back to article Solar power towers overpower PV panels by 20X

A group of researchers at the Massachusetts Institute of Technology has developed 3D mounting techniques for photovoltaic cells that can increase power output per footprint by up to 20 times over that of fixed flat panels. "Our findings suggest that harnessing solar energy in three dimensions can open new avenues towards …

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  1. JP19
    WTF?

    Breakthrough?

    Looks like crap to me. How can a small panel at a fixed angle behave any differently to a larger panel at the same fixed angle?

    The sunlight per unit area of the earth's surface is fixed there is no way to get more power from a given footprint except by pretending the shadow cast by a vertical structure isn't part of the footprint.

    There may be some mechanical advantage in mounting smaller panels on a support structure but there is no breakthrough or revolution here.

    1. Anonymous Coward
      Anonymous Coward

      Re: Breakthrough?

      Maybe the guys at MIT know more about this than you?

      1. The Man Who Fell To Earth Silver badge
        Boffin

        Re: Breakthrough?

        This is basically what Solyndra's core IP was about - 3d solar cells that collect the sunlight very efficiently regardless of the angle of the sun, rather than flat panels. Their preferred implementation was cylinders, but the patents cover this MIT structure.

        In the end, the maximum solar flux is 1 kW per square meter, and nothing will change that.

    2. Franklin

      Re: Breakthrough?

      "Looks like crap to me. How can a small panel at a fixed angle behave any differently to a larger panel at the same fixed angle?"

      Well, the nice thing about the scientific method is that it relies on empirical evidence, not on what seems like what might make sense. It's easy enough to test whether or not their method of mounting panels results in greater power per unit area of ground it covers...

      ...which, apparently, they've done.

      1. itzman
        Headmaster

        Re: Breakthrough?

        The sleight of hand is of course in that phrase 'the ground it covers'.

        I can build a square mile of panel surface that shades two square miles of ground from the sun, and hang it from a crane. look at the ground the crane is resting on and declare that I have now 100 times greater power density.

        It is common for 'green' energy projects to make false and/or misleading claims - indeed renewable energy as a whole IS a false and/or misleading claim, but its rare for it to be as blatant as this.

        I am sure its slightly better than it was before, but as another poster points out, solar flux is 1Kw/sq meter of the planets surface, and if you collect that on a solar panel it wont be growing plants somewhere in their shade.

        The staggering thing is that people believe this stuff. A small advance in an insignificant industry blown up by media hype into something that will 'Save The Planet.

        1. david wilson

          Re: Breakthrough?

          I guess given a relatively slender tower, one advantage of this arrangement is that it *could* be combined with agriculture, since relatively little ground will be in shadow for long.

        2. Anonymous Coward
          Facepalm

          Re: Breakthrough?

          You beat me to it. By the looks of it, it's all it is.

          I was going to say "so, 10 times the efficiency by stacking 10 of them on a tower above your house?"

          Riiiiiiight. I think I could do with a few grand of investment money to "test" this theory of mine.

      2. mark 63 Silver badge
        WTF?

        15 Thimbs up for Franklin

        I cant believe Franklin has the highest amount of thumbs up for his comment

        "well science needs evidence and figures - which they say they've got"

        I've just re-read the the article looking for any evidence that they havent just incresed the power output per square foot by by stacking panels up (see my "bleedin obvious" comment , along with pretty much all the other comments)

        I still cant find anything special , unique or any kind of breakthrough or innovation here - could someone please explain?

        ALSO I BET they didnt include the area of the shadow that thing casts in the power/sq foot figure

      3. The Man Who Fell To Earth Silver badge
        FAIL

        Re: Breakthrough?

        And best of all, the MIT folks have no data!

    3. KitD

      Re: Breakthrough? @JP19

      Who said the small panels were fixed? This paragraph:

      "Perhaps more important than the successful models of such 3D mounts the team has tested, is the analytical software developed that can model different 3D configurations in a wide variety of latitudes, seasons, and weather conditions."

      suggests they can be manoeuvred into more efficient positions as the conditions require. OK, agreed, this has been done before in solar farms. Nevertheless, the improvements over the basic fixed panels used on residential rooftops seem possible.

  2. beast666

    You misunderstand the research. Check it out on physorg.com, which is where most science stuff on el Reg is regurgitated from anyway... I'll leave that compliant for another time. Don't bother reading their forum/comments though... There they be dragons. and trolls. and nuthatches. Especially nuthatches.

  3. jubtastic1
    Holmes

    "per unit of mounting area"

    This concept seems erily similar to my patent pending 'Nuclear Power Station Multiplier' design, where I show progressive power output increases per acre simply by arranging Power Stations in what I've come to call a 'stack'.

    1. Notas Badoff

      I see you're standing on the shoulders of giants, who're standing on the... Why it's genius all the way down!

      1. Anonymous Coward
        Anonymous Coward

        If...

        If I haven't seen further, it was because giants were standing on my shoulders...

  4. Uncle Slacky Silver badge
    Stop

    Trees got there first

    I'd have thought that imitating natural light-gathering structures would be the best way to go.

    1. Anonymous Coward
      Anonymous Coward

      Re: Trees got there first

      Indeed, previous research pointed to trees being a perfect 3D solar collecting structure..and it looks nicer than this abomination.

      1. Jolyon Smith
        Holmes

        Re: Trees got there first

        Tree's only have to worry about efficiently collecting light.

        They don't have to worry about commercial economics of building the structure to gather the light, then converting that light into energy and then supplying it into a power grid and doing so in a cost effective fashion that gives a return on investment to shareholders.

        It's amazing how much freedom you get to innovate when having to turn a buck is taken out of the equation.

        1. Yag

          Re: Trees got there first

          As if natural competition and selection won't work in favor of the most efficient designs - Eg. the best bang for the bucks... erm... available nutriments.

        2. Allan George Dyer
          FAIL

          Re: Re: Trees got there first

          s/commercial economics/biochemical costs/

          s/light into energy/light into sugar/

          s/supplying it into a power grid/supplying it into a vascular system/

          s/return on investment to shareholders/return on investment to acorns/

          Its amazing how much freedom you get to innovate when thwarting herbivores is taken out of the equation.

      2. Elmer Phud
        Boffin

        Re: Trees got there first - Bring me a shubbery

        Sorry to point out this one small item - I'm not too sure how easy it is to move trees about.

        Towers of PV? - easy

        1. Phil O'Sophical Silver badge
          Thumb Down

          Re: Moving Towers of PV? - easy

          No so easy when they're plugged in. Think roots.

      3. Anonymous Coward
        Trollface

        Re: Trees got there first

        One of the easiest ways is just to use trees. I don't know, perhaps chopping them into "wood" or something. Then "burning" it and finally using this as some sort of magical "fuel". We can make power from this. Then planting more trees.

        Oh, but for some reason digging all the materials up, refining it, producing solar equipment and wiring it into the grid is more efficient.

        1. Gorbachov

          Re: Trees got there first

          You answered it yourself. Burning trees is inefficient. Especially if you want electricity from them.

    2. Anonymous Coward
      Anonymous Coward

      Re: Trees got there first

      and indeed it has been done, some kid got national headlines last year for arranging solar cells in a leaf like pattern and claiming efficiency gains which were roundly debunked because he'd used a flawed method of measuring efficiency.

  5. The Axe

    Pointing down?

    Some of the panels seem to be facing down. How are they going to be collecting sun light?

    1. Yet Another Anonymous coward Silver badge

      Re: Pointing down?

      Reflection - cheap low efficency panels reflect some of the incoming light, especially at low angles of incidence. In this configuration any light that bounces off the main panel is absorbed by the

      other.

      If the signal is worth more than the detector it's a common way of making high efficiency photodiodes - putting a larger one facing back at the main receiver to catch any reflection losses.

      1. Anonymous Coward
        Anonymous Coward

        Re: Pointing down?

        Sure if you're trying to detect a tiny number of photons it's a fine way of making a sensitive detector but solar cells are about power and power is maximised when the sun hits the panel at 90 degrees incident angle. My understanding is that you can get significant open circuit voltage rises but available current doesn't increase (essentially a variable impedance source, dependant on incident angle)

        I wonder if there are more gains to be made from making the panels matt instead of shiny reflective. Of course then there'd be more heat to dissipate but perhaps direct coupling a water heating system to the panels would work and give plenty of hot water into the bargain.

        1. Anonymous Coward
          Anonymous Coward

          @ AC 0700

          * DEPENDENT

    2. Elmer Phud

      Re: Pointing down?

      Certainly in the UK it's often better not to try pointing stuff at the sun but to work on reflected light from clouds intead.

  6. JDX Gold badge

    pretty

    Could see some rather nice sculptures coming from this, nice and Sci-fi.

  7. Cupboard
    Mushroom

    It looks very like the second tower is always going to be in shadow, you can't magically increase the amount of sunlight per unit area.

    I think you'd be better off stacking solar thermal under PV, you reduce waste and it's not too expensive or complicated.

    Nuke, because it doesn't go off in the winter ;)

    1. Anonymous Coward
      Anonymous Coward

      "Nuke, because it doesn't go off in the winter"

      Actually, Fukushima Dai-ichi "went off" in the winter. Well, the day its meltdown and explosions began was March 11, 2011, which was rather close to spring – but you get my point.

      1. Anonymous Coward
        Anonymous Coward

        Re: "Nuke, because it doesn't go off in the winter"

        Actually, schools are teaching kids that spring is the beginning of March these days, because all the teachers are thick and so is everyone at the Met Office. Speaking as the first year of comprehensive school, I predicted 32 years ago to my final year junior school teacher, Mr Hope, that this appalling shit from the uneducated, would be one of an large number of inevitable demonstration of ignorance, created by giving up on teaching children to value facts at any level of rigour, innit.

        It's funny, with "fewer" versus "less than" being important today amongst the pseudos who wouldn't recognise an oak tree, (while remaining completely silent about every misconjugation of the verb To Be on Eastenders, "We was!" "'E were" and "Dispatch" seemingly ok among the many "Judgments", along with Billion no longer being bigger than a Miljard,) I heard some guy use fewer for a non integral comparator the other day, or more accurately fewest.

        Which is fewest, a ton'o sand or a metric one?

        Fucking shocking. I give up.

        Ignorance in bliss, I no longer care, I'm beaten. There was a day when I'd stand up and fight over an allegaton that Air France's concorde didn't land at Heathrow to pick up a few extra passengers en route to NY from Paris, but I'm just too old to give a fugue.

        1. Daniel B.
          Boffin

          Yanks beat y'all on that

          The US beat schools on that, given that DST begins at the beginning of March instead of "right after Spring", so maybe that's why schools are teaching the stuff like that. DST before the equinox does sound daft, doesn't it?

        2. Elmer Phud
          Headmaster

          Re: "Nuke, because it doesn't go off in the winter"

          History has so many simliar rants that go back hundreds of years.

          Nothing special, things change, even the meaning of words can reverse in less than a century.

        3. This post has been deleted by its author

        4. JDX Gold badge

          Re: "Nuke, because it doesn't go off in the winter"

          What is this pointless rant on about? No physical law defines seasons based on the equinoxes and it's far more sensible IMO to have seasons defined as 3 months each.

          1. Stoneshop
            Headmaster

            Re: "seasons defined as 3 months each"

            They *ARE* three months each, it's just that the change dates don't align with a calendar-month change

  8. John Brown (no body) Silver badge
    Boffin

    Dynamic v Static

    I wonder what the "greeness" difference is between using a dynamic set of panels to follow the sun for best light incidence and this big complex looking tower would be?

  9. Martin Budden Silver badge

    Wonder how they cope with strong winds?

    1. Stoneshop
      Joke

      "Wonder how they cope with strong winds?"

      The really nifty bit, not covered in the paper, is that as the shape adapts to the circumstances they turn into a wind generator at 5 Beaufort or higher.

      1. Cupboard

        Re: "Wonder how they cope with strong winds?"

        I've got some neighbours with a tracking array, in theory it's a brilliant idea but in any moderate gust of wind it flattens itself and production slumps.

        Unless they manage to get something sorted so that it works a bit more reliably they'll have been better off with a straight fixed one. Not as cool though!

  10. James Boag

    What is the optical properties of bird shit on these towers ?

  11. quartzie

    neighbours

    Many find the 2D solar parks hideous enough, care to explain how much opposition would these "beauties" gather once built anywhere near populated areas? Surely the efficiency would be at least 5x higher....

    1. itzman

      Re: neighbours

      Oh, they wont build them near densely populated areas.

      London has almost no power stations at all. It leaches and sucks like a huge parasite on the hinterland to provide its food, fuel and energy.

      The obvious place for an array of sun follies is right there in the National Parks where the wind follies already are.

      1. Anonymous Coward
        Anonymous Coward

        Re: neighbours

        I've seen a small one recently. Other than the colour, it looks much like a grape vine orchard. In that, you have rows of panels you can walk between. Not much different than looking at a field of cabbages. Not sure what the fuss is about. Although, I guess glare can be a problem. But that's down to planning, not the panels fault.

  12. Kirstian K
    Holmes

    Meh

    Im going to wait a little longer, and wait for some smart arse (probably apple) to design a self growing nano tree (theres the patent) that grows solar leaves and is therefore the most economical solar panel you can get. it will look nice as others have said.

    well if we can create self healing plastics etc, and have nano tech, surely this has to be on someones list.

    (bitter non south facing home owner)

    1. Kubla Cant

      Re: Meh

      "self growing nano tree ... that grows solar leaves"

      I think this is what they call "a bush".

  13. Yag
    Thumb Down

    The important point is...

    What is the efficiency per pannel sq.m compared to "traditional" pannels?

    Ok, I'll be nice and only ask for the efficiency per cubic meter of the footprint of those horrors...

    I'm sure that the tubular cells (http://www.theregister.co.uk/2012/03/01/tubular_cells/) have far more potential than this one...

    However, I look forward to the covering of skyscrapper with solar cells, just for giggle...

    1. Anonymous Coward
      Anonymous Coward

      @ Yag

      You do not qualify to participate in a discussion about technology if you think that the correct spelling of certain words is "pannels" and "skyscrapper".

      Spell checking functionality is available in popular browsers.

      1. Yag

        Re: @ Yag

        My popular browser have a tendency to propose a lot of words that may sound weird to you...

        Sorry for not being a native english speaker.

        Grammar nazi plus anonymous coward, very impressive combination.

  14. Dom 3

    Spring, Concorde

    DST in the USA begins on the second Sunday in March.

    What's this about an AF Concorde stopping off at LHR? Sounds unlikely. I'm guessing that the aircraft would need to take on some more fuel for one thing.

  15. mark 63 Silver badge
    FAIL

    Talk about the bleedin obvious

    Is it just me or this the most bleeding obvious research a university has ever researched?

    its basicly - if you make a stack of things , you have more of them.

  16. Anonymous Coward
    Anonymous Coward

    Perhaps my sourecwas wrong, or perhaps PV cells are much better now.

    A few years ago an friend (an electronics engineer) told me that at that time:

    The average PV cell (made from silicon) consisted of a significant number of sub-cells. This was required because they tended to burn out and the chips are designed to stop those failed sub-cells from causing the whole PV cell from failing completely.

    Also the average (mean) amount of electricity gained from PV cells over theire useful lifetime was about equal to the amount used to produce them.

    Can someone with more modern/accurate information confirm/deny if this is/was true?

    1. Anonymous Coward
      Anonymous Coward

      Re: Perhaps my sourecwas wrong, or perhaps PV cells are much better now.

      Nope, no true.

      The cells produce enough money/electricity to repay their purchase cost several times over their life time. Unless them manufacture is obtaining energy for a fifth-tenth of its cost it would be impossible to be true.

      The reliability of the cells is also very good, Minimum 80% at the end of 25years is the usual guarantee and this is through degradation more than failure.

      You source was talking b******.

  17. Beechdale

    These people should be thrown out of MIT for time wasting research. The trial models look like they were built by a five year old.

    Of course if you build a tower you can increase the kWh generation per square foot of ground space, but that isn't the need. And if you you want to build a tower, just mount the panels flat on the sides. The way they have it, some panels are pointing at the ground, or facing north, or have hard shading from the structure.

    I can't beileve a monkey would come up with such a dumb idea.

  18. Anonymous Coward
    Anonymous Coward

    Seen this before

    I'm sure I have seen this before whilst travelling along the road, with solar panels mounted on top of each other.

    This really isn't a new technique, it dates back to the 80's

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