[ExI] pentagon wants orbiting solar power stations

[Eugen Leitl]

On Tue, Oct 16, 2007 at 01:16:57PM -0700, hkhenson wrote:

> >Why can't all cars and light trucks be electric?
> 
> It's the same reasons we are having so many problems with trying to 
> design and build electric cars now.  But you mentioned 

In principle modern cars could be self-guiding, so a PV
electrified rail along the highway would work. As a bonus, no
more traffic contention.

> "trucks."  Every calculated how much energy it takes for a big truck 
> to go over the passes in California?  The key to hydrocarbons is they 

The advantage of electric (and hybrid) drives so that you can
regenerate large fraction of the energy in such and similiar
(stop-and-go traffic) cases.

> are energy dense and 65% of the mass of the products comes from 
> sucking in air.  Refueling an automobile from a gas pump is (from 

Methanol has only half the energy density of diesel, is low on
carbon and rich in hydrogen and the other electrode in fuel cells
is also air. The raw efficiency is 2-3 times that of an ICE,
even without lightweight structures, regenerative braking and smaller
engine and a spike cache.

> memory) 20 MWs thermal.  I.e., if you just burned the gas coming out 
> of the pump, the flame would be 20 MW.  (For comparison, a large line 
> locomotive at full power might produce 3 MW.)

Very large trucks and newer naval carriers are hybrid. It's only a
question of time before fuel cells will force out the ICE and the
gas turbines.
 
> >And why wouldn't a  substantial decrease in oil burned help?
> 
> Because you are not going to get it.  Any savings the US might manage 
> are going to be sucked up other places in the world.  We have to 

We're going to start saving anyway, because Peak Oil scenario seems
to turn out true. It's probably not smart to go nuclear exchange over
resources. Nobody's going to win that one.

> displace oil and coal with something better.  Nuclear power is a 
> relatively short term solution (limited supplies of uranium) and has 

Thorium is quite a bit better, but I don't like nuclear power for
terrestrial applications. People can't handle radioisotopes, and
every mole of free neutrons only aids proliferation.

> really horrible risks.  If there were no other choice, I would 
> reluctantly support it.  It may turn out there is no other choice if 
> there is some engineering/physical reason we can't build SPS.

As far as I can see the first issue is launch costs, and use
of extraterrestrial resources.
 
> Keith Henson
> 
> PS, one alternative to abundant energy is some combination of war, 
> starvation and disease that cuts the population back.  Oil supplies 
> would last a lot longer if there were far fewer people. 

Ever the optimist, eh.

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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