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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, whe
by pingswept 17y ago
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?
- skorgu 17y agoMy 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.
- graphene 17y agoThe difference is that the satellites' 230 W/m^2 is in a very narrow frequency band, and can thus be harvested and converted efficiently, where solar radiation is mainly at much higher frequencies, and, more importantly, spread out over a wide spectrum of frequencies. Our current best methods for converting these high-frecuency photons (solid state solar cells) only work well around a specific design frequency, and so they can convert only a limited part of the solar spectrum.