Used in rockets and in battery-like fuel cells, hydrogen is being
widely researched as a non-polluting fuel, but its use is so far
hampered by high costs. A few hydrogen vehicles are already on the
roads, such as the Honda FXC Clarity and Mercedes-Benz F-Cell, and
more are planned.
Researchers in France said aluminum oxide speeded up a process by
which hydrogen is produced naturally when water meets olivine, a
common type of rock, under the high temperatures and pressures found
at great depths.
"We have overcome a preliminary step for a carbon-free energy
production," lead researcher Muriel Andreani of the University
Claude Bernard Lyon 1 in France told Reuters.
The addition of aluminum oxide accelerated the natural process by
between 7 and 50 times, using temperatures of between 200 and 300
degrees Celsius (400-570 Fahrenheit) at a pressure equivalent to
twice the depth of the deepest ocean.
In the process, olivine turns into the mineral serpentine and water
splits into its components, hydrogen and oxygen.
Currently, the most widely used technology for producing hydrogen —
separating it from natural gas — requires far higher temperatures of
700 degrees Celsius (1,300 Fahrenheit) and releases heat-trapping
carbon dioxide as a by-product.
Using lower temperatures would save energy and money.
WATER VAPOR
Fuel cells, which meld hydrogen with oxygen in the air to yield
electricity, emit only water. That makes them attractive as a way to
cut greenhouse gas emissions and air pollution.
Far more research is needed to see if the French findings could be
increased to a commercial scale, said Jesse Ausubel of the
Rockefeller University in New York.
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"Scaling this up to meet global energy needs in a carbon-free way
would probably require 50 years," he said in a statement. "But a
growing market for hydrogen in fuel cells could help pull the
process into the market."
The findings will be presented to the American Geophysical Union,
meeting in San Francisco from December 9-13, after an initial report
in the journal American Mineralogist in October.
The work is part of the Deep Carbon Observatory (DCO), a 10-year
project due for completion in 2019 involving 1,000 researchers in 40
nations.
Among puzzling DCO findings, experts said, microbes living in tiny
fissures in deep rocks where hydrogen forms naturally, often
continents apart, seem to be related to one another in what may be a
"deep subterranean microbe network".
Matt Schrenk of Michigan State University said life extended to at
least 4 or 5 km (2.5-3 miles) deep under land, and it was unclear
how similar microbes had spread to places as far apart as South
Africa, North America and Japan.
"It is easy to understand how birds or fish might be similar oceans
apart, but it challenges the imagination to think of nearly
identical microbes 16,000 km apart from each other in the cracks of
hard rock at extreme depths," he said.
The DCO project is trying to combine chemistry, biology, geology and
even astrophysics. "It is a path to discovery between new areas of
science," Robert Hazen, head of the DCO at the Carnegie Institution
of Washington, told Reuters.
(Editing by Mark Heinrich)
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