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HYDROGEN CARS: Another Dumb Bush Pipe-Dream You Won't See In This Lifetime!

Von: Suppurating Tool (kinkysr@yahoo.com) [Profil]
Datum: 18.11.2009 03:27
Message-ID: <5b88d337-bc44-438b-a3b2-53050b8a2d5e@e31g2000vbm.googlegroups.com>
Newsgroup: sci.physics alt.impeach.bushsoc.culture.usa alt.autossci.energy.hydrogen
H-car proponents state (in a mantra repeated so often that is accepted
as gizmo gospel by many intelligent adults) that a fuel-cell vehicle's
"only emission is water vapor." That is true, but only in a trivial
and thoroughly misleading sense."


-----------------
"Don't bet on a hydrogen car anytime soon"

By Curt Suplee
Tuesday, November 17, 2009


Just in time for Thanksgiving, a familiar techno-turkey is back on the
national policy table: the hydrogen-powered car. The Obama
administration had flatlined funding for President George W. Bush's
pet initiative, briefly but heavily touted a few years back as the
driving force toward a future "hydrogen economy" in which gas would
displace gasoline.

Two wars and a financial sinkhole later, most Americans had managed to
forget the whole thing. But then last month the Senate improbably
restored $187 million for H-car research programs to an appropriations
bill.

Okay, that's barely enough to cover one year's bonuses on the lower
floors at AIG. But why is it there at all? The answer lies in the
persistent, hypnotic allure of hydrogen eco-mythology, with its
promise of breaking our addiction to fossil fuels and foreign oil
while banishing greenhouse pollution from our skies -- a vision most
pointedly embodied in the hydrogen car. Or, more accurately, the
notion of the hydrogen car.

The prototypical H-car is powered by electrical current from a fuel
cell, a device that combines hydrogen and oxygen to produce
electricity. The principle involved is a schoolroom classic: If you
stick two electrodes into a beaker of water, the electrical energy
breaks H2O apart into its ingredients, H and O, in a process called
electrolysis. A fuel cell does the same thing in reverse, putting
separate H's and O's back together into water molecules and thereby
producing electrical energy, which can be used to run a motor.

It is this reaction that allows H-car proponents to state (in a mantra
repeated so often that is accepted as gizmo gospel by many intelligent
adults) that a fuel-cell vehicle's "only emission is water vapor."
That is true, but only in a trivial and thoroughly misleading sense.

To understand why, you need to recall two fundamental facts. The first
is that, unlike oxygen, hydrogen doesn't grow on trees. Although it's
the most common element in the cosmos, it isn't found in a pure state
on our planet. There are no subterranean "hydrogen pockets" equivalent
to coal beds or natural gas deposits. Hydrogen has to be extracted
from compounds into which it is firmly bound and which it really
doesn't want to leave.

The standard method, which is used in 95 percent of all U.S. hydrogen
production today, is to strip it out of natural gas, a procedure that
generates copious emissions of carbon monoxide and carbon dioxide,
though probably not as much as burning the gas outright. This method,
of course, consumes fossil fuel -- the very scenario that the hydrogen
car was intended to avoid in the first place.

Alternatively, you can get hydrogen from coal or alcohol (with
emissions ditto), or you can coax it out of other chemical reactions,
or you can breed bacteria to exhale it. And, of course, you can get it
out of water by electrolysis.

Each method has an energy cost, which brings us to the second
fundamental fact: The energy we consume usually has changed forms
repeatedly by the time we get it. Turn on a toaster and you're using
electrical energy to create heat energy. But the electrical energy
originally came from chemical energy in coal, which was converted to
thermal energy, which was converted to mechanical energy that ran a
generator to produce electrical energy.

Such ingenious chains of conversion make modern civilization possible
and have enabled the United States to lead the free world in
production of wall-mounted singing rubber fish. But nature extracts a
substantial tariff on each transaction; that is, some energy is always
lost. No conversion can be 100 percent efficient, and many are far,
far less.

A conventional automobile engine is able to convert into useful work
maybe 25 percent of the chemical energy in gasoline. The energy in the
light from an incandescent bulb represents about 2 percent of the
chemical energy in the coal that was burned to make the electricity
that powers the bulb.

The latest hydrogen fuel cells are about 50 to 70 percent efficient,
so they might start to look pretty good, even if they're ferociously
expensive and require scarce platinum as a catalyst.

But why would you want to store energy in the form of hydrogen and
then use that hydrogen to produce electricity for a motor, when
electrical energy is already waiting to be sucked out of sockets all
over America and stored in auto batteries -- all without a middleman?

Moreover, even if pollution-free hydrogen were available -- produced,
say, by electrolysis using zero-emissions energy from wind turbines --
you'd still need a way to move enormous amounts of it around the
country the way gasoline is delivered now. That raises a whole new set
of problems. Hydrogen has relatively low energy content per unit
volume, about one-third that of natural gas or gasoline. So it would
have to be tightly compressed, probably to thousands of pounds per
square inch, all without leaks of the highly flammable stuff that
could turn the corner "gas" station or family sedan into a mini-
Hindenburg.

None of that is impossible. It's just stupendously difficult and
probably pointless. That's why, for the foreseeable future, the
hydrogen car will remain a tailpipe dream.

http://www.washingtonpost.com/wp-dyn/content/article/2009/11/16/AR2009111602668.html

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