

Will the stars align for space-based solar power? - jballanc
http://arstechnica.com/science/news/2009/07/will-the-stars-align-for-space-based-solar-power.ars

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pingswept
This does not look promising. Powersat suggests that they will be transmitting
energy back to the earth at an areal density of less than 230 W/m^2. The sun,
when it's shining, is around 1300 W/m^2. With night, clouds, atmosphere, and
the like, the average available energy is in the range of 100-200 W/m^2--
similar, but free.

Given that we already have the sun providing us with radiation, why spend the
money to build a second one?

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skorgu
My non-expert understanding is that the efficiencies come out better in the
big picture despite adding a conversion step. You can get maximum sun time in
space for the solar component and have a very cheap and very efficient
rectenna on the ground that isn't much affected by atmospheric losses.

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billswift
Also the microwaves can be converted into electricity more efficiently than
sunlight can.

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skorgu
Right. Rectennas ought to be able to get vastly higher efficiency numbers
(Wackypedia claims 90% but its un-cited) than solar panels (~40%, again
Wikipedia).

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onreact-com
While this is good news I still believe that current projects to get solar
energy from sunny areas in deserts like the Sahara are more feasible.

