Re: [carfree_cities] Hydrogen Economy & Ozone Layer Debate
- The "hydrogen economy," and you don't have to read too deeply into
matters to discern thsi, is a desperate attempt to keep all the cars we
have now on the road and clogging the Earth's surface and our cities for
as long as possible. That's what it really is.
Mike Neuman wrote:
> From: "Twenty Hydrogen Myths" published at www.rmi.com, by Rocky--
> Mountain Institute. Free online at www.rmi.org. His report was
> updated on 12 July 2003.
> Myth #14. A large scale hydrogen economy would harm the Earth's
> climate, water balance, or atmospheric chemistry. Sub. d. Using
> hydrogen would harm the ozone layer or the climate by leaking too much
> water-forming and chemically reactive molecular hydrogen into the
> upper atmosphere.
"I believe that every right implies a responsibility; every opportunity,
an obligation; every possession, a duty."
John D. Rockefeller, Jr.
- It is doubtful that fuel cells will ever replace internal combustion. The
technical article below quantifies the huge cost of hydrogen fuel. The
hydrogen economy is a mirage.
----- Original Message -----
From: "Richard Risemberg" <rickrise@...>
> The "hydrogen economy," and you don't have to read too deeply into
> matters to discern thsi, is a desperate attempt to keep all the cars we
> have now on the road and clogging the Earth's surface and our cities for
> as long as possible. That's what it really is.
You might find useful parts of this recent letter to the editor of
Chemical and Engineering News (August 25, 2003
Volume 81, Number 34) concerning hydrogen fuel cell
The Woodlands, Texas
Our nation's real need for a viable long-term solution to
renewable energy, especially for private transportation, is not
well served by articles that paint a fanciful picture of the promise
of fuel cells (C&EN, June 9, page 35; June 16, page 16).
Economically viable solutions for the following fuel-cell
challenges seem highly unlikely in the foreseeable future.
The total cost (without subsidy) of proton exchange membrane
(PEM) fuel-cell engines (fuel cells, power conditioning, electric
motors, and so on) with mass low enough to be practical in a
vehicle is in the range of $3,000-$7,000 per kW--40 times that of
the advanced diesel engine. It is worth noting that PEM fuel cells
have been in use and development for 40 years, and costs have
not yet begun to drop significantly--notwithstanding many
assertions to the contrary (such as those in the June 16 article)
that use artificial costs from heavily subsidized projects or cite
costs of massive, stationary fuel cells that are unsuitable for
Safety-approved affordable compressed-gas cylinders achieve
1.5% H2 storage by mass at 34 MPa (5,000 psi). A $25,000
carbon-fiber-wrapped fuel tank achieving 6% H2 storage seems
impractical for the small private car, and liquid hydrogen (LH2)
doesn't keep long. The huge mass penalty associated with
economical H2 storage seems likely to keep the mileage of
fuel-cell-powered automobiles (of acceptable range,
acceleration, cost, and cargo capacity) below 25 miles per kg of
H2 for many decades.
Current U.S. H2 production is enormous--about 2 x 1010 kg per
year. Yet the current pretax cost of LH2, delivered in 15,000-gal
(4,300-kg) tankers to high-volume customers, is $4.30 per kg,
and other methods of H2 distribution are even more expensive.
On the other hand, the current U.S. pretax cost of gasoline for the
individual consumer at the local station is about 30 cents per kg.
The only economically viable sources of H2 in the U.S. are
natural gas and coal. The nearly adiabatic
partial-oxidation/reformation/shift reactions use 3 kg of natural
gas (90% CH4) to produce 1 kg of H2 plus 9.5 kg of CO2. Then
more than 3 kg of coal must be burned (releasing another 10 kg
of CO2) to generate the 10 kWh (36 MJ) needed to purify and
liquefy 1 kg of H2. The energy efficiency in producing LH2 is
under 50%. (This number has not budged in 15 years and will
not in the next 50. We're near Carnot limits.) The energy content
of 1 kg of H2 is equivalent to 2.8 kg (1.1 gal) of gasoline, which
contains only 2.3 kg of carbon.
At 80 miles per gallon, the advanced diesel hybrid achieves 7
miles per kg of total CO2. The fuel-cell automobile at 25 miles
per kg of hydrogen achieves 1.1-1.3 miles per kg of total CO2.
Hence, when miles per kg of CO2 release ("fossil mileage") is
more fairly calculated, the total CO2 generated per mile by a
hydrogen vehicle is likely to be five times that of a comparable
diesel-powered hybrid vehicle for at least four decades. (If we
have not been able to raise fuel taxes a nickel in the past two
decades, how can we expect to impose a $1.00 per kg surtax on
H2 production to support CO2 sequestration?)
It is most interesting to note that, seven years ago, the
Department of Energy expected fleets of fuel-cell-powered
vehicles to be in use by now. Today, they are projecting that will
occur seven years from now. Undoubtedly, if DOE invests $2
billion (as expected) over the next seven years, many more
demonstration vehicles (at $300,000 each) will be on the road,
but that really does not accomplish much. I expect to still see that
"seven-year" projection for commercial fleets 20 years from now.
It's time we start putting some serious money into real options
for our future transportation needs.
F. David Doty