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Solar's Giant leap

Discussion in 'Energy, Environment, and Policy' started by vfx, Aug 4, 2008.

  1. vfx

    vfx Well-Known Member

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    #1 vfx, Aug 4, 2008
    Last edited: Aug 6, 2008
    This sounds way too good to be true.

    'Major discovery' from MIT primed to unleash solar revolution - MIT News Office

    But I give it cred because of the source.

    Quote:
    "MIT researchers have hit upon a simple, inexpensive, highly efficient process for storing solar energy.Requiring nothing but abundant, non-toxic natural materials, this discovery could unlock the most potent, carbon-free energy source of all: the sun."

    Should we give them a coupla' billion to speed thing up?
     
  2. Cobos

    Cobos S60 owner since 2013

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    In the short writeup that is explained I see one problem. The Pt catalyst used to split H2 from water. Pt is too expensive, especially for use in a system that will have mass appeal. They need a much cheaper material if this should work.
    Very interesting research regardless...

    Cobos
     
  3. malcolm

    malcolm Active Member

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    I appreciate that the "splitting" part may be more efficient than present-day electrolyzers, but there's the efficient bulk storage and efficient recombination sides to the problem as well. Batteries and inverters are tough to beat.
     
  4. TEG

    TEG TMC Moderator

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    Platinum is sounding like the "green metal". Used extensively in catalytic converters to clean up exhaust, and now to extract hydrogen from water. Too bad it is so expensive.
     
  5. SteveF

    SteveF Member

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    I'm no expert, but if as the article describes, during the day their system allows the "efficient' production of hydrogen and oxygen (and assuming as you say they find an efficient way to store these gases), isn't it a straightforward process to use the stored gases to run a fuel cell and thereby produce energy for nightime use?
     
  6. Chris H.

    Chris H. Member

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    In classroom demonstrations of electrolysis of water a little salt (sodium chloride) or H2SO4 (sulphuric acid) is added to the water to make the process more efficient (and faster). The electrodes are often platinum, but they don't have to be. Stainless steel electrodes also work well.

    Electrolysis - Wikipedia, the free encyclopedia

    I think Malcolm hit the relevant points when he mentioned the storage issues with the O2 and H2. To store them at ambient pressure requires large containers; to compress them requires an input of energy, thereby reducing efficiency still further.
    When the gases are recombined to extract the stored energy, a fuel cell will be required. Fuel cells are neither cheap nor simple. Unless the cost of fuel cells drops dramatically, I don't see how they would be a better option than batteries.

    The article, and the accompanying video clip, seem to suggest that currently there is no way to store solar energy for later use. I think that we know that this is untrue.

    Lastly, plants do not store energy in the manner described. Plants store solar energy in the form of simple sugars (glucose, fructose, & sucrose). Photosynthesis can be described chemically as follows:

    6 CO2(g) + 12 H2O(l) + photonsC6H12O6(aq) + 6 O2(g) + 6 H2O(l)

    carbon dioxide + water + light energy → glucose + oxygen + water

    It is possible that the researchers at MIT are using the enzymes from the Photosystem II pathway:

    Photodissociation - Wikipedia, the free encyclopedia

    I had posted on the Tesla Founders blog several months ago (March 27th @ 1:47pm, "Focus Green") that I had some ideas related to energy harvesting and storage using biological systems, although I didn't elaborate at the time, I was thinking specifically of the electron transport chain in photosynthesis (which includes PS II). Anyway...
     
  7. Chris H.

    Chris H. Member

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    Also, remember that PEM (proton exchange membrane) fuel cells are only about 30-50% efficient. Combine that with the (in)efficency of electrolysis, and you end up with a pretty inefficient system overall. Some pumped water systems are more efficient...
     
  8. SteveF

    SteveF Member

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    Thanks for furthering my education on this topic, Chris.
     
  9. Cobos

    Cobos S60 owner since 2013

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    Chris: This might make sense for a house size cheap system to store solar energy though if you can get huge gastanks with low compression. I'm thinking that's easier to maintain than a water pump system and turbine for 1-2 households.

    Cobos
     
  10. SteveF

    SteveF Member

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    Another voice in support of all-electric vehicles

    The CEO of Nanosolar, Martin Roscheisen, has recently contributed a few words in support of electric vehicles: "...it is clear that if the goal is to maximize energy efficiency, the end point to go after is all-electric cars everywhere. Moving all of transportation to all-electric would essentially cut in half our overall energy consumption while delivering the same distance."

    Here's the link to "Going All-Electric": Nanosolar Blog

    Maybe some day there will be enough voices to drown out the oil-company shills who continue to knock electric vehicles.
     
  11. vfx

    vfx Well-Known Member

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