[ExI] Obama Transition Team Examining Space Solar Power

Keith Henson hkeithhenson at gmail.com
Mon Dec 22 00:53:58 UTC 2008

On Sat, Dec 20, 2008 at 8:30 PM, Kevin H <kevin.l.holmes at gmail.com> wrote:

> Yeah, I was excited to see this.  One of the commenters on Slashdot linked
> to this article by the Economist giving a rather sobering account of the
> economics of space solar
> power: http://www.economist.com/science/tq/displaystory.cfm?story_id=12673299
> It seems like *someone* in the transition team has looked at this, but no
> indication if a serious look has been given to it or not.  I added to
> Keith's wiki my question about opportunity cost: whether the same money for
> space solar power we might be better off instead investing in terrestrial
> sources of power.  While it true that space satellites would be able
> to receive five times as much solar energy as on the earth, would it be
> cheaper just to produce five times as many solar panels on the earth with
> the same amount of money?  Or investing in wind farms or nuclear power
> plants?
> Kevin

Dr. David MacKay (top of the list when you Google his name) has a good
work on the problems of trying to collect renewable energy on earth.

it largely depends on the cost to lift power sat parts to GEO.  The
advantages are not just in the power multiple, but in the fact that
the energy is steady, no clouds, no wind stopping, i.e. no storage.
The other advantage is that you don't have to build massive and very
expensive lines from the southwest to the mid west and east.  You just
plunk a rectenna down close to the load.

If you can haul the parts up on a space elevator, there is no question
that power sats are the less expensive approach.  If you have to haul
the parts up on rockets, it's marginal.  The hybrid methods of using
rockets to suborbital and lasers to kick the payload into GEO meets
the penny a kWh requirement.  Of course the old method of developing
extraterrestrial materials works best of all, but there is not enough
time to develop space industry.  It's not entirely obvious that any
long term energy solution is needed.  If I were confident the
singularly would get here before famines and resource wars I wouldn't
worry about it.  But I can't put a firm date on either.  The
consequences of running out of energy are really dire.  Some models
show the population dropping a hundred million a year, bottoming out
at 1-2 billion.


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