[ExI] THE END for fossil power

[Kelly Anderson]

On Sun, Apr 3, 2011 at 2:10 PM, Eugen Leitl <eugen at leitl.org> wrote:
> 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.

At what cost? This goes to the infrastructure issue. Europe is of
course more dense than the US, and such infrastructure typically costs
us more because the pipes are longer. I wonder if there is any
significant leakage from the European system. Of course, electricity
is lost in long distance transmission, so this could be seen as an
equivalent sort of loss.

> 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.

The public face of hydrogen is that the exhaust produced is water.
Turning clean hydrogen into methanol, ethanol or some other
petrochemical that produces toxic exhaust is going to make it less
desirable from that point of view. Unless the full synthetic burns
much cleaner... but I don't know if it would. It is no surprise to me
that methanol has more hydrogen by volume.

>> 2) Energy density. Hydrogen stores less energy per pound of fuel.
>
> Not a problem for stationary applications.

True enough.

> In case of EV, consider
> that ICEs have a street efficiency of about 20%.

Sorry, no comprendo EV? ICEs?

>> 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%.

So you're saying you could just burn hydrogen in a little generator?
Would that be as clean as a fuel cell? Would there be pollution as a
side effect?

>> 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.

But the current oil/gasoline infrastructure can't handle hydrogen... I
understand that replacing all of the gasoline infrastructure with
equivalent hydrogen infrastructure would cost billions if not
trillions.

>> point 1).
>
> Only high-pressure pipelines for natural gas. Yes, you need special
> pipe materials, larger crossections and different pumps.

i.e. it will be quite expensive.

>> 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.

We can hope.

>> 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.

Just to double check. Suppose that a wind turbine creates 1 MWatt. To
store 1 MW in hydrogen using electrolysis for a day, how much water is
required?

>> 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,

That's too bad since people are so focused on it.

>> 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.

And mass production... there is a lot of research and development
needed to produce this stuff on a mass scale. In addition, I've heard
of interesting research on ways to pack more hydrogen into matrices
such that you might be able to carry months worth of fuel in a very
small package. Whether such research is practical or not remains to be
seen, but it is very interesting, and if it is successful, it will
make hydrogen practical for automobiles.

>> 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.

Yes, but it is a big issue for mobile 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.

I don't personally care as much about CO2 as pollution. Are synfuels
pollution free? I'm guessing not... but would be pleasantly surprised
if they were.

-Kelly