Slashdot Mirror

← Back to Stories (view on slashdot.org)

Pliable Solar Cells on a Roll

Posted by michael on from the you'll-be-covered-in-the-stuff dept.

klevin writes "New Scientist is running a story on someone else who's developed thin, flexible, photovoltaic cells: 'The thin and bendy solar panels can be stuck to fabrics, sheets or backpacks and promise a go-anywhere electricity supply.' Whatever happened to those sheets of solar cells that some university here in the US developed several years back? As I remember, the concept was that they could be draped across roof-tops and whatnot. Never heard anything after that." We had post about solar building clothing last year.

37 of 241 comments (clear)

  1. Hmmm. by krymsin01 · · Score: 2, Insightful

    Would be good to use as a solar sail, I bet.

    --
    stuff
    1. Re:Hmmm. by The_Dougster · · Score: 2, Informative
      Piezoelecticity is a force to voltage type thing and while pretty nifty, is unrelated to photovoltaic cells.

      For the laymen out there, I'll explain this in technical terms. If you have a roughly cylindrical quartz crystal, and if you squeeze it, the crystal lattices "snap" into an alternative arrangement which free's up some electrons and essentially produces a static charge. When you remove the stress, the crystal lattice snaps back into its rest state and wants its electrons back.

      Conversely, by applying an alternating current to a quartz crystal, you can make it physically stretch and shrink.

      Because a quartz crystal is somewhat like a spring, a given shape/mass/volume of it will possess a resonant vibrational frequency. If you apply a signal to the crystal at or near the resonant frequency, the crystal's vibrational magnitude will increase, just like the famous Tacoma Narrows bridge "Galloping Girdy".

      Piezoelectricity is a weird and wonderfull direct mechanical to electrical conversion phenomenon and it is typically used in electronics to convert a sloppy signal into a more precise one, or by utilizing higher harmonic modes, to multiply a lower frequency into a higher one.

      --
      Clickety Click ...
    2. Re:Hmmm. by The_Dougster · · Score: 3, Interesting
      Solar sail? Try relativity rocket.

      Just use the solar cells to power up a linear accelerator and shoot nuclei out the back at near the speed of light. If you can get 0.999c from a nucleus you get a tremendous thrust for one little atom. Remember, F mA when you approach the speed of light. Relativity rockets (super ion engines) are probably the best means of propulsion where electric power is plentiful but mass is dear. I'm sorry, but that tiny momentum of a photon is so small it is pathetic. Granted you get 2x boost for reflection vs 1x boost for adsorbtion, but 2 x 0 still equals 0. The only way to practically get around in space is to shoot nuclei out the back of a rocket engine at the speed of light.

      --
      Clickety Click ...
  2. Are there other applications besides clothing? by aheath · · Score: 2, Insightful
    I wonder if there are other applications that make more sense than clothing that can charge a cell phone.

    I think this type of material could be very useful to provide electricity in places that do not have access to a reliable electrical grid.

    How many watts are needed to run a a phone, a refrigerator, a radio or a computer?

  3. I can see it now by SuburbaniteFury · · Score: 2, Funny

    The new Apple fashion: instead of black shadow people in their iPod advertisements, everyone is now covered with solar panels. (This might actually help the batter life, though, so it's not a total loss.)

  4. WARNING by Dash'n'SlashDot · · Score: 3, Interesting

    God, solar panelling on the clothes. try to imagine the warning labels they would put on thee things: WARNING! DO NOT USE WHILE BATHING OR WHILE HAVING SEX. ... Don't laugh. You heard it here first. Expect it on your self-heating winter coats next year.

  5. Not really by Nomihn0 · · Score: 2, Interesting

    If I understand solar sails correctly, this is not how they work. Instead, they utilize the combined force of billions of subatomic particles radiated by stars hitting a parachute shaped foil to tow a capsule. This is why they are made to be exceptionally lightweight and large in their surface area.

    1. Re:Not really by krymsin01 · · Score: 2, Informative

      Yes, you are correct in that, but if you made the sail out of a large, lightweight, flexible solar panel, you'd be generating electricity and momentum.

      --
      stuff
    2. Re:Not really by Anonymous Coward · · Score: 2, Informative

      Oddly enough, not so much the force but the momentum. And not subatomic particals so much as light. Stars appearently make a lot of light. And that's why solar sails, as opposed to cells, are reflective. The radiation pressure equation would probably provide more insight into this should you wish to investigate further.

    3. Re:Not really by WalksOnDirt · · Score: 2, Insightful

      But unless they can make it much thinner, this WOULDN'T make a good solar sail.

      At "a little thicker than photographic film", it is probably too heavy to be a good solar sail material.

      (Yeah, I know you never said it would, but you do seem to be defending that position.)

      --
      a,e,i,o,u and sometimes w and y (at be if of up cwm by)
    4. Re:Not really by lightsaber1 · · Score: 2, Insightful

      Holy Crap! Am I the only one that read this as a joke? Geez, some people take things way too seriously...and whoever modded this "Insightful" as opposed to "Funny" needs to grow a sense of humour.

  6. Iowa Thin Film Technologies by Anonymous Coward · · Score: 2, Informative

    The poster might have been thinking about Iowa Thin Film Techologies...

  7. Flat vs. Flexible Info by sahrss · · Score: 4, Informative

    To address some of Klevin's confusion, since I've been following solar panel advancements:

    Thin, flexible cells have been around for a while. One reason they haven't caught on heavily is because they're nowhere near as 'powerful' (efficient at conversion) as hard panels. Did a quick search (don't take this data *too* seriously, but it represents what's normal); compare panels from these two pages:
    Flexible
    Solid

    Specifically, compare "Unisolar 32 watt flexible solar panel" from the first link to "Shell ST40 thin film CIS 40 watt solar panel" on the second. The flexible panel is 940 sq. inches and 32 watts, while the solid panel 663 sq. inches and 40 watts. Big difference in watt per area.

    I ended up choosing a big solid one to fit in the rear dash of my car; flexible would have been easier to deal with, but it won't fold, and produces less power. (I use the panel in my car to power my laptop/cell phone combo while camping and stuff, it's very cool and gets a lot of questions from random interested people!)

    Here's another chart to compare the two: Product Page
    Tried to find an efficiency rating chart comparing the two types, but no luck. The numbers are out there somewhere...

    1. Re:Flat vs. Flexible Info by RealUlli · · Score: 4, Informative
      You mean, like this?

      Cheers, Ulli

      --
      Simple things should be simple, complex things should be possible.
  8. sweet! by Cannedbread · · Score: 2, Funny

    i live in oregon and i really cant wait to get a solor powered raincoat. oh wait

  9. Cheap solar panels by Squalish · · Score: 2, Insightful

    Screw clothing to charge cellphones, etc. I can't think of a more petty use.

    The major impact of this tech has nothing to do with its portability/flexibility. The article estimates that the price for a final process fab will be about 1 euro per watt, compared to a highly competitive market which has so far only produced 5.6 euro per watt glass panels.

    Simply put, this would make photovoltaics as an energy source an order of magnitude more competitive, if the process is scalable.

    --
    People in Soviet Russia, however, appear to be afflicted with amusing juxtapositions of the aforementioned situation
    1. Re:Cheap solar panels by Squalish · · Score: 2, Interesting

      Okay, was reading the wrong data, that was peak price, the lowest prices one can find are around E2.66 per watt for crystalline + E3.15 for thin film.

      Still, 1 euro per watt would make a HUGE difference in the viability of solar.

      --
      People in Soviet Russia, however, appear to be afflicted with amusing juxtapositions of the aforementioned situation
  10. Re:But what will the Terrorist implications be? by HillBilly · · Score: 2, Insightful

    Get over the terrorist thing. Stop letting them win with your paranoid thoughts.

    --
    "Go into the hall of mirrors and have a bloody hard look at yourself" - HG Nelson
  11. Solar Cells on a Roll by fireboy1919 · · Score: 3, Funny

    I don't care what anyone says.

    Now matter how pliable or environmentally friendly, solar cells are not good on a roll. They taste absolutely nothing like butter, and quite frankly, I find them barely palatable.

    Don't the editors try this these things themselves? This is as bad as that "http://slashdot.org/article.pl?sid=02/10/28/18522 41&tid=126" story. Trust me, those things taste absolutely nothing like fruit-rollups.

    --
    Mod me down and I will become more powerful than you can possibly imagine!
  12. Is $US52 per square metre about right? by thorpie · · Score: 4, Informative

    They quote 7% efficiency, 1 euro per watt.
    Full sun is 1000 watts/sq metre, so with 7% efficiency we get 70 watts/square metre, so it has a cost of 70 euros/sq metre or, at 1.33 euros to the dollar, about $US52.60/sq metre.
    Cover a 10 * 4 metre area of roof for $2,100 and get enough energy, in the middle of summer, to boil your 2 kw electic kettle all day.
    At 12c per kwH for electricity, @ 2.8 kw * 6 hours/day * 365 days/year gives a cost saving of $735 pa, or a repayment of the $2,100 capital in 3 years

    Are these numbers OK?

    At this price will it be practical to disconnect from the grid sometime soon?

    --
    The memories of a man in his old age are the deeds of a man in his prime - Floyd, Pink
    1. Re:Is $US52 per square metre about right? by DustyShadow · · Score: 2, Informative

      I think you 1.33 US dollars to 1 euro.

    2. Re:Is $US52 per square metre about right? by drphil · · Score: 5, Informative

      Although there is nothing wrong with your calculation per se, there are a lot of costs it doesn't include, so it is low by quite a bit. The 1 euro per W (peak Watt or average W - article doesn't say) is only the cost for just the solar cell at high volume manufacturing. At that point you are still quite a long ways from installing this on your roof cost-wise. You still have to put the solar cell in a module, then install it in a panel, then install the panel on your roof along with a rectifier (since your house expects AC) plus other equipment and power storage if you want to be competely off-grid - there are costs, of course, each step of the way.

      The rule of thumb I came across when I was studying the econ of solar cells ~18 months ago was that for thin film cell solar to be viable (without govt subsidy) it had to be manufactured for $1/pW (or one euro, depending on exchange rate) and had to have at least 10% efficiency. If the 10% efficiency is not met then the downstream costs eat you alive because you have to install so much more area of solar cells to get the required power.

      The current advances in flexible solar have been excellent and the solar market is growing at ~30% (although still >90% c-Si cells), but unless you are willing pay a price to be "green" or your govt gives you a fat subsidy for installing the solar power it will take you many years to repay your capital - on the order of 10 or more if you currently have ready access to the power grid. If you are remote from the grid, solar is actually a great deal cheaper today - but by using Si-based solar which is manufactured on relatively large scale today and has 15% efficiencies versus thin film.

      Govt subsidies are still going strong in Japan - Germany is wavering. With G(lobal) W(arming) Bush in office the increase in solar in the US is going to be from the Eco-minded willing to take a bath $$-wise or off grid applications - well, there are also cats who are pretty good at utilizing passive solar power.

    3. Re:Is $US52 per square metre about right? by DaChesserCat · · Score: 2, Informative

      Let's say it's 1 Euro/watt. That's about $1.33 USD/watt, or about $1,330/kW.

      The next factor to consider is the solar insolation for your area. This tells you how many hours of direct sunlight you get, for your area, each day. In my case, the annual average is about 4.5 hours / day.

      At that rate, 1 kW of photovoltaics will give me about 4.5 kWh of electricity, per day, on average.

      Also in my area, electricity is about 7 cent/kWh. Consequently, that 1 kW PV array will save me about 31.5 cents/day, on average. Thats 4,222 days (about 11 years and 7 months) for payoff. If your area gets more direct sunlight, or your electrical rates are higher, your payoff period would be shorter.

      That's the bare, basics of the whole thing. Don't forget: PV makes DC current, but most of your household stuff runs on AC, so you'll need an inverter. Count on a low four-figures for something that can handle the load for a small-medium household. Also, to go off-grid, you'd need some kind of batteries for energy storage (otherwise, the power goes out when the sun goes down), as well as a controller to regulate power to/from them, etc. That gets really expensive, really quick. Consequently, while you may not be able to go off-grid, you could probably do net metering and reduce (if not eliminate) your electric bill.

      --
      ... by the Dew of Mountains the thoughts acquire speed, the hands acquire shakes, the shakes become a warning
  13. Weight is the key... by The+Kiloman · · Score: 3, Informative

    Usually people imagine solar sails as being made of a very VERY thin film,on the order of a few micrometers thick... the point being that there's very little additional mass created by the sails themselves since you need so much surface area to create any appreciable force. Also, the less mass that's used for the sails, the more mass that's available for payload (or just plain not there, which means greater acceleration).

    Here's a few links (thanks Google and the obligatory Wikipedia):
    A geocities-looking site with some usefull info
    Planetary Society has some more info
    Wikipedia entry

    --
    You may disagree, but to be blunt, you're wrong. -tgd
  14. Re:But what will the Terrorist implications be? by LordEd · · Score: 2, Insightful

    It didn't say it was ultra-powerful, it says it was thin and cheap in trade for efficiency (and possibly usefulness)

    A truly inventive person can use anything to any purpose. Don't fear the technology, fear the people using it. If we abandoned all technology used by terrorists, we'd be living in caves and the government would be licensing the use of fire, wheels, and hammers.

    -- guns don't kill people, kids playing video games kill people

  15. thank you, my error, cost around $US93 /sqm by thorpie · · Score: 2, Insightful

    Thank you, so a cost of $93 sqm making close to $4,000 to cover 40sqm, or a repayment time of 6 years. Not so good, They won't get you to disconnect from the grid

    --
    The memories of a man in his old age are the deeds of a man in his prime - Floyd, Pink
  16. Electricity is only a small part of the game by dr.Flake · · Score: 2, Interesting

    What amazes me is that all this investment time and "energy" is spent on cells that produce electricity.

    Whereas the collection of Heat is as simple as it can get, but rarely used.
    Though most mediteranian countries use solar heat for heating their domestic water, but that is about it.

    What i have in mind is the use of solar heat, collected during summer, to warm domestic homes during winter. (Thats where real amounts of energy (read CO2) are needed !)
    Water is an exellent storage container for heat and is dirt cheap.

    The only problem is where to store all the warm water. Probably the easiest solution would be to pump up ground water, heat it, and pump it back. (The ground is actually an exellent therman insulator!)
    Use the 1kW of solar energy from a couple of M2 of these cells to make water run through 100 m2 of cheap solar heat collectors.

    Now we are SAVING evergy.

    --
    Why are other peoples sig's always more witty ???
    1. Re:Electricity is only a small part of the game by TheLoneCabbage · · Score: 4, Interesting

      Most solar researchers in this veign are using Sodium Cloride (table salt). It has a much higher specific heat than water. Tends to be less explosive when heated to 600c (you really want to build your house on top of an aging steam boiler with the equivalent energy of dynamite?), and is even cheaper than water and dirt (water aint cheap where I come from)! When molten it's conduction of heat is so efficient you don't even need pumps, it's own confection currents do the work for you.

      Now you just need a near perfect insulator and your all set. (say an underground tank insulated with airogel)

      The real trick isn't in just heating homes though. It's also running things like ovens and stoves. For that your going to need a liquid that stays a liquid between -10c and 250c, without dangerous pressure build up, freezing, corroding or screwing up your pumps. (and it can't pollute the environment when it leaks)

      Once you can safely transport high temperatures 2-3 times boiling point, you can do some pretty amazing things. Like running your A/C from the heat well. (two sterling engines hooked up to eachoter in reverse) Water pumps, air tools, and electrical generators (40-50% efficient in sealed systems like sterlings, but much higher for open ended boilers. The trick as you put it is to avoid converting the energy from one form to another untill it's absolutly necesary.

      --
      I would rather be ashes than dust!
    2. Re:Electricity is only a small part of the game by Oligonicella · · Score: 2, Funny

      Please tell me you don't ice your cake with salt.

  17. Re:Price per watt is what matters by humbads · · Score: 2, Interesting

    Yes, you will get rich. If a $1000 investment yields $0.50 per day worth of electricity on average, then that results in $182.50 per year in revenue. Assuming no maintenance, land, installation, or other overhead costs, you are earning 18.25% yearly on your investment. It would be like printing money!

  18. Re:But what will the Terrorist implications be? by berkut7 · · Score: 2, Funny

    Oh no! Ossama got an AA battery!

  19. Re:Wonder... by wish · · Score: 2, Funny

    1 Sheet A4 10 Euros probably meaning at least 9 euros or 9-10W
    A4=0.0625 m^2 IIRC
    So 1m^2=144-160W

    Add suitable number of pinches of salt.

    Alternatively find out how efficient regular solar panels are and reduce the power output by 50-65%.

  20. Solar Power on the Go by ElDuderino44137 · · Score: 2, Insightful

    I think solar power would be great for my home,

    It spends a lot of time out in the sun.
    But my clothing?
    I don't spend nearly as much time in the sun as my home does ;)

    Cheers,
    -- The Dude

  21. www.oksolar.com/roof/ by 6800 · · Score: 2, Informative

    www.oksolar.com/roof/ You can start there :-)

  22. And you can buy them by Migraineman · · Score: 2, Informative

    TFA talks about the product entering mainstream production in a couple of years. You can purchase the Iowa Thin Film solar cells now. They're about 7% efficient, as they claim. They're not expensive, and you can get them at a number of distributors. I've personally used Jameco and Sundance Solar.

  23. Solar power? by galenoftheshadows · · Score: 2, Informative

    Several U.S. Companies now provide solar shingles, in fact, my company has two vendors that carry them, they're just not quite popular yet because they're still a tad pricey.

    --
    Galen
    In your face, and always right!
  24. Re:Didn't RTFA, but... by clonan · · Score: 2, Informative

    We are actually unlikly to get much past about 50%

    This is the best plant chlorophyl (sp?) systems can get. It is also sad but true that it is extremly rare that machines, silicon or other, significantly out do nature in efficiancy.

    HOWEVER, since the average solar energy hitting earth is 1.4 kW/m^2 that means that even at 50% we are taking in 700 w/m^2. Now since the average energy use for a home is 17,130 kw/h that means we will need an average of 24-25 square meters to power a house.

    Then of course there is no light at night so we will need to double the area to 50 square meters and add a battery system.

    But REGARDLESS at even 50% efficiency we can power most single family american houses with simply the roof area!