[ExI] gravel batteries

spike spike66 at att.net
Thu Apr 29 19:00:18 UTC 2010


> ...On Behalf Of Adrian Tymes
> Subject: Re: [ExI] gravel batteries
> > ...
> > The argon is then fed into the second silo where it returns 
> to normal 
> > atmospheric pressure, initiating a cooling effect that 
> chills the gas 
> > and rock to -256 degrees...
> Alternately, just take two large lake basins - possibly 
> artificial - one lower than the other.  When you have energy, 
> pump from lower to higher.  When you need energy, drain from 
> higher to lower and use the flow to spin turbines.  Might be 
> even cheaper, unless you get protesters worried about the 
> environmental results of moving that much dihydrogen monoxide around.

Ja, and I can assure you that storing energy as potential in water of
different heights is waaaay more efficient than storing it as a temperature
difference between two reservoirs.  If one is going to invest in building
silos, the energy can be extracted relatively efficiently with water
pressure differential.

A couple things I saw wrong with the idea of the argon silos: argon is
expensive and unnecessary for this application.  It is chemically neutral,
but so is nitrogen for this kind of application, and air is 80% nitrogen,
close enough to use that stuff instead.  Far cheaper it is than argon.
Actually one could use helium for this purpose, as it would store more
energy per unit energy used to compress the gas.  However, read on.

Yes we could store energy by creating a huge warm reservoir and a huge cold
reservoir, but extracting the energy and turning it back into electrical
power is appalling in its inefficiency with that technique.  On the other
hand, the scheme can be used anyway if one can find an industrial use for
warm water and cold water.  Such uses abound.  Creating a big pool of hot
water and big pool of cold water is an example of a process which is
perfectly compatible with the intermittent nature of wind power.  The idea
then would be to compress nitrogen and bubble it up to make hot water, then
drop it across a valve into another chamber to make cold water.

Final word on the argon silos.  If they really mean they are going to get
the gravel to -256 (I assume degrees F) it takes one hellllll of a silo, in
thickness of the walls, since it must hold a lotta lotta pressure on the
warm side, and the thickness of the wall would be proportional to the volume
of the container.


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