96
Concluding its discussion of water resources, the Addendum observes that
“[u]nconventional natural gas production, when conforming to regulatory requirements,
implementing best management practices, and administering pollution prevention concepts, may
have temporary, minor impacts to water resources.”
221
Further, risks may arise when best
practices are not employed: “[I]mproper techniques, irresponsible management, inadequately
trained staff, or site-specific events outside of an operator’s control could lead to significant
impacts on local water resources.”
222
B.
Air Quality
The Addendum discusses air pollutants emitted at different stages of the natural gas
production process. These emissions and their sources are captured in Table 8 below:
Table 8: Source Categories of Airborne Emissions from Upstream Natural Gas Activities
(EPA, 2013)
223
221
Addendum at 19.
222
Id.
223
Id. at 23 (Table 6).
Type of Emissions
Sources of Emissions
Combustion
Emissions
NO
x
and carbon monoxide
(CO) resulting from the
burning of hydrocarbon
(fossil) fuels. Air toxics, PM,
un-combusted VOCs, and CH
4
are also emitted.
Engines, heaters, flares, incinerators,
and turbines.
Vented
Emissions
VOCs, air toxics, and CH
4
resulting from direct releases
to the atmosphere.
Pneumatic devices, dehydration
processes, gas sweetening processes,
chemical injection pumps, compressors,
tanks, well testing, completions, and
workovers.
Fugitive
Emissions
VOCs, air toxics, and CH
4
resulting from uncontrolled
and under-controlled
emissions.
Equipment leaks through valves,
connectors, flanges, compressor seals,
and related equipment and evaporative
sources including wastewater treatment,
pits, and impoundments.
97
The Addendum describes the existing regulatory framework relating to such emissions, as well as
the U.S. Environmental Protection Agency’s (EPA) 2012 New Sources Performances Standards
for hydraulically fractured natural gas wells
224
and EPA’s 2013 update to those standards covering
storage tanks.
225
The Addendum also summarizes the existing literature on each significant
category of air pollutant and describes the potential contribution of oil and gas production
activities to ground-level ozone pollution and reduced visibility in sensitive areas.
The Addendum concludes its discussion of air quality by stating that natural gas
development leads to both short- and long-term increases in local and regional air emissions,
especially methane, VOCs, and hazardous air pollutants. According to the Addendum, the
intermittent nature of air emissions from sources such as wells makes it difficult to analyze
impacts at the regional level. As more data become available, a better understanding of trends in
local and regional air quality and potential impacts may emerge.
226
C.
GHG Emissions
Separate from the LCA GHG Report described below, the Addendum includes a
discussion of GHG emissions associated with unconventional natural gas production— principally
methane and carbon dioxide. The Addendum describes the nature of GHG emissions from each
phase of the production process, including: well drilling and completion; gas production; well re-
completions, workovers, and maintenance; gas processing; and gas transmission and storage.
The Addendum also summarizes regulations affecting GHG emissions from upstream
natural gas activity. As in the air quality section, the Addendum discusses EPA’s 2012 New
Source Performance Standards regulations. The Addendum also describes EPA’s publication in
224
Id. at 20-22.
225
Id. at 22.
226
Id. at 32.
98
April 2014 of five technical white papers on potentially significant sources of emissions in the
oil and gas sector, including completions and ongoing production of hydraulically fractured oil
wells, compressors, pneumatic valves, liquids unloading, and leaks.
227
EPA stated that it will
use these white papers, along with input from peer reviewers and the public to determine how
best to pursue emissions reductions from these sources, possibly including the development of
additional regulations.
228
Finally, the Addendum summarizes the existing literature estimating GHG emissions and
methane leakage rates from the upstream natural gas industry, noting that most studies suggest that
“emissions of GHGs from the upstream industry are of similar magnitude for both conventional
and unconventional sources.”
229
D.
Induced Seismicity
The Addendum provides information on induced seismicity across various types of energy
resource activities, namely the production of natural gas, gas condensates, and oil from currently
targeted unconventional plays. More specifically, it provides greater detail about the potential for
induced seismicity from hydraulic fracturing and wastewater disposal via injection, which is one
method of disposing of produced water. Because the duration of injection of hydraulic fracturing
fluids is generally minutes or hours and the quantity of injected fluid is relatively low, the
Addendum states that “the probability of injecting enough fluid into a natural fault to trigger a felt
earthquake is low.”
230
By contrast, the Addendum states that the “incidence of felt earthquakes is
higher for wastewater disposal via wastewater injection wells because a large volume of water is
227
Addendum at 22 ( citing U.S. Envtl. Prot. Agency, Office of Air Quality Planning & Standards,
White Papers on
Methane and VOC Emissions, available at: http://www.epa.gov/airquality/oilandgas/whitepapers.html) (released
April 15, 2014).
228
Id. at 44.
229
Id. at 40.
230
Id. at 51.
Dostları ilə paylaş: |