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Power Technology

Clear Solar Cells Could Help Windows Generate Power 87

ckwu writes "The vast real estate of windows in office buildings and skyscrapers could be a fruitful field for harvesting solar energy—if lightweight solar cells could be made with a high enough conversion efficiency and appealing aesthetics. Now researchers at Oxford University report semitransparent solar cells that might do the trick. The team made solar cells using a perovskite, a class of mineral-like materials that have properties similar to inorganic semiconductors and show sunlight-to-electricity conversion efficiencies of more than 15%. The team deposited a thin film of perovskite onto glass so that the material formed tiny crystalline islands. The islands absorb photons and convert them to electrons, while light striking the empty areas passes through. The result was a semitransparent solar cell with a grayish tint."
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Clear Solar Cells Could Help Windows Generate Power

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  • The challenges for mass-adoption of solar cells having nothing to do with convenient locations to put them. Nearly all home-owners have a roof that they can access.

    The challenges for solar cell adoption are:
    Cost-effective manufacturing methods
    The market price of silicon
    Efficiency of conversion
    Storing the energy for when it's required (or moving it to where it is helpful)
    and Durability

    When those problems are REALLY solved, we won't need to have dark windows to generate our energy needs. And we wo
    • by Anonymous Coward on Thursday December 19, 2013 @08:18PM (#45741995)

      When those problems are REALLY solved, we won't need to have dark windows to generate our energy needs

      I think the point of this was that windows are already darkened in office buildings. The solar cells are just a different darkening process that has a nice side-effect of actually generating energy.

    • by dwywit ( 1109409 ) on Thursday December 19, 2013 @08:22PM (#45742027)

      What's the issue/s with durability? Mine are warranted for 80% of claimed output up to 20 years (BPSolar), the rooftop mounts are cyclone-rated, and the panels themselves are rated for hail up to (can't remember right now) size.

      I've had people ask me about this great offer they've had from some local start-up that offers them cheap chinese panels with a five-year warranty, and I tell them to say "no" until they are offered well-known brands with better warranties. At least those people were smart enough to ask around for advice and opinions - I suppose others who don't ask for advice and opinions might get stuck with poor durability.

      • Re: (Score:3, Informative)

        by Lumpy ( 12016 )

        These are thin film solar technology that has less than a 3 year lifespan. they lose nearly 30% of their power output withing 8 months. It is the same junk as the solar panels sold at Harbor Freight.

    • This isn't really intended for the home-owner. You're right there--I probably have more space on my roof than the square footage of my windows.

      This is for the tall office building in a city. Those tend to have more square-footage in windows than the space available on the roof.

      That said, I'd be curious about other buildings blocking the sun in a crowded area.

    • by timeOday ( 582209 ) on Thursday December 19, 2013 @08:27PM (#45742061)
      You are missing a big point. Windows already cost money. The added cost of making them produce power is all that needs to be justified here.

      Second, windows need not be "darkened" to provide solar power. Most of the energy in sunlight is not in the visible spectrum.

      • by Lumpy ( 12016 )

        Glass is $0.25 a square foot. Solar Cells that have any real efficiency and longevity cost $2.25 a square foot. The bog point is there is barely 10% offset on cost, and these same windows will generate less than 20% of what a normal panel can generate so their economy is even less. Add in losses by being vertical and not tilted to the sun and they will generate 5% of the electricity than a standard cell on the roof will.

        So yes, he is missing a big point, these things are worthless as a technology unless

        • Except there is no correlation between the cost of this new type of cell and traditional cells, since there is no silicon in these ones and the manufacturing process is completely different.

        • by timeOday ( 582209 ) on Thursday December 19, 2013 @09:08PM (#45742299)
          If you think the cost of glass at $0.25/sf has anything to do with the cost of the windows installed in an office building (or even a home) then you have never bought any.
          • by Anonymous Coward


            Look up the term "curtainwall" and you'll understand just how true the parent post is. There are entire engineering and construction companies that specialize in nothing but curtainwalls.

        • Right. This technology looks like a way to make less efficient PV cells, mounted in less efficient configurations, at a likely greater cost. Now, if you could get the cost down extremely low and have high durability, it might not matter that vertical mounting is not efficient. But it would seem to be more cost effective to make an opaque siding instead.
      • by dbIII ( 701233 )

        Second, windows need not be "darkened" to provide solar power.

        In a lot of places the windows are tinted anyway.

      • Did you RTFA? It specifically mentions that these windows are grey tinted.
    • by Ken_g6 ( 775014 ) on Thursday December 19, 2013 @08:29PM (#45742073) Homepage

      The challenges for solar cell adoption are:
      Cost-effective manufacturing methods
      The market price of silicon
      Efficiency of conversion
      Storing the energy for when it's required (or moving it to where it is helpful)
      and Durability

      The price of silicon isn't the biggest problem now. Solar cells are already at parity with coal in India [thinkprogress.org], and keep getting cheaper every year.

      Efficiency is generally sufficient. A house's whole roof can generally power it.

      Durability also isn't generally an issue. Solar cells usually last for upwards of 20 years.

      The primary challenges now are:
      Installation costs
      Electrical connection costs (i.e. an inverter)
      and Storage (or grid hookup costs)

      • by AmiMoJo ( 196126 ) *

        Those problems are all solved too (home battery packs have been available for some time). The only barrier left is the up-front cost.

      • The primary challenges now are: Installation costs
        Electrical connection costs (i.e. an inverter)
        and Storage (or grid hookup costs)

        Power companies lobbying for more obstacles and increased costs to be placed in front of consumers daring to consider panels.

      • Efficiency is generally sufficient. A house's whole roof can generally power it.

        I use my spare bedroom to host an Amazon AWS edge location, you insensitive clod! I need a lot more than a roof full of solar!

      • Efficiency is generally sufficient. A house's whole roof can generally power it.

        Unless the roof is covered with snow, like it is for several months of the year. Unless you live in the tropics.

        • by Anonymous Coward

          Plenty rooftop installs around here. Also plenty snow.
          You don't see covered panels until you have well over 2' on the ground.
          And even then it's generally only old-style panels on shallow angle roofs.
          So if you have panels getting covered several months of the year... why are you doing a PV install in northern Alaska?

      • The price of silicon taken at one moment in time is not what I meant by market price. Market price fluctuates and the silicon market is capable of large fluctuations.

        I live in the Seattle area. No they are not generally capable of powering a home. Only if you pick and choose where you will evaluate the criteria, are they.

        Durability is an issue when you live in the midwest where hail, ice and heavy snow can damage just about anything on your roof. You have to insure the solar panel, which then inc
    • The key difference between putting solar panels on a roof and fitting these windows is the electricity producing windows are fitted in place of ordinary glass windows.

      The cost of the units is offset by not having to buy ordinary window glass. That should make a difference in payback costs and break even point.

      • ...and people would have to pretend they like tinted windows.

        Being forced to have tinted windows is not preferred. You can bet that if these get put on some skyscraper, the boss's windows will be exempt from having these installed.
    • The problem is comparing a home owner to a corporation.

      Sure it's not as cost effective, and doesn't really address the main hurdles with solar... but it looks great on a PR report and it's certainly not coming out of the CEO's pockets.

    • by MillionthMonkey ( 240664 ) on Friday December 20, 2013 @01:28AM (#45743437)
      Another challenge is the fines and penalties for installing solar cells on your roof. [theguardian.com]

      An alliance of corporations and conservative activists is mobilising to penalise homeowners who install their own solar panels- casting them as "freeriders" - a sweeping new offensive against renewable energy, the Guardian has learned.

      These people are actually freeloaders but of course he can't say what they really are because of political correctness that forces him to use softer words like "freeriders".

      Further details of ALEC's strategy were provided by John Eick, the legislative analyst for ALEC's energy, environment and agriculture program.

      Eick told the Guardian the group would be looking closely in the coming year at how individual homeowners with solar panels are compensated for feeding surplus electricity back into the grid.

      "This is an issue we are going to be exploring," Eick said. He said ALEC wanted to lower the rate electricity companies pay homeowners for direct power generation - and maybe even charge homeowners for feeding power into the grid.

      "As it stands now, those direct generation customers are essentially freeriders on the system. They are not paying for the infrastructure they are using. In effect, all the other non direct generation customers are being penalised," he said.

      Eick dismissed the suggestion that individuals who buy and install home-based solar panels had made such investments. "How are they going to get that electricity from their solar panel to somebody else's house?" he said. "They should be paying to distribute the surplus electricity."

      I don't want sewage electricity being forced down my throat after it's been on some other guy's filthy roof already! I'm an American; I have a right to choose clean electricity!

      In November, Arizona became the first state to charge customers for installing solar panels. The fee, which works out to about $5 a month for the average homeowner, was far lower than that sought by the main electricity company, which was seeking to add up to $100 a month to customers' bills.

      IN THE BEGINNING God created heavens and the earth. The earth was formless and void, and darkness was over the surface of the deep, and the Spirit of God was floating on the surface of the waters. God said "let there be light" and there was light. God saw that the light was good; and God separated the light from the darkness with a thin film of perovskite on glass so that the material formed tiny crystalline islands. The islands absorbed photons and converted them unto electrons, whilst light striking the empty areas passed through. And God saw that it was good. Then God said "let the rooftops sprout with panels: panels bearing light from the heavens"; the ceilings brought forth electricity, freeriders yielding current with voltage in it, unto the grid. And God saw that it was good. Then to be fair he charged the freeriders $100 per month, which Arizona reduced to $5, for those who drilled the formless void of the earth for the Spirit of God, and have to distribute the unwanted surplus electricity. And God saw that it was good.

  • But .. (Score:4, Funny)

    by savuporo ( 658486 ) on Thursday December 19, 2013 @08:02PM (#45741885)

    Will they be available as a service pack for XP ?

  • by Anonymous Coward

    It seems that no headline or story is written anymore without these weasel words that render the subject matter impotent.

    Semi transparent cells could, but don't/won't.
    Semi transparent cells might, or might not and probably won't.
    Semi transparent cells may, but doesn't.

    How about we get some tech that actually does shit. Why can't the next headline read; not so spectacular evolutionary tech does get the job done and improves performance ~5%. It will cost more and then later cost less.

  • by Anonymous Coward

    Seriously, unless you can make these absorb energy only in wavelengths we actually don't want in the house, it seems like all we'd be doing is generating electricity, which we'd then burn trying to substitute the light we filtered out. If these capture either IR, or visible light (and they deffinately capture visible light), then we're just going to end up turning on more light bulbs, and heaters to compensate for them.

    • by Anonymous Coward

      Not only that but putting solar cells on the sides of buildings is stupid to begin with. Half of the building is always going to be in the shade just by the nature of being a building but when do you ever see buildings on their own? Only the outlying, south facing (in the us and Canada) building would be getting sun all day. Also the angle at which the sun bits the panels is so great that you will be getting only a few watts per square meter of available energy before electrical losses. Solar is only good i

    • by Anonymous Coward

      1) If you transmit all the sunlight in the wanted wavelengths into the house, you'd burn electricity trying to counter the sun heat with air conditioning. (You do keep the house well insulated, right? right??)

      2) Excess electricity can be stored in batteries and used at night or when cloudy.

  • When has aesthetics ever played a role in how the glass and steel monstrosities were erected? If the owner thought they could make some extra money, they'll be tacked on, no matter how ugly.

    Hmmm.. When did I get so cynical?

    • ...because the renters like aesthetics.

      It'd probably be cheaper to not put in windows (and not heat/cool a building with windows), but people like them.

  • I'm all for solar windows on buildings. It doesn't bring in that much energy per unit area, but on a large, multi-story building, the energy obtained can be substantial.

    This is useful for both on-grid use (to help lower power bills), as well as off-grid use (power to be stored in batteries and used with PSW inverters for very clean power in the structure.)

    Stuff like this isn't revolutionary, but with energy use, any step helps.

  • They already have these in Japan, made ironically by an American (good old USofA) company.

    • by Anonymous Coward

      Have any links about that? Preferably in English?

  • by Anonymous Coward

    The islands absorb photons and convert them to electrons


    • Really. It's called the photoelectric effect - some guy named Einstein wrote a paper about it about 100 years ago.
      • by Muros ( 1167213 ) on Friday December 20, 2013 @04:34AM (#45743939)
        Wrong. The photoelectric effect explains how electrons energized by photons can escape their atomic bonds. It does not involve photons being converted into electrons.
        • Photons can be converted directly to electrons (and positrons) in the process known as pair production, providing the photons are of sufficiently high energy. That is not, of course, what happens in the photoelectric effect, but I had understood the intent of statement in the summary to mean that light energy was being converted to electrical current, even though it was not phrased correctly at the most literal level..
  • Clear Solar Cells Could Help Windows Generate Power
    Clear Windows Could Help Solar Cells Generate Power
    Windows Could Help Solar Cells Generate Clear Power
    Clear Power Could Help Windows Generate Solar Cells

  • If I had grey windows, I'd get less heat from open blinds in the Winter. I'd have to burn more gas.

    That said, tinted windows on office building are already the norm so it could work in that setting. It all comes down to cost. Also, what kind of innovative code compliance will you need for wiring from every window?

    • Also, what kind of innovative code compliance will you need for wiring from every window?

      It won't be that bad with grid-tie microinverters for every pair of windows or so. The complexity is comparable to adding lighting.

    • by dbIII ( 701233 )
      Not for you then but OK for probably more than half the world's population that live where it's not so cold.

      Also, what kind of innovative code compliance will you need for wiring from every window?

      Scraping the bottom of the barrel beyond the edge of reality there. Without anything resembling a product yet there is no answer so you can fill the void with FUD. Why are you doing so? For something so pointless you must have a stake for meaningless FUD.

      • Dude, switch to a different strain or just toke once next time. The medical stuff is not like the ditch weed you smoked in high school.

        • by dbIII ( 701233 )
          So that's the sort of person you are - building a drug addicted strawman no less. Why do you get such a bunch of complete arseholes every time some sort of type of progress in an alternative energy is mentioned? I'm in the fossil fuel industry and see no need for such mindless attacks on alternative energies so what's your excuse?
          • Nerd fight! Nerd fight! Oh wait, I'm a participant. Would a disinterested 3rd party please mock us by shouting "Nerd fight! Nerd fight!"?

            Sorry but I think this is just another example of how the Internet is a flawed communication medium. I can't imagine that it would be like this at a cocktail party.

            I mean, try to imagine me with a beer in my hand saying, "Won't there be code compliance issues, since you're trying to route power around window frames?" and you immediately throwing down your martini an

            • Raising code compliance issues when the item has not got as far as a prototype is taking a bit of an end run around reality. Thus I enquired as to why you wish to raise such unfounded fears, uncertainty and doubt.
              I'm sick of such luddites that attack new technologies with such FUD when there is obviously no answer yet to the question raised. It's not even at the point where the standards that would be applied can be named let alone having something or a domestic electrician to wire up.
              5V? 9V? 12V? 110V? H
              • I don't think looking ahead to a future where this will require additional electrical code is "FUD". I'm sorry you don't see it that way. Let's say they did have a deliverable, and failed to consider installation issues until that day. Now *that* would be an "end run around reality". Anybody bringing product to market should definitely be considering how it will fit in the regulatory regime.

                And while we're on the subject of products that haven't hit the market yet; that's a much more obvious criticism h

                • by dbIII ( 701233 )
                  Keep on digging that hole luddite until you can't see the sun and then you won't have to worry about that pesky solar power.
                • by dbIII ( 701233 )

                  Anybody bringing product to market

                  This is the sort of thing I mean - it's in the lab, years away from a prototype, obviously NOT "bringing product to market" any year soon and you are pushing this line.

                  • I'm sorry I wasted so much of your time and mine. I should have simply responded to your first post with this [badskeptic.com].

  • From the makers of submarine screen doors

  • Windows will never generate power, it will always consume power and much more so than a sane OS.
  • These are great for homeowners with HOAs that would consider rooftop panels an eye sore and not allow them. The amount of electricity a typical single family home would produce from these probably isn't impressive, but on a massive scale, this could save a lot of dead dinosaurs. For those outside of a country with strict homeowner's associations, there have been legal battles leading to foreclosures about things as silly as what color an owner paints their trim. Yes, most HOAs (in the US anyway) would not a
  • Like Dubai.

    That said, the main barriers are the cost to make PVs, and the storage of the energy itself.

    Sunny climates could use the PV windows to generate electricity for cooling buildings, which is up to 40 percent of energy usage in a lot of the world, and even for vehicles to extend their running range, depending on the characteristics of the PV material.

  • And in case of crashing windows, you can see the blue screen of death.


  • Enron (later BP) Solarex pursued what were called Building Integrated PV panels back in the 90's, but abandoned the project (later sold to US Solar I believe).

    Solarex was using germane/silane-doped amorphous silicon deposition at the time. TFA doesn't go much into the actual engineering here.

    Main concerns, as always in PV, were efficiency and initial cost.

    What is new here?

  • Surely I'm not the only one that did a double take when I read that as "pervo-skite"...

I THINK MAN INVENTED THE CAR by instinct. -- Jack Handley, The New Mexican, 1988.