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CONSERVATION GROUPS’ COMMENTS <br />UNCOMPAHGRE FIELD OFFICE RMP AND DEIS <br />86 <br />in some cases to improve the accuracy of emission factors used to calculate emissions from a <br />variety of sources;” specifically citing the lack of accuracy in emission factors applied to <br />methane sources.252 A lack of data reliability has resulted in notable variation in methane <br />emissions reporting from year to year. For example, in a Technical Support Document (“TSD”) <br />prepared for EPA’s mandatory GHG reporting rule for the oil and gas sector for 2012, EPA <br />determined that several emissions sources were projected to be “significantly underestimated.”253 <br />EPA thus provided revised emissions factors for four of the most significant underestimated <br />sources that ranged from ten times higher (for well venting from liquids unloading) to as many as <br />3,500 and 8,800 times higher (for gas well venting from completions and well workovers of <br />unconventional wells).254 When EPA accounted for just these four revisions, it more than <br />doubled the estimated GHG emissions from oil and gas production, from 90.2 million metric <br />tons of CO2 equivalent (“MMTCO2e”) to 198.0 MMTCO2e.255 However, these emission <br />estimates are based on an outdated GWP of 21. Using the IPCCs new 100-year GWP for <br />methane of 36, that is 320.5 MMTCO2e, and, considering a 20-year GWP of 87, that is 792.0 <br />MMTCO2e – or, respectively, the equivalent emissions from 90.7 or 224 coal fired power plants <br />that is wasted annually. These upward revisions were based primarily on EPA’s choice of data <br />set, here, having replaced Energy Information Administration (“EIA”) data with emissions data <br />from an EPA and Gas Research Institute (“GRI”) study. In the current year, EPA relied on yet <br />another set of data; this time from an oil and gas industry survey of well data conducted by the <br />American Petroleum Institute (“API”) and the American Natural Gas Alliance (“ANGA”).256 <br />The API/ANGA survey was conducted in response to EPA’s upward adjustments in the previous <br />GHG inventory, noting that “[i]ndustry was alarmed by the upward adjustment,” and focused <br />specifically on emissions from liquids unloading and unconventional gas well completions and <br />workovers.257 Overall, the survey found that revising emissions from these two sources alone <br />would reduce EPA oil and gas methane emissions estimates, which resulted in reported oil and <br />gas production emissions at 100 MMTCO2e pursuant to the EPA’s GHG Reporting Program.258 <br /> <br />To provide a specific example of these differing data sets, EPA previously used an <br />emissions factor of three thousand standard cubic feet (“Mcf”) of gas emitted to the atmosphere <br />per well completion in calculating its GHG inventory. EPA determined that this figure was <br /> 252 Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011, at 1-19 (attached above <br />as Exhibit 122). 253 U.S. Environmental Protection Agency, Greenhouse Gas Emissions Reporting From The <br />Petroleum And Natural Gas Industry Background Technical Support Document, at 8, available <br />at: http://www.epa.gov/climatechange/emissions/subpart/w.html (attached as Exhibit 137). 254 Id. at 9, Table 1; see also Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011 <br />(attached above as Exhibit 122). 255 See EPA, GHG Emissions Reporting at 10, Table 2 (attached above as Exhibit 137). 256 Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2011, at 3-63 (attached above <br />as Exhibit 122). 257 API/ANGA, Characterizing Pivotal Sources of Methane Emissions from Natural Gas <br />Production: Summary and Analysis of API and ANGA Survey Responses, Sept. 2012, at 1 <br />(attached as Exhibit 138). 258 See EPA, Petroleum and Natural Gas Systems: 2011 Data Summary (for 2013 GHG <br />Reporting), at 3 (attached as Exhibit 139).