[ExI] THE END for fossil power

[Eugen Leitl]

On Sun, Apr 03, 2011 at 12:15:44PM -0600, Kelly Anderson wrote:

> Some of the main challenges with hydrogen vs. synfuel are:
> 1) Storage. Hydrogen being such a small molecule, it escapes any
> attempt to contain it with relative ease.

The petrochemical industry maintains a considerable
high-pressure hydrogen pipeline network across much
of Europe. Hydrogen at normal pressure is no big deal,
and can be easily stored in gas holders. Hydrogen in
pressurized gas cyliders is also old, familiar stuff.
There is some volatility with ultra-high pressure
composite storage for vehicles. I frankly think it's
a stupid idea. There's more hydrogen in methanol than
in liquid hydrogen, by volume.

> 2) Energy density. Hydrogen stores less energy per pound of fuel.

Not a problem for stationary applications. In case of EV, consider
that ICEs have a street efficiency of about 20%.

> 3) Expense. Hydrogen fuel cells (the most direct way to turn hydrogen
> into electricity) are currently rather expensive.

Hydrogen burns just fine, and in micro co-gen efficiency is >90%.

> 4) Infrastructure. Converting from current fuel systems to hydrogen is
> massively expensive. Current pipelines don't handle hydrogen well (see

Depends, catalytic burners do fine, as to Stirlings.

> point 1).

Only high-pressure pipelines for natural gas. Yes, you need special
pipe materials, larger crossections and different pumps.

> 5) Public acceptance. People still equate hydrogen with the
> Hindenburg. In some ways, hydrogen is kind of like nuclear power in
> the sense that people don't understand the true risks. Technological
> solutions, and public experience will overcome this, I hope.

Small scale hydrogen should take care of that.

> 6) Some places with lots of energy don't have lots of water. Arizona
> (solar) Wyoming (wind). This probably isn't a major issue.

Water demand is negligible, there's 55.5 mol/l in water.
 
> The energy density problem is particularly difficult in mobile
> applications (cars).

Hydrogen doesn't work in cars very well, and probably never will.
Liquid hydrogen could be quite interesting for aerospace, however,
 
> Hydrogen sounds like a great idea. It is a great idea. We just need
> more research to make it practical and we need to understand its

The research part is already done. Apart from minor things like
really cheap and durable hydrogen fuel cells.

> limitations, particularly with regard to energy density. Some schemes
> for packing the hydrogen into latices have been proposed which would
> solve this problem, if they can actually build them.

The energy density is a non-issue for immobile applications.
 
> Of course, synfuels still have the familiar problems including
> pollution and CO2 production.

Synfuels from CO2 scrubbed from air or fuel gas are carbon neutral
by definition. E.g. DMFC ran from synmethanol obviously has a very
good carbon and pollution story, nevermind efficiency.

-- 
Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org
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