[ExI] Written for another list

[Eugen Leitl]

On Sun, Jul 29, 2012 at 12:51:16PM -0400, John Clark wrote:
> On Sun, Jul 29, 2012  Keith Henson <hkeithhenson at gmail.com> wrote:
> 
> > The energy payback from power satellites is short, two months
> 
> 
> I think that's a pretty useless figure because the problem is not the high
> cost of rocket fuel. In fact even if the launch cost to geosynchronous
> orbit were zero I'm not at all sure power satellites would be economically
> viable.  I think liquid fluoride thorium reactors are a much better bet and
> we already have the technology or nearly so, we've had most of it since the

We don't have the technology. If you don't believe me, try calling
Areva, and order one. Alternative fuelcycle breeders don't work
in reality yet. That's just as well, because we will need fissibles
for deep space.

> 1960's, and that is pretty amazing considering the tiny amount of money
> spent developing the concept.  About half a century ago we made a blunder
> and turned to solid fuel uranium reactors and not to liquid fuel thorium
> reactors and we've been paying a huge price for that mistake ever since.

Germany is at 25.1% renewable electricity (6 months 2012). 
Photovoltaics grew 47% relative to last year, and is at 5.3%
of total energy (breaking through to >50% of peak on good
days).

Few technologies can do that kind of scaling. Nuclear is not one of them.