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Power Science Technology

MIT Envisions DIY Solar Cells Made From Grass Clippings 126

Zothecula writes "Research scientist Andreas Mershin has a dream to bring inexpensive solar power to the masses, especially those in developing countries. After years of research, he and his team at MIT's Center for Bits and Atoms, along with University of Tennessee biochemist Barry Bruce, have worked out a process that extracts functional photosynthetic molecules from common yard and agricultural waste. If all goes well, in a few years it should be possible to gather up a pile of grass clippings, mix it with a blend of cheap chemicals, paint it on your roof and begin producing electricity. Talk about redefining green power plants!"
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MIT Envisions DIY Solar Cells Made From Grass Clippings

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  • by elrous0 ( 869638 ) * on Monday February 06, 2012 @12:37PM (#38942929)

    in a few years it should be possible to gather up a pile of grass clippings, mix it with a blend of cheap chemicals, paint it on your roof and begin producing electricity.

    Just because it's "green" doesn't mean it's safe to let just any yahoo install an electric generator on his hut. Methinks it might be wise to let the village electrician do the installing.

  • Oh, please... (Score:5, Informative)

    by Jiro ( 131519 ) on Monday February 06, 2012 @01:00PM (#38943207)

    Yes, it takes grass clippings. Also "zinc oxide nanowires interspersed with titanium dioxide sponges".

    Claiming that this is a solar cell made from grass clippings is like the Rubik's cube solver built from Lego (one component of which was a computer; the computer's not built from Lego). If you want a car analogy, it's like claiming your car is made from glass (since it has glass in the windows).

  • MOAR. SQAR. METRES! (Score:3, Informative)

    by h4x354x0r ( 1367733 ) on Monday February 06, 2012 @01:00PM (#38943209)
    The continental US receives about 192,000 Exojoules of solar irradiance per year. We currently use about 91 Exojoules of energy from all sources. At .1% efficiency, and calculating extra for peak needs, intermittency, and transmission losses, we would have to cover nearly 100% of our continental land mass with this stuff to replace our current energy sources. Seems to me like smoking the other kind of grass really is a better deal.
  • Re:Efficency (Score:5, Informative)

    by wagnerrp ( 1305589 ) on Monday February 06, 2012 @01:08PM (#38943323)

    Of course in Star Trek miracle land, you'd have 47% efficient cells thus generating about 40 KW. I donno what I'd do with 40 KW laying around

    Sell it back into the power grid for use in high density apartment buildings, and higher density manufacturing industry.

  • by ArsonSmith ( 13997 ) on Monday February 06, 2012 @01:12PM (#38943379) Journal

    They figure with $30-40 million in government grants they may be able to double that.

  • by Oligonicella ( 659917 ) on Monday February 06, 2012 @01:57PM (#38943967)
    "It is only a matter of improving efficiency."

    No, it's not. It's a matter of how much the efficiency can be improved. In no way will this ever become a realistic electrical source. By its very nature it cannot produce enough.

    "If this material is so cheap, it can be used as a paint to reduce electricity requirements by 5%."

    No, that presumes you can stack paint. You can't. It's the area that counts, not how much paint you have.

    As figured out by someone elsewhere on this topic, an entire house roof will light one dim bulb for a day. I seriously doubt this even approaches 5% of your use.
  • "Photosynthesis in plants only operates at a couple percent efficiency in the first place."

    WRONG!!! Try 9% under regular sunlight, and ~15% under LED lighting.

    Oh, did I neglect to mention photobiology/optoelectronic R&D is my job?

  • Re:Efficency (Score:5, Informative)

    by Dan East ( 318230 ) on Monday February 06, 2012 @02:26PM (#38944293) Journal

    That is somewhat more than the naysayers claim (barely enough to run a watch, etc) but is not enough to be useful.

    Sorry, but you're off by several orders of magnitude. A wrist watch consumes microwatts of power - around 1 micro watt (Slashdot seems to strip the micro symbol). Thus 40 watts is enough to power 4 million wristwatches.

    Seiko makes a watch with an IC powered by only 25 nano watts of power!

  • by feedayeen ( 1322473 ) on Monday February 06, 2012 @02:56PM (#38944647)

    Ignoring the fact that there's no such thing as "regular sunlight" due to variances in season/geography: LED lights can come in any of an enormous variety of spectra, be combined, or not even be a single wavelength at all and be an ultraviolet light with an LED UV emitter (white LEDs). What meaningless numbers and broad statements...

    Translations since you want to be an obnoxious dick.

    "Regular Sunlight" - The spectrum of light emitted by the sun which makes it though to the surface under normal atmospheric conditions consisting of a distribution of all wavelengths within the visible spectrum along with limited radiation outside this range which have near negligible effect on photosynthesis.

    "LED lighting" - Controlled, artificial lighting used in laboratories which have been designed to produce a desired light spectrum. This is used to produce the ideal lighting conditions with the highest achievable efficiency (most likely a combination of red and violet LEDs).

    "Efficiency" - The ratio of energy put into a system to the ratio of energy put out

  • by radtea ( 464814 ) on Monday February 06, 2012 @03:36PM (#38945225)

    WRONG!!! Try 9% under regular sunlight, and ~15% under LED lighting.

    The GP is correct for the typical case of real plants: http://en.wikipedia.org/wiki/Photosynthetic_efficiency [wikipedia.org]

    The typical case is pretty low efficiency, the best case (sugarcane) is lower than your 9% number.

    Oh, and did I neglect to mention your .sig is obnoxious? I'm guessing you're an undergrad with a bottle-washing role.

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