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| Part of compressor station in Bradford County, PA |
A new
study finds that methane leaks from the production and transportation of gas
could be 50 percent higher than EPA estimates. It also warns that switching
vehicles from traditional gasoline and diesel to natural gas will do nothing to
slow climate change.
“Methane Leaks from North American Natural Gas Systems” is a policy paper - a collaborative
effort by sixteen academics who reviewed and synthesized data from 200 papers
published in the past two decades.
The lead
author is Adam Brandt, an assistant professor of energy resources engineering
at Stanford University. In comments to the press, he explained that official
agencies such as the EPA are underestimating leakage of natural gas into the
atmosphere. Brandt reminded people that leaked methane is a greenhouse gas, just
like carbon dioxide, but 30 times more potent. He also noted that although converting
fleets from diesel to natural gas sounds like a good idea – burning gas puts
less carbon into the atmosphere than burning diesel – any potential climate
benefits would be negated by the leaked emissions from gas drilling and
production.
Those gas
leaks come from emissions at well pads, storage tanks, old and abandoned wells,
abandoned infrastructure, and holes in pipelines. Brandt estimates there are at
least 400,000 gas wells – a low estimate given that the US Energy Information
Administration tallied up more than 510,000 back in 2010. As for pipelines,
“there are millions of miles,” he said in a video press release last week.
Brandt characterizes gas as “abundant, cheap and domestic” and seems to approve
of using it to replace coal in power production. But the gas industry needs to
plug the leaks. It’s in the industry’s best interest, he says. Those emissions
represent lost money and if the country hopes to use gas as a fuel “then we
need to get leakage under control.”
Tony
Ingraffea agrees that there is more methane escaping into the atmosphere than
is accounted for by EPA studies. But he criticizes Brandt et al for not going
far enough in their review. Ingraffea, a professor at Cornell’s School of Civil
and Environmental Engineering, co-authored an earlier study warning that
extracting natural gas could do more to aggravate global warming than mining
coal.
The problem
with Brandt’s study, says Ingraffea, is that it ignores some important data. In
particular, the authors eliminated data that seemed “too high” – even though
they were actual measurements. Several recent studies have used airplanes and
towers to measure methane in the air and found emissions to be much higher than
EPA estimates, with some as much as 75 percent higher.
Brandt and
his colleagues determined that those measurements were too high, or came from production
areas that weren’t representative of the country as a whole, so they dismissed
the data. But you don’t get to toss out data you don’t like unless you have
very good reason, says Ingraffea.
Another
problem, says Ingraffea, is that the
authors simply assert that the 3 million or so abandoned oil and gas wells scattered
across the nation are properly plugged and therefore probably not leaking. “The
problem with that,” he says, “is that they don’t know where all those abandoned
wells are, so they can’t really measure whether they’re leaking or not.”
Ingraffea
also takes issue with the study’s claim that, if industry could plug up the
leaks, burning gas in power plants would be better for the climate instead of
burning coal. In order to make that claim they stretch out their timeframe to
100 years.
“That’s totally
arbitrary,” says Ingraffea, “and not based on science.” The Intergovernmental
Panel on Climate Change (IPCC) gives us about 20 to 30 years before we approach
a tipping point, Ingraffea explains. “We can’t wait that long to start
decreasing the carbon emissions from fossil fuel.” He adds that using a
hundred-year timeframe is a policy decision that is “…perhaps based on faulty
scientific understanding of the climate change situation in which we find
ourselves or perhaps political wishful thinking.”
Now is a
good time to be reexamining and summarizing previous studies, says Ingraffea.
But it’s premature to draw conclusions, because every year there are new
studies by scientists collecting actual measurements in the air and on the
ground. And the data from these new studies continue to show methane emissions
at rates much higher than previously thought.
Looking at
the big picture, Ingraffea believes the study asks the wrong question. Instead
of trying to pin down an average emission rate of methane, they should be
asking how much risk we are willing to take. “Risk is the key issue of any
policy decision,” says Ingraffea. Sometimes there are bad things that can
happen, but they have little consequence so we live with them – even if they
happen frequently.
“But this
is one
thing with a major consequence, so we have to be conservative in our risk
taking,” says Ingraffea. Using the average value of methane emissions is
inadequate, he says. Policy makers need to peg emission allowances closer to
the lower end – and even then acknowledge the uncertainties surrounding that
level.
“In the
meantime, many of those crucial next 20 years are going by,” Ingraffea warns, “and
we should have already started to reduce all fossil fuel use, not increase it
as this study proposes.”
This article first published in Tompkins Weekly, February 24, 2014.
