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Power Japan Science

Japanese Company Develops a Solar Cell With Record-Breaking 26%+ Efficiency (arstechnica.com) 133

An anonymous reader quotes a report from Ars Technica: The silicon-based cells that make up a solar panel have a theoretical efficiency limit of 29 percent, but so far that number has proven elusive. Practical efficiency rates in the low-20-percent range have been considered very good for commercial solar panels. But researchers with Japanese chemical manufacturer Kaneka Corporation have built a solar cell with a photo conversion rate of 26.3 percent, breaking the previous record of 25.6 percent. Although it's just a 2.7 percent increase in efficiency, improvements in commercially viable solar cell technology are increasingly hard-won. Not only that, but the researchers noted in their paper that after they submitted their article to Nature Energy, they were able to further optimize their solar cell to achieve 26.6 percent efficiency. That result has been recognized by the National Renewable Energy Lab (NREL). In the Nature Energy paper, the researchers described building a 180.4 cm2 cell using high-quality thin-film heterojunction (HJ) -- that is, layering silicon within the cell to minimize band gaps where electron states can't exist. Controlling heterojunctions is a known technique among solar cell builders -- Panasonic uses it and will likely incorporate it into cells built for Tesla at the Solar City plant in Buffalo, and Kaneka has its own proprietary heterojunction techniques. For this record-breaking solar cell, the Kaneka researchers also placed low-resistance electrodes toward the rear of the cell, which maximized the number of photons that collected inside the cell from the front. And, as is common on many solar cells, they coated the front of the cell with a layer of amorphous silicon and an anti-reflective layer to protect the cell's components and collect photons more efficiently.
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Japanese Company Develops a Solar Cell With Record-Breaking 26%+ Efficiency

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  • This is only single cell solar cells, multi-junction cells have breached 46%. https://www.ise.fraunhofer.de/... [fraunhofer.de] At this point increases in efficiency are mostly masturbation, relying on complex materials/techniques that aren't worth the cost. The big transformation will occur when they get thin film solar cells that are more efficient so you can have solar cells without making ridiculous amounts of toxic waste.
    • by Seequeue ( 713543 ) on Thursday March 23, 2017 @01:46AM (#54093729)
      There is a good graph on Wikipedia regarding research cell efficiency over time, and comparing all of the technologies at https://en.wikipedia.org/wiki/... [wikipedia.org]
    • by angel'o'sphere ( 80593 ) on Thursday March 23, 2017 @04:53AM (#54094069) Journal

      have solar cells without making ridiculous amounts of toxic waste.
      Production of solar cells does not produce "ridiculous amounts of toxic waste" ... no idea where this myth is coming from.

      BTW: traditional PV cells are produced in the same way as computer chips, CPUs, memory, and SSDs.

      • Manufacturing computer chips is an industry that looks clean (fancy, spotless manufacturing facilities), but is actually very dirty.
      • It's a standard, procedurally-generated right-wing parroting point that executes in any discussion about $NEW_GREEN_TECH:

        "$NEW_GREEN_TECH generates an incredible amount of toxic waste to produce, even more than $OLD_FOSSIL_TECH!"

        Veracity is not a factor in the algorithm, the statement is simply generated and echoed. It's interesting how right-wingers suddenly become concerned (if fact-deprived) environmentalists AND income-egalitarians ("The CEO of $NEW_GREEN_TECH company is going to get rich off the backs

    • by vinlud ( 230623 )

      This is laboratory stage, the hunt for better efficiency is still very useful. Other teams / companies work on industrialization of the newly found processes from a laboratory to create these things for a reasonable price. This is how science has worked for over 100 years now

    • Exactly. It's interesting research, but it hits diminishing returns very quickly. Cheap solar panels have gone from 8% to 16% efficiency in a few years. That's a huge win, because you get double the power output for the same investment. Getting up to 32% for the same cost will be a similar win, but that's a long way away.
      • The easiest way to get up around 32% efficiency is to stop using semiconductors and use concentrated sunlight to drive a turbine instead. Glass mirrors are fairly cheap per square meter.

        Solar concentrators don't work for residential solar, because of the need to track the Sun. But utility-scale solar panel farms beat residential by 2.5x on cost anyway. The panels cost the same in both cases, but all the other costs are much lower for a solar farm when you install them at ground level by the hundred thousa

    • This is the record efficiency obtained for a SILICON solar cell, and while the title may be slightly misleading by not clarifying the summary and articles are discussing Silicon cells. This is absolutely a record, and it is of great interest and importance since such a cell would be expected to give a lower cost per watt than multijunction cells.

  • OK, cool... (Score:3, Insightful)

    by Bartles ( 1198017 ) on Wednesday March 22, 2017 @09:44PM (#54093155)

    ...but solar cell efficiency only really matters when space is limited.

    • Re:OK, cool... (Score:4, Informative)

      by amiga3D ( 567632 ) on Wednesday March 22, 2017 @10:09PM (#54093259)

      The only thing holding me back now isn't efficiency, it's the cost of batteries. That's the real cost issue.

      • And while the cost per watt of the panels goes down (and from that the cost of shipping & installation), the cost of the inverter & other electrical wiring stays relatively fixed. It's way behind the panels & batteries but it is in the thousands of dollars per installation.

        • Yeah, this is pretty much the only reason I haven't set my house up with solar already.

          Hoping that by the time we have to replace our roof, it'll be relatively cheap enough to include in the cost though.

    • by Socguy ( 933973 )
      Not necessarily. More efficient cells mean that you can get away with fewer, lowing your costs to install.
      • by msauve ( 701917 )
        Your unstated and unsupported assumption is that the installed cost per watt is the same for cells of increased efficiency..
        • Panels of the same form factor with higher-efficiency cells install in exactly the same way. 255W panels install the same way as 180W panels and 355W panels (all of the same size). They rack up onto the same hardware.

          Oddly enough, the cost of micro-inverters for panels above 255W increases; and modern power-optimizing inverters actually cost the same, but fail less-often and provide more-efficient power regulation. The installation for string inverters, micro-inverters, and power-optimizing inverters i

      • can you show this mathematically?
      • Except that as you're going towards higher efficiencies, the price tag of the cells on the market rises more quickly than how their number in your fixed-power system decreases.
    • by vinlud ( 230623 )

      For a lot of applications of solar space is an very relevant factor

    • Shipping the cells requires more energy because they're larger and heavier. It requires more shipping hardware and energy infrastructure maintenance. It requires more handling to install them, wire them, and keep them free of the energy-robbing layer of dust. Manufacturing costs increase for an array with the same output, so decay from oxidization, delamination, imbalanced arrays and overvoltage, or plain old damage costs more--as does the shipping and handling, again.

      If I could get a single 2 meter b

      • It is impossible for a 2 square meter to output 6kW anywhere in the world. Even if you had a perfect solar cell that converts all forms of solar radiation to electicity at 100% efficiency you are limited to 1.361kW per square meter. You just can't make more sunlight.

        • That wasn't the point. The cost differences in shipping and installation are because the panels are of various sizes and weights; if I could get an impossible device that's a cubic centimeter, 3 grams, and generates 500GW of power, I could ship it via 32 cents of postage and install it in a few minutes of labor. Do you know how much it costs just to ship the concrete to build the nuclear containment building for a reactor?

          Moving material around requires time. Mining large amounts of material requires

  • Don't you worry folks... we got your coal jobs right here!!! that thar sciency mumbo jumbo is fer them Hollywood E-leetists... you won't catch me usin' no soLAR sells.... commie contraptions iffn' ya ask me!!!!
  • My solar panels are 14% efficient and cost 11 cents per watt.
  • by nightfire-unique ( 253895 ) on Wednesday March 22, 2017 @11:58PM (#54093561)

    Modern consumer solar is breathtakingly amazing.

    We forget how bad things were just 15-20 years ago.

    Earlier today, I set up a folding panel with sunpower cells; it was literally vertical, in a window, facing South. Total surface area.. maybe 3sqft, weighing 1lb. It was making ~20W for 4 hours, and managed to completely recharge my 130Wh battery pack in 8. Through a window. In the winter, in Canada.

    The thing cost $120.

    It's easy to get lost in the constant claims of breakthroughs while forgetting what an amazing time we live in. 20 years ago, this panel would have blocked out the sun and cost a months' salary.

    • Re: (Score:2, Interesting)

      by ledow ( 319597 )

      Good for you.

      The solar roof installed on my workplace (a large school) costs tens of thousands and won't pay for itself in 20 years.

      It isn't even warrantied for that long.

      It very much depends on where you are, not whether your panel is vertical or not (sure, it's BETTER to be vertical, but if you don't have enough sun in the first place, it makes virtually no difference).

      We even have one of those "this is how much energy you're generating, CO2 you've saved" screens inside the building it's on. It's curren

      • by shilly ( 142940 )

        How on *earth* did your school manage to install a large panel costing tens of thousands that can generate as little as 45W??? Can you provide more details? Cos this sounds pretty dubious. What time of day? How old is the installation? What was its rated generative capacity? Where is the school?

        I mean, a typical home installation generates 3kW, and costs well under 10k.

        • by MatthiasF ( 1853064 ) on Thursday March 23, 2017 @06:41AM (#54094309)
          They didn't. He's either lying or doesn't realize it's generating in kilowatts.
          • by Hodr ( 219920 )

            He sure as shit isn't generating 45kw for "tens of thousands"

            • Hey .. $90k is still "tens of thousands" and would just about do it.. :)

            • Price of solar is about $3 a kilowatt/hour. So, a 45kw system would cost roughly $135k before subsidies.

              It looks like he lives in the United Kingdom, which has subsidies at install and for production that could have cut the costs down below $100k om 2015 or 2016.

              Also, there's no telling if any of his numbers are remotely accurate either considering his position on the matter.
        • > install a large panel costing tens of thousands that can generate as little as 45W???

          He forgot to mention that it's night, and the only light is coming from the full moon and a street lamp in the parking lot.

          The real problem is: 'one of those "this is how much energy you're generating, CO2 you've saved" screens'. Some people just get hopelessly irritated by stuff like that. These panels could be great, making free power, steak dinners, good jobs, curing erectile dysfunction and shitting out Tiffany cuf

          • The ironic thing is that both the preppers I know and the hippies both actually like photo-voltaic technology. One camp likes it because it is off grid and frees them from being dependent on a central electricity system. Another camp likes it because it is not throwing pollution into the air. Plus, it is pretty foolproof. You can get electrocuted or have a panel fall on your head... but for the most part, setup is idiot resistant, especially compared to almost any other power generation out there. Plus

            • "Solar power has almost zero downsides."

              Apart from the massive amounts of nasty environmental waste being produced in China (where most come from) that's threatening the potable water of a few tens of millions of people downstream.

              Hydroflouric acid in particular is something you don't want in your waterways.

              In northern latitudes, you'd be better off thinking about solar heat panels and suchlike to offset your energy costs, but solar PV is generally a waste of space unless you're off-grid and away-from-grid

              • The reason I suggest solar heat panels is because they're cheap to manufacture and maintain, making the 5-10% potential heating costs saving worthwhile aiming for.

                If you wanted to get really whizzy you could store solar heat in the ground in summer and extract in winter but that's a massive complexity boost with long payoff period. On the other hand schools tend to have large open fields where the pipework for such systems can be laid relatively easily and deeply.

        • by ledow ( 319597 )


          This is the FOURTH school I've worked at that has the same problem. The others I've worked at have deliberately refused solar installs after doing the sums.

          In certain places, solar is just POINTLESS.

          I'm in the UK, a major developed country the same latitude as other huge centres of population the world over. (Please don't say "Ah, yes, in the UK you won't get...." - this is exactly my point, solar is not a panacea).

          And it's currently reading... ZIP. Literally I have to interpret the decimal points,

          • Someone fucked up.

            A correctly installed 10kW solar array at that latitude should peak at around 7kW. If you're seeing less than one, then someone fucked up the wiring, or most of the panels are defective. Fire whoever's responsible, and sue the company until they fix it.

          • by shilly ( 142940 )

            FFS, mate. I live in the UK too. Your figures seem ridiculous -- your school has been had. Here in Norf London, there are hundreds of houses with solar fitted that's charging Teslas. Couldn't do that if the conversions were as poor as you assert for your school. And there is no way that at 1pm on a cloudy day a 10kW system in the UK should be generating zero. That is mad.

        • maybe installed back to front
      • The solar roof installed on my workplace (a large school) costs tens of thousands and won't pay for itself in 20 years.
        Then the school got ripped of, it should pay itself in about 3 years.

        It isn't even warrantied for that long.
        Then you life in the wrong country and should demand better laws. In Europe such installations have a warranty of 20 - 30 years: by law.

      • Don't let that experience sour you on PV solar. What you're seeing has nothing to do with the technology itself; solar works extremely well, even at high latitudes, when installed correctly. Ask any sailor, NASA engineer, or grid energy systems expert.

        If you're seeing 45W during the day on a $10k+ array, sue the installer because it's malfunctioning.

        BTW - You don't want vertical panels except at the poles (or temporarily when mounted on a heliostat).

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