[extropy-chat] [Bulk] Re: [Bulk] Re: Forbes Magazine on Robotics

[Keith Henson]

At 09:07 AM 8/22/2006 +0200, you wrote:
>On Mon, Aug 21, 2006 at 10:23:51PM -0400, Keith Henson wrote:
>
> > Relative to earth, space is benign.  I would expect a power satellite to
> > sit in orbit with little maintenance for decades
>
>Current PV arrays are already warranted for 20-25 years weathering,
>and they don't require to be launched, and produce power where it's
>consumed. PV is already economic off the grid, and will probably
>break-even with fossil within a decade, depending on how robust
>nonrenewable energy price development is.

Do you go to bed when the sun goes down?

> > > > I think you are not including the rapid increase in China's 
> consumption.
> > >
> > >No, those predictions include the growth of China's and India's 
> populations.
> >
> > Consumption is growing much faster than population.
>
>I agree that China alone is going to get quite problematic, what little
>I know of the problem set there from a few pages from Diamond's "Collapse".
>
> > >Switching to renewable energy,
> >
> > Satellite solar power is renewable and offers the prospect that it will be
> > *much* less expensive than current or projected sources.
>
>I agree that a launch cost drop to LEO by an order of magnitude would
>make solar satellite power cost-effective.

Not at all.  Even two orders of magnitude is no where near 
enough.  Besides, you don't want to reduce cost to LEO, you want to reduce 
it to GEO.

>But launch costs are far more
>unyielding

That's the point of a mechanical (moving cable) space elevator.  Once built 
up to a mature size, it is lifting 2000 metric tons per day and using a Gw 
of power.  In 5 days it puts up 10,000 tons, which is enough for a 5 Gw (at 
the ground) power sat.  So a power sat pays back the energy used to lift it 
to orbit in *one day*.  To put it in monetary terms, a Gw hour lifts about 
a hundred tons.   At ten cent/kwh that's a million dollars to lift 200,000 
pounds or $5 a pound.  Once you get the first few on line, I can't see 
power being rated at more than a cent/kwh, which means 50 cents a pound to 
GEO . . . . and falling.

At some point you start building stuff our of asteroid materials just to 
avoid shipping on earth's surface!

>than new PV technologies to reduce PV price by an order of
>magnitude (less, IIRC 2-3x would do). Installation costs are not relevant
>for new stuctures, designed around energy production by double duty.
>
> > You might consider that I have been in this business for over 30 years
> > now.  Had we done power sats starting back then, the US would be a major
> > energy exporter and we have no reason to be concerned about oil producers.
>
>The economics of it doesn't work even now, and it would have looked
>even worse 30 years ago.

The economics were fine.  See the article in Science written by O'Neill and 
vetted by half a dozen economists.  The problem was that the overall chain 
of complexity of mining the moon for materials, launching them off the 
moon, refining them in orbit to what you needed and then building the power 
sats was more than investors could cope with.  The payback time was a bit 
long, and the business went through a fair amount of money (some small 
fraction of what the Iraq war has cost) before it made money hand over fist.

> > We didn't.  We are not likely to do anything useful about the energy
> > problems unless someone can see huge profits to be made.
>
>Efficient burners (recently, pellet burners), house insulation,
>efficient light ICEs, thermal and PV solar and wind is doing very
>well here. If you remove the fossil volatility by a tax ratchet the
>market will do the rest quite efficiently, starting with the
>small end, but eventually arriving at the top end (solar power
>satellites).

So we are seeing a year to year drop in energy use and cost?  I think you 
have a bit of misunderstanding on this topic unless you have a pellet stove 
and are off the grid.  Most people currently live where such things are 
outright impossible.  If you do live such a place, you may have some idea 
of how much of your time is eaten by maintaining the stuff you need to live.

All these things help, but not enough in the long run, not if you have any 
desire to live in style.

Keith Henson