[FoRK] Malthusian machinations
eugen at leitl.org
Thu Jun 17 07:49:14 PDT 2010
On Thu, Jun 17, 2010 at 09:11:48AM -0500, Jeff Bone wrote:
> All good points, let me just address one:
> On Jun 17, 2010, at 8:01 AM, Eugen Leitl wrote:
> >> Municipalities don't build and launch your orbital harvest facilities
> > Why do they need to do that?
> First, you were the one that suggested the need for those things, not me. ;-)
I did no such thing. I merely pointed out that
not only is there a considerable leeway (the abovementioned
10^5 flux excess versus our usage) but that we're not
limited to the insolation captured by Earth in principle.
The sky's not the limit. Literally. There are no clouds in LEO.
And there's always an insolated point whenever you look
up into the night sky. People forget that diurnal cycles
are a very local phenomenon. And supergrids can reach
from coast to coast, and across seas. So can hydrogen pipelines.
But that is irrelevant for today. We care about today.
You do not have to look very far to see what we can do today.
Or within a half century.
> Second, cf. the e-m about the problem w/ solar harvest at the
> municipal level in dense urbs. All ears if you have thoughts about that...
Empirically, it is easy to see how suburbia density could
be net exporting even under rain cover and drizzle. I just
said "rain cover and drizzle", yes.
This doesn't mean that this is *currently* economical, or that
you can add this to existing systems and people without changes
in systems or attitudes of their operators. But, empirically,
it's feasible. It's been done.
Anyone is having trouble swallowing this? Anyone? Bueller?
Now just outer building skin, using today's efficiencies is a
pretty harsh acid test. Consider the so-called sealed land area,
which is area covered by human structures. In Germany, the
area is about 6%. (The total insolation upon Germany is
about a factor of 100 in excess of its total energy need). If you
just look at electricity, and want to cover that exclusively
via today's PV, you're looking at one tenth (12%) of the area we already
use. Read my lips: extra zero land. One tenth of what we
already covered is enough. Just with today's PV. Of course
Germany is much more densely populated than most other
industrialized countries. Of course it is possible to further
reduce energy use by increasing efficiency. Of course further
efficiencies will go up. Etc.
So in general, you can supply the cities with a small bulge
of PV systems surrounding them. Consider suburbia a source of
energy, and not a sink. Plant stuff underneath or graze
Crunch the numbers for other countries. I can't see why it
wouldn't check out. Even for the Netherlands. Or Japan.
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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