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Solar Power Satellites


NGTOne

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So, while it didn't make economic sense in the past, at some point in the future it may be the only way forward. Or maybe they will get fusion working before then.

This.

I read an analysis from the '80s which, while hopelessly optimistic in a number of ways, predicted that fusion and space solar would both form important parts of the US (it was American-centric) baseload generating mix by the mid-21st century (and they reached this conclusion without knowing the outcome of the CO2 generation controversy - coal was a large part of that portfolio as well. Knowing what we do today about pollutants and whatnot, I can only expect the fraction provided by these "future tech" power sources to increase).

Commercial fusion is, according to the current roadmap and barring revolutionary breakthroughs, AT LEAST 30 years away, and that's only for the first plant (appropriately called DEMO). Widespread use of fusion for power generation will probably take until at least the 2050s-2070s, if not later. All the technologies required for space-based solar generation have been demonstrated (though, admittedly, not at the scales required) - the only thing lacking is funding and willpower.

Edited by NGTOne
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Remember that the costs of orbital solar are mostly upfront or constant. That is, you pay a fortune to construct and launch it in the first place, and once its up there maintenance costs and so on are ongoing, but actually generating power with it is cheap.

Having no fuel costs and having no ongoing costs aren't the same thing. If they were current renewables such as wind would have the same advantage, and would be savagely undercutting anybody having to pay for fuel. In reality that's not the case.

Nobody pays for anything as big as a power plant up front, it's all financed. Big investors want to see a continuing return on their investment (discount rate is one of the make-or-break figures for new project). Huge capital costs mean the operator makes huge regular repayments to whoever stumped up the cash in the first place. That means the operator does need to be selling the juice at a high enough price to cover the cost of the financing.

You can compare the various types of power generating technologies by evaluating their lifecycle cost in terms of price per kWh. One resource I found online rated satellite solar power as costing an eye-watering $26.15kWh-1 (at 5% over 40 years). So that's about a factor of 100 above what's economically viable, even to sell at peak hours. To meet base load you'd need to be more like $0.05kWh-1 or less.

In my opinion there's absolutely no way this technology is viable while we're stuck using rockets to lift mass to orbit. We would need plentiful cheap space elevator capacity for it to be viable. If costs to GEO nosedived to $100kg-1 it'd be all on.

Oil prices are rising, the political issues around nuclear are getting worse if anything. Environmental restrictions are getting tighter, which will raise the cost of running fossil fuel plants. And the third world is going to start burning fuel in a big way at some point.

Indeed, renewables are going to become increasingly important. Here in the UK the restrictions on fossil fuel plants have already meant that most of the older plants have already shut down, are running on severely reduced hours, or are converting to co-firing biomass. But none of this argument specifically makes a case for power sats, just for renewables in general.

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The way the U.S electric system works is when everybody desperately starts running out of power you build a new power plant, otherwise you don't make any money. Nobody with money is going to risk a huge investment in solar power unless the world is 100% going to run out of power in like a year. Otherwise its just not economically feasible. No politician is going to risk there terms in office for something years in the future. So unless there's a world war about to start over energy resources its probably not going to happen, and even then war is more likely.

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