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Havesting the suns energy

  1. Jan 2, 2013 #1
    Not sure if this belongs here but if not, please move it to the correct section.

    Basically, why can't we harvest more of the suns energy? Could we not launch thousands of mirrors over a period of time and have them reflect the energy to a single collection point? Aside from potentially unlimited energy on earth. What else would be possible if we could harness 100% of the suns energy?
    Last edited: Jan 2, 2013
  2. jcsd
  3. Jan 2, 2013 #2


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    Directing more of the solar output onto Earth could have significant effects on our climate. There have been proposals for space based solar power but there are many limitations and compared to ground based methods the EROI (energy return on investment) is not good enough. It's hardly necessary to try and tap more of solar output considering the entire of human civilisation uses less than a tenth of a percent of the energy Earth catches.
  4. Jan 2, 2013 #3
    Well seeing as we require energy for interstella space travel, imagine having 90% of the energy the sun emmits everyday collected up into some kind of storage to power a spaceship to incredible speeds?

    I read somewhere that with that kind of energy, it could also be possible to warp space time itself.
  5. Jan 2, 2013 #4


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    90% of the Sun's output in a day is 3e31 joules. A weeks worth of collection would be enough to break apart the entire Earth so that nothing was left. That's not the type of energy you can store.

    For more practical speculation on something similar you might want to look into beamed spacecraft propulsion.
    This is based on some esoteric calculations about how much energy warp bubbles would take to make and sustain. IIRC to transport a few molecules across the galaxy would take several stars worth of mass energy equivalence. Note that this doesn't mean warp bubbles are possible, as I understand it they would still need exotic matter that we have no reason to believe exists.
  6. Jan 2, 2013 #5
    The most distinguishing feature of solar energy is that it is already distributed, for the most part. Any system based on regional massive central collection and redistribution defeats the advantage of it already being distributed, especially if it is just converted to AC and treated like another utility with transportation losses.

    The whole beauty and dream of solar is collecting it locally at the place of use, straight DC to appliances and battery storage, one time sunk cost of installation with periodic cost of maintenance.

    Remember when the nuclear power industry promised it would be so cheap that they would not even put a meter at your home? Central collection of solar will make and break that same promise... we can all have solar panels on the roof when and if the cost is right.
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