[ExI] Bosch exits Solar business in Germany

[spike]

>...] On Behalf Of Eugen Leitl
>...
 
>>... My notion is that we must build the nukes, build the windmills, build 
> the rooftop PV installations, and get with it on my own favorites, the 
> space based solar and massive wind and solar powered coal to liquids 
> and coal to fertilizer operations, located in the American 
> southwestern desert, Mexico, the Sahara, the Gobi.

>...Coasts are natural locations for seawater desalination.

>...http://www.bloomberg.com/news/2013-01-01/california-desalination-financi
ng-closes-on-1-billion-project.html

>...If graphene membranes can be made to work desalination will be even
low-energy. Don't ask me about the pumps and the pipelines, though, that
looks expensive. Inland transport will be hence limited. Capture from air
only gives you very little, and makes it even harder for folks downwind.
Eugen
_______________________________________________

Pipes definitely, pumps maybe not.  Follow please:

Reverse osmosis from seawater to drinkable fresh usually requires about 40
bars pressure differential, so if you have a pipe going down to a depth of
about 400 meters, there should be a constant supply of fresh water at the
bottom of the pipe, ja?  The pipe need not be vertical, it can  follow along
down resting on the sea bottom down off the continental shelf out into the
deep water, or drop down in an undersea deep spot such as that found in the
Monterey Canyon off the California coast, where the waters reach down to
about 3600 meters.

So imagine your pipe terminating at 400 meters, fresh water constantly
appearing down there as you pump it out to use it inland.  Imagine now you
drop the end of your pipe down another 100 meters.  You would expect the
fresh water to appear in arbitrary quantities at a depth of about 100 meters
inside the pipe, ja?  Nein, for fresh water is about 3 % less dense than sea
water, so the depth of the water in the pipe is now about 103 meters, or
about 397 meters from the surface.  If you keep dropping your osmotic
filter, the fresh water level in the pipe keeps rising, about three meters
for every 100 meters depth of the filter end.  So if the filter end is about
13 km below the surface, the fresh water is all the way back up to the sea
surface, available in arbitrary quantities to pump inland.  But oh dear, 13
km is a long ways down.

Now assume we find some kind of magic material which can separate fresh
water from sea water at the natural osmotic pressure of about 27 bars.  Now
fresh water appears at a depth of only about 270 meters, and the fresh water
meets the surface when the filter is about 9 km down, which is about twice
the average depth of the ocean, but not as deep as the deepest trenches in
the seas, some of which go down nearly 12 km.  If we had a sufficiently long
pipe to place an osmotic filter at the bottom of the Mariana Trench, the
fresh water in the pipe would rise above the sea surface about 100 meters.
>From that height, the water could flow inland by gravity, with no pumps
needed.

Of course if the claims regarding graphene membrane desalination are true,
then we need not go to all the theatrics of a pipe reaching the bottom of
the Mariana Trench.  A graphene membrane osmotic filter a mere 40 meters
below the surface would begin to supply fresh water, and a pipe a manageable
1300 meters below the surface would suffice to supply fresh water at sea
level.  Such a filter down to the bottom of the Monterey Canyon a mere 120
km off the California coast would result in an arbitrary supply of fresh
water at a pressure of 70 meters of water, or about 7 atmospheres, elegantly
sufficient to let water flow anywhere in the state or to the desert
southwest completely by gravity, using only lots of pipe.

That being said, I do firmly believe the suggestions of seawater osmosis to
fresh water at a pressure differential well below the natural NaCl osmotic
pressure are mistaken, wildly exaggerated or delusionally optimistic.  If on
the other hand I am mistaken or delusionally pessimistic, if osmosis can be
made to somehow operate at a fraction of the natural osmotic pressure of
seawater to fresh water apparently in violation of physical law as I
understand it, I am most eager to see us undertake the task of building this
astonishing pipeline system.  We know how to do pipes.

spike