|Studies Say Natural Gas Has Its Own Environmental Problems
Natural gas, with its reputation as a linchpin in the effort to wean the nation off dirtier fossil fuels and reduce global warming, may not be as clean over all as its proponents say.
Even as natural gas
production in the United States increases and Washington gives it a
warm embrace as a crucial component of America’s energy future, two
coming studies try to poke holes in the clean-and-green reputation of
natural gas. They suggest that the rush to develop the nation’s vast,
unconventional sources of natural gas is logistically impractical and
likely to do more to heat up the planet than mining and burning coal.
The problem, the studies suggest, is that planet-warming methane, the
chief component of natural gas, is escaping into the atmosphere in far
larger quantities than previously thought, with as much as 7.9 percent
of it puffing out from shale gas wells, intentionally vented or flared,
or seeping from loose pipe fittings along gas distribution lines. This
offsets natural gas’s most important advantage as an energy source: it
burns cleaner than other fossil fuels and releases lower carbon dioxide
“The old dogma of natural gas being better than coal in terms of
greenhouse gas emissions gets stated over and over without
qualification,” said Robert Howarth, a professor of ecology and
environmental biology at Cornell University
and the lead author of one of the studies. Mr. Howarth said his
analysis, which looked specifically at methane leakage rates in
unconventional shale gas development, was among the first of its kind
and that much more research was needed.
“I don’t think this is the end of the story,” said Mr. Howarth, who is
an opponent of growing gas development in western New York. “I think
this is just the beginning of the story, and before governments and the
industry push ahead on gas development, at the very least we ought to do
a better job of making measurements.”
The findings, which will be published this week, are certain to stir
debate. For much of the last decade, the natural gas industry has
carefully cultivated a green reputation, often with the help of
environmental groups that embrace the resource as a clean-burning
“bridge fuel” to a renewable energy future. The industry argues that it
has vastly reduced the amount of fugitive methane with new technologies
and upgraded pipe fittings and other equipment.
Mark D. Whitley, a senior vice president for engineering and technology with Range Resources,
a gas drilling company with operations in several regions of the
country, said the losses suggested by Mr. Howarth’s study were simply
“These are huge numbers,” he said. “That the industry would let what
amounts to trillions of cubic feet of gas get away from us doesn’t make
any sense. That’s not the business that we’re in.”
Natural gas is already the principal source of heat in half of American households. Advocates like the former oil tycoon T. Boone Pickens
have also long sought to promote it as a substitute for coal in
electricity generation or gasoline in a new generation of natural gas
cars. And the development of new ways to tap reserves of natural gas
means production is likely to increase sharply.
Two weeks ago, President Obama
included natural gas in his vision for America. Clark Stevens, a White
House spokesman, said that the administration’s energy priorities were
not about picking one energy source over another, but about diversifying
the nation’s energy mix. “This process will continue to be based on the
best science available to ensure our energy sources, including our
nation’s natural gas reserves, are developed safely and responsibly,”
Mr. Stevens said on Friday.
The ability to pull natural gas economically from previously
inaccessible formations deep underground has made huge quantities of the
resource available in wide areas of the country, including Texas,
Louisiana, Pennsylvania, New York, Wyoming and Colorado.
Such unconventional gas production accounts for nearly a quarter of
total production in the United States, according to the latest figures
from the Energy Information Administration. That is expected to reach 45
percent by 2035.
But the cleanliness of natural gas is largely based on its lower carbon
dioxide emissions when burned. It emits roughly half the amount of
carbon dioxide as coal and about 30 percent that of oil.
Less clear, largely because no one has bothered to look, are the
emissions over its entire production life cycle — that is, from the
moment a well is plumbed to the point at which the gas is used.
Methane leaks have long been a concern because while methane dissipates
in the atmosphere more quickly than carbon dioxide, it is far more
efficient at trapping heat. Recent evidence has suggested that the
amount of leakage has been underestimated. A report in January by the
nonprofit journalism organization ProPublica, for example, noted that the Environmental Protection Agency
had recently doubled its estimates for the amount of methane that is
vented or lost from natural gas distribution lines.
Chris Tucker, a spokesman for Energy in Depth, a coalition of
independent oil and natural gas producers, dismissed Mr. Howarth as an
advocate who is opposed to hydraulic-fracturing or “fracking,” a
practice associated with unconventional gas development involving the
high-pressure injection of water, sand and chemicals deep underground to
break up shale formations and release gas deposits. Mr. Howarth said
his credentials as a scientist spoke for themselves.
Mr. Howarth included methane losses associated with flow-back and
drill-out processes in hydraulic fracturing and other unconventional gas
The study combined these emissions with studies of other methane losses
along the processing and distribution cycle to arrive at an estimated
total methane loss range from 3.6 to 7.9 percent for the shale gas
The researchers include a recent study from the Goddard Institute for Space Studies at NASA
suggesting that an interaction of methane with certain aerosol
particles significantly amplifies methane’s already potent greenhouse
gas effects, particularly over a 20-year time horizon. When all is
factored together, Mr. Howarth and his colleagues conclude that the
greenhouse gas footprint of shale gas can be as much as 20 percent
greater than, and perhaps twice as high as, coal per unit of energy.
David Hughes, a geoscientist and research fellow at the Post Carbon
Institute, an energy and climate research organization in California,
used Mr. Howarth’s research as part of a broader look at natural gas as a substitute for coal in electricity generation and oil in transportation.
Mr. Hughes’s full report is scheduled to be released in May, but in a
draft version shared with The New York Times, Mr. Hughes suggested that
while natural gas would play an important role in the nation’s energy
mix, both cases were practical impossibilities.
“I think it’s going to be very challenging, to put it mildly, to ramp up
shale gas production by fourfold, which is the federal government’s
projection for 2035,” Mr. Hughes said. “I’m not saying it can’t be done,
but if it was done, the amount of drilling you’re looking at to make
that happen is staggering.”
Mr. Hughes, using Mr. Howarth’s calculations, also concludes that
replacing coal with natural gas for base load electricity production
will most likely make greenhouse gas emissions worse. It would be
better, he argues, to improve energy efficiency, rely on natural gas in
niche vehicle markets and balance continued construction of wind and solar power to produce electricity.
David Hawkins, the director of climate programs with the Natural Resources Defense Council,
said that much could be done by regulators to nudge drillers to capture
more of the fugitive methane, but that it is often more economical for
industry to simply let it escape.
Mr. Hawkins also said that too little was known about just how much
methane was being lost and vented, and that studies like Mr. Howarth’s,
while needed, relied on too slim a data set to be considered the final
“This is a huge and growing industry, and we just don’t have the
information we need to make sure that this resource is being developed
as cleanly as it can be,” Mr. Hawkins said.
“We view his shining a flashlight into this dark closet to be a
service,” Mr. Hawkins added, “but the flashlight is still a dim one, and
we still can’t see everything in the closet.”
(« Go Back)