## Trends in Emissions of Fluorinated GHGs Reported under the Greenhouse Gas Reporting Program: Patterns and Potential Causes

Deborah Ottinger (Corresponding Author) a

, Mollie Averyt b , Deborah Harris c

, and Sally Rand d

a Climate Change Division, Office of Atmospheric Programs (6207J), Environmental Protection Agency, 1200 Pennsylvania Avenue NW., Washington, D.C. 20460, USA; telephone number: (202) 343

- 9149; fax number: (202) 343

- 2338 ; email address: ottinger.deborah@epa.gov

b ICF International, 1725 I Street N.W., Suite 1000, Washington D.C., 20006, USA; telephone number : (202) 862

- 15 69; fax number : (202) 862

- 1144 ; email address : Mollie.Averyt@icfi.com

c ICF International, 1725 I Street N.W., Suite 1000, Washington D.C., 20006, USA; telephone number : (202) 862

- 1574 ; fax number : (202) 862

- 1144 ; email address: Deborah.Harris@icfi.com

d Climate Change Division, Office of Atmospheric Programs (6207J), Environmental Protection Agency, 1200 Pennsylvania Avenue NW., Washington, DC 20460; telephone number: (202) 343

- 9739; f ax number: (202) 343

- 2338 ; email address: rand.sally@epa.gov2 Trends in Emissions of Fluorinated GHGs Reported under the Greenhouse Gas Reporting Program: Patterns and Potential Causes Deborah Ottinger (Corresponding Author) a

, Mollie Averyt b , Deborah Harris b , and Sally Rand a

a Climate Change Division, Office of Atmospheric Programs (6207J), Environmental Protection Agency b ICF International

Abstract: Since 2012, industrial users of fluorinated GHGs have been reporting their emissions of these GHGs under the U.S. EPA’s Greenhouse Gas Reporting Program (GHGRP). This paper discuss es the trends observed in these emissions over three years of reporting (for emissions that occurred from 2011 through 2013) , including patterns and potential explanations. Some industries, for example, manufacturers and users of electrical transmission and distribution equipment, have experienced significant reductions in report ed emissions since the beginning of the program. Analysis indicates that these reductions are concentrated among relatively large emitters. Possible explanations for these reductions include increased awareness by facilities of the magnitude of their emiss ions (both in absolute terms and relative to the emissions of similar facilities) and/or concerns regarding public perception of those emissions. The paper also compare s the emission reductions observed over the life of the GHGRP to those observed over th e lives of various voluntary emission reduction Partnerships to which many GHGRP reporters have belonged for more than a decade, examining whether the different conditions under which data are reported and publicized under the two programs have had an impa ct on emission reduction patterns.
Keywords: fluorinated greenhouse gas, emissions, trends, patterns, reductions

1. Introduction Fluorinated greenhouse gases (F

- GHGs) are greenhouse gases (GHGs) that contain fluorine. F

- GHGs include (1) perfluorocarbons (P FCs ); (2) hydrofluorocarbons (HFCs ); (3) sulfur hexafluoride (SF 6 ); (4) nitrogen trifluoride ( NF 3 ); and (5) other F

- GHGs that are used for applications such as heat transfer. 1 F

- GHGs, while emitted in lower quantities tha n other more common non
- carbon dioxide ( CO 2 ) GHGs (e.g., methane), have high global warming potentials ( GWPs ) and long atmospheric lifetimes (IPCC, 2007)

. T he observed atmospheric concentrations of these GHGs have increas ed rapidly in recent decades (see Figure 1 for examples ).

1 Investigating trends in GHG emissions requires converting emission quantities to a common carbon dioxide equivalent basis, which requires chemical

- specific global warming potentials (GWPs). Many of the “other F

- GHGs” do not have known GWPs. GWPs continue to be evaluated and are periodically evaluated and published by the International Panel on Climate Change (IPCC) and the U.S. Environmental Protection Agency.3 Figure 1. Atmospheric Concentration Trends of SF 6 (used in electric power systems, magnesium production, and electronics manufacturing) and NF 3 (mainly used in electronics manufacturing). **Source s**  **:** ( IPCC, 2007 ), ( Arnold et. al. 2012 ), Advanced Global Atmospheric Gases Experiment (AGAGE) data http://agage.eas.gatech.edu/data.htm

, and United States Geologic Survey data http: //water.usgs.gov/lab/software/air_curve/

F

- GHGs may be emitted from their use in industrial applications, as byproducts of production processes, or from their use as substitutes for ozone

- depleting substances. This paper focuses on the first two sou rces of emissions.
The U.S. Environmental Protection Agency (EPA) addresses emissions of F

- GHGs through a combination of both volu ntary and regulatory activities. A number of industrial emitters of F

- GHGs have partnered with EPA since the 1990s to volunta rily report and reduce F

- GHG emissions from their operations. EPA works closely with participating industries, tracking industry

- wide emission trends, benchmarking facility emission factors, 2 providing technical information

, and helping participants (Partners) overcome barriers to making process improvements that reduce emissions. Voluntary approaches have significantly reduced F

- GHG emission s from several industries , and it is expected that emissions of PFCs and SF 6 , in particular, will continue to d ecline as a result of voluntary action ( U

. S

. State Department 2014). As discussed further below, reports from Partners have provided key information on long

- term trends in emissions and emission factors from participating industries.

In 2011 and 2012
, large i ndustrial users and emitters of F

- GHGs began report ing emissions, among other data, to EPA under the Greenhouse Gas Reporting Program (GHGRP) (74 FR 56260). 3 Th is national program was established by regulation to

2 Emission factor or emission rate refers to the emissions per unit of activity, such as the kilo grams of PFCs emitted per tonne of aluminum produced. 3 Aluminum and HCFC

- 22 production facilities began reporting emissions in 2011, submitting estimates of their 2010 emissions in that year. Facilities producing electronics, fluorinated gases, magnesium , and electrical equipment, and users of electrical equipment, began reporting emissions in 2012, submitting 5 5.5

6 6.5

7 7.5

8

2000 2002 2004 2006 2008 2010 2012Concentratoins [ppt] SF6 Concentrations [AGAGE]
SF6 Concentrations (USGS)

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

2000 2002 2004 2006 2008 2010 2012Concentratoins [ppt]

NF3 Concentrations [Arnold et. Al]4 collect accurate , facility

- level G HG data to inform policy decisions and the public

. The GHGRP requires annual reporting by facilities that meet or exceed thresholds that are equivalent to emissions of 25,000 metric tons of CO 2 e per year.
The facilities required to report emissions of F

- GHGs fall into seven source categories

. These source categories , as well as the F

- GHGs emitted and emitting activity

, are provided in Table 1

.

Table 1 . Summary of EPA Categories of F

- GHG Emitters Subject to the GHGRP

Source a F

- GHGs Emitted Emitting Activity Aluminum Production (Subpart F) PFCs E mitted as a by

- product of process disturbances ( anode effects ) Electronics Manufacturing (Subpart I) HFCs, PFCs, SF 6 , NF 3 , others Etchant and chamber and wafer cleaning gas Magnesium Production and Processing (Subpart T) HFCs, SF 6 C over gas in magnesium production and casting to prevent metal oxidation Use of Electric Transmiss ion and Distribution (ET&D) Equipment (Subpart DD) b SF 6 I nsulator/arc quenching medium in the transmission and distribution of electricity

Manufacture of Electric Transmission and Distribution Equipment (Subpart SS) b SF 6 I nsulator/arc quenching medium in the transmission and distribution of electricity

Production of HCFC

- 22 and Destruction of HFC

- 23 (Subpart O) HFC

- 23 Emitted as by

- product of HCFC

- 22 production

Production of Fluorinated Gases (Subpart L) HFCs, PFCs, SF 6 , NF 3 , others Emitted as reactants, products, or by

products of production of fluorinated gases other than HCFC

- 22

a 40 CFR Part 98 designates subparts to categories of GHG emitters and suppliers. b GHGRP data indicates that a minimal amount of PFCs are used for manufacture of ET& D equipment. PFCs may be used in ET&D equipment, but emissions data reported under Subpart DD does not indicate that PFCs are being used in the United States.

F or most of the source categories in Table 1 ( with the exception of the Manufacture of Electric Transmission and Distribution Equipment )

, a significant share of reporters have ample experience in estimating, reporting, and reducing F

- GHG emissions through EPA’s High Global Warming Potential (High

- GWP) Gases Voluntary Programs

, including the:

• Voluntary Aluminum Industrial Partnership ( 1995

- ongoing ) ; 4

• HFC

- 23 Emission Reduction Agreement (1995

- 2010);

• SF 6 Emission Reduction Partnership for the Magnesium Industry ( 199 9

- 2010 ) ; 5

• PFC Reduction/Climate Partnership for the Semiconductor Industry ( 199 4

- 2010 ) ; and 6

estimates of their 2011 emissions in that year. A total of 41 source categories emitting CO2, methane, nitrous oxide, and fluorinated GHGs report u nder this regulation. 4 http://www.epa.gov/aluminum

- pfc/basic.html 5 http://www.epa.gov/highgwp/magnesium

- sf6/basic.html5 • S F 6 Emissions Reduction Partnership for Electric Power Systems ( 199 9

- ongoing)

. 7

When considered together, both voluntary and mandatory report s regarding F

- GHG emissions provide insights into emitting activities and mitigation efforts in the United States at the national and industry level

. This paper presents the trends observed in GHGRP reported F

- GHG emissions
, and investigates and discusses potential reasons for the observed patterns, including the trends observed among EPA Partners and large emitters

. The paper is organized in to the following sections:

 Section 2 describes the methodology used to look at trends in F

- GHG emissions.

 Section 3 pr esents the results of the analysis and provides a discussion on the observed trends and patterns

.

 Section 4 summarizes the conclusions drawn from the analysis

.

2. Methodology This section describes the data sources and methodology used to analyze trends in U.S. F

- GHG emissions. The section is broken into two sub

- sections. Section 2.1 describes the data sources including the scope of the analysis; and Section 2.2 describes the trends analyzed.

2.1 Data Source s This paper relies on non

- confidential emissions data from the EPA GHGRP in addition to data from EPA voluntary emission reduction programs , which is used to compare the trends observed under the GHGRP to those under the voluntary programs

.
From the mid

- 1990s through the establishment of the GHGRP, companies that were part of EPA’s High GWP Voluntary Programs and Partnerships reported F

- GHG emissions data to EPA either directly or through third parties . This data has been and continues to be used in many EPA and U.S . analyses, such as the Inventory of U.S. Greenhouse Gas Emissions and Sinks (EPA 2014a) and the U.S. Climate Action Report ( U.S. State Department 2014)

. Since 2011, EPA has been collecting F

- GHG emissions data mainly through the GHGRP as oppos ed to relying on voluntarily reported data

. Emissions data from the EPA GHGRP are published by the U.S. EPA and provided for public use in multiple forms . These forms include; 1) summary files of GHGRP data, by year, on the GHGRP website
, 8 2) FLIGHT, a GHGRP data visualization tool

, 9 and 3) the EPA Envirofacts

6 http://www.epa.gov/highgwp/semiconductor

- pfc/index.html
7 http://www.epa.gov/highgwp/electricpower

- sf6/index.html 8 http://www.epa.gov/climate/ghgreporting/ghgdata/reportingdatasets.html 9 http://ghgdata.epa.gov/ghgp/main.do6 Database, a publically available database that is accessible online

. 10 These data

source s contain non

- confidential environmental data reported to EPA through the GHGRP (Envirofacts als o includes data from other EPA regulatory programs). GHG d ata from these sources is represented in either metric tons of GHG, or metric tons of carbon dioxide equivalents ( CO 2 e). 11 EPA applies the Intergovernmental Panel on Climate Change (IPCC) Fourth Asse ssment Report GWP values to convert the reported emissions data into a common unit of mt CO 2 e. 12

Scope of the Analysis
The GHGRP is a threshold based reporting program. Therefore, the trends analy zed and discussed in this paper do not fully represent the en tirety of U.S. F

- GHG emissions from industrial sources . Table 2 below indicates the percentage of the GHG emissions from each source category that are accounted for by facilities covered by the GHGRP.

Table 2

. Percentage of GHG Emissions Accounted for by Facilities Covered by GHGRP By Source Category

Source Estimated Percentage of GHGRP GHG Emissions Coverage a Aluminum Production 100 % Electronics Manufacturing 75

- 90% Magnesium Production and Processing 76

- 77% Use of Electric Transmission and Distribution (ET&D) Equipment 67% Manufacture of Electric Transmission and Distribution (ET&D) Equipment 66%

HCFC

- 22 Production and HFC

- 23 Destruction 100% Production of Fluorinated Gases 100% Source: EPA, 2014 b

a Cov erage estimates include both F

- GHGs and other GHGs emitted from these sources. To avoid introducing trends caused by changes in the set of facilities reporting in any given year, this analysis focuses on facilities that have reported their emissions to the GHGRP for all of the years from 2011 through 2013 and whose emissions have been verified . These facilities represented between 8 5 and 100 percent of GHGRP

- reported emissions for their source categories, depending on the year and the industry.

10 http://www.epa.gov/envirofw/ 11 GHG data is reported to the U.S. EPA in metric tons of GHG; EPA then converts this to CO 2 e using consistent GWPs. The sole exception is the data received from fluorinated gas produ cers, as discussed below. 12 The analysis relies on global warming potential values from Table A

- 1 of Subpart A of 40 CFR Part 98. http:/ /www.ecfr.gov/cgi

- bin/text

idx?SID=af924f3ef4d2068f574eb6c4c102364a&node=ap40.21.98_19.1&rgn=div9 These are reflective of the GWPs published in the IPCC Fourth Assessment Report (IPCC, 2007)7 2.2 Trends Analy zed The granularity of emissions data provided by the GHGRP enables U.S. F

- GHG emissions data to be grouped and analyzed in several ways

. This paper investigates the groupings/trends as presented in Table 3

.

Table 3

. Analysis Groupings of GHGRP F

- GHG Data Trend Gas Type SourcePFCsHFCsSF6NF3All F-GHGsAluminum ProductionElectronics ManufacturingMagnesium ProductionUse of ETD EquipmentManufacture of ETDEquipmentAllFiveF-GHG EmittingSource Categories

Aggregate of F

- GHGs and All Source s X X Aggregate of F

- GHGs for Each Source X X X X X X Each F

- GHG for All Source s X X X X X Each F

- GHG for Each Industry X X X X X X X X X

In order to further analyze the overall trends of the source categories shown in Table 3 , trends for large emitters and trends for GHGRP reporters that are/were Voluntary Program Partners with EPA a re investigated. EPA V oluntary Program Partner companies may or may not be required to report facility

- level emissions under the GHGRP, depending on whether the facility

- level reporting threshold is met.

3. Results and Discussion EPA High GWP Gases Voluntary Program Partnerships have a long track record of

success ; from the inception of these Partnerships

, U.S. F

- GHG emissions reported by EPA Partners have fallen significantly . While the GHGRP is a reporting program and does not require mitigation of GHGs

, the results of this analysis reveal that F

- GHG emissions reported through the GHGRP are also decreasing . This section investigates the trends in repo rted emissions and discusse s potential reasons for why this decrease is occurring. 

## Partners GHGRP Reporters

Figure 2. Overlap of EPA High Gases Voluntary Program Partners and EPA GHGRP Reporters8 This section is broken into t wo sub

- sections

. Section 3. 1 presents overall trends in reported F

- GHG emissions, and focuses on these trends with respect to the various types of F

- GHG s and sources. Second , Section 3. 2 discusses the contributions of various types of reporte rs to GHGRP

- reported F

- GHG emission trends. The types of reporters include EPA Voluntary Program Partners/Non

- Partners and the larger/largest emitters

. 13

Although the emission trends for HCFC

- 22 Production and Production of Fluorinated Gases are discussed briefly in section 3.2 below, these trends are generally not included in the discussion because they are driven by external factors. Specifically, the emi ssion trend for HCFC

- 22 production is affected by the phaseout of the production HCFC

- 22 for non

- feedstock uses under the Clean Air Act and Montreal Protocol, while the emission trend for fluorinated gas production is affected by the use of different GWPs in 2013 than in 2011 and 2012. 14

**3. 1**  **GHGRP F** 

**- GHG**  **Trends (2011**

**- 2013)** 
Figure 3 below shows the trends from all F

- GHG

- emitting source categories other than HCFC

- 22 and f luorinated gas production for 2011 through 2013.

13 For purposes of this paper, larger is defined as above 50,000 m tCO 2 e and largest 100,000 mtCO 2 e. 14 This inconsistency in GWPs is expected to be removed in the near future. To date, fluorinated gas producers have reported their emissions only in terms of CO 2 e under temporary reporting provisions. Under a rule proposed in November, 2013, fluorinated gas producers would report emissions of individual chemicals that exceeded 1,000 mtCO 2 e in tons of that chemical for 2011 and later years, and would report other emissions in CO 2 e using a single set of GWPs.9 Figure 3 . Trends in U.S. GHGRP F

- GHG Emissions (Note: This chart only represents HFC emissions from magnesium production , and does not include HFC emissions from HCFC

- 22 Production/HFC

- 23 Destruction or F

- GHG Production, which are on the magnitude of millions of metric tons CO 2 e per year.)

Th e trends indicated in Figure 3 for the various types of F

- GHGs can be attributed to reductions (or increases) seen for specific sectors. Source

- specific F

- GHG trends are displayed in Figure 4.

Figure 4 . Trends in F

- GHG Emissions, by Source Category

Between 2011 and 2013, U.S. GHGRP F

- GHG emissions from the se five source categories decreased by 1 9 percent (2. 5 MMT CO 2 e) , with a more noticeable drop in emissions between 2011 and 2012 than between 2012 and 2013. Reductions in annual emissions are observe d for all types of F

- GHGs

, with the exception of HFCs (emitted from magnesium and electronics production) , which actually increased by 1 4 percent (0.03 MMT CO 2 e)

. The largest reduction in annual emissions between 2011 and 2013 is seen for SF 6 ( 24 percent
, 1

. 4 MMT CO 2 e) , followed by PFCs ( 16 percent
, 1. 1 MMT CO 2 e) , then NF 3 ( 17 percent
, 0.1 MMT CO 2 e)

. A closer examination of these trends, including consideration of underlying activity levels and emission factors, follows.10 F

- GHG Specific Trends

**SF 6**  **Trends** : Reductions in annual SF 6 emissions are driven mainly by reductions in emissions from the use of electrical transmission and distribution ( ET&D ) equipment and magnesium production. These reductions have occurred despite increased activity levels in both of these source categories.
Electrical equipment use , the largest source of SF 6 emissions in the U nited S tates , saw SF 6 emissions decrease by 2 5 percent from 2011 to 20 13 ( 0. 9 MMT CO 2 e , mor e than half of the SF 6 reductions ). This reduction was driven by a 33

- percent reduction in the emission factor for this source category ( SF 6 emissions per unit of installed nameplate capacity )

, which declined from 3. 4 percent in 2011 to 2. 6 percent in 2012 and then 2. 3 percent in 2013. (See Table 8 below for a more detailed analysis of these reductions.) This indicates that the absolute reductions in SF 6 emissions are a result of emission mitigation measures

. The drop in emissions and in the emission s factor from the use of ET&D equipment is a continuation of a trend observed through EPA’s SF 6 Emission Reduction Partnership for Electric Power Systems. Partners comprise approximately 75 percent of the ET&D facilities required to report to the GHGRP , an d they comprise 65 percent of the nameplate capacity of ET&D reporters

. 15 However, while the trend in emission reductions is continuing for Partners , much of th e reduction seen in GHGRP data is coming from utilities that are not participants in the EPA Volu ntary Program Partnership. Non

- Partners account for 45 percent of emission reductions (0.41 MMTCO2e) although they represent 35 percent of GHGRP reporter nameplate capacity

. As discussed further in section 3.2, non

- Partners may be making relatively large reductions as they take advantage of relatively large and/or inexpensive emission reduction opportunities (i.e., “low hanging fruit

, ” such as replacing major leaking circuit breakers) that Partners have already taken advantage of under the voluntary progra ms

. Manufacturing of electrical equipment is a smaller source of SF 6 but contributed significantly to the observed decrease in SF 6 emissions, with emissions falling by 0.15 MMTCO 2 e between 2011 and 2013. This corresponds to a decrease in the industry

wide emission factor (SF 6 emission/quantity of SF 6 delivered in new equipment) from 20 percent in 2011 to eight percent in 2013, again indicating that facilities are taking actions to reduce and manage emissions.

Sulfur hexafluoride emissions from m agnesium pr oduction and processing fell by 24 percent (or 0.31 MMT CO 2 e) from 2011 to 2013

. This decline occurred despite the fact that magnesium production and processing levels in the U.S. for GHGRP reporters

15 Based on 2013 b eginning

- of

- the year

- nameplate capacity.11 have increased since 2011 as the industry has recovered from the recession an d automotive parts have relied increasingly on lighter metals, such as magnesium, as opposed to steel. 16 GHGRP data indicates that the industry is shift ing from using SF 6 as a cover gas to HFC

- 134a (as well as other low GWP cover gases such as FK5

- 1

- 12) because of environmental concerns related to SF 6 as an extremely potent GHG as well as potential other factors such as price (Ricketts et. al.)

. **PFC Trends :**  Figure 3 indicates an overall decrease of annual PFC emissions from 2011 to 201 3. These reductions are mainly being driven by reductions from electronics manufacturing ( 0.5 6 MMT CO 2 e , an 18 percent decline ), and aluminum production ( 0.5 0 MMT CO 2 e , a 14 percent decline )

. The decreases appear to result partly, but not completely, from reductions in activity.
In regards to electronics manufacturing, the annual production, in terms of produced substrate area , reported to the GHGRP decreas ed from 2011 to 2013. Activity for el ectronics manufacturing may also be tracked using an indicator referred to as total manufactured layer area (TMLA). TMLA is the product of the number of layers that comprise different kinds of semiconductors devices, including both silicon wafer and metal interconnect layers, and silicon consumption (i.e., the area of semiconductors produced). As technologies progress and chips need to become faster and smaller, the number of layers increases. TMLA may be a better indicator of F

- GHG emissions because as the number of layers increase, the number of F

- GHG using process steps also increases. According to data reviewed from the International Semiconductor Technology Roadmap (ITRS), 17 the number of layers for different technology types and nodes has remained consi stent between 2011 and 2013. Therefore, one can assume that the TMLA trend would align with the trend of decreasing produced area of substrate from 2011 to 2013 for GHGRP reporters. These activity reductions align with reductions in electronics manufacturi ng PFC emissions. Therefore

, some of the reductions may be a result of decreasing activity. Additionally, r ecent testing and research indicate better practices for abatement system maintenance and operation are being employed, leading to reductions in F

- GHG emissions from electronics manufacturing (Davia et. al. 2013). However, this appears not to have had a s large of an impact as the trend in activity.
Table 4 shows the trends in primary aluminum production, emissions, and emission factors between 2011 and 2013.

16 Due to limitations on use of confidential business information collected through the EPA GHGRP, it is not possible to publish production data for magnesium production. While the United States Geologic Survey publ ishes a subset of magnesium production data in its Minerals Yearbook (it does not publish primary production information), this data may not correspond to the same population of companies that are reporting through the GHGRP. 17 http://www.itrs.net/12 Table 4 . Trends in U.S. Aluminum Production, Emissions, and Emission Factors (2011

- 2013) 2011 2012 2013 Production (ktonnes) 18 1,986 2,070 1,948 GHGRP Emissions (MMTCO2e) 3.5 2.9 3.0 Emission Factor (tCO2e/tonne Al) 1.7 1.4 1.5

As shown in Table 4, PFC emissions from aluminum production declined significantly between 2011 and 2012, driven by a significant decrease in the average emission factor. However, the emission factor in 2011 was unus ually large for recent years , as can be seen in Figure 6, below, which includes data reported by EPA Partners in the two decades before 2011

. (This data reflects reports from all but one U.S. aluminum production facility.) The increase in 2011 was due to atypically large emissions for at least one alum inum facility during production start

- up. Both emissions and the emission factor increased slightly between 201 2 and 2013

. Therefore, it does not appear that the reductions between 2011 and 2013 are being driven by long

- term changes in GHG management pract ices. However, as shown by Figure 6 and as discussed further below, most primary aluminum producers had already instituted GHG management practices and achieved significant emission reductions before they began to report under the GHGRP.

**NF 3**  **Trends :**  NF 3 i s used in electronics manufacturing to clean chemical vapor deposition chambers. Emissions resulting from the use of NF 3 have decreased from 2011 to 2013. This is due to the same trends driving PFC emissions from electronics manufacturing , described above.

**HFC Trends:**  HFCs are the only type of F

- GHGs from the five source categories studied here for which annual emissions are increasing. However, because HFCs make up only two percent of the emissions from these source categories, the reductions of the other types of F

- GHGs dominate the trend. HFCs are used in electronics manufacturing and magnesium production. HFCs emissions actually decre ased between 2011 and 2013 for electronics manufacturing (20 percent, 0.04 MMT CO 2 e). However

, this was counterbalanced by an increase in HFC emissions from magnesium production (increase of 443 percent, or 0.07 MMT CO 2 e)

. This is a result of switching from the use of SF 6 cover gas to HFC

- 134a cover gas by one large producer in 2013. While this transition increased HFC emissions from magnesium production, it is important to note that it decreased overall fluorinated GHG emissions in CO 2 e, because the GWP of H FC

- 134a is one sixteenth that of SF 6
. It is also important to note that the HFC emissions from electronics and magnesium production are a small fraction of the HFC emissions from the three major sources of

18 Alumi num production data is provided by the United States Geologic Survey Minerals Yearbook ( http://minerals.usgs.gov/minerals/pubs/commodity/aluminum/index.html#myb )13 HFCs, which include HCFC

- 22 production, other flu orinated gas production, and, most important, substitution for ozone

- depleting substances. HFCs are replacing ozone

depleting substances as refrigerants, aerosol propellants, solvents, and fire retardants

. 19 These uses of HFCs are covered by other regulatory programs, and hence are not analyzed as part of this paper. 20

**Emissions from Producers of HCFC**

**- 22 and Other Fluorinated Gases** 
Figure 5 shows the emission trends for producers of HCFC

- 22 and other fluorinat ed gases.

Figure 5 . Trends in F

- GHG Emissions from HCFC

- 22 and Other Fluorinated Gas Production
As discussed above, these trends are affected by factors other than emission factors per unit of activity. Specifically, the upward trend observed in emissio ns from fluorinat ed gas production is likely to be at least partially attributable to the GHGRP’s adoption of AR4 GWPs in 2013, which for F

- GHGs are 18 percent higher, on average, than the SAR GWPs used previously for reporting. The downward trend in emiss ions from HCFC

- 22 production is at least partially attributable to the phaseout of HCFC

- 22 production for non

- feedstock uses that is occurring under the Clean Air Act and Montreal Protocol.

**3. 2**  **Observed Trends for Various**  **Types of GHGRP**  **Reporters**

Previous analyses performed on GHGRP data (e.g., to include this data in the Inventory of U.S. Greenhouse Gas Emissions and Sinks ) have indicated that the F

- GHG emission

19 http://www.e pa.gov/climatechange/ghgemissions/gases/fgases.html 20 http://www.epa.gov/ozone/title6/index.html14 patterns of facilities differ based on : (1) participation in EPA’s High

- GWP Gases Voluntary Program Partnerships , and (2) the magnitude of the total F

- GHG emissions reporte d by the facility

. We therefore examined these two characteristics and their impacts on emissions and emission factors in this study. This examination showed l a rger percentage reductions for reporters that did not participate in the EPA Partners hips and for reporters with relatively high magnitudes of reported emissions. While EPA Partners account for the majority of reported F

- GHG emissions (between 67 percent and 71 percent ), these reporters are not necessarily also the same set of reporters that are the large r and largest emitters

.

Table 5 . Trends in F

- GHG Emissions Reported by Large r Emitters (2011

- 2013), 50,000 mtCO 2 e threshold

Reporter Type F

- GHG Emissions (MMT CO 2 e) 2011

– 2013 Reduction (MMT CO 2 e) Percent Reduction
2011 2012 2013 Total GHGRP Reporters (5 source categories) 13. 1 11. 3 10.6 2. 5 1 9 % Large r (based on 2011 data) 11. 0 8

. 1 7. 5 3. 5 3 2 % Large r (based on 2013 data) 9. 9 7.8 7.6 2. 3 24 %

Table 6 . Trends in F

- GHG Emissions Reported by Large st Emitter s (2011

- 2013), 100 ,000 mtCO 2 e threshold

Reporter Type F

- GHG Emissions (MMT CO 2 e) 2011

– 2013 Reduction (MMT CO 2 e) Percent Reduction 2011 2012 2013 Total GHGRP Reporters (5 source categories) 13. 1 11. 3 10.6 2. 5 1 9 % Large st (based on 2011 data) 9.0 7. 2 6. 7 2

. 3 25 % Large st (based on 2013 data) 7.8 6 .8 6.4 1.4 1 8 %

Tables 5 and 6 show the trends for the “larger” and “largest” emitters, where thresholds for defining these categories are 50,000 mtCO 2 e and 100,000 mtCO 2 e respectively. These thresholds are applied for both the reporting years 2011 and 2013. 21 The data indicate that the reductions , in percentage terms, of the “larger” and “largest” emitters in 2011 are higher than the average reductions of all reporters. This pattern persists for the “larger” reporters in 2013, although it does not persist for the “largest” reporters in 2013, whose average reductions are one percentage point lower than the average for all GHGRP reporters.

21 By definition, facilities with downwardly trending emissions have larger emissions in earlier years than in later years, and facilities with upwardly trending emissions have larger emissions in later years than in earlier years. Thus, studying the facilit ies with the largest emissions in 2011 may over

- represent facilities with downwardly trending emissions, while studying the facilities with the largest emissions in 2013 may
over
- represent facilities with upwardly trending emissions. For this reason, we st udied both sets here.15 Table 7 . Trends in F

- GHG Emissions Reported under the GHGRP by EPA Voluntary Program Partner s and Non

- Partner s (2011

- 2013)

Reporter Type F

- GHG Emissions (MMT CO 2 e) 2011

– 2013 Reduction (MMT CO 2 e) Percent Reduction 2011 2012 2013 Total GHGRP Reporters (4 source categories with Partnerships) 12.8 11. 1 10. 4 2. 3 1 8 %

Partners 8.7 7. 7 7 .5 1.2 14 %
Non

- Partners 4.1 3.4 3.0 1.1 27 %

Table 7 presents the trends in F

- GHG emissions reported under the GHGRP by EPA Voluntary Program Partner s and Non

- Partners for 2011 through 2013. The results in this table indicate that Non

- Partners are contributing nearly as much to total reductions as Partners, although they account for less than half of the emissions and activity in each of the four source categories with P artnerships. The percentage by which the Non

- Partners reduced emissions between 2011 and 2013 is almost twice as large as the percentage by which the Partners reduced emissions.

For one source category, use of ET&D equipment, activity data are publicly available, allowing a closer examination of emission factors among facilities that are Partners,

non
- Partners, “larger,” and “largest.” This examination sheds light on a possible reason for the patterns observed above. Table 8 shows the emission factors of the various types of ET&D reporters from 2011 through 2013.

Table 8 . Trends in Emission Factors for Users of ET&D Equipment (2011

- 2013)

Reporter Type SF 6 Emission Factor ( kg Emissions/k g Nameplate Capacity) 2011

- 2013 Reduction in

Emission

Factor (kg/kg) Percent Reduction in

Emission

Factor

2011 2012 2013

Total GHGRP ET&D Reporters 0.034 0.026 0.023 0.011 33%

EPA Partners 0.029 0.023 0.020 0.009 32%

Non

- Partners 0.043 0.031 0.028 0.015 35%

Larger (based on 2011 data) 0.047 0.032 0.028 0.019 41%

Largest (based on 2011 data) 0.059 0.038 0.032 0.027 46%16 In general, Table 8 shows that the facilities with the largest average emission factors in 2011 made the largest reductions in their emission factors between 2011 and 2013. This is an expected result. Facilities that have already attained relatively low emission factors are likely to have fewer options remaining to them to make further reductions than facili ties that have relatively high emission factors . For example, EPA Partners have been conducting e missions mitigation activities throughout the lifetime of the Partnerships. Thus, they are likely to have already taken advantage of the options with the largest and least expensive reductions. Nevertheless
, as shown in Table 8, Partners have continued to reduce their average emission factor . In addition to ongoing efforts to replace leaking equipment, Partner companies are working to further their emission reductions by advancing their mitigation strategies

— for example, examining their system for all possi ble sources

— large and small

-- of emissions; purchasing new laser leak detection cameras; working with their vendors to receive SF 6 inventory related reports; tightening gas cylinder inventories; and operating more recycling carts (EPA 2014d).
Comparison of GHGRP Trends to the Trends Reported Under the Partnerships
Figure 6, below, plots data on emission rates from three p artnerships, 22 normalized to the start year of each program

.

Figure 6. Emission Rates of Partner Companies Compared to Base Year

Several conclusions can be drawn from the figure.

22 The emission factors for electric power systems and semiconductors are based on the Partners’ reported nameplate capacity and estimated TMLA, respectively. The emission factor for aluminum is based on industry

- wide emissions and pro duction, which are similar to the emissions and production reported by the Partners. (Only one aluminum facility was not a Partner.)

0.00 0.20 0.40 0.60 0.80 1.00 1.2019901991199219931994199519961997199819992000200120022003200420052006200720082009201020112012

Aluminum Electric Power Systems Semiconductors17 • First, as noted above, the reductions in emission factors made by Partners over the last two decades have been deep and lasting, exceeding 75 percent for all three industries

.

• Second, three years into the voluntary program for each industry, the point comparable to 2013 for the GHGRP ( the third year of reporting) , the emission factors for electric power systems and aluminum had declined by 13 and 22 percent, respectively. (The estimated emission factor for semiconductors did not begin to decline until emission reduction options, such as the replacement of C 2 F 6 with NF 3 for chamber cleaning, began penetrating the market, but at that point the emission factor fell sharply.) The comparable reductions in the

em ission factors for electric power systems and aluminum under the GHGRP

are 33 percent and 13 percent, respectively

.

• For electric power systems, the percentage reduction in the emission factor was higher three years into the GHGRP than three years into the voluntary program. However, because the 1999 emission factor was nearly four times as large as the 2011 emission factor, the absolute reduction in the emission factor was higher three years into the voluntary program than three years into the GHGR P

. Interestingly, after slowing in 200 9 and 20 10
, the reductions achieved by electric power system Partners have accelerated since the GHGRP became effec tive. It is possible that this trend is attributable to the fact that the GHGRP, as a mandatory and economy

- wide reporting program, has more visibility and weight than the reporting done through EPA’s Voluntary Programs. However, as discussed below, this t rend is not observed for aluminum and semiconductor production.

• As noted above, the decrease in the emission factor for aluminum under the GHGRP is an artifact of an unusually high emission factor in 2011. In general, f or aluminum and semiconductor produc tion , the percent reductions as well as absolute reductions in emission factors appear to have leveled off in recent years

. For these two source categories
, the reductions achieved under the GHGRP by the Partners appear to be smaller than those achieved ea rlier under the Partnerships, perhaps limited by the availability of low

- cost emission reduction options.
Possible Explanations for the Trends
**More accurate or improved data collection practices**

. An alternative explanation for the trends discussed above is that they are intro duced by improvements in data collection and emissions estimation that occur over time. In the first year of data18 collection under the GHGRP, reporters had the option to rely on alternative monitoring methods (known as “Best Available Monitoring Methods” or BAMM) if the newly covered facility was unable to acquire, install, and operate the required monitoring equipment. This provision was permitted to facilities for a limited amount of time, recognizing that adjustments to respond to t he new regulation may require additional time in order to minimize impacts to normal business operations (EPA, 2014c). For the first year or reporting in 2011, 26 percent of reporters used BAMM. This percentage dropped to zero in 2012 and 2013. 23 As a resu lt, the first year of reported emissions may include estimates that do not all meet the accuracy requirements set forth under the GHGRP.
Additionally, reporters have become more familiar with their data and the required emissions monitoring and calculation practices since 2011. GHGRP reporters that were not EPA Voluntary Program Partners did not have institutional knowledge of emission estimation practices at the outset of the GHGRP

. 24 As noted above, about half of overall F

- GHG reductions (1.2 7 MMT CO 2 e) fro m 2011

- 2013 are attributed to GHGRP reporters that were not part of the EPA’s High GWP Gases Voluntary Program Partnerships.
In general, errors in estimating emissions are expected to have been equally likely to result in over

- or underestimates in 2011, making it unlikely that such errors are a significant driver of the observed emission trends. One possible exception to this is the trend for electric transmission and distribution equipment. One of the issues that has arisen during the implementation of the GHGRP for this source category is that overcharging of new equipment is common, and such overcharging results in an overestimate of emissions. (This is because new equipment is being charged with a quantity of SF 6 that is greater than its nameplate cap acity, and the emission estimation method for this source category relies on the assumption that the quantity charged equals its nameplate capacity). As facilities learn that overcharging results in an overestimate of emissions, they may be overcharging le ss frequently, resulting in an apparent (but not a real) reduction in emissions. However, by itself, this is not expected to have resulted in reductions of the magnitude observed.

**Increased reporter**  **awareness of facility emissions**

**.** Once it is conclude d t hat the observed decreases in emissions and emission factors are real, the question becomes what is driving them. One possibility is increased reporter awareness of facility emissions. In some cases, facilities that have not previously tracked emissions ma y not have been aware of their magnitude until they began tracking and reporting the

23 This includes facilities that report emissions from production of electronics, fluorinated gases, magnesium, and electri cal equipment, as well as from use of electrical equipment. . 24 Subparts F, T, and DD (Aluminum Production, Magnesium Production, and Use of ET&D) of the EPA GHGRP relies upon the same emission estimation method Partners used to estimate and report emissio ns as part of the EPA Voluntary Program. Subpart I (Electronics Manufacturing) relies on similar methods as used by some EPA Partners.19 emissions under the GHGRP. Once facilities are alerted to their emissions, they may take action to control them due to concerns regarding public reaction (discussed furthe r below), cost control (particularly when the emitted chemical is a valuable commodity), or a desire to be good stewards of the environment. As discussed above, tracking of emissions has been an important part of EPA’s voluntary emission reducti on partners hip programs for these reason s

. **Increased public awareness of facility emissions**

. As noted above, facilities may also reduce emissions because they are concerned about possible public reaction to them. The GHGRP is a recently established yet well

- publicize d national program that, among other purposes, provides the public with access to GHG emissions information. Programs that provide facility

- level emissions information to the public (so called “Right

to

- Know” laws) may incentivize companies to reduce those emissions (Mastromonaco 2013 ; Konar and Cohen 1997 ). The Emergency Planning and Community Right to Know Act (EPCRA) is a classic example of a “Right

- to

- Know” law in the United States. Under this law, EPA created the Toxic Release Inventory (TRI), a progra m that requires firms to annually report information on their emissions of a variety of pollutants, which is then made available to the public. Since the inception of the TRI, emissions of the pollutants covered by this program have decreased, for example in the last decade by approximately 30 percent. Studies have drawn different conclusions regarding whether public pressure has influenc ed these reductions (Mastromonaco 2013 ; Konar and Cohen 1997 ). Nonetheless, in today’s world of corporate social responsi bility, shareholders and other stakeholders view environmental issues, such as climate change, as being within the scope of a company’s responsibilities; they are demanding greater transparency on the social and environmental impact of a company’s activiti es (Noked 2013). Public pressure may be a reason for reduced annual F

- GHG emissions in the United States. By making a concerted effort to reduce emissions (e.g., through process optimization, improved gas management, or end

- of

- pipe controls) , facilities ca n contribute to improvements in their corporate reputation.

4. Conclusions The SF 6 , PFC, and NF 3 emissions reported to the GHGRP from production of aluminum, semiconductors, magnesium, and electrical equipment, as well as from use of electrical equipment

, have decreased since 2011, whereas the reported (much smaller) HFC emissions from these source categories have increased over the same time period. The overall decrease in emissions appears to be attributable to reductions in emission factors in some cases and reductions in activity levels in others.

Further examination of the root causes of the decrease in F

- GHG emissions reveals that 1 ) the largest reductions can be attributed to very large emitters
, and 2 ) N on
Partners contribute more to emission reduct ions than would be expected based on their20 activity levels and emissions. For electric power systems, these patterns are clearly related to the relatively high emission factors for very large emitters and for Non

Partners in 2011; these high emission fact ors imply that very large emitters and Non

Partners ha d not implemented emission reduction options to the extent that smaller emitters and Partners had in that year . In general, the apparent widespread use of emission reduction options since 2011 may be a ttributable to increased reporter and public awar eness of facility GHG emissions . Furthermore, facilities may be able to manage their systems more effectively now that they are required to report on process inputs and resulting emissions, a concept often e xpressed by the adage, “What gets measured gets managed.”
This analysis of early

- reported GHGRP F

- GHG emissions data is telling. However, as the GHGRP continues , including additional years of data will help to validate the conclusions drawn about the early

- reported F

- GHG emission trends in this paper. T he trends observed to date should be revisited after another few years of data are collected to see whether these patterns continue or change

. Additionally, in light of the rise in atmospheric concentrations of F

- GHGs (Figure 1), it will be important to reexamine reporting trends to see whether reductions in reported U.S. F

- GHG emissions continue to be observed and to investigate any inconsistenc ies between the emission trends reported for the U.S. and other countries versus atmospheric measurements.

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( U

. S

. State Department 2014 ). 2014 United States Climate Action Report . Washington, D.C., United States. United States State Department; [cited September 2014]. Available from: http://www.state.gov/documents/organization/219038.pdf22 Table(s)

Table 1 . Summary of EPA Categories of F

- GHG Emitters Subject to the GHGRP

Table 2 . GHGRP Emissions Coverage for F

- GHG Emit ting Sources

Table 3 . Analysis Groupings of GHGRP F

- GHG Data

Table 4 . Trends in U.S. Aluminum Production, Emissions, and Emission Factors (2011

- 2013)

Table 5 . Trends in Larger Emitter Reported F

- GHG Emissions (2011

- 2013), 50,000 mtCO2e threshold

Table 6

. Trends in Largest Emitter Reported F

- GHG Emissions (2011

- 2013), 100,000 mtCO2e threshold

Table 7 . Trends in EPA Voluntary Program Partner and Non

- Partner GHGRP Reported F

- GHG Emissions (2011

- 2013)

Table 8 . Trends in Emission Factors for Users of ET&D Eq uipment (2011

- 2013)23 Figure Captions
Figure 1. Atmospheric Concentration Trends of SF 6 (used in electric power systems, magnesium production, and electronics manufacturing) and NF 3 (mainly used in electronics manufacturing).
Figure 2. Overlap of EPA High G ases Voluntary Program Partners and EPA GHGRP Reporters
Figure 3. Trends in U.S. GHGRP F

- GHG Emissions
Figure 4. Trends in F

- GHG Emissions, by Source Category
Figure 5. Trends in F

- GHG Emissions from HCFC

- 22 and Other Fluorinated Gas Production
Figure 6. Emission Rates of Partner Companies Compared to Base Year