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transport distance, as illustrated by Figures 4-7 and 4-8 of NETL’s Life Cycle Analysis of Natural
Gas Extraction and Power Generation, shows that the doubling (i.e., a 100% increase) of natural
gas pipeline transport distance increases the upstream GHG emissions from natural gas by 30%.
When this upstream sensitivity is applied to the life cycle boundary of the LCA GHG Report, an
additional 100 miles beyond the LNG import terminal increases the life cycle GHG emissions for
the LNG export scenarios by 0.8%, and an additional 500 miles beyond the LNG import terminal
increases the life cycle GHG emissions for the LNG export scenarios by 4% (using 100-year
GWPs as specified by the IPCC Fifth Assessment Report). Although this parameter
modification changes the results of the LCA slightly, it does not change the conclusions of the
LCA GHG Report.
4.
Data Quality for LNG Infrastructure, Natural Gas Extraction, and Coal
Mining
a.
Comments
Several commenters, including API, Concerned Citizens, and Sierra Club, commented on
whether the data used in the LCA GHG Report is current and fully representative of the natural
gas industry. In particular, API asserts that NETL’s model is representative of inefficient
liquefaction technologies that overstate the GHG emissions from the LNG supply chain, coal
data that understates the methane emissions from coal mines, and natural gas extraction data that
mischaracterizes “liquids unloading” practices.
256
API proposes the use of newer data for both
256
For purposes of this term, we refer to EPA’s description of “liquids unloading” as follows: “In new gas wells,
there is generally sufficient reservoir pressure to facilitate the flow of water and hydrocarbon liquids to the surface
along with produced gas. In mature gas wells, the accumulation of liquids in the well can occur when the bottom
well pressure approaches reservoir shut-in pressure. This accumulation of liquids can impede and sometimes halt
gas production. When the accumulation of liquid results in the slowing or cessation of gas production (i.e., liquids
loading), removal of fluids (i.e., liquids unloading) is required in order to maintain production. Emissions to the
atmosphere during liquids unloading events are a potentially significant source of VOC and methane emissions.”
U.S. Envtl. Prot. Agency, Office of Air Quality Planning & Standards, Oil & Natural Gas Sector Liquids Unloading
Processes, Report for Oil & Gas Sector Liquids Unloading Processes Review Panel, at 2 (April 2014), available at:
http://www.epa.gov/airquality/oilandgas/pdfs/20140415liquids.pdf.
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liquefaction terminals in the United States and methane emission factors from unconventional
natural gas extraction and coal mining. Concerned Citizens argue that the LCA GHG Report
does not clearly identify its source of data for estimates of loss related to LNG production,
shipping, and regasification, as well as the basis for estimates of pipeline losses from Russia.
Sierra Club points to inaccurate referencing of EPA’s Subpart W report, which was the basis for
many of NETL’s emission factors for natural gas extraction.
b.
DOE/FE Analysis
(1)
Liquefaction Data
API points to newer data for liquefaction facilities that have higher efficiencies than the
liquefaction process in the LCA GHG Report. API points to the GHG intensities of the
liquefaction facilities proposed by Sabine Pass, Cameron LNG, and FLEX, each of which has
been granted one or more non-FTA LNG export orders by DOE/FE ( see infra § XII.D).
According to API, these proposed facilities will produce 0.26, 0.29, and 0.12 tonnes of CO
2
e per
tonne of LNG, respectively. The majority of a liquefaction facility’s energy is generated by
combusting incoming natural gas, so the GHG intensity of a liquefaction facility is directly
related to its efficiency. As API correctly points out, the LCA model assumes a GHG intensity
of 0.44 tonnes of CO
2
e per tonne of LNG; this GHG intensity is representative of a facility that
consumes 12% of incoming natural gas as plant fuel.
257
The above GHG intensities and liquefaction efficiencies are not life cycle numbers, but
represent only the gate-to-gate operations of liquefaction facilities, beginning with the receipt of
processed natural gas from a transmission pipeline and ending with liquefied natural gas ready
257
NETL (2010). NETL Life Cycle Inventory Data – Unit Process: LNG Liquefaction, Operation. U.S. Department
of Energy, National Energy Technology Laboratory. Last Updated: May 2010 (version 01); available at:
http://www.netl.doe.gov/File Library/Research/Energy Analysis/Life Cycle
Analysis/UP_Library/DS_Stage1_O_LNG_Liquefaction_2010-01.xls.
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for ocean transport. As illustrated by Figures 6-1 and 6-2 in the LCA GHG Report (reproduced
as tables herein), liquefaction accounts for approximately 10% of the life cycle GHG emissions
of U.S. LNG used for electric power generation in Europe and Asia. A doubling of liquefaction
efficiency (thus achieving a GHG intensity comparable to the average of the Sabine Pass,
Cameron, and Freeport facilities) would lead to a 6% reduction in the feed rate of natural gas to
the liquefaction plant.
258
This feed rate reduction would also reduce natural gas extraction,
processing, and transmission emissions by 6%, but would not affect the processes downstream
from liquefaction (ocean tankers, power plants, and electricity transmission networks). Applying
the increased liquefaction efficiency and the 6% reduction in feed rate to the results of the LCA
GHG Report would reduce the life cycle GHG emissions for LNG export scenarios by only 1.5%
(using 100-year GWPs as stated in the IPCC Fifth Assessment Report). Increasing liquefaction
efficiency may significantly reduce the emissions from one point in the supply chain, but it does
not change the conclusions of the LCA.
(2)
Natural Gas Methane Data
API and Concerned Citizens criticize the quality of data that DOE/NETL uses for natural
gas extraction. API’s concern is that NETL overstates the GHG emissions from unconventional
well completion. API compares NETL’s emission factor for unconventional well completions
(9,000 Mcf of natural gas/episode) to the emission factor that EPA states in its 2014 GHG
inventory (approximately 2,500 Mcf of natural gas/episode). EPA revised its unconventional
completion emission factor between its 2013 and 2014 inventory reports,
259
after NETL’s model
had been finalized and during the time that NETL was completing the LCA GHG Report. These
258
See id.
259
U.S. Envtl. Prot. Agency, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2012, available at:
http://www.epa.gov/climatechange/Downloads/ghgemissions/US-GHG-Inventory-2014-Main-Text.pdf.
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