to some of the most complete calculations available, when we use
natural gas to generate electricity in an average power plant, it
than if we generate the same electricity with coal. If we fully
utilized the natural gas-fired power plants that already exist in this
country, we could
What’s more, primarily because of access to new natural gas reserves,
proved reserves of natural gas recently shot up to
– more than we’ve had on hand at any time since
It’s for these reasons, among others, that many experts and
policymakers have proposed switching
as a “bridge fuel”
to immediately reduce greenhouse gas emissions while we undertake the
much larger and long-term project of ramping up the percentage of our
energy generated from renewables, which is currently about 7 percent.
that renewable energy is hydroelectric and biomass, to
Still, there’s another side to the story: recent research on the
lifecycle of natural gas, from the moment we remove it from the ground
to the moment it’s burned, has challenged assumptions about its
climate-friendliness. At base, economic and policy assumptions about
whether we can use natural gas to reduce emissions in the short-term
depend on what we know about the effects of its extraction and use on
A controversial paper
Methane, the primary constituent of natural gas, is up to 100
a greenhouse gas than carbon dioxide over a 20
year time horizon (though other studies have found it is 72 times more
powerful). As many climate scientists have pointed
out, it’s precisely these
that we want to avoid if we wish to avoid
pushing the climate toward disaster.
Howarth: The Cornell professor's
paper shook the natural gas establishment.
This discussion was heightened last month when Robert Howarth, a
professor of ecology and environmental biology at Cornell University,
published a controversial paper arguing that natural gas from fracking
has a greater net warming effect on the climate than burning coal.
Howarth and his co-authors argue that one of the main problems
methane is that, as a gas, it tends to leak into the atmosphere both
when it’s drilled and when it’s transported. Hydraulic fracturing, or
fracking, is the process by which wells are drilled into shale rock,
then water and a mix of chemicals are injected at high pressure, to
crack or “frack” the deposit, allowing natural gas to escape.
“If you look at the inventory of emissions of human-controlled
methane from the U.S., 25-50 percent of it is from [the use of] natural
gas,” says Howarth.
Capturing “fugitive” gas
Industry has a monetary incentive to eliminate these losses, at
least during the drilling and initial distribution stages, but thus far
it has been slow to do so. Granted, there are barriers to eliminating
leaks. For example, when a new well is being drilled, gas storage
infrastructure must also be built in advance in order to capture the
gas that leaks during the drilling phase. The EPA has studied Reduced
Emission Completions technologies, and concluded that on the average
well, these technologies mean a higher up-front investment, but they pay
3-5 months by capturing gas that would
otherwise be lost. Still, at present they are rarely built.
Howarth came to the conclusion that when we use frack-produced
natural gas to generate electricity, the net effect on the climate is
worse than coal when looked at from the perspective of the next 20
years. (When looked at over the course of the next 100 years, natural
gas comes out ahead of coal, because methane is removed from the
atmosphere more quickly than carbon dioxide.) This distinction is
crucial: as conventional natural gas wells in the U.S. decline as a
proportion of our gas production, more and more
will come from fracked wells.
Howarth’s conclusions have come under fire from both scientists
Science is an iterative process, and Howarth himself admits that
data he used to determine the natural gas lost during the drilling
process were sparse. Unfortunately, they’re the only data available.
The conclusion of scientists like Bill Chameides, Dean of Duke’s
Nicholas School of the Environment, is that we simply
to determine the climatic effect of natural gas from fracking. That
won’t change until academics and industry obtain better measurements of
losses of methane during drilling.
Natural gas key to more renewables
What’s more, because natural gas power plants can be fired up so
quickly, they play a unique role in the world’s electricity production
system — they are activated when supply, as from renewables, is
outstripped by demand.
“I would say that without natural gas, the grid will not be able
manage the variability and intermittency in power output from wind and
solar plants,” says Paulina Jaramillo, a professor of engineering at
As executive director or the RenewElec project, which aims to
increase the proportion of intermittent sources of renewable energy in
the world grid, Jaramillo specializes in thinking about the transition
off fossil fuels. She doesn’t believe we’ll be able to get more solar
and wind on the grid without natural gas, precisely because the only
alternative — storage mechanisms like batteries and demand-side
management — aren’t far enough along.
Howarth believes that in the future, the major drivers of these
human emissions of methane will prove to be use of natural gas,
especially if we come to rely on it for an ever larger portion of our
The good news is that it seems the effects of methane gas can be
limited through action by industry. But the economics of drilling,
mediated by the actions of regulators, will determine just how “clean”
natural gas ultimately proves to be.
Christopher Mims is a contributor to Good, Technology
and The Huffington Post, and is a former editor at Scientific American
and Grist.org. He tweets @mims.
This article first appeared in the Txchnologist
and is reprinted with permission.