Nuke vs. SPS ( Population reduction isn't necessary for wilderness)

--- In spacesettlers@yahoogroups.com, "sailor.barsoom" wrote:
> --- In spacesettlers, "hitssquad" wrote:
> > Energy from space (to Earth) isn't realistic, given the presence of cheaper alternatives.
> a) it's so expensive to launch anything into space,

A dirty secret of SPS is that its cost varies minimally with launch cost. Assume launch cost is $100/kg, and show us on paper a plan for building SPS in GEO at an overnight cost of less than a quadrillion dollars per gigawatt.

> c) the alternatives are are not priced according to their full cost

Is that falsifiable, and do you have a plan for changing that even if it were true?

> gasoline

Energy from space is electricity.

> d) the alternatives are subsidized while space solar power is not.

Is that falsifiable, and do you have a plan for changing that even if it were true?

> dense arcologies, maybe.

No. Just cities.

> > Also realistic would be 100 trillion on Earth, and another 100 trillion on Venus.
> calling this "realistic" while saying that power from space solar is not, is pretty silly.

It doesn't suffer from the tidal-force problem, while Earth-orbit-SPS does. Also, all of the technologies needed for the former already exist. No one knows how many-kilometers-wide structures in GEO would deal with the tidal forces, because, so far, no one has bothered investigating it even via mere computer simulations. Another dirty secret of SPS is that it isn't subject to economies of scale. A principal reason for that is the tidal-force problem (a problem not encountered at my suggested SPS locations of Sun-Earth L1 and Sun-Venus L1, by the way).

The only real-world-proven figure we have, so far, for the cost of SPS is a quadrillion dollars per gigawatt (and that's in LEO with no downlink and of a small-enough size as to be unaffected by tidal forces), which doesn't work out to competitively priced electrical service. If the cost of the capital were 10% per year, that would be 100 trillion dollars spread over ~8,700 hours * a gigawatt =
$100 trillion / 8.7 billion kWh = $11,494 per kWh.

That isn't competitive against even the most expensive nuclear electricity ever marketed.