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Power Science

40% Efficiency Solar Cells Developed 357

gtada writes "A story published at Physorg.com discusses recently published research into the fabrication of solar cells that surpass the 40% efficiency milestone. Such devices would be the high water-mark to date, and hint at the possibility of even more effective technology. 'In the design, multijunction cells divide the broad solar spectrum into three smaller sections by using three subcell band gaps. Each of the subcells can capture a different wavelength range of light, enabling each subcell to efficiently convert that light into electricity. With their conversion efficiency measured at 40.7%, the metamorphic multijunction concentrator cells surpass the theoretical limit of 37% of single-junction cells at 1000 suns, due to their multijunction structure.'"
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40% Efficiency Solar Cells Developed

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  • by timeOday ( 582209 ) on Friday June 01, 2007 @06:34PM (#19358717)
    There is really no shortage of sunlight anyways. If only solar cells could be made cheaply. I suppose this will be great for satellites though.
    • by Volante3192 ( 953645 ) on Friday June 01, 2007 @06:37PM (#19358755)
      You say there's no shortage of sunlight, but I'm sure they said that back in the days of coal burning plants. We need our solar cells to be as efficient as possible.

      If we run out of coal, we can adapt. But if we blow all our sunlight on inefficient solar cells, the consequences would destroy life as we know it!
    • by provigilman ( 1044114 ) on Friday June 01, 2007 @06:45PM (#19358833) Homepage Journal
      There's no shortage sunlight, true...but there's a shortage on space. Our energy needs to continue to grow more and more every year, theoretically it could get to the point where we have to cover large amounts of the planet's surface with solar collectors. The more efficient each individual collector is, the fewer we need and the less space they'll take up.
      • by SnowZero ( 92219 ) on Friday June 01, 2007 @07:05PM (#19359017)
        While space will eventually be a problem, I think cost is still the limiting factor right now. How many houses can afford to cover their entire south-facing roof with panels right now? If you see panels on a house, its usually only covering a fraction of the available area, which implies the limit is cost.

        Right now, we've got ~40% efficiency panels which are very expensive, and 1-2% panels which are cheap to make. I think the real breakthrough will be when we can make 20% efficiency panels that are inexpensive enough to cover a roof. So, in the long run, you are right that space will be the overriding factor, but right now it's cost-per-watt that is the biggest problem.
        • by bill_mcgonigle ( 4333 ) * on Friday June 01, 2007 @07:43PM (#19359367) Homepage Journal
          I think cost is still the limiting factor right now.

          Yeah, there's a guy in NJ who went completely solar for his energy needs and spent about $400K on the system, not counting maintanence costs.

          If only Moore's Law applied we'd all have a setup like that in ten years.
          • ...maybe not Moore's law, but economy of scale can definitely reduce costs.

            I think there was a (senior) VP of HP that tried to bring the former chip manufacturer's strengths to bear on this problem. Essentially using their fabs to make solar panels (picture the needs for vast amounts of silicon wafers and large scale glass manufacturing). And to turn those panels into "cookie cutter" plants that utility companies could purchase.

            Unfortunately, it got torpedo'd. Thinking too far outside the box I guess....
          • Re: (Score:3, Insightful)

            by billcopc ( 196330 )
            Part of the problem is we're still working against each other when it comes to energy. $400K of solar power equipment isn't the cost, it's the sale price. How much of that went to the various middlemen involved ?

            If we keep treating energy efficiency like a luxury, it won't be long before we value energy above life itself. Forget 1984, it'll be more like Mad Max.
            • Re: (Score:3, Insightful)

              I'm sorry, that's just paranoid. Check out the financial statements of Evergreen Solar, or Corning, two of the producers of panels. They're not printing money. It is a fact that it is not yet economical to power your house with solar, and it's due primarily to the cost of manufacturing the panels. The costs -are- declining, but it's not yet cheaper than coal, hydro, or nuclear. Of course, those sources have significant external costs that are not factored into their market price. When we think through
          • Re: (Score:3, Interesting)

            by mdsolar ( 1045926 )
            A lot of the high ($400K) price tag was for hydrogen storage and use in a fuel cell. The sola power portion was much less than this.
            --
            Rent a net metered system at a fixed money saving rate: http://mdsolar.blogspot.com/2007/01/slashdot-users -selling-solar.html [blogspot.com]
        • Re: (Score:3, Informative)

          by mobby_6kl ( 668092 )
          Of course it's a cost/watt thing, except that the cost of the panel is not the only thing in the "cost" part there. There are a lot of overhead costs associated with solar power such as installation and maintenance, plus there's the fact that you usually can't cover the whole roof with them since roofs are often used for other useful purposes. These costs can be reduced by using fewer (smaller) more efficient panels. Also, the per m2 panel prices can go down only that far (unless Al Gore subsidizes them), s
        • Re: (Score:3, Insightful)

          by cerberusss ( 660701 )
          In my opinion, people themselves shouldn't buy panels. Due to installation costs and scale, this makes panels extremely expensive. Compare that to the cost of PV power stations [wikipedia.org] and you'll see that the pay back time is muuuch shorter than for the individual man.
      • Re: (Score:2, Insightful)

        by Rei ( 128717 )
        There will be no shortage of residential, commercial, and industrial roof space, nor a shortage of parking lots (for photovoltaic sunshades), in the forseeable future.
      • There's no shortage sunlight, true...but there's a shortage on space. Our energy needs to continue to grow more and more every year, theoretically it could get to the point where we have to cover large amounts of the planet's surface with solar collectors. The more efficient each individual collector is, the fewer we need and the less space they'll take up.

        Very true - but that's not clearly the case with the collectors discussed here. While the individual cells are more efficient - they gain part of that

      • by jessecurry ( 820286 ) <jesse@jessecurry.net> on Friday June 01, 2007 @11:22PM (#19360605) Homepage Journal
        Interestingly enough the entire planet already is covered with solar collectors... well all of the planet that is "untouched" by man.
        It would be great if we could produce solar cells that reduced the amount of CO2 and produced electricity for man to use. If we could do that then we would really not make much of an impact as we "developed" lands.


        ** keep in mind that the above comment disregards the other effects of "development"
        • Re: (Score:3, Informative)

          by MikeBabcock ( 65886 )
          What, you mean plants? (They absorb solar energy and CO2 too)

          For you urbanites, they're the green things.
    • Re: (Score:3, Interesting)

      by spun ( 1352 )
      That's exactly what I was going to say. I believe that most solar cell manufacturing processes would scale well, so they could be made cheaply if there was enough demand to justify scaling production up. Where could that demand come from? What if the Federal Government mandated that all Federal buildings had to be solar powered? The rest of us would reap the benefits of economy of scale. Now, if we could only figure out some way for the oil companies to reap massive profits from such a scheme, I'm sure it w
      • by Rei ( 128717 )
        Some parts of America average 8 times more insolation than others. Not a good plan. Single-source power ideas rarely are.

        Economies of scale certainly do apply to solar cells, but not indefinitely so, nor anywhere even remotely close to a linear relationship. There's also the problem, when you really get down to it, of supplying dependency chains when resource production can only increase so fast and economical deposits are finite in scale.
      • Re: (Score:3, Informative)

        The problem is that the materials used to manufacture these cells are expensive. Economy of scale reaps the greatest benefits where the basic materials are/can be plentiful and the manufacturing is the major cost. However, if the cells are made of pure gold laced with diamond-studded glue (probably not, although the article never says what they're made of), then a larger amount being manufactured is going to have either a minimum reduction in cost or a large inflation of the cost (plus wedding rings will be
        • by timmarhy ( 659436 ) on Friday June 01, 2007 @09:38PM (#19360089)
          no the main material is silicon and it's plentiful, the expenive part is the production, it requires a LOT of processing and quality control. people keep rambling on about moore's "law" but fail to realise the price of a cpu hasn't really fell very much at all in 10 years, they've just gotten faster (which is all moores prediction is to do with). in the case of solar panels this will NOT help them sell. they need to get much much cheaper for adoption to happen.
      • by thpr ( 786837 ) on Friday June 01, 2007 @10:11PM (#19360273)
        I believe that most solar cell manufacturing processes would scale well

        Not particularly. Because they rely on semiconductors, they only scale as well as the fabs to build them. The problem has been that the solar industry uses plants that are at the end of their semiconductor chip fabricating life; thus they do not wield great efficiency due to small wafer sizes. They also suffer from the base challenges of dealing with silicon wafers (raw cost of wafers, dicing costs, etc.) The same cost problem exists with LEDs. It's interesting to note how GE is focused on cost of production in OLEDs rather than their efficiency on GE's Global Research Blog post [grcblog.com]. Following that analogy, it's not the 40% efficiency that will launch solar cells, it's 10% efficiency at 10% of today's cost (It's about cost/kWh).

        Now, if we could only figure out some way for the oil companies to reap massive profits from such a scheme, I'm sure it would happen in no time.

        You mean oil companies like BP and Royal Dutch Shell? ... two of the top 6 producers of solar cells? [iea-pvps.org]

        I'd note that most oil companies do have lots of research into alternative (non-oil) energy. It's just hard to see in their financials because oil is so lucrative. The major one that realy gets criticized for its lack of investment in areas like solar is ExxonMobil - and the reason they don't is probably the same reason that Cisco doesn't tend to develop most of its revolutionary technology inside the company. XOM and CSCO both have tons of cash, tons of cash flow and a well-priced stock giving them the ability to simply buy a producer of new equipment if it becomes a valuable market. Why bother to spend tons of money on basic research when you can let the newcomers fight it out in the market and just buy the leader when the time is appropriate? As strange as it is, that's R&D economics at many large industry-leading corporations. It's "efficient outsourced innovation" [businessweek.com].

    • Re: (Score:3, Insightful)

      by lachlan76 ( 770870 )
      If the solar cells are more efficient, then the panels will produce more power, and therefore less will be needed. Also, less space will be needed, less equipment, etc. etc.
    • by Anonymous Coward
      The cost of the cells is only one part of the expense of the system. With sufficiently inefficient cells, they could never be installed economically. IIRC, it is possible to make amorphous cells for just about free but there's just no point because they are so darn inefficient.

      http://en.wikipedia.org/wiki/Solar_cell [wikipedia.org]
    • Re: (Score:3, Funny)

      by Fringe ( 6096 )

      There is really no shortage of sunlight anyways.
      I live near Seattle. We typically do have a shortage of sun. On the other hand, we lead the nation in hydropower. And espresso-power.
      • Re: (Score:2, Insightful)

        I live near Seattle. We typically do have a shortage of sun. On the other hand, we lead the nation in hydropower. And espresso-power.,/i>

        I live in Seattle.

        This is an incorrect statement. Even when we have cloud cover (and man is it dreary here for 8-9 months of the year), we have 70 to 80 percent of the sunlight you would get on a sunny day.

        That's why when you buy Green Power from Seattle City Light, it goes to build wind turbines and also solar cells for schools, public buildings, and bus shelters. So
        • Re: (Score:3, Informative)

          by Rei ( 128717 )
          This is an incorrect statement. Even when we have cloud cover (and man is it dreary here for 8-9 months of the year), we have 70 to 80 percent of the sunlight you would get on a sunny day.

          No, *that* is an incorrect statement. I think you're mixing up UV transmission with visible spectrum transmission. Clouds absorb and reflect 35-85% [phelsumania.com] of radiant energy. Even worse, cloudy-day sunlight is diffuse, so you can't optimize your panel angle effectively and you have no choice but to suffer flat plate losses.

          Clou
          • by WillAffleckUW ( 858324 ) on Friday June 01, 2007 @07:55PM (#19359465) Homepage Journal
            I'm sorry, but you are decidedly incorrect. The amount of sunlight that can be converted on a fully overcast day in the Seattle-Tacoma region is normally in a range of 70 to 80 percent for photovoltaic solar cells in terms of solar energy.

            You might want to investigate it yourself - just pop over to Seattle City Light on the City of Seattle website and read up on it.

            Now, the solar cells we use to POWER some of our public buildings, bus shelters, and schools here are not as efficient as the 40 percent that this Letter in Applied Physics speaks of, but they are about half as efficient.

            Cloud cover as you understand it, depends on visible light spectra. The solar cells absorb far wider bandwidths, at least the ones in common use here.

            If we were a snowbound or ice-storm city like many others - which we are not - it is possible that your statement would be less inaccurate, as the ice crystals and heavier cloud formations might refract more of the effective solar energy, but we tend to only have a mild drizzle due to the consistency of our cloud cover.

            Or haven't you noticed?

            Don't believe me? Go look at the bus stops with LED readouts along N 45th, some of the public schools (including two my son went two and the high school he's in now), and even Seattle Center's public meeting rooms.

            See - solar cells. Perfectly happy solar cells.

            Some people use solar water heaters on their rooftops here, and if you look around Phinney Ridge you'd see a few of them. There's a reason they're frequently referred to in the Seattle Times supplements on Green Houses - people USE them. Because they make sense here.

            Here endeth the lesson.

            • by jd34 ( 599131 ) on Saturday June 02, 2007 @01:12AM (#19361079)
              Why is this moderated "Informative"? I almost thought it was sarcastic... but I fear he is serious.

              The amount of sunlight that can be converted on a fully overcast day in the Seattle-Tacoma region is normally in a range of 70 to 80 percent for photovoltaic solar cells in terms of solar energy.
              70 to 80 percent of what? Of the efficiency it has when it is operating at full power, perhaps... but quoting percent of efficiency is highly misleading. If this statistic is meant to refer to 80 percent conversion efficiency (an interpretation which the quote does not rule out) then it is deep in the realm of lies, damned lies and statistics.

              Cloud cover as you understand it, depends on visible light spectra. The solar cells absorb far wider bandwidths, at least the ones in common use here.
              Actually, the spectral response of crystalline silicon photovoltaic devices is remarkably similar to the visible spectrum. Some thin film technologies extend a bit more into the infrared, and their efficiency is boosted from, say, 6% to perhaps 6.5% under cloudy conditions... but since that is an output that is divided by a small input, it is still just a small output. In the annual energy accumulation it doesn't make nearly as big a difference as the thin-film manufacturers would like you to believe.

              Go look at the bus stops with LED readouts
              As though reading such devices, installed at lowest cost by the people who have an interest in inflating the value of their product, should be convincing? Not.

              The fact of the matter is that no matter how efficient a cell is on cloudy days, there just isn't as much energy available on cloudy days as on sunny days. A heavy overcast probably has 15-30% of the energy as a sunny day, which is certainly better than zero but is a major hit if you can't count on some sunny days to "make hay" on.

              Also, efficiency matters to people with limited space in which to install solar arrays. Of course, current production crystalline technology has cells with efficiencies in the high teens, but when packaged the overall efficiency usually drops to the low teens for a number of unavoidable reasons.

            • Re: (Score:3, Informative)

              by Alioth ( 221270 )
              70-80% Where do you get those figures from? They are completely WRONG for today's solar technology.

              I have a monocrystalline panel as a test project. It's a new, high quality panel. Monocrystalline is the most efficient that's easily available on the open market at the moment.

              Here are the real figures, from a real panel powering a real load:

              Direct sunlight, absolutely perpendicular to the panel: 100% of peak
              Two hours before or after mid-day on a hazeless cloudless day: 40% of peak
              Light cirrus cloud, at mid d
    • It depends on what you want to do. If you want something portable you can charge your PDA, smaller is better. If you want to have a charger on cars, smaller is better. If you want to use part of your roof, smaller may be better.

      If you're talking about massive power-plant-style solar arrays, perhaps size isn't too much of an issue, but even the more power you can generate in less space means less work and more scalability.
    • There is really no shortage of sunlight anyways.

      But there is a shortage of space, and load bearing capacity, on my roof, which could make these desirable over less efficient models.

      I suppose this will be great for satellites though.

      There is no shortage of space in outer space.

  • Buy gallium futures? (Score:5, Informative)

    by Animats ( 122034 ) on Friday June 01, 2007 @06:35PM (#19358727) Homepage

    It's another gallium-based technology. That's going to limit it. There's just not that much gallium available. 30%+ efficient cells using gallium have been around for a few years, but other than on spacecraft, and the Stanford Solar Car, they're too expensive to be useful. They talk about "concentrator cells", but that means mirrors and trackers, running up the system cost.

    Citation: King, R. R., Law, D. C., Edmondson, K. M., Fetzer, C. M., Kinsey, G. S., Yoon, H., Sherif, R. A., and Karam, N. H. "40% efficient metamorphic GaInP/GaInAs/Ge multijunction solar cells." Applied Physics Letters 90, 183516 (2007).

    • If they're able to adapt the multi-junction technology to the consumer grade cells, though, that could be worth it by itself. Seems to me something that they might be able to use prisms for, if all its doing is scattering the wavelength to the more specialized cells.

      (Warning: I'm quite probably talking out of my ass...but it sounds interesting and remotely possible with my rudimentary knowledge.)
      • Prisms would be perfect. A rainbow and extensive use of gallium.

        Now we know what's on the gay agenda for today.

    • To the moon Alice! (Score:4, Interesting)

      by headkase ( 533448 ) on Friday June 01, 2007 @07:40PM (#19359341)
      All the more reason we need to establish reliable mining on the moon. Concentrations [sciencemag.org] on the moon are about 80% higher than on Earth. You know, there is a lot of history ahead of us and maybe Lunar mining would allow future infrastructure that at this point in time boggles the imagination.
      • Concentrations of Lunar gallium are wrong (actual 3 to 60 ppb Moon; 80 to 100 ppb Earth) but the next sentence is still valid. I suck.
  • no (Score:5, Insightful)

    by wizardforce ( 1005805 ) on Friday June 01, 2007 @06:39PM (#19358777) Journal

    Suppose I just dump a bunch of Algae in a pond, then scoop off the top flotsam once a week, dry it in the sun, and then burn it? Would this be more or less than 40% efficient?

    not even remotely. plants are efficient at converting photons to an immediate energy source but the vast majority is used to keep the existing tissues alive and functioning. esimates I have seen for the efficiency of converting light, CO2 and water into biomass ranges from less than 1% to 5% depending on the species.
  • Efficiency (Score:5, Funny)

    by robably ( 1044462 ) on Friday June 01, 2007 @06:42PM (#19358801) Journal

    With their conversion efficiency measured at 40.7%, the metamorphic multijunction concentrator cells surpass the theoretical limit of 37% of single-junction cells at 1000 suns, due to their multijunction structure.'
    40.7% efficiency at 1000 suns, so with only one sun that makes them... 0.0407% efficient.

    Hmm.
    • I suspect that they are intended to have sunlight focused onto them, rather than just put out into the sunlight.
    • Re:Efficiency (Score:5, Informative)

      by dteichman2 ( 841599 ) on Friday June 01, 2007 @07:07PM (#19359055) Homepage
      The solar cells are extremely expensive due to the Gallium in them. It's cheaper to have 1 solar cell with a thousand mirrors reflecting onto it. Hence the stellar luminosity of 1000.
    • ...and if you concentrate the sunlight 1000 times, then the thing will melt...
    • Re: (Score:3, Interesting)

      by taniwha ( 70410 )
      well think about it - there are photons kicking electrons/holes around - at some power density there will be more photons than electrons/holes available at any instant and the efficiency will drop - I suspect they are bragging that it still works with light at that intensity (as someone points out Ga is expensive ...)

      What isn't being trapped by jumping electrons (that other 60%) is going to go into heat - what we need is a heat engine on the back side of the cell recovering that other 60% ...

      • Re: (Score:3, Informative)

        by njh ( 24312 )
        Unfortunately a heat engine that would use even a significant amount of that 60% heat is going to require temperatures greater than the operating temperature of the solar cell. The solar cell itself is in fact a heat engine operating at roughly 42% of the theoretical maximum efficiency, which compares well with all but the biggest fluid based engines.

        However, if you want heat, rather than work, you should be able to collect all of that 60% - thermal desal, domestic hot water, space heating - all are easily
    • So what, now we're supposed to detonate nukes in front of our solar panels for maximum efficiency?
  • The main issues (Score:3, Insightful)

    by Erioll ( 229536 ) on Friday June 01, 2007 @06:43PM (#19358811)
    The main issues with this are:
    1. Efficiency: This article talks about brightnesses of 100 suns. Well what about 1 sun? Or fraction of that (cloudyness)? Are these efficiencies realized then too? If not, does the technology still work at or near where that is?
    2. Power cost: I've seen it said that many solar cells don't give back the energy required to manufacture them. By that I mean, acquiring the materials (mining, etc), refining them, and manufacturing them all take energy. How many days/months/years would it take to "pay back" the cost of manufacture, in energy?
    3. Temperature performance differences: How does it perform in low (or high) temperatures? A lot of us live in places where it gets cold for long periods of the year. This also has the associated problems with snow build-up, and getting that OFF of the panels.
    4. Monetary cost: How much will this cost at the consumer level, for which wattages? How big would they have to be to cover some typical consumer usages?
    5. Power storage: With solar, it all eventually comes back to storing the power, as they obviously don't operate in darkness. So how much would the batteries cost (initially, and in maintenance) to make this a viable power solution? How much wattage would you need to have enough "storage" for nighttime? Or more practically, for a few cloudy/rainy days in a row?
    Some of these issues are universal to ANY solar technology, but some of them are specific to this as well. All need real answers.
    • Re:The main issues (Score:4, Insightful)

      by sampson7 ( 536545 ) on Friday June 01, 2007 @07:14PM (#19359119)
      There are a lot of problems with the premises of your questions. But a couple of the easy ones:

      1) Efficiency and measures of "suns": As others have explained better than me, this basically means that they are using mirrors to "collect" the sun power and focus it.

      3) Temperature: Solar cells tend to work better in colder weather, as you have less heat transfer loss. It just so happens that many (but not all) places with lots of sunlight happen to be hot -- but cold weather is actually a bonus factor. Generally, your efficiency losses resulting from hot weather are roughly equal to the reduction in power you get from being in a less sunny place, all other factors being equal.

      4) Monetary cost: Solar is expensive. No question. But isn't it worth it?

      5) Storage: Unlikely to be an issue. Aside from specialized case (read: nutcakes living off the grid or places where power isn't essential), solar is a peaking power resource that's used in conjunction with conventional generation technologies. At night? Pull your power from the grid. During the day? Send power back onto the grid (a.k.a. net metering). Much more efficient than trying to generate the power and store it.

      Further, the suggestion is definitely that this would be used in utility-scale applications, given the concentration of sun you need to have. So again, batteries are not really an issue, as any power sent out onto the grid is instanteously (or pretty damn close to it) consumed by a thousand hair dryers all running at once.
    • It's likely a much harder problem but if your grid is planet sized, and that isn't practical short of superconducting power cables or something like them, you may not need much power storage.


      The lightside could help power the darkside.

      Although unlikely any time soon, it would be a nice technology to have.

    • Re: (Score:3, Interesting)

      by Deslock ( 86955 )

      With solar, it all eventually comes back to storing the power, as they obviously don't operate in darkness. So how much would the batteries cost (initially, and in maintenance) to make this a viable power solution? How much wattage would you need to have enough "storage" for nighttime? Or more practically, for a few cloudy/rainy days in a row?

      There are several options other than chemical batteries. Pumped-storage hydroelectricity [wikipedia.org] is commonly used, but it's inefficient (for example, Northfield Mountain [wikipedia.org] only returns ~35% of the energy that's expended pumping the water uphill). Flywheels [wikipedia.org] are very promising. I read some interesting articles [www.mega.nu] in the 1990s about using them in electric cars, but that presents various challenges (cost, gyroscopic forces, what happens when a car crashes, etc). Even if we can't get that to work, is seems like they're a

    • Re: (Score:3, Informative)

      by Restil ( 31903 )
      1. Efficiency: This article talks about brightnesses of 100 suns. Well what about 1 sun? Or fraction of that (cloudyness)? Are these efficiencies realized then too? If not, does the technology still work at or near where that is?


      Probably about the same. The point is, you can ramp up the solar energy hitting the cell 1000 fold and still get 40% efficiency from it.

      Power cost: I've seen it said that many solar cells don't give back the energy required to manufacture them. By that I mean, acquiring the materi
  • suns (Score:5, Informative)

    by wizardforce ( 1005805 ) on Friday June 01, 2007 @06:52PM (#19358909) Journal

    The Spectrolab group experimented with concentrator multijunction solar cells that use high intensities of sunlight, the equivalent of 100s of suns, concentrated by lenses or mirrors. Significantly, the multijunction cells can also use the broad range of wavelengths in sunlight much more efficiently than single-junction cells.

    when the article talks about hundreds or thousands of suns, it means they used mirrors and lenses to concentrate the light that falls on a much larger area to then fall on the solar cells. this leads to the solar cells generating a lot more electrical power and thus makes it more economical to produce power from soalr energy as compared to not using mirrors or lenses to focus light onto the panals.
    • I'm kind of puzzled as to why few or no installed solar systems use mirrors or lenses to concentrate the sunlight. Mirrors are cheap and lightweight compared to solar panels so it should be a win compared to adding more panels. Fresnel lenses seem slightly less practical but still within the realm of possibility.

      And the mirrors don't have to be exactly parabolic since they aren't focusing on a point, you just need something that spreads a few more sq ft of sunlight across the panel, that would be great.

      Su
  • Solar is by far my favorite power source. But like every other power source, it is really just a byproduct of the actual energetic reaction. I think I can accurately say that solar power is second-hand nuclear power. Following this reasoning the other power sources may be seen as third-hand nuclear power.

    As another posted stated, even if you make the solar 100% efficient (wouldn't that be something!) you still have to store or transport it - since on average the sun is hitting half the Earth's surface at any given time (with much of that surface being water).

    I have high hopes for solar - but it always strikes me as strange that we already have this amazing technology of nuclear power - it's here now! We HAVE it!

    Plus, nuclear power can make a nuclear rocket! I don't know of any solar rockets yet.
    • Re: (Score:3, Informative)

      by AK Marc ( 707885 )
      I don't know of any solar rockets yet.

      http://en.wikipedia.org/wiki/Solar_sail [wikipedia.org]
    • by dbIII ( 701233 )
      It didn't take long for a nuclear troll to turn up so I should point out two things.

      First solar is usable in different situations - for example a nulcear powered pocket calculator is impractical. Second, due to poor investment in R&D and less demand for weapons materials a nuclear powered thermal power station is a more expensive way to boil water than it was in the 1970s when they could sell byproducts instead of relying on subsidies. There are several very promising proposals but they need more work

      • Not every one of us nuclear power advocate is a troll, first of all.

        Second, a nuclear powered calculator is perfectly plausible. First, power the grid with nuclear power. Then charge a calculator's batteries from the grid; the energy is still coming from nuclear power.

        There's a faction of society that's so adamantly anti-nuclear that it ignores all technological developments, and insists that nuclear power is just as reckless as it was back when people first started using it. It's just not true. Look at Fra
    • My concern is with the storage of waste. For example, this article [aftenposten.no] talks about a Russian dump of spent fuel rods from their nuclear submarines. They are leaking and if not taken care of soon, could cause a nasty disaster. FTA:

      A new report from Rosatom, the Russian government's highest nuclear authority, shows that there is a grave danger that the stockpile can explode. For Norway the consequences could exceed the fallout from the Chernobyl disaster in 1986, and no one knows how imminent the danger is - if i

      • Build a nuclear rocket, load it with some waste and shoot it at the Sun. Just make sure Nuclear Man doesn't find his way back or we're screwed.
      • by QuoteMstr ( 55051 ) <dan.colascione@gmail.com> on Friday June 01, 2007 @08:17PM (#19359641)
        Nuclear power production produces a lot less waste than coal mining alone does, and that's not even counting the radioactive dust [wikipedia.org] that coal power plants spew into the air.

        The Russians cut stupid corners in nuclear power. Not only did they use a graphite-moderated reactor at Chernobyl, but according to your linked article, they didn't glassify (or recycle) their nuclear waste. Furthermore, I doubt those rods have a high enough concentration of plutonium to actually explode. The article was a little light on the technical details.

        Also, waste is not "just so dangerous." By the very definition of half-life, the most intense radioactive waste is the stuff that breaks down the fastest. That's why we keep it in cooling ponds for a few years before doing something else with it. After the high-radioactive components have decayed, what's left has a very long half-life, which means that it has a low level of radioactivity.

        Besides, if at that level of radioactivty, you feel the need to manage waste for 10,000 years, how about managing our copper and gold mine tailings, which are killing our rivers? Or how about managing our toxic chemical waste, repairing underground gasoline tanks, cleaning up rivers that are so toxic that we can't eat fish out of them, and so on? What makes low-level nuclear waste more important than these more pressing problems?

        And as for accidents -- all industries have accidents. A chemical plant caught fire a few years ago and poisoned hundreds. But look at it this way: we only have two choices for energy for the next hundred years: coal or nuclear. Even if we do have a nuclear accident or two (which is highly unlikely, given the paranoia surrounding regulation of nuclear facilities), nuclear power would hurt and kill fewer people than coal will.

        Also, France uses nuclear power for 90% of its electrical needs. When's the last time you heard of a problem at a French power plant?
    • The problem is fuel. Our fission fuel is very limited, if we went 100% fusion we wouldn't be much better off then staying with oil and coal as far as how long we last is concerned. Fusion fuel is more abundant in our solar system, but even that is limited.

      The sun, on the other hand, will burn for another few billion years. It will burn most of its fuel (though not all) if we use what hits the earth of not. I see no reason to burn our limited nuclear fuel if we can avoid it. All domestic power can be me
      • Re: (Score:3, Insightful)

        by QuoteMstr ( 55051 )
        You are misinformed, sir. Fusion, if and when it eventually works, can be run using isotypes of hydrogen from seawater. I don't think we're going to be running out of that any time soon.

        As for fusion fuel -- it's an oft-repeated fallacy that we only have a tiny bit of that stuff. That view is terribly wrong. See this article [world-nuclear.org]. The gist of it is that nuclear fuel is limited only under these flawed assumptions:
        1. The only nuclear fuel mined will be the deposits that have so far been explored, and that are economi
    • We don't use nuclear because of all the loonies that hate it. That's right - everyone that opposes nuclear power is a tree-hugging crazy. Their arguements might sound well-reasoned but, no matter _what_ they say, there are no valid arguements against nuclear power - it truely _is_ the perfect power-source.

      Don't worry about the fact that we have to mine it. Don't worry that we need to build new reactors to process, use, and decommision it. Don't worry that all of this infrastructure will be useless when we r
      • by norton_I ( 64015 )
        Nuclear certainly has its share of problems, but even at the current state of the art it is probably better than coal and natural gas. I think that our current proven deposits of uranium could supply the entire US electricity demands for a couple of decades, and if U238 breeder reactors become economical, many times that long.

        It is also something that we can begin redeploying soon, while R&D on fusion and renewables continues. Nuclear is currently the only technology which shows an ability to take ove
    • by rs79 ( 71822 ) <hostmaster@open-rsc.org> on Friday June 01, 2007 @07:59PM (#19359497) Homepage
      Solar is great and all but what about the moon? Sometimes it's bright as hell out there but does lunar power get any press? Nooooooooo.
    • by jesser ( 77961 )
      Nuclear fission power is also "second-hand" fusion power. The uranium we use in fission plants comes from supernova explosions.
  • If I stick $1000 into a stock tracker. Would it beat the $1000 invested in this technology?

     
    • by wes33 ( 698200 )
      perhaps in the long run ... when markets collapse due to a failure to switch over to solar power and the few millions of us left are huddled in Northern Canada and Siberia
    • Re: (Score:3, Funny)

      According to my spam folder, solar technology from China is the next best thing to sliced bread. Buy early. Buy often. :P
  • Didn't we acheive this last year using indium-gallium-arsenide?
  • Dupe from December (Score:3, Informative)

    by Gertlex ( 722812 ) on Friday June 01, 2007 @07:03PM (#19358999)
    http://hardware.slashdot.org/article.pl?sid=06/12/ 06/027228 [slashdot.org]

    Ahh well. More publicity for Spectrolabs... :)
  • And I'm sure we're projected to see them in the magic next 5 years.
  • by e**(i pi)-1 ( 462311 ) on Friday June 01, 2007 @08:07PM (#19359567) Homepage Journal
    This is good news. I can not wait to have affordable solar cells to power a laptop. On board colar panels until now only can extend battery life for a laptop. There are foldable panels which generate enough power (26 watts) for a power friendly laptop: http://www.ascscientific.com/solar.html [ascscientific.com] For a laptop with solid state harddrive and power friendly CPU, onboard solar cells might soon be enough.
    • Re: (Score:3, Interesting)

      by Lumpy ( 12016 )
      If you shop surplus you can make a 60 watt solar panel that will not only run a laptop but charge it's batteries as well.

      I had one for a old outdated dell D600 laptop for the local ham radio group's Search and rescue group. we built it from $40.00 of surplus Yacht flexible solar cells. (3 units that were 3 feet long and 1 foot wide) they made 14.5 volts that simply powered a dell car charger/power supply for that laptop. It worked great just laying them out on a picnic table aiming straight up.

      Hard part i

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