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Power Science

New Record For Solar Cell Power Efficiency 351

Posted by kdawson
from the onward-to-50% dept.
mdsolar writes "Renewable Energy Access is reporting that a consortium led by researchers at the University of Delaware has achieved 42.8% efficiency with a silicon solar cell. The method uses lower concentration (factor of 20 magnification) than the previous record holder (40.7% efficiency) so that it may have a broader range of applications, since tolerances for pointing the device will be larger. They are now partnering with DuPont to build engineering and manufacturing prototypes. They expect to be in production in 2010. On a roof, such cells would require less than half the surface area to produce the same amount of power as today's standard solar panels, which have an efficiency of about 17%."
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New Record For Solar Cell Power Efficiency

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  • The real question.. (Score:2, Interesting)

    by Enderandrew (866215)
    Yes, but will it run Linux?

    Actually, while I'm glad they are making a more efficient solar panel, when will they make a cost-effecient solar panel for mass-adoption?
  • Smog (Score:5, Funny)

    by Rixel (131146) on Wednesday August 01, 2007 @04:28AM (#20068223)
    Hopefully, Solar Cell efficiency will keep ahead of smog cover in major cities.
  • Waiting (Score:5, Funny)

    by Cassius Corodes (1084513) on Wednesday August 01, 2007 @04:28AM (#20068229)
    Im waiting for them to reach above 100% efficiency before I'll buy
    • Re: (Score:3, Funny)

      by Hoi Polloi (522990)
      Great, I'm stuck with the old 1st generation -135% efficiency solar cells. They are gas powered.
  • a good grid tie system and these things will pay for themselves. I hope that panels of this efficiency are ready for public purchase when I am ready to be a homeowner. this is one of those things that makes economic and environmental sense and I hope it doesn't get stymied by people who are afraid to be "green" because they think it has to be more expensive.
    • Re:feasible (Score:5, Informative)

      by Calinous (985536) on Wednesday August 01, 2007 @04:36AM (#20068273)
      The most efficient use of solar power is the water heating system. Solar panels are a distant second for now - as they are very costly for the power they can produce (we assume your house needs heating or hot water). Depending on conditions, wind power might be a cheaper overall choice than solar panels.
              But in places like California, solar panels indeed pay for themselves
      • Re: (Score:2, Interesting)

        by evilviper (135110)

        The most efficient use of solar power is the water heating system.

        I'm not too sure about that. How about a PV panel powering a ground-source heat pump? I'm willing to bet that would give you more hot water than direct solar heating, at least in most climates.
        • Re: (Score:2, Informative)

          by Calinous (985536)
          It might be so - however, I don't know the costs of a ground-source heat pump. Did any digging recently? Also, you can get hot water at a higher efficiency than electricity from solar power, and the costs of installations are lower to boot. What a solar water heating system can't give you (but a PV panel/ground pump could easily) is cooling
          • Not too bad (Score:5, Informative)

            by Gr8Apes (679165) on Wednesday August 01, 2007 @07:23AM (#20069013)
            I looked into this recently. Installing a ground based heat pump instead of a regular air conditioner would have been around $6K (instead of $2K for the AC). Note that this was for an old style 12 SEER AC unit that's no longer available against a 25+ SEER heat pump (get added bonus of generating heat). AC units have almost doubled in cost, and now are about $4500 installed (new US regulations require higher SEER units).

            Why didn't I get the ground based system? Because when it's over 100 F and your main AC unit dies, I couldn't wait for the ground based unit installation taking over a week. I will plan for one at my next house though.
        • Re: (Score:3, Informative)

          by Smidge204 (605297)
          As per the summary, solar cells are 17% efficient. The efficiency of a heat pump will vary quite a bit depending on working temperatures, but the compressor motor will doubtfully be more than about 80% efficient (electrically). So overall, at best, 14% of the sunlight makes it into the hot water.

          Compare to direct solar heating, where damn near 100% of the energy you absorb gets transferred to the water. After all, the desired end product is heat, and it's trivial to convert 100% of any energy form into heat
          • by Smidge204 (605297)
            Forgot to factor in the COP.

            A decent heat pump will have a COP of around 3.5-4.0. So that 14% becomes 56%. Still losing to direct solar heat.
            =Smidge=
            • Re: (Score:3, Informative)

              by Dare nMc (468959)
              Not only is the theoretical maximum efficiency of blackbody air to water (with solar deflectors added in) max out to around 60%, so not much improvement needed to be equal. (since this 40%+ efficiency needs deflector as well)

              being in the process of doing a solar water heater myself, regardless the path you choose, you still have to run a pump, to even get close to a 14% solar direct to water heater efficiency.

              IE you can place the storage tank above the heater, and pull your fresh water through the heater,
        • by dbIII (701233)
          That all depends on where you are obviously. Boring deep holes is not cheap, but if you can get away with a shallow one it would be worth it.
      • Re:feasible (Score:5, Informative)

        by knarf (34928) on Wednesday August 01, 2007 @05:54AM (#20068599) Homepage
        That is why the two should be combined... Water-cooled Photovoltaic panels give the best of both worlds: cooler PV panels which are more effective PLUS warm/hot water for heating, hot water or - indirectly - cooling. The technology is out there. It is simple. It works. As to why is is not used that much yet? Good question.

        A search on 'water cooled pv' [google.com] gives some interesting documents about experiments done with this combination. Read them and then go and build something like that. My 2 puny 11 watt panels are somewhat to small for this application but anyone who has (plans for) panels on the roof AND a need of warm water does him/herself a disservice by not looking in to this IMnsHO...
      • Depending on conditions, wind power might be a cheaper overall choice than solar panels.

        The problem with wind power is that it's much more noticeable to your neighbors than solar. I live sort of at the top of a hill on 1.25 acres, and it's fairly windy. Theoretically, I could put of a few windmills and probably meet most (if not all) of my electricity needs, but my neighbors would definitely be complaining. The advantage of solar is that if you have good southern exposure and efficient panels, you can pr

      • by Lumpy (12016)
        They are costly if you buy new, if you get out there and buy some of the used ones for quite cheap. when I was living the Green Mode in my dome home I had an array of 6 8 foot panels from a solar power plant out west. they were cooked to a brown color from their collectors and only have 70% of their original capacity but for the money spent they worked great.

        Biggest problem is these new cells are essentially worthless on a home. collector systems means you have to have trackers for every bank of 2 or 3 pan
    • by evilviper (135110)

      I hope that panels of this efficiency are ready for public purchase when I am ready to be a homeowner.

      Why? You planning on putting a 50:1 solar concentrator mirror/lens in your yard?
      • Certainly would keep the neighboors/local dogs off your lawn......
      • Re:feasible (Score:5, Informative)

        by liquidpele (663430) on Wednesday August 01, 2007 @06:56AM (#20068871) Journal
        Joking aside, the best thing you can do for the energy usage of your home is ensure it is properly insulated and buy the quality efficient heating/air units. You can take it further by buying those new florescent light bulbs that are only around 14 watts, and having your computers hibernate during the day and night when you're not using them. You could see your power bill cut in half if you do all that.
  • hmmm. (Score:5, Informative)

    by apodyopsis (1048476) on Wednesday August 01, 2007 @04:28AM (#20068233)
    I'm interested in solar power as a means of lowering the fossil dependency - but there are other, better means of doing so. The CE manufacturers need to meet them half way and mandate more efficient devices that consume less power and bring back the humble ON/OFF switch that actually did turn off the power. Is it that hard to walk to the TV? And, of course, wind and tidal need to be followed up.

    The main problem is the general public. Everybody wants wind power (but not in their back yard) you have to actually change the law and rubbish collection to get them to recycle, and everybody needs to buy the latest and most powerful gadget on the market.

    Making a more efficient solar cell is an excellent step, but I'd be more interested in a more *cheap* one so they can be taken up on a mass scale.
    • Re: (Score:3, Interesting)

      Everybody wants wind power (but not in their back yard)

      That's one thing that I've never understood. I used to live about an hour's drive from a wind turbine and drove by it several times a day. I could never wait to drive by because I loved the sight. My new home is very windy and could benefit greatly from wind power. I simply cannot fathom the resistance to wind turbines.

      One thing I have always wondered though: given the fairly large surface area of the turbine blades, would it be possible to add a photosensitive material and pull a bit of power from the s

      • Re: (Score:3, Interesting)

        by Calinous (985536)
        The wind turbines convert some of the wind power in electricity, some of it goes in vortexes, and some goes into sound. A small wind turbine will spin at higher rpm in wind, and the noise might become unpleasant.
        As for solar power from blades' surface - the tower where the turbine is seated has more surface area than the blades, extra mass is not usually a problem, and you have a sun-facing side - the blades don't always have a sun-facing side (so you'll need to put panels on both side
      • Re:hmmm. (Score:4, Informative)

        by hcdejong (561314) <hobbes&xmsnet,nl> on Wednesday August 01, 2007 @05:36AM (#20068533)
        My parents live in an area that has lots of wind turbines. A few years ago, many of these were small, high-rpm turbines that were clearly audible from hundreds of meters away. Sitting in the back yard, you always had this droning noise in the background, this could be very annoying.
        Things did get better when they started replacing the small turbines with fewer, much larger ones. The turbines closest to their house were removed, and the new turbines ran at much lower rpm which means they produce less noise.

        As for sticking solar panels onto the turbine blades: this would make the blades heavier and less efficient. Also, you'd have to add slip rings on the root of each blade, and on the main shaft to transfer the power.
        Slip rings are expensive, heavy and they need maintenance, especially when you're transferring significant amounts of power through them.
      • Re: (Score:2, Funny)

        by tehcyder (746570)

        I simply cannot fathom the resistance to wind turbines.
        They're planning on one near where I live, and the most amusing objection/worry is that one of the blades might fly off and decapitate a swathe of children playing in their school a few hundred yeards away...
      • Re: (Score:3, Funny)

        by OldBus (596183)

        I simply cannot fathom the resistance to wind turbines
        It's probably drag and friction...
    • Re: (Score:3, Interesting)

      by pzs (857406)

      What really depresses me is seeing the general public in interview and their complacency and dismissiveness about global climate change. People's sense of entitlement is astonishing: "I work hard so I have the right to a low-cost long-haul flight," even if we've done without that "right" for thousands of years and those flights are ultimately destroying the planet.

      There is also the huge number of people who believe that the consensus of thousands of scientists on climate change is a "global conspiracy"

      • Re: (Score:2, Insightful)

        by lauwersw (727284)

        There's another idea about this gaining attention. Suppose people do care and start conserving energy. They pay less for their energy bill, so that means they own more money. What do they do with this money? Spend it on other things of course! So that means other people are earning more money, for example in other parts of the world that are currently using less energy. What will they do with this extra money? Yes, spend it and in that process use more energy than they would have before!

        Net result? 0

        Ma

        • Go to the brothel.

          Not everything that can be bought is bad for the environment.
          • Re: (Score:2, Funny)

            by Anonymous Coward
            The hooker herself can be inherently bad for the environment unless you find an off-the-grid vegan hooker. But by that point, she's so skinny and annoyingly opinionated that you really wouldn't want to touch her with a 20 foot pole. Besides, those emo frame glasses were made from petroleum.
          • Re:hmmm. (Score:5, Interesting)

            by pjabardo (977600) on Wednesday August 01, 2007 @07:46AM (#20069185)
            These are *VERY* wise words!

            Instead of making more money, people could work less. Instead of buying all sorts of shit, people could do much cleaner things such as talking, writing, riding a bike, going to a brothel, taking a walk, singing, playing a part on a play, painting, fighting (if not pushed too far it is not necessarily bad for some people...).

            It is way too simplistic to say that there is a law of nature that says we will end up using every resource available. We are supposed to be rational beings even if we often do stupid things. One of the things of being rational (or partly rational) is that we can choose what we do. We don't simply answer any call of the wild (even if there is such a thing).

            We are changing from a production society to a consumer one. We are becoming a bunch of morons that just sit and receive stuff. Not very different from the Eloi in H. G. Wells' The Time Machine. I don't think just consuming is satisfying enough. It is much easier (and faster) just to watch a movie than it is to tell a story and we end up watching 10 movies. Maybe a little boredom is good for creativity. It certainly is much cleaner than riding a car 100 km to do anything "new".
        • Re: (Score:3, Funny)

          by russ1337 (938915)

          They pay less for their energy bill, so that means they own more money....Spend it on other things and in that process use more energy than they would have before....Net result? 0
          I didn't realize my energy company was denying me spendable income with the intention of saving the planet. Here I thought they were just squeezing every cent from their customers for profits!
        • by Knutsi (959723)

          Maybe this is just a general law in nature: a species will use up all resources it can find. The only real solution would be a real clean source of energy. Your alternative would work too, but is way less attractive ;-)

          Not really, since there are several spices on top of various food chains, and they don't eat a whole lot more than their stomachs can hold. But your point reaches to the root of the problem however: the reason these creatures don't virally consume the world like we do, is that they are una

      • Re:hmmm. (Score:4, Insightful)

        by JaredOfEuropa (526365) on Wednesday August 01, 2007 @06:22AM (#20068689) Journal

        There is also the huge number of people who believe that the consensus of thousands of scientists on climate change is a "global conspiracy" and their fear that it may eventually mean, shock horror, more taxes.
        This believe is partly justified. The conspiracy isn't by the scientists, and isn't a global conspiracy either, but the climate scare has given the meddlers of any political stripe the perfect pretext to push their own agendas. The climate debate has been thoroughly politicised, at the expense of proper science. That does not mean that all conclusions are incorrect or made up, but very often peer reviews are sorely lacking, and many reports have had chapters and sections stricken in the final draft, because those sections could cast doubt on the severity or existence of human impact on the climate. In many cases scientists voicing such doubts have not been gainsaid, but fired from "scientific" institutions. Because a widespread doubt in our impact on the climate would spoil the party for the meddlesome politicians. The political stakes are huge, perhaps the largest of any issue in our history.

        Why are long term trends not taken into account in these reports, for example. It is rubbish to say that we cannot accurately predict climate that far into the future because our short-term predictions are not very good. After all, we cannot predict the little ups & downs in next month's weather, but we can predict that winter will follow summer and autumn, and we know what the trends are in each of those seasons. The long-term trends in global weather can be predicted as well.

        On a geological timescale, we are in high summer. Winter is coming, and in 10.000 years we'll be in an ice age. The start of the downward trend in average temperatures is imminent (which means anywhere between now and 1.000 years)... Perhaps that is why the IPCC report does not look any further than the year 2100, the scary hockeystick curve will flatten out after that year, and if you look even further it will drop. Our distant descendants (if any) may even be grateful for the extra CO2 we have released, since it might make the next ice age a little less severe.

        But with all that said, conservation and reducing our dependancy on a limited resource is a good thing. But I refuse to join in the mindless panic.
        • Re: (Score:3, Informative)

          by Retric (704075)
          1) Ice ages are somewhat random events so saying 10,000 years we will be in an ice age is silly it may have already happened or yet to start. Looking back several million years ices ages have no where near the consistency as the seasons. They don't all get as cold they don't last the same amount of time and they don't occur on a regular basis.

          2) Both sides are trying to muddy the waters. You don't hear "Everything will be fine" and you don't hear "We are all going to die" because there is some give and ta
        • Re:hmmm. (Score:4, Interesting)

          by Ambitwistor (1041236) on Wednesday August 01, 2007 @09:21AM (#20070365)

          That does not mean that all conclusions are incorrect or made up, but very often peer reviews are sorely lacking,
          The actual scientific literature published in journals is peer reviewed.

          and many reports have had chapters and sections stricken in the final draft, because those sections could cast doubt on the severity or existence of human impact on the climate. In many cases scientists voicing such doubts have not been gainsaid, but fired from "scientific" institutions.
          Please, give examples.

          And while you've raised the issue, shall we discuss political meddling in the opposite direction (cough EPA report cough)?

          Why are long term trends not taken into account in these reports, for example.
          They look at century time scales, but not longer, because (despite what you say) predictions are very hard to do for longer timescales, especially given the uncertainty in what humans will be doing in terms of atmospheric emissions and land use changes. Remember, climate physics is not the only input into climate prediction; you need projections of human activity as well. (See here [sciencemag.org].)

          Winter is coming, and in 10.000 years we'll be in an ice age. The start of the downward trend in average temperatures is imminent (which means anywhere between now and 1.000 years)...
          It is far from established when the next ice age cycle is going to start, and there are some who claim that due to patterns in orbital dynamics, the current interglacial could be exceptionally long (as long as 50,000 years). (See here [sciencemag.org].)

          Perhaps that is why the IPCC report does not look any further than the year 2100
          Perhaps it is, as I said, hard to project much more than a century or two in advance.

          the scary hockeystick curve will flatten out after that year, and if you look even further it will drop
          The current rate of warming far exceeds the natural rate of cooling during glaciation. That rate of warming will eventually level off, but it's not going to be outweighed by glaciation any time in the next few centuries.

          It is true that eventually we will enter a new ice age, regardless of global warming, but no one is "ignoring" this fact. It's just farther off into the future; right now, the warming is what we have to deal with. If warming is a problem, you can't just ignore it because someday it will be cooler.

          Our distant descendants (if any) may even be grateful for the extra CO2 we have released, since it might make the next ice age a little less severe.
          If that turns out to be the case, it's better to release the CO2 then, rather than now, when we don't need it. As we have seen already, it's far easier to raise the temperature quickly than it is to cool it, having to do with the ease in emitting CO2 as a byproduct of civilization and with the long residence time of CO2 in the atmosphere.
          • Re: (Score:3, Interesting)

            by JaredOfEuropa (526365)

            Please, give examples.

            Here's one [heartland.org]. The same happened with two scientists in a Dutch government-run climatological research institute. I'm sure you can find others, and I am also sure each of these examples can (and have) been countered by arguments of these scientists being fired for bad science or using "improper channels" to release their counter-claims.

            And while you've raised the issue, shall we discuss political meddling in the opposite direction (cough EPA report cough)?

            My point is that the entir

            • Re: (Score:3, Informative)

              by Ambitwistor (1041236)

              Here's one.

              A rather one-sided presentation, I might add, but since you concede that this has already been countered by pointing out Albright's poor science and publishing his own website calling his boss's work a "myth", I don't need to get into details.

              The same happened with two scientists in a Dutch government-run climatological research institute.

              Really? Who? The only one I've heard of is Tennekes, and as far as I've ever been able to determine, he was not fired — he simply retired. He certainly has said nothing to the contrary himself; all the claims about him being fired can be traced back to an of

        • Re: (Score:3, Insightful)

          by CommieLib (468883)
          Why are long term trends not taken into account in these reports, for example. It is rubbish to say that we cannot accurately predict climate that far into the future because our short-term predictions are not very good. After all, we cannot predict the little ups & downs in next month's weather, but we can predict that winter will follow summer and autumn, and we know what the trends are in each of those seasons. The long-term trends in global weather can be predicted as well.

          I've got to disagree with
      • Re: (Score:3, Insightful)

        I think you have a valid point but you need to look at why this happened.

        Among the general public, basically they've had the "global warming" concept beat into their heads, but they're watching the people doing it fly around the world in private jets and live in houses with 4K/month electricity bills.

        Among the geek skeptics, like myself, what I see is not science, it's religion. It's "we've solved this problem, we know it's happening, so NO MORE DEBATE ABOUT IT!!!!". That's not science. We're still debat
    • Re: (Score:2, Interesting)

      by monk.e.boy (1077985)

      My friend lives about a mile away from a small wind farm. I is very noisy, it sounds like cars on a freeway, but far too regular. Almost like a loud heart beat. And when the sun catches the blades you get a nice strobe effect which sends you fucking crazy after an hour or so.

      My friend is selling up.

      I can't wait, we never visit him any more. His house sucks.

      Wind farms are ok - so long as they aren't in your back yard. Solar and Nuke is the real future.

      monk.e.boy

      PS check my .sig for Open Source Flash Cha

    • Spot on. (Score:4, Informative)

      by ushering05401 (1086795) on Wednesday August 01, 2007 @06:01AM (#20068627) Journal
      "The CE manufacturers need to meet them half way and mandate more efficient devices that consume less power and bring back the humble ON/OFF switch that actually did turn off the power."

      I recently had a new lady move in with me... and she insisted on actually unplugging things like my stereo when we were not using it. I was skeptical about the benefits of this tactic to save electricity, but being a curious person I was willing to humor her.

      By unplugging all of my electronic devices (there are many of them) when not in use we saved around $30 U.S. a month. Where was all that energy going? Not sure.

      If you are the type of person that has electronics in every room give it a try for yourself. Even if you don't care about being 'green' you will likely see a difference in your energy bill. Either way you win.

      Regards.
      • Re:Spot on. (Score:5, Informative)

        by JaredOfEuropa (526365) on Wednesday August 01, 2007 @07:33AM (#20069085) Journal

        By unplugging all of my electronic devices (there are many of them) when not in use we saved around $30 U.S. a month. Where was all that energy going? Not sure.
        It goes to heat production, mostly. However I prefer a step forward rather than taking a step back by having to turn everything off. It is possible to make equipment have a minimal power consumption on standby, by only running a small circuit that looks for the "On" button being pressed on the device. A lot depend on how you power this circuit... a transformer is a notoriously bad way of doing it.
        Some equipment behaves nicely on standby. Use a Wattmeter to check how much your stuff actually consumes in standby mode; you'd be surprised how little some things consume when idle, and there is little use in unplugging these completely. You might also be surprised at the large amount of power drawn by plug in transformers (The "wall warts"). Removing these when you are not using them saves a lot.

        Another good way to save without sacrificing convenience, is to use a "master-slave" power block with your computer. I have a lot of inefficient transformer power supplies next to the computer, for printers, routers, LCDs, speakers, etc. I installed a "master-slave" system, that will automatically switch off all this rubbish when the computer is switched off. The power draw of this system when idle is minimal compared to those transformers, and you don't have to switch off every individual piece of equipment either,
    • I don't really see the problem with leaving devices on "standby". I'm not an electronics type, but it can't take that much power for a small IR receiver circuit to flick the power on for the main circuitry. The only problem with that is that governments allow people to sell goods where "standby" means "don't show a picture until they press a button". Other (PC-like) devices are starting to have extended startup times, and so standby is starting to mean "keep memory running, but don't show a picture...".
    • Re:hmmm. (Score:4, Interesting)

      by Sandbags (964742) on Wednesday August 01, 2007 @09:17AM (#20070307) Journal
      We don't even need a true power on off switch that has to be flipped manually. What we need is a remote power switch that cuts main power, and a small, rechargeable battery cell that can respond to the remote and re-activate main power. A tiny battery and a capacitor to have enough juice to throw a 2.5 volt magnetic switch would add about $1 in manufacturing costs to home theater devices, but save dozens per year in electric fees per home for "trickle" devices. All network devices should support Wake on LAN, but unfortunately, most don't (or do, but people don't know what that means or how to use it).

      Unfortunately, a lot of devices are always on, like DVRs, game stations with online access, and more. They do a lot of work at night updating databases, downloading new content, etc, and simply have to remain on. The fact that an XBox 360 doesn't spin down the graphic system power and down clock it's CPUs is a design issue we can change. An Apple TV box uses less than 20 watts when "asleep" and that included downloading content over wireless. Why can't the XBox and PS3 do that? They could even drop into an even lower power state when idle, spin down the HDD, and only "wake up" every 90 minutes or so to check for content without spinning the drive up again unless it needs to.

      Unfortunately, there are even more devices we can't really do anything about that are the real sappers in the house. The cable modem, wireless router/firewall, VoIP modem, second access point to cover downstairs, possibly an extra switch to add more than 4 wired devices (I have 7), and base station and answering machine for wireless phones. That's just the network. Now add the garage door opener, automatic sprinkler system, home alarm and smoke detectors (most run on house power and rechargeable batteries now), safety lights in your halls and bathrooms (night lights), and several clocks.

      I work for a computer systems manufacturer. We've got a meter (magnetic ring type thing) at the office that encircles a power line and displays the power being used by the device. We have it so we can document in our white papers the power consumption of our devices. I brought it home and played with it a few months ago when having a forum argument with another individual on this. My 27" tube TV used about 2 watts when sleeping. My 37" LCD used less than 1. My PS2 used no power (but the transformer was using 2 watts). My cable box used 12 watts when asleep, DVR used between 20 and 50 depending on what it was doing when asleep. What surprised me was the coffee pot was using 3 watts when off (it has a tiny built in clock). The 2 alarm clocks we have each use 5 watts. Adding up all my idle devices I was just over 220Watts in use! 10% of that was in scent plug-ins around the house and night lights, about 20% was in our cable boxes alone. 25% was in devices I can't turn off, like the garage opener, stove clock, built in microwave, etc. Another 20% was in my home theater equipment (amp, dvd, vcr, and TVs). There were some other random devices around as well, not including my network setup...

      After finding this out, I installed a "step on" power extension (like people use under the Christmas tree) in line between the wall and home theater, so I can press one switch at night to turn off all the device in the HT setup (except the DVR which has to stay pugged in all the time per the cable company or they'll void the warranty on the device). I threw out all the scent plug-ins in favor of passively diffused oils and popuri. I changed the few night lights we had out for LCD versions. I now have a programmable timer power strip in the computer room that I have 2 laptops, a small TV, a printer and a network switch hooked up to. Each night at 11:00PM the adapter cuts power to the laptops (which hibernate automatically after 15 minutes when on battery), my printers, the switch they're connected to, and the TV and cable box in there. My HTPC now uses sleep mode with Wake on Lan to save power and automatically shuts down and powers
  • by ihaveamo (989662) on Wednesday August 01, 2007 @04:29AM (#20068241)
    I'm working on a lunar cell at the moment... the other 50% of a day is totally untapped!!
    • by Calinous (985536)
      For when a starlight cell?
    • There was talk a while back of beaming microwave energy to earth from solar-power-collecting satellites, since they're outside the atmosphere, and in the sun at times when other spots on earth aren't. The moon might also fit into that satellite model, except that it's further away.
      • by mooingyak (720677)
        IIRC a satellite in a geosynch orbit is in sunlight for all but something like 10 minutes or so of a day.

        Can't find a reference at the moment though.
  • by suv4x4 (956391) on Wednesday August 01, 2007 @04:30AM (#20068245)
    On a roof, such cells would require less than half the surface area to produce the same amount of power as today's standard solar panels, which have an efficiency of about 17%.

    Let me guess: you'll leave how your roof empty to produce the same electricity, or take the whole roof to produce more than twice the electricity. Hard dilemma...

    At this point solar energy seems inevitable in our future. Not long from now we'll have more efficient electric motors and even more efficient solar cells, so that would make it a viable backup to a car battery charge and mean you can drive for days and days at long distance without recharging.

    The big money now will go to those people who manage to best make use of our existing infrastructure and our new technologies (stellar examples include Toyota's hybrids... imagine if that electric motor they use also has few solar panels to help it in the next models).
    • by Calinous (985536)
      Some cars already have a small solar panel in order to cope with the parasitic loads when the car is shut off (alarm, remote key, and other things). However, the solar power you could produce from the surface of a car is not enough to give you mobility. Look at the solar races, they reach maybe 100km/h during the day, using lots of solar panels, on a car that's worth hundred of thousands of dollars. And no air conditioning, it seems.
      • Re: (Score:2, Insightful)

        by suv4x4 (956391)
        However, the solar power you could produce from the surface of a car is not enough to give you mobility.

        They use conventional panels (17%). This one is 42%. Also I'm suggesting they won't run on pure solar, but support the electric motor in the same way the electric motor supports the diesel one in hybrids nowadays.

        It may drop your fuel consumption 15%, using "free" solar energy, still worth it.
        • by Calinous (985536) on Wednesday August 01, 2007 @05:27AM (#20068503)
          Assuming your car has 20 square meters of surface, all of it oriented towards the sun. In Ecuador. With 100% efficient solar panels.
                You can get at most 20 HP of power from that. In your real situation, with maybe 5 square meters of surface available in the morning, and lower solar power, and the 40% efficiency solar cells, you get 2HP (or 1.5KW). Does it help? A bit, yes. If your car can load itself all day with energy, and know when she will reach destination, she could bleed the electricity storage battery (and reload it later). This way, you could get 10 square meters of max power, 8 hours a day, and with perfect efficiency in rest (charge, discharge, motor) you get 80 HP hours - or two hours at 40HP. Good enough for a commute... but...
                Now, you could buy solar panels at $5000 per kW (and 20 pounds). Assuming double efficiency is treble the price - you need $15,000 per square meter, so you'll pay $150,000 for solar on your car. Is it worth to drop your fuel consumption 50%? Or completely?
          • Re: (Score:3, Informative)

            by TheRaven64 (641858)

            Seeing a car's power rated in terms of horsepower has always seemed somewhat excessive to me. For a long time, people used a single horse[1] to get around. They were quite slow for long distances, but could achieve something close to the legal speed limit for built-up areas. Since we're playing with absolutely ideal numbers, let's try another one; the car has zero mass.

            According to Wikipedia, the Sun produces approximately 1KW of energy per square metre. Your 20 square metre car then has a 20kW energy

          • by dbIII (701233)
            Think lightweight golf buggy instead of SUV - it's not quite so stupid then. The better answer is of course public transport giving you an economy of scale where you can use it - a low powered electric vehicle to get you a short distance to the train makes more sense than a long slow trip into town.
          • by Rocketship Underpant (804162) on Wednesday August 01, 2007 @07:57AM (#20069293)
            "Now, you could buy solar panels at $5000 per kW (and 20 pounds). Assuming double efficiency is treble the price - you need $15,000 per square meter, so you'll pay $150,000 for solar on your car. Is it worth to drop your fuel consumption 50%? Or completely?"

            This is the point where the central market planners jump in and shout that we should subsidize solar panels. But why does that solar panel cost $15,000 per square metre? Because of all the resources, energy, and labour consumed in producing it. Chances are those more than offset the gas you're not burning.

            When the manufacturer can make panels efficiently enough to be more affordable than gasoline, it'll be because they're finally less wasteful and polluting overall.

            A similar principle holds with recycling, by the way. In the instances where recycling actually saves on energy and raw materials, there is a cost savings as well, and the recycler will pay *you* for your bottles and cans. If the government has to make you do it, it's because the process is not cost-effective overall, and more waste is taking place in the recycling process than the recycling itself saves.

        • Re: (Score:3, Insightful)

          by tekrat (242117)
          So, run this by me again;...

          Consider that, aside from police cars and taxis, most cars spend most of the time PARKED, either in a parking lot at work, or a driveway at home. The average car's lifespan is mostly spent at rest, with about a 1/2 hr drive to work and a 1/2 hr drive home.

          Why is it NOT prudent to build a solar panel into the roof and/or engine hood to help recharge the batteries while the damn thing spends 8 hrs per day parked in the sunshine?

          Hell, if we could take the heat that builds up inside
    • "At this point solar energy seems inevitable in our future. Not long from now we'll have more efficient electric motors and even more efficient solar cells, so that would make it a viable backup to a car battery charge and mean you can drive for days and days at long distance without recharging."

      It was more than 15 years ago when similar comments were being tossed about, as the Japanese Govt. began pumping money into solar as a technology. The prediction then was that within the decade, solar energy woul
    • by inflex (123318)

      > Not long from now we'll have more efficient electric motors

      Currently, brushless (3 phase) digitally controlled motors are already in the high 95~98%+ level at 'optimal' RPM, dropping into the 80% area when running at less than optimal RPM. Incremental gains from improved stator materials, smoother bearings/sleeves, more efficient drivers (MOSFET/IGBT) will come but for the most part you're already looking at technology that is extremely efficient.

      Some things I'd really like to see are;

      1. a good

  • I'm not a solar panel expert, but the statement

    "On a roof, such cells would require less than half the surface area to produce the same amount of power as today's standard solar panels, which have an efficiency of about 17%."

    purely based on efficiency is dangerous. A lot of solar cells require a certain minimal light threshold before they start producing energy, and for reallife application, a lower threshold matters more than a few percent more of peak efficiency.

    IOW efficiency is a function of among other
  • How much power? (Score:4, Interesting)

    by DoofusOfDeath (636671) on Wednesday August 01, 2007 @04:32AM (#20068261)

    On a roof, such cells would require less than half the surface area to produce the same amount of power as today's standard solar panels, which have an efficiency of about 17%."

    OK, but how much of a typical house's power would that supply? (I realize this depends on location and time of year.)

    Or how many panels would it take to give you a daily, full recharge of a plug-in hybrid in, say, Los Angeles? (Imagine that that would do for LA's smog.)

    • Re:How much power? (Score:4, Informative)

      by Calinous (985536) on Wednesday August 01, 2007 @05:00AM (#20068377)
      Peak solar power is around 750W per square meter of installation. With those new panels, you could get - let's say - 1000W per 4 square meters (40 square feet).
            Assuming you are going at work using 10kW (14 HP) average for two hours (both ways), and assuming 6 hours a day peak power, and your losses are zero, you need less than 15 square meters (160 square feet).
            Now, if you add 50% losses in the recharge system (car and house), you need to double that - 30 square meters, or some 300+ square feet of solar installation, inclined to an angle equal to your location's latitude (equator- flat roof top, Alaska - sharp roof)
      • Instead of putting solar cells on the roof of a car, why not cover the south side of the garage roof with them, sell it to the electric utility during peak rates, and recharge an electric hybrid at night (when the utility rates are cheaper)? Seems like that would be a better way to power an electric vehicle, and generate a little cash to improve the household budget as well.

        In my case, I have at least 400 sq ft of south-facing garage roof (at a 12-12 pitch) and about twice as much on the house. Last month
    • by ari_j (90255)
      What bothers me is that the blurb (RTFA? never!) doesn't tell us exactly how loose the tolerances for aiming this one are. I don't care that it's more efficient if it requires me to put my house on a turntable and add a tilting roof.
  • It seems the cells uses three different solar receptors (low, mid and high energy light), and doesn't need precise tracking devices.
    A satellite-based solar panel could easily have the solar tracking device - however, tracking devices are expensive, could be affected by strong winds (for big installations), and use some power by themselves. Such a kit could bring higher efficiency in stationary panels, or (as suggested in article) could be used by the army as recharge packs for and inst
  • by Shivetya (243324) on Wednesday August 01, 2007 @04:38AM (#20068281) Homepage Journal
    that renewable sources of energy are a good thing.

    why?

    because my HOA (home owners association) does not permit them. As such it would take State or local laws to override the HOA; because in many States the HOA rules have strong legal backing at the State level.

    This is akin to the problems satellite TV faced in many locales. There were numerous ordinaces, both at the HOA and local level which blocked satellite dishes. Even the small ones we are accustomed to today were blocked. It took a Federal Law to end that restriction. Unfortunately its going to take another such law to allow many of us to use renewable energy. Hell, I cannot even get rain barrels approved even though they would not be visible from the street.
    • by Alioth (221270)
      If it's not visible from the street...well, it's better to ask for forgiveness than for permission. Just install the rain barrels, chances are no one will notice them.
  • by Anonymous Coward on Wednesday August 01, 2007 @04:46AM (#20068321)
    ...than price per watt. We got plenty of space we can cover with solar cells so it's not important that they are extremely efficient, just cheap enough so it doesn't cost much to cover large areas.
    • Actually, price per watt is probably just below price per lifetime watt-hour. If it costs more to buy than the cells will produce, it's just an off-grid luxury item.
  • by fringd (120235) on Wednesday August 01, 2007 @04:46AM (#20068325) Homepage
    The real problem with solar power is not getting more watts per square inch; it's getting more watts per dollar. From what I hear, high grade silicon is prohibitively expensive. It takes more than 3 years to pay back your monetary investment. This information is probably based upon old panels though.

    These new panels may produce twice the energy, but is there any chance that they cost less than twice the dollars? What is the limiting factor in solar panel costs?

    I've heard that some people are working on polymer solar panels, this would seem to deal with the dependence on expensive silicon...
    • About payback times (Score:3, Informative)

      by Anonymous Coward
      It probably takes a lot more than three years to pay back the investment. A three year payback would be astounding. If that were the case, you could shut down all the existing power plants and run the country just on solar. OK, that's a bit exagerated because solar doesn't make power all the time. Even so, a three year payback would see a dramatic increase in solar use.

      The calculation that produces a three year period says that you start saving money after three years. It assumes that you borrow money
      • by olman (127310)
        The point of the link is that, even if it takes a long time to pay for the system, you can still save money by going solar.

        Assuming maintenance free operation for 20 years, of course. No panel breakage or degradation, equipment failures, need to replace batteries..
    • by dwandy (907337) on Wednesday August 01, 2007 @05:51AM (#20068577) Homepage Journal

      It takes more than 3 years to pay back your monetary investment.
      "Three years" should not be a 'too long' perdiod to re-coup your investment.
      • That's less than 4% of an average lifetime.
      • I'd take an investment that was guaranteed to pay back 100% every three years.

      I don't see energy getting any cheaper on this planet, and I don't see energy consumption decreasing.

      The problem is it's not just the solar panels: it's the batteries and other infrastructure (and then maintenance!), and the last time I looked at it, it was closer to 20-yrs to pay back a whole system, and the system had a 20-yr life expectancy. That's break-even assuming it makes it to life expectancy.

      What I am interested in is directly attaching an AC unit to a solar panel. Where I live it's generally only hot when it's sunny, so the AC would run for free.
      Since the AC is one of the most expensive things to run it's win-win-win-win:

      • I can run it guilt-free
      • It runs whenever it's hot
      • I don't need the other infrastructure
      • I will still pay for the panel in a relatively short time.
      • The problem is it's not just the solar panels: it's the batteries and other infrastructure (and then maintenance!), and the last time I looked at it, it was closer to 20-yrs to pay back a whole system, and the system had a 20-yr life expectancy. That's break-even assuming it makes it to life expectancy.

        Exactly. Also, the life expectancy of a solar roof is even worse if you live in a high-risk area, such as Florida. How well does a solar roof hold up to a hurricane? How much will it cost to repair?

        How

        • by Thing 1 (178996)

          It's already common for swimming pools to be heated with solar panels. This is a nice new step.

          Rude awakening when we moved to Florida: "solar heated pool" means "it's heated by the sun." :(

      • Re: (Score:3, Insightful)

        by dbIII (701233)
        If you are running AC then solar thermal in one of many forms is a better idea - use that heat to move heat around instead of making electricity and turn it back into heat to move heat around. Then you use your panel for your electronic stuff runing on DC - suddenly you don't need a very big panel anymore.
  • ...cover the front of solar cell with deep, open, honeycomb-shaped, reflective walls (e.g. Aluminum or silver) grid? That would effectively act as a light trap, making solar panel more "absolutely black body"-like. Or, even better, make open "boxes" with walls covered in solar cells. Photon should have very little chance to escape after multiple reflections...
    • by Calinous (985536)
      Some of the energy is "lost" as light reflection, while some is lost as heat. Anyway, once a photon starts to go away from the cell, the reflective walls will direct it outwards
    • Re: (Score:2, Insightful)

      by zqwerty (686798)
      Its 20 years since I looked into solar cells in my engineering job, but the figure quoted above must be close to theoretical maximum because solar cells amount to a forward biased diode and can never get to 50% efficiency, they also have poor temperature performance which falls off rapidly as they get hotter, so enclosing them and reflecting more sunlight onto them is exactly the wrong thing to do, they run most efficiently when cool. As said in this thread the big problem is cost and having to store the e
  • To me spending $3 per gallon of gas. Now maybe they can manufacture these solar cells cheaper than the power company can make them. Personally, I think it is only a matter of time until we see either solar cells or a solar collecting stirling engines on each home to offset peak power usage...
  • by Linker3000 (626634) on Wednesday August 01, 2007 @06:02AM (#20068629) Journal
    The development of solar power will go a good way to lowering our dependency on fossil fuels, but to be practical we need to deploy the cells in a massive scale - I'm thinking thousands of square miles of solar farms - so what we really need is a relatively flat landscape in a location with significant sunshine levels. It would also be ideal if the region could provide the raw materials for the manufacture of the cells to save in transportation costs, but to be perfect the region would also have an abundant supply of fossil fuels to power the manufacturing plants until such time as construction was complete.

    In summary, the ideal location would have:

    Sun
    Sand
    Oil

    You see what I did there!?
  • fail (Score:4, Funny)

    by jovius (974690) on Wednesday August 01, 2007 @06:28AM (#20068705)
    Yes, this is great, but solar power will eventually fail completely, and there are no guarantees for long-term investments beyond five billion years from now.
  • by Anonymous Coward on Wednesday August 01, 2007 @06:41AM (#20068765)
    What matters to me: Do those new cells finally "produce" more energy during their life than they required during manufactoring?
    • Re: (Score:3, Insightful)

      What matters to me: Do those new cells finally "produce" more energy during their life than they required during manufactoring?

      What do you mean "finally"? They always have, though nowadays they recover the energy used in their production much faster than they used to. A few years to recovery is typical, and you really have to be trying to make it more than a decade. By contrast, the solar panels themselves are waranteed for 20+ years and thought to have useful lifetimes of 30+ years.

  • by Doc Ruby (173196) on Wednesday August 01, 2007 @07:02AM (#20068893) Homepage Journal
    Concentration of a larger solar input area onto a smaller solar cell is nearly always better than straight 1:1 reception. The efficiency goes up with these materials, which of course is good.

    But also the concentrators are a lot cheaper than the cells. The concentrator is usually a cheap (compared to the cell) lens or mirror. So a 20x concentrator gets 20x the input energy, but for a much lower cost than 20 cells. And that cell is operating at higher efficiency, on 20x the input. So a $10 cell fed by 20 $5 concentrators costs only $110 instead of $200. 5% more efficiency in the cell is applied to all 20 concentrators, not just the 1 cell, for 200% efficiency. So it's double the efficiency at 55% the price, or over 3.6x the $:energy efficiency. In reality, the concentrators are better than 5x cheaper, and the efficiency gains can go higher than 5% greater.

    And then there's all the savings from cheaper replacement concentrators, which could even last longer than the cells (though the cells typically last >30 years), and dropping all the other HW from the 19 (or however many) extra cells in favor of "dumb" concentrators. In fact, since concentrators are so cheap, the cells might not require HW to track the Sun for maximum absorbtion, but just array the concentrators in an arc (or bubble) that always leaves an array of concentrators facing the Sun (and the rest off-axis), without consuming energy to move. Or extra parts, or computing, and saving all the maintenance costs, too.

    So the more concentration, the better. After all, that's how the engineers thought up this stuff.
  • Is why every building/house isn't required to have at least one solar panel on the roof. I could care less about their efficiency, or the ability to run my whole house on them, but the relative low cost and huge amount of energy would benefit everyone. Give people a tax break like they do for weatherproofing your home and make it mandatory.

    Full systems to run a home only cost $10k-15k, and single fairly large panels and the needed wiring are ~$1k without batteries or other complexity.

    It would also bring dow
  • I wish at least someone would run the numbers on these things once and for all.
    • Solar collectors are expensive.
    • You need a mirror, a support, maybe a steering system, periodic cleaning and maintenance.
    • If the support is going to last more than one year, it needs to be rather sturdy in order to survive wind, rain, maybe snow and hail.
    • So we're talking an installed cost of lets say $500 per square meter, more if it's steerable. Plus yearly cleaning and maintenance.
    • Now a square meter of sunlight is about 1
  • I remember reading that there was a research program trying to make solar cells work with UV as well as visible spectrum light. That way, you can still make use of the UV part of the spectrum even on cloudy days.

    Speaking of solar power, have we yet come up with a way of capturing ambient heat and doing something with it? When I look at my car in the midday sun, I'm reminded of Texas prison movies with prisoners getting put in "the box." Sheesh! Can't somebody do something with all that heat just sitting aro
  • This is great news, but I am a little curious about the cost of these things... The biggest barrier to solar cells right now is cost, not efficiency. This new cell is about twice as efficient as your typical single layer panel but how much more expensive is it? 50% more expensive? Twice as expensive? 10 times more expensive? This thing has several layers and optics to separate the light... apparently in a much tighter package than similar devices in the past, but still complex and big relative to your sta
  • by ilovethesun (1135837) on Wednesday August 01, 2007 @08:36AM (#20069733)
    Hi,

    I will try to put a summary to the interested folks around:

    A photovoltaic system is composed today by:
    - Module
    - Inverter DC/AC
    - Mounting system
    - Cabling
    - Measuring/Protection electrical stuff

    Most of the cost today is the module. Systems go (net) for 4-5$/Watt.
    More efficient cells (and modules) mean less installation costs. For the future, it will be important since cell and module prices will go down.

    Today, in California, if you take a system lifetime of 25 years, the kWh equivalent "price" is about 25-30cent.

    System price decrease is expected to be 5-10% yearly for the next 5-10 years at least. This means that very soon the PV power will be cheaper than the one sold by the utility.

    PV systems are perfect for distributed energy: a centralized power plant is not really cheaper or more efficient than a 5kW roof installation. And the energy transport kills the small margin that you had in favour of the big thing. That is why most utilities are not hot about PV: it is against their business model.

    For the moment, it is not cheap to get "disconnected" from the grid. Therefore, a mix of PV and other electricity is necessary. PV has a nice peak at max. consumption peak. However, the evening consumption must be covered otherwise. Wind, biomass, ocean waves, geothermal, whatever.

    PV in order to charge e-cars is OK today already. A car that uses 10 liter to do 100km, at a 20kW mean power, is using 20kWh energy for 10 liter gas, at 1$/liter it would be 50 cent/kWh. Make the calculation with your local gas price/gallon and you see that, even today, it is competitive. And cleaner. Only e-cars are not yet developed/deployed as they need to be.

    About Solar-thermal energy for cold- it works for mid-big sized equipments, it is cheaper and especially more reliable than electricity... PV supporting electrical AC is still a bit more expensive but both run a nice race.

    Ah, the typical guy asks about energy payback times: depending on technology, after 1-4 years your system has produced the energy needed to make it. Longer times belong to PV prehistory and to right-wing-thinktank analysis.

    Cheers!
  • Wow, how innaccurate (Score:3, Informative)

    by Maury Markowitz (452832) on Wednesday August 01, 2007 @08:46AM (#20069881) Homepage
    > On a roof, such cells would require less than half the surface area to
    > produce the same amount of power as today's standard solar panels,
    > which have an efficiency of about 17%."

    The article being quoted clearly states that these cells require concentrated sunlight -- this is true of all thin-film high-TSE cells. So basically you can't mount them on the roof, you'll get no power at all.

    Further, most solar panels get about 11% efficiency. There are ones that get into the 15-17% range, but these are much more expensive and see considerably less use as a result.

    These new cells will be very useful for large-scale energy developments, like large solar farms in the desert. They are completely useless for rooftop deployment.

    Maury
    • In fact, roof top concentrators look quite practical: http://www.technologyreview.com/Energy/18718/ [technologyreview.com]. I wish the original article had given a diagram of how their system is laidout, but it definitely mentioned rooftop use.

      You won't be all that competitive is you are producing 11% efficient solar today. I think perhaps you are thinking that most solar panels already sold have a lower efficiency. One company is selling at $3.00/watt for lower efficency panels as compared with $4.20/watt for most. You hav
  • High tech one offs (Score:3, Insightful)

    by Danathar (267989) on Wednesday August 01, 2007 @10:43AM (#20071863) Journal
    I think most people would be surprised what can be created with technology when you only have to make a few of them. It's the mass manufacture of "scifi" like devices that is HARD.

    If I wanted to create super sci-fi stuff for my spy that's not so hard, custom made stuff with lots of money behind it can do amazing things.

    I'm really hoping that their method is mass manufacturable.

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