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Solar Tree Bears Fruit

Posted by Soulskill on Sat Dec 29, 2007 09:22 AM
from the functional-art dept.
Power Hardware
Hugh Pickens writes "A prototype solar tree that recently went on display on a busy street in Vienna, Austria has passed a key test by providing light during the night-time even when the sun had been blocked by clouds for four days in a row. The branches of the solar tree were decorated with 10 solar lamps, each one powered by 36 solar cells. The tree included rechargeable batteries and electronic systems to measure the amount of light in the atmosphere and trigger the solar lamps to go on. 'Not just trees but other objects could be decorated with solar cells and so keep streets well lit at night time,' said Christina Werner from Cultural Project Management. Google uses a similar concept to light their parking lots with 3,000 solar panels that provide up to 10 percent of the Googleplex's power demand. We discussed Google's solar initiative last year."
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Submission: Solar Tree Bears Fruit by pickens (49171)
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  • The question is... (Score:3, Insightful)

    by Anonymous Coward on Saturday December 29 2007, @09:33AM (#21848316)
    How much non-renewable energy does it take to produce each solar tree?

    • Re: (Score:3, Insightful)

      by Adambomb (118938)
      What i'd want to know is how many existing street lamps could just have struts affixed to the sides to allow more attachment points for the PV cells and lighting on their own? Why does it have to be a single new unit to begin with.

      • Re: (Score:2, Interesting)

        by h4rm0ny (722443)

        Well, looking at the photo, it's certainly prettier to look at than most street lamps. Just a bit of a futuristic, more organic look. I like it. And it certainly gets more publicity than bolting some panels on top of an existing lamp. Besides, this is a prototype, so maybe you'll get your wish and the actual approach taken by city councils will be to adapt existing lights.

        We should never give up our appreciation for elegance.
        • Touche, I wasn't even considering the "shinyness" aspect when one is first pitching a technology to the suits behind the table =)

          thats a really good point heh.

          • Thanks and good of you to say so. Sadly /. mods fail to agree as I'm "Offtopic" now apparently. No more posting about solar powered lamp posts in an article on solar powered lamp posts for me then, eh? Bad Harmony! :D

    • Re:The question is... (Score:5, Interesting)

      by NorbrookC (674063) on Saturday December 29 2007, @09:49AM (#21848430) Journal

      How much non-renewable energy does it take to produce each solar tree

      If that were the only energy concern, then you'd have a point. It probably does take more energy in the beginning to produce it. However, the better (and more relevant) measure is total energy consumpption over its lifespan. That is, compare the manufacturing energy + energy use from grid + maintenance (replacement bulbs, etc.) over its projected lifepan to a standard lighting system. If it turns out that the overall energy used is less than that of a standard one, you come out ahead. You could also do cost analysis, but any pilot system has a much higher cost than production systems.

      • Re: (Score:3, Insightful)

        by jacquesm (154384)
        you should also factor in the disposal costs of the batteries, that probably is the largest factor.

      • Re:The question is... (Score:5, Insightful)

        by MindStalker (22827) <jlarsen@@@fsu...edu> on Saturday December 29 2007, @10:44AM (#21848852) Journal
        You also need to factor in the public safety benefit of it working even if the electricity is out. A whole city that stays lit up during a disaster could be very beneficial.

        • Maybe but there's also the risk of having the light out due to bad weather: I doubt that much light could be produced if there was too much fog on the city..

          • Re: (Score:3, Informative)

            by Telvin_3d (855514)
            Well, the point of the article is that these things are working after 4 days in a row with almost no sunlight. Sounds reasonably robust to me.
            • It's neither new nor hard. My solar garden lighting has at least that performance and at least that many lamps (high brightness LEDs) and will go a week without direct sunlight (it'll probably do more, but I don't think we've had a stretch of bad weather that long). It has an 80w peak panel, and a standard lead acid battery as storage (just the one).

              The "daylight measuring electronics" are bone simple, it's just a simple comparator chip (costing pennies) that compares a reference voltage (taken from the bat
        • Being able to more cost-effectively light larger areas also makes cities safer at night; this helps reduce crime which helps the economy, and also improves quality of life for citizens. The technologies will also improve as time goes on (more efficient solar panels, cleaner production methods, better/cleaner batteries etc.), so this is likely the way of the future. Even if the fixed costs (e.g. installation) are higher, the variables costs will almost certainly be miniscule.

        • You also need to factor in the public safety benefit of it working even if the electricity is out. A whole city that stays lit up during a disaster could be very beneficial.
          If the disaster is snow or ash: no light.

    • Re:The real question is... (Score:1, Funny)

      by Anonymous Coward
      how much energy is going to be wasted on replacing the stolen cells ?
    • How much non-renewable energy does it take to produce each solar tree?

      I presume you meant to try to revive the tired old myth that solar cells take more energy to manufacture than they produce over their lifetime?

      Simple argumentum ad absurdum:

      We (the continental US, but this applies to most places on Earth) receive 5.5 useful sunlight hours per day, on average.
      Modern solar panels have an effective lifespan of at least 20 years.
      That gives 40k hours over which a given panel can repay its initial cost

      • We (the continental US, but this applies to most places on Earth) receive 5.5 useful sunlight hours per day, on average.

        On average, maybe, but it doesn't make NY or Washington get as much sun as Texas. You'll get a better ROI the farther south you live and the less cloudy the atmosphere is.

        Modern solar panels have an effective lifespan of at least 20 years.

        Is that taking into account hail storms and other forms of damage that happen in non-ideal conditions? I've seen hail leave dents in cars, I'd imagine that would be pretty devastating to a solar panel array. I'd imagine they'd also be pretty useless when they're covered with snow during the winter.

        The cheapest commercially-manufactured home solar panels currently cost $3 per Watt.

        Is that just the panel cost? If so, tha

        • Is that just the panel cost?

          The argument I made applies to the myth that solar cells take more energy to create than they will ever produce. While you make a few good points, they don't really apply to supporting or refuting my argument.


          On average, maybe, but it doesn't make NY or Washington get as much sun as Texas.

          True... but you could also look at the flipside of that - In a Southern state, you'd do considerably better than the average.


          Is that taking into account hail storms and other forms

          • Re: (Score:3, Interesting)

            by h4rm0ny (722443)

            I haven't seen "real" (ie, damage-causing) hail since 1980 or 1981, and when it does happen, it tends to happen over a small area. I'd call that a low enough probability event to ignore. As for the more general "accidental damage" category - Well, does your house have windows? Do you need to replace them all every few years due to baseballs or hail or meteorite damage?

            Didn't anyone see that indestructible monitor a few days ago with the crystal screen? Okay, it's not actually indestructible but it's a tr

          • What if you factored in the costs incurred by reduced air quality from the coal power that you currently consume? While you may not personally pay those costs, other people do. Would photovoltaics be worthwhile at their current price if we could quite literally all be breathing a little better for your installation?
        • OK, that's fine - now after that 5.5 hours how did you store that energy? Or are you just done for the day? Does the battery system last 20 years as well?

          First, see my other response in this thread. [slashdot.org]


          Second, do you have a refridgerator? AC or heat for a significant part of the year? A home file server or even just an always-on DVR? Anyone home during even a portion of normal daylight hours, such as a child after school, or yourself on weekends?

          I originally posted on this topic to refute an all-too-
            • The only way it would benefit me much is if I had a reciprocal agreement with someone in a different time zone who had light when I need power and I had light when they needed power.

              Or, say, your own employer during the hours you work - Thus we have net (or "reverse") metering [wikipedia.org] to let you do exactly what you suggest.



              So if storage isn't really an issue, then solar power doesn't buy me a thing.

              You don't own a refrigerator? That alone quite likely accounts for a third to half of your electric bill, p

  • Solar Electric Baobab Tree (Score:4, Insightful)

    by G4from128k (686170) on Saturday December 29 2007, @09:43AM (#21848388)
    With a few minor changes, this "tree" could collect the rain water that runs off the solar panel and store it in its "trunk." Then, it would slowly release the water during the night to water the plants around the base of the tree. The result would save water and create a literally greener environment.
    • In Soviet Russia the trees pee on you!
    • Why would that be needed? That water reaches the soil anyway if it's raining.

      On top of that, we get plenty of rain in these regions (Austria/Western Europe), so there's no need for irrigation. In places where they do need irrigation, there's not much rain to collect, methinks :)

      • Re:Solar Electric Baobab Tree (Score:4, Insightful)

        by turgid (580780) on Saturday December 29 2007, @10:08AM (#21848600) Journal

        Firstly, the water that reaches the soil when it's raining mostly flows over the surface and into drains. If it were stored and released slowly, it would be more effective at watering the plants since it would have time to penetrate the surface. Also, being released at night it would not be subject to evapouration caused by sunlight.

        I also imagine that these solar trees will function in all countries, not just Austria, or those in Western Europe.

        • I also imagine that these solar trees will function in all countries, not just Austria, or those in Western Europe.

          Region encoding can solve that problem.
        • Incorrect. This is a problem that exists, you don't spend much time in grounds keeping do you? This is why cities send water trucks around. Your statement about evaporation is incorrect as well. During a heavy rainfall in the city most of the rainfall runs into the nearest storm sewer, it doesn't evaporate. This means that during seasons defined by heavy bursts of rainfall followed by long stretches of high heat and sunlight, soil moisture can become a problem. This could actually increase the amount of

  • Google uses a similar concept to light their parking lots with 3,000 solar panels that provide up to 10 percent of the Googleplex's power demand.
    So lighting the parking lots uses 10% of the Googleplex's power?
    How big are their parking lots?
    • I think they meant the panels in the parking lot provide up to 10 percent of the power. They are also called Solar "Trees" even though they appear to simply be overhangs with panels on top of them.
    • I guess they're probably using the generated power for more than just parking lot lighting. TFA is unavailable though, so I can't check if I'm right.
  • I believe Vienna is in AUSTRIA.

  • Looks promising (Score:3, Interesting)

    by dysfunct (940221) * on Saturday December 29 2007, @10:06AM (#21848584)
    A better picture of that tree can be found here [vienna.at].

    As a citizen of Austria, I find it quite astonishing that this thing was able to provide light for a couple of days, although I have to admit that compared to now October still had plenty of daylight. I don't know whether or not they have been removed from the streets, but it would be pretty interesting to see for how long they can go in December/January, when it's quite dark throughout the entire month.

    Apart from the energy savings, though, I wouldn't necessarily want to see them implemented throughout the city. Most of the 1st district's lighting is quite dim, giving the whole city with its many historic buildings a bit of a romantic flair, which - in my opinion - would be lost with all those bright lights everywhere.

    • You are at a lower lattitude than where I am and I have had only 27 solar heating hours since the end of November. This is off the readings for my Solar heating array, I know the solar PV array has not had much to it as well, but it's only running the garage and the battery is still topped off, but I barely spend any time out there as the solar heat array is only keeping the garage just above freezing due to so little direct sunlight. I get some heat from the vents on bright overcast days, but nothing lik
  • ... or heard or read about it. Anyway, this tree seems to be rather a piece or art than anything that is likely to go into mass production anytime soon.

  • Very inefficient compared to grid-tied panels (Score:4, Informative)

    by originalhack (142366) on Saturday December 29 2007, @10:16AM (#21848650)
    So long as fossil fuels are being burned to make power during the day, it is far more efficient to take the daytime output of the most cost-effective possible panels (usually nice unimaginative rectangular ones that mount on existing roofs or new carport structures) and feed it directly to the grid to reduce the load on the inefficient plants that peak during the daytime. There is no reason to lose a major chunk of the power charging batteries, to build expensive battery arrays or to build bizarre structures to support the cells.

    At night, the worst power plants are throttled back or shut down and the most efficient plants are handling the load.

    When no further fossil fuels are used to make daytime power, then storing electricity from daylight becomes interesting and, even then, batteries are a loser.
    • Mainstream environmentalism is all about PR and raising awareness. A street lamp with a solar panel on the top connected to the grid doesn't make quite as profound a "we're doing something for the environment" statement as does a lamp that powers itself and will even run for days on minimal input.

      Earth Hour [wikipedia.org] was even more useless than this, but most people are stupid and need to be treated like little children with silly gimmicks to get them to pay attention: turn the god damn light off when you're not usin
  • Why bother going to the trouble of milking high quality renewable energy from the environment if you're just going to waste it on something frivolous like keeping an empty expanse of pavement lit up for eight hours a day!? If we stopped frittering away energy on pointless things like lighting empty parking lots, we'd have a lot less to worry about in terms of energy security. Even the big G doesn't get it.
    • The reason empty parking lots are lit at night is for liability reasons. Car accidents, muggings and rapes are some examples of such liabilities. Crime prevention is another one. Car break-ins and things like house intrusions are all easier to accomplish in the dark. Lighting the city at night is seen by governments as due diligence, much like scraping snow off the sidewalks, and sanding icy intersections.
  • From the photograph I'd love to see these effective at a 20 - 30 degree slop from horizontal so as us folks who get SNOW could still utilize these without them becoming a catcher's mitt for heavy snowfall.

  • There are commercially available solar street lights [solarlighting.com] in the US. 5-day battery backup, resistant to 150MPH winds. "During the 2004 hurricane season in Florida, SLV models withstood ground zero wind conditions from category 5 hurricanes and typhoons." Just what's needed to provide light during emergencies.

    The "Solar Tree" is more of an art project.

  • When will those fucking assholes stop polluting just about every square millimeter of our planet with artificial ugly light?! It's totally outrageous that just about nobody alive today has actually ever had the chance to experience why we call the milky way the milky way.
    • Sure, lets just have entire economies shut down at night so that nobody would need those lights, burglars can invade peoples' homes at night with impunity, raping and pillaging and no worries about witnesses. In fact, lets all move underground into caves, then there'd be plenty of reason to run the lights because there'd be no sky to defile. Brilliant! Now where's my goddamned night vision goggles?
  • when someone invents a cheap way to illuminate a whole city during nighttime, amateur astronomy will die :(
  • Please use solar power to replace fossil fuel based power plants. And after these have all been replaced, replace the fission plants. We don't need to light the streets at night. Most street lights are badly designed, and most of the light goes up into the sky, being wasted for nothing. From the pictures of this one, it looks no different. Streetlights waste a light of light, thus energy and often illuminate the street badly. Right beneath it, you are basked in light so that you barely see what is happening

    • Re: (Score:3, Interesting)

      by blackest_k (761565)
      Its not too bad not suitable for every street admittedly.

      its look is like an anemone quite alien an almost Martian chronicles feel to it. googles bus shelter designs are not as interesting to look at.

      cost to make them may be quite high, however with 10% of European electricity production going into street lighting in europe the potential reduction in carbon emissions is significant.

      Retro fitting just the LED lamps to existing street lighting could be power saving in itself. The solar panels
    • Yeah but they normally don't glow in the dark.

      Well except the ones in chernobyl.. and those are killer zombie mutant trees anyway.

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