On May 14, 2011, at 6:40 AM, Isaac Marino Bavaresco wrote:

> I couldn't find figures for the energy necessary to electrolyze water,
> but I bet it is the same 286 kJ/mol of the H2+O2 combustion.

I remember reading somewhere that Electrolysis of water is pretty =20
inefficient.  That is, you have to be in significantly more electrical =20
energy than what you'd calculate is needed to separate the atoms based =20
on the "pure chemistry."  It would be "exciting" to discover a =20
mechanism to improve that efficiency, even without coming anywhere =20
near breaking unity and lighting up fraud detectors.

There has been work in this are; TI was involved in a Solar-to-=20
hydrogen project back in the early 80s (IEEE TRANSACTIONS ON =20
COMPONENTS, HYBRIDS, AND MANUFACTURING TECHNOLOGY, VOL. CHMT-5, NO. 4, =20
DECEMBER 1982: Development of the Spherical Silicon Solar Cell) and =20
"Artificial Photosynthesis has been in the news as recently as this =20
month.

(Driving across the US deserts between Los Angeles and Denver (100s of =20
miles of highway with essentially nothing on either side), I was =20
struck by the thought that what we need is a big tractor-crawler thing =20
that eats dirt and poops solar converters (even rather inefficient =20
ones.)  We could stop thinking of "Solar farms" as big square areas, =20
and start thinking of them a long narrow strips that parallel existing =20
infrastructure (roads, power lines, etc)  Just pipe/wire the results =20
along the roads to fuel/charging stations and use it "immediately" for =20
the long-distance shipping traffic.  And then I was struck by thinking =20
about maintenance issues and got discouraged.)

BillW

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