Zubrin Article - Energy Independence

Zubrin's branching out, huh? Energy is certainly the "issue of the day"
- and given Zubrin's previous written stance against space solar power,
I'm not surprised it garners absolutely no mention in this article -
very disappointed, but not surprised.

Zubrin is right that hydrogen doesn't help, but Zubrin is quite wrong
that biomass ethanol/methanol is the solution:

* Liquid fuels are not essential to transportation: see notes here:
http://www.altenergyaction.org/mambo/index.php?option=com_content&task=view&id&Itemid=2
on "Electrification of Transportation"

* On a large scale, it is very hard to see whether ethanol production
under US conditions actually produces any net energy. David Pimentel of
the Cornell Ag School has done a lot of detailed calculations on this
indicating ethanol (from corn) is net energy negative. You can get net
energy out of biomass (the energy comes from the sun of course), but the
best way is to grow it and burn it directly (and in place) to make
electricity. See:
http://www.altenergyaction.org/mambo/index.php?option=com_content&task=view&id=69&Itemid=2

Recent arguments about this rely on the energy content of side uses of
the corn, as animal feed for instance, which can make corn to ethanol
net energy positive - but those side markets don't exist at the vast
scale that would be needed to meet US transportation needs.

* Even with the best numbers on net energy from biomass, you need to
plant it on a vast scale to actually meet that demand, because those
best numbers are well under 1% efficiency of sunlight to chemical
energy, and seasonal to boot. Total world primary productivity of the
biosphere is about 4000 quadrillion btu (quads)/year; human primary
energy use is about 400 quads/year, almost all of which is coal, oil or
natural gas. So in principle there's enough energy in the biosphere to
meet our current demands; we just have to divert 1/10th of everything
that grows on land or in the oceans. And double that two or three times
over the next century as demand continues to rise. Hmmm, not much margin
for error or losses (like conversion of raw plant materials to ethanol)
in there...

Pimentel's comment was that even with the best numbers for ethanol
production, you would have to convert an area larger than the contiguous
48 states completely over to growing corn, in order to just meet US
demand for transportation fuel.

See:
http://www.altenergyaction.org/mambo/index.php?option=com_content&task=view&id&Itemid=31
on world energy numbers...

The ironic thing is that the argument against new technologies, like
gas-electric hybrids, or in other places against solar, wind, etc. is
that they have such a small scale currently they "can't possibly" grow
to meet demand. But the REAL scalability problem is on the other end,
with existing technologies that are basically at their limits. We NEED
the new technologies to replace what we've got now, and we need heavy
R&D in them to get them cost effective, and then they'll naturally grow
at the needed pace. And space solar power absolutely should be one of
those new options seriously on the table.

Arthur