- CASPER, Wyo. (AP) -- The
U.S. government is trying to bury something at its Teapot Dome oil field
again. Not secret oil leases, as it did during an infamous scandal of the
1920s, but carbon dioxide - lots of it.
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- In hopes of developing a process that could slow global
warming, the Energy Department wants to inject the greenhouse-gas underground
into depleted oil reservoirs after converting it into a liquid form.
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- The Teapot Dome project, now in the planning stages,
could be one of the world's largest test sites for the method. It would
store CO2 from a natural gas processing plant about 500 kilometres away
beneath the 40-square-kilometre oil field in central Wyoming.
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- So-called carbon dioxide sequestration has been tested
at smaller sites nationwide but never on such a large scale, said Vicki
Stamp, a project manager for the Rocky Mountain Oilfield Testing Center,
which manages Teapot Dome.
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- Used in enhanced oil recovery for decades, pumping carbon
dioxide into underground reservoirs is being touted by the Bush administration
as one of the most promising ways to counter the greenhouse effect.
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- "(Carbon dioxide) is the primary global greenhouse
gas and it's growing rapidly," said Dag Nummedal, director of the
University of Wyoming Institute for Energy Research. "During the last
four or five years, the international consensus is that the most rational,
economic and environmentally benign way of getting CO2 out of the atmosphere
is to store it underground.
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- "Right now, the best place to do this is in depleted
oil and gas fields."
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- Teapot Dome - named for a nearby rock formation - is
currently in its preliminary engineering and testing stages. Storage could
begin by 2006 and last seven to 10 years, although Mr. Nummedal said managers
"don't really know the upper limit yet."
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- When a reservoir is full, the pipeline is taken out and
the hole sealed up. "The objective is to keep it sealed underground
forever, hundreds or thousands of years," he said.
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- The site is projected to store at least 1.5 million tonnes
of carbon dioxide a year when fully operational. It could eventually lead
to large-scale testing in other Rocky Mountain states, the Ohio River Valley,
Texas Gulf Coast, California and other areas, Mr. Nummedal said.
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- "The long-term plan is to encourage the growth of
a new private sector sequestration industry."
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- Talk of a national CO2 testing centre started early last
year, but it was not until managers found a source of carbon dioxide later
that summer that the idea became a reality.
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- Anadarko Petroleum Corp., which owns an adjacent oil
field, is extending its existing CO2 pipeline from a natural-gas processing
plant in western Wyoming and has agreed to direct some of its 3.5 million
cubic metres of CO2 to the test site, Mr. Nummedal said.
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- The gas will then be put under pressure and injected
as a liquid into the reservoirs through a pipeline. It could stay underground
for a very long time, since the reservoirs that would store the CO2 held
oil and methane gas for millions of years, said Susan Hovorka, a University
of Texas researcher.
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- "That's not true of other mechanisms," she
said. "If you grow more (trees, which consume carbon dioxide) how
do you assure it doesn't all go up in a forest fire or that another generation
decides to go ahead and farm that area?"
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- Burial can also rid the Earth of a large volume of carbon
dioxide in a relatively short amount of time, Ms. Hovorka said.
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- "We've got almost all the carbon dioxide emitted
in the atmosphere coming from fossil fuels," she said. "There's
space equivalent in acreage to put all that carbon dioxide back underground."
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- If the project pans out, officials hope to capture CO2
from U.S. power plants, oil and gas refineries and other manufacturing
facilities "because that is the CO2 today that is leaking into the
atmosphere without any controls on it," Mr. Nummedal said.
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- One possibility is capturing the gas with scrubbers similar
to those attached to smokestacks that remove nitrous oxide and other gases,
he said.
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- The storage process - particularly compressing the CO2
- is expensive. Some estimates put it as high as $100 a tonne, though Mr.
Nummedal and others said they do not have cost estimates for Teapot Dome.
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- Even if it is a success, the Teapot Dome project could
have little impact by itself.
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- "Globally we are releasing seven billion tonnes
of carbon per year," Mr. Nummedal said. "The amount we will be
putting away here will be in the hundreds of thousands of tons."
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- But he added: "If we look at all the suitable, depleted
oil and gas reservoirs in the world, and we were able to fill all of them
up, we would be able to store the total global emissions over the next
100 years."
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- Some environmentalists worry about gas bubbling through
cracks in the Earth or leaking into aquifers that supply drinking water.
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- "We very clearly need some field demonstrations
of a storage system to make sure (we) don't have any surprises," said
David Hawkins, director of the Natural Resources Defense Council's Climate
Center in Washington, D.C.
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- Mr. Nummedal and others stress that they are testing
Teapot Dome reservoirs for those concerns.
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- "The early steps of this co-operative venture show
the classic markings of a win-win proposition for American consumers,"
Energy Secretary Spencer Abraham said.
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