THE CASE AGAINST HYDROFRACKING - Hydrofracking: What Everyone Needs to Know - page 65

What Are “Fugitive Emissions”?
As we've seen, once a well has undergone hydraulic fracturing, natural gas re-
leased from shale flows naturally up the borehole to the surface, where most of it
is captured and put to use. But some of this gas, most of which is methane, escapes
into the atmosphere. These leaks are called “fugitive emissions.”
Methane can escape accidentally, through broken pipes, valves, or other equip-
ment (diesel- or natural gas-powered compressors, drill rigs, pumps). A 2009 re-
port in Pipeline and Gas Journal notes that while old, cast-iron pipes make up only
3 percent of US gas mains, they are responsible for most of the leaks—32 percent
of methane emissions—from the natural gas distribution system. In 2012, some
3,300 gas leaks were discovered in Boston alone, according to a report in Environ-
mental Pollution . 79
Methane is sometimes released on purpose—when it is vented or not fully
burned during flaring—in the refining process, and when being piped into homes
or businesses. According to one report, leaks in Russian pipelines account for 0.6
percent of the natural gas transported. 80
Fugitive emissions of methane in particular are hard to measure, and researchers
disagree on the numbers. The EPA has estimated methane leaks at a rate of 2.3 per-
cent of total production. But a recent study in Colorado and Utah found leakage
rates of 4 percent and 9 percent, respectively. 81 The new study—conducted by the
National Oceanic and Atmospheric Association and the University of Colorado at
Boulder—offers only a “snapshot” of a specific location on a specific day, but if
the true figure is at the upper end of the scale, opponents argue, natural gas is actu-
ally not cleaner than other fuels.
This question challenges one of the central rationales for promoting natural
gas—that it burns cleaner than other fossil fuels—and, not surprisingly, has led to
a rancorous dispute.
The previously mentioned 2011 methane study issued by Robert W. Howarth
and colleagues at Cornell concluded that “3.6 percent to 7.9 percent of the methane
from shale-gas production escapes to the atmosphere in venting and leaks over the
lifetime of a well.” 82 This represents up to double the amount from convention-
al gas wells. If Howarth is correct, shale gas would be more polluting than oil
or coal. But Howarth's study has been heavily criticized by the energy industry,
and there are those who disagree with his methodology, including his Cornell col-
league Lawrence Cathles, who called the study “seriously flawed.” 83 In response,