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by austinz 4436 days ago
It's not a given that rectification/conversion losses are necessarily greater than, less than, or equal to the gain in base output. A lot of whether that is true depends on how much solid state power electronics improve over the coming decades.

In terms of the cost of putting materials into space, isn't that the exact problem SpaceX is trying to solve? Right now, it would be economic folly to build one of these things. In decades or centuries, when we have moon colonies and/or asteroid mining and can do all the large-scale fabrication in situ, SSP could very well be significantly cheaper than other forms of power generation.
1 comments
Tloewald 4436 days ago
Assuming you wave a magic wand and get rid of the technical and cost issues, you then run into thermal pollution. You're collecting heat from space and beaming it to Earth and then inefficiently converting it to electricity.
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austinz 4436 days ago
According to [1], the surface of Earth receives 89,300 terawatts of power from the Sun on average. According to the stats at [2], world power consumption in 2008 was ~17 TW. So even if we could somehow build the tens of thousands of these power plants necessary to completely supply the Earth's power needs, and assuming that none of the consumed power ended up being radiated back into space, we would only be affecting the Earth's energy budget by 0.02%.

[1] http://www.sandia.gov/~jytsao/Solar%20FAQs.pdf

[2] http://en.wikipedia.org/wiki/World_energy_consumption

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Tloewald 4435 days ago
So with a magic wand and an incredible amount of money we'll only make the problem slightly worse.

And it's not clear how slightly -- climate change is being caused by accumulation of greenhouse gases during a period of reduced solar output (cyclical fluctuation of 0.1%). BTW 0.02% seems like a lot more when compared to the sun's cyclical variation of 0.1% (which has measurable effects) and suspected historical variations of perhaps 3% that caused ice ages.

http://en.wikipedia.org/wiki/Solar_variation

http://science.nasa.gov/science-news/science-at-nasa/2013/08...

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austinz 4434 days ago
0.02%, if you are building a hypothetical network of power plants with the same total surface area as the state of Maryland in orbit.
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