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New Solar Cell Sets Record For Energy Efficiency 165

Posted by samzenpus
from the getting-closer dept.
Lucas123 writes "After three years of work, German and French researchers have achieved a new world record on converting sunlight to energy through a photovoltaic cell, achieving a 44.7% rate of efficiency, which was measured at a concentration of 297 suns. The efficiency rating means the solar cell collects 44.7% of the sun's spectrum's energy, from ultraviolet to the infrared spectrum, which is converted into electrical energy. The team of researchers said the technology places them on the path to achieving their roadmap of 50% efficiency in solar energy conversion."
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New Solar Cell Sets Record For Energy Efficiency

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  • Thats better than the 25-30% gasoline efficiency. So it sounds good to me! http://en.wikipedia.org/wiki/Engine_efficiency [wikipedia.org]
    • by InvalidError (771317) on Thursday September 26, 2013 @09:44PM (#44966799)

      Not much point in comparing the efficiency of an energy source with the efficiency of an energy sink; they're at the opposite ends of the energy cycle.

      Unless you can use your solar-electric power immediately, you also need to add a whole conversion system for storage and discharge which can be quite lossy if you choose electrolysis for energy storage due to much higher energy density than batteries.

      To make a fair comparison, you would need to pit two options with similar energy cycle against each other. Something like solar-hydrogen vs solar-biodiesel or solar-ethanol. Growing algae and converting it to biodiesel or ethanol to keep internal combustion engines running might be more efficient overall than electrolysis to produce hydrogen before converting that back to electricity to drive electric motors. Ethanol and biodiesel also have the benefits of well-established distribution channels while high-pressure hydrogen is still scary for many people.

      I'm not including plug-in electric since everyone I know seem to be highly skeptical of their operating range and seriously worried about battery replacement costs that can quickly wipe out any fuel savings.

      • by AmiMoJo (196126) *

        Unless you can use your solar-electric power immediately, you also need to add a whole conversion system for storage and discharge

        Or, sell it for a tidy profit. If needs be you can buy it back later at night when electricity is cheaper due to less demand.

      • by rcw-home (122017)
        It is, however, worth comparing a photovoltaic conversion of solar to grid power to a heat engine conversion of solar to grid power [wikipedia.org], particularly when the latter currently holds the world record for efficiency for that particular conversion.
  • by Maxo-Texas (864189) on Thursday September 26, 2013 @07:03PM (#44965785)

    At cleantechnica site you can see a priced drop of $76/w to under $.74 a watt in only (sorta wish it was .76 a watt for neatness sake, dontcha?)

    http://cleantechnica.com/2013/05/24/solar-powers-massive-price-drop-graph/ [cleantechnica.com]

    You can also see a similar exponential but reverse growth curve off a link from that page.

    Elsewhere, I saw solar was projected to generate more energy than the U.S. currently generates by 2050-- and to quintuple from there by 2100.

    ---

    Loved "Mystery Men". On my top 100 list.

    • by Virtucon (127420)

      I'm still waiting for a Solar powered Fraculator.

    • by Firethorn (177587) on Thursday September 26, 2013 @07:29PM (#44965985) Homepage Journal

      As usual, an XKCD [xkcd.com] comic applies...

      You always have to be careful about extrapolation. What looks like exponential growth is unlikely to stay that way as further order effects come into play.

      • by khallow (566160)
        He's extrapolating from more than two data points and there's a crude model that explains what's going on. Sure, I don't see anything staying exponential forever, but why think that the trend is going to break right now rather than 50 years from now?
        • by Firethorn (177587)

          I'm not saying it's going to break now. I think it'd break(IE level off) before solar alone outstrips all current power generation in the USA.

          Also, it takes more than 2 data points to even extrapolate for exponential growth.

          • by khallow (566160)

            Also, it takes more than 2 data points to even extrapolate for exponential growth.

            Then it's a good thing there's more than two data points there. But let's consider your assertion. One can take the log of the value part of the two data points (which are value-time pairs). Your XKCD link already showed the scientifically dubious but very feasible approach of extrapolating a line from two data points. Exponentiating back to the original values yields an exponential curve.

            Hence, you just extrapolated an exponential curve from two points.

            • If the underlying equation is exp(ct), c=arbitrary, t=time, 2 points suffice to determine a (real-valued, unique) c.

              If the underlying equation is b+exp(ct), 3 points are needed to determine b and c.

            • by Firethorn (177587)

              Then it's a good thing there's more than two data points there.

              Yeah, misread your original post; rereading later I saw the deal. My original point was more along the lines that if you look from the initial cell culture bacterial growth in a petri dish will be a very clear exponential curve - right up to the limits of the dish. I don't think that solar adoption is going to slow anytime soon(other than regular already known swings), it's just that taking it to 2050 and 'more power than the USA currently uses' is a bit far to be extrapolating.

              Solar power is not suited f

      • Here...
        Give it a look and let us know what you think...

        http://solarfocus.blogspot.com/2009/02/solar-goes-supernova.html [blogspot.com]

    • What happened in the early 90's that made the price go back up? Is that just noise in the graph? Subsidies dropped?

  • by NoNonAlphaCharsHere (2201864) on Thursday September 26, 2013 @07:03PM (#44965791)
    Sure, the Germans get better solar efficiency, they get a lot more sun.
    • Re:Well of course (Score:5, Interesting)

      by SternisheFan (2529412) on Thursday September 26, 2013 @08:18PM (#44966269)
      Actually, no they don't. I googled "How much sunlight does Germany get" and after disregarding Fox's disinformation links, I found this:

      Germany: Your Unlikely World Leader in Solar Power

      germany solar leaderThe average day in Germany is cloudy. In fact, Germans see an average of just over 1500 hours of sunshine per year, a bit less than 64 days worth of sunlight. Needless to say, Germany would be one of the last countries you’d expect to be the overwhelming leader in solar energy production. Yet here it is. Germany alone has half of the world’s solar installations and is the third-largest producer of solar cells. Q-Cells, a German company, recently pulled ahead of Sharp as the world’s largest maker of photovoltaic cells. So how did they do it? How could a dreary country like Germany singlehandedly conquer the solar industry?

      To find out, one need look no further than the German government’s aggressive renewable energy incentives. In 2000 the Renewable Energy Sources Act was passed, requiring the country’s utility companies to purchase electricity from solar start-ups at rates higher than retail value. Commonly known as feed-in tariffs, these subsidies made it easy for new solar companies to turn a profit. In fact, their profits were pretty much locked in, and companies raced to get started. That’s how in just four years Germany was already responsible for half of solar electricity generated worldwide.

      Now, eight years later the country is still going strong. The progressive law is a broad measure attempting to reduce carbon emissions. The goal is to derive a quarter of its power from renewable sources by 2020. They are already ahead of the 12.5%-by-2010 benchmark set by the European Union. Germany already stands tall with 14.2% of its electricity coming from renewable sources.

      And the effect of Germany’s solar leadership has resonated globally. Spain, France, Italy, and Greece have installed similar incentive plans. And U.S. states, led by California, have instituted German-inspired incentives such as net metering.

      Link: http://solar.calfinder.com/blog/solar-information/germany-your-unlikely-world-leader-in-solar-power/ [calfinder.com]

      • by NoNonAlphaCharsHere (2201864) on Thursday September 26, 2013 @08:31PM (#44966355)
        Thank you, Sheldon; that was interesting.
        • Thank you, Sheldon; that was interesting.

          Your welcome, NoNon.

          P.S. My mother called me 'Sheldon' once.

          But just once.

      • by Trogre (513942)

        That solar data just goes to further illustrate that if the Gulf Stream were to ever shift or cease, Europe would be utterly screwed.

        • Nope, It would save a fortune on bridges. We would be able to ride across the ice.
        • That solar data just goes to further illustrate that if the Gulf Stream were to ever shift or cease, Europe would be utterly screwed.
          In what respect?

          If the gulf stream changes we likely get more sun ...

          The gulf stream mainly only influences temperatures in winter, I would say in summer its effect is rather low (regarding warmth) and causing more clouds.

      • Re:Well of course (Score:5, Informative)

        by Solandri (704621) on Thursday September 26, 2013 @11:54PM (#44967479)
        Capacity factor for PV solar in the U.S. [epis.com] is about 0.145. That is, if you plop down a 1000 Watt panel angled at your latitude, and measure its power generation for a year, it'll average out to 145 Watts. It incorporates everything - weather, angle of the sun, night, etc. Across the country, it ranges from about 0.185 in the desert southwest, to 0.11 in New England.

        From the Wikipedia article [wikipedia.org], in 2012 Germany had 32.6 GW of installed PV solar capacity, and it generated 28 GWh of electricity. A year is 8766 hours, so that's an average generation rate of 28000 GWh / 8766 h = 3.19 GW. So their PV solar capacity factor is 0.098 (Numerous hits on Google reporting instantaneous generation and generation over 24 hours notwithstanding - those don't matter, only the long-term cyclical average does, a natural cycle of seasons being one year.)

        Basically, Germany is a terrible place to install PV solar [wikimedia.org]. The only reason it's viable there is because their green energy initiatives have driven up the cost of their electricity [wikipedia.org] to about $0.34/kWh (vs about $0.20/kWh for France and the UK). Numerous studies put the cost of electricity from PV solar [wikipedia.org] at about 2x-5x the cost from other sources. So normally it wouldn't be cost-effective. But if you raise electricity prices to 3x what it is in the U.S., suddenly PV solar becomes financially viable.
        • You simplify to much.

          Meanwhile a nice placed solar plant would be cost effective even without the granted feed in tariffs.

          This is due to the fact that you can sell your energy at the spot market and the price for energy peaks there regularly far above the feed in tariffs.

          Capacity factors ... an invention by wikipedia ... and some guys who gives talks in TV shows ;D

          No one in the energy business uses that term, it is completely useless.

          • You simplify to much.

            Meanwhile a nice placed solar plant would be cost effective even without the granted feed in tariffs.

            This is due to the fact that you can sell your energy at the spot market and the price for energy peaks there regularly far above the feed in tariffs.

            Only because government regulations mandate renewable power always be purchased, often times leading to negative electricity prices (i.e. power company pays you to waste electricity - nice perverse incentive!). This is basically the same as a tariff - a law meant to protect a particular industry even though its consequences on the whole are a net loss.

            Capacity factors ... an invention by wikipedia ... and some guys who gives talks in TV shows ;D

            No one in the energy business uses that term, it is completely useless.

            I hope that was sarcasm, otherwise you're an idiot.

          • > No one in the energy business uses that term, it is completely useless.

            I'm in the energy business, and we use it all the time. So does everyone else, like

            The EIA: http://www.eia.gov/tools/faqs/what-capacity-factor
            The NRC: http://www.nrc.gov/reading-rm/basic-ref/glossary/capacity-factor-net.html
            NREL: http://www.nrel.gov/analysis/tech_cap_factor.html
            The RMI: http://www.rmi.org/rmi/Capacity%20Factor
            The EPA: http://www.epa.gov/airtransport/pdfs/TSD_capacity_factors_analysis_for_new_units_7-6-10.pdf

            along wi

        • by AmiMoJo (196126) *

          It's only terrible if you ignore the external costs of other production methods. Once you factor those in German solar PV looks pretty good against nuclear and coal, although not nearly as good as wind.

        • $0.34/kwh is already what we pay ConEdison in NYC. So we're already at break-even here. ConEdison has raised rates double-digit percentages every year for the past 10 years. The price per watt solar panel installation has fallen to $2, and that's dropping quickly. With those two trends we don't need any government intervention to produce a sea-change from centralized- to distributed power generation in this country in the next decade.

          There is also the not inconsiderable effect Hurricane Sandy had on hea

        • > Numerous studies put the cost of electricity from PV solar [wikipedia.org

          As one of the people that wrote the article you're quoting, perhaps I'll jump in here

          > at about 2x-5x the cost from other sources

          The price of power from any source is dominated by three things, the CAPEX or how much you payed to build it, the OPEX (or O&M) which includes fuel costs and maintenance, and the duty cycle, what percentage of the time it runs at its full rated power. So, for instance, if you run the calculation f

      • In short, their 'leadership' is artificial and shallow - bought and paid for, and likely only persisting so long as their market remains distorted by law. And your research missed a further distortion - a tariff on non-renewable energy that's used to subsidize renewable energy installations. (Which can then sell their power at the legally mandated above market rates.)

        • by kermidge (2221646)

          For a bit of perspective, the only condition where there can be a free market is anarchy. Once there is any rule of law in any political system (difficult to have one without the other, I think; in fact, to define one rather requires the other) there is skewed market because most law is economic law. Even in criminal law the bulk of it involves property in some form. (There is no way to use law to establish a level playing field; the very act of trying prohibits such - someone is always at a disadvantage

          • *Yawn* Sophomoric semantic games.... You, and every reader with even a smattering of education, know damn well what I meant.

    • by DrXym (126579)
      The real reason is their solar panels are not just efficient. They're ruthlessly efficient.
  • What happens when you only have 1 Sun? Or, more importantly, a fractional Sun since we have this nifty thing called an atmosphere.
    • Re: (Score:3, Informative)

      by qval (844544)
      Look at the graph at http://en.wikipedia.org/wiki/Solar_cell_efficiency [wikipedia.org] (about half way down). All the multijunction solar cells are run under concentration ranging up to ~1000 suns (1000:1 focusing of the suns energy). What's really impressive is that they are getting closer and closer to the 86% efficiency limit imposed by Carnot. Just like with Wind (~59% limit imposed by Betz's Law), our solar cells are approaching as good as we can get.
      • Re:297 Suns? (Score:4, Insightful)

        by Anonymous Coward on Thursday September 26, 2013 @09:26PM (#44966689)

        I do not think pholtovoltaics are limited by the Carnot efficiency, which applies to the conversion of heat to mechanical work in heat engines. The energy stored electrochemically in batteries can exceed the Carnot efficiency, as can fuel cells.

        • Carnot efficiency does apply, because it black-body radiates away energy as part of the process, and therefore is a simple heat engine to some degree. In fact, everything above absolute zero is, including fuel cells. They operate at lower temperature differences and therefore the effect is smaller, but it's there nonetheless.

          Further reading:

          https://en.wikipedia.org/wiki/Shockley-Queisser_limit

    • by geekoid (135745)

      There specialized cell for solar farms. They will be under a lens.

    • by timeOday (582209)
      You could use 2x2 cm lenses to focus onto a matrix of 1x1 mm cells underneath... boom, 400 suns. You would need to shift one or the other throughout the day as the sun moves though.
    • by dbIII (701233)
      You do it all with mirrors and thus don't have to make as much smoke.
      If that was too confusing, consider that mirrors are a lot cheaper than these solar cells so an array becomes a collection of dishes instead of flat panels.
  • I don't think we'd care what the efficiency would be if Earth had 297 suns. jk

    What's the actual efficiency when used at a single sun? Is this technique only useful with hundreds of mirrors?
  • Makes me suspect that this is anything but affordable.
    • by Gravis Zero (934156) on Thursday September 26, 2013 @07:24PM (#44965939)

      Multi-junction cells are expensive to produce, using techniques similar to semiconductor device fabrication, usually metalorganic vapour phase epitaxy but on "chip" sizes on the order of centimeters. In cases where outright performance is the only consideration, these cells have become common, they are widely used in satellite applications for instance, where the power-to-weight ratio overwhelms practically every other cost.

      • by Dan East (318230)

        Yet it can still be "affordable" because these are designed to achieve this efficiency at 297 suns' worth of energy. Thus you have 297 cheap 1 m^2 mirrors reflecting sunlight at just a single 1 m^2 solar panel. So if the panel costs less than 297 times the cost of a normal solar panel designed to capture a single sun's worth of energy, it is actually cheaper (not counting cost of mirrors or active hardware to aim the mirrors as the sun moves across the sky, but you get the idea).

      • by MattskEE (925706)

        Multi-junction cells are expensive to produce, using techniques similar to semiconductor device fabrication, usually metalorganic vapour phase epitaxy but on "chip" sizes on the order of centimeters. In cases where outright performance is the only consideration, these cells have become common, they are widely used in satellite applications for instance, where the power-to-weight ratio overwhelms practically every other cost.

        MOVPE/MOCVD growth methods are not inherently limited to small chips that are centimeters in size. Researchers might be growing smaller samples during R&D because of limited reactor sizes, and the expense and difficulty of handling large wafers. Once the technology is demonstrated on small wafers the design can be scaled up for growth on larger wafers.

        Commercial MOCVD reactors may grow on dozens of small wafers simultaneously in a single chamber, and the wafer sizes can also be increased. Commercial

      • I wrote the statement you quoted. Feeling proud now.

  • by Gravis Zero (934156) on Thursday September 26, 2013 @07:21PM (#44965909)

    Here is a graph of solar cell efficiency [wikimedia.org] showing the different kinds of materials used to make them. The typical solar cell [wikipedia.org] is silicon (blue on the graph) and maxes out at 27.6% efficiency.

  • Do they need rare elements? TFA does not say a word about it, and it is important: if the answer is yes, then it is not economically viable.
    • by bloodhawk (813939)
      These are likely to be used in price insensitive installations for now, e.g. satellites, where weight and efficiency count for more than the build cost.
    • Do they need rare elements? TFA does not say a word about it, and it is important: if the answer is yes, then it is not economically viable.
      What a nonsense. Why don't you check prices for rare elements? Or get an idea how abundant they actually are?

  • by rssrss (686344) on Thursday September 26, 2013 @10:46PM (#44967183)

    "Germany's Energy Poverty: How Electricity Became a Luxury Good" Spiegel 09/04/2013 [spiegel.de]

    German consumers already pay the highest electricity prices in Europe. But because the government is failing to get the costs of its new energy policy under control, rising prices are already on the horizon. Electricity is becoming a luxury good in Germany, and one of the country's most important future-oriented projects is acutely at risk.

    • Another Tea Party dream and Fossil Fuel industry hope. The more solar technology advances and begins to encroach on fossil fuel profits, the more of these "no we can't" nay-sayers come popping out of the wordwork. If solar cells go the way of IC's, the industry will replace fossil fuels entirely in 50 years. The future will be owned by those who invest in solar now. Its inevitable.

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