reactions cannot store enough energy in the size of 4 D cell batteries to run a car for a week.

    • Storage can be TOO good (Score:4, Interesting)

      by Spamalamadingdong ( 323207 ) on Friday May 21, 2004 @12:22AM (#9211790) Homepage Journal
      Imagine your car operating for a week on a one hour solar charge stored in a device the size of 4 D sized batteries.
      Let's see, if you drive 250 miles a week and get 25 MPG, that's 10 gallons of gasoline or about 60 pounds. Gasoline has about 9 times the energy of combustion as TNT (because TNT carries its own oxygen). So: Imagine the energy of several hundred pounds of high explosive in a device the size of 4 D-size batteries. Not so appealing any more, is it?
    • One which never wears out. Compress air up to 300 or more atmospheres. It's much much cheaper to buy a pressure vessel than it is to buy batteries which hold an equivalent amount of energy and far far more efficient than electrolysis. Most useful for stationary purposes, generators etc due to the size and weight of the pressure vessel. (in fact you're using heat to store the energy)

      P.S. Battery powered cars have been able to run for 250, 300 miles for a good 7 years or so with a battery life of around 100,

      • P.P.S. why do Americans call petroleum, gas? It's a liquid at ambient temperatures...


        Gas is short for gasoline. I am not sure of the word's origin.

      • gasoline (Score:1, Offtopic)

        by boarder ( 41071 )
        Why do Americans call petroleum gas?
        Why does the rest of the world call gasoline petroleum?

        Gas is short for gasoline, which is what we put in our cars (well, it used to be... now it is a mix of gasoline, ethanol and other crap). It's boiling point is well below that of water and evaporates rather quickly (gas fumes are much more explosive than liquid gas).

        Petroleum is "a thick, flammable, yellow-to-black mixture of gaseous, liquid, and solid hydrocarbons that occurs naturally beneath the earth's surface,
      • Others have already pointed out that "gas" is short for "gasoline." I just wanted to add that the word in Spanish is gasolina, in Japanese gasorin, in German gasolin, in Portuguese gasolina, so the Americans are hardly alone. In fact, the only major language that uses petrol besides British English is Afrikaans. Most European languages use the word "benzine" or a derivative thereof.

        Point being that it appears "petrol" is the odd man out.
    • Depending on the size of your vehicle, it takes between 15-25 kilowatt-hours of power per hour of use. If you used your car an average of 2 hours per week, you would need to store between 200-350 KWh of power in those batteries. To get that much power in an hour from 50% efficient solar cells would require around 600 square meters of solar panels. in other words, your solar panel would need to be a square 75' on a side.

      If you allowed for a four hour charge, you would only need a panel of 150 square meters,

  • Real implications of cheap solar power (Score:3, Interesting)

    by justanyone ( 308934 ) on Friday May 21, 2004 @12:22AM (#9211791) Homepage Journal
    Let's look at what the real implications of cheap solar power are:
    • Vast reduction in cost of electrical power
    • reduction in demand for coal products to approx. 5% of current usage due to solar plants supplying grid (excess produced by nuclear);
    • immense pressure to develop better batteries for use by cars;
    • demand for tech to turn electrical power plus (whatever) ingredients into natural gas (cars powered by methane emit only CO2, not other nasty stuff, plus infrastructure there - existing cars can run on natural gas for $300 conversion kit);
    • vast diminishment of political and economic wealth of many arab and persian) nations plus Russia, Venezuela, and some african countries;
    • vast reduction in demand for hydro power in Northwest, hydro dams that are not useful for irrigation & flood control are torn down;
    • home power kits still possible, but since 50% of cost of off-grid solar-cell electrical is electronics (not the cells), this isn't a major factor for most people;
    Feel free to fill in your implications as replies, or refute these...
    -- Kevin J. Rice
    • Let's look at what the real implications of cheap solar power are:

      But, the interesting fact is that there are industries, countries and individuals that stand to lose billions of dollars in income if/when such advances in solar energy take place. And billions of dollars they make now buy _a_lot_ of influence. So, don't expect the changes to happen overnight, or any time soon...
    • "immense pressure to develop better batteries for use by cars;"

      The battery technology exists. It is simply expensive due to lack of manufacturing capacity.

      The 80, 90 mile ranges you hear about for electic cars? Lead acid batteries. That's what... 200 year old technology?

      NiMH, LiON, and even better LiS batteries are here, now, but are manufactured in quantities too small to make them feasable in a car. It's *purely* down to the manufacturing costs.

    • Let's look at what the real implications of cheap solar power are:

      • demand for tech to turn electrical power plus (whatever) ingredients into natural gas (cars powered by methane emit only CO2, not other nasty stuff, plus infrastructure there - existing cars can run on natural gas for $300 conversion kit)

      Even though burning a perfect mixture of pure methane and pure oxygen do produce only CO2, a car running on pure methane would also produce nitrogen dioxide (NO2) [epa.gov], simply because we would use air inste

    • Let's look at what the real implications of cheap solar power are:

      One very valuable use for cheap electricity is desalinating seawater. Normally arid areas bordering on an ocean or large sea (think places like Baja California, North Africa, even Saudi Arabia) will have access to significant amounts of very fresh water - probably won't be cheap enough for rice farming, but certainly cheap enough for moderately high-value crops.

      Reverse osmosis is not as energy intensive as you might think - current technol

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