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  • From: "Lee Flier" <lflier@mindspring.com>
  • To: permaculture <permaculture@lists.ibiblio.org>
  • Subject: [permaculture] Re: Hydrogen
  • Date: Tue, 17 Jun 2003 12:48:24 -0500

Mike wrote:

> This very valid point has been missed by most of the reporters and
> popularizers. It is also ignored by the energy industry, who want hydrogen
> just because
> it will make them sound like they're more eco-friendly.

Yes, and it will also allow them to continue with business as usual, because
it will take a heck of a lot of conventional energy to support a hydrogen
economy.

> But it's pretty
> obvious to the scientific world.

Yes, and it astounds me to hear things like President Bush's speech in which
he touted hydrogen as a way to free ourselves of dependence on Middle Eastern
oil. Not that I really should be surprised, I've been seeing this coming for
several years now.

> Please offer any information you've seen about the efficiency of converting
> water to free H and O. I think it's a little better than that.

The process is about 30% efficient, currently. The best electrolyzers are
about 50% efficient, but then the resulting hydrogen must be purified before
it can be stored, which of course uses more energy.

So this means it takes about 3 times the energy to extract the hydrogen from
water, as you can get from the resulting hydrogen. And that doesn't count
getting it into a cell and shipping it somewhere. Where is all this energy
going to come from?

> Also you could put it more accurately by saying that the major fuel corps
> are
> hyping conversion from natural gas, as they sell more gas that way.

I wish that were true, but it simply is not. The process of extracting
hydrogen from natural gas is about 60% efficient or twice the efficiency of
getting it from water. There simply is a lot more hydrogen, and in a much
purer form, in natural gas. But then of course you might as well just burn
the natural gas, which is again more efficient and which we already do.

Think about it - if it really were feasible to produce a usable amount of
hydrogen from water, the energy companies would be all over it. Let's not
forget that existing energy companies have been some of the biggest investors
in alternative energy. BP/ARCO was one of the first to sell solar panels
commercially, Edison Electric has built several large wind farms. Don't
think they wouldn't love to find a cheap local source of energy - not because
it's eco-friendly but because the process of finding, extracting and shipping
fossil fuels is very expensive and often difficult to control, what with all
the two-bit dictators and various warring tribes who run the major oil
producing nations. :)


>That is not to say that disinterested research
> isn't being done by independent scientists. There's quite a lot of it, in
> fact,
> and the promise I was suggesting was that offered by renewable energy
> sources.
> Obviously any conversion of renewable energy like wind power into vehicle
> fuel
> is going to reduce demand on fossil fuels.

Yes, but that wind power would be put to much better use as simple
electricity. Renewable energy produces precious little power as it is, and
when you start converting it to hydrogen the numbers get stupid. See my
quote at the end of this post for more details.

> My concern is that when you dismiss the whole notion as "dangerous myth"
> you
> throw out the potential for useful applications being discovered.

Actually, what I'm trying to accomplish by pointing out the dangerous myths,
is exactly the opposite. If people are lulled to sleep by believing hydrogen
will "save us" along with our current level of energy usage, they will fail
to ever look closely enough to see the practicality or impracticality of any
specific application. Most of the applications being touted now are
completely unfeasible and as you say are being touted because of their
usefulness to the status quo. We simply can't afford to believe the kind of
crap that gets thrown around.

> Right now,
> research is going forward in a dozen different directions to find new
> methods
> of producing energy sources from low-value agricultural products like
> feedlot
> wastes, offal and chaff. If these methods can create more biogas than can
> readily be used in the form of gas, why not convert some of the product
> into an
> energy store like hydrogen? That way it has more uses.

Sure. There's also very promising research involving certain breeds of algae
that offgas nearly pure hydrogen. There may be some locations and some
applications where it's practical to do this on a small scale... but I really
don't think people grasp the actual logistics of a hydrogen economy (again,
see below).

> Think of hydrogen as being the same thing as a battery-- it makes energy
> more
> portable.

Exactly. That is the analogy I always use as well. Hydrogen is NOT a "fuel"
- it does not put net BTU's on the books, it only stores energy from another
source, and not very efficiently at that. It's that "other source" that we
still need to be concerned with.

I'll close with a quote from an article that I have reposted several times
over the years, which was published in Home Power Magazine
(http://www.homepower.com). I strongly urge anybody interested in
alternative energy to subscribe to Home Power or read online for free. I've
been reading them for years and these guys are the most gung-ho, the geekiest
of the geeks, and they really stay on top of and experiment with the latest
technologies and processes. There've been several articles over the years
for example, from people who set up electrolyzers at home and power them with
solar energy. All fairly consistently report that it takes about 5.9 KwH of
electricity to produce a cubic meter of hydrogen. With that cubic meter,
these folks can run their gas space heater for a whopping two hours. They
needed an array of 32 PV panels to keep even this very rudimentary system
going. I dunno about you, but 1) I can't afford 32 PV panels, and 2) I could
think of a lot better uses in my home for 5.9KwH of solar electricity than
running a gas heater for two hours. And if we were to use the hydrogen to
store electricity against cloudy days, converting the hydrogen back to
electricity gets even stupider. It makes FAR more sense to store the energy
from my PV panels in plain old lead acid batteries, most of whose parts are
recyclable and which these days only need to be replaced every 7-15 years.

Anyhow, here are some excerpts from the article in Home Power that I
mentioned, written by Conrad Heins in 1991 (efficiency has improved slightly
since then, but does not change the overall picture):

<begin quote>----------------------------------------------------

Although it will most likely play a role as a fuel in a renewable energy
society, I believe that at the present time it is a mistake to push the use
of hydrogen as a substitute for non-renewable carbon based fuels. Let me
explain why.

..First and most importantly, the proposal to substitute hydrogen for other
fuels is addressing the problem from the wrong end. We should be concerned
far more with reducing the need for fuel, through conservation and improved
energy efficiency, than with replacing a "dirty" fuel with a "clean" one. .
We need to focus not on the supply-side but on the demand side of the energy
equation.

A second, related point is that by addressing the problem in terms of supply
we tend to ignore how the energy is being used, We fail to ask the critical
question, "Is this particular kind of energy the best answer for this
particular application?" Only when this question is posed are we able to to
make judicious choices, especially if we want to take into account the
second law of thermodynamics efficiency considerations, which deal with
energy quality as well as energy quantity, or environmental impacts.

..The formation of hydrogen and oxygen from water using electricity is the
one that is most often touted. If the electricity is provided by PV panels,
we are talking about using a renewable energy resource, sunlight, to provide
hydrogen in a non-polluting way. Such a proposal, when first heard, sounds
attractive. However, a little further examination indicates that is not a
good answer.

The biggest problem is the prodigious amount of electrical energy that would
be required to replace even a portion of the hydrocarbon fuels we now use.
Wilson Clark, in his classic book, Energy For Survival, makes his point very
clear. "The amounts of hydrogen that would be required in a hydrogen economy
are enormous. For instance, according to Dr. Gregory, to produce enough
hydrogen to fully substitute for the natural gas produced in the United
States at the present time [1974] --i.e., 70 trillion cubic feet of
hydrogen-- would require more than 1 million megawatts of electric power to
produce. Total electric generating capacity in the United States is only
360,000 megawatts. To meet the projected hydrogen requirements for natural
gas alone would call for a fourfold increase in generating capacity, which
would mean building 1,000 additional 1,000-megawatt power stations! This
does not provide for increased electric power demand for other purposes, nor
does it take into account the generation of hydrogen for transport fuel or
as an additive in chemical and industrial processes."

By way of comparison, world production of photovoltaic generating capacity
was about 50 megawatts (peak sun) last year. Even if this capacity were to
be increased a 100-fold and all of it used to produce hydrogen, we would
still be making a fraction of 1% of what would be needed to replace the
natural gas consumed in the U.S.

----------------------------------------------------------------------------
<end of quote>


--Lee

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