Road to Hydrogen Cars may not be so clean

From: Tom Simonds (tsimonds_at_theworld.com)
Date: 12/20/04 

Date: Mon, 20 Dec 2004 08:11:09 -0500

Road to hydrogen cars may not be so clean
Environmental peril in making, containing fuel

Keay Davidson, Chronicle Science Writer

Monday, December 20, 2004

Auto-industry ads depict hydrogen cars as the vehicular route to clean,
blue skies.

President Bush and Gov. Arnold Schwarzenegger are among their biggest
champions.

The politicians' enthusiasm for the technology -- a leading proposal to
solve global warming -- is shared by many scientists.

But reality could prove more complex, some critics say. Among the
problems detailed at the American Geophysical Union conference in San
Francisco last week:

-- Hydrogen is a very "leaky" gas that could escape from cars and
hydrogen plants into the atmosphere. This could set off chemical
transformations that generate greenhouse gases that contribute to
atmospheric warming.

-- The extraction of hydrogen for cars from methane, which is currently
the richest available source of hydrogen, will generate carbon dioxide,
a major greenhouse gas.

-- Hydrogen can also be extracted from ordinary water via a process
called electrolysis. However, using current technology, mass
electrolysis of water would require intense sources of energy. If those
energy sources burn fossil fuels, they, too, would generate greenhouse
gases.

These problems are not necessarily showstoppers, and they may be
overcome by future technical innovations. In any event, many scientists
believe the environmental problems posed by hydrogen cars may prove to
be less severe than the problems generated by today's
fossil-fuel-dependent cars.

But given such issues, some experts are cautioning that much more
research is needed before the nation prematurely commits itself to
developing the "hydrogen economy."

"I'm supportive of research and development, but we are at least two
decades away from (deploying) the vehicles on a mass level," said
MIT-educated physicist Joseph J. Romm, a former U.S. Department of
Energy official, in an interview. Romm's book, "The Hype About Hydrogen:
Fact and Fiction in the Race to Save the Climate," was published earlier
this year by Island Press.

"Americans are very much believers in technology and optimism, and yet
when you look at the compelling details" about hydrogen cars, Romm said,
"it doesn't make bloody much sense."

Economically, hydrogen devices remain highly unattractive: "Fuel cells
are very expensive," Romm said. "The demonstration vehicles all cost
hundreds of thousands of dollars."

Atmospheric scientists, meanwhile, are trying to figure out how Earth's
atmosphere would be affected by leaked hydrogen from cars, hydrogen gas
stations, delivery trucks and hydrogen production plants. Unfortunately,
the politicians aren't necessarily getting the best scientific advice on
the atmospheric issue, said Professor Michael J. Prather of UC Irvine at
the geophysics conference on the atmospheric impact of hydrogen cars.

A 2004 National Academy of Sciences report on "The Hydrogen Economy" was
prepared by "economists and engineers, remarkably lacking any
atmospheric scientist or biogeochemists who understand the natural
(atmospheric) cycle of H2," said Prather, a professor of Earth system
science and former editor-in-chief of Geophysical Research Letters. "It
is surprising that all of these groups examining a hydrogen economy are
secure in the belief that H2 is a pure fuel, safe and harmless to the
environment," although studies suggest otherwise.

One problem is that hydrogen leaked into the atmosphere binds with
oxygen molecules, forming water vapor and clouds. A change in cloud
abundance in some regions might alter the local temperature and
climate -- for example, the climate might warm if the clouds trap heat
like blankets, or the climate might cool if they reflect sunlight back
into space.

"The widespread use of hydrogen fuel cells ... would cause stratospheric
cooling, enhancement of the heterogeneous chemistry that destroys ozone,
an increase in noctilucent clouds, and changes in tropospheric
(lower-atmosphere) chemistry and atmosphere-biosphere interactions,"
scientists from Caltech and Jet Propulsion Laboratory in Pasadena
proposed in the journal Science in 2003. Noctilucent clouds are eerie
high-altitude clouds whose abundance, some scientists suspect, is
influenced by climate change.

Despite the uncertainties about the climatic impact of a hydrogen
economy, Prather added sardonically, "The promise of a clean,
hydrogen-fueled transportation sector has been waved in front of the
nation by the current administration, the governor of California and the
technologists."

And even though optimists say hydrogen will be generated via
electrolysis without producing greenhouse gases, the reality is that the
oil companies are gearing up to generate it from methane -- and the most
famous greenhouse gas, carbon dioxide, forms as an unintended byproduct
of the methane-treatment process.

Prather cited Shell Oil's online "Answer Man" page, where a customer
asked where the hydrogen for hydrogen cars will come from. The Web
site's answer: methane. Kenneth S. Deffeyes, a Princeton University
geoscientist and former Shell Oil Co. engineer and author "Beyond Oil,"
to be published in March by Farrar, Strauss and Giroux, also has
concerns about hydrogen production.

Although a Shell-pioneered hydrogen filling station in Iceland looks
attractive because of its environmental cleanliness, Deffeyes said,
Americans need to remember that the much-publicized station is powered
by hydroelectric and geothermal electricity, neither of which produces
greenhouse gases, "because all the electric power in Iceland is
hydroelectric and geothermal."

The National Academy of Sciences report, issued in February and chaired
by a retired executive vice president of Exxon/Mobil's research arm, did
sound a cautionary note that in a hydrogen economy, "reductions in
annual carbon emissions could be achieved ... but ... they would vary
greatly depending, for example, on whether hydrogen fuel was generated
from fossil fuel resources ... or ... whether electrolysis was used and
powered by renewable energy sources, among other factors and choices,"
the report said.

Skeptics also point out that because of the hydrogen molecule's small
size and volatility, it is an extremely leak-prone gas that must be
closely monitored.

Scientists must learn the "potential leak points" -- the ways in which
hydrogen can leak from cars, plants and other sources -- before there is
a major shift to a hydrogen economy, Catherine G. Padro of Los Alamos
National Laboratory said at the same geophysics session. Scientists, she
said, "do not want a repeat of CFCs," or chlorofluorocarbons, the
industrial pollutants that started the destruction of part of Earth's
atmospheric ozone, which shields us from cancer-causing solar radiation.

But other scientists say that even if hydrogen leakage generates a small
amount of global warming, that would be a relatively minor problem
compared with the advantages of switching from a fossil fuel-based
transportation system to a system fueled by hydrogen.

If such a mass switchover to methane-derived hydrogen occurred, the
nation's total emission of greenhouse gases could decline between 10 and
50 percent, according to studies by MIT and Argonne National Laboratory
near Chicago, Anthony Eggert, associate director for research in the
"Hydrogen Pathways" program at UC Davis, said in an interview.

Eggert calls himself a "realistic optimist" about hydrogen cars. On the
one hand, he said, "The vehicle itself is not something that you could
afford to buy today because the components within the fuel cell system
are still very expensive." Also, it wouldn't travel as far on a single
"tank" as today's cars: "You'd have to fill up maybe once every 150 to
180 miles."

On the other hand, Eggert said, "The automakers are making incredible
progress in reducing costs and increasing reliability and durability."

One problem, skeptics say, is that a switchover to a hydrogen economy
may not occur smoothly enough to avoid making environmental troubles in
the interim.

"What we cannot do," Deffeyes writes, "is get the electricity (for
hydrogen generation) from an existing dirty coal-fired electrical power
plant and claim that the environmental bookkeeping begins only after we
buy the electricity."

"If (electrolytic) hydrogen is to be an environmental success, expanding
the electrical-generating system necessary to produce it has to be an
environmental success," too, he said -- which means looking to
hydroelectric and geothermal power, as in Iceland, or solar, wind and
nuclear power.

The nation's invisible breezes may yet provide a solution.

The United States has enough wind energy -- which produces zero
greenhouse gases -- to electrolytically generate enough hydrogen to
support the nation's entire vehicular fleet, said atmospheric scientist
Mark Z. Jacobson of Stanford at the geophysics session.

Jacobson showed conference attendees a graphic that pinpointed windy
places across the United States -- not just in Northern California but
also in the Midwest and along the Atlantic coastline -- that could
support electrolysis for hydrogen-gas fuel plants.

"There's lots of wind out there," he said.

E-mail Keay Davidson at kdavidson@sfchronicle.com