Technical Support Document

for Greenhouse Gas Emissions Thresholds Evaluation

Air Quality Policy Division

Office of Air Quality Policy and Standards

U.S. Environmental Protection Agency

March 29, 2010

Table of Contents

Page

  TOC \o "1-3" \h \z \u    HYPERLINK \l "_Toc257110003"  1.  Purpose	  PAGEREF _Toc257110003 \h  1

  HYPERLINK \l "_Toc257110004"  2.  Overview	  PAGEREF _Toc257110004 \h  1

  HYPERLINK \l "_Toc257110005"  3.  Emissions-based Threshold Analysis	  PAGEREF _Toc257110005 \h  2

  HYPERLINK \l "_Toc257110006"  3.1  General Description of Overall Approach	  PAGEREF _Toc257110006 \h  2

  HYPERLINK \l "_Toc257110007"  3.1.1  Threshold Levels	  PAGEREF _Toc257110007 \h  2

  HYPERLINK \l "_Toc257110008"  3.1.2  Greenhouse Gases	  PAGEREF _Toc257110008 \h  3

  HYPERLINK \l "_Toc257110009"  3.1.3  Source Sectors	  PAGEREF _Toc257110009 \h  4

  HYPERLINK \l "_Toc257110010"  3.1.4  Potential to Emit Methodology	  PAGEREF _Toc257110010 \h  5

  HYPERLINK \l "_Toc257110011"  3.1.5  New and Modified Sources	  PAGEREF _Toc257110011 \h  6

  HYPERLINK \l "_Toc257110012"  3.2  Threshold Summary Results	  PAGEREF _Toc257110012 \h  6

  HYPERLINK \l "_Toc257110013"  3.3  Electricity Generating Sector	  PAGEREF _Toc257110013 \h  9

  HYPERLINK \l "_Toc257110014"  3.4  Industrial Sector	  PAGEREF _Toc257110014 \h  11

  HYPERLINK \l "_Toc257110015"  3.4.1  Data Sources	  PAGEREF _Toc257110015 \h  14

  HYPERLINK \l "_Toc257110016"  3.4.2  Potential to Emit	  PAGEREF _Toc257110016 \h  14

  HYPERLINK \l "_Toc257110017"  3.4.3  Methodology for New Units	  PAGEREF _Toc257110017 \h  14

  HYPERLINK \l "_Toc257110018"  3.5  Methodology for Existing Unspecified Industrial Stationary Combustion Source

Category Emissions	  PAGEREF _Toc257110018 \h  15

  HYPERLINK \l "_Toc257110019"  3.6  Methodology for Existing Specific Industrial Sectors Considering Combustion,

Process, and Fugitive Emissions	  PAGEREF _Toc257110019 \h  17

  HYPERLINK \l "_Toc257110020"  3.6.1  Adipic Acid Production	  PAGEREF _Toc257110020 \h  17

  HYPERLINK \l "_Toc257110021"  3.6.2  Aluminum Production	  PAGEREF _Toc257110021 \h  19

  HYPERLINK \l "_Toc257110022"  3.6.3  Ammonia Production	  PAGEREF _Toc257110022 \h  21

  HYPERLINK \l "_Toc257110023"  3.6.4  Cement Production	  PAGEREF _Toc257110023 \h  22

  HYPERLINK \l "_Toc257110024"  3.6.5  Electronic Production	  PAGEREF _Toc257110024 \h  24

  HYPERLINK \l "_Toc257110025"  3.6.6  Ethanol Production	  PAGEREF _Toc257110025 \h  25

  HYPERLINK \l "_Toc257110026"  3.6.7  Ferroalloy Production	  PAGEREF _Toc257110026 \h  27

  HYPERLINK \l "_Toc257110027"  3.6.8  Food Processing	  PAGEREF _Toc257110027 \h  29

  HYPERLINK \l "_Toc257110028"  3.6.9  Glass Manufacturing	  PAGEREF _Toc257110028 \h  30

  HYPERLINK \l "_Toc257110029"  3.6.10  HCFC-22 Production	  PAGEREF _Toc257110029 \h  31

  HYPERLINK \l "_Toc257110030"  3.6.11  Hydrogen Production	  PAGEREF _Toc257110030 \h  33

Table of Contents (cont.)

Page

  HYPERLINK \l "_Toc257110031"  3.6.12  Iron and Steel Production	  PAGEREF _Toc257110031 \h  34

  HYPERLINK \l "_Toc257110032"  3.6.13  Lead Production	  PAGEREF _Toc257110032 \h  37

  HYPERLINK \l "_Toc257110033"  3.6.14  Lime	  PAGEREF _Toc257110033 \h  38

  HYPERLINK \l "_Toc257110034"  3.6.15  Magnesium Production and Processing	  PAGEREF _Toc257110034 \h  39

  HYPERLINK \l "_Toc257110035"  3.6.16  Nitric Acid Production	  PAGEREF _Toc257110035 \h  41

  HYPERLINK \l "_Toc257110036"  3.6.17  Petrochemical Production	  PAGEREF _Toc257110036 \h  42

  HYPERLINK \l "_Toc257110037"  3.6.18  Petroleum Refineries	  PAGEREF _Toc257110037 \h  44

  HYPERLINK \l "_Toc257110038"  3.6.19  Phosphoric Acid Production	  PAGEREF _Toc257110038 \h  46

  HYPERLINK \l "_Toc257110039"  3.6.20  Pulp and Paper Manufacturing	  PAGEREF _Toc257110039 \h  47

  HYPERLINK \l "_Toc257110040"  3.6.21  Silicon Carbide Manufacturing	  PAGEREF _Toc257110040 \h  48

  HYPERLINK \l "_Toc257110041"  3.6.22  Soda Ash Production	  PAGEREF _Toc257110041 \h  50

  HYPERLINK \l "_Toc257110042"  3.6.23  Titanium Dioxide Production	  PAGEREF _Toc257110042 \h  51

  HYPERLINK \l "_Toc257110043"  3.6.24  Zinc Production	  PAGEREF _Toc257110043 \h  52

  HYPERLINK \l "_Toc257110044"  3.7  Energy Sector	  PAGEREF _Toc257110044 \h  53

  HYPERLINK \l "_Toc257110045"  3.7.1  Oil and Gas Systems	  PAGEREF _Toc257110045 \h  53

  HYPERLINK \l "_Toc257110046"  3.7.2  Underground Coal Mining	  PAGEREF _Toc257110046 \h  54

  HYPERLINK \l "_Toc257110047"  3.8  Waste Sector	  PAGEREF _Toc257110047 \h  57

  HYPERLINK \l "_Toc257110048"  3.8.1  Landfills	  PAGEREF _Toc257110048 \h  57

  HYPERLINK \l "_Toc257110049"  3.8.2  Municipal Solid Waste Combustors	  PAGEREF _Toc257110049 \h  59

  HYPERLINK \l "_Toc257110050"  3.9  Agriculture (Stationary Fuel Combustion)	  PAGEREF _Toc257110050 \h  60

  HYPERLINK \l "_Toc257110051"  3.10  Commercial Stationary Fuel Combustion	  PAGEREF _Toc257110051 \h  62

  HYPERLINK \l "_Toc257110052"  3.11  Residential Buildings	  PAGEREF _Toc257110052 \h  65

  HYPERLINK \l "_Toc257110053"  3.11.1  Single-Family Homes	  PAGEREF _Toc257110053 \h  66

  HYPERLINK \l "_Toc257110054"  3.11.2  Multi-Family Residential Buildings	  PAGEREF _Toc257110054 \h  67

  HYPERLINK \l "_Toc257110055"  References	  PAGEREF _Toc257110055 \h  72

  HYPERLINK \l "_Toc257110056"  Appendix A	  PAGEREF _Toc257110056 \h  77

  HYPERLINK \l "_Toc257110057"  Appendix B	  PAGEREF _Toc257110057 \h  78

Technical Support Document for Permit Thresholds for Greenhouse Gases

1.  Purpose

	The purpose of this document is to provide the background information that was used to support EPA's decision process on evaluating and selecting greenhouse gas (GHG) major source applicability thresholds for Prevention of Significant Deterioration (PSD) and Title V permitting for EPA’s final rule “Prevention of Signficant Deterioration and Title V Greenhouse Gas Tailoring Rule”.  The document describes the analysis used to estimate the number of existing and new facilities (e.g., industrial plant or commercial building) that would exceed different GHG emission threshold levels.  The document also summarizes the results of this analysis for each sector.  The results of this analysis served as one of the fundamental bases for evaluating administrative burdens at both existing permitting thresholds and for evaluating and selecting proposed alternative permitting thresholds to address administrative necessity concerns.

2.  Overview

	In order to support EPA's assessment of the administrative burden created by adding GHGs to existing Prevention of Significant Deterioration (PSD) and Title V permitting programs, it was necessary to develop information on the number of affected facilities at both the current permitting major source thresholds (generally, 100 tons per year for Title V and 100 or 250 tons per year for PSD depending on the source category classification) and at alternative higher thresholds.  An affected facility would be one who's annual emissions of the GHG equal or exceed the major source threshold being evaluated.

	Eight threshold levels ranging from 100 to 100,000 tons per year of GHG emissions were evaluated.  Some of the alternative thresholds evaluated are the same as ones (e.g., 25,000 tons per year CO2-equivalents) considered in previous studies and in support of EPA's proposed and final GHG mandatory reporting rules (GHG MRR, 74 FR 68, pp. 16447 – 16731 and 74 FR 209, pp. 56260-56519, respectively).  One key difference between the emissions data developed for this analysis and the emissions data developed to support the proposed GHG MRR is that this analysis is based on a facility's "potential to emit" (PTE) while the proposed GHG reporting rule was based on "actual" emissions (i.e., the emissions a facility actually emits in a given year).  PTE is defined as the maximum capacity of a stationary source to emit a pollutant under its physical and operational design, including certain legal limitations, for example, on emissions or hours of operation.  NSR and Title V programs both use PTE for defining major sources.  The end result is generally that more facilities will exceed a given threshold on a PTE basis than on an actual basis.  This is an important differentiation in terms of both evaluating the thresholds under this rule and when comparing the results to other threshold analysis, such as the supporting data for the EPA's GHG MRR.

	Although the primary focus of this analysis was on the potential administrative burden associated with different GHG permitting emission levels as represented in terms of number of facilities potentially subject to permitting, information on GHG emissions from affected facilities was also collected to assess the relative coverage of national stationary source GHG emissions at the different threshold levels.  While the environmental impact associated with the different GHG permitting levels was not used as the basis for the GHG applicability thresholds identified in the final GHG tailoring rule, the information on national emissions coverage provides a useful measure to consider the potential scope of the proposed alternative thresholds, their coverage of key GHG emission source categories, and whether they promote the environmental purposes of the PSD and Title V programs.

3.  Emissions-based Threshold Analysis

3.1  General Description of Overall Approach

This section presents a general description of the overall approach EPA used to evaluate a range of permitting thresholds in terms of the number of sources affected, and amount of emissions covered.

EPA made use of earlier analyses performed to develop emission thresholds for the proposed and final GHG MRR, or used the same data sources when additional analyses were required.  EPA did not conduct primary research for this analysis, but instead relied on published research and publicly available government data, such as EPA's eGRID database of electric generating source emissions, Economic and Housing Census data, and Energy Information Agency (EIA) data on energy consumption.

3.1.1  Threshold Levels

	EPA evaluated eight different GHG emission thresholds:

	GHG Thresholds

	(tons per year)

100

250

1,000

5,000

10,000

25,000

50,000

100,000

The first two thresholds are the current Clean Air Act major source criteria pollutant thresholds for the federal operating permit program under Title V (generally, 100 tpy for major source applicability), and the PSD construction permit program under Title I.  Under PSD, a "major stationary source" is any source belonging to a specified list of 28 source categories which emits or has a PTE of 100 tpy or more, or any other source type which emits or has the potential to emit such pollutants in amounts equal to or greater than 250 tpy.

The six additional thresholds cover the range of thresholds evaluated for the proposed GHG MRR, and add two additional thresholds at 5,000 and 50,000 tons per year.  Like the Clean Air Act, the permit thresholds are based on U.S. short tons (tons) instead of metric tons (mtons).

There is a three-orders-of-magnitude range in the thresholds which reflects the much higher quantity of GHG emissions compared to criteria pollutant emissions from the primary source of GHG emissions, fossil fuel combustion.  For example, an uncontrolled natural gas-fired boiler that emits 100 tons of NOx annually would at the same time emit about 100,000 tons of CO2.

	The threshold analysis of source counts and emissions was done on a "potential to emit" basis, because that is the basis that is relevant for the permitting requirements under PSD and title V.  Potential emissions (in short tons) from each source were evaluated against the threshold levels in order to determine whether or not a source would be included in the threshold count.  When a source was identified as being covered by a given threshold level, the actual emissions from that source were included to determine the emissions covered by the threshold.  In other words, where summary tables present "Tg GHG Emissions Covered per Year" these are the actual emissions that would be covered by the threshold level, given the source count arrived at considering potential to emit emission levels.

3.1.2  Greenhouse Gases

EPA evaluated emissions of the major GHGs that are directly emitted by human activities at the eight threshold levels.  The GHGs evaluated are shown below in Table 1.  For purposes of this analysis emissions were evaluated on both an individual GHG mass basis and CO2-equivalent basis (CO2e).  CO2e normalizes the different heat trapping capacities of the different GHGs to that of CO2.  A quantity of a GHG is converted to a CO2e basis by multiplying the mass of the compound emitted by its Global Warming Potential (GWP).  The GWP is a metric that incorporates both the heat-trapping ability and atmospheric lifetime of each GHG relative to CO2.

Table 1

Major GHGs Directly Emitted by Human Activities

Greenhouse Gas	Chemical Formula or Acronym	Global Warming Potential (GWP)*

Carbon dioxide	CO2	1

Methane	CH4	21

Nitrous oxide	N2O	310

Perfluorocarbons	PFCs	Varies by compound

Hydrofluorocarbons	HFCs	Varies by compound

Sulfur hexafluoride	SF6	23,900

*  GWP values as codified in the EPA’s final GHG mandatory reporting rule:  Table A-1 to Subpart A of Part 98 – Global Warming Potentials, FR, Vol.74, No. 209, p. 56395.

	Sector descriptions contained in this document include a discussion of GHGs evaluated for each sector.  If the analysis included more than one GHG, the description includes gas-specific counts as well as a CO2e count.  The threshold analyses for stationary fossil fuel combustion were simplified by excluding CH4 and N2O emissions, because CO2 comprises over 99 percent of GHG emissions from fossil fuel combustion.

3.1.3  Source Sectors

In this analysis EPA evaluated the same range of stationary source types with direct GHG emissions as identified in the proposed and final GHG MRR.  The proposed GHG MRR source categories were based on a comprehensive review of all U.S. source categories with GHG emissions, to include the categories that emit the most significant amount of GHG emissions.  The stationary sources evaluated in this analysis can be grouped in the sectors shown below:

●	Electricity Generation (facilities with fossil fuel-fired electric generating units);

●	Industry (range of industries with process and combustion GHG emissions);

●	Energy (oil and gas extraction, transport, and processing; underground coal mining);

●	Waste Treatment (landfills and municipal solid waste incinerators);

●	Agriculture (stationary fuel combustion);

●	Commercial (stationary fuel combustion); and

●	Residential (stationary fuel combustion).

	A number of direct emission source types included in the GHG MRR analysis were not included in the potential to emit analysis because the GHG emissions from these sources were primarily fugitive emissions.  Fugitive emissions are emissions which are not released, or could not be reasonably released, through a猠慴正漠⁲敶瑮唠摮牥琠敨倠䑓爠汵獥畦楧楴敶 攠業獳潩獮愠敲漠汮⁹湩汣摵摥椠潰整瑮慩潴攠業 ⁴獥楴慭整⁳晩琠敨猠畯捲獩漠敮漠㠲氠獩整卐 ⁄潳牵散挠瑡来牯敩⹳†硅汣摵摥映杵瑩癩浥獩楳湯 ⁳潳牵散⁳牡楬瑳摥戠汥睯ഺ

●	Electrical equipment SF6 emissions;

●	Wastewater treatment plants not associated with one of 28 listed PSD source categories (combustion is captured in the commercial sector analysis); and

●	Agricultural manure management.

3.1.4  Potential to Emit Methodology

As noted earlier, the potential to emit (PTE) is the amount of emissions that can be emitted from a source operating at full capacity.  The annual PTE is based on operation at full equipment capacity, 24 hours per day, 365 days per year (8,760 hours per year).  For example, if a boiler has a maximum rated heat input capacity of ten million Btu per hour, the annual PTE for that boiler is the amount of emissions from burning 87,600 million Btu of fuel:

10 mmBtu/hr x 8,760 hrs/yr = 87,600 mmBtu/yr

Capacity information and annual GHG emissions were available for some of the source categories from analyses performed to support the GHG MRR.  In some cases the supporting analyses had already calculated GHG emissions on a full capacity basis, in which case EPA directly used those estimates as PTE estimates.  Alternatively, some data from the supporting analysis estimated actual annual emissions using a baseline year.  If capacity and baseline year production information was provided in the supporting data, EPA adjusted the source actual emissions estimate by the ratio of annual capacity to baseline production to estimate PTE.  If capacity information was not available, EPA used capacity factors from other data sources to adjust actual emission estimates to PTE estimates.  These capacity factors add varying uncertainty to the PTE estimate.  Detailed descriptions of the different PTE calculation methodologies are included in the source descriptions in the following section.

	Removal by pollution control equipment was considered in the PTE estimates, though control equipment removal was relevant in only a few cases (thermal oxidation of HPCs and CH4).  Also, as noted earlier, fugitive emissions, were only included in the PTE estimates if the source was one of the 28 listed PSD source categories.  For example, fugitive CH4 emissions from oil and gas transmission stations were not included in CH4 or CO2e emissions when comparing to the different thresholds, but were included for iron and steel plants.

3.1.5  New Construction

The source population data from the analyses supporting the GHG MRR, and other data sources provide information on existing sources and their emissions.  The PSD and title V program requirements and applicability determinations, however, also apply to newly constructed sources.

The general approach for estimating the annual number of newly constructed sources was to apply growth rates in the number of units or facilities in a source category to the number of existing facilities at the different thresholds.  Growth rates were available from a variety of sources including Economic Census data, EIA energy survey data, and various EPA regulatory impact analyses and information collection requests which require source population estimates.  In some cases there was sufficient information to distribute new sources to different thresholds based on emission information specific to the new sources (electric generating, municipal solid waste combustors, and commercial stationary fuel combustion).  Otherwise EPA assumed the same size and threshold distribution for new units as for existing units.  For example, if the annual growth rate in a category was one percent, the number of existing facilities above a threshold were multiplied by the fractional growth rate to estimate the number of new facilities at that threshold per year.

EPA did not develop estimates for modifications to exsiting sources (which can be potentially subject to PSD requirements) as part of this threshold study;  estimates for modifications were prepared under a separate burden analysis prepared for the final GHG tailoring rule and located in the final docket for the rulemaking.

3.2  Threshold Summary Results

The resulting counts of affected stationary source facilities and the amount of actual GHG emissions covered at different PTE thresholds for all sectors are shown in the tables below.  GHG emissions covered at each threshold are in Tg, which is equivalent to million metric tons.  SI units were used for the covered emissions to be consistent with the EPA’s official U.S. GHG Inventory so that comparions could be made to the inventory in terms of emissions coverage at different applicability thresholds.  The complete data for the sectors and subsectors are provided in supporting spreadsheets that accompany this report.  These spreadsheets are identified in Appendices A and B.

Table 2

CO2e Threshold Summary -- All Stationary Source Sectors

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	6,118,252	67,469	3,867

250	1,079,483	19,755	3,786

1,000	302,863	4,430	3,723

5,000	59,140	549	3,622

10,000	30,341	313	3,564

25,000	16,564	140	3,493

50,000	9,980	96	3,387

100,000	5,326	72	3,267

Table 3

CO2 Threshold Summary -- All Stationary Source Sectors

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

100	6,113,861	67,469	3,651

250	1,075,078	19,755	3,570

1,000	298,527	4,430	3,513

5,000	55,313	549	3,413

10,000	26,836	313	3,357

25,000	13,637	139	3,293

50,000	8,109	96	3,212

100,000	4,226	72	3,114

Table 4

CH4 Threshold Summary -- All Stationary Source Sectors

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CH4 Emissions Covered

(Tg per year)

100	4,201	0	7.807

250	3,851	0	7.759

1,000	2,887	0	7.321

5,000	1,042	0	4.740

10,000	466	0	3.697

25,000	138	0	2.234

50,000	34	0	1.185

100,000	3	0	0.211

Table 5

N2O Threshold Summary -- All Stationary Source Sectors

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	N2O Emissions Covered

(Tg per year)

100	47	0	0.074

250	46	0	0.074

1,000	31	0	0.068

5,000	5	0	0.022

10,000	0	0	0

25,000	0	0	0

50,000	0	0	0

100,000	0	0	0

Table 6

High GWP Gases Threshold Summary -- All Stationary Source Sectors

GHG	GHG Threshold*

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	GHG Emissions Covered

(Tg per year)

HFC	100	3	0	0.001

HFC	250	3	0	0.001

HFC	1,000	1	0	0.001

HFC	5,000 and above	0	0	0

PFC	100 and above	0	0	0

SF6	100 and above	0	0	0

*  Where a threshold is not listed for a particular GHG, threshold counts for that threshold and any higher thresholds can be assumed to be zero.

3.3  Electricity Generating Sector

Data Sources

	The latest version of EPA's eGRID database (2006) was used to estimate the PTE of electricity generating facilities and counts of units above the different emission thresholds.  The eGRID database includes year 2004 characteristics, operating information, and annual emissions (including CO2) for U.S. facilities that have a generation capacity greater than one MW, and sell electric power to the grid.

	A facility's PTE was estimated based on the eGRID generator table.  The generator table, which is based on the 2004 EIA form 860 database, provides prime mover, generator nameplate capacity, and primary energy source (fuel type) for each generator down to 0.1 MW.  To calculate PTE, we combined the nameplate capacity and primary fuel for each of the fossil-fired units with average fuel based prime mover heat rates (Btu/kWh) published by EIA (EIA, 2007).

Table 7

EGU Prime Mover Heat Rates

(EIA Electric Power Annual, Table A7, 2007)

Prime Mover	Fuel	Average Heat Rate (Btu/kWh)

Steam turbine	Coal	10,114

	Gas	10,466

	Oil	10,400

Simple

combustion turbine	Gas	11,459

	Oil	13,216

Combined cycle

combustion turbine	Gas	7,445

	Oil	11,015

Internal

combustion engine	Gas	9,923

	Oil	10,149

	The eGRID database includes cogeneration plants and generating units at industrial plants that primarily supply electric power and steam to a host facility.  We eliminated these units from the electric generation facility population based on North American Industry Classification System (NAICS) code, so that the only facilities included were facilities with a NAICS code beginning with 22 (Utilities).

	The generator-nameplate-heat-rate approach potentially underestimates PTE for cogeneration plants, where a portion of the burner heat input provides useful thermal energy in addition to electric output.  This potential to underestimate PTE affects 321 of 2,237 or 14 percent of facilities evaluated.

Methodology for Existing Facilities

	Fuel combustion was the only source of GHG emissions considered for the electricity generation sector.  From the eGRID and EIA information EPA calculated a maximum annual fuel heat input based on 8,760 hours of operation for the combustors associated with the generator.  This calculated maximum annual heat input was used with fuel combustion emission factors from the GHG MRR for the primary fuel, to calculate the facility PTE.  The calculations covered 10,487 fossil fuel-fired generators with nameplate capacities down to 0.1 MW or 100,000 kW.

	EPA also did not evaluate fugitive CH4 emissions from facility coal piles.  Fossil fuel-fired steam electric plants with heat input greater than 250 mmBtu/hr heat input are one of the 28 listed PSD source categories that include fugitive emissions when calculating PTE.  However, the CO2 PTE from combustion alone for this size facility is about 225,000 tons per year.  This is well over all of the emission thresholds considered in this analysis without consideration of the contribution of fugitive CH4.

New Units

	The eGRID generator table includes an online year field.  To determine the number of new units per year at different thresholds EPA counted generators online each year and totaled the emissions associated with those generators at the facility level over the 15-year period from 1990 through 2004.  Counts were made of the number of these facilities over the different PTE thresholds, and averaged over the 15 years to arrive at the number of new or modified facilities per year.

Threshold Summary

	The table below shows the facilities and emissions covered at the different emission thresholds based on the described methodology.  There were a total of 2,237 facilities in the electric generation population, so all facilities and all emissions are covered up to the 5,000 ton PTE threshold.  Almost all emissions (99.9 percent), and about 75 percent of facilities are covered at the highest 100,000 ton PTE threshold.

Table 8

CO2 Threshold Summary Results -- Electricity Generating Sector

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2Emissions Covered

(Tg per year)

100	2,237	93	2,373

250	2,237	93	2,373

1,000	2,237	93	2,373

5,000	2,237	91	2,373

10,000	2,195	86	2,373

25,000	2,076	73	2,373

50,000	1,911	64	2,373

100,000	1,721	60	2,371

3.4  Industrial Sector

The industrial sector comprises establishments engaged in the mechanical, physical, or chemical transformation of materials, substances, or components into new products, and specifically includes businesses classified in Sectors 31 – 33 according to the North American Industry Classification System (NAICS).  Industrial source greenhouse gases result from manufacturing processes as well as combustion processes.  Because there is a great deal of variability within the sector, this technical support document includes industry-specific discussions after a general sector overview.

For the industrial sector, EPA considered the six individual greenhouse gases separately, and also prepared an analysis considering CO2e.  In preparation of the GHG MRR, EPA identified 23 industrial sectors where the GHG emissions were significant; these sectors are listed in Table 9.

Table 9

Industrial Sectors and GHG Emissions

NAICS Code	Industrial Sector	CO2	CH4	N2O	SF6	HFC	PFC

325199	Adipic Acid Production	X

X

	331312	Aluminum Production	X

	X

325311	Ammonia Production	X

	327310	Cement Production	X

	334	Electronics Manufacturing	X

	X	X	X

325193	Ethanol Production	X

	331112	Ferroalloy Production	X	X

3116	Food Processing	X

	327	Glass Production	X

	325120	HCFC-22 Production	X

X

Hydrogen Production	X

	331111	Iron and Steel Production	X	X

3314	Lead Production	X

	327410	Lime Manufacturing	X

	3314	Magnesium Production	X

	X

325311	Nitric Acid Production	X

X

	3251	Petrochemical Production	X	X

324110	Petroleum Refineries	X	X

325312	Phosphoric Acid Production	X

	3221	Pulp and Paper Manufacturing	X

	327910	Silicon Carbide Production	X	X

325181	Soda Ash Manufacturing	X

	325188	Titanium Dioxide Production	X

	3314	Zinc Production	X

In addition, there are a large number of industrial establishments across all industrial sectors that emit less significant amounts of GHGs (primarily CO2) from stationary source fuel combustion.  Combustion emissions from these establishments were analyzed under the Unspecified Industrial Stationary Combustion source category.

3.4.1  Data Sources

There were several primary data sources used in preparation of the permit threshold analysis.  EPA consulted analyses prepared in support of the GHG MRR for the 23 industrial sectors for which combustion, process and fugitive emissions were significant.  These documents can be found in the docket numbered EPA-HQ-OAR-2008-0508.  The TSDs contain industry-specific analyses of process, fugitive, and combustion emissions for industries.  Supporting analyses used to prepare the TSDs are found in entries 0046.7 and 0046.8 of the GHG MRR docket.  These emissions estimate details were helpful in breaking down TSD emission estimates to compare facility-specific emissions against the additional threshold levels considered in the permit threshold analysis, including 100, 250, 5,000, and 50,000 tons per year.

Combustion emissions analyses for the Unspecified Industrial Stationary Combustion sectors used data from the 2002 Manufacturing Energy Combustion Survey (MECS) and the U.S. Census Bureau's 2002 Economic Census.  MECS is a survey of manufacturing and industrial energy uses and costs prepared by the EIA (EIA, 2007).  Data is collected by manufacturing establishment through mailed questionnaires.  The 2002 MECS data reflects responses accounting for approximately 98 percent of the manufacturing payroll, and reports separate energy use estimates for 48 NAICS industrial sector groups.  The MECS provided information on the amount of fuel burned in 2002 by sector on an employment basis.  The 2002 Economic Census data provided information on the number of establishments sorted by three-digit NAICS code and disaggregated into specific size categories based on employment (U.S. Census, 2004).

3.4.2  Potential to Emit

As mentioned earlier in this document, permit threshold analyses considered both actual emissions and PTE.  When capacity information was not available, the analyses applied utilization rates from the Industrial Production and Capacity Utilization, Federal Reserve Statistical Release G-17 in order to adjust actual emissions to determine PTE emissions.  These utilization rates are prepared quarterly with annual revisions, and are published on the web (  HYPERLINK "http://www.federalreserve.gov/releases/g17"  http://www.federalreserve.gov/releases/g17 ).  The main data source for the industrial production and capacity utilization rates is the U.S. Census Bureau's Census of Manufactures.  Data introduced from other Census Bureau publications include the Census of Services and the Services Annual Survey (for publishing) and selected Current Industrial Reports.  Additional government source data include new annual data on minerals from the U.S. Geological Survey (USGS) and updated deflators from the Bureau of Economic Analysis (BEA).  In addition, the annual revisions include monthly production estimates that reflect updated seasonal factors and the inclusion of monthly source data that became available (or were revised) after the closing of the regular four-month reporting window.

3.4.3  Methodology for New Units

	To determine the number of new units per year, EPA compared the number of establishments by three-digit NAICS code in 1998 to the number of establishments by three-digit NAICS code in 2002, and determined an average annual growth rate for each three-digit NAICS code.  The growth rates were applied to each threshold count to determine the number of annual new establishments per industry per threshold.  If the growth rate was determined to be negative, EPA assumed that no new establishments would be added; however, establishments were not reduced to reflect negative growth rates.  EPA also supplemented these growth rates with agency estimates of expected new sources from various information collection requests (ICR) and regulatory impact analyses (RIA) efforts.

3.5  Methodology for Existing Unspecified Industrial Stationary Combustion Source Category Emissions

	In order to determine establishment counts and emissions totals for the unspecified industrial stationary combustion sources, EPA used 2002 Economic Census data showing manufacturing employment by NAICS code and Manufacturing Energy Consumption Survey (MECS) data published by EIA.  Calculating greenhouse gas emissions required determining energy consumption per employee by industry and applying emission factors specific to the consumption profile derived from MECS data.

The Economic Census data (2002) provide a count of establishments by employment category, where employment category is defined by number of employees (e.g., 1 – 4,

5 – 9,…,500 – 999,…,more than 2,500).  The MECS energy consumption data provide energy consumption by industry.  Both the employment data and the energy consumption data are organized according to the NAICS codes.

As part of this analysis, EPA calculated industry-specific GHG emission factors.  The factors were calculated by considering actual fuel consumption in 2002, as determined by EIA.  Actual fuel consumed was multiplied by fuel-specific GHG emission factors to determine GHG emissions by fuel type by industry.  To simplify the analysis, EPA only included CO2 emissions and ignored CH4 and N2O in the CO2e calculations.  CO2 makes up between 99.3 and 99.7 percent of estimated CO2e emissions.  Emissions for each fuel type were combined to determine total emissions for a sector.  Total emissions per sector were divided by total energy consumption per sector to determine a factor to calculate GHG emissions per mmBtu of energy consumption specific to the industrial sector.

The GHG emission factors were then multiplied by the energy consumption per employee in order to determine emissions per employee.  Multiplying the result by the average number employees per establishment, EPA determined total GHG emissions per establishment.  The total emissions numbers were used to determine number of establishments and volume of emissions that would be caught by each of the permit thresholds under consideration.

As discussed previously, a separate threshold analysis was conducted for 23 industrial sectors determined to have significant GHG emissions in the GHG MRR analysis.  In order to quantify the unspecified industrial stationary combustion source emissions, the combustion emissions and establishment counts from 19 of these sectors were subtracted from the total industrial MECS analysis.  For the remaining four industries, HCFC-22 production, hydrogen production, magnesium production, and nitric acid production, EPA could not readily isolate combustion emissions.  For these industries, their establishment counts were subtracted from the unspecified industrial source threshold counts based on process emission threshold evaluations, assuming that any facility exceeding a threshold for process-based emissions would exceed the threshold regardless of their combustion CO2 emissions.

Potential to Emit

In order to determine potential to emit from the MECS and Economic Census numbers, EPA assumed a capacity utilization factor of 50%.  There is a wide variety of generally smaller manufacturing sources included under this general source category.  Based on comments we received on the proposed GHG tailoring rule, we are using a 50% capacity utilization rate for this final analysis to better reflect what can be deemed reasonable operation under normal conditions for facilities in these source categories.  Sources may operate their combustion equipment at levels above and below this capacity utilization rate, but we believe the 50% utilization rate reflects a reasonable average rate across the variety of facilities represented in this category.

New Units

EPA applied industry-specific growth rates to each sector and summed across sectors in order to determine number of new units.

Threshold Summary

Table 10

CO2e Threshold Summary -- Unspecified Industrial Stationary Combustion

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	172,142	546	372.307

250	112,659	319	367.636

1,000	64,535	239	357.855

5,000	20,785	83	318.759

10,000	12,215	61	289.198

25,000	5,875	18	245.579

50,000	3,272	12	206.881

100,000	958	2	145.106

3.6  Methodology for Existing Specific Industrial Sectors Considering Combustion, Process, and Fugitive Emissions

These analyses were based primarily on the GHG MRR TSDs and the supporting analyses, including facility specific emission information.  The estimates considered each greenhouse gas separately.  The GHG MRR TSDs included threshold counts and emissions calculations for 1,000, 10,000, 25,000, and 100,000 metric tons per year.  Two steps were required for permit threshold consideration.  First, emissions were recalculated in order to conduct the analysis in short tons for comparison to the permit thresholds.  Second, the emissions were considered against the finer threshold stratification considered in the permit threshold analysis.

For the permit threshold analysis, EPA determined that if the GHG MRR analysis showed all of the establishments exceeded a threshold, after adjustment for short tons, all of the establishments exceeded any lower thresholds.  However, where fewer than 100 percent of the establishments exceeded a threshold, additional analysis was required to compare emissions to the permit thresholds of 100, 250, 5,000, and 50,000 tons per year.  EPA used the supporting summaries for the GHG MRR which included facility-specific consumption, process, and fugitive emission reports in order to determine counts and emissions for each of the permit thresholds.

3.6.1  Adipic Acid Production

	There are four Adipic Acid Production plants in the U.S., all of which are estimated to exceed the highest 100,000 metric tons per year emission threshold for CO2e on an actual emissions basis.  Therefore all plants will also exceed all PTE thresholds on a CO2e basis.  The CO2e emission estimate includes N2O process emissions that total about 5.9 million metric tons CO2e, and 3.4 million metric tons of CO2 from stationary fuel combustion sources.

N2O

	Individual plant production and emission estimates were not made available because of confidential business information (CBI) claims.  However, from the Technical Support Document for the Adipic Acid Production Sector:  Proposed Rule for Mandatory Reporting of Greenhouse Gases (EPA-HQ-OAR-2008-0508-0005), overall U.S. adipic acid production was estimated to total approximately one million metric tons in 2006.  The smallest U.S. plant only produced about two percent of the total.  This plant, however, is the only plant that is uncontrolled.  The three larger plants with the bulk of production have control equipment with N2O control efficiencies that range from 90 to 99 percent.

	The uncontrolled N2O emission factor is 300 kg N2O/mton adipic acid.  Based on the two percent production share, this uncontrolled plant emitted about 6,000 metric tons of N2O (no GWP adjustment).  This leaves about 13,100 metric tons of N2O from the three larger controlled plants.  Two plants representing about 64 percent of production have control efficiencies in the range of 90 to 95 percent, and one plant with about 34 percent of production has control close to 99 percent (EPA, 2001).

	Assuming similar production shares today, the share of national production (which is assumed for this analysis to be equivalent to capacity) appears to range from 30 to 35 percent for the three plants.  Therefore, emissions and PTE for the controlled plants range from to 4,000 metric tons to 4,700 metric tons of N2O per year.

CO2

	The CO2 emissions from fuel combustion can similarly be apportioned to the four plants.  The smallest plant, with only two percent of national production, is estimated at CO2 emissions of 67,500 metric tons, and the next smallest, with 30 percent of national production, is estimated at 101,300 metric tons.

Potential to Emit

	The PTE for each facility was assumed to be equivalent to the emissions based on the apportionment described above.

New Units

EPA assumed that no new plants would be constructed for this sector.

Threshold Summary

Table 11

CO2 Threshold Summary -- Adipic Acid Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

100	4	0	3.376

250	4	0	3.376

1,000	4	0	3.376

5,000	4	0	3.376

10,000	4	0	3.376

25,000	4	0	3.376

50,000	4	0	3.376

100,000	3	0	3.309

Table 12

N2O Threshold Summary -- Adipic Acid Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	N2O Emissions Covered

(Tg per year)

100	4	0	0.019

250	4	0	0.019

1,000	4	0	0.019

5,000	1	0	0.006

10,000	0	0	0

25,000	0	0	0

50,000	0	0	0

100,000	0	0	0

Table 13

CO2e Threshold Summary -- Adipic Acid Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	4	0	9.298

250	4	0	9.298

1,000	4	0	9.298

5,000	4	0	9.298

10,000	4	0	9.298

25,000	4	0	9.298

50,000	4	0	9.298

100,000	4	0	9.298

3.6.2  Aluminum Production

	The primary aluminum production process results in emissions of CO2 and PFCs.  The reduction of the alumina occurs through electrolysis in a molten bath of natural or synthetic cryolite (Na3AlF6).  The reduction cells contain a carbon lining that serves as the cathode.  Carbon is also contained in the anode, which can be a carbon mass of paste, coke briquettes, or prebaked carbon blocks from petroleum coke.  During reduction, most of the carbon in the anode is oxidized and released to the atmosphere as CO2.

Potential to Emit

CO2

	The Technical Support Document for Process Emissions from Primary Production of Aluminum:  Proposed Rule for Mandatory Reporting of Greenhouse Gases (EPA-HQ-OAR-2008-0508-0006) apportioned CO2 emission estimates from the U.S. GHG inventory to the 13 operating smelters based on each smelters share of total capacity.  Operating smelter emissions were all above 100,000 tons of CO2, so no PTE estimate was required.  Capacity information for the two idle smelters shows that these smelters are also capable of emitting over 100,000 tons of CO2 per year.

PFCs

	The reduction cells also emit two PFCs:  perfluoromethane (CF4) and perfluoroethane (C2F6).  The GWPs of the two PFCs are 6,500 and 9,200 respectively.  During the smelting process, when the alumina ore content of the electrolytic bath falls below critical levels required for electrolysis, rapid voltage increases occur, which are termed "anode effects."  Anode effects cause carbon from the anode and fluorine from the dissociated molten cryolite bath to combine, and produce fugitive emissions of CF4 and C2F6.

	Anode effects released approximately 2.5 million metric tons of CF4 and C2F6 in 2006 as documented in the GHG MRR TSD.  CF4 made up at least 85 percent of the combined emissions in 2006 (Inventory of U.S. GHG Emissions and Sinks:  1990 – 2007).  These emissions on a CO2e basis are equivalent to about 410 short tons of combined emissions as PFC.  The proposed GHG MRR TSD estimated CO2e emissions from primary aluminum smelters at full capacity.  The largest smelter has 11 percent of U.S. operating capacity.  Therefore the largest smelter has a PTE of not more than 45 tons of PFC, and no facilities have a PTE greater than 100 tons.

New Units

	No new primary aluminum facilities are expected to be built.  The growth rate in primary metals from the Economic Census data is only about 0.4 percent.

Threshold Summary

	Threshold summaries are displayed below for CO2 and CO2e.  All facilities have a PFC PTE less than 100 tons per year on a PFC basis.

Table 14

CO2 Threshold Summary -- Primary Aluminum

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	GHG Emissions Covered

(Tg per year)

100	15	0	3.800

250	15	0	3.800

1,000	15	0	3.800

5,000	15	0	3.800

10,000	15	0	3.800

25,000	15	0	3.800

50,000	15	0	3.800

100,000	15	0	3.800

Table 15

CO2e Threshold Summary -- Primary Aluminum

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	GHG Emissions Covered

(Tg per year)

100	15	0	3.951

250	15	0	3.951

1,000	15	0	3.951

5,000	15	0	3.951

10,000	15	0	3.951

25,000	15	0	3.951

50,000	15	0	3.951

100,000	15	0	3.951

3.6.3  Ammonia Production

	EPA reviewed the proposed Supporting Data for Threshold Analysis Subpart E – W, Greenhouse Gas Mandatory Reporting Rulemaking, March 10, 2009 (EPA-HQ-OAR-2008-0508-0046.7) to determine actual emissions and calculate the potential to emit for 24 ammonia plants in operation.  The analysis spreadsheet details CO2 actual emission calculations for each plant based on ammonia production and urea production, and CO2, CH4, and N2O emission calculations for stationary fuel combustion based on 2006 data.  For purposes of permit threshold analysis, the CH4 and N2O emissions from combustion were not significant.

Potential to Emit

Capacity information in the spreadsheet is based on the engineering design capacity adjusted for 340 days per year of effective production capability, using information provided by the United States Geological Survey (USGS).  The PTE estimates were made by multiplying the actual emission estimates by the ratio of annual ammonia capacity to annual ammonia production adjusted to 365 days a year of operation instead of 340.  EPA assumed that ratio also held for stationary combustion units at the plant.

New Units

EPA assumed that no new plants would be constructed for this sector.

Threshold Summary

Table 16

CO2e Threshold Summary -- Ammonia Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	24	0	14.543

250	24	0	14.543

1,000	24	0	14.543

5,000	24	0	14.543

10,000	24	0	14.543

25,000	24	0	14.543

50,000	24	0	14.543

100,000	22	0	14.540

3.6.4  Cement Production

Process-related CO2 emissions from cement production are the second largest source of industrial CO2 emissions in the United States.  Cement production is done in two stages.  The first stage is clinker production.  In clinker production, raw materials (primarily limestone) are heated to induce calcination and produce lime.  Lime reacts with silica-containing materials and iron ore and aluminum to form clinker.  During the process, CO2 is generated as a byproduct and released to the atmosphere.  Also during clinker production, some of the clinker raw materials form partially or fully calcinated cement kiln dust instead of forming clinker, resulting in additional process-related CO2 emissions.  In the second stage of the production process, the clinker is ground and mixed with gypsum and other materials to make cement.

Potential to Emit

The Technical Support Document for Process Emissions from Cement:  Proposed Rule for Mandatory Reporting of Greenhouse Gases (EPA-HQ-OAR-2008-0508-0008) shows 107 cement facilities in the U.S., 106 of which exceed all permit thresholds for CO2 (according to the TSD, the one facility that does not exceed the 100,000 tons per year threshold accounted for over 90,000 metric tons of CO2e and approximately one-tenth of one percent of the cement industry emissions in 2006).

New Units

Growth for the industrial sector was estimated at 0.4 percent, and as such, no additional facilities were included in this analysis.

Threshold Summary

Table 17

CO2e Threshold Summary -- Cement Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	107	0	86.83

250	107	0	86.83

1,000	107	0	86.83

5,000	107	0	86.83

10,000	107	0	86.83

25,000	107	0	86.83

50,000	107	0	86.83

100,000	106	0	86.74

3.6.5  Electronic Production

	The Technical Support Document for Process Emissions from Electronics Manufacture (Semiconductors, MEMs, Liquid Crystal Displays, and Photovoltaics) (EPA-HQ-OAR-2008-0508-0009) examined emissions of high GWP gases for semiconductor and related industry plants.  Emissions from stationary fuel combustion were not included in the source category analysis, but were instead captured by the unspecified industrial stationary combustion analysis.  EPA has followed this approach here as well.

	Approximately one million metric tons of SF6 as CO2e were emitted from the semiconductor industry in 2006 (Inventory of U.S. Greenhouse Gas Emissions and Sinks:  1990 – 2007).  This is equivalent to 46 short tons of SF6.  The semiconductor industry uses multiple long-lived fluorinated gases in plasma etching and plasma enhanced chemical vapor deposition (PECVD) processes to produce semiconductor products.  These include PFCs, which are also used as heat transfer fluids.  Approximately 3.5 million metric tons of PFCs as CO2e were emitted from the semiconductor industry in 2006 (Inventory of U.S. Greenhouse Gas Emissions and Sinks:  1990 – 2007).

Table 18

Electronic Production PFC Emissions

Semiconductor PFC	2006 CO2e Emissions

(million mtons)	PFC GWP	2006 PFC Emissions

(tons)

CF4	1.2	6,500	204

C2F6	2.2	9,200	264

C4F8	0.1	8,700	13

Total	3.5	--	481

Potential to Emit

The Federal Reserve capacity utilization factor for the electronics industry in 2006 was 79.8 percent.  Based on this capacity utilization factor the PTE of all of the semiconductor plants combined is estimated at 56 tons of SF6 and 600 tons of PFC.

	EPA identified 216 facilities in the semiconductor-electronics sector.  Of these, the largest facility emitted six percent of total semiconductor emissions on a CO2e basis (includes non-PFCs), which is a maximum of 30 tons of PFC.  On a PTE basis, the largest facility would emit 36 tons, based on an assumption that the industry capacity is distributed similarly to emissions.  Therefore no facility exceeds 100 tons per year on an actual or PTE basis for PFC.

New Units

Growth for the industrial sector was estimated at -1.8 percent, and as such, no additional facilities were included in this analysis.

Threshold Summary

	Electronics industry emissions from plant processes only exceed emission thresholds on a CO2e basis.  Facility stationary fuel combustion emissions are not included in the threshold comparisons for the industry.

Table 19

CO2e Threshold Summary -- Electronics Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	199	0	5.948

250	191	0	5.947

1,000	159	0	5.934

5,000	109	0	5.819

10,000	88	0	5.701

25,000	65	0	5.399

50,000	54	0	5.100

100,000	22	0	3.417

3.6.6  Ethanol Production

	In the proposed GHG MRR, EPA determined that the sources of GHG emissions at ethanol production facilities that must be reported under the proposed rule are stationary fuel combustion, onsite landfills, and onsite wastewater treatment.  For the GHG MRR supporting analysis, data were unavailable to estimate facility emissions from these combined sources.  Instead, data on stationary fuel combustion requirements for different plant capacities were used to estimate the minimum number of facilities that would meet each of the examined reporting rule facility-level thresholds.  CO2 emissions from combustion constitute the majority of the GHG emissions from ethanol production and therefore provide an adequate measure for determining threshold counts.

Table 20

Ethanol Fuel Combustion CO2e Emissions by Plant Size

(from the Proposed GHG MRR TSD Spreadsheet)

Ethanol Produced

(wet milling process) (million gallons)	Coal Combustion Emissions

(mtons CO2e/year)	Natural Gas Combustion Emissions

(mtons CO2e/year)

290	1,519,585	853,536

245	1,283,787	721,091

200	1,047,990	588,646

200	1,047,990	588,646

100	523,995	294,323

85	445,396	250,174

40	209,598	117,729

35	183,398	103,013

20	104,799	58,865

2.6	13,624	7,652

Table 21

Proposed Reporting Rule Threshold Analysis Results

Threshold CO2e

(tons per year)	Number of Existing

Sources -- Actual Basis	Percent of Existing

National Sources*

1,000	101	72%

10,000	93	66%

25,000	86	61%

100,000	43	31%

*  National ethanol production source population was estimated at 140 plants nationwide.

Potential to Emit

The permit threshold PTE analysis relied on this same approach and data.  Therefore CH4 emissions from onsite landfills and wastewater treatment plant digesters were not included in the PTE analysis, and we did not estimate emission coverage at each threshold.  Also, the analysis for the proposed GHG MRR did not evaluate thresholds of 100, 250, 5,000, and 50,000 tons per year.  EPA assumed that all existing plants would exceed the 100 and 250 ton per year thresholds based on fuel combustion associated with the wet milling process.  For the 5,000 and 50,000 thresholds, EPA included the number of sources exceeding the next highest threshold.  For example, the count of sources exceeding the 5,000 tons per year level only includes the sources exceeding the 10,000 ton threshold in the Technical Support Document for Ethanol Facilities:  Proposed Rule for Mandatory Reporting of Greenhouse Gases (EPA-HQ-OAR-2008-0508-0010).

New Units

	EPA estimates that ten new ethanol production facilities will be built per year.

Threshold Summary

Table 22

CO2e Threshold Summary -- Ethanol

GHG Threshold (tons per year)	Number of

Existing Sources	Number of New Sources Added

per Year

100	140	10

250	140	10

1,000	101	7

5,000	101	7

10,000	93	7

25,000	86	6

50,000	86	6

100,000	43	3

3.6.7  Ferroalloy Production

	In evaluating ferroalloy production in the U.S., EPA considered actual production at six facilities, as published in the U.S. Inventory of Greenhouse Gas Emissions and Sinks:  1990 – 2007 for 2006, and the capacity to produce at three facilities for which production information was not published due to competitive concerns.

Potential to Emit

	EPA's PTE calculations consider the Federal Reserve's 2006 monthly industrial capacity utilization estimates for the primary metals industry classification which shows utilization at 85.9 percent for 2006.  The PTE calculations do not affect the threshold analysis, because all facilities emit over 100,000 metric tons of CO2e per year.

New Units

Applying the growth factor for the industrial sector, 0.4 percent, results in no additional facilities for the analysis.

Threshold Summary

Table 23

CO2 Threshold Summary -- Ferroalloy Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

100	9	0	1.717

250	9	0	1.717

1,000	9	0	1.717

5,000	9	0	1.717

10,000	9	0	1.717

25,000	9	0	1.717

50,000	9	0	1.717

100,000	9	0	1.717

Table 24

CH4 Threshold Summary -- Ferroalloy Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CH4 Emissions Covered

(Tg per year)

100	3	0	0.0003

250	0	0	0

Table 25

CO2e Threshold Summary -- Ferroalloy Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	9	0	1.726

250	9	0	1.726

1,000	9	0	1.726

5,000	9	0	1.726

10,000	9	0	1.726

25,000	9	0	1.726

50,000	9	0	1.726

100,000	9	0	1.726

3.6.8  Food Processing

Food processing includes meat, poultry and fruit and vegetable processing.  Emissions derive from combustion and fugitive methane related to wastewater treatment.  For purposes of this permit threshold analysis, EPA did not consider the fugitive methane from wastewater treatment because these are the only greenhouse gas emissions from the source category other than combustion, and food processing is not a listed PSD source category.  Consequently, emissions from this subsector considered in this analysis were limited to combustion emissions and were calculated using the MECS approach.

Potential to Emit

EPA used the Federal Reserve's 2004 capacity utilization factor of 79.3 percent for the food industry to calculate PTE emissions.

New Units

In addition, new establishments were calculated assuming a continuation of the growth rate of 1.2 percent, as calculated using the methodology described earlier in this document.

Threshold Summary

Table 26

CO2 Threshold Summary -- Food Processing

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	3946	47	16.848

250	2281	27	16.709

1,000	1499	18	16.379

5,000	1030	12	15.723

10,000	749	9	14.354

25,000	482	6	12.257

50,000	10	0	0.596

100,000	0	0	0

3.6.9  Glass Manufacturing

	EPA used the Supporting Data for Threshold Analysis Subpart E – W, Greenhouse Gas Mandatory Reporting Rulemaking, March 10, 2009 (EPA-HQ-OAR-2008-0508-0046.7), to analyze emissions for permit thresholds from glass manufacturing.  Annual fuel combustion and glass production are estimated for each plant based on 2004 estimated plant sales and 2002 MECS energy intensity (energy per sales dollars).  The spreadsheet shows CO2 emission estimates from industrial processes and stationary fuel combustion, as well as CH4 and N2O emission estimates from stationary fuel combustion.

Potential to Emit

Plant capacities are not available in the spreadsheet.  To estimate PTE, EPA divided the actual annual emissions by a capacity utilization factor of 0.50 or 50 percent.

New Units

EPA used an estimated annual growth rate of 0.4 percent for the nonmetallic mineral product manufacturing sector to determine the number of new units for this analysis.

Threshold Summary

Table 27

CO2e Threshold Summary -- Glass Manufacturing

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	369	1	4.425

250	364	1	4.425

1,000	222	1	4.341

5,000	201	1	4.302

10,000	175	1	4.162

25,000	104	0	3.277

50,000	21	0	1.208

100,000	3	0	0.366

3.6.10  HCFC-22 Production

	Chlorodifluoromethane (HCFC-22) is produced for use in refrigeration and air conditioning systems and as a chemical feedstock for manufacturing synthetic polymers.  Because HCFC-22 depletes stratospheric ozone, its production for non-feedstock uses is scheduled to be phased out by 2020 under the U.S. Clean Air Act.  Feedstock production, however, is permitted to continue indefinitely.

	A high global warming potential (GWP) greenhouse gas, trifluoromethane (HFC-23), is generated as a byproduct during the manufacture of HCFC-22.  Emissions of HFC-23 in 2006 were estimated to be 13.8 million metric tons on a CO2e basis from three HCFC-22 production plants.  Estimates were based on the plants operating at capacity.  Annual emissions in terms of both metric tons CO2e and tons HFC-23 are summarized in Table 30 below.

Table 28

HCFC-22 Production HFC-23 Emissions

HCFC-22 Production	2006 CO2e Emissions

(million metric tons)	HFC GWP	2006 HFC Emissions

(short tons)

HFC-23	13.8	11,700	1,300

Source:  Reporting Rule TSD

Potential to Emit

Confidential business information (CBI) claims on production information limited EPA's PTE analysis.  The Technical Support Document for Emissions of HFC-23 from Production of HCFC-22:  Proposed Rule for Mandatory Reporting of Greenhouse Gases (EPA-HQ-OAR-2008-0508-0015) estimated that all three plants emit over 100,000 metric tons CO2e on a capacity basis by a factor of 85 or more, or a minimum of 800 short tons of HFC-23.  These estimates did not account for HFC-23 capture and destruction at two of the three plants.  Therefore, actual emissions at two of the plants will be lower, and can be limited through permitting.  We assumed that all three plants exceed the 100 and 250 ton actual and PTE thresholds, and that one plant (uncontrolled) exceeds the 1,000 ton PTE threshold.

	Because the TSD did not include estimates of CO2 emissions from fuel combustion, and the CBI claims noted above, the PTE analysis does not quantify fuel combustion emissions specifically for the three plants.  Stationary fuel combustion emissions from the plants were instead captured under the analysis for unspecified industrial stationary combustion.

New Units

	U.S. production between 1990 and 2006 increased by 11 percent while emissions declined by 62 percent.  The declines in emissions from control equipment and process changes offset the production increases.  Therefore we did not estimate any new facilities or modifications that would increase facility emissions more than 100 tons per year.

Threshold Summary

Table 29

HFC Threshold Summary -- HCFC-22 Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	HFC Emissions Covered

(Tg per year)

100	3	0	0.001

250	3	0	0.001

1,000	1	0	0.001

5,000	0	0	0

Table 30

CO2e Threshold Summary -- HCFC-22 Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	3	0	13.848

250	3	0	13.848

1,000	3	0	13.848

5,000	3	0	13.848

10,000	3	0	13.848

25,000	3	0	13.848

50,000	3	0	13.848

100,000	3	0	13.848

3.6.11  Hydrogen Production

EPA estimated CO2 emissions from merchant hydrogen production using the process and combustion ratio of 8.62 tons of CO2 emissions per ton of hydrogen production.  About 95 percent of all hydrogen (not just merchant hydrogen) produced in the U.S. today is made from natural gas via steam methane reforming.  In steam methane reforming fueled by natural gas combustion, the process and combustion emissions go up the same stack from the boiler/reformer unit.  Because the emissions are predominately process emissions and because the natural gas combustion products are emitted from the same stack, EPA has treated all the emissions as process emissions.

Potential to Emit

	EPA developed estimates assuming hydrogen production at capacity level.  Therefore, no adjustment to the emissions estimates is needed to account for PTE emissions.

New Units

Based on the industry growth factor of -0.1 percent for chemical manufacturing, EPA assumed that no new plants would be constructed.

Threshold Summary

Table 31

CO2 Threshold Summary -- Hydrogen Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	75	0	15.227

250	75	0	15.227

1,000	74	0	15.226

5,000	62	0	15.202

10,000	51	0	15.130

25,000	42	0	15.007

50,000	38	0	14.890

100,000	32	0	14.441

3.6.12  Iron and Steel Production

	EPA used the Supporting Data for Threshold Analysis Subpart E – W, Greenhouse Gas Mandatory Reporting Rulemaking, March 10, 2009 (EPA-HQ-OAR-2008-0508-0046.7) for the proposed GHG MRR threshold analysis to determine process and combustion CO2 and process CH4.  The iron and steel production source category includes taconite iron ore processing facilities, integrated iron and steel making facilities, electric arc furnace (EAF) steelmaking facilities that are not located at integrated iron and steel facilities, and coke oven facilities that are not located at integrated iron and steel facilities.  Facility processes and facilities covered in the spreadsheet are shown in the table below.

Table 32

Iron and Steel Processes, Facilities, and Capacity Information

Iron and Steel Process	Number of Facilities	Capacity Information

Basic oxygen furnace (BOF)	18	Yes

Blast Furnace (BF)	17	Yes

Sintering	5	Yes

Coke ovens	18	Yes

Electric arc furnace (EAF)	92	No

Taconite furnace	8	Yes

Integrated steel plant fuel combustion*	19	No

Coke oven gas combustion*	9	No

EAF steel plant fuel combustion	92	No

* Six plants had emissions from coke oven gas combustion was included in integrated steel plant fuel combustion.

Potential to Emit

The analysis covered 130 plants, and in all cases, except for EAF plants, GHG emissions were estimated based on operations at plant capacity.  For EAF plants, EPA used the 2007 Federal Reserve industrial capacity utilization percentage of 86.6 percent for primary metal -- iron and steel production, to adjust estimated actual emissions to PTE.

	The spreadsheet contained emission CO2e estimates which included CO2, CH4, and N2O emissions.  Process CH4 emissions were backed out of the CO2e totals using the process CH4 emissions reported in the U.S. GHG Inventory, and apportioning these emissions to the different plants based on their capacity in those processes.  N2O emissions are primarily related to fuel combustion and were not backed out for separate treatment.

New Units

No new iron and steel facilities are expected to be built.  The growth rate in primary metals from the Economic Census data is only about 0.4 percent.

Threshold Summary

Table 33

CO2 Threshold Summary -- Iron and Steel Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per year	CO2 Emissions Covered

(Tg per year)

100	130	0	85.150

250	130	0	85.150

1,000	130	0	85.150

5,000	129	0	85.148

10,000	128	0	85.141

25,000	123	0	85.057

50,000	116	0	84.831

100,000	113	0	84.655

Table 34

CH4 Threshold Summary -- Iron and Steel Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CH4 Emissions Covered

(Tg per year)

100	18	0	0.034

250	17	0	0.033

1,000	17	0	0.033

5,000	3	0	0.011

10,000	0	0	0

Table 35

CO2e Threshold Summary -- Iron and Steel Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	130	0	85.151

250	130	0	85.151

1,000	130	0	85.151

5,000	130	0	85.151

10,000	128	0	85.141

25,000	123	0	85.058

50,000	116	0	84.832

100,000	114	0	84.656

3.6.13  Lead Production

According to the 2006 U.S. Geological Survey (USGS), lead production in the U.S. includes both the primary, direct smelting (one facility) and secondary lead production (16 facilities).  Process emissions of CO2 are a byproduct of the coke consumed during the smelting or reforming processes.  EPA calculated total process emissions based on lead production as reported in the USGS.

In the Supporting Data for Threshold Analysis Subpart E – W, Greenhouse Gas Mandatory Reporting Rulemaking (EPA-HQ-OAR-2008-0508-0046.7), combustion emissions are combined with process emissions to determine total actual emissions.

Potential to Emit

In order to determine PTE emissions, EPA considered the Federal Reserve's 2006 monthly industrial capacity utilization estimates for primary metals industry classification which shows utilization at 85.9 percent for 2006, and adjusted to achieve 100 percent utilization.

New Units

EPA assumed no new facilities would be added for the industry, given an expected growth rate of 0.4 percent per year for primary metal manufacturing industry.

Threshold Summary

Table 36

CO2e Threshold Summary -- Lead Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	17	0	0.861

250	17	0	0.861

1,000	17	0	0.861

5,000	17	0	0.861

10,000	16	0	0.855

25,000	13	0	0.799

50,000	12	0	0.761

100,000	1	0	0.089

3.6.14  Lime

	The Supporting Data for Threshold Analysis Subpart E – W, Greenhouse Gas Mandatory Reporting Rulemaking, March 10, 2009 (EPA-HQ-OAR-2008-0508-0046.7) was also used to estimate GHG PTE for lime plants.

Potential to Emit

To estimate PTE, EPA divided annual actual CO2 emissions from the calcining process and fuel combustion emissions of CO2, CH4, and N2O by regional capacity factors available in the spreadsheet for each plant.  The capacity factors ranged from 43 to 136 percent.

New Units

EPA assumed no new facilities would be added for the industry.

Threshold Summary

Table 37

CO2 Threshold Summary -- Lime Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

100	89	0	27.262

250	89	0	27.262

1,000	89	0	27.262

5,000	89	0	27.262

10,000	89	0	27.262

25,000	86	0	27.237

50,000	66	0	26.533

100,000	60	0	26.180

3.6.15  Magnesium Production and Processing

	The magnesium metal production (primary and secondary) and casting industry typically uses SF6 as a cover gas to prevent the rapid oxidation and burning of molten magnesium in the presence of air.  A dilute gaseous mixture of SF6 with dry air and/or CO2 is blown over molten magnesium metal to induce and stabilize the formation of a protective crust.  A small portion of the SF6 reacts with the magnesium to form a thin molecular film of mostly magnesium oxide and magnesium fluoride.  The amount of SF6 reacting in magnesium production and processing is being studied but presently assumed to be negligible, and therefore all SF6 used is assumed to be emitted into the atmosphere.

	For the proposed GHG MRR Technical Support Document for Process Emissions from Magnesium Production and Processing:  Proposed Rule for Mandatory Reporting of Greenhouse Gases, EPA reported that national annual SF6 emissions from magnesium production and processing totaled approximately 3.2 million metric tons CO2e in 2006.  The facility population totaled 13 facilities that emitted 3.0 million metric tons CO2e.  The SF6 emissions (no GWP adjustment) were 148 and 138 short tons respectively.  Ten magnesium die casting facilities accounted for 29 percent (44 tons), and primary and secondary production accounted for 64 percent (96 tons) of the total emissions.  Other small casting activities accounted for the remaining 7 percent (ten tons).

Potential to Emit

EPA used the analysis in the TSD for the proposed GHG MRR, where EPA had evaluated thresholds of 1,000, 10,000, 25,000, and 100,000 metric tons per year.  Facility-level information is not made publicly available because of confidential business information (CBI) claims.  From that earlier analysis EPA estimated that the same number of facilities exceeded the 100, 250, and 1,000 tons CO2e per year PTE threshold as determined in the GHG MRR TSD for the 1,000 metric tons per year threshold.  In a similar fashion, EPA used the GHG MRR TSD facility counts at 10,000 metric tons CO2e per year to estimate facilities at the 5,000 tons per year PTE threshold, and 100,000 metric tons per year for the 50,000 tons CO2e per year PTE threshold.  The permit threshold analysis did not include CO2 emissions from fuel combustion.  That information was not available in the TSD for the proposed GHG MRR.

On an SF6 mass basis, the average emissions per facility are only 11 tons of SF6, well below 100 tons per year.  Therefore we assumed that none of the facilities have a potential to emit more than 100 tons per year of SF6.

New Units

EPA assumed no new units would be added for the sector.

Threshold Summary

Table 38

CO2e Threshold Summary -- Magnesium Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	13	0	2.955

250	13	0	2.955

1,000	13	0	2.955

5,000	11	0	2.94

10,000	11	0	2.94

25,000	11	0	2.94

50,000	9	0	2.781

100,000	9	0	2.781

3.6.16  Nitric Acid Production

	EPA used the 2006 nameplate capacity (metric tons of HNO3 100 percent acid basis) for 45 nitric acid plants and 2006 acid production from the GHG MRR TSD supporting spreadsheet (EPA-HQ-OAR-2008-0508-0046.7) to determine N2O emissions.

Potential to Emit

The GHG PTE was calculated by multiplying actual N2O emissions as CO2e by the ratio of nameplate capacity to 2006 production.  The permit threshold analysis, based on the GHG MRR TSD, does not include GHG emissions from co-located stationary combustion units.  Also the permit threshold analysis does not account for overlap between facilities in the Nitric Acid and Ammonia categories, which have both ammonia and nitric acid production processes.

New Units

EPA assumed no new units would be constructed for this sector.

Threshold Summary

Table 39

N2O Threshold Summary -- Nitric Acid Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	N2O Emissions Covered

(Tg per year)

100	43	0	0.055

250	42	0	0.055

1,000	27	0	0.049

5,000	4	0	0.016

10,000	0	0	0

25,000	0	0	0

50,000	0	0	0

100,000	0	0	0

Table 40

CO2e Threshold Summary -- Nitric Acid Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	45	0	17.732

250	45	0	17.732

1,000	45	0	17.732

5,000	45	0	17.732

10,000	45	0	17.732

25,000	44	0	17.724

50,000	43	0	17.706

100,000	42	0	17.667

3.6.17  Petrochemical Production

EPA determined that the portion of the petrochemical production sector most relevant for permit threshold analysis includes the manufacture and production of acrylonitrile, carbon black, ethylene, ethylene dichloride, ethylene oxide, and methanol, because the IPCC considers production of greenhouse gases from these processes significant compared to other petrochemical processes.

Emissions from the manufacturing processes vary significantly and process emissions take many forms.  Process emissions include direct oxidation of CO2, off-gassing of CH4 and CO2, and the direct release of CO2 and CH4 from equipment leaks.  Process emissions are the primary consideration for acrylonitrile, ethylene, and ethylene oxide processes.  In addition, some processes require combustion of supplemental fuel.  Both process and combustion emissions are significant for carbon black and methanol processes.

Potential to Emit

EPA's analysis assumed petrochemical production at the capacity level.  Therefore, no adjustment to the emissions estimates is needed to account for PTE.

New Units

Based on an industry growth factor of -0.1 percent for chemical manufacturing, EPA assumed that no new plants would be constructed.

Threshold Summary

Table 41

CO2 Threshold Summary -- Petrochemical Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

100	98	0	52.081

250	98	0	52.081

1,000	98	0	52.081

5,000	97	0	52.080

10,000	96	0	52.073

25,000	96	0	52.073

50,000	94	0	52.005

100,000	91	0	51.806

Table 42

CH4 Threshold Summary -- Petrochemical Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CH4 Emissions Covered

(Tg per year)

100	55	0	0.130

250	52	0	0.129

1,000	37	0	0.121

5,000	5	0	0.035

10,000	1	0	0.010

25,000	0	0	0

50,000	0	0	0

100,000	0	0	0

Table 43

CO2e Threshold Summary -- Petrochemical Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	98	0	54.826

250	98	0	54.826

1,000	98	0	54.826

5,000	97	0	54.825

10,000	96	0	54.818

25,000	96	0	54.818

50,000	94	0	54.748

100,000	91	0	54.595

3.6.18  Petroleum Refineries

In developing the permit threshold analysis for petroleum refineries, EPA quantified CH4 process emissions from wastewater, fugitive, flares, and storage tanks.  Process CO2 emissions derived from flares, hydrogen plant emissions, and sulfur plant emissions.  In addition, on-site combustion emissions were calculated considering fuel consumed by type.

Potential to Emit

EPA assumed that petroleum refineries were operating at capacity level.  Therefore, no adjustment to the emissions estimates was needed to account for PTE.

New Units

According to the ICR prepared for the New Source Performance Standard (NSPS), EPA expects that no new refineries will be built over the next few years.

Threshold Summary

Table 44

CO2 Threshold Summary -- Petroleum Refineries

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

100	150	0	202.947

250	150	0	202.947

1,000	150	0	202.947

5,000	150	0	202.947

10,000	149	0	202.938

25,000	146	0	202.887

50,000	137	0	202.575

100,000	129	0	202.065

Table 45

CH4 Threshold Summary -- Petroleum Refineries

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CH4 Emissions Covered

(Tg per year)

100	129	0	0.083

250	109	0	0.080

1,000	31	0	0.042

5,000	0	0	0

Table 46

CO2e Threshold Summary -- Petroleum Refineries

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	150	0	204.897

250	150	0	204.897

1,000	150	0	204.897

5,000	150	0	204.897

10,000	149	0	204.888

25,000	146	0	204.835

50,000	137	0	204.513

100,000	129	0	203.988

3.6.19  Phosphoric Acid Production

Phosphoric acid is produced by combining sulfuric acid and phosphate rock.  CO2 is emitted when the limestone component of phosphate rock reacts with the sulfuric acid.

Potential to Emit

When these process emissions are combined with combustion emissions, all 14 plants have emissions that exceed the highest threshold level; consequently, no PTE analysis was required.

New Units

Based on an industry growth factor of -0.1 percent for chemical manufacturing, EPA assumed that no new plants would be constructed.

Threshold Summary

Table 47

CO2 Threshold Summary -- Phosphoric Acid Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	14	0	3.838

250	14	0	3.838

1,000	14	0	3.838

5,000	14	0	3.838

10,000	14	0	3.838

25,000	14	0	3.838

50,000	14	0	3.838

100,000	14	0	3.838

3.6.20  Pulp and Paper Manufacturing

Permit threshold analysis for this sector is focused on the energy intensive, fugitive emitting pulp, paper, and paperboard manufacturing subsectors.  Process emissions include CO2 which is emitted in the recovery cycle at kraft and soda facilities associated with the chemical pulp process.  The CO2 emitted from kraft mill lime kilns originates from two sources:  (1) fossil

fuels burned in the kiln; and (2) conversion of calcium carbonate (or "lime mud") generated in the recovery process to calcium oxide.

The bulk of the emissions considered derive from combustion.  Many boilers use biomass fuel, and the burning of spent pulping liquors to produce steam for facility processes is considered biomass combustion for the GHG MRR.  The emissions numbers considered for the permit threshold analysis are non-biogenic (net of any biogenic emissions).  Considering only non-biogenic emissions, 96.5 percent of the facilities and 99.7 percent of the emissions are captured by all of the thresholds proposed for consideration of the permit threshold rule.

Potential to Emit

Because 99.7 percent of emissions were captured at even the highest threshold, no additional PTE estimate was calculated in this analysis.

New Units

Based on an industry growth factor of -2.5 percent for paper manufacturing, and previous EPA analysis for the pulp and paper NSPS ICR, EPA assumed that no new plants would be constructed.

Threshold Summary

Table 48

CO2e Threshold Summary -- Pulp and Paper Manufacturing

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	425	0	57.700

250	425	0	57.700

1,000	425	0	57.700

5,000	425	0	57.700

10,000	425	0	57.700

25,000	425	0	57.700

50,000	422	0	57.688

100,000	410	0	57.527

3.6.21  Silicon Carbide Manufacturing

In 2006, one facility produced silicon carbide in the U.S.  Silicon carbide is primarily an industrial abrasive manufactured from silica sand or quartz and petroleum coke.  Approximately 35 percent of the carbon from the petroleum coke is retained with the silicon carbide, and the rest is emitted as both CO2 and CH4.  In addition, emissions from combustion account for approximately ten percent of total emissions.

Potential to Emit

Emissions from this plant exceed all permit threshold levels; as a result, EPA did not consider PTE calculations.

New Units

EPA assumed there would be no new facilities constructed.

Threshold Summary

Table 49

CO2 Threshold Summary -- Silicon Carbide Manufacturing

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

100	1	0	0.101

250	1	0	0.101

1,000	1	0	0.101

5,000	1	0	0.101

10,000	1	0	0.101

25,000	1	0	0.101

50,000	1	0	0.101

100,000	1	0	0.101

Table 50

CH4 Threshold Summary -- Silicon Carbide Manufacturing

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CH4 Emissions Covered

(Tg per year)

100	1	0	0.0004

250	1	0	0.0004

1,000	0	0	0

Table 51

CO2e Threshold Summary -- Silicon Carbide Manufacturing

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	1	0	0.109

250	1	0	0.109

1,000	1	0	0.109

5,000	1	0	0.109

10,000	1	0	0.109

25,000	1	0	0.109

50,000	1	0	0.109

100,000	1	0	0.109

3.6.22  Soda Ash Production

Soda Ash production emissions were nearly evenly split between process and combustion emissions.  Process emissions result from calcining trona ore to produce soda ash.

Potential to Emit

PTE emissions were calculated based on the capacities of the production units.

New Units

In 2006, there was a glut of soda ash in the domestic market; EPA assumed no new units would be constructed.

Threshold Summary

Table 52

CO2e Threshold Summary -- Soda Ash Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	5	0	3.121

250	5	0	3.121

1,000	5	0	3.121

5,000	5	0	3.121

10,000	5	0	3.121

25,000	5	0	3.121

50,000	5	0	3.121

100,000	5	0	3.121

3.6.23  Titanium Dioxide Production

EPA used USGS as the source for production capacity for the eight facilities that produced titanium dioxide in 2006.

Potential to Emit

Emissions were assumed to represent PTE operating levels.

New Units

EPA assumed that no new plants would be constructed.

Threshold Summary

Table 53

CO2e Threshold Summary -- Titanium Dioxide Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	8	0	3.686

250	8	0	3.686

1,000	8	0	3.686

5,000	8	0	3.686

10,000	8	0	3.686

25,000	8	0	3.686

50,000	8	0	3.686

100,000	7	0	3.628

3.6.24  Zinc Production

	The Zinc production emissions and facility count estimates include process and combustion emissions associated with primary smelting and secondary recycling facilities.

Potential to Emit

For PTE estimates, EPA considered the Federal Reserve's 2006 monthly industrial capacity utilization estimates for primary metals industry classification which shows utilization at 85.9 percent for 2006, and adjusted to achieve 100 percent utilization.

New Units

EPA assumed that no new units would be constructed.

Threshold Summary

Table 54

CO2e Threshold Summary -- Zinc Production

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	9	0	0.852

250	9	0	0.852

1,000	9	0	0.852

5,000	9	0	0.852

10,000	8	0	0.843

25,000	5	0	0.802

50,000	5	0	0.802

100,000	5	0	0.802

3.7  Energy Sector

3.7.1  Oil and Gas Systems

	In consideration of the permit thresholds, EPA considered the Fugitive Emissions Reporting from the Petroleum and Natural Gas Industry:  Background Technical Support Document (EPA-HQ-OAR-2008-0508-0023).  This document details combustion emissions and fugitive emissions from offshore petroleum and natural gas facilities, onshore natural gas processors, onshore natural gas transmission, underground natural gas storage, and liquid natural gas storage.  EPA determined that oil and gas exploration, development, transmission, and distribution are not listed PSD source categories, and therefore fugitive emissions from these activities were not considered for PSD applicability as it relates to major source thresholds.  EPA's analysis focused on combustion emissions from these sources.

Potential to Emit

EPA used a capacity utilization figure of 50 percent to determine PTE emission estimates and counts.  This rate is meant to reasonably represent an average utilization rate across a variety of combustion equipment types used in the oil and gas industry subsectors described above.

New Units

EPA determined new units based on a growth factor of 1.0 percent for the sector.

Threshold Summary

Table 55

CO2e Threshold Summary -- Oil and Gas Systems

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	4762	48	88.264

250	4762	48	88.264

1,000	4762	48	88.264

5,000	3722	37	86.192

10,000	3095	31	83.619

25,000	2496	25	79.386

50,000	1045	10	56.949

100,000	387	4	32.750

3.7.2  Underground Coal Mining

	GHG emissions from underground coal mining include CH4 fugitive emissions released from the coal seam and surrounding rock during mining and post-mining activities (coal bed CH4), and fuel combustion emissions of CO2, CH4, and N2O.  Fugitive CH4, emissions are captured and vented by ventilation systems and degassing systems.  Captured and vented CH4 emissions from active mines were considered in the PTE analysis.  Because underground coal mining is not one of the 28 PSD source categories for which fugitive emissions were required to be included in the emissions determination, fugitive emissions from post mining operations, surface mines, and inactive mines were not included in the permit thresholds analysis.

	The Technical Support Document for Underground Coal Mines:  Proposed Rule for Mandatory Reporting of Greenhouse Gases (EPA-HQ-OAR-2008-0508-0032) identified 612 active underground coal mining facilities but analysis of CH4 emissions was limited to 128 "gassy" mines where CH4 monitoring was already in place (due to existing CH4 emissions above Mine Safety and Health Administration (MSHA) threshold levels).  The U.S. GHG Inventory (EPA, 2008) reports that 233 underground coal mines (including 133 gassy mines) ventilated CH4 in 2007.  Fuel combustion emission estimates for the GHG MRR TSD from all underground coal mines, based on U.S. Census energy use data, were found to comprise between one and three percent of total CO2e emissions, with coal bed CH4 accounting for the bulk of GHG emissions.

	In addition to the emissions data on the 128 gassy mines contained in the GHG MRR TSD, EPA considered combustion emissions from 289 bituminous underground coal mines, using U.S. Census data from 2002.

Potential to Emit

CH4

	CH4 emission estimates that were developed for the GHG MRR TSD were used for both actual emissions and PTE emissions permit threshold analysis.  EPA assumed that venting and degassing were continuous throughout the year; therefore, actual emission estimates equal PTE emission estimates.  The estimates considered 128 gassy mines, which were assumed to be the largest emitters of vented CH4.  The smallest mine of this group had annual CH4 emissions of 26 tons; therefore EPA assumed that the annual CH4 emissions from the 105 vented mines that were not included in the TSD analysis were less than 26 tons.

CO2

	CO2 emissions were estimated in the same manner as for other Unspecified Industrial Stationary Combustion categories, based on the ICF analysis (ICF, 2007) using the MECS approach.  Emissions were estimated based on Census information including fuel consumption per employee and the distribution of establishments by the number of employees.  PTE was estimated by using a capacity utilization factor of 86.3 percent as published by the Federal Reserve.

New Units

	The number of underground bituminous coal mines in the U.S. is on the decline.  EIA data show that only Colorado had an increase in the number of underground coal mines between 2006 and 2007 (EIA, 2008).  The EIA data show that overall the number of underground coal mines decreased from 2006 to 2007 by eight percent; consequently, EPA assumed no new underground mines would be built.    HYPERLINK "http://www.eia.doe.gov/cneaf/coal/page/acr/table1.html"  http://www.eia.doe.gov/cneaf/coal/page/acr/table1.html .

Threshold Summaries

	Threshold summary tables are shown below for CH4 (vented fugitive emissions), CO2 (fuel combustion), and CO2e (vented fugitive CH4 and combustion CO2).

Table 56

CO2 Threshold Summary -- Underground Coal Mining

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	238	0	0.783

250	202	0	0.778

1,000	63	0	0.692

5,000	30	0	0.577

10,000	30	0	0.577

25,000	0	0	0

Table 57

CH4 Threshold Summary -- Underground Coal Mining

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	110	0	1.586

250	110	0	1.586

1,000	110	0	1.586

5,000	53	0	1.420

10,000	38	0	1.361

25,000	24	0	1.147

50,000	13	0	0.784

100,000	1	0	0.105

Table 58

CO2e Threshold Summary -- Underground Coal Mining

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2e Emissions Covered

(Tg per year)

100	238	0	39.520

250	238	0	39.520

1,000	126	0	33.945

5,000	124	0	33.943

10,000	123	0	33.936

25,000	103	0	33.606

50,000	78	0	32.800

100,000	55	0	31.241

3.8  Waste Sector

3.8.1  Landfills

	The landfill PTE analysis includes both municipal solid waste (MSW) landfills and onsite industrial landfills associated with pulp and paper and food processing.  The analysis used a modification of the landfill emission modeling approach described in the Technical Support Document for the Landfill Sector:  Proposed Rule for Mandatory Reporting of Greenhouse Gases (EPA-HQ-OAR-2008-0508-0034), which was used for the proposed GHG MRR threshold analysis.  Like the GHG MRR analysis, the permit threshold PTE analysis did not include onsite industrial landfills for ethanol processing facilities or industrial land application systems.

GHG Emissions

	Decomposition of waste in landfills generates CH4 and CO2.  The amount of CH4 generated from a given landfill is a function of several factors:  the total amount of waste disposed in the landfill; the characteristics of the waste; and the climatic conditions.  The amount of CH4 emitted is the amount of CH4 generated minus the amount of CH4 oxidized by aerobic microorganisms in the landfill cover material.  Also subtracted from the total is the amount of CH4 that is destroyed by combustion of the vented gas.  The CO2 produced by decaying waste is not considered an anthropogenic emission, and is not counted in GHG emission totals.  Likewise, CO2 resulting from the combustion of landfill CH4 is not accounted for as an anthropogenic emission under international accounting guidance.

	According to the 2008 U.S. Inventory, MSW landfills emitted 111.2 million metric tons CH4 (CO2e basis) in 2006.  The majority of the CH4 emissions from on-site industrial landfills occurs at pulp and paper facilities and food processing facilities.  In 2006, these landfills emitted 14.6 million metric tons CO2e

Potential to Emit

	The methodology used for the proposed GHG MRR threshold analysis was also used to estimate CH4 generation rates and emissions in 2006 for the PTE analysis.  A landfill-specific model developed by EPA to support its proposed GHG MRR was used to estimate CH4 generation and potential generation from municipal landfills.  The generation estimate was adjusted with assumptions on oxidation in landfill cover, and destruction by combustion for energy recovery or flaring.  The industrial landfill generation and emission estimates are based on the U.S. GHG Inventory.  Industrial landfills were assumed not to have energy recovery or flaring, so there was no difference between generation and emissions.

New Units

	EPA did not estimate the number of new facilities added each year with CH4 emissions above the different thresholds due to the time delay between landfill construction and emission generation.

Threshold Summary

Table 59

CO2e Threshold Summary -- Landfills

GHG Threshold

(tons per year)	Number of Existing Sources	CO2e Emissions Covered

(Tg per year)

100	4,131	125.621

250	4,117	125.619

1,000	4,053	125.592

5,000	3,564	124.552

10,000	3,265	122.788

25,000	2,701	115.937

50,000	1,684	92.340

100,000	967	72.722

Table 60

CH4 Threshold Summary -- Landfills

GHG Threshold

(tons per year)	Number of Existing Sources	CH4 Emissions Covered

(Tg per year)

100	3,885	5.973

250	3,562	5.931

1,000	2,692	5.539

5,000	981	3.274

10,000	427	2.326

25,000	114	1.087

50,000	21	0.401

100,000	2	0.106

3.8.2  Municipal Solid Waste Combustors

	The threshold analysis for the proposed GHG MRR included municipal solid waste combustors (MWC) in the general stationary fuel combustion category.  The analysis used the eGRID database, which is discussed in the PTE methodology description for electric generating units.

Data and Methodology

	EPA used the latest version of the eGRID database (2006) to estimate the PTE of MWC facilities and counts of facilities above the different emission thresholds.  The eGRID database includes year 2004 characteristics, operating information, and annual CO2 emissions for U.S. facilities that have a generation capacity greater than one MW and sell electric power to the grid.  By using eGRID, EPA assumed that all MWC facilities sell power to the grid.

Potential to Emit

	EPA identified 75 MWC facilities based on the generator primary fuel in the generator table (primary fuel equals MSW) in the eGRID database.  The eGRID database contains CO2 annual emissions estimates for the facilities.  For CO2 emissions, eGRID uses a standard assumption that 70 percent of the heat value of the waste stream comes from renewable materials and 30 percent comes from nonrenewable materials.  The renewable fraction has a CO2 emission rate of zero; therefore, the PTE threshold analysis is based on the nonrenewable or fossil fraction assumption.  EPA estimated PTE by dividing the annual emissions from eGRID by the eGRID plant capacity factor.

New Units

	To determine the number of new per year at different thresholds, EPA counted the number of generators online each year, and totaled the nameplate capacity for each online year.  This information was compared to the total facility nameplate capacity, and the PTE for the increased capacity was calculated by multiplying the facility PTE by the fraction of nameplate capacity associated with the new generators.  EPA counted the facilities that exceeded the PTE thresholds during each period, and computed a 15-year average to determine the number of new or modified facilities per year.

Threshold Summary

Table 61

CO2 Threshold Summary -- Municipal Solid Waste Combustors -

GHG Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

100	75	2	6.255

250	75	2	6.255

1,000	75	2	6.255

5,000	75	2	6.255

10,000	75	2	6.255

25,000	74	2	6.24

50,000	67	1	6.071

100,000	40	1	4.958

3.9  Agriculture (Stationary Fuel Combustion)

	The analysis for the Agriculture sector was limited to stationary fuel combustion CO2 emissions from internal combustion diesel engine generators.  Fugitive emissions of CH4 from enteric fermentation, and CO2, CH4, and N2O from manure management were not included because farms and related operations are not in the 28 PSD source categories that require quantification of fugitive emission PTE for determining major source status, and because of the large uncertainties and lack of information on determining what component of the non-combustion emissions at agricultural operations would be defined as non-fugitive for PSD purposes.  Fuel combustion for building space heating and other farm purposes were not included in the estimates, but would be a component of farm PTE.

Data and Methodology

	EPA used the 2007 ICF analysis to estimate the number of farms covered by the different thresholds (ICF, 2007).  Emissions from diesel generators on farms were estimated using data on the average generator size in Delaware (EEA, 2004), and data on energy use on farms for non-transport/non-machinery motors (Brown and Neal 2005).  Using these data, EPA estimated the number of diesel generators on farms and apportioned the generators across farm sizes, assuming no farm has more than one generator.

Potential to Emit

	EPA assumed that a high proportion of farms would run the generators infrequently, and a smaller proportion would have a generator as the only power source, requiring nearly constant operation.  EPA used this distribution to determine actual and potential emissions, with PTE emissions based on the assumption that the generators ran 24 hours per day, 365 days per year.

	EPA recognizes that this approach underestimates the PTE for all farm stationary fuel combustion sources, because it is limited to diesel engine generators used primarily to run pumps and motors, and does not include additional sources such as fuel combustion for drying and curing, space heating, and water heating.

New Units

	New generator installations were estimated based on information in the Regulatory Impact Analysis (RIA) for the spark ignition stationary combustion engine NSPS and area NESHAPS (EPA, 2007).  The on-farm engine population of diesel generators used for irrigation increased four percent between 1998 and 2003, or about 0.8 percent annually.

Threshold Summary

Table 62

CO2 Threshold Summary -- Farm Stationary IC Engines

CO2 Threshold

(tons per year)	Number of Existing Sources	Number of New Engines Added

per Year	CO2 Emissions Covered

(Tg per year)

100	37,351	299	0.512

250	37,351	299	0.512

1,000	0	0	0

5,000	0	0	0

10,000	0	0	0

25,000	0	0	0

50,000	0	0	0

100,000	0	0	0

3.10  Commercial Stationary Fuel Combustion

Data Source

	EPA used EIA's Commercial Building Energy Consumption Survey (CBECS) to estimate commercial sector stationary fuel combustion GHG emissions and PTE.  CBECS is a national sample survey that collects information on the stock of U.S. commercial buildings, their energy-related building characteristics, and their energy consumption and expenditures.  Commercial buildings include all buildings in which at least half of the floor space is used for a purpose that is not residential, industrial, or agricultural; thus, the source category includes building types that might not traditionally be considered "commercial," such as schools, correctional institutions, and buildings used for religious worship.  The CBECS survey is conducted every four years and the most recent survey was completed for 2003.

	The CBECS survey sample was designed so that survey responses could be used to estimate characteristics of the entire nationwide commercial building stock.  The 2003 survey selected 6,955 potential case buildings for sampling.  The sampling procedures resulted in 5,215 completed building interviews for a response rate of 82 percent.  To make national estimates from the sample data, EIA calculated base sampling weights for each building (the reciprocal of the probability of that building being selected into the sample).  In other words, the base sampling weight is the number of national buildings represented by the sampled building.  The base weight was further adjusted to account for nonresponsive bias.

	EIA publishes summary tables from the survey, and posts "microdata" files on the EIA website.  The CBECS microdata consist of the 5,215 sampled building records, which each correspond to a single sampled building.  For each building, these files contain information such as the building size, climatic region, census region, year constructed, types of energy used, and energy consumption and expenditures.  These individual building microdata records are also the basis for the summary tables published by EIA.

Emissions Methodology

	EPA used the CBECS microdata to estimate commercial building emissions and populations above emission thresholds.  Each of the 5,215 microdata records corresponds to a single sampled building.  EIA has made available 20 different data files of the microdata records which contain a wide range of information on characteristics and energy use for each building.

	EPA's analysis relied on guidance provided by EIA on how to use the data.  As noted above, the CBECS sample was designed so that survey responses could be used to estimate characteristics of the entire commercial building stock nationwide.  The table below provides examples from EIA on how to calculate national commercial building characteristics from the sample building data.

Table 63

EIA Website Examples

To Find the National Estimate for:	Do This...	And You

Should Get...

Total number of buildings	Sum ADJWT8 (weight factor)	4,858,749.82

(or 4,859 thousand)

Total number of office buildings	Sum ADJWT8 for cases where PBA8 (building code) = "02"	823,805.47

(or 824 thousand)

Total floor space	Create a new variable (weighted square footage) by multiplying ADJWT8 by SQFT8 (floor space) for each case, then sum this new variable	71,657,900,522

(or 71,658 million ft2)

Total floor space in buildings with air conditioning	Sum the new weighted square footage variable (see above) for cases where COOL8 (air conditioning) = "1"	63,559,999,624

(or 63,560 million ft2)

Total electricity consumption in KWh 	Create a new variable (weighted electricity consumption) by multiplying ADJWT8 by ELCNS8 (electricity consumption) for each case, then sum this new variable	1,043,175,710,751

(or 1,043 billion kWh)

Source:    HYPERLINK "http://www.eia.doe.gov/emeu/cbecs/cbecs2003/public_use_2003/cbecs_pudat a2003.html"  http://www.eia.doe.gov/emeu/cbecs/cbecs2003/public_use_2003/cbecs_pudata 2003.html .

	EIA calculated base sampling weights for each surveyed building (these are the reciprocal of the probability of that building being selected into the sample).  Therefore, a building with a base weight of 1,000 represents itself and 999 similar but unsampled buildings in the total building stock.  The base weight is further adjusted to account for non-response bias.  The variable "ADJWT8" in the data file is the final weight.  The ADJWT8 weight factor is used as described in Table 63 to extrapolate the survey sample to a national scale for any value.  In order to obtain a national value each sample building's value must be multiplied by the building's weight (ADJWT8).  All of the weighted values are then summed.

2003 CO2 Emissions

	EPA calculated the CO2 emissions for each of the 5,215 buildings based on the annual natural gas and oil consumption reported for the building.  For national emission estimates and counts of buildings with annual CO2 emissions over any threshold, EPA multiplied the base weights by the sample emission totals to determine the national estimate of buildings with emissions over the threshold.

Potential to Emit

	EPA estimates that commercial buildings operate at 15 percent of capacity.  EPA considered several sources in making the PTE factor determination:

●	A report prepared by Energy and Environmental Analysis, Inc. for Oak Ridge National Laboratory describing the industrial and commercial boiler population in the United States (EEA, 2005).  The report estimated an average commercial boiler capacity factor of 16 percentമ

●	Reports on cooking equipment energy use by the Food Service Technology Center in California suggesting that the cooking equipment in food service establishments operate at about ten percent of a theoretical maximum capacity based on 8,760 hours per year (Pechan, et.al, 2008).

●	A study of Los Angeles dry cleaners performed by the Pollution Prevention Education and Research Center (PPERC) in 2004 which demonstrates that dry cleaners operate boilers at about 10 to 15 percent of maximum capacity over a normal year (Pechan, et al., 2008).

New Buildings

	The CBECS data identifies the year the sampled buildings were constructed.  We used the construction year information to identify the number of new buildings built each year in the 1990 to 2003 period.  Counts of the average number of these buildings built per year were then made at the different emissions and PTE thresholds.

Threshold Summary

	The count of buildings and emissions at the threshold levels for the entire sector are shown in the table below.  Threshold results by commercial building categories (e.g., offices, public assembly, schools) are provided in Appendix B.

Table 64

CO2 Threshold Summary -- Commercial Sector Stationary Fuel Combustion

CO2 Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

100	1,355,921	22,123	119.262

250	731,477	12,041	105.306

1,000	172,654	2,922	69.885

5,000	18,167	196	29.384

10,000	5,660	96	17.765

25,000	1,161	7	8.790

50,000	600	3	6.003

100,000	51	2	1.012

3.11  Residential Buildings

Data Sources

	EPA used residential fuel consumption data from EIA's Residential Energy Consumption Survey, and multi-family building and unit data from U.S. Census (Census) surveys to estimate CO2 emissions and PTE for fuel combustion at single and multi-family residential properties.  The RECS is a national area-probability sample survey that collects energy-related data for occupied primary housing units.  The most recent 2005 survey collected data from 4,382 households in housing units statistically selected to represent the 111.1 million housing units in the United States.  RECS data are tabulated for the four Census regions, the nine Census divisions, and for the four most populous States -- California, Florida, New York, and Texas.

	The RECS sample was designed so that survey responses could be used to estimate characteristics of the national stock of occupied housing units.  In order to arrive at national estimates from the RECS sample, EPA calculated base sampling weights for each housing unit as the reciprocal of the probability of that building being selected into the sample.  Therefore, a housing unit with a base weight of 10,000 represents itself and 9,999 similar, but not sampled housing units in the total stock of occupied residential housing units.  The base weight is further adjusted to account for non-response bias.  Ratio adjustments were also used to ensure that the RECS weights add up to Census Current Population Survey estimates of the number of households.

	The RECS data are provided at the housing unit level, and not at the building level.  EPA used additional data from the Census on multi-family building population characteristics to estimate total property emissions and PTE for multi-unit properties.  Census data were from two sources:  the Property Owner and Manager Survey (POMS, 1996) and the American Housing Survey (AHS, 2005).

3.11.1  Single-Family Homes

	The RECS data was used directly to estimate CO2 emissions from fossil fuel combustion at single-family housing units for space heating, water heating, and appliances.  EPA assumed that each unit in an attached single-family building was a separate source, with combustion equipment under different ownership.

	The annual energy consumption by fuel (1,000 Btus) for the surveyed unit was multiplied by the fuel CO2 emission factor to estimate annual emissions.  Total single-family unit emissions for the entire country were calculated by multiplying CO2 emissions for each units by the base sampling weight.

Potential to Emit

	The PTE for a single-family unit was calculated by dividing the CO2 emissions from the unit by a capacity factor of 0.1.  This factor was estimated by comparing the average annual CO2 emissions per heated floor space area per hour by climate zone, to required heat input capacity.  The required heat input capacity was based on rule of thumb heating system requirements for the different climate zones.  The table below shows the average Btu/ft2-hour from the RECS data and Heating Requirement (Btu/ft2) by climate zone.  A heating system efficiency of 80 percent was used to estimate the required space heating capacity.

Table 65

Single-Family Detached and Attached

Households with Fossil Fuel-Fired Space Heating

(from RECS, 2005)

Households (millions)	Climate Zone(s)	Heating Degree

Day Range	Average Annual Fuel Consumption (Btu/ft2-hour)	Space Heating Requirement* (Btu/ft2)

6.8	5	> 7,000	4.8	50 – 60

16.7	4	5,500 – 7,000	5.4	45 – 50

17.0	3	4,000 – 5,499	4.6	40 – 45

18.9	1 and 2	< 4,000	3.8	Zone 2:  35 – 40

Zone 1:  30 – 35

*  Heating requirement ranges are from   HYPERLINK "http://www.acdirect.com/systemsize.php"  www.acdirect.com/systemsize.php .

3.11.2  Multi-Family Residential Buildings

Emission Rates

	As noted earlier in the Data Source section, the RECS data are on an individual unit basis, not building or property basis, so a different approach was required for multi-family units where EPA assumed common ownership of the property fuel combustion equipment.  In order to estimate property emissions and the number of properties above different emission and PTE thresholds, EPA combined the RECS data with data from the POMS and AHS.

	From the RECS data, EPA first calculated average residential unit CO2 emissions for the two most common fuels (natural gas and oil) by multi-family category.  These are shown in the table below.

Table 66

Multi-Family Residential Unit -- Average Annual CO2 Emissions

(from RECS, 2005)

Multi-Family Category

(number of units)	Natural Gas Space Heating

(tons CO2/residential unit-year)	Fuel Oil Space Heating

(tons CO2/residential unit-year)

2 to 4 units	4.8	8.3

5 or more units	3.0	8.9

	EPA also obtained annual CO2 emission rates from an EPA analysis that was based on Lawrence Berkeley National Lab (LBNL) modeling studies.  Those rates were estimated for old and new building units (see Table 67).  The pre-1980 building estimate compares with the overall average from the RECS data.  The post-1980 building estimates are much lower, particularly for units burning fuel oil.

Table 67

Multi-Family Residential Unit -- Average Annual CO2 Emissions

(from 2008 EPA Analysis based on LBNL, 1997)

Multi-Family Category

(building age)	Gas Serviced Units

(tons CO2/residential unit-year)	Fuel Oil Serviced Units

(tons CO2/residential unit-year)

Pre-1980 building	4.75	7.17

Post-1980 building 	2.65	3.87

Existing Property Characteristics

	Information on the distribution of multi-family properties by number of units per property was taken from the 1995 – 1996 POMS.  The data are aggregated by different housing unit ranges.  The table below shows the property size distribution from unpublished POMS data (NMHC Quick Facts -- Apartment Stocks (  HYPERLINK "http://www.nmhc.org"  http://www.nmhc.org )).  The POMS data were for privately owned housing only and excluded public housing projects (about 13,500 buildings and 1,326,000 units).  For our estimates, the building numbers were adjusted to current (2005) levels based on the RECS unit data (unit ratio of RECS to POMS).  EPA assumed the same unit distribution in the adjustment.

Table 68

Multi-Family Residential Property Size Distribution

(from National Multi-Housing Council tabulation of unpublished POMS data 1995 – 1996)

Number of Rental Units on Property	Number of Properties

(1995 – 1996)	Number of Units

(1995 – 1996)	Average Number of Units per Property

2	1,558,700	3,093,200	2

3	336,030	1,025,900	3

4	341,350	1,436,800	4

5 – 9	281,500	1,897,700	7

10 – 14	70,390	862,280	12

15 – 19	36,780	602,260	16

20 – 29	38,000	916,750	24

30 – 39	18,166	604,240	33

40 – 49	14,431	702,790	49

50 – 99	26,694	2,009,400	75

100 – 199	19,804	2,952,300	149

200 – 299	7,775	1,948,400	251

300 – 399	2,966	1,058,800	357

400 – 499	1,307	605,130	463

500 – 749	723	431,360	597

Over 750	307	437,670	1,426

Total	2,754,923	20,584,980

	The adjusted POMS size distribution and average number of units in each category were combined with information from RECS on the percentage of units that use gas or oil for space heating.  The gas and oil emission factors from the previous tables were applied to the average number of units in each property size category by fuel to estimate property annual CO2 emissions.

	For our final estimates we used the LBNL based emission factors for post-1980 buildings, over the RECS based factor.  We found that these lower emission factors resulted in total emissions more in line with the total based on all RECS units and residential sector estimates in the U.S. Greenhouse Gas Inventory.  The RECS-based factors combined with the POMS property distribution data resulted in a larger overestimate in overall category annual emissions.  The lack of information on the building population over 50 units, and lack of information on the correlation between unit emissions and the building/property size are large sources of uncertainty in the estimates at thresholds above 1,000 tons.

Potential to Emit

	PTE was estimated using the same ten percent capacity factor as used for the single family residential units

New Properties

	The AHS data provided information on new construction used to estimate the number of new buildings and new units with natural gas space heating that were constructed in the 1999 – 2005 period.  To simplify the analysis, EPA ignored the limited use of fuel oil for space heating in new units.

	The AHS data provided separately the number of new buildings with gas space heating per year, and a size distribution for all new buildings per year.  The AHS size distribution stopped at 50 and larger, and was slightly different in other categories from the POMS data.  EPA adjusted the distribution based on the POMS distribution and then used the same emission and capacity factor approach as used for existing units.

Table 69

American Housing Survey New Building Data

Building Size:  Number of Units per Building	Number of New Buildings per Year

(1999 – 2005) (thousands)	Fraction of All New Buildings per Year

(1999 – 2005)	New Gas Buildings

per Year

(1999 – 2005)

(thousands)	Number of New Gas Buildings per Year

2	6.3	0.22	16.0	3,468

3 – 4	5.4	0.19

2,995

5 – 9	6.1	0.21

3,389

10 – 19	6.0	0.21

3,310

20 – 29	3.1	0.11

1,734

30 – 49	1.0	0.03

552

50 or more	1.0	0.03

552

Total	29.0	1.00	16.0	16,000

Threshold Summary

Table 70

CO2 Threshold Summaries -- Residential Sectors

Threshold

(tons per year)	Number of Existing Sources	Number of New Facilities Added

per Year	CO2 Emissions Covered

(Tg per year)

Multi-Family Residential

100	610,500	11,300	54.285

250	137,000	6,400	42.192

1,000	51,200	1,100	32.399

5,000	7,800	120	14.934

10,000	1,400	20	4.933

25,000	160	3	1.392

50,000	20	0	0.006

100,000	0	0	0

Single-Family Residential

100	3,925,000	33,000	51.408

250	45,350	515	1.670

1,000	0	0	0

Total Residential Sector

100	4,535,500	44,300	105.693

250	182,350	6,915	43.862

1,000	51,200	1,100	32.399

5,000	7,800	120	14.934

100,00	1,400	20	4.933

25,000	160	3	1.392

50,000	20	0	0.006

100,000	0	0	0

References

Brown, E., and Elliott, R.N., On-Farm Energy Use Characterizations, Report Number IE052,

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