Chapter 3: Chemical Industry Emissions

CHAPTER 3

CHEMICAL INDUSTRY EMISSIONS

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AuthorsS e c tions 3.3
Retno Gumilang Dewi (Indonesia) and María José López Blanco (Spain)S e c tions 3.10
Karen S. Schaffner (USA), Deborah A. Ottinger (USA) and Brian T. Mader (USA)S e c tions 3.11
Håkon Frøysa Skullerud (Norway), Katsuhiko Hirose (Japan) and Samir Tantawi (Egypt)Contributing Authors
S e c tions 3.10
Jeffrey B. Coburn (USA) and Gregory M. Watson (USA)S e c tions 3.11
Richard Chahine (Canada), Shohei Oyama (Japan) and Nigel Brandon (UK)

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Chapter 3: Chemical Industry Emissions

Contents
3 Chemical Industry Emissions ......................................................................................................................... 3.8
3.1

Introduction ......................................................................................................................................... 3.8

3.2

Ammonia Production .......................................................................................................................... 3.8

3.3

Nitric Acid Production ........................................................................................................................ 3.8
3.3.1 Introduction ................................................................................................................................... 3.8
3.3.2 Methodological issues ................................................................................................................... 3.8
3.3.2.1

Choice of method ............................................................................................................... 3.8

3.3.2.2

Choice of emission factors ................................................................................................. 3.8

3.3.2.3

Choice of activity data...................................................................................................... 3.10

3.3.2.4

Completeness ................................................................................................................... 3.10

3.3.2.5

Developing a consistent time series ................................................................................. 3.10

3.3.3 Uncertainty assessment................................................................................................................ 3.10
3.3.4 Quality Assurance/Quality Control (QA/QC), Reporting and Documentation ........................... 3.10
3.4

Adipic Acid Production..................................................................................................................... 3.11

3.5

Caprolactam, Glyoxal and Glyoxylic Acid Production ..................................................................... 3.11

3.6

Carbide Production............................................................................................................................ 3.11

3.7

Titanium Dioxide Production ............................................................................................................ 3.11

3.8

Soda Ash Production ......................................................................................................................... 3.11

3.9

Petrochemical and Carbon Black Production .................................................................................... 3.11

3.10

Fluorochemical Production ............................................................................................................... 3.12

3.10.1 HFC-23 emission from HCFC-22 production ............................................................................. 3.12
3.10.1.1 Introduction ...................................................................................................................... 3.12
3.10.1.2 Methodological issues ...................................................................................................... 3.12
3.10.1.3 Uncertainty assessment .................................................................................................... 3.20
3.10.1.4 Quality Assurance/Quality Control (QA/QC), Reporting and Documentation ................ 3.21
3.10.2 Emissions from production of fluorinated compounds (other than HFC-23 emissions from HCFC22 production) ............................................................................................................................. 3.21
3.10.2.1 Introduction ...................................................................................................................... 3.21
3.10.2.2 Methodological issues ...................................................................................................... 3.22
3.10.2.3 Uncertainty assessment .................................................................................................... 3.31
3.10.2.4 Quality Assurance/Quality Control (QA/QC), Reporting and Documentation ................ 3.32
3.11

Hydrogen Production ........................................................................................................................ 3.33

3.11.1 Introduction ................................................................................................................................. 3.33
3.11.2.2 Choice of emission factors ............................................................................................... 3.47
3.11.2.3 Choice of activity data...................................................................................................... 3.48
3.11.2.4 Completeness ................................................................................................................... 3.49
3.11.2.5 Developing a consistent time series ................................................................................. 3.49
3.11.3 Uncertainty assessment................................................................................................................ 3.49
3.11.3.1 Emission factor uncertainties ........................................................................................... 3.49
3.11.3.2 Activity data uncertainties ................................................................................................ 3.50
3.11.4 Quality Assurance/Quality Control (QA/QC), Reporting and Documentation ........................... 3.50

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3.11.4.1 Quality Assurance/Quality Control .................................................................................. 3.50
3.11.4.2 Reporting and Documentation.......................................................................................... 3.51
Annex 3A.1 Default emission factors for section 3.10.2 Emissions from production of fluorinated compounds(other than HFC-23 emissions from HCFC-22 production) .............................................................. 3.52
Reference

3.4..................................................................................................................................................... 3.74

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Chapter 3: Chemical Industry Emissions

Equations
Equation 3.30

Tier 1 calculation of HFC-23 from HCFC-22 (produced) using default factor ........ 3.13

Equation 3.31

Tier 2 calculation of HFC-23 from HCFC-22 (produced) using factor(s) calculated
from process efficiencies .......................................................................................... 3.13

Equation 3.32

Calculation of HFC-23 emission factor from carbon balance efficiency .................. 3.13

Equation 3.33

Calculation of HFC-23 emission factor from fluorine balance efficiency ................ 3.14

Equation 3.34

Tier 3a calculation of HFC-23 emissions from individual process streams (direct
method) ..................................................................................................................... 3.14

Equation 3.35 (Updated) Tier 3b calculation of HFC-23 emissions from individual process streams using a siteor process-specific emission factor ........................................................................... 3.14
Equation 3.36

Tier 3c calculation of HFC-23 emissions from individual process streams (bymonitoring reactor product) ...................................................................................... 3.15

Equation 3.37

Tier 3a calculation of ‘instantaneous’ HFC-23 emissions in an individual process
stream (direct method) .............................................................................................. 3.15

Equation 3.38 (Updated) Tier 3b calculation of HFC-23 emissions in an individual process stream using a siteor process-specific emission factor ........................................................................... 3.16
Equation 3.39 (Updated) Tier 3b calculation of standard emission for emission factor-based method ............ 3.16
Equation 3.40

Tier 3c calculation of HFC-23 emissions from an individual facility by in-process
measurement ............................................................................................................. 3.17

Equation 3.41

Tier 1 calculation of production-related emissions ................................................... 3.23

Equation 3.41a (New)

Tier 2 calculation of production-related emissions using a mass balance approach . 3.23

Equation 3.41b (New)

Tier 3 summation of production-related emissions from process vents and equipment
leaks .......................................................................................................................... 3.24

Equation 3.42 (Updated) Tier 3 direct calculation of production-related emissions from process vents .......... 3.24
Equation 3.43 (Updated) Tier 3 calculation of production-related emissions from process vents using a site- orprocess-specific emission factor ............................................................................... 3.24
Equation 3.43a (New)

Tier 3 calculation of emissions from equipment leaks using a screening ranges
approach .................................................................................................................... 3.25

Equation 3.43b (New)

Tier 3 calculation of emissions from equipment leaks using a correlation approach 3.26

Equation 3.43c (New)

Tier 3 calculation of a unit-specific correlation ........................................................ 3.26

Equation 3.43d (New)

Tier 3 calculation of emissions from equipment leaks using a unit-specific correlation
approach .................................................................................................................... 3.26

Equation 3.43e (New)

Tier 3 calculation of production-related emissions from equipment leaks ............... 3.27

Equation 3.44 (New)CO2 emissions from hydrogen production – Tier 1c................................................. 3.43

Equation 3.45 (New)CO2 emissions from hydrogen production – Tier 1b ................................................ 3.43

Equation 3.46 (New)CO2 emissions from hydrogen production – Tier 1a................................................. 3.43

Equation 3.47 (New)CO2 emissions from hydrogen production – Tier 2c................................................. 3.44

Equation 3.48 (New)CO2 emissions from hydrogen production – Tier 2b ................................................ 3.44

Equation 3.49 (New)CO2 emissions from hydrogen production – Tier 3c................................................. 3.44

Equation 3.50 (New)CO2 emissions from hydrogen production – Tier 3b ................................................ 3.45

Equation 3A.1.1 (New) Emissions prior to control for production and transformation processes .................. 3.60

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FiguresFigure 3.16

Decision tree for HFC-23 emissions from HCFC-22 production (or other similar byproduct emissions from fluorochemical production) ................................................ 3.18

Figure 3.17 (Updated)

Decision Tree for emissions of fluorinated greenhouse gas from fluorochemical
production processes, applicable to product, by-product, reactant, and fugitive ...... 3.30

Figure 3.18 (New)Hydrogen production via steam reforming with water gas shift reaction ................. 3.40

Figure 3.19 (New)Hydrogen production via gasification with water gas shift reaction ......................... 3.41

Figure 3.20 (New)

Decision tree for estimation of CO2 emissions from hydrogen production .............. 3.46

TablesTable 3.3a (New)Different plant types for the production of HNO3....................................................... 3.9

Table 3.3 (Updated)

Default factors for nitric acid production .................................................................... 3.9

Table 3.28 (Updated)

HFC-23 default emission factors .............................................................................. 3.19

Table 3.28a (New)

Tier 1 default emission factors for fluorochemical production ................................. 3.28

Table 3.28b (New)

Representative chemical composition of the emitted mass ....................................... 3.28

Table 3.29 (New)Current hydrogen production methods – status of development and allocation ofemissions to sector .................................................................................................... 3.37

Table 3.30 (New)

Default feedstock requirement factors and carbon content factors for hydrogenproduction ................................................................................................................. 3.47

Table 3A.1.1 (New)

Destruction efficiency range values used to estimate pre-abatement emissions for
production and transformation processes .................................................................. 3.54

Table 3A.1.2 (New)

Actual emissions from production and transformation process reported by specificfluorinated GHG under Subpart L of the GHGRP (considering controls)(approximately 98 percent of P/T process emissions in metric tonne CO2 equivalent),
metric tonne and metric tonne CO2 equivalent .......... 3.Error! Bookmark not defined.

Table 3A.1.3 (New)

Actual Fluorinated GHG emissions from production and transformation processes
from Subpart L of the GHGRP (considering controls),
by group (metric tonne CO2 equivalent) .................................................................. 3.59

Table 3A.1.4 (New)

Estimated pre-abatement fluorinated GHG emissions from production andtransformation processes from Subpart L of the GHGRP, all DE assumptions (metrictonne CO2 equivalent) ............................................................................................... 3.61

Table 3A.1.5 (New)

Estimated pre-abatement fluorinated GHG emissions from production andtransformation processes from Subpart L of the GHRP (using arithmetic mean of DE
range), by Fluorinated GHG Group (metric tonne CO2 equivalent) ......................... 3.62

Table 3A.1.6 (New)

Actual emissions of specific fluorinated GHG from container venting reported under
Subpart L of the GHGRP, by facility (metric tonne and metric tonne CO2
equivalent) ................................................................................................................ 3.63

Table 3A.1.7 (New)

Production and transformation quantities reported under Subpart OO of the GHGRP(metric tonne) ............................................................................................................ 3.64

Table 3A.1.8 (New)

Estimated pre-abatement fluorinated GHG emissions from production andtransformation processes plus container venting from Subpart L of the GHGRP (using
arithmetic mean of DE range) by facility (metric tonne) .......................................... 3.65

Table 3A.1.9 (New)

Default emission factor for fluorinated production ................................................... 3.66

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Chapter 3: Chemical Industry Emissions

Table 3A.1.10 (New)

Ratios of estimated pre-abatement emissions in metric tonne CO2 equivalent (using
arithmetic mean of DE range) to actual emissions in metric tonne of CO2
equivalent .................................................................................................................. 3.67

Table 3A.1.12 (New)Top-10 emitted specific fluorinated GHG, from production processes, transformation
processes, and container venting from Subpart L of the GHGRP (using arithmetic
mean of DE range endpoints).................................................................................... 3.71

Table 3A.1.13 (New)Distribution assumptions for the DE ranges ............................................................. 3.71

Table 3A.1.14 (New)Comparison of emission factor values in parallel analyses ....................................... 3.73

Boxes
Box 3.14

Plant measurement frequency ................................................................................... 3.20

Box 3.15 (New)Definitions ................................................................................................................ 3.36

Box 3.16 (New)Double counting, completeness and cross-cutting allocation ................................... 3.38

Box 3.17 (New)

Production and use of hydrogen carriers ................................................................... 3.39

Box 3.18 (New)

Chemical reactions in hydrogen production by complete oxidation technologies .... 3.41

Box 3.19 (New)

Syngas ....................................................................................................................... 3.42

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3 CHEMICAL INDUSTRY EMISSIONS
Users are expected to go to Mapping Tables in Annex 5, before reading this chapter. This is required tocorrectly understand both the refinements made and how the elements in this chapter relate to the corresponding
chapter in the 2006 IPCC Guidelines.

3.1

INTRODUCTION

No refinement.

3.2

AMMONIA PRODUCTION

No refinement.

3.3

NITRIC ACID PRODUCTION

3.3.1

Introduction

No refinement.

3.3.2

Methodological issues

Introduction – No refinement.

3.3.2.1

C HOICE OF METHOD

No refinement.

3.3.2.2

C HOICE OF EMISSION FACTORSTIER 1 METHOD
It is good practice to use the highest emission factor based on the technology type shown in Table 3.3 and toassume that there is no abatement of nitrous oxide (N2O) emissions.

TIER 2 METHOD
If plant-level factors are not available, it is good practice to use default factors. These default values often
represent midpoint or mean values of data sets (as determined by expert analysis). The extent to which they
represent a specific plant’s emission rate is unknown. Default factors in Table 3.3 should be used only in cases
where plant-specific measurements are not available.
Table 3.3 includes emission factors for N2O, and associated uncertainties by type of production process.
The five production process types are distinguished according to the pressures applied in the oxidation andabsorption stage as presented in Table 3.3a (new).

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TABLE 3.3A (NEW)DIFFERENT PLANT TYPES FOR THE PRODUCTION OF HNO31
Type

Operation Condition

L/L

Single Low Pressure

L/M

Dual Low/Medium Pressure

M/M

Single Medium Pressure

M/H

Dual Medium/High Pressure

H/H

Single High Pressure

Applied Pressure in Bar
Oxidation

Absorption
0 - 1.7<1.7

1.7 – 6.5
1.7 - 6.5

1.7 – 6.5

6.5 - 13
6.5 - 13

Source:1

EC, 2007 (with reference of EFMA, 2000 and Schöffel, 2001)

The factors listed in Table 3.3 for plants using abatement technology, incorporate the effect of N2O abatement
measures. To use these factors, inventory compilers should verify that the abatement technology is installed at
individual plants and operated throughout the year.

TABLE 3.3 (UPDATED)DEFAULT FACTORS FOR NITRIC ACID PRODUCTION
Production Process

N2O Emission Factor(relating to 100 percent pure acid)

Old (pre-1975) plants* (all processes)

10-19 kg N2O/tonne nitric acida

Single low pressure plants

5 kg N2O/tonne nitric acid ±10%

Single medium pressure plants

8 kg N2O/tonne nitric acid ±20%b

Single high pressure plants

9 kg N2O/tonne nitric acid ±40%

Single pressure plants with abatement technology**

2.5 kg N2O/tonne nitric acid ±10%b

Dual Pressure (M/H)

9 kg N2O/tonne nitric acid ±30%b

Dual Pressure (M/H) with abatement technology

2.5 kg N2O/tonne nitric acid ±20%b

Dual Pressure (L/M)

7 kg N2O/tonne nitric acid ±20%b

Dual Pressure (L/M) with abatement technology

1.5 kg N2O/tonne nitric acid ±10%b

Notes:* Old (pre-1975) plants means that the EF is to be used for the technology that was installed before 1975 and that are still operating.
** Applies to all single pressure plants using all levels of N2O abatement measures (primary, secondary, tertiary and quaternary). Theseabatement measures include all levels of abatement such as process-integrated abatement technologies, tailgas N2O destruction and nonselective catalytic reduction (NSCR, a NOx abatement technology that can also be managed to abate N2O).
Source:aBased on IPCC, 2000; EC, 2007; and the tests from Clean Development Mechanism (CDM) projects presented in US EPA, 2010.

Based on information from EC, 2007; EC, 2009; 2017 Annex I Party GHG Inventory Submissions; Joint Implementation projects andClean Development Mechanism projects availables at the UNFCCC web-site.
b

TIER 3 METHOD
Plant measurements provide the most rigorous data for calculating net emissions (i.e., N2O generation anddestruction factors). Monitoring N2O emissions from nitric acid production is practical because these are point
sources and there are a finite number of production plants. Given currently available technology, instrumentation

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for sampling and monitoring emission rates do not limit precision or accuracy of the overall measurement.
Usually sampling frequency and timing is sufficient to avoid systematic errors and to achieve the desired level ofaccuracy.
As a general rule, it is good practice to conduct sampling and analysis whenever a plant makes any significant
process changes that would affect the generation rate of N2O, and sufficiently often otherwise to ensure that
operating conditions are constant. In addition, plant operators should be consulted annually to determine thespecific destruction technologies employed and confirm their use, since technologies may change over time.
Precise measurement of the emissions rate and abatement efficiencies requires measurement of both the exit
stream and the uncontrolled stream. Where measurement data are available only on the exit stream, goodpractice is to base emissions on these data. In this case, any available estimates of abatement efficiency should
be provided only for information purposes and are not used to calculate emissions.

3.3.2.3

C HOICE OF ACTIVITY DATA

No refinement.

3.3.2.4

C OMPLETENESS

No refinement.

3.3.2.5

D EVELOPING A CONSISTENT TIME SERIESNo refinement.

3.3.3

Uncertainty assessment

No refinement.

3.3.4

Quality Assurance/Quality Control (QA/QC),
Reporting and Documentation

No refinement.

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3.4

ADIPIC ACID PRODUCTION

No refinement.

3.5

CAPROLACTAM, GLYOXAL AND GLYOXYLICACID PRODUCTION

No refinement.

3.6

CARBIDE PRODUCTION

No refinement.

3.7

TITANIUM DIOXIDE PRODUCTION

No refinement.

3.8

SODA ASH PRODUCTION

No refinement.

3.9

PETROCHEMICAL AND CARBON BLACKPRODUCTION

No refinement.

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3.10

FLUOROCHEMICAL PRODUCTION

3.10.1

HFC-23 emission from HCFC-22 production

3.10.1.1 I NTRODUCTION
No refinement.

3.10.1.2 M ETHODOLOGICAL ISSUESCHOICE OF METHOD
There are two broad measurement approaches to estimating HFC-23 emissions from HCFC-22 plants. These aredescribed in IPCC (2000), DEFRA (2002a and 2002b), EFCTC (2003) and UN (2004) and have been translated
into Tier 2 and 3 methodologies described below. National emissions using either of these methodologies are thesum of those from the individual facilities. Tier 1 (default) methodology can be applied to individual plants or, if
there is no abatement by destruction, to the total national output of HCFC-22. Accounting for HFC-23 emissions
is not simply mechanistic but requires information on the process operations responsible for producing andemitting HFC-23, so that the most appropriate methodology and factors can be adopted. Therefore, it is goodpractice, to the extent possible, to establish contacts with plant managers in order to obtain the necessary data.
The Tier 1 method is relatively simple, involving the application of a default emission factor to the quantity of
HCFC-22 produced. This method can be applied at the plant level or the national level. Tier 2 and Tier 3
methodologies are suitable only for plant level calculations because they rely on data that are only available fromplants. In cases where there are Tier 3 data available for some plants, the Tier 1 or Tier 2 methods can be applied
to the remainder to ensure complete coverage.
It is good practice to estimate national emissions by summing measured parameters from all HCFC-22 plants ina country. Tier 3 plant emission measurements are the most accurate, followed by Tier 2 measurements based onplant efficiencies. Direct measurement is significantly more accurate than Tier 1 because it reflects theconditions specific to each manufacturing facility. In most cases, the data necessary to prepare Tier 3 estimatesshould be available because facilities operating to good business practice perform regular or periodic sampling of
the final process vent or within the process itself as part of routine operations. The Tier 1 (default) methodshould be used only in cases where plant-specific data are unavailable and this subcategory is not identified as
significant subcategory under key category. (See Section 4.2 of Volume 1.) Modern plant using processoptimization will need to keep accurate HFC-23 generation data as part of this optimization, so plant-specificdata should be available to most countries in most cases.
The choice of good practice method will depend on national circumstances. The decision tree in Figure 3.16
describes good practice in adapting the methods in these Guidelines to country-specific circumstances.
Procedures to abate emissions include destruction of HFC-23 in a discrete facility and, in this case, emissions
occur only when the destruction facility is not in operation. The tiers of methodology provide estimates for thequantity of HFC-23 that is produced and the share of production that is ultimately emitted depends on the lengthof time that the destruction facility is not operated. For facilities using abatement techniques such as HFC-23
destruction, verification of the abatement efficiency is also done routinely. It is good practice to subtract abated
HFC-23 emissions from national estimates where the abatement has been verified by process records on every
plant.

Tier 1In the Tier 1 methodology, a default factor is used to estimate production (and potential emissions) of HFC-23
from the total HCFC-22 production from each facility (for both potentially dispersive uses, as reported under theMontreal Protocol, and feedstock uses, which are reported separately to the Ozone Secretariat). See Equation
3.30.

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EQUATION 3.30
TIER 1 CALCULATION OF HFC-23 FROM HCFC-22 (PRODUCED) USING DEFAULT FACTOR
E HFC − 23 = EFdefault • PHCFC − 22
Where:
EHFC-23= by-product HFC-23 emissions from HCFC-22 production, kg

EFdefault= HFC-23 default emission factor, kg HFC-23/kg HCFC-22

PHCFC-22= total HCFC-22 production, kg

This methodology is suitable where plant-specific measurements are not available and, in that case, the default
condition is that all of the estimated HFC-23 production is released into the atmosphere.

Tier 2In the Tier 2 methodology, the HFC-23 emission factor is derived from records of process efficiencies and usedin the calculation shown as Equation 3.31. This is a material balance approach and relies on calculating thedifference between the expected production of HCFC-22 and the actual production and then assigning thatdifference to loss of raw materials, loss of product (HCFC-22) and conversion to by-products, including HFC-23.
These parameters will be different for each plant and so should be assessed separately for each facility reporting
into the national data.
EQUATION 3.31
TIER 2 CALCULATION OF HFC-23 FROM HCFC-22 (PRODUCED) USING FACTOR(S) CALCULATEDFROM PROCESS EFFICIENCIESE HFC − 23 = EFcalculated • PHCFC − 22 • Freleased

Where:
EHFC-23= by-product HFC-23 emissions from HCFC-22 production, kg

EFcalculated = HFC-23 calculated emission factor, kg HFC-23/kg HCFC-22
PHCFC-22= total HCFC-22 production, kg

Freleased= Fraction of the year that this stream was released to atmosphere untreated, fraction

The emission factor can be calculated from both the carbon efficiency (Equation 3.32) and the fluorine efficiency(Equation 3.33) and the value used in Equation 3.31 should normally be the average of these two values unlessthere are overriding considerations (such as a much lower uncertainty of one of the efficiency measures) that canbe adequately documented. Annual average carbon and fluorine balance efficiencies are features of a wellmanaged HCFC-22 plant and are either normally available to the plant operator or may be obtained byexamination of process accounting records. Similarly, if there is a vent treatment system, the length of time that
this was in operation, and treating the vent stream from the HCFC-22 plant, should be available from records.
Total HCFC-22 production includes material that is used as a chemical feedstock as well as that which is sold forpotentially dispersive uses.
EQUATION 3.32
CALCULATION OF HFC-23 EMISSION FACTOR FROM CARBON BALANCE EFFICIENCY(100 − CBE ) • F
EFcarbon _ balance =efficiency loss • FCC
100
Where:
EFcarbon_balance = HFC-23 emission factor calculated from carbon balance efficiency, kg HFC-23/kg HCFC-22
CBE= carbon balance efficiency, percent

Fefficiency loss

= factor to assign efficiency loss to HFC-23, fraction

FCC= factor for the carbon content of this component (= 0.81), kg HFC-23/kg HCFC-22

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EQUATION 3.33
CALCULATION OF HFC-23 EMISSION FACTOR FROM FLUORINE BALANCE EFFICIENCY

EFfluorine _ balance=(100 − FBE ) • F
100efficiency loss

• FFC

Where:
EFfluorine_balance = HFC-23 emission factor calculated from fluorine balance efficiency, kg HFC-23/kg
HCFC-22
FBE= fluorine balance efficiency, percent

Fefficiency loss

= factor to assign efficiency loss to HFC-23, fraction

FFC= factor for the fluorine content of this component (= 0.54), kg HFC-23/kg HCFC-22

The factor to assign the efficiency loss to HFC-23 is specific to each plant and, if this method of calculation isused, the factor should have been established by the process operator. By default, the value is 1; that is all of theloss in efficiency is due to co-production of HFC-23. In practice, this is commonly the most significant
efficiency loss, being much larger than losses of raw materials or products.
The factors for carbon and fluorine contents are calculated from the molecular compositions of HFC-23 andHCFC-22 and are common to all HCFC-22 plants at 0.81 for carbon and 0.54 for fluorine.

Tier 3Tier 3 methodologies are potentially the most accurate. The Tier 3 methodologies provided here give equivalent
results and the choice between them will be dictated by the information available in individual facilities. In eachcase, the national emission is the sum of factory specific emissions, each of which may be determined using a
Tier 3 method to estimate the composition and flowrate of gas streams vented to atmosphere (either directly andcontinuously – as in Tier 3a - or by continuous monitoring of a process parameter related to the emission - Tier
3b - or by monitoring the HFC-23 concentration continuously within the reactor product stream - Tier 3c):
EQUATION 3.34
TIER 3A CALCULATION OF HFC-23 EMISSIONS FROM INDIVIDUAL PROCESS STREAMS(DIRECT METHOD)∑∑ ∫ C • f=
E HFC −23

i

ij

j

t

ij

[ ∫t means the quantity should be summed over time.]

Where:
EHFC-23 = total HFC-23 emissions: the sum over all i plants, over all j streams in each plant of the emitted
mass flows f and concentrations C is integrated over time t. (See Equation 3.37 for calculation of‘instantaneous’ HFC-23 emissions in an individual process stream.)or, where an emission factor-based methodology is used:
EQUATION 3.35 (UPDATED)TIER 3B CALCULATION OF HFC-23 EMISSIONS FROM INDIVIDUAL PROCESS STREAMS USING A
SITE- OR PROCESS-SPECIFIC EMISSION FACTOR=
E
HFC −23∑ ∫ C • P [ ∫ means the quantity should be summed over time.]
i

i

t

i

t

Where:
EHFC-23 = total HFC-23 emissions: Ei,j are the emissions from each plant and stream determined using anemission factor. (See Equation 3.38 for calculation of HFC-23 emissions in an individual process
stream.)or, where the HFC-23 concentration within the reactor product stream is used:

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Chapter 3: Chemical Industry Emissions

EQUATION 3.36
TIER 3C CALCULATION OF HFC-23 EMISSIONS FROM INDIVIDUAL PROCESS STREAMS(BY MONITORING REACTOR PRODUCT)=E
HFC −23∑∫C • Piiti

[ ∫t means the quantity should be summed over time.]

Where:
EHFC-23 = total HFC-23 emissions: Pi is the mass flow of HCFC-22 product from the plant reactor at theplant i, and Ci is the concentration of HFC-23 relative to the HCFC-22 product at the plant i.
(See Equation 3.40 for calculation of HFC-23 emissions at an individual facility by in-process
measurement.)

Tier 3a

The Tier 3a method is based on frequent or continuous measurement of the concentration and flow-rate from thevent at an individual plant. So that the quantity emitted to atmosphere is the mathematical product of the massconcentration of the component in the stream, the flowrate of the total stream (in units compatible with the massconcentration) and the length of time that this flow occurred:
EQUATION 3.37
TIER 3A CALCULATION OF ‘INSTANTANEOUS’ HFC-23 EMISSIONS IN AN INDIVIDUAL PROCESSSTREAM (DIRECT METHOD)

Eij = Cij • fij • t
Where:
Eij = ‘instantaneous’ HFC-23 emissions from process stream j at plant i, kg
Cij = the concentration of HFC-23 in the gas stream actually vented from process stream j at plant i,
kg HFC-23/kg gas
fij= the mass flow of the gas stream from process stream j at plant i (generally measured volumetricallyand converted into mass flow using standard process engineering methods), kg gas/hourt= the length of time over which these parameters are measured and remain constant, hours

If any HFC-23 is recovered from the vent stream for use as chemical feedstock, and hence destroyed, it should
be discounted from this emission; material recovered for uses where it may be emitted may be discounted here, if
the emissions are included in the quantity calculated by the methods in Chapter 7. Because emissions aremeasured directly in this tier, it is not necessary to have a separate term for material recovered, unlike Tiers 3band 3c.
The total quantity of HFC-23 released is then the annual sum of these measured instantaneous releases. Periods
when the vent stream is processed in a destruction unit to remove HFC-23 should not be counted in thiscalculation. If it is necessary to estimate the quantity destroyed at each facility, the operator should calculate thisbased on the difference between the operating time of the plant and the duration of release (t above).

Tier 3b

In many cases, measurements are not continuous but were gained during an intensive process survey or plant
trial, and the results of the trial may be used to provide an emission factor for calculating emissions during
normal plant operation. In this case, the emission rate of the by-product is related to a more easily (or accurately)
measurable parameter, such as feedstock flow rate. The trial(s) must meet the following conditions:•

There should have been no major process design, construction or operating changes that affect the plant
upstream of the measurement point and so could render relationships between emissions and production
invalid. (See also Box 3.14)•

The relationship between emissions and plant operating rate must be established during the trial(s), together
with its uncertainty.

For almost all cases the rate of plant operation is a suitable process operating parameter and the quantity of HFC23 emitted depends on the current plant operating rate and the length of time that the vent flow was released.

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EQUATION 3.38 (UPDATED)TIER 3B CALCULATION OF HFC-23 EMISSIONS IN AN INDIVIDUAL PROCESS STREAM USING A
SITE- OR PROCESS-SPECIFIC EMISSION FACTOR

Eij = Sij • Fij • PORij • t − Rij
Where:
Eij= the mass emission of HFC-23 in vent stream j at plant i, kg

Sij= the standard mass emission factor of HFC-23 in vent stream j at plant i per ‘unit’ of a process
operating parameter, such as process operating rate (described in Equation 3.39, below), kg/‘unit’Fij= a dimensionless factor relating the measured standard mass emission rate to the emission rate
at the actual plant operating rate. In many cases, the fraction produced is not sensitive tooperating rate and Fi is unity (i.e., the emission rate is proportional to operating rate). In othercases the emission rate is a more complex function of the operating rate. In all cases Fi should bederived during the plant trial by measuring HFC-23 production at different operating rates. For
situations where a simple function relating the emissions to the operating rate cannot be
determined from testing, the emission factor-based method is not considered appropriate andcontinuous measurement is desirable.

PORij= the current process operating rate applicable to vent stream j at plant i averaged over t in‘unit/hour’. The units of this parameter must be consistent between the plant trial establishing thestandard emission rate and the estimate of ongoing, operational emissions (described in Equation
3.39, below).

t= the actual total duration of venting for the year, or the period if the process is not operated
continuously in hours. Annual emissions become the sum of all the periods during the year. The
periods during which the vent stream is processed in a destruction system should not be counted
here.

Rij

= the quantity of HFC-23 recovered for vent stream j at plant i for use as chemical feedstock, andhence destroyed, kg. Material recovered for uses where it may be emitted potentially may be
counted here if the emissions are included in the quantity calculated by the methods for ODS
substitutes in Chapter 7 of this volume.

EQUATION 3.39 (UPDATED)TIER 3B CALCULATION OF STANDARD EMISSION FOR EMISSION FACTOR-BASED METHODS=
CT ,ij • fT ,ij / PORT ,ij
T ,ij
Where (for each test T):
Sij= the standard mass emission factor of HFC-23 in vent stream j at plant i, kg/‘unit’ (in units
compatible with the factors in Equation 3.38, see PORT,ij below)

CT,ij= the average mass fractional concentration of HFC-23 in vent stream j at plant i during the trial,
kg/kg

f T,ij= the average mass flowrate of vent stream j at plant i during the trial, kg/hour

PORT,ij = the process operating parameter (such as process operating rate) at plant i during the trial,‘unit’/hour. The ‘unit’ depends on the process operating parameter chosen to be representative
for plant i vent stream j (for example, kg/hour or m3/hour of feedstock)

Tier 3c

It is a relatively simple procedure to monitor the concentration of HFC-23 in the product of a reaction system
relative to the amount of HCFC-22. This provides a basis for estimation of the quantity of HFC-23 released as
the mathematical product of the monitored concentration and the mass flow of HCFC-22 made. If there is novent treatment to abate emissions, this is a simple procedure. However, where there is abatement then it must be
shown that this actually treats all streams that may be released into the atmosphere, including direct gas ventsand the outgassing of aqueous streams. The latter, especially, may not be passed to the destruction facility. If all
potential vent streams are not treated, the method cannot be used.

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EQUATION 3.40
TIER 3C CALCULATION OF HFC-23 EMISSIONS FROM AN INDIVIDUAL FACILITY BY IN-PROCESSMEASUREMENT

Ei = Ci • Pj • t F − Ri
Where:
Ei = HFC-23 emissions from an individual facility i, kg
Ci = the concentration of HFC-23 in the reactor product at facility i, kg HFC-23/kg HCFC-22
Pi= the mass of HCFC-22 produced at facility i while this concentration applied, kg

tF= the fractional duration during which this HFC-23 is actually vented to the atmosphere, rather thandestroyed, fraction

Ri = the quantity of HFC-23 recovered from facility i for use as chemical feedstock, and hence
destroyed, kg. Material recovered for uses where it may be emitted potentially may be counted here
if the emissions are included in the quantity calculated by the methods in Chapter 7 of this volume.
The total quantity of HFC-23 released into the atmosphere is the sum of the quantities from the individual
release periods and individual reaction systems. HFC-23 that is recovered for use as chemical feedstock should
be subtracted from the total quantity estimated here.
In summary, the Tier 1 method is relatively simple, involving the application of a default emission factor to thequantity of HCFC-22 produced. This method can be applied at the plant level or the national level. Tier 2 andTier 3 methodologies are suitable only for plant level calculations. In cases where there are Tier 3 data available
for some plants, the Tier 1 or Tier 2 methods can be applied to the remainder to ensure complete coverage.
Uncertainty in the national emission is then calculated using production weighted uncertainties of the individual
sources and standard statistical techniques. Regardless of the method, emissions abated should be subtracted
from the gross estimate from each plant to determine net emissions before these are added together in thenational estimate.

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Figure 3.16

Decision tree for HFC-23 emissions from HCFC-22 production (or other similar
by-product emissions from fluorochemical production)
Start

Are
plant-level
HFC-23 measurement
data available?

Yes

Calculate plant-levelemissions using
plant-level data andTier 3a, 3b or 3c
methodology.

Does any
HFC-23 destruction
take place?

No
Obtain plant-level HFC23 measurement data.
Is theFluorochemical
Production a key category1,
and is this subcategory
significant?

No

Yes

No

Yes

Are
plant-level
HCFC-22 production
data
available?

Are
plant-level
efficiencies
available?

Yes

Estimate emissions byaggregating plant-levelmeasurements, andestimates for plants
without measurements2,
adjusting for HFC-23
destruction.
Box 5: Tier 3
Estimate emissions byaggregating plant-levelmeasurements2, andestimates for plants
without measurements.

Calculate plantlevel emissions
using the Tier 2emission factor.
Is itpossible todocument any
HFC-23destruction?

No

Estimate emissions using the default
emission factor. If the emissions are
estimated at the plant level, aggregate
plant-level emissions.
Box 1: Tier 1

Box 4: Tier 3
Yes

Aggregate plant-levelemissions, adjusting for
HFC-23 destruction.

No
Collect national
HCFC-22
production data.

Yes

Box 3: Tier 2No

Aggregate plant-levelemissions.
Box 2: Tier 2

Note:
1. See Volume 1 Chapter 4, Methodological Choice and Identification of Key Categories (noting Section 4.1.2 on limited resources), for
discussion of key categories and use of decision trees.
2. If there are Tier 3 data available for some plants, the Tier 1 or Tier 2 methods can be applied to the remainder to ensure complete
coverage.

It is good practice to use the Tier 3 method if possible. Direct measurement is significantly more accurate thanTier 1 because it reflects the conditions specific to each manufacturing facility. In most cases, the data necessary
to prepare Tier 3 estimates should be available because facilities operating to good business practice perform
regular or periodic sampling of the final process vent or within the process itself as part of routine operations.
For facilities using abatement techniques such as HFC-23 destruction, verification of the abatement efficiency isalso done routinely. The Tier 1 (default) method should be used only in rare cases where plant-specific data are

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Chapter 3: Chemical Industry Emissions

unavailable and this subcategory is not identified as significant subcategory under key category. (See Section 4.2
of Volume 1.)

CHOICE OF EMISSION FACTORS
There are several measurement options within the Tier 3 method relating to the location and frequency of thesampling. In general, direct measurement of the emissions of HFC-23 may provide the highest accuracy but
continuous or frequent measurement of parameters within the production process area itself may be more
pragmatic and can be equally accurate. In both cases, the frequency of measurement must be high enough torepresent the variability in the process (e.g., across the life of the catalyst). Issues related to measurement
frequency are summarised in Box 3.14, Plant Measurement Frequency. General advice on sampling andrepresentativeness is provided in Volume 1, Chapter 2.
In cases where plant-specific measurements or sampling are not available and Tier 1 methods are used, thedefault emission factor should be used, assuming no abatement methods. For plants in operation prior to 1995
the default emission factor is 0.04 kg HFC-23/kg HCFC-22 (4 percent) (IPCC, 1996; US EPA, 2001; McCulloch,2007). This is a default to be used when there are no measurements and describes the output of HFC-23 from atypical HCFC-22 plant in the absence of recovery or destruction of HFC-23. The value is consistent withatmospheric observations of HFC-23 concentrations in the 1978-1995 time period (Oram et al.,1998). These
showed globally averaged emissions to be equivalent to 2 percent of the total quantity of HCFC-22 produced at atime when significant HFC-23 was being recovered and converted into Halon 1301 (McCulloch, 1992) andabatement was required practice in several countries where there was significant production.
It is possible, by process optimisation, to reduce the production to between 0.015 and 0.03 kg HFC-23/kg
HCFC-22 (1.5 to 3 percent) but it is not possible to completely eliminate HFC-23 formation this way(McCulloch, 2007). Furthermore, the extent of the reduction is highly dependent on the process design and theeconomic environment (measures to reduce HFC-23 can often reduce the process output). In an optimised
process HFC-23 production and emissions will, invariably, have been measured; it is not possible to optimise
process operation without such measurements and so default values have no meaning in this context for anindividual plant. The state of the technological art has been advanced by optimisation of individual plants andthat art should have been built into the design of recent plants, suggesting a default emission factor of 0.03 kg
HFC-23/kg HCFC-22 (3 percent). These default values have a large uncertainty (in the region of 50 percent). For
more accurate assessments, the actual emissions should be determined by Tier 2 or Tier 3 methodology and, if
necessary, assigned to previous years using the guidance provided in Chapter 7 of this volume. Should the ventgas be collected for treatment, thermal oxidation has been shown to reduce HFC-23 emission by 99.996 percent(Irving, 2000).
TABLE 3.28 (UPDATED)
HFC-23 DEFAULT EMISSION FACTORSTechnology
Old, unoptimised plants (e.g., 1940s to 1990/1995)

0.04

Plants of recent design, not specifically optimised

0.03

Global average emissions (1978 - 1995) 1

0.02

For comparison:
Optimised large plant- requiring measurement of HFC-23 (Tier 3)
Plant with effective capture and destruction of HFC-23 (Tier 3)

1

Emission Factor(kg HFC-23/kg HCFC-22 produced)

Down to 0.015
Down to zeroThe global average is calculated from the change in atmospheric concentration of HFC-23. It does not discriminate
between plant emissions, which range from nothing to greater than 4 percent of the HCFC-22 production.

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BOX 3.14
PLANT MEASUREMENT FREQUENCY

The accuracy and precision of the estimates of annual HFC-23 emissions depend on the number ofsamples (the frequency of sample collection) together with the accuracy of measurement offlowrates and the extent to which discrete flow measurements can represent the total quantity
vented. Since production processes are not completely static, the greater the process variability, themore frequently plants need to measure. As a general rule, sampling and analysis should be
repeated whenever a plant makes any significant process changes. Before choosing a sampling
frequency, the plant should set a goal for accuracy and use statistical tools to determine the sample
size necessary to achieve the goal. For example, a study of HCFC-22 producers indicates thatsampling once per day is sufficient to achieve an extremely accurate annual estimate. Thisaccuracy goal should then be revised, if necessary, to take into account the available resources.
(RTI, Cadmus, 1998)

CHOICE OF ACTIVITY DATA
When using the Tier 1 method, production data should be obtained directly from producers. There are several
ways producers may determine their production levels, including shipment weights and measuring volumetimes-density, using flow meters. These data should account for all HCFC-22 production for the year, whether
for sale or for use internally as feedstock, and the plant should describe how the HCFC-22 production rate isdetermined. In some circumstances, producers may consider plant production data to be confidential. For
national-level activity data, submission of HCFC-22 production data is already required under the Montreal
Protocol.

COMPLETENESSIt should be possible to obtain complete sampling data because there are only a small number of HCFC-22 plants
in each country, and it is standard practice for each plant operator to monitor process efficiencies and hence
HFC-23 losses, leading to the adoption of Tier 2 methodology. The destruction efficiencies of thermal oxidisers
used to abate HFC-23 are generally high (>99 percent) but it is important to establish the composition of the exit
gas in order to ensure that account is taken of emissions of fluorinated greenhouse gases from this point.

DEVELOPING A CONSISTENT TIME SERIESEmission of HFC-23 from HCFC-22 production should be estimated using the same method for the entire timeseries and appropriate emission factors. If data for any years in the time series are unavailable for the Tier 3
method, these gaps should be filled according to the guidance provided in Volume 1, Chapter 5.

3.10.1.3 U NCERTAINTY ASSESSMENT
TIER 1
Unlike the other Tiers, where uncertainties are based on measurements and statistics, Tier 1 uncertainties areassessed through expert judgement and an error of approximately 50 percent could be considered for Tier 1
based upon knowledge of the variability in emissions from different manufacturing facilities. An error of thismagnitude will completely outweigh the uncertainty in the activity.

TIER 2
Uncertainty of the Tier 2 result is calculated by the root-squared sum of the individual uncertainties in
production mass quantity and efficiencies, assuming the carbon and fluorine uncertainties are the same. Where
the uncertainties in carbon and fluorine efficiency differ significantly (enough to cause a material difference tothe calculated emission), the value with the lower uncertainty should be used throughout the calculation.
Uncertainty in the value derived by Tier 2 methods is much larger than that expected from Tier 3 but is,nevertheless, quantifiable. Typically, for a plant producing about 4 percent HFC-23, the carbon efficiency is in
the region of 95 percent and the fluorine efficiency 92 percent. If these efficiencies can be measured to within 1
percent, then the error in the Tier 2 HFC-23 estimate would be less than 20 percent. Estimating efficiencies tothis degree of accuracy will require rigorous accounting procedures and that all raw materials and product forsale should be weighed in or out of the facility. Such a regime sets the expected accuracy of the overall activity(for both Tiers 1 and 2); with good accounting and measurement of production by weight, it should be possible
to reduce the error in the activity to below 1 percent.

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TIER 3
For HFC-23, the Tier 3 method is significantly more accurate than either the Tier 2 measured or Tier 1 default
methods. Regular Tier 3 sampling of the vent stream can achieve an accuracy of 1-2 percent at a 95 percent
confidence level in HFC-23 emissions and the uncertainty of the Tier 3 (emission-factor-based) result may besimilar. In both cases, the uncertainty may be calculated statistically from the uncertainties of the input
parameters and, because these methods do not rely on emission factors or activities, the concept of subdividing
uncertainty has no validity.
Uncertainty of the estimate is expressed as a coefficient of variance (percent) and, for each of these streams,
there will be an uncertainty as a consequence of uncertainties in measured concentration and flowrate anduncertainty in the duration of the flow. The combined uncertainty can be determined analytically and should be
calculated using the standard methodology described in Chapter 3 of Volume 1.

3.10.1.4 Q UALITY A SSURANCE /Q UALITY C ONTROL (QA/QC),R EPORTING AND D OCUMENTATIONNo refinement.

3.10.2Emissions from production of fluorinated compounds(other than HFC-23 emissions from HCFC-22
production)

3.10.2.1 I NTRODUCTION
The emission of HFC-23 from HCFC-22 manufacture was considered in Section 3.10.1. Section 3.10.2 (thissection) considers emissions from other fluorochemical production processes. These emissions include emissionsof the intentionally manufactured chemical as well as reactant and by-product emissions. For example, in anational inventory for a fluorochemical plant, significant by-product emissions of SF6, CF4, C2F6, C3F8, C4F10,
C5F12 and C6F14 were reported (United Nations Framework Convention on Climate Change (UNFCCC), 2005).
Other examples include the release of by-product N2O and CF4 from the production of NF3 (Tasaka, 2004; 2007),
CF4 from the production of CFC-11 and 12, or of SF6 from the production of uranium hexafluoride in the nuclear
fuel cycle.
Typically, fluorochemicals may be released from chemical processes involving a broad range of technologies
and processes 2:•

Telomerization Process used in the production of fluorochemicals fluids and polymers;•

Photooxidation of tetrafluoroethylene to make fluorochemical fluids;•

Direct Fluorination often used in SF6 production;•

Halogen Exchange Processes to make HFCs 134a and 245fa and low-boiling-point PFCs like C2F6 and CF4;•

NF3 manufacturing by direct fluorination;•

Production of uranium hexafluoride;•

Production of fluorinated monomers like tetrafluoroethylene and hexafluoropropylene;•

Production of fluorochemical agrochemicals;•

Production of fluorochemical anesthetics;•

Production of perfluorpolyethers;•

Production of hydrofluoroolefins (HFO) such as tetrafluoropropene and its precursors.

2

This list is illustrative.

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Halogen exchange processes are extensively used for HFC manufacture, while most PFCs and SF6 requireelemental fluorine, generated electrochemically. In ‘electrochemical fluorination’ processes, the fluorine is notseparated but makes the desired product in the electrochemical cell. In other processes it is separated andsubsequently used, either as the elemental gas or as a component of a carrier system, such as CoF3. Each process
will have a different spectrum of emissions, in terms of both chemical nature and quantities, and so a common
default emission function is subject to considerable uncertainty.
Potential sources of fluorinated GHG emissions at fluorochemical production facilities include the following:process vents, equipment leaks, and evacuating returned containers. Production-related emissions of fluorinatedGHGs occur from both process vents and equipment leaks. Process vent emissions occur from manufacturing
equipment such as reactors, distillation columns, and packaging equipment. Equipment leak emissions, or
fugitive emissions, occur from valves, flanges, pump seals, compressor seals, pressure relief valves, connectors,
open-ended lines, and sampling connections. In addition, users of fluorinated GHGs may return empty containers(e.g., cylinders) to the production facility for reuse; prior to reuse, the residual fluorinated GHGs (often termed“heels”) may be evacuated from the container and are a potential emission source. In many cases, these "heels"
are contaminated and are exhausted to a treatment device for destruction. In other cases, however, they are
released into the atmosphere. The Tier 1 default emission factor is intended to cover emissions for process vents,
equipment leaks, and container venting.
It is essential that the existence of potentially emissive plants is identified within each country; hence this step isfirst in the decision tree (Figure 3.17). The common factor for most of these plants is the use of anhydroushydrogen fluoride, which is the source of fluorine in halogen exchange processes and in processes that use
elemental fluorine. The production and importation of anhydrous hydrogen fluoride can therefore be used as ameans of tracing significant producers of fluorochemicals. Note that in some cases, the plant consuming theanhydrous hydrogen fluoride may be supplying fluorinated feedstocks to other plants that themselves produce
fluorochemicals and emit GHGs. Further enquiries (see Figure 3.17) can elucidate whether or not there are
significant fluorochemical greenhouse gas emissions at the plant consuming the anhydrous hydrogen fluoride
and whether or not that plant supplies fluorinated feedstocks to other plants.
Feedstocks commonly used in the production of fluoropolymers are HCFC-22, 1,1 difluoroethlyene,tetrafluoroethylene (TFE), and hexafluoropropylene oxide (HFPO). Their production and imports can therefore
be used to identify significant producers of fluoropolymers that may not themselves be consumers of hydrogen
fluoride.
In this section, emissions associated with use are not addressed specifically, being counted in the emissions
related to consumption (see Chapters 4.5, 6, 7 and 8 in this volume).

3.10.2.2 M ETHODOLOGICAL ISSUESCHOICE OF METHOD
It is good practice to choose the method using the decision tree shown in Figure 3.17. If the Category 2B9Fluorochemical Production is identified as key and this subcategory is judged to be significant, inventory
compilers should consider whether or not emissions are dominated by the production of a sub-set of chemicals,
and focus more sophisticated data collection efforts on production of these chemicals. We estimate that 80
fluorochemical production facilities operate among 20 countries world-wide (2004 SRI report; U.S.
Environmental Protection Agency (EPA) Greenhouse Gas Reporting Program (GHGRP)). A survey of national
producers should not be difficult to compile.

Tier 1In the Tier 1 methodology, a default emission factor, or a similar number derived for the particular country's
circumstances, can be used to estimate national production-related emissions of individual HFCs, PFCs, SF6 andother fluorinated greenhouse gases. The default emission factors in Table 3.28a are expressed in terms of kg
emitted/kg produced). When used in a Tier 1 calculation, the applicable default emission factor is multiplied by
the total mass of fluorinated chemical produced.

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EQUATION 3.41
TIER 1 CALCULATION OF PRODUCTION-RELATED EMISSIONS=
Ek EFdefault ,k • Pk
Where:
Ek= production-related emissions of fluorinated greenhouse gas k, kg

EFdefault, k = default emission factor, kg emitted /kg produced
Pk= total production of fluorinated chemical k, kg

The fluorinated greenhouse gas k could be the intended gas being manufactured, an un-intended by-productformed during manufacturing, or a reactant feed. Problems of confidentiality arising from reporting specificcomponent data can be circumvented by providing a single number for total national emissions of each HFC,
PFC, SF6 or other fluorinated GHG. This may be facilitated if data are collected by a third party and reported
only as this total.

Tier 2A mass balance based approach that is based on process efficiencies can be more complicated than for HFC-23
emissions from HCFC-22 plants as there can be a range of by-products responsible for process inefficiency(unlike the case for HCFC-22 where one by-product predominates), as well as loss of the intended product andreactants. However, production efficiency data should exist for each process and, in the absence of a more
rigorous estimate, the emissions can be estimated based on the difference between the total mass of the reactants
and that of the products. These emissions can then be characterized based on information regarding the chemicalcomposition of the emitted mass. The chemical composition may be determined based on measurements,
engineering calculations and assessments, process knowledge, etc. Such an estimate may enable a qualitativedecision as to whether or not these emissions are a significant subcategory under a key category. Should
sufficient measurements of the chemical composition of the emissions exist, this methodology could also be used
for estimating emissions for reporting.
The mass balance method is summarized in Equation 3.41a below. If the chemical composition of the mass ofmaterial emitted from the process is determined through chemical analysis (e.g., a sample taken from thelaboratory-, pilot-, or full-scale process) the Tier 2 estimate is further improved.
EQUATION 3.41A (NEW)
TIER 2 CALCULATION OF PRODUCTION-RELATED EMISSIONS USING A MASS BALANCE APPROACH=
Ek∑∑ ∫ C • M
i

j

t

ijk

ij

Where:
Ek= total production-related emissions (kg) of fluorinated greenhouse gas k: the sum over all i plants,over all j streams in each plant and integrated over time t.

Cijk = the concentration of fluorinated greenhouse gas k present in emissions from stream j, at plant i,
kg/kg
Mij = mass emitted from stream j, at plant i, as determined from a mass balance. This mass determinedfrom the difference in the mass of materials (products, by-products, or reactants) entering andleaving the process, kg
The mass balance method accounts for both vented and leaked emissions, but not emissions from the venting ofreturned cylinders. In the case of cylinder venting, emissions can be estimated based on the mass of material
vented from the cylinder and the chemical composition of the mass.

Tier 3
The Tier 3 methodology is potentially the most accurate estimate and is the sum of factory specific emissions ofeach fluorinated greenhouse gas (reactants, intended product, and by-products) determined using standard
methods to estimate the composition and flowrate of gas streams actually vented to atmosphere after any
abatement technology. Selected examples of standard methods are Fourier transform infrared spectroscopy(FTIR), gas chromatography and mass spectrometry (GC/MS), and calibrated mass flow meters. The particular
standard method used for measurement is chosen based on the type of manufacturing process being monitored.
As noted above, emissions from manufacturing can be divided into two categories: process vents and equipment2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories

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Volume 3: Industrial Processes and Product Useleaks. The total emissions of greenhouse gas k, from both process vents and equipment leaks is determined as
described by Equation 3.41b..

EQUATION 3.41B (NEW)
TIER 3 SUMMATION OF PRODUCTION-RELATED EMISSIONS FROM PROCESS VENTS AND
EQUIPMENT LEAKS=
Ek EkPV + EkEL
Where:
Ek= total production-related emissions of fluorinated greenhouse gas k from process vents andequipment leaks

EkPV= total production-related emissions of fluorinated greenhouse gas k from process vents

EkEL= total production-related emissions of fluorinated greenhouse gas k from equipment leaks

Process vent and equipment leaks are described as follows.

Process Vents
Process vents are typically configured for intermittent or continuous measurement(s) of the concentration, andwhere a process-vent flow rate exists, emissions can be determined as follows:
EQUATION 3.42 (UPDATED)TIER 3 DIRECT CALCULATION OF PRODUCTION-RELATED EMISSIONS FROM PROCESS VENTS=EkPV ∑∑ ∫ Cijk • fijkijt

Where:
EkPV= total process vent, production-related emissions of fluorinated greenhouse gas k: the sum over
all i plants, over all j streams in each plant of the emitted mass flows f and concentrations C andintegrated over time t.

Alternatively, process vent emissions can be determined by utilizing a facility- or process-specific emission
factor. The emission factor is determined by normalizing the emission rate of the reactants, intended product,
and by-products by a more easily (or accurately) measurable parameter, such as feedstock flow rate, as describedin Equation 3.38 in Section 3.10.1:
EQUATION 3.43 (UPDATED)TIER 3 CALCULATION OF PRODUCTION-RELATED EMISSIONS FROM PROCESS VENTS USING A
SITE- OR PROCESS-SPECIFIC EMISSION FACTOR

EkPV =∑∑ ∫ Eijkijt

Where:
EkPV= total process vent, production-related emissions of fluorinated greenhouse gas k: summed over
all i plants, over all j streams and integrated over time t.

Eijk= the process vent emissions of fluorinated greenhouse gas k from each plant and stream
determined by the facility- or process- specific emission factor based methods, described in
Equations 3.38 and 3.39 in Section 3.10.1

For process vents, emissions may be determined based on direct measurements, engineering calculations andassessments, and process knowledge. For continuous processes with significant fluorinated GHG emissions, it isgood practice to develop site-specific or even process-vent-specific emission factors based on measurements ofemissions and activity. For smaller processes and for batch processes, it is good practice to develop the specificemission factors based on either measurements or engineering calculations and assessments. Note that, generally,flows are measured volumetrically and should be converted into mass flow (kg/hour) based on the ideal gas law,
temperature, pressure and composition; similarly concentration should be converted into compatible units (e.g.,
kg/kg).

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In this case, the flowrates, concentrations and duration should be calculated separately for the periods when theabatement technology is or is not operating and only those that lead to actual emissions should be summed andreported.

Cylinder Venting
In the case of cylinder venting, the Tier 3 approach uses the mass of material vented from the cylinder and thechemical composition of the mass as the basis for the emissions estimate. The chemical composition is typicallyavailable from the contents of the cylinder (e.g., stated purity or certificate of analysis). If there is a question
regarding the composition of the cylinder contents (e.g., anticipate that impurities are present), then the Tier 3
approach may include actual measurement of the chemical composition of the vented material using ananalytical method specified previously in this section.

Equipment Leaks
Emissions from equipment leaks can originate from a variety of process and equipment types; there are a numberof different standard methods from which to choose. Three example approaches follow and are based on
guidance from US EPA (1995): the Screening Ranges Approach, Correlation Approach, and Unit-SpecificCorrelation Approach. While these approaches were developed for hydrocarbons primarily, similar equipment isused for fluorochemical production, transfer, and storage and they are therefore appropriate for fluorochemicals.
The choice of equipment component used is mostly based on the physical state of the chemical (gas, liquid) andthe temperature and pressure of the process stream. For a given set of physical parameters, differences in thechemical properties between hydrocarbon and fluorochemicals are not expected to significantly affect the leakrate from valves, flanges, seals, etc. (See section 2.4.1, 2.4.6, and 2.4.7 in EPA, 1995 for additional information
on speciating emissions.) It is, however, important to use appropriate monitoring equipment capable ofmeasuring fluorinated chemicals. For all three approaches, fluorochemicals typically have dramatically different
response factors than hydrocarbons, and in some cases, have little response on analytical equipment commonlyused for hydrocarbon leak detection.
In the Screening Ranges Approach, two sets of emission factors are combined with corresponding equipment
counts to estimate emissions. Emission factors are assigned to pieces of equipment (sources) based on whether aleak detector applied to the source indicates fluorinated GHG concentrations fall above (source greater than, orSG) or below (source less than, or SL) a particular leak concentration definition. These definitions are available
from US EPA (1995) for many types of equipment (these US EPA values are for total organic compounds but
may be applied to fluorinated GHG).

EQUATION 3.43A (NEW)
TIER 3 CALCULATION OF EMISSIONS FROM EQUIPMENT LEAKS USING A SCREENING RANGESAPPROACH

E gijkEL = ( SGig • CGig • C gijk ) + ( SLig • CLig • C gijk )Where:
EgijkEL = the equipment leak–related emissions of fluorinated greenhouse gas k in stream j, from plant i,from equipment type g, kg/hr.
SGig= applicable emission factor for sources with screening values greater than or equal to 10,000
ppmv from equipment type g at plant i, kg/hr-source

CGig = equipment count for sources with screening values greater than or equal to 10,000 ppmv
from equipment type g at plant i.
Cgijk = the concentration of fluorinated greenhouse gas k, present in emissions leaking from equipment
type g, in stream j, from plant i, kg/kg or L/L
SLig = applicable emission factor for sources with screening values less than or equal to 10,000 ppmv
from equipment type g at plant i, kg/hr-source.
CLig = equipment count for sources with screening values less than or equal to 10,000 ppmv fromequipment type g at plant i.
Use of the actual screening value measurements where available (i.e., the actual concentration in ppm, not only
an indication of above or below 10,000 ppmv), with the Correlation Approach is an additional refinement to the
Screening Ranges approach. The Correlation Approach utilizes correlations developed by the US EPA (1995) to2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories

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predict mass emission rate as a function of screening value for a particular equipment type. Equipment types
include gas valves, light liquid valves, connectors, and light liquid pump seals.
EQUATION 3.43B (NEW)
TIER 3 CALCULATION OF EMISSIONS FROM EQUIPMENT LEAKS USING A CORRELATIONAPPROACH

EgijkEL =( Slopeg • ( SVgjk )CEg) • Cgijk )Where:
EgijkEL = the equipment leak–related emissions of fluorinated greenhouse gas k, of stream j, fromequipment type g, at plant i, kg/hr.
Slopeg = slope of correlation equation for equipment type g. See US EPA (1995).
= exponent for correlation equation for equipment type g.

CEg

SVgjk = screening value for greenhouse gas k, in stream j, from equipment type g.
= the concentration of fluorinated greenhouse gas k present in emissions leaking from equipment
type g, in stream j, from plant i, kg/kg

Cgijk

It is important to ensure the units of the correlation and screening values (SV) are consistent with each other. In
the case that the SV value is zero, or the value is higher than the upper limit able to be measured by the portablescreening device, default ELj values in units of kg/hr per equipment type exist.
The third approach for estimating equipment leak emissions is the Unit-Specific Correlation Approach. In the
Unit-Specific Correlation Approach, selected mass emission rates are determined by an equipment bagging
procedure, and the associated screening value (concentration) is concurrently measured. This set of data is used
to develop a unit-specific correlation (i.e., regression equation) between the log base 10 value of the leak/mass
rate and screening value for a specific equipment type on a given process unit, as described in Equation 3.43c.
EQUATION 3.43C (NEW)
TIER 3 CALCULATION OF A UNIT-SPECIFIC CORRELATION

log10 Egijk = ( β 0 + β1 • SVgijk )Where:
EgijkEL = the equipment leak–related emissions of fluorinated greenhouse gas k, in stream j, and equipment
type g, at plant i. kg/hr.
β0= intercept of regression equation (determined from the measurements and data gathered using theequipment bagging procedure for the particular equipment).

β1= slope of regression equation (determined from the measurements and data gathered using theequipment bagging procedure for the particular equipment).

SVgijk = screening value for greenhouse gas k from in stream j, equipment type g, at plant i.
EQUATION 3.43D (NEW)
TIER 3 CALCULATION OF EMISSIONS FROM EQUIPMENT LEAKS USING A UNIT-SPECIFIC
CORRELATION APPROACH

EgijkEL= ( SBCFgijk • 10 β0 • ( SVgijk ) β1 • Cgijk )Where:
EgijkEL= the equipment leak–related emissions of fluorinated greenhouse gas k, in stream j, fromequipment type g, at plant i. kg/hr.

SBCFgijk = Scale bias correction factor (The SBCF is a function of the mean square error of thecorrelation in log space, as described in US EPA (1995).

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Chapter 3: Chemical Industry Emissions

Cgijk= the concentration of fluorinated greenhouse gas k present in emissions leaking from stream j,from plant i. kg/kg

The total emissions of greenhouse gas k, from equipment leaks is determined as described by Equation 3.43e
where emissions are summed over all streams j, equipment types g, at all plants i, over a given time period t.
Should values of Egijk originate from the Unit-Specific Correlation Approach, special care must be used to ensurethat these Egijk are used only for the particular equipment type and plant where they were generated.
EQUATION 3.43E (NEW)
TIER 3 CALCULATION OF PRODUCTION-RELATED EMISSIONS FROM EQUIPMENT LEAKSEkEL =∑∑∑ ∫ EgijkEL
i

j

k

t

Where:
EkEL= total equipment leak, production-related emissions of fluorinated greenhouse gas k andintegrated over time t.

EgijkEL= the equipment leak-related emissions of fluorinated greenhouse gas k in stream j, from plant i,and equipment component type g as determined by the methods, described in Equations 3.43a,
3.43b, or 3.43d.

CHOICE OF EMISSION FACTORS
Tier 1
Tier 1 relies on default emission factors. The default emission factors presented in Table 3.28a are based on asurvey of the available literature and, in the case of the last factor, on an analysis of data reported to the US EPA
Greenhouse Gas Reporting Program. The first two sets of factors apply to production of SF6 and NF3
respectively; the last applies to production of any other fluorochemical. All of the default emission factors
assume there is no use of abatement and the default emission factors for SF6, NF3, and “other fluorochemicals”
include emissions from both process vents and equipment leaks (see Annex 3A.1).
The lower emission factor provided for SF6 was based on estimated typical emission rates during production; thehigher emission factor was found for facilities that also vented residual gas (the “heel”) from containers before
refilling them (because their customers, electronics manufacturers, required highly purified SF6 gas). In countries
with SF6 production, it is good practice to apply the lower emission factor if container heels are known to berecycled or destroyed; otherwise, it is good practice to apply the higher emission factor.
Both the GHGs emitted and the emission rates for those GHGs (kg per kg of the fluorochemical produced) are
shown in the middle column of the table. There is a wide range of substances that may potentially be released
during production of fluorochemicals. In some cases, the fluorinated GHGs released during production of aparticular fluorochemical have GWPs similar to that of the produced fluorochemical (AFEAS 2004). However,in other cases, the GWPs of the released fluorinated GHGs can be significantly different from that of the
produced fluorochemical. The default emission factors presented in Table 3.28a, along with the default
composition of emitted fluorinated GHGs in Table 3.28b, reflect both of these situations.
The Tier 1 factors are highly uncertain. Therefore, if emission factors specific to the facility and produced
fluorochemical are available, these should be used. Because emission rates vary widely among facilities andprocesses, caution should be used when applying emission factors measured for a particular fluorochemical at aparticular facility to the same fluorochemical at a different facility. However, emission factors measured at otherfacilities for the same fluorochemical may be used when the process type (see section 3.10.2.1) used to produce
the fluorochemical is the same at both facilities, when the treatment of container heels is the same at bothfacilities, and when the emission factor does not reflect abatement. (Emission factors that reflect abatement
should not be used in the Tier 1 method.) Note that an emission factor measured for production of one
fluorochemical is not applicable to the production of another, even at the same facility, because different
fluorochemicals (even if they are chemically similar, such as two HFCs) are associated with different byproducts and different by-product generation rates. Thus, not only the identities, but also the quantities of the
GHGs emitted differ.
Some process-specific emission factor data are available from commercially available life cycle assessment
software; these emission factors may be used if their source data, calculation methods, and units of measure are
well documented.

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TABLE 3.28A (NEW)
TIER 1 DEFAULT EMISSION FACTORS FOR FLUOROCHEMICAL PRODUCTION
Fluorochemical Produced

Emission Factor for each Emitted GHG(kg fluorinated GHG emissions/kg
fluorochemical produced)

Uncertainty for default emission factor
for fluorochemical production

SF6

0.03 (SF6)a0.08 (SF6)b±50% (0.015 to 0.045)±50% (0.04 to 0.12)

NF3

0.02 (NF3)c0.03 (N2O)d0.01 (CF4)d±50% (0.01 to 0.03)±50% (0.015 to 0.045)±50% (0.005 to 0.015)

All other fluorochemicals

0.04 (see Table 3.28B for composition ofemitted mass)e-98% to +470% (0.001 to 0.2)f

Source:aO’Connell, 2002.

b

Suizu, 1999.

c

Fthenakis, 2010.

d

Tasaka, 2004; 2007.

As described further in Annex 3A.1 of this Volume, the default emission factor was estimated using data from the US EPA Greenhouse Gas
Reporting Program (US EPA, 2017a; 2017b). Briefly, under the Greenhouse Gas Reporting Program, fluorinated GHG emissions arereported annually on a facility basis and include facilities with and without abatement. Depending on the year, 14 to 16 fluorochemical
production facilities have reported under the Program. Facilities that abate their emissions report their level of abatement for each process asa range. To develop emission factors on an uncontrolled basis, the pre-abatement emissions of each facility were estimated using thearithmetic averages of the abatement ranges reported by that facility for its processes. Then, for each facility, this estimate was divided by the
total quantity of fluorinated gases produced or transformed by that facility to obtain an uncontrolled emission factor for that facility and year.
This was done for all six years for which the US EPA had data at the time the factor was developed. For each facility, the emission factors
for each year were then averaged over the six years of reporting, and the resulting facility averages were averaged to obtain the default factor
above. Because the reporting U.S. facilities use multiple manufacturing methods to produce a wide array of fluorochemicals, 3 averaging thefacility-specific emission factors is expected to provide a default emission factor that is applicable where the manufacturing method is
unknown, as is often the case in a Tier 1 calculation.

ef
As noted above, emission rates from different manufacturing methods can vary widely, a pattern seen in the variation of the emission
factors across the facilities reporting to the U.S. Greenhouse Gas Reporting Program. This variation (summarized here as a 95-percent
confidence interval around the arithmetic mean) provides a first order estimate of the uncertainty of the default Tier 1 emission factor. Thus,
the default emission factor is broadly applicable, but it is also highly uncertain due to the inherent variability of emission rates across
manufacturing methods and produced fluorochemicals.

In addition to the compounds being intentionally produced, a variety of fluorinated GHG by-products can beemitted from fluorochemical manufacturing processes. Emissions of these other fluorinated GHGs can exceed
emissions of the compound being intentionally produced. Where the specific fluorinated GHGs emitted are
known, inventory compilers should assume that the mass emitted consists of these compounds. Where thespecific fluorinated GHGs emitted are not known, it is good practice to assume that the mass emitted consists ofthe fluorinated GHGs listed in Table 3.28b in the proportions provided.
TABLE 3.28B (NEW)
REPRESENTATIVE CHEMICAL COMPOSITION OF THE EMITTED MASS
Fluorinated GHG emitted

Percentage emitted (% of unweighted tonne)a

HFC-134a18

PFC-14 (Perfluoromethane)

18

Perfluorocyclobutane

13

HFC-32

11

HFC-125

11

HFC-2311

3 Fluorochemicals produced in the U.S. and reported to the GHGRP include HFCs, HFEs, PFCs, SF , NF , other fully
63

fluorinated greenhouse gases, and others. Emissions are also reported from the transformation of some of these substances,
as well as CFCs and HCFCs, into other materials such as polymers.

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Chapter 3: Chemical Industry Emissions

TABLE 3.28B (NEW) (CONTINUED)REPRESENTATIVE CHEMICAL COMPOSITION OF THE EMITTED MASS
Fluorinated GHG emitted

Percentage emitted (% of unweighted tonne)a

HFC-143a7

PFC-116 (Perfluoroethane)5

PFC-218 (Perfluoropropane)4

PFC-5-1-14 (Perfluorohexane, FC 72)

3

Due to rounding, the sum of individual items will not equal 100%.
Source:To derive this composition, six years of US EPA GHGRP data were sorted, and the chemical species with the highest estimateduncontrolled emissions (in metric tonne) were identified. The weighted average GWP of these emissions is the same as the weighted average
GWP of the uncontrolled emissions (other than very low-GWP emissions) estimated for fluorinated gas producers that report to the US
EPA. 4 More discussion on the development of the default emissions factor and the representative chemical composition is provided in
Annex 3A.1.

aTier 2 and Tier 3
Tier 2 relies on an estimate of the mass of emissions lost from the process, and if available, measurement(s) of
the chemical composition of the emitted mass. Tier 3 relies on direct measurements of, and the use of, processand facility-specific emission factors to determine the quantities of individual fluorinated GHGs released into theatmosphere.
For Tier 2 and Tier 3, it is important to determine and document whether the production facility abates
production-related emissions of each fluorinated GHG. If the quantity of gas emitted to the atmosphere is
reduced by, for example, thermal treatment of the vent stream, the quantity emitted should be adjusted to accountfor the destruction efficiency of the oxidiser and the length of time that it is in service. As an example, when athermal treatment unit is well-operated and well-maintained, it has been shown to reduce HFC-23 emission by
99.996 percent (Irving, 2000). However, the on-line time of the destruction process can also have a significant
effect on emissions and should be recorded. For example, in the case of a treatment system with 99 percent
removal efficiency, the magnitude of fluorinated GHG emissions would be dominated by the amount of time thegas stream is being treated.
Emission control technologies are used at many facilities to control fluorinated GHG emissions from process
vents. Destruction and removal efficiencies (DREs) are generally based on performance testing of emission
control devices. Results are expected to vary across process equipment and gas flow rates. To apply a DRE to anemission control device, the device must be specifically designed to abate fluorochemicals. If facilities use othertypes of abatement devices not designed specifically for fluorinated GHGs, they should assume that its
destruction efficiency is 0 percent for fluorinated GHGs. In addition, the inventory compiler must demonstrate
through communication with facility managers and subsequent documentation that emissions control
technologies are operated and maintained in accordance with manufacturer specifications. The DRE should only
apply to that portion of emissions that pass through a properly operating and maintained control device, andDRE should not be applied when control device is bypassed, not operating according to manufacturer
specifications, or not maintained in accordance with specifications.

4 To develop both the mass emission factor in Table 3.28a and the break-out of fluorinated GHGs in Table 3.28b, fluorinatedGHGs with GWPs above one were included in the analysis. Fluorinated GHGs with GWPs near one, such as unsaturated
HFCs and PFCs, were excluded. This reduced the emission factor in terms of tons emitted/tons produced, but it had
negligible impact on the metric tonne of CO2eq. emitted/metric tonne produced.

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Figure 3.17 (Updated) Decision Tree for emissions of fluorinated greenhouse gas fromfluorochemical production processes, applicable to product, by-product,
reactant, and fugitive
Start

Compile a list of all
fluorochemical
manufacturers

Are
plant-levelmeasurement
data available?

Yes

Calculate plant-levelemissions using
plant-level data andTier 3 methodology.

Does any
fluorinated GHG
destruction
take place?

No

Are
National activity
data available?

No

Collect national
fluorochemical
activity data.

No

Yes

Estimate emissions byaggregating plant-levelmeasurements, andestimates for plants
without measurements2,
adjusting for fluorinated
GHG destruction.
Box 5: Tier 3

Yes
Is theFluorochemical
Production a key category1,
and is this subcategory
significant?

Yes

Estimate emissions byaggregating plant-levelmeasurements2, andestimates for plants
without measurements.

Collect emissions
data from plants.3

Box 4: Tier 3

Calculate plantlevel emissions
using the Tier 2emission factor.

No

Are
plant-level
efficiencies
available?

Yes

Is it
possible todocument any
fluorinated GHG
destruction?

No
Collect national
fluorochemical
production data.

Estimate emissions fromfluorochemical plants using thedefault emission factor. If theemissions are estimated at the plantlevel, aggregate plant-level emissions.
Box 1: Tier 1No

Yes
Aggregate plant-levelemissions, adjusting for
fluorinated GHG
destruction.
Box 3: Tier 2
Aggregate plant-levelemissions.
Box 2: Tier 2

Note:
1. See Volume 1 Chapter 4, Methodological Choice and Identification of Key Categories (noting 4.1.2 on limited resources), for discussionof key categories and use of decision trees.
2. If there are Tier 3 data available for some plants, the Tier 1 or Tier 2 methods can be applied to the remainder to ensure complete coverage.
3. Data may be collected as a country study by a third party in order to preserve confidentiality.

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Chapter 3: Chemical Industry Emissions

CHOICE OF ACTIVITY DATAFor Tier 1, the activity is the annual mass of the desired fluorochemical that is produced. These activity data
may be available as total production data for the country or may be available for individual facilities. For Tier 2,
the activity is the mass of the produced fluorochemical(s) as well as the consumption of feedstocks. For Tier 3,
the activity data for emissions from process vents may be either the annual mass of the produced
fluorochemical(s) or the annual mass or quantities of one or more feedstocks consumed, and the activity data foremissions from equipment leaks is the number of potentially leaking equipment components of each type.
Individual facilities should have access to the activity data for Tier 2 and Tier 3. For Tier 3, the activity data
may sometimes be available from an industry trade group.

Recycling
Recycling of used gas may be done by the producers of new gas or by other recycling firms. Emissions may
occur during handling and purification of old gas and handling of recycled gas. Specific emission factors are notavailable. Thus, good practice is to use the same default factor as for new production.

COMPLETENESS
Completeness requires that the national GHG inventory include all GHG emissions from all fluorochemical
production processes (including emissions from both process vents and equipment leaks) and any other emission
sources (including container venting) at all facilities in the country. It is important to note that significant GHG
emissions occur not only from processes and facilities producing fluorinated GHGs (for example, HFCs, PFCs,
SF6, NF3, and fluoroethers), but also from processes and facilities producing fluoropolymers, which are often
produced using HCFC, HFC, PFC, and other fluorochemical feedstocks. For some inventory compilers,
identifying smaller producers and, in particular, recycling firms may be a difficult task. However, initial
estimates based on the national mass balance of these fluorinated greenhouse gases should identify if production
related emissions from such entities provide a sizeable contribution to total national emissions.

DEVELOPING A CONSISTENT TIME SERIESBoth by-product and fugitive emissions of fluorocompounds from production processes should be estimatedusing the same method for the entire time series and appropriate emission factors. If data for any years in thetime series are unavailable for the Tier 3 method, these gaps should be filled according to the guidance provided
in Volume 1, Chapter 5.

3.10.2.3 U NCERTAINTY ASSESSMENT
Uncertainty related to use of the Tier 1 default emission factors includes the uncertainty in the activity data andthe assumptions made in estimating the destruction efficiency used in the uncontrolled emissions analysis. For
Tier 1, the uncertainty in activity data needs to be determined for the reporting country and statisticallycombined with the uncertainty in the default emission factor. Typically, in a well operated facility, the default
uncertainty in activity data should be in the region of 1 percent, assuming that rigorous accounting records aremaintained and that production is monitored by weight. There are numerous sources of uncertainty in the default
Tier 1 emission factor. One is the uncertainty associated with the fact that true uncontrolled emission rates
naturally vary from facility to facility depending on the fluorochemicals produced and the processes used tomake them. This variability appears in the US EPA data as differences in the calculated uncontrolled emission
factors across facilities, differences that persist over the entire time series. The year-to-year variability seen in
the calculated uncontrolled emission factor for any one facility is generally much smaller than this facility-tofacility variability. The uncertainty shown in Table 3.28a for the default EF for any other fluorochemicals
reflects this variation among facilities. The 95 percent confidence interval (calculated based on the relative
standard deviation among the facilities’ emission factors) is ±470 percent. Because there cannot be a negativeemission factor on the low side, a value of 0.001 was selected as the lower uncertainty bound, as it isrepresentative of lower emission factor values seen in the data set. This results in an uncertainty range for the
Tier 1 default emission factor of 0.001 to 0.2.
Another source of uncertainty for the default EF for any other fluorochemicals is the exact extent to which theemissions from individual processes are controlled by the facilities reporting to the US EPA GHGRP. As noted
above, the level of abatement (destruction efficiency, or DE) is reported as a range rather than a point estimate,
but a point estimate must be used to back-calculate uncontrolled emissions. Thus, there is uncertainty in the
choice of this point estimate and in the uncontrolled emissions used to calculate emission factors for each facility
and year. In addition, there is uncertainty regarding the exact mix of fluorinated GHGs that would be emitted
from each process without controls. Emissions at the facility level are generally reported by chemical, butemissions at the process level are reported by chemical group. While this provides general process-level
information on the nature and GWP of the emitted GHGs, the GHGs that fall into each group vary in their GWPs.

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However, both of these sources of uncertainty are mitigated by the large number of data points in the analysis,
which come from the large number of processes and significant number of years covered. Thus, the errors related
to the destruction efficiency estimated for each individual process and to the mix of gases emitted tend tobalance out, and the aggregate uncertainty is reduced. A Monte Carlo analysis indicated that the uncertainty foreach facility’s uncontrolled emission factor was less than 50 percent.
For Tier 3 emissions, the uncertainty of the measurements should be determined individually and combined(using standard statistical methods) to provide a total uncertainty for the estimate. The methodology is identicalto that described for HFC-23 from HCFC-22. In the Tier 2 methodology, the uncertainty both of themeasurements of efficiencies and the assignment of losses to individual compounds should be assessed. Because
these are liable to produce a much larger uncertainty than that from Tier 3, the utility of Tier 2 is likely to belimited to assessing whether or not by-product fluorochemical emissions are a significant subcategory under key
category.

3.10.2.4 Q UALITY A SSURANCE /Q UALITY C ONTROL (QA/QC),R EPORTING AND D OCUMENTATIONNo Refinement

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3.11

HYDROGEN PRODUCTION

Hydrogen (H2) is a gas with flammable properties similar to natural gas and gasoline (Hydrogen Council, 2017).
The main current uses of hydrogen are as raw material in refineries and in the production of ammonia, methanol
and other chemicals. Other uses are as an energy carrier in the transport sector, as energy storage and buffer
systems in renewable electricity production, as a main constituent in coal gas (city gas) used for heating andcooking, as well as in semiconductor industry processing and welding. Production of hydrogen may yieldemissions of carbon dioxide (CO2), depending on the production method, while combustion or conversion ofhydrogen to produce heat and electricity yields zero carbon dioxide emissions. An increase in the production,
storage and use of hydrogen is expected in the future, due to an increased demand for low-carbon fuels andtechnologies.

3.11.1Introduction

This section describes methodological guidance for estimating emissions from Hydrogen production. The
methods are primarily applicable to instances where hydrogen is produced as the main product at a stand-alone
facility. Note that where hydrogen is produced as part of a gas mixture (for instance in the case of syngas
production – see Box 3.19), or as a by-product or intermediate product within another chemical or petrochemical
process, then the GHG emissions should be estimated using methods for the most appropriate main product. For
example, hydrogen is commonly produced as a by-product or intermediate product at petroleum refineries and atchemical facilities producing ammonia, methanol, and other products. In these instances, it is good practice forinventory compilers to apply the methodological guidance specific to those processes, as provided elsewhere
within Volume 2 (Energy) and Volume 3 (IPPU), including:•Volume 2, section 4.2 Fugitive emissions from oil and natural gas systems (includes guidance for emissions
from hydrogen production in petroleum refineries, with resultant GHG emissions to be reported under
1.B.2.a.i);•

Volume 3, section 3.2 Ammonia production (with resultant GHG emissions to be reported under 2.B.1);•

Volume 3, section 3.9 Petrochemical and carbon black production (includes guidance for production of
methanol and ethylene, both of which may also generate hydrogen by-product, with resultant GHG
emissions to be reported under the appropriate sub-sector(s) of 2.B.8).

Hydrogen Production Technologies

Hydrogen can be produced through a wide range of chemical, thermochemical and biological processes; Table
3.29 below presents an overview of the current status (in terms of scale of production) and associated GHG
emissions of each known technology.
The predominant hydrogen production technologies, accounting for more than 95 percent of global hydrogenproduction, are steam reforming and gasification of fossil fuels (Ogden, 1999; Speirs et al., 2017). Steamreforming and gasification are thermochemical technologies using feedstock from fossil or renewable sources,
which is combined with heat and catalysts to trigger chemical reactions for transforming the feedstock (forexample, natural gas, LPG, naphtha, coal, methanol, biomass and waste) into a gas mixture rich in hydrogen.
When hydrogen is the final product (see Box 3.15), a series of enhancement and purification steps yields ahighly pure hydrogen output (99.95 percent purity is typical at present).
Production of hydrogen by water electrolysis is widespread, mainly in small-scale plants, and accounts for about
4 percent of current global hydrogen production. Other methods for hydrogen production are currently at a minor
or experimental level. Several of the production methods, e.g. water electrolysis and photo induced water
splitting, do not generate direct GHG emissions from the hydrogen production process. Others, e.g. steam
reforming of ammonia and thermal water splitting, generate no process emissions of GHGs but do emit GHGs
from stationary combustion of fuels to heat the production process, and accordingly these emissions should bereported in the Energy sector.
Biological methods to generate hydrogen are currently at a very small-scale, and typically involve a fermentation
process to produce hydrogen, using living microbes such as algae and bacteria. In the production process either
fossil or biogenic materials are consumed under anaerobic conditions, and the output products are hydrogen gas
containing minor amounts of CO2, CH4 and other organic substances, and CO2 off-gas which may be partly
captured by the microbes; at present a maximum of 2 percent CH4 by mass in the hydrogen product is reported
in some anaerobic biological methods (Braga et al 2017). Any CH4 and CO2 produced in the process will
become a constituent part of the fermentation gas product, and any subsequent emissions from this gas use

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Volume 3: Industrial Processes and Product Useshould be reported in the sector(s) where it is used. Hence, emissions from hydrogen production by biologicalmethods are considered negligible and should not be reported in the hydrogen production sector.
Further development and increased uptake of low-emission hydrogen production methods is anticipated,
however, methods using fossil feedstock currently dominate due to economic reasons (Speirs et al., 2017).

Hydrogen Production: GHG Emission Sources and Reporting Allocations

There are many different hydrogen production technologies, and their contribution to GHG emissions range fromzero direct emissions at the production facility (e.g. water electrolysis) to significant direct GHG emissions (e.g.
from steam reforming or gasification of fossil feedstocks). Of the directly emissive technologies, some utilise
fossil fuels only for combustion, to heat the process, with no chemical process GHG emissions associated withthe hydrogen production, such as dehydrogenation or thermal water splitting, whilst hydrogen production
through steam reforming or gasification of fossil materials does result in both chemical process and combustionderived GHG emissions.
Table 3.29 provides information on best practice for the reporting allocation of emissions from each technology,
and further guidance is as follows:(i)

The GHG emissions from hydrogen production as a pure main product at a stand-alone facility should bereported under the Hydrogen production sector in IPPU. This typically includes GHG emissions fromhydrogen production technologies that generate process emissions from fossil feedstocks, i.e. steam
reforming or gasification of fossil materials. Hydrogen production methods that generate no direct GHG
emissions, such as the electrolysis of water, should not be considered in the IPPU sector;(ii) It is good practice to report under Hydrogen Production all the GHG emissions from steam reforming andgasification of fossil materials, including the fuel combustion and chemical process emissions from thefuels and feedstock, and to exclude these fuel combustion emissions from the Energy sector, in line with the
IPCC methods for other similar chemical processes, such as production of ammonia (2B1) andpetrochemicals (2B8).
(iii) Emissions of CO2 from thermochemical processes such as steam reforming and gasification using biomass
as feedstock should be reported as a memo item only, to avoid double counting with emissions reported insource categories in Agriculture, Forestry and Other Land Use (AFOLU). If the feedstock contains bothfossil and biogenic components (e.g., auto diesel mixed in with biodiesel, waste, etc.), the CO2 emission
should be allocated partly to the Hydrogen production sector and partly to the memo item, relative to therespective fossil and biogenic carbon shares.
(iv) As noted above, where hydrogen is produced as a by-product for sale or as an intermediate product in asource category provided with methodological guidance on GHG emissions from hydrogen production, it isgood practice to estimate GHG emissions by applying the methodological guidance for the appropriate
source category. These source categories include:a.

Petroleum refineries (Volume 2, section 4.2)b.

Ammonia production (Volume 3, section 3.2)c.

Methanol production and ethylene production (Volume 3, section 3.9)(v) Where GHG emissions arise from production of intermediate or by-product hydrogen (including gas
mixtures containing hydrogen) in sectors not provided with a methodology for estimating these emissions,
it is good practice to use one of the methodological approaches provided in Volume 3 IPPU (ammonia,
methanol or hydrogen), as follows:a.

If the feedstock is completely oxidized and the main product does not contain carbon, themethodology for hydrogen production should be used.

b.

If the feedstock is partly oxidized and the main product does not contain carbon, the methodology
for ammonia production should be used.

c.

If the main product contains carbon, the methodology for methanol production and ethylene
production should be used.

The compiler should use the methodology that minimises uncertainties in the national inventory, transparently
note which method(s) are used, and report the GHG emissions in the appropriate source category of the main
product for that facility.
(vi) Where hydrogen is produced as part of a hydrogen carrier, or released from such a hydrogen carrier system,
the GHG emissions yielded from the process may be allocated to a range of different sectors, according to
the carrier type. See Box 3.17 for further details.

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Chapter 3: Chemical Industry Emissions(vii) Where activity data for hydrogen production at the national level may combine data from stand-alone
facilities and integrated facilities within other sectors, and from emissive and non-emissive technologies,
inventory compilers should take care to ensure that gaps and double counting of emissions do not occur.
In light of the range of production technologies, it may be difficult for inventory compilers to obtain fullyresolved activity data by technology, making it difficult to estimate and report GHG emissions consistent withthe good practice methods outlined above.
As for all inventory source categories, it is good practice to estimate and report emissions from hydrogenproduction such that inventory uncertainties are minimised, and to minimise the risk of any gaps or doublecounts in the reported estimates across Energy and IPPU source categories. In the event that the good practice
approach to reporting hydrogen production cannot be achieved due to national circumstances, then inventory
compilers should transparently document the methods applied, note where emissions from hydrogen production
are included (fully or in part) within Energy and/or other IPPU source categories, and derive uncertainty
estimates that reflect the country-specific approach.
See Box 3.16 for details about double counting.

Reporting of GHGs contained within the hydrogen productSome hydrogen production methods generate GHGs as an unintended constituent of the product. For instance,hydrogen produced by biological processes may contain minor amounts of methane. In these cases, the GHGs
are emitted after the product has been sold to an end user, either from the use or fugitive release of the productitself or from the combustion of it. It is good practice to estimate GHG emissions using methods specific to thefinal emission source, and report the emissions in that sector, and not in the Hydrogen production sector.

Carbon Dioxide Capture and Storage

Should CO2 capture technology be installed and used at a plant where hydrogen is produced from steam
reforming or gasification of fossil materials, it is good practice to deduct the CO2 captured in a higher tieremissions calculation. The default assumption is that there is no CO2 capture and storage (CCS). In most cases,
methodologies that account for CO2 capture should consider that CO2 emissions captured in the process may beboth combustion and process-related. However, in the case of hydrogen production from steam reforming or
gasification of fossil materials, no distinction is made between fuel and feedstock emissions with all emissions
accounted for in the IPPU Sector. Similarly, all CO2 captured should be accounted for in the IPPU Sector. For
additional information on CO2 capture and storage, refer to Volume 3, Section 1.2.2 and for more details on
capture and storage to Volume 2, Section 2.3.4.

CH 4 and N 2 O emissions from hydrogen production

Steam reforming and gasification produce very minor emissions of CH4 and N2O, in addition to CO2 emissions.
The available literature indicates that emissions of CH4 and N2O are very low, activity data for the process
combustion source are likely to be hard to obtain, and the literature evidence is insufficient to establish an
estimation method. Hence, no reporting of CH4 and N2O is required in this sector.

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BOX 3.15 (NEW)DEFINITIONSPure hydrogen and gas mixtures
Pure hydrogen is hydrogen gas that has been purified to meet industry product quality standards.
Pure hydrogen is produced by complete oxidation of feedstocks or by other technologies (Table
3.29).
Hydrogen that is produced by technologies that partially oxidize a hydrocarbon feedstock will also
contain other gases (typically CH4, CO, CO2, other hydrocarbons) and is defined as a "gasmixture".
Final products and intermediate products
A final product is an intended output product from a production facility. The final product can beeither sold as a commercial product or exported offsite for use in another facility. An intermediate
product is an output from one production process, which is consumed as raw material or fuel in alater production step at the same facility.
Main products and by-products
A main product is the product defining a facility’s sector in the IPCC reporting. As a rule ofthumb, the main product is the product generating the highest monetary production value. Byproducts are all other products made intentionally at the facility. If nothing else is stated, main
products and by-products are final products.
Feedstock, raw material and fuelIn this section, feedstock means the total input material in a manufacturing process. Raw material
is the part of the feedstock being transformed into the final or intermediate product(s). Fuel is amaterial combusted to produce heat. The fuel might be derived from the feedstock (i.e. internalenergy source) or provided separately (i.e. external energy source).

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Chapter 3: Chemical Industry Emissions

TABLE 3.29 (NEW)
CURRENT HYDROGEN PRODUCTION METHODS – STATUS OF DEVELOPMENT AND ALLOCATION OF EMISSIONS TO SECTOR
Category

Technology

Feedstock

Pure main
producthydrogenSteamreforming

FossilStatus ofdevelopment1
Major

BiofuelGasification

Water
electrolysis
Dehydrogenation

Byproduct orintermedia
te producthydrogen2

Sector

Allocation principle
Fossil process emissions

Minor

Hydrogenproduction2
Memo

Waste

Minor andincreasing

Hydrogenproduction2 /Memo

MethanolFossilMinor andmature
Major

Biomass

Minor

Hydrogenproduction2
Hydrogenproduction2
Memo

Waste

Minor andincreasing
Moderate andincreasing
Minor

Water
Organic
Hydride6
Ammonia

Minor

Biogenic process
emissions
Fossil/biogenic3 process
emissions
Fossil process emissions
Fossil process emissions

Hydrogenproduction2 /MemoNot applicable

Biogenic process
emissions
Fossil/biogenic3 process
emissions
No direct emissions5

Energy (stationary
combustion)
Energy (stationary
combustion)
Not applicable

Only combustion
emissions
Only combustion
emissions4
No direct emissions5

Energy (stationary
combustion)
Energy (stationary
combustion)

Only combustion
emissions4
Only combustion
emissions4

Fermentation

Biomass

Experimental

Methanecracking
Thermalwater
splittingPhotocatalytic
splitting
Photo
biologicalsplittingRefining of
crude
petroleumAmmonia
production

Natural gas

Minor

Water

Experimental

Water

Experimental

Not applicable

No direct emissions5

Water

Experimental

Not applicable

No direct emissions5

All

Major

Energy (fugitive)

All

Major

Ammonia
production

Methanolproduction

All

Major

Petrochemical andCarbon Black

Ethylene
production

All

Minor

Petrochemical andCarbon Black

Steelproduction

All

Minor

Iron and Steel andMetallurgical Coke

Caustic soda
production

Sodiumchloride

Moderate

Not applicable

Fuel cellreforming

MethanolExperimental

FossilMinor andincreasing

Sector of the end
user
Sector of the end
user

Hydrogen produced as
by-product orintermediate productHydrogen produced as
by-product orintermediate productHydrogen produced as
by-product orintermediate productHydrogen produced as
by-product orintermediate productHydrogen produced as
by-product orintermediate productProduced byelectrolysis. No directemissions5
Hydrogen produced as
an intermediate productHydrogen produced as
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TABLE 3.29 (NEW) (CONTINUED)CURRENT HYDROGEN PRODUCTION METHODS – STATUS OF DEVELOPMENT AND ALLOCATION OF
EMISSIONS TO SECTOR
Notes:
1
Status of development refers to the current situation in a global scale. Major, moderate and minor reflect the amount of industrialhydrogen production. Experimental means that the hydrogen is not yet produced in an industrial scale.
2
Where hydrogen is produced as a by-product or intermediate product, the emissions are typically already accounted for in theemission estimates for the respective sectors derived using methodological guidance in Volume 3 Energy or Volume 4 IPPU.
Emissions from production of hydrogen as part of mixtures with other gases, e.g., syngas, are not covered by this section. See Box
3.15 for the definition of main product, by-product and intermediate product and Box 3.16 about double counting.
3
Non-biogenic emissions are reported to IPPU and biogenic emissions are reported as a memo item (i.e. not included in the IPPU
totals).
4
No process emissions, as the feedstock does not contain carbon. All emissions arise from combustion of fuels to power the
production process.
5
Only direct emissions (i.e. emissions generated in the production facilities during production) are considered, according to standard
IPPU methodology.
6
In dehydrogenation, the raw material is not consumed. Hence, all emissions come from fuel combusted to produce heat for thereaction.

BOX 3.16 (NEW)DOUBLE COUNTING, COMPLETENESS AND CROSS-CUTTING ALLOCATION• In order to avoid double counting, activity data and emissions from production of hydrogen
reported in the Hydrogen production sector must be excluded from other sectors, i.e. the total
quantities of oil, gas, coal and other fossil materials (fuel plus feedstock) used in hydrogenproduction must be subtracted from the quantity reported under energy use in the Energy sector.
Conversely, activity data and emissions from production of hydrogen reported in the Energy
sector and IPPU sectors other than Hydrogen production must be excluded from the Hydrogenproduction sector.
• Where the level of activity data resolution does not enable separation of the production ofhydrogen as a pure product, by-product or gas mixture, then it is good practice for compilers to
calculate and report emission estimates such that (i) the emission estimates are complete with nodouble-counting, and (ii) that overall inventory uncertainty is minimised. Further, it is goodpractice to clearly explain the national circumstances, activity data, methods and reporting
allocations in inventory submissions.
• In many hydrogen production processes, the same fossil material is used both as raw material forthe production process and as fuel combusted to heat the process. It is impractical to seek todistinguish between “fuel” and “feedstock” and to report these emissions separately. Therefore, it
is good practice to report both the fuel combustion and chemical process emissions in the
Hydrogen production sector, and to exclude these fuel combustion emissions from the Energy
sector, consistent with the IPPU cross-cutting guidance as presented in Vol. 3 IPPU, Chapter 1.2.1
and Box 1.1.
• To minimise the risk of gaps and double-counts, inventory compilers may need to consult withstatistical agencies, trade associations and plant operators as appropriate, to seek to ensure that thehydrogen production activity data does not include any hydrogen derived from non-emissive
technologies, nor any production of hydrogen as a by-product or intermediate within facilities that
produce other main outputs such as refineries, ammonia and methanol plant where the GHG
emissions are already accounted for elsewhere in the inventory.
• Recovered CO2 might be delivered for downstream use, for instance as raw material in othermanufacturing processes or as dry ice (cooling, cleaning, etc.), or sent to a permanent storage.
When used in a downstream manufacturing sector, the CO2 might be embedded into a product (forinstance through a chemical reaction) or emitted to the atmosphere. It is good practice to report theemission of CO2 from downstream use in the downstream IPPU or other sector, and to subtract
the recovered CO2 from the Hydrogen production sector.
• The downstream use and permanent storage of recovered CO2 should be transparently described
and must be documented in accordance with IPCC Guidelines. It is good practice to cross-checkthat all emissions from downstream use of recovered CO2 is accounted for in the corresponding
downstream sector(s).

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BOX 3.17 (NEW)PRODUCTION AND USE OF HYDROGEN CARRIERS

Hydrogen is a highly volatile gas, which may be transported through a pipeline or in tanks as acompressed gas or as a cryogenic liquid. To facilitate the safe, efficient transport and storage ofhydrogen, a carrier chemical may be used. A ‘hydrogen carrier’ is a chemical substance containinghydrogen that is easy to store and transport, from which the hydrogen gas can be extracted througha chemical reaction for use in a downstream sector. Some carriers are recycled for subsequenthydrogen deliveries, while others are consumed in the process where the hydrogen is released.
Some hydrogen carriers are produced with a full load of hydrogen in a single-step process. Other
hydrogen carriers are produced and loaded with hydrogen in a two-step process, first as an“empty” carrier. Subsequently, the hydrogen (normally produced at a different plant) is embedded
into the empty carrier through a chemical reaction.
The hydrogen carrier is transported to a downstream facility, for example a refuelling station,
where the hydrogen is released by a chemical reaction (dehydrogenation) and filled into a vehicle
or machine, or the hydrogen carrier itself is filled into a fuel cell, in which the hydrogen (H2) isreleased and consumed.
The different types of hydrogen carrier chemicals have the GHG emissions from their production
and use allocated to different sectors.
Organic hydrides
Hydrogen can be reacted with aromatic substances such as benzene and toluene to form liquidorganic hydrides.
The emissions from the manufacturing of hydrogen should be allocated to the Hydrogenproduction sector, while the emissions from production of the aromatic substances used as “empty
carriers” should be allocated to the Petrochemical and carbon black sector.
The reaction releasing hydrogen at the downstream facility produces no process emissions of
GHGs. Instead, the organic hydride is converted back to the original aromatic substance andtransported to the hydrogen production facility to embed more hydrogen, in a circular material
flow pattern. The hydrogen-releasing reaction requires heat, which might be produced by
combustion of fossil fuels. In such cases, the emitted CO2 should be allocated to the Energy sector(stationary combustion).
Ammonia
Ammonia (NH3) is a hydrogen-rich gas that can be cooled down and/or compressed into a liquid
and transported to a downstream facility or fuel cell. There the hydrogen (H2) may be released by achemical reaction (dehydrogenation).
The emissions from the ammonia production process should be allocated to the Ammonia
production sector, even though the purpose of producing the ammonia is to derive hydrogen fordownstream use.
For the use of ammonia as hydrogen carrier, no emissions should be allocated to the Hydrogenproduction sector. The reaction releasing hydrogen at a downstream facility produces no process
emissions of CO2, since the ammonia contains no carbon. Fossil combustion emissions from thehydrogen releasing reaction should be allocated to the Energy sector (stationary combustion).
Methanol
Methanol (CH3OH) is a hydrogen-rich liquid that can be transported to a downstream facility,
where the hydrogen may be released by a chemical reaction (e.g. steam reforming).
The emissions from the methanol production should be allocated to the Petrochemical and carbon
black production sector, even though the purpose of producing the methanol is to derive hydrogenfor downstream use.
The process at the downstream facility to release hydrogen from the methanol generates process
emissions of CO2. These emissions should be reported in the Hydrogen production sector, using
the estimation methods provided for this sector.
Consumption of methanol in direct methanol fuel cells yields CO2 emissions, but hydrogen (H2)
isn’t involved in the reactions. Accordingly, these CO2 emissions should be reported in the Energy
sector.

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3.11.2

Methodological issues

The predominant methods for hydrogen production at present are steam reforming and gasification of fossil
feedstocks. Both technologies oxidise the feedstock during the process itself and also in combustion to heat theprocess, releasing CO2.
Technologies for producing hydrogen from fossil or biogenic feedstocks in an open, aerobic environment can beplaced in either of two categories, according to the degree of conversion of the feedstock carbon: complete
oxidation technologies and partial oxidation technologies.
Complete oxidation technologies convert all feedstock carbon into CO2 (except for a small residue of solidcarbon), and they have hydrogen as the main product. The CO2 emissions can be estimated from feedstock
consumption or hydrogen production data.
Partial oxidation technologies convert parts of feedstock carbon into CO2, and they result in gas mixtures
having hydrogen as a constituent. In several industries using hydrogen as a raw material, partial oxidation
technologies 5 are often used to produce an intermediate mixture of hydrogen and CO (e.g. syngas production,
see Box 3.19), as also CO is needed for raw material. To regulate the H2:CO ratio, hydrogen might be separated
from the mixture as a by-product and burnt for fuel or used externally (e.g. sold for use in a downstream sector).
A list of production methods and allocation by sector is given in Table 3.29.

COMPLETE OXIDATION TECHNOLOGIESThe main complete oxidation technologies are steam reforming of natural gas and fossil liquids (Figure 3.18) andgasification of coal and lignite (Figure 3.19). Both production processes have several steps, in order to maximise
the hydrogen output. The first one partially oxidizes the feedstock carbon and generates a gas mixture containinghydrogen, carbon monoxide and, in the case of gasification of coal and lignite, solid carbon. The next stepfurther oxidizes the carbon by a water gas shift reaction, yielding even more hydrogen. An integrated
combustion reaction using feedstock (or gasified feedstock) as fuel, or in some cases a support fuel, provides
energy to produce steam for the water gas shift reaction.
Other feedstocks are sometimes used as well, though in a very small scale at present. The feedstock material may
be fossil carbon in origin, biogenic carbon in origin, or a mixture of fossil and biogenic (such as the use of mixed
wastes as a feedstock), but the underlying chemistry to derive the hydrogen is the same and hence the GHG
emission estimation methods are similar.
In both the hydrogen producing (overall) reaction and the combustion reaction there is a close to 1:1 molar
relation between the produced CO2 and the carbon contained in the feedstock. The only exception is a small
amount of solid carbon residue disposed of as waste.
Figure 3.18 (New)Hydrogen production via steam reforming with water gas shift reaction

ZnS
Naturalgas

CO+H2O
Reforming

Cleaning
ZnO

SyngasHydrogen

H2+CO2

Water Gas
Shift

CarbonCapturePurification

CO2

Steam
Heat
RecoveryWater

5 Partial oxidation technologies include all technologies partially oxidizing the feedstock. One of these is commonly called“partial oxidation”.

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Figure 3.19 (New)Hydrogen production via gasification with water gas shift reaction 1

Air

Air
Separation

Steam

Nitrogen

OxygenGasification

CO+H2O
H2

H2+CO2

Water Gas
Shift

Gas
Cleaning

Pre-treated coal/
Biomass

H2
Separation

HydrogenNote:
1

The flue gas from the H2 separation step, containing CO and methane, is combusted in a boiler to produce heat (i.e. steam).

Source:Matzen et al., 2015; The National Energy Technology Laboratory, 2017.

BOX 3.18 (NEW)CHEMICAL REACTIONS IN HYDROGEN PRODUCTION BY COMPLETE OXIDATION TECHNOLOGIESSteam reforming of natural gas (overall reactions):
1a) Reforming: CH4 + 2H2O → CO2 + 4H21b) Combustion: CH4 + 2O2 → CO2 + 2H2O
Steam reforming or gasification of other fossil or biogenic feedstocks (overall general formulas):2a) Reforming or gasification: CaHbOc + (2a-c)*H2O → a*CO2 + (2a+0.5b-c)*H22b) Combustion: CaHbOc + (a+0.25b-0.5c)*O2 → a*CO2 + 0.5b*H2O
Gasification of waste (overall general formulas):3a) Gasification:
CaHbOcNdSe + (2a-c+2d+2e)*H2O → a*CO2 + d*NO2 + e*SO2 + (2a+0.5b- c+2d+2e)*H2
3b) Combustion:
CaHbOcNdSe + (a+0.25b-0.5c+d+e)*O2 → a*CO2 + d*NO2 + e*SO2 + 0.5b*H2O
In all these overall reactions the ratio of consumed feedstock carbon atoms to produced CO2
molecules is 1:1. The molar relation between each reforming or gasification reaction and thesubsequent combustion reaction depends on the efficiency of the production process, and the ratio
of produced hydrogen to produced CO2 varies accordingly (Braga et al., 2017; Trane et al., 2012).

PARTIAL OXIDATION TECHNOLOGIESPartial oxidation technologies are reforming and gasification technologies producing hydrogen and carbon
monoxide (CO) in closed systems with a sub-stoichiometric supply of oxygen. The process typically includes thefirst reaction step in a complete oxidation technology producing a mixture of hydrogen and CO, and it might
include one or more subsequent steps (e.g., a water gas shift reaction) to obtain the desired ratios for the twogases. Purified gases, including H2, may be produced as a by-product.
Emissions from technologies partially oxidizing the feedstock, including syngas production (see Box 3.19
below), are not covered by the estimation methods in this section, to avoid double counting with other sectors.

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BOX 3.19 (NEW)SYNGAS

Syngas is a gas mixture containing hydrogen, carbon monoxide and sometimes smaller amounts of
CO2, methane and other gases as well. The hydrogen to carbon monoxide molar ratio varies fromabout 0.5 to 5 depending on the feedstock. Syngas is produced by different technologies partially
oxidizing the feedstock, including steam reforming, gasification, partial oxidation and auto-thermal
reforming, in the presence of heat. The feedstock may be natural gas, coal, liquid refinery residues
or other carbon containing materials.
Syngas is typically used as an intermediate product in refineries, ammonia, methanol or otherchemical industries, but production for offsite use as an energy product or separated into its single
gases also occurs. Surplus hydrogen might be separated from the syngas and purified into a byproduct to obtain a specific H:CO ratio in the syngas for use in the production process of the main
product. Emissions from syngas production are not covered by the estimation methods in thissection. Methods to estimate GHG emissions from syngas intermediate and hydrogen by-productproduction in petroleum refineries, ammonia, methanol and other chemical production areprovided in the respective Energy and IPPU sectors.
Source:Abbas, 2018; Copeland et al., 2005; Maurstad, 2005; The Global Syngas Technologies Council, 2018; The
National Energy Technology Laboratory, 2018, 2002.

OTHER PRODUCTION METHODS
Biological methods including fermentation produce hydrogen by using living microbes like algae and bacteria.
In the production process either fossil or biogenic raw materials are consumed under anaerobic conditions, andthe output products are hydrogen containing minor amounts of CO2, methane and other organic substances, andCO2 off-gas. Methane and other GHGs being produced along with the hydrogen are parts of the product andshould be reported in the sector(s) where it is used. The CO2 off-gas is assumed balanced by the CO2 taken up by
the microbes, and should not be reported.
Production of hydrogen by other technologies than those mentioned above, including water electrolysis, photo
induced water splitting, steam reforming of ammonia and thermal water splitting, are typically without process
GHG emissions, and emissions from these production methods should not be reported in the Hydrogenproduction sector.

3.11.2.1 C HOICE OF METHOD
The choice of method will depend on the availability of activity data, as shown in the decision tree (Figure 3.20).
The Tier 1c, 2c and 3c methods are based on feedstock consumption data, while the Tier 1b, 2b and 3b methods
are based on hydrogen production data. The Tier 1a method is based on hydrogen production data on a total
national or regional level, or hydrogen production capacity if production data are not available. There is no Tiermethod labelled 2a or 3a on this section.
If all relevant activity data are available, it is good practice to choose the method having the lowest overall
uncertainty. A higher Tier method has a lower uncertainty than a lower one, and the Tier c method normally has
a lower uncertainty than the Tier b method at the same Tier level. The Tier 1a method has the highest uncertainty.
CO2 released from hydrogen production may be recovered, either for capture and storage or for use in otherdownstream manufacturing industries. In all emission estimation methods, it is good practice to subtract
recovered CO2 from the estimated emissions in the Hydrogen production sector and to include the emissions in
the respective downstream IPPU sector(s). If the recovered CO2 is sent to permanent storage, it is good practiceto subtract the recovered CO2 from the Hydrogen production sector.
The estimation methods below are presented using energy units (GJ) for feedstock activity data, and mass units(tonne) for the hydrogen production data. Where these parameters are reported in different units at the nationalor facility level (e.g. volume, mass) then unit conversions consistent with national or facility data or IPCC
defaults may be applied.
Guidance on how to allocate the GHG emissions to the correct sector is given in the previous section (3.11.1).

TIER 1 METHODThe Tier 1 methods use national or regional level activity data together with default factors and data on
recovered CO2 to derive emissions. This method should be used if country-specific factors (Tier 2) or plant

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Chapter 3: Chemical Industry Emissions

specific activity data and factors (Tier 3) are not available and hydrogen production is not a key category. The
activity data are consumption of feedstock (Tier 1c) or production of hydrogen (Tier 1b and 1a). In the Tier 1cand 1b methods the activity data are split by type of feedstock, and feedstock specific factors in Table 3.30
should be used. In the Tier 1a method total national or regional activity data and the general default factors in
Table 3.30 could be used.
The CO2 emissions are estimated as follows:
EQUATION 3.44 (NEW)CO2 EMISSIONS FROM HYDROGEN PRODUCTION – TIER 1C

Eco2=∑ ( FC • CCF • 44 12) − R
j

j

j

co2

EQUATION 3.45 (NEW)CO2 EMISSIONS FROM HYDROGEN PRODUCTION – TIER 1B

Eco2=∑ ( HP • FRF • CCF • 44 12) − R
j

j

j

j

co2

EQUATION 3.46 (NEW)CO2 EMISSIONS FROM HYDROGEN PRODUCTION – TIER 1A

Eco2 =HP • FRF • CCF • 44

12

− Rco2

Where:
ECO2= emissions of CO2, tonneFC= feedstock consumption in production of pure hydrogen as main product, GJ

HP= pure hydrogen produced as main product, tonne

FRF= feedstock requirement per unit of output, GJ feedstock / tonne hydrogen produced

CCF= carbon content factor, tonne C / GJ feedstockj (subscript) = feedstock j
RCO2= CO2 recovered, tonne

Aggregate feedstock consumption data (FC) or hydrogen production data (HP) from national statistics may be
used in the Tier 1 methods. For feedstock data obtained in tonne, conversion to GJ can be done by using thedefault calorific values in the Ch. 1. Vol. 2 of 2006 IPCC Guidelines 6. If data on feedstock consumption orhydrogen production are not available, hydrogen production capacity data might be combined with a utilization
factor to estimate the hydrogen production in the Tier 1a method. The selection of activity data should aim tominimise the risk of any gaps or double-counting (Box 3.16) with hydrogen production from non-emissive
technologies, or from partial oxidation technologies and fuel combustion already included in other inventory
estimates.
The feedstock requirement factor (FRF) converts the production of hydrogen into the corresponding
consumption of feedstock. The default values are given in Table 3.30. The carbon content factor (CCF) converts
the feedstock into carbon equivalents, while 44/12 converts the carbon into CO2.
It is good practice to estimate of the fossil and biogenic emissions separately, based on the respective fossil andbiogenic carbon shares, and to allocate the biogenic emissions to a memo item and exclude it from the Hydrogenproduction sector. If the biogenic part cannot be estimated, it is good practice to assume that all feedstock isfossil. If no data on recovered CO2 could be obtained, it is good practice to assume that the recovery is zero.
If activity data and factors for all the Tier 1 methods are available, it is good practice to use the method giving
the lowest uncertainty.
6 For plastic gasification the NCV value is given in the footnote to Table 3.30.

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TIER 2 METHODThe Tier 2 methods use national or regional level activity data together with country-specific factors and data on
recovered CO2 to derive emissions, and should be used when hydrogen production is a key category and plantspecific activity data are not available. The activity data used in the Tier 2 method must be split by type of
feedstock. The CO2 emissions are estimated as follows:
EQUATION 3.47 (NEW)CO2 EMISSIONS FROM HYDROGEN PRODUCTION – TIER 2C

Eco2=∑ ( FC • CCF • 44 12) − R
j

j

j

co2

EQUATION 3.48 (NEW)CO2 EMISSIONS FROM HYDROGEN PRODUCTION – TIER 2B

Eco2=∑ ( HP • FRF • CCF • 44 12) − R
j

j

j

j

co2

Where:
ECO2= emissions of CO2, tonne

FCj= feedstock consumption in production of pure hydrogen as main product, feedstock j, GJ

HPj= pure hydrogen produced as main product, feedstock j, tonne

FRFj = feedstock requirement per unit of output, feedstock j, GJ feedstock / tonne hydrogen produced
CCFj = carbon content factor, feedstock j, tonne C / GJ feedstock
RCO2 = CO2 recovered, tonne
The equations used in the Tier 2 methods are equal to those used in the Tier 1 method labelled the same letter,the only difference between the two Tier levels being that country-specific factors are needed at the Tier 2 level.
Aggregate hydrogen production data (HPj) or feedstock consumption data (FCj) from national statistics may be
used in the Tier 2 method. If activity data and factors for both Tier 2 methods are available, it is good practice to
use the method giving the lowest uncertainty. It is good practice to use feedstock requirement factors (FRFj)
reflecting whether internal or external energy sources are used to heat the process. If no information on internal
vs. external energy source is available, it is good practice to use FRFjs for internal energy sources and to notethat the information is missing. Double counting with other sectors should be avoided (Box 3.16).
The FRFj converts the production of hydrogen into the corresponding consumption of feedstock. The carbon
content factor (CCFj) converts the feedstock into carbon equivalents, while 44/12 converts the carbon into CO2.
It is good practice to estimate of the fossil and biogenic emissions separately, and to allocate the biogenic
emissions to a memo item and exclude it from the Hydrogen production sector. A fuel containing a fossil and abiogenic part should be split according to the respective fossil and biogenic carbon shares. If country-specificfactors and/or an adequate split of the activity data by type of feedstock are not available and Hydrogenproduction is not a key category, it is good practice to use the Tier 1 method.

TIER 3 METHODThe Tier 3 methods use process- and plant-level activity data and factors together with data on recovered CO2
and stored amounts of solid carbon to derive emissions. The CO2 emissions are estimated as follows:
EQUATION 3.49 (NEW)CO2 EMISSIONS FROM HYDROGEN PRODUCTION – TIER 3C

=
Eco2

3.44

∑ ( FC • CCF • 44 12) − ( R
j ,n

j ,n

j ,n

co2

+ Sc • 44

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Chapter 3: Chemical Industry Emissions

EQUATION 3.50 (NEW)CO2 EMISSIONS FROM HYDROGEN PRODUCTION – TIER 3B=
Eco2∑ ( HPi , j ,ni , j ,n• FRFi , j ,n • CCF j ,n • 4412

) − ( Rco2 + Sc • 44

12)

Where:
ECO2= emissions of CO2, tonne

FCi,j.n= feedstock consumption in production of pure hydrogen as main product, process i andfeedstock j and plant n, GJ

HPi,j,n= pure hydrogen produced as main product, process i and feedstock j and plant n, tonne

FRFi,j.n = feedstock requirement per unit of output, process i and feedstock j and plant n, GJ feedstock /tonne hydrogen produced
CCFi,j,n = carbon content factor, process i and feedstock j and plant n, tonne C / GJ feedstock
RCO2= CO2 recovered, tonneSC= stored solid carbon, tonne

Plant, process and feedstock specific activity data and factors should be obtained from the hydrogen producers.
Double counting with other sectors should be avoided (Box 3.16). If activity data and factors for both Tier 3
methods are available, it is good practice to use the method giving the lowest uncertainty.
The FRFs should take into account whether or not the fuel used to heat the process is derived from the feedstock(i.e. internal or external energy source). Emissions from fossil and biogenic fuels should be estimated separately,
and the biogenic emissions should be allocated to a memo item and excluded from the Hydrogen production
sector. Fuels containing a fossil and a biogenic part should be split according to the respective fossil andbiogenic carbon shares.
Stored solid carbon here refers to solid carbon or coke formed unintentionally during the production process anddisposed of as waste (i.e., not combusted at the production facility). Where no information on the carbon content
in the stored solid carbon is available, it is good practice to assume that it is pure carbon. It is good practice toexclude stored solid carbon from the estimated emissions in the Hydrogen production sector. In the Hydrogenproduction sector, stored solid carbon does not include recovered CO2 sent to permanent storage.
If plant, process and feedstock specific activity data and factors are not available and emissions from hydrogenproduction is a key category, it is good practice to use a Tier 2 method. If emissions from hydrogen production is
not a key category, a Tier 1 method may be used.

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Figure 3.20 (New)

Decision tree for estimation of CO 2 emissions from hydrogen production
Box 7: Tier 3c

Start

Use the plant specific feedstock
consumption data and factors as basis for
the Tier 3c method, and subtract
recovered CO2 and stored solid C.

Yes

Box 6: Tier 3b
Are plant
specific activity data, factors,
recovery1 and storage2
available?

Yes

Are
plant specificconsumption data
available?

Use the plant specific hydrogenproduction data and factors as basis for
the Tier 3b method, and subtract
recovered CO2 and stored solid C.

No

No

Are
feedstock specificactivity data, country
specific factors, and national
recovery1 and storage2
available?

Box 5: Tier 2c

Yes

Are
consumption databy feedstock
available?

Use the feedstock consumption data andcountry- specific factors as basis for the
Tier 2c method, and subtract recovered
CO2 and stored solid C.

Yes

Box 4: Tier 2b
No

Use the hydrogen production data andcountry- specific factors as basis for the
Tier 2b method, and subtract recovered
CO2 and stored solid C.

No

Box 3: Tier 1c

Is this a key
category3?

Yes

No

Are
feedstock specificactivity data andnational recovery1
available?

Yes

Are
consumption databy feedstock
available?

Yes

Use the feedstock
consumption data anddefault feedstock
specific factors as
basis for the Tier 1cmethod, and subtract
recovered CO2.

No

No

Box 2: Tier 1b
Collect data for the Tier 2
or Tier 3 methods.

Arenational total
activity data
available?

Yes

Use the hydrogen production data anddefault feedstock specific factors as
basis for the Tier 1b method, andsubtract recovered CO2.

No

Box 1: Tier 1aCollect data for the Tier 1
method or higher.

Use national hydrogen production data if
available, or production capacity data, asbasis for the Tier 1a method. Subtract
recovered CO2 or assume zero recovery.

Note:
1

Recovery = annual mass of CO2 recovered from the hydrogen production emissions.

2

Storage = annual mass of solid C generated in the hydrogen production emissions and disposed of as waste.

See Volume 1 Chapter 4, Methodological Choice and Identification of Key Categories (noting Section 4.1.2 on limited resources), for
key categories and use of decision trees.

3

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3.11.2.2 C HOICE OF EMISSION FACTORSThe feedstock requirement factor (FRF) converts the production of hydrogen into the corresponding
consumption of feedstock (raw material and fuel). The carbon content factor (CCF) converts the amount offeedstock in GJ into tonne of carbon.

TIER 1 METHOD
In the Tier 1c method, it is good practice to use the default feedstock specific CCFs in Table 3.30, and in the
Tier 1b it is good practice to use the default feedstock specific FRFs and CCFs. These default values often
represent midpoint or mean values of data sets (as determined by expert analysis). In the Tier 1a method, it isgood practice to use the default FRFj and CCFj for the feedstock j giving the highest combined value (FRFj *CCFj) for the factors. This feedstock j should be among the commonly used feedstock types in the country, andthe FRFj and CCFj should be used for the entire production. If no qualitative information on feedstock types isavailable, the general default factors might be used. The general default factors are weighted averages of therespective feedstock specific factors, based on global production figures.
TABLE 3.30 (NEW)DEFAULT FEEDSTOCK REQUIREMENT FACTORS AND CARBON CONTENT FACTORS FOR HYDROGEN PRODUCTION1,2
Production Process
Steam reforming
Natural gas reforming
Liquified petroleum gas reforming
Naphtha reforming
Methanol reforming
Biosteam reforming, other liquid(bioethanol)
Gasification
Coal gasification (coking coal)3
Plastic4 gasification
Mixed waste gasification(non-biomass fraction)
Wood waste gasification
Wood sludge gasification
Black liquor gasification
GeneralDefault

Feedstock Requirement Factor (FRF)(GJ feedstock/tonne H2) ± Uncertainty1

Carbon Content Factor (CCF)2(tonne C / GJ feedstock)
Default
0.01530.01720.02000.0188Lower
0.01480.01680.01890.0186Upper
0.01590.01790.02080.01900.02170.01830.0260215 (± 20%)185 (± 10%)275 (± 15%)0.02580.02000.02380.01600.02760.02400.02500.02000.0330260 (± 10%)195 (± 15%)150 (± 10%)0.03050.03050.02600.02590.02590.02200.03600.03600.0300175 (± 30%)5

0.018360.01486

0.02766

165 (± 10%)165 (± 15%)165 (± 15%)165 (± 20%)175 (± 20%)

Notes:
1 When uncertainty range is not given in the referenced literature for a given factor, a default uncertainty of ±20% is chosen. When only
one literature value is found, a default minimum uncertainty of ±15% is chosen.
2 The factors are also found in Table 1.3 Default values of carbon content in Volume 2.
3 Hydrogen production from coal is currently dominated by use of coking coal as feedstock. Where coal of other quality is used, then it isgood practice in the Tier 1 method to: (i) apply the FRF for coking coal with an uncertainty range of ±30% when the Tier 1b method isused, and (ii) apply a default CCF that reflects the specific coal type (e.g. lignite, sub-bituminous, other bituminous) as presented in Table
1.3 of Volume 2.
4 Mixed plastic. For CCF the value for "other petroleum products" in Vol.2 Ch. 1 Table 1.3 is used. NCV = 32.0 MJ/kg.
5 Estimated by weighted average of natural gas (49%), LPG/naphtha (29%) and coal (18%), current production methods, based on global
production statistics (remaining 4% is mainly produced by electrolysis of water). Uncertainty set to cover the ranges of these three
feedstock types, which are by far the most common at present.
6 Estimated by weighted average of natural gas (49%), LPG/naphtha (29%) and coal (18%), current production methods, based on global
production statistics (remaining 4% is mainly produced by electrolysis of water). Lower uncertainty range is from steam reforming of
natural gas, upper uncertainty range is from gasification of coal.
Source:Amgad et al., 2013; API, 2009; Cormos, 2011; DOE, 2017; Edwards et al., 2014; Geissler, et al., 2001; Iwasaki, 2003; JARI, 2011;
Schiebahn et al., 2015; Sørensen, 2011; Themelis et al., 2011; The Pacific Northwest National Laboratory, 2017; US Department ofEnergy, 2017; Wallman et al., 1998.

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TIER 2 METHOD
For the Tier 2c method it is good practice to use country-specific CCFs, and to quality check these factors
against the default factors in Table 3.30.
For the Tier 2b method, it is good practice to use country-specific FRFs and CCFs, and to quality check thesefactors against the default factors in Table 3.30 to ensure good factor quality.

TIER 3 METHOD
Plant-level activity data on total fuel and feedstock requirement combined with CCF or hydrogen production
combined with CCF and FRF by production technology and feedstock type provide the most rigorous data for
calculating CO2 emissions from hydrogen production. In the Tier 3 methods, it is good practice to use plant andfeedstock specific CCFs, or plant, process and feedstock specific FRFs and CCFs, and to quality check thesefactors against the default factors in Table 3.30 to ensure good factor quality. The carbon content (CCF) is a key
emission factor variable for deriving the quantity of CO2 emissions in all Tier methods. Derivation of emissions
using plant-level hydrogen production also depends on an accurate estimate of the fuel requirement per unit ofoutput (FRF), along with information on the other variables.

3.11.2.3 C HOICE OF ACTIVITY DATA
For all methods, it is good practice to gather activity data on hydrogen production from national or regional data
sources (e.g. statistical agencies, regulatory agencies, plant operators, trade associations, researchers) in order tominimise the risk of gaps and double-counting in the inventory (Box 3.16). Data on CO2 recovered fromhydrogen production (for use downstream, or to storage) should also be sought. It is good practice to use the Tiermethod giving the lowest overall uncertainty.

TIER 1 METHOD
National or regional level activity data may be used in the Tier 1 methods:•

In the Tier 1c method, feedstock consumption data by type of feedstock should be used;•

In the Tier 1b method, hydrogen production data by type of feedstock should be used;•

In the Tier 1a method, total hydrogen production data should be used.

If feedstock consumption or hydrogen production data are not available for the Tier 1c method, production
capacity data may be used instead. If the inventory compiler can document that utilisation for a year was below
capacity, it is good practice to multiply the total national or regional production capacity by a default capacity
utilisation factor of 80 percent ± 10 percent (i.e., a range of 70-90 percent) through the entire time-series, or acountry-specific capacity utilisation factor. If production capacity data are used for the base year and actual
production data are used for later years, a country-specific capacity utilisation factor should be used for all years
with production capacity data. It is good practice to estimate this capacity utilisation factor as the actualhydrogen production divided by the production capacity of at least one overlapping year adjacent to the years
with production capacity data.
It is good practice to obtain the biogenic share of the feedstock, to estimate the CO2 emissions to be excluded
from the Hydrogen production sector and reported in a memo item. If the biogenic share cannot be obtained, it isgood practice to assume that all feedstock is fossil.
Where feedstock data are obtained in tonnes, the default calorific values in Ch. 1, Vol. 2 of 2006 IPCC
Guidelines can be used to convert to energy units.

TIER 2 METHODThe Tier 2 methods requires the same activity data as the Tier 1 method labelled with the same letter (i.e. thesame sub-Tier). The biogenic share of the feedstock should be obtained from the producers, and the estimatedbiogenic CO2 emissions should be excluded from the Hydrogen production sector and reported in a memo item.

TIER 3 METHODThe Tier 3 methods require the collection of plant-level activity data by production method and type of feedstock,
including plant-level data on recovered CO2, where applicable. Production capacity data should not be used. The
biogenic share of the feedstock should be obtained from the producers, to estimate the CO2 emissions to be
excluded from the Hydrogen production sector and reported in a memo item.
Where access to plant-level data may be limited due to confidentiality, then inventory compilers should refer toguidance presented in Volume 1, Chapter 2 Approaches to Data Collection.

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3.11.2.4 C OMPLETENESS
In countries where only a subset of plants report data for the Tier 3 method or where there is a transition fromTier 2 to Tier 3, it may not be possible to report according to Tier 3 for all facilities during the transition. Where
data for the Tier 3 method is not available for all plants, Tier 2 could be used for the remaining plants. If a mix ofTiers is used, it is good practice to report the lower Tier as the applied method. If the estimation uses a mix of cand b Tiers, it is good practice to report as method the one giving the highest uncertainty.
To avoid double counting, emissions from the production of hydrogen as a by-product or intermediate productbeing reported under other sectors, including Ammonia production and Methanol production (IPPU), Petroleum
refining (Energy), must be excluded from hydrogen production.
Recovered CO2 which is used in downstream sectors or sent to permanent storage should be subtracted fromhydrogen production, to avoid double counting with downstream sectors.
Biogenic CO2 emissions should be excluded from the Hydrogen production sector and allocated to a memo item,
to avoid double counting with the AFOLU sector.
See Box 3.16 for more details on double counting and gaps.

3.11.2.5 D EVELOPING A CONSISTENT TIME SERIES
Recalculation of CO2 emissions should be made for all years whenever emission calculation methods arechanged (e.g., if the inventory compiler changes from the use of default values to actual values determined at theplant level). If plant-specific data on hydrogen production and consumed feedstock, and data on recovered CO2
and stored C, are not available for all years in the time series, it will be necessary to consider how current data
can be used to recalculate emissions for previous years. It may be possible to apply current factors to data fromprevious years, provided that the production technology has not changed substantially.
Recalculation is required to ensure that any changes in emissions trends are real and not an artefact of changes in
estimation methods. It is good practice to recalculate the time series according to the guidance provided inVolume 1, Chapter 5.

3.11.3

Uncertainty assessment

3.11.3.1 E MISSION FACTOR UNCERTAINTIESIt is good practice to obtain uncertainty estimates at the same level (i.e. national, regional or plant) as the activity
data. In case of plant level data, the uncertainty should be lower than uncertainty values associated with default
values. The same applies to country-specific factors.
Feedstock requirement factors (FRFs): Uncertainty in the default FRFs arise from variation between plants in
how efficiently the hydrogen is produced. Three factors are decisive to the level of uncertainty: 1) the process
efficiency, i.e. how much fuel is combusted for process heat per tonne of produced hydrogen, 2) the chemicalcomposition of the feedstock, i.e. the hydrogen to carbon ratio, and 3) the specific energy content of thefeedstock. Feedstock specific factors have lower uncertainty than the general default factor, because the latter
contain the variation in process efficiency, chemical composition and specific energy content between different
types of feedstock. Plant specific factors have even lower uncertainties. Estimation methods using FRFs (Tier b
and a methods) have higher overall uncertainty than methods not using the fuel requirement factors (Tier cmethods), ceteris paribus, because the Tier b and a methods include one uncertain element (FRF) that is notincluded in the Tier c methods.
Carbon content factors (CCFs): Uncertainty in the default CCFs is resulting from variation in 1) the chemicalcomposition of the feedstock, i.e. the hydrogen to carbon ratio, and 2) the specific energy content of thefeedstock. Uncertainty arise from variation in composition and energy content of a specific material used as
feedstock (for example between different types of coal), and from variation in composition and energy content offeedstocks with a heterogeneous composition (for example waste). Feedstock specific factors have lower
uncertainty than the general default factor, because the latter contain the variation between different types offeedstock. Plant specific factors have even lower uncertainties.
In the Tier 1a method, if the highest default CCF value among the feedstock types used in the country is used forthe entire production, a country-specific uncertainty estimate or alternatively a default increase in the remaining
uncertainty of 20 percentage points in the downward direction (only) should be used.

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3.11.3.2 A CTIVITY DATA UNCERTAINTIES
Where the activity data are obtained at the plant-specific level, uncertainty estimates may be obtained directlyfrom the hydrogen producers. These activity data are likely to be highly accurate (i.e., with uncertainty as low as±2 percent). This includes uncertainty estimates for feedstock use (Tier c methods) or hydrogen production (Tierb and a methods), as well as CO2 recovered and stored solid carbon. Data that are obtained from national
statistical agencies usually do not include uncertainty estimates. It is good practice to consult with national
statistical agencies to obtain information on any uncertainty. Where national statistical agencies collect data fromthe population of hydrogen production facilities, uncertainties in national statistics are not expected to differ
from uncertainties established from plant-level consultations. Where uncertainty values are not available fromother sources, a default value of ±5 percent can be used for activity data from national statistical agencies.
If plant-specific data are not available for all years in the time series, and current data are used to recalculate
emissions for previous years, the uncertainty in emission estimates might increase due to changes in production
technology. It is good practice to increase the uncertainty values accordingly.
Where uncertainty values are not available from other sources, a default increase of ±20 percent in theuncertainty can be used for previous reference years estimates based on data on current years.
Where estimates are made to split the fossil and biogenic parts of a mixed feedstock in the Tier 1 and 2 methods,
a default uncertainty of ±5 percent should be added to the biogenic part if it is based on reported figures, and ±20
percent if it is estimated. The same uncertainty, in absolute amounts, should be added to the fossil part.

3.11.4

Quality Assurance/Quality Control (QA/QC),
Reporting and Documentation

3.11.4.1 Q UALITY A SSURANCE /Q UALITY C ONTROL
It is good practice to conduct quality control checks as outlined in Volume 1, Chapter 6. More extensive quality
control checks and quality assurance procedures are applicable, if higher tier methods are used to determine
emissions. Inventory compilers are encouraged to use higher tier QA/QC for key categories as identified inVolume 1, Chapter 4.

Comparison of emission factors
Inventory compilers should check if the estimated factors are within the range of default factors, and also ensurethat the emission factors are consistent with the values derived from analysis of the process chemistry. For
example, the CO2 generation rate based on natural gas should not be less than 5.46 tonne of CO2 per tonne ofhydrogen produced 7. If the emission factors are outside of the estimated range of default factors, it is goodpractice to assess and document the plant-specific or country-specific conditions that account for the differences.

Comparison of activity data
It is useful to collect and report activity data comprising both process input data (feedstock consumption) andprocess output data (hydrogen production), to control the relation between them.
It is good practice to cross-check that all emissions from downstream use of recovered CO2 is accounted for in
the corresponding downstream IPPU or other sector(s).

Plant-specific data check
The following plant-specific data are required for adequate auditing of emissions estimates at the Tier 3 level:•

Calculations and estimation method;•

List of assumptions;•

Documentation of any plant-specific measurement method, and measurement results;

QC procedures in use at the site should be directly referenced and included in the QC plan. If the measurement
practices were not consistent with QC standards, the inventory compiler should reconsider the use of these data.
7 Method: 44.011 tonne CO / 8.064 tonne H = 5.46 tonne of CO per tonne of H produced, based on molar weights of
2
2
2

12.011 (C), 16.00 (O), 1.008 (H) and 100 percent production yield (i.e. no by-products produced, no fuel combustion to
produce heat and no feedstock loss in the production process).

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3.11.4.2 R EPORTING AND D OCUMENTATION
It is good practice to document and archive all information required to produce the national emissions inventory
estimates as outlined in Volume 1, Section 6.11.
Some examples of specific documentation and reporting that may be relevant to this source category areprovided below:•

Description of the method used;•

Number of hydrogen main product production plants;•

Feedstock requirement factors;•

Carbon content factors;•

Feedstock consumption data;•

Production data;•

Production capacity;•

CO2 recovery data;•

Downstream use and permanent storage of recovered CO2;•

Stored solid carbon data;•

Any other assumptions.

Ideally, plant operators should supply this information to the inventory compiler for compilation, and alsoarchive the information at the site. Plant operators should also log and archive the measurement frequencies andinstrumental calibration records where actual plant measurements are made.
Where such inventory data (e.g. plant- or company-specific production data) may be considered confidential (e.g.
where there are only one or two producers in a country), then inventory compilers should refer to guidance
presented in Volume 1, Chapter 2 Approaches to Data Collection. In these cases, operators and the inventory
compiler should seek to determine the level of aggregation at which information can be reported while still
protecting confidentiality. Detailed information including instrumentation records should still be archived at theplant level.
It is not practical to include all documentation in the national inventory report. However, the inventory should
include summaries of methods used and references to source data such that the reported emissions estimates aretransparent and steps in their calculation may be retraced.

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ANNEX 3A.1 DEFAULT EMISSION FACTORS FORSECTION 3.10.2 EMISSIONS FROMPRODUCTION OF FLUORINATEDCOMPOUNDS (OTHER THAN HFC-23
EMISSIONS FROM HCFC-22 PRODUCTION)
This annex provides background information for the Tier 1 default emission factors for fluorinated greenhousegases (GHG) from fluorochemical production, that are provided in section 3.10.2 in the 2019 Refinement to the2006 IPCC Guidelines. The first section discusses the default emission factors for SF6 and NF3 production basedon literature search, and the second section discusses the default emission factor estimated from the data reported
to the U.S. Greenhouse Gas Reporting Program.

EXECUTIVE SUMMARYThe Tier 1 default emission factor for production of fluorinated gases other than SF6 and NF3 was developed
based on emissions and throughput (production and transformation) information reported to the U.S. Greenhouse
Gas Reporting Program (GHGRP). The factor is intended to represent uncontrolled emissions. Under the
GHGRP, fluorinated GHG emissions are reported annually on a facility basis and include facilities with andwithout abatement. Depending on the year, 14 to 16 fluorochemical production facilities have reported under the
Program. Facilities that abate their emissions report their level of abatement for each process as a range. To
develop emission factors on an uncontrolled basis, the pre-abatement emissions of each facility were estimatedusing the arithmetic averages of the abatement ranges reported by that facility for its processes. Then, for eachfacility, this estimate was divided by the total quantity of fluorinated gases produced or transformed by thatfacility to obtain an uncontrolled emission factor for that facility and year. This was done for all six years forwhich the US EPA had data at the time the factor was developed. For each facility, the emission factors for eachyear were then averaged over the six years of reporting, and the resulting facility averages were averaged toobtain the default factor. Because the reporting U.S. facilities use multiple manufacturing methods to produce awide array of fluorochemicals, averaging the facility-specific emission factors is expected to provide a default
emission factor that is applicable where the manufacturing method is unknown, as is often the case in a Tier 1
calculation.
The uncertainty of the default emission factor was assessed using several methods, including sensitivity analyses,
Monte Carlo analysis, and statistical analyses. As discussed further below in section 3A.1.5, these analyses
showed that the selected factor was robust despite uncertainties in the reported data, such as the reporting ofdestruction efficiencies as a range rather than a single value. However, the analyses also indicated that theuncertainty in the emission factor for any single facility is quite large, and is dictated by the fact that true
uncontrolled emission rates naturally vary from facility to facility depending on the fluorochemicals produced
and the type of manufacturing method used to produce them.

3A.1.1 BACKGROUND INFORMATION FOR SECTION 3.10.2 TIER 1
DEFAULT EMISSION FACTORS – FROM THE LITERATURE
The literature shows a broad range of emission factors for different gases and even for the same gas when it isproduced for different applications. For SF6 produced in Japan, a factor of 0.08 kg emitted/kg produced wasfound for facilities whose customers require highly purified SF6 gas (e.g., semiconductor manufacturing). The
emission factor is relatively large because of handling losses during disposal of residual gas (i.e., the ‘heel’ thatis not used or recycled) in returned cylinders (Suizu, 1999). An SF6 emission factor has been reported as 0.03 kg
emitted/kg of sales (O’Connell, 2002).
U.S. and Japanese NF3 manufacturers have reported an emission factor for NF3 emissions of 0.02 in 2009, with agoal of eventually achieving an emission factor of 0.005 kg emitted/kg produced (it is not known whether the
0.005 factor is based on pre-abatement emissions or controlled, post-abatement emissions) (Fthenakis, 2010).
CF4 and N2O are generated as a by-product during NF3 manufacture, and N2O and CF4 can be formed at rates of0.03 kg emitted/kg produced and less than 0.01 kg emitted/kg produced, respectively, relative to the mass of NF3
formed during electrolysis (these emission factors are on an uncontrolled, pre-abatement basis) (Tasaka, 2004;
2007). Some process-specific emission factor data are available from commercially available life cycle
assessment software; these EFs may be acceptable should sufficient documentation of their units, source data,and calculation exist.
In another reference focused on SF6 produced in Germany, an emission factor of 0.002 kg emitted/kg of the total
quantity of SF6 produced was found for facilities whose customers do not require highly purified SF6 gas (e.g.,
electrical equipment, insulated windows) (Preisegger, 1999). Unfortunately, it is not known whether the 0.002

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kg emitted/kg produced factor is based on pre-abatement emissions or controlled, post-abatement emissions, andtherefore it should not be used for Tier 1 estimates. The authors note the value here for informational purposes
and to acknowledge that the data were reviewed for the Tier 1 methodology.

3A.1.2 BACKGROUND INFORMATION FOR SECTION 3.10.2 TIER 1
DEFAULT EMISSION FACTORS – ALL OTHER FLUORINATED GHG
3A.1.2.1

Source of Data

The U.S. GHGRP 8 requires certain facilities that emit greenhouse gases (GHGs) and certain suppliers of fossil
fuels and industrial GHGs to report their emissions or supplies (along with other relevant data) annually to the
US Environmental Protection Agency (EPA). In general, reporting requirements apply to facilities or suppliers
that meet or exceed thresholds that are equivalent to emissions of 25,000 metric tonne of CO2 equivalent (CO2eq.)
per year. Facilities and reporters collect data for the calendar year and report those data to EPA electronically inthe following year by March 31. 9 The US EPA verifies 10 the data and then publishes it. The GHGs covered
include carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs),
perfluorocarbons (PFCs), sulphur hexafluoride (SF6), and other fluorinated gases (e.g., nitrogen trifluoride,hydrofluoroethers [HFEs], perfluorinated amines, etc.).
The default emission factor for fluorochemical production is based on data reported under two sections of the
GHGRP regulation—subpart L, Fluorinated Gas Production, and subpart OO, Suppliers of Industrial Greenhouse
Gases—for reporting years (RY) 11 2011 to 2016. Under subpart L, facilities that produce a fluorinated gas (otherthan HCFC-22 12 ) must report their fluorinated GHG emissions from the production and transformation offluorinated gases, from venting of residual fluorinated GHGs from containers, and from destruction ofpreviously produced fluorinated GHGs. The emissions reported from production and transformation include bothemissions from process vents and emissions from equipment leaks. Under subpart OO, fluorinated GHG
suppliers (including fluorinated GHG producers) must report the quantities of each fluorinated GHG that they
produce, transform, destroy, import, or export.

3A.1.2.2
FactorData Used in Development of the Fluorinated GHG Emissions

The emission factor was developed from: (1) the emissions from production and transformation processes andemissions from venting of residual fluorinated GHGs from containers, and (2) the quantities of fluorinatedGHGs produced and transformed. Facilities reporting emissions under subpart L provide information onemissions from production and transformation processes at two levels of aggregation and in two metrics:•

For the facility as a whole, emissions are provided by specific fluorinated GHG compound in metric tonne
where the facility makes more than one product and where the emissions of that compound equal or exceed
1,000 metric tonne CO2eq. across all processes. Where total emissions of a compound across all processes
are less than 1,000 metric tonne CO2eq., emissions are reported by fluorinated GHG group 13 in metric tonne
CO2eq. Where the facility makes only one product, emissions are reported by compound when thatcompound is the same as the product; otherwise they are reported by fluorinated GHG group in metric tonne
CO2eq.

•For each production and transformation process at the facility, emissions are reported by process andfluorinated GHG group in metric tonne CO2eq.

The global warming potentials (GWPs) used to calculate CO2-equivalent emissions are drawn from the IPCC
Fourth Assessment Report (AR4), IPCC Fifth Assessment Report (AR5), or then a default GWP is used. For
8 The GHGRP regulation can be found in the U.S. Code of Federal Regulations (CFR) at Title 40, Part 98. For backgroundinformation on and data from the GHGRP, please see <https://www.epa.gov/ghgreporting>
Final rule. (74 FR 56260). October 30, 2009.
10 For information on how EPA verifies data submitted under the GHGRP, please see<https://www.epa.gov/sites/production/files/2015-07/documents/ghgrp_verification_factsheet.pdf>.
9 Mandatory Reporting of Greenhouse Gases.

11 The term “reporting year (RY)” refers to the year in which the emissions occurred.

12 Facilities that produce HCFC-22 are required to report their emissions under a separate part of the GHGRP, Subpart O. The

emission factor being developed here is intended to apply to production of fluorochemicals other than HCFC-22 (which iscovered in section 3.10.1 of the F), and therefore emissions from HCFC-22 production are not discussed further here.
13 There are twelve fluorinated GHG groups, each of which encompasses a set of GHGs with roughly similar atmosphericbehaviour, including similar GWPs and atmospheric lifetimes. These include, e.g., fully fluorinated GHGs such as PFCs
and SF6, HFCs with two or fewer hydrogen-carbon bonds, HFCs with more than two carbon-hydrogen bonds, unsaturated
HFCs and PFCs, etc. (See Table A3.1.3 for a full list.) Compounds that do not have GWPs in either the Fourth Assessment
Report (AR4) or AR5 are assigned a default GWP that is generally based on the average GWP for the fluorinated GHG
group of which the compound is a member.

2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories

3.53

Volume 3: Industrial Processes and Product Use

most fluorinated GHG groups, the default GWP is the average of the GWPs of all the fluorinated GHGs in thatgroup that have GWP values in AR4 or AR5. 14 Where we use emissions reported in CO2eq. in our calculations,
we back-calculate the emissions in metric tonne using the same set of GWPs used to calculate the CO2eq.
emissions.
For the processes, facilities also report the range into which the destruction efficiency (DE) of each process falls.
(The DE is based on the extent to which emissions from process vents are controlled. Emissions from equipment
leaks are not included in the DE calculation.) Table 3A.1.1 provides the DE ranges available for facilities toreport and the DE assumptions for each.
TABLE 3A.1.1 (NEW)
DESTRUCTION EFFICIENCY RANGE VALUES USED TO ESTIMATE PRE-ABATEMENT EMISSIONS FOR PRODUCTION AND
TRANSFORMATION PROCESSESDE ranges

Lower Bound

Upper Bound

Arithmetic Mean ofBoundsGeometric Mean ofBounds>=0% to <75%

0.0

0.75

0.375

0.500

>=75% to <95%

0.75

0.95

0.85

0.888

>=95% to <99%

0.95

0.99

0.97

0.978

>=99%

0.99

0.9999

0.995

0.999

Facilities reporting emissions of residual fluorinated GHGs from container venting report emissions in metrictonne of each fluorinated GHG.
The activity data for the emission factor was compiled from reporting of the quantities of fluorinated GHGs
produced and transformed that were reported under subpart OO.

A3.1.2.3
Processes

Calculation of Emissions from Production and Transformationa.
Actual Emissions by Specific Fluorinated GHG for Production andTransformation Processes

Actual emissions of specific fluorinated GHGs reported under subpart L for production and transformation
processes are provided in Table 3A.1.2. Table 3A.1.2 provides actual emissions by specific fluorinated GHG for
production and transformation processes in metric tonne, and also provides actual GWP-weighted emissions byspecific fluorinated GHG for production and transformation processes in metric tonne CO2eq. Actual emissions
are those emissions that actually occur to the atmosphere and reflect the level of control for the process. These
totals include only the portion of production and transformation process emissions that are reported by specificfluorinated GHG (approximately 98 percent of production and transformation emissions in metric tonne
CO2eq.). 15b.

Actual Emissions by Fluorinated GHG Groupc.

Estimated Emissions Prior to Control by Fluorinated GHG Group

Actual emissions of fluorinated GHGs reported under subpart L are provided by fluorinated GHG group for eachproduction and transformation process. Table 3A.1.3 provides actual fluorinated GHG emissions in metric tonne
CO2eq. by fluorinated GHG group. The group totals include all emissions from production and transformation
processes.
Uncontrolled emissions (i.e., pre-abatement emissions) for production and transformation processes were
estimated based on the destruction efficiency (DE) range provided by facilities when they reported on eachprocess, along with the actual fluorinated GHG emissions reported in metric tonne CO2eq. Because facilities
provide the range in which the DE falls rather than the exact DE, an assumption of the true DE must be made.
14 For fluorinated GHG groups that have average GWPs below one, including unsaturated HFCs and PFCs, fluorotelomer

alcohols, and compounds with carbon-iodine bonds, a default value of one is used, but as discussed further below, thesecompounds are excluded from this analysis.

15 The tables in this discussion and subsequent estimated pre-abatement emission discussions exclude compounds with GWPs

near or below 1 (i.e., unsaturated PFCs, HFCs, etc.; fluorotelomer alcohols; and fluorinated GHGs with carbon-iodide
bonds) because these compounds account for only 0.01 percent of the GWP-weighted emissions reported under subpart L
and, as discussed further in section A3.1.5, including them introduces large uncertainties into the emission factor expressedin units of metric tonne.

3.54

2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 3:Chemical Industry Emissions

TABLE 3A.1.2 (NEW)ACTUAL EMISSIONS FROM PRODUCTION AND TRANSFORMATION PROCESS REPORTED BY SPECIFIC FLUORINATED GHG UNDER SUBPART L OF THE GHGRP (CONSIDERING CONTROLS) (APPROXIMATELY 98
PERCENT OF P/T PROCESS EMISSIONS IN METRIC TONNE CO2 EQUIVALENT), METRIC TONNE AND METRIC TONNE CO2 EQUIVALENTA
Fluorinated GHG Name

2011

2012

2013

2014

2015

2016

Sum
Total,
tonne

Cumu
lative
%

2011

2012

2013

2014

2015

2016

tonne

Sum
Total,
tonne
CO2eq.

%
tonne
CO2eq.

Cumul
ative
%

%

HFC-134a

266

222

208

203

227

147

1,273

20%

20%

380,008

317,799

297,074

290,333

324,151

210,574

1,819,938

5.0%

5.0%

HFC-23

191

214

198

112

81

53

849

13%

33%

2,829,581

3,166,284

2,934,831

1,661,087

1,191,554

778,851

12,562,188

34.4%

39.4%

HFC-125

152

151

156

151

136

63

808

12%

45%

533,042528,308

545,053

527,997475,389

219,4822,829,271

7.7%

47.1%

HFC-32

155

165

152

116

130

91

808

12%

58%

104,652

111,119

102,620

78,40887,501

61,176545,475

1.5%

48.6%

HFC-143a

136

127

128

100

93

102

685

11%

68%

607,421566,428

570,420446,846

413,610456,470

3,061,194

8.4%

57.0%

PFC-14 (Perfluoromethane)

60

77

58

47

46

54

342

5%

73%

445,137

568,391

428,165

346,613336,266

402,576

2,527,148

6.9%

63.9%

HFC-245fa

48

49

49

50

41

41

278

4%

78%

49,59549,96550,04851,51042,47742,371

285,966

0.8%

64.7%

Perfluorocyclobutane

53

35

26

29

28

52

223

3%

81%

546,574

362,868

268,346

296,849

290,191

535,633

2,300,460

6.3%

71.0%

HFC-227ea

26

25

35

24

25

23

158

2%

84%

84,27581,365

112,449

76,572

81,94372,729509,332

1.4%

72.4%

PFC-116 (Perfluoroethane)

21

20

40

17

23

2

123

2%

86%

250,244

246,574

485,921207,274

284,305

21,572

1,495,890

4.1%

76.4%

Nitrogen trifluoride

31

28

20

16

15

13

122

2%

87%

531,201

482,591

336,165

272,076

261,263

218,992

2,102,289

5.8%

82.2%

Octafluorotetrahydrofuran

19

25

40

23

6

5

117

2%

89%

188,440

253,010395,575

232,025

56,124

48,225

1,173,399

3.2%

85.4%

Hexafluoropropylene oxide

11

17

19

20

23

18

109

2%

91%

114,620

172,341

190,459

197,199

233,900

179,593

1,088,112

3.0%

88.4%

PFC-218 (Perfluoropropane)

12

7

48

16

3

3

89

1%

92%

106,887

62,557424,737

143,241

28,29823,976789,696

2.2%

90.6%

Pentafluoro(trifluoromethyl)cyclopropane

10

8

10

11

19

15

75

1%

93%

102,885

82,428103,221112,075

192,068

152,615745,292

2.0%

92.6%

HFE-449sl, (HFE-7100) Isomer
blend

11

11

12

9

9

11

62

1%

94%

3,191

3,264

3,578

2,734

2,598

3,195

18,559

0.1%

92.6%

PFC-5-1-14 (Perfluorohexane, FC
72)

12

8

8

10

13

6

57

1%

95%

109,192

76,50073,98095,154

118,276

56,068529,169

1.4%

94.1%

HFC-152a

9

9

12

0

0

21

51

1%

96%

1,089

1,152

1,491

0

0

2,633

6,366

0.0%

94.1%

Trifluoromethyl sulphur
pentafluoride

8

9

19

5

3

2

45

1%

97%

136,465

166,270

332,625

92,03847,63629,748804,783

2.2%

96.3%

1,1,1,2,2,3,3-Heptafluoro-3(1,2,2,2-tetrafluoroethoxy)-propane

0

0

4

7

6

15

33

1%

97%

3,019

3,162

24,892

42,564

41,90997,311

212,857

0.6%

96.9%

2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories

3.55

Volume 3: Industrial Processes and Product Use

TABLE 3A.1.2 (NEW) (CONTINUED)ACTUAL EMISSIONS FROM PRODUCTION AND TRANSFORMATION PROCESS REPORTED BY SPECIFIC FLUORINATED GHG UNDER SUBPART L OF THE GHGRP (CONSIDERING CONTROLS) (APPROXIMATELY 98 PERCENT OF
P/T PROCESS EMISSIONS IN METRIC TONNE CO2 EQUIVALENT), METRIC TONNE AND METRIC TONNE CO2 EQUIVALENT
Fluorinated GHG Name

2011

2012

2013

2014

2015

2016

Sum

%

Total,

tonne

tonne

Cumul
ative

2011

2012

2013

2014

2015

2016

%

Sum
Total,

4

5

3

2

2

6

21

0%

98%

Trifluoromethanesulfonyl fluoride

3

4

6

4

2

1

20

0%

98%

HFC-236fa

2

3

5

3

2

2

17

0%

98%

PFC-3-1-10 (Perfluorobutane)

2

2

6

3

1

2

15

0%

98%

Perfluorodiethyl ether

2

3

2

1

2

2

11

0%

Perfluorobutanesulfonyl fluoride

1

1

1

1

1

5

10

Sulfur hexafluoride

1

1

3

3

1

0

Pentafluoro(trifluoromethoxy)-ethane

2

1

3

1

1

0

Hexafluorooxetane

1

1

4

1

1

PFC-4-1-12 (Perfluoropentane)

2

1

1

1

Carbonyl fluoride

1

1

1

Trifluoroacetyl fluoride

1

1

HFC-43-10mee

1

Perfluoropropionyl fluoride%

42,053

0.1%

97.0%

9,072

6,125

6,552

8,400

12,221

7,502

3,111

2,799

40,584

0.1%

97.1%

22,15233,28547,91228,49718,093

14,821

164,760

0.5%

97.6%

17,853

13,34954,56623,017

9,143

18,817

136,746

0.4%

97.9%

99%

16,77929,44821,421

13,61916,460

16,236113,963

0.3%

98.3%

0%

99%

2,431

1,674

2,091

1,840

2,658

10,15520,850

0.1%

98.3%

10

0%

99%

28,99125,70973,50966,97523,181

5,910

224,276

0.6%

98.9%

8

0%

99%

19,298

10,78429,517

10,139

5,747

4,844

80,329

0.2%

99.1%

1

8

0%

99%

13,921

9,418

35,195

6,581

7,064

6,035

78,214

0.2%

99.4%

2

1

8

0%

99%

18,958

8,201

9,053

5,933

15,605

13,627

71,377

0.2%

99.6%

1

1

1

6

0%

99%

2,977

1,673

1,340

1,803

1,584

2,492

11,869

0.0%

99.6%

1

1

1

1

5

0%

99%

2,493

1,654

1,339

1,638

1,651

1,890

10,664

0.0%

99.6%

1

1

1

0

1

5

0%

100%

1,657

1,504

1,673

1,163

0

1,529

7,526

0.0%

99.6%

1

1

1

1

1

0

4

0%

100%

1,928

1,661

2,261

1,077

1,619

0

8,546

0.0%

99.7%

Perfluoro-2-(2-fluorosulfonylethoxy)
propyl vinyl ether

0

0

0

0

1

3

4

0%

100%

0

0

0

0

2,167

5,654

7,821

0.0%

99.7%

2,2,3,3,4-Pentafluro-4-(trifluoromethyl)oxetane

0

1

2

0

0

0

3

0%

100%

3,111

8,787

16,370

3,665

1,530

1,009

34,472

0.1%

99.8%

HFC-365mfc

0

0

3

0

0

0

3

0%

100%

0

0

2,620

0

0

0

2,620

0.0%

99.8%

PFC-6-1-12

1

1

0

0

0

0

3

0%

100%

8,867

10,099

1,078

1,110

2,219

0

23,373

0.1%

99.8%

Isobutyryl fluoride

2

0

0

0

0

0

2

0%

100%

4,668

0

0

0

0

0

4,668

0.0%

99.9%

3.56

7,776

3,462

4,604

11,015

Cumul
ative

CO2eq.

tonne
CO2eq.

2H-perfluoro(5-methyl-3,6-dioxanonane)

%
tonne

2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories

Chapter 3:Chemical Industry Emissions

TABLE 3A.1.2 (NEW) (CONTINUED)ACTUAL EMISSIONS FROM PRODUCTION AND TRANSFORMATION PROCESS REPORTED BY SPECIFIC FLUORINATED GHG UNDER SUBPART L OF THE GHGRP (CONSIDERING CONTROLS) (APPROXIMATELY 98 PERCENT OF
P/T PROCESS EMISSIONS IN METRIC TONNE CO2 EQUIVALENT), METRIC TONNE AND METRIC TONNE CO2 EQUIVALENT
Fluorinated GHG Name

2011

2012

2013

2014

2015

2016

Sum

%

Total,

tonne

tonne

Cumul
ative

2011

2012

2013

2014

2015

2016

%

Sum
Total,
tonne
CO2eq.

1,1,1,3,3,5,5,7,7,9,9,11,11-tridecafluoro2,4,6,8,10-pentaoxadodecan-12-oyl fluoride

0

0

0

0

1

0

1

0%

100%

HFC-227ca

0

0

1

0

0

0

1

0%

100%

2,3,3,3-Tetrafluoro-2(trifluoromethoxy)propionyl fluoride

1

1

0

0

0

0

1

0%

100%

Heptafluoropropyl trifluoromethyl ether

0

0

0

0

0

0

1

0%

100%

2-Butene, 2-chloro-1,1,1,3,4,4,4-heptafluoro

1

0

0

0

0

0

1

0%

100%

Trifluoroacetic acid

0

0

1

0

0

0

1

0%

1H-perfluorooctane

0

0

0

0

0

1

1

Unknown FC

0

0

0

0

0

0

1

[[Difluoro(trifluoromethoxy)methoxy]difluorom
ethoxy]difluoro-acetyl fluoride

0

0

0

0

0

1

Propanenitrile, 2,3,3,3-tetrafluoro-2(trifluoromethyl)-

0

0

0

0

0

Unknown Sulfonated FC

0

0

0

0

Perfluoro compounds, C5-18

0

0

0

C5F13N00

Perfluorotributyl amine

00C6F15N

0

C7F16O
C6F12

0

2,993

0

2,993

Cumul
ative

CO2eq.

%

0.0%

99.9%

0

0

0

1,120

2,727

0

0

0

3,846

0.0%

99.9%

1,141

1,176

0

0

0

0

2,317

0.0%

99.9%

1,299

1,004

3,103

0

1,143

2,086

8,635

0.0%

99.9%

1,380

0

0

0

0

0

1,380

0.0%

99.9%

100%

0

0

1,378

0

0

0

1,378

0.0%

99.9%

0%

100%

0

0

0

0

0

2,404

2,404

0.0%

99.9%

0%

100%

0

0

0

0

2,267

3,888

6,155

0.0%

99.9%

1

0%

100%

0

0

0

0

0

1,190

1,190

0.0%

99.9%

1

1

0%

100%

0

0

0

0

0

1,091

1,091

0.0%

99.9%

0

0

1

0%

100%

0

0

3,143

1,036

0

1,238

5,417

0.0%

100.0%

0

0

0

0

0%

100%

0

0

39

837

0

4,034

4,910

0.0%

100.0%

0

0

0

0

0

0%

100%

1,545

0

0

0

1,055

0

2,600

0.0%

100.0%

0

0

0

0

0

0%

100%

1,179

1,058

0

0

0

0

2,237

0.0%

100.0%

0

0

0

0

0

0

0%

100%

2,021

0

0

0

0

0

2,021

0.0%

100.0%

0

0

0

0

0

0

0

0%

100%

0

0

1,474

0

0

0

1,474

0.0%

100.0%

0

0

0

0

0

0

0

0%

100%

0

0

0

0

1,015

0

1,015

0.0%

100.0%

Perfluorobutyliodide

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

HFC-1132a; VF2

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

HFC-1141; VF

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

1,1,1,3,3,3-Hexafluropropane

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories

0

%
tonne

3.57

Volume 3: Industrial Processes and Product Use

TABLE 3A.1.2 (NEW) (CONTINUED)ACTUAL EMISSIONS FROM PRODUCTION AND TRANSFORMATION PROCESS REPORTED BY SPECIFIC FLUORINATED GHG UNDER SUBPART L OF THE GHGRP (CONSIDERING CONTROLS) (APPROXIMATELY 98 PERCENT OF
P/T PROCESS EMISSIONS IN METRIC TONNE CO2 EQUIVALENT), METRIC TONNE AND METRIC TONNE CO2 EQUIVALENT
Fluorinated GHG Name

2011

2012

2013

2014

2015

2016

Sum

%

Total,

tonne

tonne

Cumul
ative

2011

2012

2013

2014

2015

2016

%

Sum
Total,
tonne
CO2eq.

%
tonne

Cumul
ative

CO2eq.

%

1,2-Oxathiane, 3,3,4,4,5,5,6,6-octafluoro-, 2,2dioxide

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

2,2,3,3,4,4,-hexafluoro-4-(fluorosufonyl)butanoyl fluoride

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

2,3,3,3-Tetrafluoro-2(heptafluoropropoxy)propanoyl fluoride

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

Heptafluoropropyl trifluorovinyl ether

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

Hexafluoroacetone

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

HFC-236ea

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

Methyl perfluoro(5-methyl-4,7-dioxanon-8enoate)

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

Oxetane, 2,2,3,4,4-Pentafluro-3(trifluoromethyl)-

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

Pentafluoroethyl trifluorovinyl ether

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

Perfluoroisobutyric acid fluoride

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

PFC-1114; TFE

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

PFC-1216; Dyneon HFP

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

PMVE; HFE-216

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

Propanoyl fluoride, 2,2,3,3-tetrafluoro-

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

1,2-Oxathiane, 3,3,4,4,5,5,6,6-octafluoro-, 2,2dioxide

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

2,2,3,3,4,4,-hexafluoro-4-(fluorosufonyl)butanoyl fluoride

-

-

-

-

-

-

-

0%

100%

-

-

-

-

-

-

-

-

100.0%

1,263

1,237

1,285

988

946

765

6,484

7,316,491

7,481,451

8,011,806

5,352,488

4,634,366

3,746,556

36,543,158

TOTAL

a US EPA, 2017. Data extracted from US EPA Facility Level Information on Greenhouse Gases Tool (FLIGHT). Based on data reported to EPA by August 05, 2017 (freeze date). https://ghgdata.epa.gov/ghgp/main.do#

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TABLE 3A.1.3 (NEW)ACTUAL FLUORINATED GHG EMISSIONS FROM PRODUCTION AND TRANSFORMATION PROCESSES FROM SUBPART L OF THE GHGRP (CONSIDERING CONTROLS),BY GROUP (METRIC TONNE CO2 EQUIVALENT) A
Fluorinated GHG Group

2011

2012

2013

2014

2015

2016

Fully fluorinated GHGs

2,679,675

2,609,942

3,313,760

2,149,381

1,942,407

1,756,714

Saturated hydrofluorocarbons (HFCs) with 2 or fewer carbon-hydrogen bonds

4,068,950

4,350,171

4,065,235

2,684,590

2,198,462

1,380,406

Saturated HFCs with 3 or more carbon-hydrogen bonds

677,653

630,075

634,337

507,953

497,508

502,570

Saturated hydrofluoroethers (HFEs) and hydrochlorofluoroethers (HCFEs)
with 1 carbon-hydrogen bond

3,324

3,358

25,04842,61742,78197,454

Saturated HFEs and HCFEs with 2 carbon-hydrogen bonds

70

3

4

2

48

67

Saturated HFEs and HCFEs with 3 or more carbon-hydrogen bonds

3,741

4,130

4,743

3,777

4,124

5,289

Fluorinated formates

-

-

-

-

-

0

Fluorinated acetates, carbonofluoridates, and fluorinated alcohols other than
fluorotelomer alcohols

62

17

93

243

120

126

Unsaturated perfluorocarbons (PFCs), unsaturated HFCs, unsaturatedhydrochlorofluorocarbons (HCFCs), unsaturated halogenated ethers,
unsaturated halogenated esters, fluorinated aldehydes, and fluorinated ketones

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Fluorotelomer alcohols

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Fluorinated GHGs with carbon-iodine bond(s)Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysis

Excluded fromanalysisOther fluorinated GHGs

40,242

34,48539,55925,82627,114

69,038TOTAL

7,473,716

7,632,181

8,082,779

5,414,389

4,712,564

3,811,664

a Ibid EPA 2017.

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We reviewed four DE assumptions, along with the uncontrolled emissions implied by these assumptions, toensure that the default emission factor was as robust and accurate as possible. 16 These included:1.

A lower-bound assumption that assumed that the DE for each process was always equal to the lower
bound of the DE range reported for that process. This results in an absolute lower-bound estimate of
uncontrolled emissions. Uncontrolled emissions from any facility cannot fall below the level implied bythis assumption.

2.

An upper-bound assumption that assumed that the DE for each process was always equal to the upperbound of the DE range reported for that process. This results in an absolute upper-bound estimate of
uncontrolled emissions. 17 Uncontrolled emissions from any facility cannot fall above the level impliedby this assumption.

3.

An arithmetic mean assumption that assumed that the DE for each process was equal to the straightaverage of the upper and lower bound of the DE range reported for that process. This is expected to be
an unbiased estimator of uncontrolled emissions if a DE is equally likely to fall anywhere within therange and uncontrolled emissions are also equally likely to fall anywhere within the range (that is,
uncontrolled emissions across processes and facilities are not expected to be higher at one end of therange than the other).

4.

A geometric mean assumption that assumed that the DE for each process was equal to 1 minus thegeometric mean of the fractions emitted at the DE range bounds reported for that process. (In Excel
using MS Excel functions, this is summarized by the formula (1-GEOMEAN((1-LB),(1-UB)). This is
expected to be an unbiased estimator of uncontrolled emissions if a DE is equally likely to fall
anywhere within the range and uncontrolled emissions, across processes and facilities, growexponentially as the DE increases.

The emissions prior to control for production and transformation processes are calculated using Equation 3A.1.1.
EQUATION 3A.1.1 (NEW)EMISSIONS PRIOR TO CONTROL FOR PRODUCTION AND TRANSFORMATION PROCESSES

Emissions Prior to Control =( Post − Control emissions from process vents ) / (1 − DE ) 
+ Emissions from equipment leaks

Table 3A.1.4 provides the estimated pre-abatement emissions by fluorinated GHG group (in metric tonne CO2eq.)
when each DE assumption is used to estimate pre-abatement emissions.

d. Selection of Arithmetic Mean as Basis for Estimates.

As the basis for our best estimates of uncontrolled emissions, we considered both the arithmetic and geometricmeans of the DE ranges. Choosing the appropriate DE assumption is based on the distribution of the emissions
within each DE range. If the uncontrolled emissions are increasing exponentially across the range, thenapplication of the geometric mean is more appropriate. If the uncontrolled emissions are constant across therange, then application of the arithmetic mean is more appropriate. Exponentially rising uncontrolled emissions
would be consistent with a control strategy that selectively targeted the streams with the highest GWP-weighted
emissions. It is clear that facilities tend to prioritize the control of high GWP streams and that this is often thefirst consideration in determining whether a stream will be controlled. In addition to high GWP, however,facilities also include other considerations in their decisions regarding which streams to send to a destruction
device. Other considerations may include technical considerations, regulatory requirements, and safety concerns.
Technical considerations include things such as the distance from the process to the destruction device forrouting a vent to a control device, or the need to drop down the stream pressure prior to venting to a control
device. Some facilities will have the technical expertise to overcome these issues while others may not. Anotherconsideration is regulatory requirements or market forces that may affect whether a stream is controlled. In

16 As discussed in section A3.1.5 below, we also performed a Monte Carlo analysis to assess the uncertainty of the emission

factor estimate, including the uncertainty of the exact DE as well as other uncertainties.

17 This is unconditionally true for the first three DE ranges, but for the last one (>99 percent), we must choose a realistic

upper bound because using a value of 100 percent would result in infinite pre-abatement emissions. We chose 99.99
percent, but we could have chosen 99.9 or 99.999 percent instead, with a factor of 10 difference either way for the preabatement emissions in this DE range. We also used the 99.99 percent upper bound to calculate the arithmetic andgeometric means for the highest DE range.

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Chapter 3:Chemical Industry Emissions

addition, safety is a consideration. For example, there may be instances where the destruction device is down andnot operating, and for safety reasons a process that is mid-process may be vented directly to the atmosphere.
Table 3A.1.4 provides the controlled emissions (actual) in metric CO2eq., as well as the uncontrolled emissions
in metric tonne CO2eq. estimated using the lower bound of the DE range, the arithmetic mean of the DE range,
the geometric mean of the DE range, and the upper bound of the DE range. These emissions include the full setof emissions from production and transformation processes. Note that the lower-bound uncontrolled emissions
are approximately four times as large as the controlled emissions (though this varies by year). The estimates of
uncontrolled emissions under the various DE assumptions span a factor of almost 30: the arithmetic-mean
uncontrolled emissions are approximately twice as large as the lower-bound uncontrolled emissions, thegeometric-mean uncontrolled emissions are approximately two and a half times as large as the arithmetic-mean
uncontrolled emissions, and the upper-bound uncontrolled emissions are approximately seven times as large as
the geometric-mean uncontrolled emissions.
TABLE 3A.1.4 (NEW)ESTIMATED PRE-ABATEMENT FLUORINATED GHG EMISSIONS FROM PRODUCTION AND TRANSFORMATION PROCESSESFROM SUBPART L OF THE GHGRP, ALL DE ASSUMPTIONS (METRIC TONNE CO2 EQUIVALENT)DE Assumption

2011

2012

2013

2014

2015

2016

Sum Total,
tonne CO2eq.

Actualemissions

7,473,716

7,632,181

8,082,779

5,414,389

4,712,564

3,811,664

37,127,293

Lower boundDE emissions,pre-abatement

33,126,816

26,348,042

22,970,419 23,678,050

21,459,616

27,852,452

155,435,395

Arithmetic mean
DE emissions,pre-abatement

57,275,451

43,684,030

37,104,181 38,859,484

35,409,856

49,860,047

262,193,049

Geometric mean
DE emissions,pre-abatement

162,302,698

89,923,131

60,355,569 73,690,456

70,568,769 167,408,713

624,249,337

Upper bound DE
emissions, preabatement

1,275,608,396 541,882,779 256,555,587 400,139,115 407,755,113 1,441,071,577

4,323,012,567

One author compiled data on DEs achieved for one fluorochemical production process over several years, andthese data showed a geometric distribution. However, there was no way to be certain that the distribution for thissingle process applied to the hundreds of other processes whose emissions are reported under subpart L. Thus,
we selected the arithmetic mean, which assumes that uncontrolled emissions are flat as the DE increases, as thebasis for our estimates of uncontrolled emissions. For this reason, the detailed analysis below focuses on thearithmetic mean scenario, but summary information is provided for the other scenarios to show the sensitivity of
uncontrolled emissions to different DE assumptions. Table 3A.1.5 provides the uncontrolled emissions byfluorinated GHG group (in metric tonne CO2eq.) estimated using the arithmetic mean of the DE range. The
estimates in Table 3A.1.5 are used in section 3.1.4 to develop the profile of specific fluorinated GHGs emitted ina pre-abatement scenario.

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TABLE 3A.1.5 (NEW)ESTIMATED PRE-ABATEMENT FLUORINATED GHG EMISSIONS FROM PRODUCTION AND TRANSFORMATION PROCESSESFROM SUBPART L OF THE GHRP (USING ARITHMETIC MEAN OF DE RANGE), BY FLUORINATED GHG GROUP (METRICTONNE CO2 EQUIVALENT)
Fluorinated GHG Group

2011

2012

2013

2014

2015

2016

Fully fluorinated GHGs

42,739,622

29,929,077

23,858,516

27,730,456

24,770,670

39,481,096

Saturated hydrofluorocarbons(HFCs) with 2 or fewer carbonhydrogen bonds

11,830,986

12,109,647

11,616,289

9,633,496

9,313,549

8,442,867

Saturated HFCs with 3 or morecarbon-hydrogen bonds

2,436,833

1,452,855

1,426,863

1,257,906

1,073,521

1,340,253

Saturated hydrofluoroethers(HFEs) andhydrochlorofluoroethers(HCFEs) with 1 carbonhydrogen bond

23,903

11,91342,13898,246

68,548

155,945

Saturated HFEs and HCFEs with
2 carbon-hydrogen bonds

384

555

792

376

319

471

Saturated HFEs and HCFEs with
3 or more carbon-hydrogen
bonds

9,262

10,3689,135

16,09016,20033,356

Fluorinated formats

-

-

-

-

-

0

Fluorinated acetates,
carbonofluoridates, andfluorinated alcohols other than
fluorotelomer alcohols

70

23

96

243

973

829

Unsaturated perfluorocarbons(PFCs), unsaturated HFCs,
unsaturatedhydrochlorofluorocarbons(HCFCs), unsaturated
halogenated ethers, unsaturated
halogenated esters, fluorinatedaldehydes, and fluorinatedketones

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Fluorotelomer alcohols

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Fluorinated GHGs with carboniodine bond(s)Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

ExcludedfromanalysisOther fluorinated GHGs

234,391

169,593

150,352

122,671

166,076405,231

TOTAL

57,275,451

43,684,030

37,104,181

38,859,484

35,409,856

49,860,047

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Chapter 3:Chemical Industry Emissions

3A.1.2.4

Container Venting Emissions

Container venting, or container evacuation, is another source of emissions that is common to fluorinated gas
production facilities. Emissions from container venting occurred at 6 of the 16 facilities in the U.S. over
RY2011 through RY2016. It is anticipated that all container venting emissions are uncontrolled, so no DE
assumption is necessary. Table A3.1.6 provides actual GHG emissions for container venting in metric tonne
CO2eq., by individual facility. In later tables, container venting emissions have been included in the emission
values along with the emissions from production and transformation processes.
TABLE 3A.1.6 (NEW)ACTUAL EMISSIONS OF SPECIFIC FLUORINATED GHG FROM CONTAINER VENTING REPORTED UNDER SUBPART L OF THE
GHGRP, BY FACILITY (METRIC TONNE AND METRIC TONNE CO2 EQUIVALENT)
Tonne

Tonne CO2eq.

FacilityID

Facility name

2011

2012

2013

2014

2015

2016

2011

2012

2013

2014

2015

2016

526024

3M COMPANY

-

-

-

-

-

-

-

-

-

-

-

-

524391

3M CORDOVA

9

7

-

1

1

3

5275193M Cottage Grove
Center – Site

-

-

-

-

-

-

-

-

-

-

-

-

526434

ANDERSONDEVELOPMENTCOMPANY

-

-

-

-

-

-

-

-

-

-

-

-

526676

ARKEMA, INC.

16

18

15

6

9

10

522460Chemours - Corpus
Christi Plant

-

-

-

-

-

-

-

-

-

-

-

-

523728CHEMOURSCHAMBERS
WORKS

-

-

-

-

-

-

-

-

-

-

-

-

523649CHEMOURS
COMPANY FAYETTEVILLE
WORKS

14

3

6

6

8

8

525649Chemours EL
DORADO

-

-

-

-

-

-

-

-

-

-

-

-

526198Chemours
LOUISVILLE
WORKS

-

-

-

-

-

-

-

-

-

-

-

-

523005Chemours
WASHINGTON
WORKS

-

-

-

-

-

-

-

-

-

-

-

-

527234DAIKINAMERICA INC.

-

-

-

-

-

-

-

-

-

-

-

-

522053

HONEYWELL
INTERNATIONAL
INC - BATON
ROUGE PLANT

-

-

-

-

-

-

-

-

-

-

-

-

522051HONEYWELL
INTERNATIONAL
INC - GEISMARCOMPLEX

-

-

-

-

1

-

-

-

-

-

1,494

-

522956

MEXICHEM
FLUOR INC.

0

-

-

-

-

-

1

-

-

-

-

-

527776

Versum Materials
US, LLC

-

-

-

-

1

-

-

-

-

-

5 ,081

-

TOTAL

39

28

21

14

20

20

80,726 65,897-

11,934 12,237 20,865

41,697 61,596 38,772 16,071 23,785 25,096

141,001 29,189 56,284 60,283 72,439 73,468

263,425 156,683 95,056 88,287 115,036 119,429

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3A.1.2.5
Production and Transformation Quantities Reported Under
Subpart OO, Suppliers of Greenhouse Gases
Facilities that produce and transform fluorinated GHGs report the production and transformation quantities to the
GHGRP under subpart OO. These data are considered confidential business information on an individual
facility basis, and are therefore not publicly available. Table A3.1.7 provides total aggregate fluorinated GHG
data on a metric tonne basis for production and transformation processes for subpart OO.
TABLE 3A.1.7 (NEW)PRODUCTION AND TRANSFORMATION QUANTITIES REPORTED UNDER SUBPART OO OF THE GHGRP (METRIC TONNE)
Quantity

2011

2012

2013

2014

2015

2016

Production and Transformation of Fluorinated Gas

291,000

276,000

302,000

307,000

278,000

315,000

3A.1.3 EMISSION FACTOR DEVELOPMENT FOR FLUORINATED GHGS
3A.1.3.1
Estimated pre-abatement emission in metric tonne for Average
Emissions Factor Analysis
The average emission factor was developed in terms of metric tonne of emissions. To support this analysis,
calculations that estimate the pre-abatement emissions of fluorinated GHG on a metric ton basis must be
performed.
The calculations that result in the emissions shown in Table 3A.1.5 above yield GWP-weighted, estimated preabatement emissions in metric tonne of CO2eq. for each production or transformation process. To estimate
emissions in metric tonne prior to control, we need a way to estimate the weighted average GWP for eachfacility and reporting year, to account for the fact that fluorinated GHGs with different GWPs may be controlled
at different levels. That is, the GWP distribution of actual emissions may not match the GWP distribution of preabatement emissions. We can then divide the emissions in metric tonne of CO2eq. by the corresponding GWP tocalculate the emissions in metric tons. (Recall that the US EPA receives DE range information on a processbasis, but does not receive data on individual fluorinated GHGs by process.) The steps we followed to derive the
GWPs are outlined below.
a.
Weighted-average GWP of controlled emissions. We first calculated the weighted-average GWP of thecontrolled emissions for each facility and year by dividing (1) the total actual emissions reported by each facility
for all production and transformation processes in metric tonne of CO2eq. by (2) the emissions calculated foreach facility in metric tons. 18 However, we cannot necessarily apply this weighted average GWP to theestimated pre-abatement emissions calculated for that facility and year. Because facilities may control emissions
with different GWPs to varying extents, the average GWP of the pre-abatement emissions may be different fromthe average GWP of the actual emissions.
b.
Factor to Calculate Weighted-average GWP for Estimated Pre-abatement Emissions. To account fordifferent control levels that may be applied to fluorinated GHGs having different GWPs, we used the processlevel reporting of actual emissions by fluorinated GHG group in metric tonne of CO2eq., as well as our
calculations of pre-abatement emissions based on these numbers. Where processes that emit higher-GWP
fluorinated GHG groups are controlled to a greater extent than processes that emit lower-GWP fluorinated GHG
groups, the calculated emissions of the former will grow more than the calculated emissions of the latter as one
moves from the controlled to the pre-abatement scenario. This signal appears in the pre-abatement emissions
calculated under the DE assumption in section A3.1.2.3.c above. We can use this signal, along with assumptions
about the average GWP of each fluorinated GHG group, to estimate how the weighted-average GWP haschanged from the controlled scenario. Using this approach, we developed a ratio of the weighted-average GWPof the estimated pre-abatement emissions to the weighted-average GWP of the actual emissions for each facility
and reporting year, and multiplied this ratio by the GWP of the controlled emissions calculated in Step a.
Specifically, we performed the following calculations:18 Emissions in metric tonne are calculated as the sum of the emissions that are reported by specific fluorinated GHG in

metric tonne (reported in metric tonne of fluorinated GHG), plus the estimated emissions of fluorinated GHGs whose
emissions are reported by fluorinated GHG group in metric tonne CO2eq., after conversion to metric tonne. For the latter,
the GWP-weighted emissions are divided by the average GWP for each group to calculate emissions in metric tonne.

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Chapter 3:Chemical Industry Emissions

1.

For each facility and reporting year, we assumed that the emissions of each fluorinated GHG group had theaverage GWP of that group and divided the metric tonne of CO2eq. emissions for that group by theweighted-average GWP to obtain estimates of emissions in metric tonne. We then totaled both metric tonne
CO2eq. and metric tonne for all groups, and divided the first by the second to get a weighted-average GWP(uncontrolled) for that facility and year.

2.

Then we divided the weighted-average GWP (pre-abatement) for each facility and reporting year by the
GWP for the actual controlled scenario for that facility and year to obtain a set of ratios.

3.

Finally, we multiplied these ratios by the weighted-average GWPs (for each facility and year) that we
calculated for the controlled (actual) scenario in Step a.

The estimated pre-abatement fluorinated GHG emissions, in metric tonne, for production and transformation
processes based on the adjusted GWP are provided for the arithmetic mean DE assumption, by individual facility
in Table 3A.1.8.
TABLE 3A.1.8 (NEW)ESTIMATED PRE-ABATEMENT FLUORINATED GHG EMISSIONS FROM PRODUCTION AND TRANSFORMATION PROCESSES PLUS
CONTAINER VENTING FROM SUBPART L OF THE GHGRP (USING ARITHMETIC MEAN OF DE RANGE) BY FACILITY (METRICTONNE)
FACILITY NAME

2011

2012

2013

2014

2015

2016

3M COMPANY

2

4

5

6

2

3

3M CORDOVA

4,348

3,219

2,493

3,005

2,730

4,442

3M Cottage Grove Center – Site

5

7

8

3

3

3

ANDERSON DEVELOPMENTCOMPANY99

4

ARKEMA, INC.

1,018

1,385

1,232

1,075

1,198

1,411

Chemours - Corpus Christi Plant

27

40

35

13

9

35

CHEMOURS CHAMBERS WORKS

75

82

102

73

62

34

CHEMOURS COMPANY FAYETTEVILLE WORKS

76

68

71

72

109

119

Chemours EL DORADO

22

21

22

22

25

21

Chemours LOUISVILLE WORKS

19

9

12

10

Chemours WASHINGTON WORKS

297

57

34

29

65

386

DAIKIN AMERICA INC.

44

37

39

44

46

49

HONEYWELL INTERNATIONAL INC BATON ROUGE PLANT

70

76

78

50

55

41

HONEYWELL INTERNATIONAL INC GEISMAR COMPLEX

2,547

1,119

1,247

1,243

1,298

430

MEXICHEM FLUOR INC.

42

42

7

7

10

9

Versum Materials US, LLC

39

38

27

26

29

26

TOTAL

8,638

6,211

5,415

5,680

5,641

7,009

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3A.1.3.2

Metric of the Emission Factor

The goal of our analysis was to develop an emission factor in terms of metric tonne of fluorinated GHG
emissions divided by metric tonne of fluorinated gas produced and transformed (Total emissions in metric tonne/ production and transformation quantity produced, in metric tonne). This is because any GWPs or other metrics
used to express fluorinated gas emissions relative to CO2 may go out of date after publication of the emission
factor, potentially reducing the applicability of the factor. 19
We developed an unweighted average EF (i.e., average across facilities of each facility’s emission factor, wherethat factor equals the facility’s emissions divided by the sum of that facility’s production and transformation).
We also examined the standard deviation of the facility-specific emission factors. For an average, each facility isweighted equally and facilities with comparatively larger or smaller EF values influence the average value even
if the quantities that they produce and/or transform are small. The average emission factor, based on an average,
was calculated to be 0.04 metric tonne fluorinated GHG emissions per metric tonne quantity produced andtransformed.
TABLE 3A.1.9 (NEW)DEFAULT EMISSION FACTOR FOR FLUORINATED PRODUCTION
2011

2012

2013

2014

2015

2016

AverageAcrossYears

EF based on Arithmetic Mean,
metric tonne/ metric tonne

0.05

0.04

0.03

0.04

0.03

0.04

0.04

Standard Deviation

0.1

0.1

0.07

0.1

0.08

0.1

Relative Standard Deviation

200%

250%

230%

250%

270%

250%

95% confidence interval

390%

490%

450%

490%

520%

490%

470%

3A.1.4 ANALYSIS OF COMMON FLUORINATED GHGS EMITTED FROMFLUOROCHEMICAL PROCESSESThe emission factor in Table A3.1.9 is expressed in terms of metric tonne emitted per metric tonne produced ortransformed. To be of use for an emissions inventory, knowledge of, or assumptions regarding, the fluorinatedGHGs emitted is necessary. This section summarizes the data and approach used for identifying the most emitted
fluorinated GHGs from fluorochemical production based on the data reported by facilities to the U.S. GHGRP.

3A.1.4.1
Analysis

Develop Ratios for Most Emitted Fluorinated GHG Emissions

To identify the most emitted fluorinated GHGs, the analysis begins with comparing the actual emissions byfluorinated GHG group (summarized in Table A3.1.3) with the estimated pre-abatement emissions (the estimatedpre-abatement emissions are shown in Table A3.1.5). The DE range is provided for each production andtransformation process but is not provided for individual specific fluorinated GHGs. To calculate these preabatement emissions, we need a way to estimate the unweighted metric tonne for each fluorinated GHG groupand reporting year. The calculations in Table A3.1.5 yield GWP-weighted, pre-abatement emissions in metrictonne CO2eq. for each production or transformation process. A ratio of the pre-abatement emissions in metrictonne CO2eq. compared to the actual emissions in metric tonne CO2eq. can be developed for each fluorinated
GHG group and reporting year. These ratios can then be applied to the actual emissions of specific fluorinated
GHG in metric tonne CO2eq. to appropriately estimate the pre-abatement level of specific fluorinated GHG in
metric tonne. (Recall that the US EPA does not receive data on unweighted emissions, metric tonne, ofindividual fluorinated GHGs by process.) The ratios of pre-abatement metric tonne CO2eq. compared to actual
metric tonne CO2eq. are provided in Table A3.1.10.

A3.1.4.2
Pre-abatement Emissions in metric tonne CO 2 eq. and metric tonne
for Specific Fluorinated GHGs, for Production and Transformation Processes,
and Container Venting
19 We also reviewed factors using GWP-weighted emissions and production/transformation quantities because they provided

insight into how the GWPs of fluorinated GHGs emitted relate to the GWPs of fluorinated gases produced across facilities.

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Chapter 3:Chemical Industry Emissions

Applying the ratios in Table A3.1.10 to the Table A3.1.2 actual emissions provides the pre-abatement emissions
by fluorinated GHG (in metric tonne CO2eq.). The ratios were multiplied by the specific fluorinated GHG, basedon its fluorinated GHG group, for each reporting year. The estimated pre-abatement emissions by specificfluorinated GHG, in metric tonne CO2eq. and metric tonne, are provided in Table A3.1.11 for production andtransformation processes, along with the container venting emissions.

A3.1.4.3

Representative Fluorinated GHG Profile

The most commonly emitted fluorinated GHGs on a pre-abatement emissions basis can be determined from thedata set. The most common fluorinated GHGs, by metric tonne and by metric tonne CO2eq., are shown in Table
A3.1.12. Those fluorinated GHGs that do not have GWPs in any IPCC Assessment Report (e.g., the Fifth
Assessment Report) have been dropped from the list (i.e., hexafluoropropylene oxide, andoctafluorotetrahydrofuran). The analysis shows the representative chemical composition in metric tonne for the
top 10 fluorinated GHGs.
TABLE 3A.1.10 (NEW)RATIOS OF ESTIMATED PRE-ABATEMENT EMISSIONS IN METRIC TONNE CO2 EQUIVALENT (USING ARITHMETIC MEAN OF DE
RANGE) TO ACTUAL EMISSIONS IN METRIC TONNE OF CO2 EQUIVALENT
Fluorinated GHG Group

2011

2012

2013

2014

2015

2016

Fully fluorinated GHGs

15.9

11.5

7.2

12.9

12.8

22.5

Saturated hydrofluorocarbons (HFCs) with 2 or
fewer carbon-hydrogen bonds

2.9

2.8

2.9

3.6

4.2

6.1

Saturated HFCs with 3 or more carbonhydrogen bonds

3.6

2.3

2.2

2.5

2.2

2.7

Saturated hydrofluoroethers (HFEs) andhydrochlorofluoroethers (HCFEs) with 1
carbon-hydrogen bond

7.2

3.5

1.7

2.3

1.6

1.6

Saturated HFEs and HCFEs with 2 carbonhydrogen bonds

5.5

191.2

193.2

198.0

6.7

7.0

Saturated HFEs and HCFEs with 3 or morecarbon-hydrogen bonds

2.5

2.5

1.9

4.3

3.9

6.3
1.6

Fluorinated formats
Fluorinated acetates, carbonofluoridates, andfluorinated alcohols other than fluorotelomer
alcohols

1.1

1.4

1.0

1.0

8.1

6.6

Unsaturated perfluorocarbons (PFCs),
unsaturated HFCs, unsaturatedhydrochlorofluorocarbons (HCFCs), unsaturated
halogenated ethers, unsaturated halogenatedesters, fluorinated aldehydes, and fluorinatedketones

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Fluorotelomer alcohols

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Fluorinated GHGs with carbon-iodine bond(s)Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

Excludedfromanalysis

5.8

4.9

3.8

4.7

6.1

5.9

Other fluorinated GHGs

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TABLE 3A.1.11 (NEW)ESTIMATED PRE-ABATEMENT FLUORINATED GHG EMISSIONS FROM PRODUCTION PROCESSES, TRANSFORMATION PROCESSES, AND CONTAINER VENTING FROM SUBPART L OF THE GHGRP (USINGARITHMETIC MEAN OF DE RANGE), BY SPECIFIC FLUORINATED GHG (METRIC TONNE CO2 EQUIVALENT AND METRIC TONNE)
Fluorinated GHG Name

2011

2012

2013

2014

2015

2016

Sum
Total,
tonne

2011

2012

2013

2014

2015

2016

Sum Total,
tonne
CO2eq.

PFC-14 (Perfluoromethane)

961

882

417

605

581

1,224

4,670

7,099,740

6,517,927

3,082,715

4,471,865

4,293,330

9,047,657

34,513,233

HFC-134a

780

621

599

731

963

904

4,598

1,115,275

888,437

857,188

1,045,203

1,377,357

1,292,344

6,575,805

Perfluorocyclobutane

846

404

188

372

359

1,169

3,338

8,717,609

4,161,124

1,932,044

3,829,822

3,700,681

12,038,028

34,379,308

HFC-32

452

459

436

418

551

556

2,872

305,085309,916

294,328

281,876

371,685

375,472

1,938,362

HFC-125

447

428

450

543

579

387

2,834

1,565,149

1,496,910

1,574,237

1,901,966

2,025,422

1,355,484

9,919,168

HFC-23

556

596

567

403

341

322

2,784

8,227,363

8,814,039

8,386,194

5,960,713

5,047,891

4,763,628

41,199,828

HFC-143a

492

299

290

249

201

274

1,805

2,199,566

1,337,071

1,295,696

1,111,496

899,663

1,223,588

8,067,080

Nitrogen trifluoride

493

322

141

204

194

286

1,639

8,472,427

5,534,029

2,420,335

3,510,222

3,331,771

4,921,716

28,190,500

Hexafluoropropylene oxide

197

201

143

260

305

411

1,517

1,969,139

2,005,481

1,427,557

2,604,466

3,054,522

4,109,247

15,170,411

PFC-116 (Perfluoroethane)

327

232

287

219

297

40

1,402

3,991,281

2,827,549

3,498,551

2,674,161

3,625,619

484,819

17,101,979

Octafluorotetrahydrofuran

301

290

285

299

72

108

1,355

3,005,532

2,901,350

2,848,074

2,993,494

715,725

1,084,733

13,548,907

Pentafluoro(trifluoromethyl)-cyclopropane

164

95

74

145

245

343

1,065

1,640,970

945,229

743,174

1,445,947

2,449,359

3,429,930

10,654,610

PFC-218 (Perfluoropropane)

202

89

346

211

42

63

953

1,785,524

783,260

3,058,038

1,859,967

373,114557,7038,417,605

PFC-5-1-14 (Perfluorohexane, FC 72)

187

94

57

132

162

135

769

1,741,556

877,250532,641

1,227,637

1,508,328

1,260,091

7,147,504

HFC-245fa

173

112

109

124

90

110

718

178,341

115,212112,576

127,561

93,150112,998

739,839

HFC-227ea

76

70

100

85

108

138

578

245,039

226,497

321,319274,773

347,144444,859

1,859,631

Trifluoromethyl sulphur pentafluoride

123

108

135

67

34

38

505

2,176,556

1,906,677

2,394,848

1,187,441

607,481668,577

8,941,579

HFE-449sl, (HFE-7100) Isomer blend

27

28

23

39

34

68

219

7,899

8,194

6,890

11,646

10,205

20,15464,987

PFC-3-1-10 (Perfluorobutane)

32

17

44

34

13

48

188

284,753

153,082

392,867

296,961

116,592

422,942

1,667,196

Perfluorodiethyl ether

27

34

15

18

21

36

151

267,613337,690

154,228

175,707

209,907364,894

1,510,039

HFC-152a

32

21

27

0

0

57

137

3,915

2,656

3,355

0

0

7,023

16,949PFC-4-1-12 (Perfluoropentane)

33

10

7

8

22

33

114

302,372

94,04365,17976,544

199,003306,266

1,043,407

Sulphur hexafluoride

20

13

23

38

13

6

113

462,400

294,817529,256

864,085295,614132,818

2,578,990

2H-perfluoro(5-methyl-3,6-dioxanonane)

23

22

12

8

14

32

111

45,291

44,61623,27916,442

28,19864,653

222,479

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TABLE 3A.1.11 (NEW) (CONTINUED)
ESTIMATED PRE-ABATEMENT FLUORINATED GHG EMISSIONS FROM PRODUCTION PROCESSES, TRANSFORMATION PROCESSES, AND CONTAINER VENTING FROM SUBPART L OF THE GHGRP (USINGARITHMETIC MEAN OF DE RANGE), BY SPECIFIC FLUORINATED GHG (METRIC TONNE AND METRIC TONNE CO2 EQUIVALENT)
Fluorinated GHG Name

2011

2012

2013

2014

2015

2016

Sum
Total,
tonne

Trifluoromethanesulfonyl fluoride

19

21

23

18

Pentafluoro(trifluoromethoxy)-ethane

31

12

21

13

Hexafluorooxetane

22

11

25

1,1,1,2,2,3,3-Heptafluoro-3-(1,2,2,2-tetrafluoroethoxy)propane
Perfluorobutanesulfonyl fluoride

3

2

7

2011

2012

10

8

99

38,16441,3087

11

96307,788

123,664

8

9

14

89

222,031

107,999

6

15

10

24

61

21,710

4

4

4

8

30

57

14,158

2013

2014

2015

2016

Sum Total,
tonne
CO2eq.

46,44635,632

212,517130,809

19,053

16,439197,043

73,289108,866

956,934

253,398

84,90590,084

135,633

894,051

11,216

41,87598,125

67,150155,716

395,791

8,234

7,949

8,739

16,27959,609114,969

HFC-236fa

7

9

14

10

8

9

57

64,40992,657

136,907102,260

76,64790,648563,528

PFC-6-1-12

18

15

1

2

4

0

39

141,418

115,806

7,764

14,32628,302

0

307,616

2,2,3,3,4-Pentafluoro-4-(trifluoromethyl)-oxetane

5

10

12

5

2

2

36

49,625

100,763

117,861

47,284

19,511

22,941

357,986

Carbonyl fluoride

9

4

3

4

5

7

32

17,338

8,230

5,092

8,564

9,703

14,62963,556

Trifluoroacetyl Fluoride

7

4

3

4

5

6

28

14,520

8,132

5,089

7,778

10,115

11,091

56,727

Perfluoro-2-(2-Fluorosulfonylethoxy) Propyl Vinyl
Ether
Perfluoropropionyl fluoride

0

0

0

0

7

17

23

0

0

0

0

13,27633,186

46,462

6

4

4

3

5

0

22

11,228

8,170

8,592

5,117

9,915

0

43,022

HFC-43-10mee

3

3

3

3

0

6

17

4,819

4,186

4,780

4,172

0

9,354

27,311

isobutyryl fluoride

14

0

0

0

0

0

14

27,191

0

0

0

0

0

27,191

Unknown FC

0

0

0

0

3

9

12

0

0

0

0

28,91087,380116,291

Heptafluoropropyl Trifluoromethyl Ether

2

1

2

0

1

5

12

20,717

11,513

22,3410

14,57646,882116,029

Perfluro compounds, C5-18

0

0

0

1

0

9

10

0

0

281

10,799090,662

101,741

1,1,1,3,3,5,5,7,7,9,9,11,11-tridecafluoro-2,4,6,8,10pentaoxadodecan-12-oyl fluoride
HFC-365mfc

0

0

0

0

9

0

9

0

0

0

0

18,330018,330

0

0

7

0

0

0

7

0

0

5,894

0

0

0

5,894

Unknown Sulfonated FC

0

0

2

1

0

3

6

0

0

22,62913,366027,82363,8182,3,3,3-Tetrafluoro-2-(trifluoromethoxy)propionyl
fluoride
HFC-227ca

3

3

0

0

0

0

6

6,643

5,785

0

0

0

0

12,429

0

1

3

0

0

0

4

0

3,117

7,792

0

0

12

10,921

2-Butene, 2-chloro-1,1,1,3,4,4,4-heptafluoro

4

0

0

0

0

0

4

8,038

0

0

0

0

0

8,038

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TABLE 3A.1.11 (NEW) (CONTINUED)
ESTIMATED PRE-ABATEMENT FLUORINATED GHG EMISSIONS FROM PRODUCTION PROCESSES, TRANSFORMATION PROCESSES, AND CONTAINER VENTING FROM SUBPART L OF THE GHGRP (USINGARITHMETIC MEAN OF DE RANGE), BY SPECIFIC FLUORINATED GHG (METRIC TONNE AND METRIC TONNE CO2 EQUIVALENT)
Fluorinated GHG Name

2011

2012

2013

2014

2015

2016

Sum
Total,
tonne

2011

2012

2013

2014

1H-perfluorooctane

0

0

0

0

0

4

C5F13N

2

0

0

0

1

0

4

0

0

0

4

24,6340

0[[Difluoro(trifluoromethoxy)methoxy] difluoromethoxy]
difluoro-acetyl fluoride

0

0

0

0

0

3

3

0

0

C6F15N3000

Propanenitrile, 2,3,3,3-tetrafluoro-2-(trifluoromethyl)-

0

0

0

0

0

0

3

32,22703

3

0

Perfluorotributyl amine

2

1

0

Trifluoroacetic Acid

0

0

3

0

0

0

3

18,802

0

0

0

3

0

C6F12

0

0

0

0

1

0

1

C7F16O02,3,3,3-Tetrafluoro-2-(heptafluoropropoxy)propanoyl
fluoride

0

0

1

0

0

0

0

0

0

0

0

Perfluroisobutyric acid fluoride

0

0

0

0

0

1,1,1,3,3,3-hexafluoropropane

0

0

0

0

2,2,3,3,4,4,-hexafluoro-4-(fluorosufonyl)-butanoyl
fluoride

0

0

0

0

Oxetane, 2,2,3,4,4-Pentafluoro-3-(trifluoromethyl)-

0

0

0

1,2-Oxathiane, 3,3,4,4,5,5,6,6-octafluoro-, 2,2-dioxide

00Propanoyl fluoride, 2,2,3,3-tetrafluoro-00

HFC-236ea

0

TOTAL

7,137

3.70

2015

2016

Sum Total,
tonne
CO2eq.

00

14,703

14,7030

13,4540

38,088

0

0

0

6,987

6,987

0

0

0

0

0

32,227

0

0

0

0

6,406

6,406

12,132000030,934

0

5,239

0

0

0

5,239

0

0

0

0

12,9440

12,9441

0

0

10,61300010,613

1

0

0

0

0

741

466

1,207

0

0

0

0

0

0

0

442

442

0

0

0

0

0

0

0

0

91

91

0

0

0

0

0

0

0

0

39

39

0

0

0

0

0

0

0

0

0

156

156

0

0

0

0

0

0

0

0

0

0

6

6

0

0

0

0

0

0

0

0

0

0

5

5

0

0

0

0

0

0

0

0

0

0

0

3

3

5,551

4,914

5,303

5,338

6,958

35,20256,855,857

43,245,968

36,877,626

38,521,874

35,204,040

49,429,797

260,135,162

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Chapter 3:Chemical Industry Emissions

TABLE 3A.1.12 (NEW)TOP-10 EMITTED SPECIFIC FLUORINATED GHG, FROM PRODUCTION PROCESSES, TRANSFORMATION PROCESSES, AND
CONTAINER VENTING FROM SUBPART L OF THE GHGRP (USING ARITHMETIC MEAN OF DE RANGE ENDPOINTS)A
Fluorinated GHG Name

Sum total,
tonne

Percent

PFC-14 (Perfluoromethane)

4,670

18%

Fully fluorinated GHGs

4,598

18%

Saturated HFCs with 2 or fewer carbonhydrogen bonds

3,338

13%

Fully fluorinated GHGs

2,872

11%

Saturated HFCs with 2 or fewer carbonhydrogen bonds

2,834

11%

Saturated HFCs with 2 or fewer carbonhydrogen bonds

2,784

11%

Saturated HFCs with 2 or fewer carbonhydrogen bonds

1,805

7%

Saturated HFCs with 3 or more carbonhydrogen bonds

Nitrogen trifluorideaa

Fully fluorinated GHGs

Hexafluoropropylene oxidebb

Fully fluorinated GHGs

PFC-116 (Perfluoroethane)

1,402

5%

Fully fluorinated GHGs

Octafluorotetrahydrofuranbb

Fully fluorinated GHGs

Pentafluoro(trifluoromethyl)cyclopropanebb

PFC-218 (Perfluoropropane)

953

4%

Fully fluorinated GHGs

PFC-5-1-14 (Perfluorohexane, FC 72)

769

3%

Fully fluorinated GHGs

HFC-134a
Perfluorocyclobutane
HFC-32
HFC-125
HFC-23
HFC-143a

GHG Group

Fully fluorinated GHGs

Due to rounding, the sum of individual items will not equal 100%.
The 2019 Refinement includes separate emission factors specifically for NF3 production. As approximately 92 percent of NF3 emissions arefrom intended NF3 production, and NF3 is not commonly emitted from the production of other fluorochemicals, NF3 has been dropped fromthe analysis for representative composition.
abThese fluorinated GHGs that do not have GWPs in any IPCC Assessment Report (e.g., the Fifth Assessment Report) have been dropped
from the analysis for representative composition.

3A.1.5 UNCERTAINTY ANALYSIS OF AVERAGE EMISSION FACTOR
In addition to examining the sensitivity of calculated uncontrolled (i.e., pre-abatement) emissions to various
assumptions regarding the DE, we performed a Monte Carlo analysis to comprehensively assess the uncertaintyof the emission factor, given the uncertainty of the DE as well as other sources of uncertainty. The uncertainty inthe estimated pre-abatement emission in units of metric tonne CO2eq. is based on the wide ranges of the DE. The
uncertainty in the pre-abatement emission estimates in terms of metric tonne of fluorinated GHG is based on the
combination of the uncertainty in the DE and the uncertainty in the average GWP of the specific fluorinatedGHGs in the pre-abatement scenario. With respect to the DEs, we used the following assumed distribution.
TABLE 3A.1.13 (NEW)DISTRIBUTION ASSUMPTIONS FOR THE DE RANGESDE ranges

Distribution Assumptions≥0% to <75%

Half of the values are 0%; half of the values flat distribution between 0 and 74.9%≥75% to <95%

Flat distribution between 75 and 94.9%≥95% to <99%Flat distribution between 95 and 98.9%≥99%

Triangular distribution between 99 and 99.99% with mode at 99%

Because we expected that a significant number of reporters using the ≥0 to <75 percent range were uncontrolled,
we assumed a distribution function that assigns half of the distribution function to 0 percent DE.

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For estimating the uncertainty in the GWP, we evaluated the data for emissions by specific fluorinated GHG
compound (in metric tonne of specific GHG) that was reported for the facility as a whole. We developed
different GWP distributions for each facility and fluorinated GHG group combination based on the data reported
for a given facility. If only one specific fluorinated GHG compound was reported for a given facility within afluorinated GHG group (or if all of the specific GHGs reported by the facility were identical), the GWP of thatcompound was used directly (no uncertainty). If multiple specific fluorinated GHG compounds with different
GWPs were reported within a fluorinated GHG group for a given facility, we calculated the weighted average
GWP for that group based on the specific fluorinated GHG’s GWP and direct mass emissions reported by thatfacility. The weighted average GWP across all reporting years was used as the central tendency value and theweighted average for individual years was used to assess the range of the distribution function for the uncertainty
analysis. In some cases, the emissions for specific fluorinated GHG compounds in a group did not exceed theseparate reporting threshold (1,000 metric tonne CO2eq.) of subpart L, and only the metric tonne CO2eq.
emissions for the fluorinated GHG group were reported at the facility level. In this case, the individual GWPs for
all compounds listed within that fluorinated GHG group was used as the distribution function, and a random
GWP was selected from those values. When we first utilized this approach, the very low-GWP fluorinated GHG
groups (i.e., those groups whose members had GWPs near or below 1) dominated the estimated pre-abatement
fluorinated GHG emissions (in direct mass terms), which led to huge uncertainties in the mass emission rates forcompounds that had a negligible impact on emissions in terms of CO2eq. Consequently, we excluded the verylow-GWP fluorinated GHG groups’ emissions when estimating the mass of fluorinated GHG compoundemissions for developing the proposed emissions factor. For similar reasons, we used a lower GWP of 0.5 for the
fluorinated acetates, carbonofluoridates, and fluorinated alcohols other than fluorotelomer alcohols group, rather
than 0.05 value for 4,4,4-trifluorbutan-1-ol (CAS No. 461-18-7). It was assumed that, even if this compound was
the primary pollutant emitted from this group, small amounts of other compounds from this group would also
likely be emitted and that the value of 0.5 was a reasonable lower bound for this group.
Calculations of the pre-abatement emissions (in both metric tonne CO2eq. and in metric tonne of fluorinated
GHG group) were made using the process level emissions reported under subpart L. A Monte Carlo analysis
using 10,000 random realizations was used to estimate the average and 95th percentile confidence intervals forthe emissions. We assumed the uncertainty in the reported production quantities were negligible relative to theuncertainties in the uncontrolled emissions.
The average annual estimated pre-abatement emissions in metric tonne CO2eq. from the Monte Carlo analysis
compares reasonably well with but are slightly lower than the pre-abatement emissions estimates using thearithmetic mean DE assumption for the range. This is because the lowest and highest DE ranges were skewed
towards the lower DE values in the Monte Carlo analysis. The total estimated pre-abatement emissions in metrictonne of fluorinated GHG compounds from the Monte Carlo analysis (when excluding the low GWP groups) had
similar uncertainty ranges as the total estimated pre-abatement emissions in CO2e (which are based only on
uncertainty of the DE) for most facilities. A few facilities that had reported generic emissions of the fluorinatedacetates, carbonofluoridates, and fluorinated alcohols other than fluorotelomer alcohols group had much higher
uncertainty in their mass emissions than in their CO2e emissions due to the variability and uncertainty associatedwith the GWP.
The uncertainty in the average emission factor across all of the reporting facilities (i.e., the 95-percent
confidence interval around the sample mean), including the uncertainties in both the DE and in the GWP of theemitted gases, was 20 percent. In summary, these sources of uncertainty are mitigated by the large number ofdata points in the analysis, which come from the large number of processes and significant number of years
covered. Thus, the errors related to the DE estimated for each individual process and to the mix of gases emitted
tend to balance out, and the aggregate uncertainty is reduced.
It is important to note that the uncertainty in the emission factor for any single facility is much larger than this,and is dictated by the fact that true pre-abatement emission rates naturally vary from facility to facility dependingon the fluorochemicals produced and the processes used to make them. This variability appears in the U.S. EPA
data as differences in the estimated pre-abatement emission factors across facilities, differences that persist overthe entire time series. The year-to-year variability seen in the estimated pre-abatement emission factor for any
one facility is generally much smaller than this facility-to-facility variability. The uncertainty shown in Table
3A.1.9 reflects this variation among facilities. The 95 percent confidence interval (calculated based on therelative standard deviation among the facilities’ emission factors) is ±470 percent. Because there cannot be anegative emission factor on the low side, a value of 0.001 was selected as the lower uncertainty bound, as it isrepresentative of lower emission factor values seen in the data set. This results in an uncertainty range for the
Tier 1 default emission factor of 0.001 to 0.2.
As noted in section 3A.1.2 above, the selected EF is based on the straight average analysis. The average EF
based on the straight average is similar to the EF based on the Monte Carlo analysis. The overall EF that resultsfrom other assumptions, such as use of a weighted average or use of the geometric mean, are also provided inTable 3A.1.14 to provide additional context.

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Chapter 3:Chemical Industry Emissions

TABLE 3A.1.14 (NEW)COMPARISON OF EMISSION FACTOR VALUES IN PARALLEL ANALYSES
Selected EF

EF value, metric tonne/metric tonne

Arithmetic Mean DE assumption, straight average

0.04

Other EF Bases
Arithmetic Mean DE assumption, weighted average

0.02

Geometric Mean DE assumption, weighted average

0.05

Monte Carlo

0.04

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References
SECTIONS 3.2 - 3.8
References newly cited in the 2019 Refinement

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EFMA (2000b). European Fertilizer Manufacturers’ Association, Best Available Techniques for Pollution
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SECTION 3.10.1
References newly cited in the 2019 Refinement

Irving, W.N. & Branscome, M. (1999) HFC-23 Emissions from HCFC-22 Production. Background Paper for
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References copied from the 2006 IPCC Guidelines

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SECTION 3.10.2 AND ANNEX 3A.1
References newly cited in the 2019 Refinement

Fthenakis, V., Clark, D.O., Moalem, M., Chandler, P., Ridegeway, R.G., Hulbert, F.E., Cooper, D.B. &Maroulis, P.J. (2010) Life-Cycle of Nitrogen Trifluoride Emissions from Photovoltaics. Environmental
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Chapter 3:Chemical Industry Emissions

U.S. Environmental Protection Agency (US EPA) (1995) 1995 Protocol for Equipment Leak Emission Estimates.
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SECTION 3.11
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Ogden J. M. (1999) Prospects for building a hydrogen energy infrastructure. Annual Review of Energy and theEnvironment 24(1): 227-279.
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