How many SPSes for $87 billion ?

Thanks for the reply.

> wouldnt you think that some sorts of attacks you mentioned and some
> others you didnt mention do apply to nuclear power stations as well?

Yes, however, that is a good reason not to build build conventional
nuclear plants. Also, the fact that our current energy infrastructure
has a vulnerability does not mean we should design in such
vulnerabilities from centralization into a new proposal.

> But that will not get humankind out into space while a SPS is a
> valuable piece of space infra structure we do need not only to deliver
> energy to earth but to colonize space also.

I think there are other ways to get space habitats -- the best of which
I think is the seed idea designed by hobbyists and launched by
philanthropists. :-) But a government "make work" project or "aerospace
firm corporate welfare" is probably OK with me too (as long as the
results are made freely available). :-)

> On the other hand, It would be a good idea to restrict the power
> supply from SPSs to a given percentage because it is good not to
> become too dependent on it.

One issue here is that if the estimates pan out, and power from space is
again "too cheap to meter" like nuclear power was supposed to be, then
all other forms of energy production will be uneconomical. Of course, I
guess people could build up local fuel reserves (hydrogen or synthetic
liquid fuels) using cheap power to weather temporary embargos etc.
(though this is just a temporary solution to systemic failure).

Still, even if only 1/3 of power comes from space, it would be an
economic crisis to see it just shut off suddenly. Witness each oil
crisis from emebargos or price raises on just part of the oil supply.

I would prefer an energy system that is intrinsically secure (since this
thread is indirectly about spending money on energy security vs.
terrorizing Iraqis into submission because our oil is somehow under
their land :-) as opposed to an energy system that is intrinsicly
insecure and requires vast carefully managed networks and their related
(ultimately probably fascist) societies to secure inherently insecure
technical approaches against sabotage. Intrinsically secure energy
systems both reduce the need for generating power using insulation or
efficiency and they generate the power locally from renewable sources
whenever possible, making any extra external power needed occasionally
pretty much optional.

--Paul Fernhout