Based on the facility count assessment, there are three known LNG import facilities that have not reported GHG emissions to the GHGRP. According to the Department of Energy (DOE) Office of Oil and Gas LNG Monthly Reports, published in February 2021 and February 2022, none of the three LNG import facilities received LNG imports in 2020 or 2021. Therefore, their facility-level emissions are assumed to be zero for the near future.
Therefore, no facilities are expected to exceed the 25,000 mt CO2e threshold for the first time in the LNG Import and Export Equipment industry segment of subpart W as a result of the proposed AR5 GWP changes.
Industry Segment 8: Natural Gas Distribution
Natural gas distribution companies are required to report the miles of pipeline mains and the number of pipeline services by pipeline material annually to DOT PHMSA using Form F7100.1-1. There do not appear to be any thresholds for reporting to DOT PHMSA, so the data reported are considered a complete listing of every facility that operates distribution pipeline mains and services as they are defined by the DOT. For the purposes of our analysis, we removed data that were associated with any commodity other than natural gas (e.g., propane, landfill gas) as the GHGRP only requires reporting of equipment leak emissions from Natural Gas Distribution facilities. We also removed any reporting entities that only reported pipeline services with no pipeline mains as these were assumed to be transmission companies that have direct service lines to customers, but no distribution mains. After these adjustments, we consider the remaining 1,360 records -- each representing a facility as its defined in the GHGRP -- in the DOT PHMSA annual reports to be a nationally comprehensive repository of facilities and key activity data, which form the foundation of this coverage and threshold analysis for Natural Gas Distribution facilities.
We first focused on the distribution mains and services emission sources, which typically account for 90% or more of the emissions reported to the GHGRP. There are pipeline materials that are included in the DOT PHMSA report that are not included in the GHGRP (e.g., recondition cast iron, ductile iron, other). Miles and services reported to DOT PHMSA under these materials were excluded from this analysis, which consisted of 0.1% of the mains and 3.3% of the services reported to PHMSA.
The DOT PHMSA data only contains activity data for distribution mains and services, but the GHGRP includes other emission sources for natural gas distribution, including transfer-distribution stations, metering and regulating stations, and combustion. After removing the emissions from transfer-distribution stations, metering and regulating stations, and combustion, the total remaining emissions from GHGRP facilities were directly compared to the total emissions from PHMSA. Accounting for the proposed AR5 GWPs in both estimates, the resulting pipeline emissions reported to PHMSA are nearly identical to the emissions reported to the GHGRP; meaning that 100% of the expected emissions are already reported to the GHGRP for Natural Gas Distribution facilities.
In RY2020, there were 164 Natural Gas Distribution facilities that reported to the GHGRP. This count is based on facilities that reported to GHGRP in RY2020 and includes facilities with emissions less than the 25,000 mt CO2e threshold. As noted previously, if a facility is reporting to the GHGRP currently, we have assumed they will continue to do so regardless of the proposed AR5 GWP changes.
Based on complete emissions coverage between PHMSA and GHGRP, there are no facilities expected to exceed the 25,000 mt CO2e threshold for the first time in the Natural Gas Distribution industry segment of subpart W as a result of the proposed AR5 GWP changes.
Industry Segment 9: Onshore Petroleum and Natural Gas Gathering and Boosting
Gathering and Boosting facilities and their component-level emissions are not well-characterized in any external (non-GHGRP) public dataset. As part of the 2020 updates to the GHGI, the EPA reviewed available sources for determining gathering and boosting activity and emissions data. The EPA detailed the results of their review in several memorandums, including "Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2018: Updates to Natural Gas Gathering & Boosting Station Emissions" and "Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2017: Updates to Natural Gas Gathering & Boosting Pipeline Emissions." The EPA concluded that, as subpart W reporting reflects data only from facilities that meet the reporting threshold, reported data must be scaled up to represent national total activity. For the purposes of this analysis, the GHGRP data is "scaled up" to estimate the non-GHGRP facility-level emissions.
In reviewing the data, we found that 122 facilities that have reported (or are currently reporting) to the GHGRP reported emissions are under the 25,000 mt CO2e threshold. For the purpose of our analysis, using the 122 facilities' emissions and throughputs with the portion of national production throughput not covered by the Gathering and Boosting industry segment in RY2020, we estimate there are approximately 34 non-GHGRP reporters. Of these, none are expected to exceed the direct emitter threshold after implementation of the proposed AR5 GWP changes. Therefore, there are no facilities expected to exceed the 25,000 mt CO2e threshold for the first time in the Onshore Petroleum and Natural Gas Gathering and Boosting industry segment of subpart W as a result of the proposed AR5 GWP changes.
Industry Segment 10: Onshore Natural Gas Transmission Pipeline
The key data used to assess the national count of facilities and associated emissions were taken from PHMSA Form 7100.2-1. This form contains a list of transmission pipeline owners and operators by operator ID and includes identifying information (e.g., company name, address) as well as transmission pipeline mileage by pipeline material type. Some modification of the PHMSA data was required such that they were consistent with the definition of facility, the definition of transmission pipeline, and the definition of owner or operator for the GHGRP industry segment.
The modifications to the PHMSA Form 7100.2-1 dataset included:
 Removing pipelines transporting any commodity other than natural gas;
 Removing any operator IDs that did not have onshore transmission pipeline mileage;
 Consolidating operator IDs, which involved aggregating the associated transmission pipeline mileage where the reported headquarters' address and company name were the same or similar to align records at the parent company level; and
 Mapping the existing GHGRP reporters to their PHMSA reported data.
The modifications yielded 667 unique parent companies (including the GHGRP facilities). We considered this to be the count of nationwide of transmission pipelines potentially subject to the GHGRP.
National- and facility-level emissions from transmission pipelines are estimated from equipment leaks and blowdowns along the pipeline. To estimate blowdown emissions, we used RY2020 reported GHGRP data for all onshore transmission pipeline facilities that reported to the GHGRP. To estimate blowdown emissions from non-reporting onshore transmission pipeline facilities, we used the RY2016 - RY2020 GHGRP reported blowdown emissions to develop nationwide CH4 and CO2 blowdown emission factors. These emission factors were estimated by dividing the GHGRP total reported emissions from blowdowns at Onshore Natural Gas Transmission Pipeline facilities by the GHGRP total reported miles of transmission pipelines. This method yielded an emission factor value of 0.71 mt CH4 per pipeline mile and 0.02 mt CO2 per pipeline mile. These emission factors were then used with the pipeline mileage activity data reported to PHMSA to estimate nationwide blowdown emissions from non-GHGRP reporting facilities.
Therefore, only one facility is expected to exceed the 25,000 mt CO2e threshold for the first time in the Onshore Natural Gas Transmission Pipeline industry segment of subpart W as a result of the proposed AR5 GWP changes.
Total New Reporters for Subpart W
Table 4.9-4 shows the number of new reporters by industry segment for subpart W. As a result of the proposed AR5 GWPs, an additional 188 facilities are expected to report to subpart W.
Table 4.9-4. Total Number of New Reporters for Each Subpart W Industry Segment
Industry Segment
Number of New Reporters Resulting from GWP Changes
Offshore Petroleum and Natural Gas Production
7
Onshore Petroleum and Natural Gas Production
40
Onshore Natural Gas Processing
0
Onshore Natural Gas Transmission Compression
130
Underground Natural Gas Storage
9
LNG Storage
1
LNG Import and Export Equipment
0
Natural Gas Distribution
0
Onshore Petroleum and Natural Gas Gathering and Boosting
0
Onshore Natural Gas Transmission Pipeline
1
TOTAL
188

 4.10 Subpart DD
40 CFR part 98 subpart DD (subpart DD) currently requires reporting of GHG emissions from the electricity transmission and distribution sector. This source category currently consists of all electric transmission and distribution equipment and servicing inventory insulated with or containing SF6 or PFCs that are used within an electric power system (40 CFR 98.300(a)). Electric transmission and distribution equipment includes gas-insulated substations, circuit breakers, transformers, closed-pressure switchgear, hermetically sealed-pressure switchgear, gas-insulated lines, and gas storage containers (e.g., pressurized cylinder, gas carts). Facilities are required to report emissions of SF6 and PFCs, as well as other data used to verify the emissions are reported correctly. The SF6 and PFC emissions are multiplied by their respective GWPs to calculate the facility's CO2e emissions. SF6 is the most commonly used greenhouse gas within this sector and to date is the only gas that has been reported to the GHGRP.
Under the current rule, any facility whose total nameplate capacity of SF6- and PFC-containing equipment (excluding hermetically sealed-pressure equipment) located at the facility or under common ownership or control that is greater than 17,280 pounds is subject to subpart DD (40 CFR 98.301(a)). Unlike other direct emitter subparts, subpart DD applicability is determined separately from all other subparts. Hence, being subject to another subpart (e.g., subpart D) does not make the facility subject to reporting under subpart DD and vice versa. Subpart DD facilities that also meet the applicability criteria for another subpart (e.g., subpart D) are directed to report their subpart DD data under a separate GHGRP ID.
EPA proposed several changes to this subpart to improve the quality of the data collected (87 FR 36920, June 21, 2022). These changes include (1) adding fluorinated greenhouse gases (F-GHGs) other than SF6 and PFCs to the monitoring, calculation, and reporting requirements; (2) revising the applicability criteria; (3) adding several new definitions; and (4) adding new procedures in 40 CFR 98.303(b) for measuring the nameplate capacity values for new and retiring equipment.
EPA's proposal to establish a procedure allowing reporters to measure and revise the nameplate capacities of their new and retiring electrical equipment, if adopted, would increase the accuracy of the nameplate capacity values used in calculating emissions of SF6 and other insulating GHGs from electrical equipment. It also responds to a long-standing request from the industry for clarification on this matter. The proposed new procedures apply only to facilities that elect to measure the nameplate capacities of new and retiring equipment rather than relying on the rated nameplate capacities provided by equipment manufacturers.
The proposed changes to applicability and the gases reported address the recent development by equipment manufacturers of new insulating gases that have much lower GWPs than SF6 or PFCs. These gases have begun to be used in some applications in other countries and the EPA is aware that some electric power systems are currently using or considering using these alternative gases in the United States. Although currently used in only small quantities, it is likely their use in the United States will increase. The new gases include fluoroketones and fluoronitriles, which are used as mixtures with carrier gases. These mixtures have much lower GWPs, ranging from less than 1 for fluoroketones to 300 - 500 for fluoronitriles. Table 4.10-1 lists the alternative gases currently available for use in this sector with their typical compositions and GWPs. It is likely that GHG emissions for this sector will decrease in the future due to the lower GWPs of these gases and because they are used only as dilute mixtures. However, we expect the new gases to be adopted slowly over the next decades due to the limited range of products currently marketed and the long lifetime of existing electrical equipment (typically over 40 years).
Table 4.10-1. Composition of Alternative Gases Currently Available for Use in Electric Transmission and Distribution Equipment
                                Characteristics
                               CF4-Fluoronitrile
                               CF5-Fluoroketone
Chemical Formula
(CF3)2CFCN
(CF3)2CFC(O)CF3
100 Year GWP of Gas
2,100
<1
Typical Composition of Mixture
3  -  5% (CF3)2CFCN
95  -  97% CO2 and O2
10% (CF3)2CFC(O)CF3
90% mixture of O2 and N2, or CO2
100 Year GWP of Mixture
<500
<1

With the potential for alternate gases to become widely used in the future, the EPA has proposed changes to the current applicability threshold. Currently, a facility becomes subject to subpart DD if the total nameplate capacity of SF6- and PFC-containing equipment (excluding hermetically sealed-pressure equipment) located within the facility, when added to the total nameplate capacity of SF6- and PFC-containing equipment (excluding hermetically sealed-pressure equipment) that is not located within the facility but is under common ownership or control, exceeds 17,820 pounds. This threshold was calculated by EPA during the development of subpart DD to establish a nameplate capacity that approximates a typical nameplate capacity that would be expected to emit 25,000 mt CO2e if filled with SF6. To determine applicability, facilities would calculate CO2e emissions using the proposed new Equation DD-1, which accounts for the GWP of gases used and is an estimate of potential emissions from the source that may differ from the actual emissions reported under this subpart. The actual emissions are calculated annually using a mass-balance equation provided in the rule. The actual emissions may be significantly lower than the applicability emissions when a facility has implemented emission reduction practices.
In addition to the proposed amendments described above, EPA proposed updating the GWPs in Table A-1 to subpart A. The GWP change expected to affect subpart DD emissions is shown in Table 4.10-2.
Table 4.10-2. Applicable GWP Change for Subpart DD
                                      GHG
                                  Current GWP
                                    AR5 GWP
                                    Change
SF6
22,800
23,500
Increase

This analysis determined the impact of the revised AR5 GWPs and proposed reporting of other F-GHGs on the number of new reporters. For this analysis, we recalculated the CO2e for existing reporters using the SF6 emissions they reported in RY2020 and the AR5 GWP of 23,500. The method used to evaluate reporter burden consists of three steps, as follows:
 Identify currently reporting facilities reporting less than 25,000 mt CO2e per year that are on track to off-ramp but who are expected to begin reporting above 25,000 mt CO2e per year again as a result of the AR5 GWP change.
 Identify previously off-ramped subpart DD facilities and determine whether they will potentially re-enter the GHGRP as a result of the AR5 GWP change.
 Identify facilities that are not currently subject to the GHGRP and assess their potential to begin reporting as a result of the AR5 GWP change.
4.10.1 Current Reporters
Subpart DD has a number of facilities in the process of off-ramping (i.e., below 25,000 mt CO2e for RY2020 but not yet meeting the required number of years below the threshold). We used the SF6 emissions from the last year they reported to recalculate the CO2e using the AR5 GWP. The recalculated CO2e values for these facilities were then compared to the 25,000 mt CO2e threshold to determine whether any of the existing reporters would likely become ineligible to off-ramp.
To determine the impact on these facilities, we first examined the CO2e for facilities that reported emissions between 24,300 and 25,000 mt CO2e using the current GWP of 22,800 in RY2020. Two facilities (1000326 and 1008343) reported RY2020 CO2e within this range. In Table 4.10-3, the CO2e for the past five years calculated using the existing GWP are compared with the values calculated using the AR5 GWPs. The CO2e for each facility would increase by approximately 3%.
Table 4.10-3. Recalculated CO2e from Potential Off-Ramping Facilities
                                  Facility ID
                                      GWP
                                    RY2016
                                    RY2017
                                    RY2018
                                    RY2019
                                    RY2020
1000326
22,800
62,372
43,219
57,191
34,925
24,345

23,500
64,287
44,546
58,947
35,997
25,092
1008343
22,800
34,109
12,390
1,053
3,625
24,632

23,500
35,156
12,770
1,085
3,736
25,389

Based on the current GWP, facility 1000326 may have become eligible to stop reporting in future years if emissions remained at the current level. However, this facility would likely be ineligible to cease reporting if the AR5 GWP for SF6 is adopted based on their RY2020. Facility 1008343 could have ceased reporting after RY2019 due to reporting three years of emissions less than 15,000 mt CO2e. However, if the AR5 GWP for SF6 is adopted and emissions for this facility remain at the level reported in RY2020, this facility would no longer qualify for the off-ramp and would be required to continue reporting.
Based on these conservative assumptions, we determined that an additional two facilities are expected to report to subpart DD as a result of the proposed revised AR5 GWPs.
We also considered the impact of the proposed reporting of the new insulating gases (i.e., fluoronitriles and fluoroketones) on these reporters. Since EPA does not currently collect data on these gases, we do not know how many facilities currently use these alternatives and are not able to quantify the potential change in CO2e emissions for each facility. Instead, we assessed how much emissions of these gases would be needed to have an impact. For current and previous reporters whose CO2e is below 25,000 mt, we calculated the theoretical amount of CF4-fluoronitrile required to bring the facility above the 25,000 mt CO2e threshold. We selected CF4-fluoronitrile for this analysis because it has the highest GWP of the currently available alternative gases. We then qualitatively assessed whether any facility would be likely to emit CF4-fluoronitrile in the quantity calculated using information on the current availability and use of equipment containing CF4-fluoronitrile as the insulating gas.
In this analysis, we considered the facility with emissions closest to 25,000 mt CO2e using the AR5 GWP without being over this threshold. The facility (GHGRP ID 1009894) with the highest recalculated CO2e had 23,856 mt CO2e (equivalent to 1.015 mt SF6). We then calculated the amount of gas that would be required to emit the 1,144 mt CO2e to reach the 25,000 mt CO2e threshold. Assuming the use of CF4-fluoronitrile, the facility would need to emit 0.545 mt of CF4-fluorontirile. Using an annual emission factor of 0.1 (the same as assumed in Equation DD-1) and assuming a 5% CF4-fluoronitrile gas mixture, 0.545 mt is equivalent to emitting 10.9 mt of CF4-fluoronitrile gas mixture; more than 10 times the SF6 emissions reported by this facility in RY2020. As we noted earlier, the new insulating gases became available only in the last few years and are currently used in only small quantities. We consider it unlikely that any facility in the United States currently has CF4-fluoronitrile emissions this high.
Based on these conservative assumptions and the resulting high amount of CF4-fluoronitrile gas that would be required to exceed the 25,000 mt CO2e threshold, we determined that no existing reporters are potentially impacted by the proposed reporting of the new insulating gases.
4.10.2 New Reporters
<IP_ADDRESS> Analyses of Previously Off-Ramped Facilities
Subpart DD has a number of previous reporters who off-ramped from reporting prior to RY2020. We used the SF6 emissions from the last year they reported to recalculate the CO2e using the AR5 GWP. The recalculated CO2e values for these facilities were then compared to the 25,000 mt CO2e threshold to determine whether any of the facilities that previously off-ramped would be required to recommence reporting again.
Using the last year of reported emissions for each facility that off-ramped, we recalculated CO2e using the AR5 GWP for SF6. No facility had recalculated emissions greater than 25,000 mt CO2e.
Next, we considered whether the reporting of the new gases (i.e., fluoronitriles and fluoroketones) would be likely to bring the total CO2e emissions above the 25,000 mt threshold that would require the off-ramped facility to recommence reporting. The highest CO2e emissions reported by any of these facilities in their final year reporting was 15,645 mt CO2e. Similar to the analysis in the previous section, we calculated this facility would need to emit 4.45 mt CF4-fluoronitirile (pure gas, not as-used) (equivalent to 89 mt of a 5% CF4-fluoronitirile gas mixture) in order to exceed the 25,000 mt CO2e threshold. Assuming a 10% emission rate, this amount corresponds to having approximately 44.5 mt CF4-fluoronitirile (pure gas, not as-used) contained in equipment (or 898 mt nameplate capacity of equipment for a 5% CF4-fluoronitirile gas mixture). As we noted earlier, the new insulating gases became available only in the last few years and are currently used in only small quantities. We consider it unlikely that any facility in the United States currently has CF4-fluoronitrile emissions this high.
Based on these conservative assumptions and the resulting high amount of CF4-fluoronitrile gas-containing equipment that would be required to exceed the threshold, we consider it unlikely that the proposed changes to the SF6 GWP and the proposed reporting of other F-GHGs would result in any facility that previously off-ramped being required to begin reporting again.
<IP_ADDRESS> Analyses of Non-Reporters Entering the GHGRP
To determine whether any new facilities would be required to report if the proposed changes are adopted, we used the proposed applicability Equation DD-1 to calculate the CO2e for a facility using only SF6 and having 17,280 pounds of nameplate capacity, excluding hermetically sealed-pressure equipment (i.e., the current applicability threshold). We then calculated the additional nameplate capacity of CF4-fluoronitrile equipment required for the facility to exceed the proposed 25,000 mt CO2e threshold. We then qualitatively assessed whether any facility would be likely to have nameplate capacity of CF4-fluoronitrile in the quantity calculated using information on the current availability and use of equipment using CF4-fluoronitrile.
Assuming the SF6 AR5 GWP of 23,500, for the weight fraction of SF6 in the insulating gas, and the proposed Equation DD-1, the applicability threshold is 23,453 lbs of nameplate capacity, if only SF6 is used. The current nameplate capacity threshold of 17,280 lbs is more conservative (i.e., more facilities are subject to this subpart) than using the proposed Equation DD-1 with a 25,000 mt CO2e threshold. A facility that has a total nameplate capacity (excluding hermetically sealed-pressure equipment) of less than 17,280 pounds and uses only SF6 would not become subject to reporting as a result of the proposed new applicability criteria and newly proposed GWP for SF6.
If a facility is using one of the new alternative gases, then it is theoretically possible for a facility to become subject to subpart DD because of the proposed new applicability criteria. However, the lower GWP and smaller mass fraction of the gas used make it unlikely a facility would become subject to reporting. For example, a facility that uses SF6 in equipment with a total nameplate capacity (excluding hermetically sealed-pressure equipment) of 17,280 lbs would estimate emissions for comparison to the applicability threshold of 18,419 mt CO2e based on the AR5 GWP of 23,500. This facility would need an additional 6,581 mt CO2e in estimated emissions to exceed the proposed 25,000 mt CO2e threshold. Emissions of 6,581 mt CO2e for a facility using a 5% mixture of CF4-fluoronitrile and assuming a 0.1 emission factor is equivalent to operating a total nameplate capacity of 1,381,771 lbs. As noted above, use of the new insulating gases is currently very limited and expected to grow slowly over the next several years. We consider it to be very unlikely that any facility will operate over 1.3 million pounds of total nameplate capacity (excluding hermetically sealed-pressure equipment) containing the new insulating gases (while simultaneously having less than 18,000 lbs of total SF6 nameplate capacity) within the next three years.
For this reason, we conclude that no new reporters are likely to become subject to this subpart due to the proposed new applicability criteria and proposed revised AR5 GWPs.
We do not expect the newly proposed procedures for measuring the capacity of new and retiring electrical equipment to have a significant impact on the number of facilities required to report. Some facilities may continue to use the nameplate capacity as allowed in the existing rule. For reporters that elect to use the proposed new procedures, the difference between the measured capacity and the manufacturer's nameplate capacity for each unit is expected to be small. The emissions may increase or decrease depending on whether the measured value for each individual unit is greater than or less than the nameplate capacity. The overall impact on reported emissions is expected to be minimal as only a few new units enter service and a few old units are retired during a typical calendar year.
 4.11 Subpart FF
40 CFR part 98 subpart FF (subpart FF) requires reporting of GHG emissions from active underground coal mines. Active underground mines are defined as those where mine development is underway, coal has been produced within the last 90 days, mine personnel are present in the mine workings, mine ventilation fans are operative, or when the mine is designated as an "intermittent" mine by the Mine Safety and Health Administration (MSHA). Subpart FF does not include emissions from abandoned underground mines or surface mines.
Subpart FF is a direct emitter subpart with a reporting threshold in cubic feet of methane rather than metric tons of CO2. An owner/operator of an underground coal mine must report to the GHGRP if the mine liberates at least 36.5 million cubic feet (mmcf) per year of CH4. This equates to approximately 701 mt of methane per year or 17,525 mt CO2e per year at a GWP of 25 for CH4. Liberated means methane released from coal and surrounding rock strata during the mining process. Note that the quantity of methane liberated may not equal the quantity of methane emissions because some subpart FF facilities recover and use methane, reducing the quantity of methane that is emitted to the atmosphere.
For subpart FF, the GWP changes shown in Table 4.11-1 are expected to affect reported emissions.
Table 4.11-1. Applicable GWP Changes for Subpart FF
                                      GHG
                                  Current GWP
                                    AR5 GWP
                                    Change
CH4
25
28
Increase
N2O
298
265
No Impact

4.11.1 New Reporters
Although the number of subpart FF facilities declined steadily between 2014 and 2019, five new facilities reported in RY2020 for a net increase of two facilities since RY2019. Conservatively, we assumed two new reporters each year in RY2021, RY2022, and RY2023. However, because the reporting threshold is based on cubic feet of methane versus metric tons of CO2, the change to AR5 GWP does not appear to be the driving factor for these six new reporting facilities.
As of RY2020, subpart FF facilities have only used the 3-year off-ramp provisions (40 CFR 98.2(i)(1) and 98.2(i)(2)). We reviewed all facilities that have claimed the 3-year off-ramp since reporting began in RY2011 to determine if any facility could become new reporters using the AR5 GWPs. Facilities that are no longer eligible for the off-ramp were added to the total number of reporting facilities for RY2023.
Only five facilities have claimed this off-ramp since 2011. We considered whether emissions reported to subparts C and D, in addition to subpart FF emissions, would impact facility emissions. None of the facilities reported either subpart. Therefore, the changes to AR5 GWPs will not impact any subpart FF facilities' eligibility for off-ramping.
We also reviewed the 39 subpart FF facilities that notified EPA of their intent to cease reporting since RY2011. We confirmed that all facilities remain closed through review of data on MSHA operating status.
Therefore, the change to AR5 GWPs would not result in new reporters. Thus, there is no change to the number of affected facilities in subpart FF for previously off-ramped facilities.
 4.12 Subpart HH
40 CFR part 98 subpart HH (subpart HH) requires reporting of CH4 emissions from municipal solid waste (MSW) landfills that accepted waste on or after January 1, 1980, and which generate CH4 equal to or greater than 25,000 mt CO2e annually. However, the facility is not required to report if all three of the following criteria are true:
 The MSW landfill did not receive waste on or after January 1, 2013;
 The MSW landfill had CH4 generation as determined using specified subpart HH calculations of less than 1,190 mt of CH4 in the 2013 reporting year; and
 The owner or operator of the MSW landfill was not required to submit an annual report under any requirement of part 98 in any reporting year prior to 2013.
Landfill gas consists primarily of CO2 and CH4 and is produced by anaerobic bacteria digesting organic waste in the landfill. As CH4 migrates through the landfill, some of it is converted to CO2 through oxidation. The amount of CH4 oxidized to CO2 may be subtracted from generation when determining applicability to subpart HH. Once a landfill is subject to reporting under subpart HH, the landfill reports annual CH4 emissions. For landfills that do not use a gas collection and control system (GCCS), CH4 emissions from the landfill equal CH4 generation adjusted (i.e., reduced) for oxidation. For landfills that do use a GCCS, CH4 emissions equal CH4 generation adjusted for oxidation, and adjusted for CH4 collected and destroyed on-site and/or sent off-site. Landfill facilities may stop reporting as a result of the off-ramp provisions in 40 CFR 98.2(i)(1) and 98.2(i)(2) provided they submit a notification to the EPA that announces the cessation of reporting and explains the reasons for the reduction in emissions. To stay out of the program, landfills must monitor their emissions annually to ensure they remain below 25,000 mt CO2e each year.
Landfills that are uncontrolled report GHGRP emissions using Equation HH-5, which is Equation HH-1 adjusted for oxidation. Equation HH-1 is a first order decay model that incorporates the amount of waste in a landfill, the degradable organic carbon (DOC) content of the waste, and a decay rate constant (k). Default values for DOC and k are listed in Table HH-1 and are selected based on three options for characterizing waste in HH-1 calculations: the bulk waste option, the modified bulk waste option, and the waste-specific option. EPA proposed changing some of the DOC and k values in Table HH-1 in June 2022. Table 4.12-1 shows these proposed changes.
Table 4.12-1. Proposed Changes and Additions to Select DOC and k Values in Table HH-1[a]
                                    Factor
                             Current Default Value
                            Proposed Default Value
                                     Units
DOC (bulk waste)
                                     0.20
                                     0.17
Weight fraction, wet basis.
DOC (bulk MSW, excluding inerts and C&D waste)
                                     0.31
                                     0.27

DOC (Uncharacterized MSW)
                                    ---[b]
                                     0.32

k values for Bulk Waste option and Modified Bulk MSW option
k (precipitation plus recirculated leachate <20 inches/year)
                                     0.02
                                     0.055
yr[−1]
k (precipitation plus recirculated leachate 20-40 inches/year)
                                     0.038
                                     0.111

k (precipitation plus recirculated leachate >40 inches/year)
                                     0.057
                                     0.142

k (uncharacterized MSW)
                                    ---[b]
                                0.055 to 0.142

[a] DOC = degradable organic carbon; k = methane decay rate constant
[b] Does not exist in the current version of Table HH-1

While uncontrolled landfills only report emissions using Equation HH-5, controlled landfills may report emissions with Equation HH-6 or Equation HH-8. For both equations, emissions equal generation minus the amount of CH4 that is recovered and destroyed and/or sent off-site. Equation HH-6 incorporates generation from Equation HH-1 while Equation HH-8 incorporates generation from Equation HH-7, which is based on the amount of CH4 recovered.
All GHGRP reported emissions must be converted to CO2e using the GWP for CH4. Table 4.12-2 shows the proposed AR5 GWP change for CH4.
Table 4.12-2. Applicable GWP Change for Subpart HH
GHG
Current GWP
AR5 GWP
                                      CH4
                                      25
                                      28
4.12.1 Current Reporters
In reviewing GHGRP data for RY2021 (extracted from Envirofacts on May 13, 2022), we identified 23 landfills that qualify for off-ramping in 2022, either because their 2021 emissions represent the fifth consecutive year of emissions being below 25,000 mt CO2e or they represent the third consecutive year of emissions being below 15,000 mt CO2e. For purposes of this analysis, we are assuming these 23 sites will stop reporting (i.e., off-ramp) in 2022.
We also identified 7 closed sites and 13 open sites for which 2021 emissions represented the second consecutive year of emissions being less than 15,000 mt CO2e and third-year emissions in 2022 are estimated to be less than 15,000 mt CO2e too. For purposes of this analysis, we are assuming these 20 sites will stop reporting in 2023.
4.12.2 New Reporters
<IP_ADDRESS> Analyses of Previously Off-Ramped Facilities
Based on a review of reported subpart HH data, as of RY2020, 179 landfills have stopped reporting to the GHGRP based on qualifying emissions and notification to EPA. A few other landfills with qualifying emissions have also stopped reporting but have not notified EPA; therefore, we are not evaluating these landfills in the burden analysis (due to lack of notification).
In summary, we identified 179 sites that have off-ramped. In 2023, these facilities will have to monitor their emissions using the new values for DOC, k, and GWP, where applicable to ensure their emissions are below 25,000 mt CO2e. While all sites will have to use the new GWP to evaluate emissions, only sites that monitor emissions with Equations HH-1 and HH-6 will have to use the new DOC and k values (sites that monitor emissions with Equations HH-7 and HH-8 do not use these values).
Landfills can off-ramp whether they are open or closed, as long as CH4 emissions meet the off-ramp provisions in 40 CFR 98.2(i)(1) and 98.2(i)(2). For uncontrolled landfills, CH4 generation adjusted for oxidation must be below these levels to off-ramp. Controlled landfills can meet these levels by reducing generation through use of a GCCS. When a landfill is open, its CH4 generation increases each year and reaches maximum generation the last year of waste acceptance. After a landfill is closed, CH4 generation decreases each year. For landfills that were closed their last year of reporting, their CH4 generation in 2023 will be less than what it was their last year of reporting. For landfills that were open their last year of reporting, generation will increase until they close. Due to the differences in CH4 generation between open and closed landfills, we assessed potential reporting burden differently for these two groups of landfills.
To evaluate reporting burden to off-ramped landfills that were closed their last year of reporting, we calculated their 2023 emissions using new and existing values for DOC, k, and GWP, where applicable and compared the changes. For uncontrolled sites we calculated their HH-1/HH-5 emissions and for controlled sites we estimated their last roll-up emissions (HH-6 or HH-8 emissions). Since we did not have information on CH4 recovery in 2023, we had to modify our calculations of HH-6 and HH-8 emissions, as described below.
For controlled landfills, CH4 emissions equal the amount of CH4 generated minus the amount of CH4 captured and controlled. For HH-8, both terms (CH4 generation and the amount of CH4 captured and controlled) are calculated based on recovered CH4. In lieu of not knowing recovery, we assumed a facility's HH-8 roll-up emissions equaled their existing emissions in 2023. To calculate "new" HH-8 emissions for 2023, we increased the existing emissions by 12%, which is the percent change associated with increasing the GWP for CH4 from 25 to 28.
For controlled landfills reporting with HH-6 emissions, in lieu of not knowing their recovery, we assumed their generation (which is calculated using HH-1) equaled their facility emissions in 2023. We calculated new and existing HH-1 generations in 2023 based on a site's annual waste acceptance rate, and new and existing values for DOC and k associated with the bulk waste option. We chose values associated with the bulk waste option as it is one of the most frequently selected options by GHGRP reporters. Referring to Table 4.12-1, the bulk waste option values we used were 0.20 for existing DOC; 0.17 for new DOC; 0.038 for existing k; and 0.111 for new k. We adjusted existing and new HH-1 generations for 10% oxidation and converted them to CO2e using the new and existing GWPs (28 and 25, respectively).
For uncontrolled sites, we calculated new and existing HH-5 emissions, which are HH-1 generation emissions adjusted for oxidation. We calculated new and existing HH-1 generations based on a site's annual waste acceptance rate, and new and existing values for DOC and k associated with the bulk waste option. We adjusted both generations for 10% oxidation and converted them to CO2e using the new and existing GWPs.
We also evaluated the reporting burden for off-ramped landfills that are currently open. Most open landfills that off-ramped used a GCCS to reduce emissions below 25,000 mt CO2e. Since generation increases from open landfills, over time their generation may become too great to maintain generation below 25,000 mt CO2e with their GCCS. Therefore, some open sites that off-ramped are expected to report again in the future. To assess burden, we estimated the maximum generation from open sites that have off-ramped using both new and existing values of DOC, k, and GWP. We evaluated whether both maximum generations might lead to reporting again or if only the new maximum generation would trigger reporting.
We identified 179 sites that have off-ramped. To evaluate reporting burden for closed landfills that have off-ramped, we calculated their 2023 emissions using new and existing values for DOC, k, and GWP and compared the changes. For controlled sites, we calculated their HH-6 or HH-8 emissions in 2023 (depending on which equation they last reported with), and for uncontrolled sites we calculated their HH-5 emissions in 2023.
For closed landfills that selected their HH-6 emissions as their final roll-up emissions before off-ramping we modeled existing and new HH-6 emissions in 2023 using a first order decay equation to determine if new values of DOC, k, and GWP would increase generation. Except for one landfill, the combination of these parameters led to negative percent changes in generation, indicating that the combined effect of the proposed new changes to DOC, k, and GWP accelerates the decline of HH-6 emissions from closed landfills. Due to their decreasing generation, we do not believe these closed landfills will report again. We also believe the one landfill that saw a positive change (14%) is an anomaly (likely due to the "screening nature" of our generation calculation) as this landfill last reported in 2018, and emissions were less than 15,000 CO2e.
For closed landfills that selected their HH-8 emissions as their final roll-up emissions before off-ramping, we used these final emissions as their 2023 HH-8 emissions. We then increased these "existing" emissions by 12% (GWP percent change proposed) to estimate "new" emissions in 2023. None of the "new" emissions reached 25,000 mt CO2e, indicating that existing emissions are low enough that increasing them by 12% in 2023 will not trigger reporting. Based on these results, we do not believe these landfills will report again due to their decreasing emissions.
For the closed, uncontrolled landfills that have off-ramped, we modeled existing and new HH-5 emissions in 2023 using a first order decay equation to determine the impact of the new values of DOC, k, and GWP on generation. Except for one landfill, the combination of these parameters led to negative percent changes in generation, indicating that the combined effect of the proposed new changes to DOC, k, and GWP accelerates the decline of generation emissions (HH-1/HH-5) from closed landfills. Due to their decreasing generation, we do not believe these closed landfills will report again. We also believe the one landfill that saw a positive change (14%) in generation is an anomaly (likely due to the "screening nature" of our generation calculation) as this landfill last reported in 2012, and emissions were less than 15,000 mt CO2e.
For the open landfills where we modeled maximum generations using new and existing values for DOC, k, and GWP, all but five had similar new and existing generations (within +-7% of one another). For landfills with similar new and existing generations, we are not counting the new changes to DOC, k, and GWP as a burden to these landfills as we believe their similar generations will trigger the same reporting requirement in the future. On the other hand, for the five landfills where the new maximum generation is somewhat higher than existing generation (11%, 23%, 30%, 30%, and 31% differences at the five landfills) the new maximum generation may cause reporting that the existing generation might not. Note, while open landfills that have off-ramped have increasing generation each year (since they're open), if they keep emissions below 25,000 mt CO2e by upgrading or expanding their GCCS they can remain out of the program. This might be the case for the five landfills we modeled with slightly higher new maximum generations. However, to be conservative, we determined that an additional five landfills are expected to report to subpart HH as a result of the proposed revised AR5 GWPs.
<IP_ADDRESS> Analyses of Non-Reporters Entering the GHGRP
For landfills that have never reported to the GHGRP, we estimated burden to this group based on how many nonreporters would have to report only because of proposed changes to DOC, k, and GWP. In other words, if existing values of DOC, k, and GWP eventually require a nonreporting facility to report, we did not count this as a burden to the facility. We used RY2024 to evaluate the effect of the new changes on nonreporters as the rule states that for nonreporters, reporting with new values starts the RY following their publication.
As noted earlier, landfills are subject to reporting if their generation equals or exceeds 25,000 mt CO2e. Assuming all nonreporting landfills are complying with the rule, (i.e., assuming none have reached 25,000 mt CO2e), nonreporting landfills are either (1) open landfills that have not reported because their generation has not reached 25,000 mt CO2e or (2) they are closed landfills that did not generate 25,000 CO2e or more while they were open.
To conduct a burden analysis, we identified nonreporting landfills using the EPA's Landfill Methane Outreach Program (LMOP) Landfill and Landfill Gas Energy Database (LMOP database). The LMOP database currently contains information on 2,634 MSW landfills, which represents the majority of MSW landfills in the United States. The database contains various information about the landfills such as physical address, latitude and longitude, owner/operator organization, operational status, year opened, actual or expected closure year, design capacity, amount of waste in place (WIP), gas collection system status, and GHGRP ID (if a landfill has ever reported to the GHGRP).
The LMOP database was last updated March 2022 and includes 1,307 landfills that have never reported to the GHGRP. Based on available closure information, 1,003 of these landfills received waste on or after January 1, 1980, which makes them potentially subject to subpart HH. Based on available information on design capacity and opening and closure years, we were able to model generation in RY2024 for 119 of these landfills. We modeled generation using new and existing values of DOC and k associated with the bulk waste option; adjusting the generations for 10% oxidation; and converting them to CO2e using the new and existing GWPs (28 and 25, respectively). We then assessed the magnitude of these generations and whether we thought they would trigger reporting in the future.
We were able to model generation from 119 landfills that have never reported to the GHGRP, presumably because their generation has never reached 25,000 mt CO2e. Of these modeled landfills, 85 were closed and 34 were open. To evaluate reporting burden for these landfills, we evaluated their maximum generation using new and existing DOC, k, and GWP values.
For the 85 closed nonreporting landfills we modeled, all but three had "new" generation emissions in 2024 that were less than their existing generation emissions in 2024. As noted above, these findings indicate that the combined effect of the June 2022 proposed changes to DOC, k, and GWP accelerates the decline in generation from closed landfills. Since these landfills are closed and have never reported, this means their generation never reached 25,000 mt CO2e while they were open. Now that they're closed, their existing generation in 2024 is even further below 25,000 mt CO2e. The proposed changes indicate that their "new" emissions will be even further below existing levels, therefore we do not believe these 85 closed landfills will report again. In fact, based on these results, we do not believe any landfill that is closed and has not reported to the GHGRP will be required to report in the future.
Regarding the three closed landfills that had positive changes in their generation (2%, 3%, and 16% positive differences), we believe the results are an anomaly, and a product of the "screening" nature of our calculations. We believe these landfills have emissions below 25,000 mt CO2e since these landfills are closed and have never reported, meaning when they were open, their generation never reached 25,000 mt CO2e to trigger reporting. Furthermore, by 2024 all three landfills will have been closed for 19, 24, and 41 years. Therefore, we do not believe these three closed landfills will have to report in the future.
For the 34 open nonreporting landfills we evaluated based on new and existing maximum generations (using new and existing values for DOC, k, and GWP), our results indicate that 24 landfills will eventually exceed 25,000 mt CO2e in generation using either new or existing values for DOC, k, and GWP, thus, we are not counting the new values as a reporting burden to these landfills. For nine landfills, existing and new maximum generations are not expected to reach 25,000 mt CO2e, while for one landfill, its new maximum generation exceeded 25,000 mt CO2e while its existing maximum generation did not. Thus, this one additional landfill is expected to report to subpart HH as a result of the proposed revised AR5 GWPs.
 4.13 Subpart II
40 CFR part 98 subpart II (subpart II) requires reporting of GHG emissions from industrial wastewater and treatment sludge sources at pulp and paper manufacturing, food processing, ethanol production, and petroleum refining facilities. Facilities reporting to subpart II are typically required to report to the GHGRP because emissions from primary industrial activities at the facility are regulated under other subparts (e.g., subpart Y [Petroleum Refineries] and subpart AA [Pulp and Paper Manufacturing]). Facilities must also report to subpart C (Stationary Combustion) if the wastewater treatment system is associated with a biogas destruction device or if there are other stationary combustion sources on site at the facility.
Subpart II facilities are required to report the amount of CH4 generated, emitted, and/or recovered from the following sources: anaerobic lagoons or reactors, anaerobic sludge digesters, and biogas collection and destruction devices. Since industrial wastewater treatment facilities are expected to produce little to no CO2 or N2O if functioning properly, only the CH4 content of the biogas is included in the net GHG emissions under the GHGRP. As shown in Table 4.13-1, the GWP for CH4 being increased from 25 to 28 will increase calculated CO2e emissions and has the potential to increase the number of facilities reporting to the GHGRP.
Table 4.13-1. Applicable GWP Changes for Subpart II
                                      GHG
                                  Current GWP
                                    AR5 GWP
                                    Change
                                      CH4
                                      25
                                      28
                                   Increase

Facilities that are subject to reporting under subpart II may stop reporting as a result of the off-ramp provisions in 40 CFR 98.2(i)(1) and 98.2(i)(2). The burden evaluation is presented for off-ramped facilities as of RY2020, projected off-ramp facilities that may be brought back into the program in RY2023 with the new CH4 GWP, and facilities that may be required to start reporting to the GHGRP for the first time after the GWP revisions are adopted. We assumed the GWP revisions will be incorporated for RY2023 for active and off-ramped reporters and for RY2024 for new reporters.
All petroleum refineries subject to subpart Y are required to report to the GHGRP. Similarly, all pulp and paper manufacturing facilities with anaerobic treatment sources are expected to meet the reporting requirements of emitting 25,000 mt CO2e or more annually. Emissions from petroleum refineries and pulp and paper manufacturing facilities will exceed their reporting thresholds based on their subpart C, subpart Y, and/or subpart AA CO2e emissions alone. Increased subpart II emissions from the new AR5 CH4 GWP will not affect the reporting status of these facilities because subpart II emissions typically have minor contributions to the overall facility emissions at these industrial sites. Furthermore, the AR5 CH4 GWP increase for subpart C (and any subparts using subpart C combustion factors) was determined to be offset by the AR5 N2O GWP decrease, resulting in negligible changes in subpart C emissions (as discussed in Section 2.2). The burden evaluation methodology for subpart II focused on subpart II facilities that do not also report to subpart Y and AA.
4.13.1 Current Reporters
Each subpart II facility with emissions less than 25,000 mt CO2e were further evaluated to determine whether they are projected to off-ramp.
For this analysis, projected off-ramp facilities are defined as those that are assumed to cease reporting prior to RY2023. To determine this group of facilities, RY2021 and RY2022 emissions were estimated using past reported data for all applicable subpart II facilities. Additionally, the variability of prior year data was reviewed to determine if emissions were consistent or inconsistent. For cases where prior year (RY2016 to RY2020) emissions were consistently below off-ramp provisions in 40 CFR 98.2(i)(1) and 98.2(i)(2) and the facility is eligible to cease reporting for the first time in either RY2021 or RY2022, it was assumed that these facilities will cease reporting prior to RY2023. This subset of facilities was then evaluated to determine if the subpart II CH4 increase in RY2023 would raise emissions over the 25,000 mt CO2e threshold. If this is true, then the facility was assumed to incur burden because they would be brought back into the program.
There are four facilities that reported emissions below 25,000 mt CO2e in 2020. We expect that three of those facilities will off-ramp prior to RY2023 because their emissions were consistent over the past five years and below 25,000 mt CO2e. Net emissions from these three facilities will stay below the 25,000 mt CO2e threshold after applying the AR5 CH4 GWP. The fourth facility does not meet the off-ramp requirements prior to RY2023 due to emissions exceeding 25,000 mt CO2e within the past five reporting years. Thus, there is no change to the number of affected facilities due to the proposed revised AR5 GWPs from projected off-ramp subpart II reporting facilities.
4.13.2 New Reporters
<IP_ADDRESS> Analyses of Previously Off-Ramped Facilities
For subpart II, we evaluated impacts on facilities that have already ceased reporting due to the off-ramp provisions between RY2014 to RY2020. These subpart II facilities were filtered to exclude facilities that also report subpart Y and subpart AA annual emissions, as they are expected to exceed the reporting thresholds for those subparts alone and will still report regardless of the AR5 CH4 GWP revision. The CO2e emission values for the remaining subpart II facilities were ranked from high to low, and then the facilities were evaluated after calculating the new total CO2e annual emission values using the updated AR5 CH4 GWP value. Each subpart II facility with existing CO2e emissions greater than the 25,000 mt CO2e threshold value are expected to continue reporting under subpart II after the AR5 CH4 GWP revision is implemented unless they are expected to have significant emissions reductions from other reported subparts.
There are 113 facilities reporting RY2020 subpart II emissions (excluding facilities that also report to subpart Y and subpart AA). Of these, 109 reported facility emissions above 25,000 mt CO2e, and the remaining 4 reported facility emissions below 25,000 mt CO2e (and were evaluated in the previous section). Since the AR5 CH4 GWP revision will result in emissions increases under subpart II, the 109 facilities reporting above 25,000 mt CO2e will be unaffected by these changes.
The subset of subpart II facilities that have already ceased reporting due to the off-ramp provisions between RY2014 to RY2020 were also evaluated. The AR5 CH4 GWP revision was applied to this subpart II dataset (using last reported facility emissions) to determine their assumed change in emissions. A burden increase was assumed if a facility's emissions went above the 25,000 mt CO2e threshold.
It was determined there will be no burden increase from previously off-ramped subpart II reporters, as their emissions will stay under the 25,000 mt CO2e threshold after the updated AR5 CH4 GWP value is applied. Table 4.13-2 highlights the previously off-ramped facilities' last reported CO2e emissions using the current and revised GWP values.
Table 4.13-2. Impact on Subpart II Off-Ramp RY CO2e Emissions
                                  Facility ID
                                  Off-Ramp RY
               Subpart II CO2e Emissions Reported in Off-Ramp RY
                Facility CO2e Emissions Reported in Off-Ramp RY
                 Revised Facility CO2e Emissions Under AR5 GWP
1009599
                                     2016
                                    11,791
                                    15,386
                                    16,801
1001671
                                     2020
                                      873
                                    22,828
                                    22,932

<IP_ADDRESS> Analyses of Non-Reporters Entering the GHGRP
New facilities that may be subject to reporting due to the AR5 CH4 GWP increase were assessed separately for subpart II sources at pulp and paper manufacturing, food processing, ethanol production, and petroleum refining facilities.
Petroleum refineries were excluded from the new subpart II reporter analysis because they are required to report to subpart Y and will therefore continue reporting to subpart II. Pulp and paper manufacturing facilities were also excluded from the new reporter analysis because all pulp and paper manufacturing facilities with anaerobic treatment sources are expected to exceed the reporting requirements of 25,000 mt CO2e annually under subpart AA and will therefore continue reporting to subpart II.
Since it is expected that only ethanol production facilities and food processing facilities may be brought into the GHGRP and there is little data that exist to estimate the population of these types of facilities, reporter burden was determined by reviewing the number of new reporters that entered the program in RY2014 following the promulgation of a new CH4 GWP in RY2013 (GWP was revised from 21 to 25). In RY2014, there was a 19% increase in the GWP (GWP revised from 21 to 25) and there were also six new subpart II reporters. These six facilities were further evaluated to determine which ones likely entered the program due to the 2013 GWP revisions. This analysis assumes that a relative increase will occur in RY2024 following a 12% increase (GWP revised from 25 to 28) in the CH4 GWP factor.
The overall new reporter impact for RY2024 was analyzed using the previous CH4 GWP revision from 21 to 25 in RY2014 to determine the impact on reporters under the new CH4 GWP revision from 25 to 28 in RY2024. The number of facilities reporting to subpart II from 2013 to 2014 increased by six following the previous GWP revision (19% increase). These facilities along with their reported subpart II and facility CO2e emissions are presented in Table 4.13-3.
Table 4.13-3. Subpart II RY2014 New Reporting Facilities with CO2e Emissions
                                   GHGRP ID
              Type of Facility (from Reported Primary NAICS Code)
                   RY2014 Reported Subpart II CO2e Emissions
                    RY2014 Reported Facility CO2e Emissions
1004276
                       Chemical Manufacturing (Ethanol)
                                      97
                                    181,382
1007824
                                Food Processing
                                     7,275
                                    61,578
1011710
                                Food Processing
                                    20,100
                                    37,384
1011551
                                Food Processing
                                     4,798
                                    27,043
1011725
                                Food Processing
                                     4,121
                                    25,362
1011785
                                Food Processing
                                     3,762
                                     3,762

It is likely that facilities 1011710, 1011551, and 1011725 started reporting subpart II emissions to the GHGRP in RY2014 due to the previous GWP increase. It appears that facilities 1004276 and 1007824 started reporting in RY2014 because they added anaerobic processes at the facilities for RY2014. Facility 1011785 was not subject to reporting based on their reported RY2014 emissions and therefore began GHGRP reporting for reasons other than exceeding the 25,000 mt CO2e threshold.
A 12% increase in CH4 emissions following the AR5 CH4 GWP revision is expected to result in two additional facilities in subpart II in RY2024. This was determined by the ratio of the number of new reporters in RY2014 divided by the 19% increase in the GWP in RY2014 (changing from 21 to 25) to the number of new reporters in RY2024 divided by the 12% increase in the GWP in RY2024 (changing from 25 to 28).
 4.14 Subpart OO
40 CFR part 98 subpart OO (subpart OO) is a supplier subpart that requires reporting of industrial GHG that are produced, imported, exported, or destroyed. These GHGs consist of N2O, F-GHGs, and HTFs. Many of the GHGs reported under this subpart have very high GWPs that result in high levels of CO2e from potentially small quantities of gases produced, imported, exported, or destroyed.
Facilities are subject to this subpart if they produce any amount of industrial GHGs, or import, export, or destroy the equivalent to 25,000 mt CO2e or greater. The thresholds for importing, exporting, and destroying are separate for each activity but cumulative for all gases within an activity. If a facility meets any of the activity thresholds to become subject to subpart OO, they must report all activities under the subpart.
Facilities may off-ramp from the GHGRP under the supplier provisions in 40 CFR 98.2(i)(4). A facility may cease reporting for one activity (e.g., importing) but still be required to report for a different activity (e.g., production).
Many GHGs are subject to reporting under this subpart. In addition, some GHGs may be reported to the GHGRP as "other" with a standard grouping and GWP selected by the reporter to best calculate CO2e based on the gas's chemical makeup. As such, a comprehensive list of all gases and expected GWP changes is not provided.
In addition to the AR5 GWP changes, EPA has proposed several revisions to the subpart OO rule. These include requiring reporters to provide additional documentation supporting import values and listing end users of the F-GHGs, if available. These changes will not impact the number of facilities that are required to report under this subpart.
4.14.1 Current Reporters
The first step of this analysis was to recalculate (using the revised GWPs) RY2020 quantities for GHGRP facilities that are expected to be affected by the AR5 GWP changes. These affected facilities are those with a total CO2e supplied less than (on a per-activity basis) 50,000 mt CO2e. The threshold of 50,000 mt CO2e supplied was chosen because it was believed that none of the revised GWPs will result in greater than 25,000 mt CO2e reduction in reported quantities. During the recalculation of RY2020 quantities, the analysis did confirm that no facility had an activity with reported CO2e greater than 50,000 mt CO2e and a recalculated value below 25,000 mt CO2e. The average percent change in reported CO2e supplied for GHGRP facilities was also calculated.
If step 1 concluded that subpart OO quantities from some or all facilities decreased, we then determined if these decreases will result in any facilities being eligible to off-ramp. Note that facilities may be eligible to cease reporting for one activity while still being required to report for others.
If step 1 concluded that subpart OO quantities from some or all facilities will increase, we then determined if any facilities that are in the process of off-ramping (i.e., have been reporting quantities below 25,000 mt CO2e for several years but are not yet eligible for off-ramping) may be prevented from doing so due to the GWP changes expected in RY2023. Reported quantities for RY2020 were recalculated and compared against the off-ramping thresholds. The number of facilities who would be prevented from off-ramping in the future due to the revised GWPs was determined.
The analysis found that for all activities the majority of facilities had decreased reported quantities when recalculated using the AR5 GWPs. Existing facilities may stop reporting as a result of the off-ramp provisions in 40 CFR 98.2(i)(1) and 98.2(i)(2). This is calculated on a per-activity basis. Reported quantities were recalculated for RY2020 to determine if any facility would be able to count quantities at the current reported level towards the time required under the off-ramping threshold when recalculated using AR5 GWPs. The analysis found that there were no facilities whose recalculated quantities dropped them beneath the off-ramping threshold and therefore there is no change in reporting burden for current subpart OO reporters due to decreased calculated quantities using the AR5 GWPs.
The analysis found that a number of facilities had increased quantities when recalculated using the AR5 GWPs. This portion of facilities accounted for a smaller number of facilities than those whose quantities decreased, but did include facilities from all activities. The analysis recalculated RY2020 values to determine if any facilities currently reporting below 15,000 mt or 25,000 mt CO2e would exceed one of those thresholds when recalculated. Increased quantities based on the AR5 GWPs could not result in existing reporters being prevented from off-ramping.
For one facility the data rose above the off-ramping threshold based on the AR5 GWPs. This facility only reported one activity under subpart OO, and did not report under any other subpart. Therefore, one subpart OO facility will continue to report to the GHGRP as a result of the proposed revised AR5 GWPs instead of exiting the GHGRP. No other facility had recalculated quantities for any activity exceed an off-ramping threshold under the AR5 GWPs.
4.14.2 New Reporters
If step 1 of the analysis (described in Section 4.14.1) concluded that subpart OO quantities from some or all facilities will increase, we then looked at two potential results of these changes. We then determined:
 If any previously off-ramped facilities from the program will be pulled back into the program. If a facility's revised quantities are greater than 25,000 mt CO2e under the new GWPs, they are assumed to be required to begin reporting again. This was evaluated by applying the new GWPs to their most recent reported quantities to see if they will exceed the reporting threshold. This was determined using existing data reported to the program and was calculated on a per-activity basis.
 If the revised GWPs result in increased total quantities for subpart OO reporters, this may require facilities to begin reporting to the GHGRP for the first time. This would not include facilities that produce industrial GHGs as there is no threshold below which reporting is not required. For importing, exporting, and destroying, facilities with quantities less than 25,000 mt CO2e that are not also producers are not required to report. The average increase in reported GHG supplied was used to determine how many facilities would become subject to subpart OO for the first time due to the GWP revisions and thus estimating the reporting burden.
<IP_ADDRESS> Analyses of Previously Off-Ramped Facilities
Facilities that have previously off-ramped from the program are required to begin reporting again if their quantities exceed 25,000 mt CO2e for any activity. There have been three facilities that have previously off-ramped. This analysis recalculated the last year of reported emissions from each facility, and none of the recalculated quantities exceeded 25,000 mt CO2e for any activity. None of these facilities would be required to begin reporting again under the revised AR5 GWPs.
<IP_ADDRESS> Analyses of Non-Reporters Entering the GHGRP
As a number of facilities had increased quantities of GHGs reported when recalculated using the AR5 GWPs, there are potentially new reporters that will enter the program. We used reported quantities for imports, exports, and destruction to determine the magnitude and direction of change in CO2e for a representative facility based on the weighted average GWP change for all chemicals. For each chemical, the percent of all reported GHG quantities of that chemical was multiplied by the percent change in GWP to reach the weighted average change. Once this was calculated for all chemicals, the weighted percent changes were summed to calculate an overall percent change for each activity.
This average change for each activity was then used to determine if any new facilities would be required to report. If the representative facility had a decrease in GHG quantity based on the AR5 GWP changes, no new facilities would likely be required to report. If the representative facility has an increase in quantity reported using the AR5 GWPs, then the percent increase will be used to estimate the number of new facilities subject to reporting.
The representative facility had a decrease in calculated CO2e using the AR5 GWPs for each activity, so it is more likely that a facility below the reporting threshold would have recalculated quantities decrease rather than increase. Therefore, there is no change to the number of affected facilities due to the proposed revised AR5 GWPs for subpart OO new reporters.
 4.15 Subpart QQ
40 CFR part 98 subpart QQ (subpart QQ) is a supplier subpart that requires reporting of industrial GHG, including SF6 and HFCs, that are contained in imported or exported pre-charged equipment or closed-cell foams. Electrical equipment, such as high-voltage circuit breakers, is commonly charged with SF6 for dielectric insulating and arc-quenching purposes. F-GHGs are often used as foam-blowing agents and in air conditioning systems. Many of the GHGs reported under this subpart have very high GWPs, which result in high levels of CO2e from otherwise small quantities of gases imported or exported.
Facilities are subject to this subpart if they import or export the equivalent to 25,000 mt CO2e contained within equipment or foams. The thresholds for importing and exporting are separate for each activity but cumulative for all gases within an activity. If a facility meets an activity threshold to become subject to subpart QQ, they must report both activities under the subpart.
As previously discussed, facilities may cease reporting to the GHGRP under the supplier provisions in 40 CFR 98.2(i). A facility may off-ramp for one activity (e.g., importing) but still be required to report for a different activity (e.g., exporting). Facilities and suppliers are required to notify EPA if they intend to cease reporting per any of the 40 CFR 98.2(i) provisions.
4.15.1 Current Reporters
The first step of this analysis was to recalculate (using the revised GWPs) RY2020 quantities for GHGRP facilities that are expected to be affected by the AR5 GWP changes. These affected facilities are those with a total CO2e supplied less than (on a per-activity basis) 50,000 mt CO2e. The threshold of 50,000 mt CO2e supplied was chosen because it is believed that none of the revised GWP will result in greater than 25,000 mt CO2e reduction in reported quantities. During the recalculation of RY20 quantities, the analysis confirmed that no facility had an activity with reported CO2e greater than 50,000 mt CO2e and a recalculated value below 25,000 mt CO2e. The average percent change in reported CO2e supplied for GHGRP facilities was also calculated.
If step 1 concluded that subpart QQ quantities from some or all facilities will decrease, we then determined if these decreases result in any facilities being eligible to off-ramp (i.e., if quantities drop below 25,000 mt CO2e). Note that facilities may be eligible to cease reporting for one activity while still being required to report for the other.
If step 1 of the analysis concluded that subpart QQ quantities from some or all facilities will increase, we then determined if any facilities that are in the process of off-ramping (i.e., have been reporting quantities below 25,000 mt CO2e for several years but are not yet eligible for off-ramping) may be prevented from doing so due to the GWP changes expected in RY2023. Reported quantities for RY2020 were recalculated and compared against the off-ramping thresholds. The number of facilities that would be prevented from off-ramping in the future due to the revised GWPs was determined.
The analysis found that for both activities the majority of facilities had decreased CO2e quantities when recalculated using the AR5 GWPs. Existing facilities are eligible to off-ramp from reporting if their reported quantities are less than 25,000 mt CO2e for five consecutive years or less than 15,000 mt CO2e for three consecutive years. This is calculated on a per-activity basis. Reported quantities were recalculated for RY2020 to determine if any facility would be able to count quantities at the current reported level towards the time required under the off-ramping threshold when recalculated using AR5 GWPs. The analysis found that there were three facilities for which recalculated quantities dropped them beneath the off-ramping threshold for a reported activity.
The analysis found that a number of facilities had increased quantities when recalculated using the AR5 GWP. This portion of facilities accounted for a smaller number of facilities than those that had quantities decreased. The analysis recalculated RY2020 values to determine if any facilities currently reporting below 15,000 mt or 25,000 mt CO2e would exceed one of those thresholds when recalculated. Increased quantities based on the AR5 GWPs could result in existing reporters being prevented from off-ramping. No facilities had an increase in either import or export quantities above either the 15,000 mt or 25,000 CO2e threshold. Therefore, there is no change to the number of affected facilities due to the proposed revised AR5 GWPs for subpart QQ current reporters.
4.15.2 New Reporters
If step 1 of the analysis (described in Section 4.15.1) concluded that subpart QQ quantities from some or all facilities will increase, we then looked at two potential results of these changes. We then determined:
 If any previously off-ramped facilities from the program will be pulled back into the program. If a facility's revised quantities are greater than 25,000 mt CO2e under the new GWPs, they are assumed to be required to begin reporting again. This was evaluated by applying the new GWPs to their most recent GHGRP quantities to see if they will exceed the reporting threshold. This was determined using existing data reported to the program and was calculated on a per-activity basis.
 If the revised GWPs result in increased total quantities for subpart QQ reporters, this may require facilities to begin reporting to the GHGRP for the first time. Facilities with quantities less than 25,000 mt CO2e are not required to report. The average increase in reported GHG supplied was used to determine how many facilities would become subject to subpart QQ for the first time due to the GWP revisions.
Facilities that have previously off-ramped from the program are required to begin reporting again if their quantities exceed 25,000 mt CO2e. There has been one facility that has previously off-ramped. This analysis recalculated the last year of reported emissions and determined that the facility would not be required to restart reporting.
As a number of facilities had increased quantities of GHGs reported when recalculated using the AR5 GWPs, there are potentially new reporters that could be required to enter the program. We used reported quantities for imports and exports to determine the magnitude and direction of change in CO2e for a representative facility based on the weighted average GWP change for all chemicals. For each chemical, the percent of all reported CO 2e for that chemical was multiplied by the percent change in GWP to reach the weighted average change for that chemical. Once this was calculated for all chemicals, the weighted percent changes were summed to calculate an overall percent change for each activity.
This average change for each activity was then used to determine if any new facilities would be required to report. If the representative facility had a decrease in GHG quantity based on the AR5 GWP changes, no new facilities would likely be required to report. If the representative facility had an increase in quantity reported using the AR5 GWPs, then the percent increase would be used to estimate the number of new facilities subject to reporting.
The representative facility had a decrease in calculated CO2e using the AR5 GWPs for both activities, so it is more likely that a facility below the reporting threshold would have recalculated quantities decrease rather than increase. Therefore, this analysis determined that the AR5 GWP revisions will not result in a change to the number of affected facilities for subpart QQ new reporters.
 4.16 Subpart SS
40 CFR part 98, subpart SS (subpart SS) currently requires reporting of GHG emissions from facilities that manufacture, install, and/or refurbish electrical equipment that contain SF6 and PFCs (40 CFR 98.450). Under the current rule, any facility in this source category that has combined annual purchases of SF6 and PFCs greater than 23,000 lbs in a calendar year must begin reporting emissions from equipment testing, installation, manufacturing of new equipment, decommissioning and refurbishing of old equipment, and gas storage. This includes emissions from equipment that is installed at an off-site electric power transmission or distribution location if the emissions occur before the title to the equipment is transferred to the electric power transmission or distribution entity. Five facilities are currently subject to subpart SS. Two other facilities were subject to reporting in prior years but have since exited the GHGRP. All subpart SS facilities reported emissions of SF6 and only one facility has reported emissions of a PFC (perfluoromethane (PFC-14)) to date. The emissions of SF6 make up over 99% of all emissions reported to the GHGRP for this source category.
In addition to reporting SF6 and PFC emissions, some subpart SS facilities have fossil fuel-fired combustion units. The combustion emissions are generally low but must be reported in accordance with the provisions of subpart C. Three of the five subpart SS facilities that reported in RY2020 also reported combustion emissions under subpart C (40 CFR 98.451).
EPA has proposed updating the GWPs in Table A-1 to subpart A. The GWP changes expected to affect subpart SS emissions are shown in Table 4.16-1.
            Table 4.16-1. Applicable GWP Changes for Subpart SS[a]
                                      GHG
                                  Current GWP
                                    AR5 GWP
                                    Change
SF6
22,800
23,500
Increase
PFC-14 (perfluoromethane)
7,390
6,630
Decrease
[a] GWPs for combustion emissions (CH4, N2O) also have been revised in AR5. The facility-level CO2e calculations discussed later in this memorandum include the proposed changes to the GWPs for CH4 and N2O.
In addition to the GWP changes, EPA proposed several changes to subpart SS to improve the accuracy of emissions reported and enhance the overall quality of the data collected under the GHGRP (87 FR 36920, June 21, 2022). The changes were proposed because of the recent development of replacement insulating gases that have much lower GWPs than SF6 or PFCs. These replacement gases include dry air and F-GHGs. Table 4.16-2 lists the alternative gases currently available to manufacturers, the composition of the mixtures used, and their GWPs. Unlike SF6 which is used without dilution, the new F-GHGs are used in mixtures with CO2, oxygen, and/or nitrogen. The resulting GWP of the gas mixtures are significantly lower than SF6. In the last three years, several manufacturers have designed and begun marketing new products incorporating these alternative low GWP gases, while other manufacturers have developed products that use a vacuum or dry air mixture (see Table 4.16-2) as insulator. The F-GHGs have begun to be used in Europe and we expect their use to increase in the United States in future years. For this reason, the proposed amendments expand reporting to include emissions of any F-GHGs used by manufacturers. By collecting data on the types, composition and emissions of these new gases, EPA will gain a better understanding of emission trends and will be able to account for the total emissions from this sector.
Table 4.16-2. Composition of Alternative Gases Currently Available for Electric Equipment Manufacturers
                                Characteristics
                                    Dry Air
                               CF4-Fluoronitrile
                               CF5-Fluoroketone
Chemical Formula
N2 and O2
(CF3)2CFCN
(CF3)2CFC(O)CF3
100 Year GWP of Gas
0
2,100
<1
Typical Composition of Mixture
70  -  80% N2
20  -  30% O2
3  -  5% (CF3)2CFCN
95  -  97% CO2 and O2
10% (CF3)2CFC(O)CF3
90% mixture of O2 and N2, or CO2
100 Year GWP of Mixture
0
<500
<1

With the potential for alternate gases to become more widely used, EPA is proposing to revise the current applicability threshold to account for these lower GWP gases. As we previously noted, the current rule is applicable to a facility that purchases more than 23,000 pounds of combined SF6 and PFCs in a calendar year. This threshold is an "equivalent threshold" to the 25,000 mt CO2e threshold. This threshold was developed using the GWP of SF6 (set at 23,900 in 2010) and an emission factor of 10%. The 10% emission factor was based on the average of "ideal" and "realistic" manufacturing emission rates (4% and 17%, respectively) identified in a paper prepared by the International Council on Large Electric Systems (CIGRE) in February 2002. The proposal replaces the current applicability threshold with an equation that potential new reporters would use to calculate emissions from all F-GHGs by multiplying the total annual purchases of each insulating gas by the fraction of F-GHG in the insulating gas, the GWP for each F-GHG, and the emission factor of 0.10 (or 10%). The results would be summed for all F-GHGs used to calculate a total applicability CO2e for subpart SS. The proposed changes also include moving this source category to Table A-4 to subpart A, which will require the potential reporter to add the emissions from any fossil fuel-fired combustion units operated at their facility. If the total CO2e calculated exceeds 25,000 mt CO2e, the facility would become subject to the GHGRP beginning in the year they first exceed the reporting threshold.
The proposed revised applicability threshold is based on a new Equation SS-1, which accounts for the GWP of gases used and estimates potential emissions from the source. Under the proposed changes, combustion emissions would also be included in the facility emissions when determining whether a facility has exceeded the proposed 25,000 mt CO2e applicability threshold. The actual subpart SS emissions are calculated annually using a mass-balance equation provided in the rule and may be significantly lower than the applicability emissions where a facility has implemented emission reduction practices. The mass-balance approach used to calculate emissions is retained in the proposal, although the facility would be required to calculate and report emissions of other F-GHGs as discussed above.
4.16.1 Current Reporters
Subpart SS has two facilities currently in the process of off-ramping (i.e., below 25,000 mt CO2e for RY2020). For these facilities, we used their emissions from their last report to recalculate their CO2e using the AR5 GWPs. The recalculated CO2e was then compared with the 25,000 mt threshold. If the facility's recalculated CO2e exceeded 25,000 mt, then the facility would be required to continue reporting.
The CO2e for all facilities reporting under subpart SS were recalculated using the reported emissions for RY2020 and the new GWPs for SF6 and PFC-14. As no other gases have been reported under this subpart, these are the only changes in subpart SS CO2e that would result from the proposed adoption of the AR5 GWPs. Three of these facilities also report emissions under subpart C; the CO2e for the combustion emissions were also recalculated using the AR5 GWPs and included in the total facility-wide CO2e for each facility. The overall CO2e for each facility increased by between 461.8 and 2,304 mt, or 1.9 to 3.1%.
Of the five facilities reporting emissions under subpart SS in RY2020, two reported facility-wide CO2e of less than 25,000 mt CO2e (including combustion sources reported under subpart C). The reported and recalculated CO2e for these facilities (1006009 and 1009615) for the past five years are shown in Table 4.16-3.
     Table 4.16-3. Recalculated CO2e from Potential Off-Ramping Facilities
                                   Facility
                                      GWP
                                    RY2016
                                    RY2017
                                    RY2018
                                    RY2019
                                    RY2020
1006009
22,800
4,550
6,495
4,468
15,042
11,025

23,500
4,690
6,694
4,605
15,504
11,363
1009615
22,800
50,265
58,730
36,093
24,536
20,461

23,500
51,559
60,289
36,929
25,015
20,858

Based on the recalculated CO2e (including subpart C for the three facilities operating fossil fuel-fired combustion units), these facilities would still qualify to cease reporting and would not be required to recommence reporting in future years if their emissions remain consistent with those reported in RY2020. Facility 1009615 has only one year of CO2e less than 25,000 mt and will be required to report for at least three more years (four years if the next three years are between 15,000 and 24,999 mt CO2e). Based on internet research, it does not appear that facility 1009615 manufactures equipment using the new F-GHG insulating gases.
Facility 1006009 has reported five consecutive years of CO2e less than 25,000 mt and is currently eligible to cease reporting beginning in RY2021. This facility currently markets electric equipment using the new insulating gas CF5-fluoroketone discussed in Section 1.0. We do not know whether this facility emits CF5-fluoroketone. However, if they emit CF5-fluoroketone, we expect the CO2e contributed by the emissions of this F-GHG to be small relative to the CO2e from SF6 emissions because the GWP for CF5-fluoroketone is less than 1. Based on this facility's relatively low emissions (11,024 mt CO2e in RY2020) and the low GWP for CF5-fluoroketone, it is unlikely that the proposed reporting of CF5-fluoroketone emissions would cause this facility to exceed the 25,000 mt CO2e threshold that would require them to recommence reporting in the future if the proposed changes are adopted.
4.16.2 New Reporters
In this analysis, we determined the impact of the proposed use of AR5 GWPs and the proposed reporting of new F-GHGs for potential new reporters. We recalculated the CO2e for each facility that reported in RY2020 using the emissions they reported and the AR5 GWPs.
Subpart SS has one previous reporter that qualified to off-ramp from reporting in 2016. Like the facilities that are currently in the process of meeting the off-ramp provisions, we used the facility's emissions from their last report in 2016 to recalculate their CO2e using the AR5 GWPs. The recalculated CO2e was then compared with the 25,000 mt threshold. If the facility's recalculated CO2e exceeded 25,000 mt, then the facility would be required to begin reporting again.
Facility 1010764 last reported subpart SS emissions in RY2016 and reported only emissions of SF6. We recalculated the CO2e using the emissions reported in RY2016 and the AR5 GWP for SF6. The recalculated CO2e for this facility was 571 mt, thus the facility would not be required to begin reporting again if the AR5 GWP for SF6 is adopted. Based on our review of the company's website, it appears that they have developed SF6-free equipment using a mixture of nitrogen and oxygen. Since these gases are not greenhouse gases, we do not expect this facility will be required to recommence reporting due to the proposed changes.
We also evaluated whether the proposed changes would cause any new facility to begin reporting for the first time. To determine whether any new facilities would be required to report if the proposed changes are adopted, we used the proposed Equation SS-1 and the AR5 GWP for SF6 to calculate the CO2e for a facility using only SF6, purchasing 23,000 lbs of gas in a calendar year (i.e., the volume of gas used for the current applicability), and having no combustion units. We then assessed whether CO2e from combustion emissions and other F-GHGs, when added to the CO2e from SF6 would be likely to result in a facility-wide CO2e exceeding the proposed 25,000 mt applicability threshold. For the combustion emissions, we evaluated the CO2e reported by the three existing reporters that report under subparts C and SS to determine a typical range for the CO2e from combustions as a percentage of subpart SS CO2e.
Finally, we considered the impact of the new F-GHG insulating gases on applicability. We conducted internet searches to identify the alternative gases currently marketed. These gases are primarily being developed due to the high GWP of SF6. We used the National Electrical Manufacturers Association (NEMA) to identify manufacturers that currently market electrical equipment using one or more of the alternative gases listed in Table 4.16-2. NEMA has an SF6 alternatives coalition comprised of manufacturers, support companies, and utilities. Using this list of manufacturers, we researched their product lines to better understand the types of products companies are currently marketing. We then assessed whether companies using these other F-GHGs would be likely to become subject to subpart SS due to the proposed changes to the applicability criteria.
The potential for new facilities to be required to report under subpart SS due to the proposed revisions was also assessed. Using the proposed Equation SS-1, proposed GWP of 23,500 for SF6, and 23,000 lbs of purchased gas (the current applicability threshold), the estimated emissions calculated for comparison to the applicability threshold using Equation SS-1 are 24,517 mt CO2e. Thus, the current applicability threshold in this case is lower than the proposed applicability threshold.
A facility that has fossil fuel-fired combustion units would become subject to reporting if the CO2e from combustion emissions combined with the CO2e calculated using proposed Equation SS-1 exceeds 25,000 mt. Therefore, it is possible for a facility that has always purchased less than 23,000 lbs of SF6 and PFCs to become subject to the GHGRP due to the proposed changes. However, for existing subpart SS reporters, the combustion emissions are much smaller than the applicability emissions calculated using proposed Equation SS-1. Table 4.16-4 shows the calculated applicability emissions and combustion emissions for each of the three facilities that have combustion units. The CO2e values shown in Table 4.16-4 were calculated using the AR5 GWPs, purchase records reported under subpart SS, and subpart C emissions data reported in RY2020.
      Table 4.16-4. Applicability Emissions from Eq. SS-1 and Combustion
                                   Facility
                              Eq. SS-1
Emissions
                             Combustion Emissions
                 Combustion Emissions as Percent of Total CO2e
1009613
77,832
541
0.7
1009615
52,251
7,534
12.6
1000039
133,313
168
0.1

Considering the worst-case scenario of a facility with SF6 purchases that are currently just below the 23,000 lbs applicability threshold, the facility would need combustion emissions equivalent to 483 mt CO2e (approximately 2% of total CO2e) to be subject to the reporting rule if the proposed changes are adopted. While the CO2e from combustion sources can be as high as 12.6% of the total CO2e, the CO2e from combustion for two of the five subpart SS reporters accounts for less than 1% of their total CO2e. The two other subpart SS reporters have no combustion units. Compared with the other subpart SS facilities, combustion emissions reported by 1009615 are significantly higher than reported by other facilities in this sector and are likely not representative of this sector. While it is possible a facility could become subject to the GHGRP due the proposed GWP changes and inclusion of their combustion emissions, we consider it unlikely because (1) not all equipment manufactures operate fossil fuel-fired combustion units, and (2) those manufactures that operate fossil fuel-fired combustion units typically report relatively low-levels of combustion emissions.
Using the membership list for NEMA's SF6 alternatives coalition, we identified companies that manufacture electrical equipment. Based on internet research, a number of the companies we identified are in the process of developing and/or marketing equipment that uses alternative gases, including three who are currently not reporting under subpart SS. We assessed whether any of these companies may potentially become subject to subpart SS for the first time due to the proposed changes to the applicability criteria. We were not able to determine the amount of F-GHGs currently used by each company or confirm the company is using F-GHGs at their manufacturing facilities in the United States. However, all of these companies are also marketing equipment containing SF6.
Although the use of alternative gases, such as CF4-fluoronitrile and CF5-fluoroketone, is expected to increase over the next few years, we do not expect them to have a significant impact on the number of facilities required to report to the GHGRP over the next three years. First, the adoption of these new gases by utilities is likely to be slow due to the limited range of products currently marketed and the long lifetime of existing electrical equipment (typically over 40 years). Second, the alternative gases are used in dilute mixtures that have GWPs that are significantly lower than SF6. As we noted earlier, we know of two new F-GHGs that have begun to be used in electrical equipment. CF4-fluoronitrile has a GWP of 2,100 and CF5-fluoroketone has a GWP of less than 1. These F-GHGs are mixed with dry air, nitrogen, or CO2 to produce the insulating gas used in electric equipment, which reduces the GWP of the insulating gas as-used to less than 500 for dilute mixtures of CF4-fluoronitrile with CO2 and O2 and less than 1 for dilute mixtures of CF5-fluoroketone with O2 and nitrogen, or CO2. Assuming a 10% emission rate, a facility that uses 1 mt of SF6 would have emissions equivalent to 2,350 mt CO2e (based on a GWP of 23,500). A facility that uses a 5% solution of CF4-fluoronitrile would need to purchase 940 mt of gas to have emissions equivalent to 2,350 mt CO2e, assuming a GWP of 500 and the same 10% emission rate. Third, some of the companies we identified have developed products that rely on a vacuum or dry air as insulator.
For those manufacturers that are using CF4-fluoronitrile or CF5-fluoroketone in some of their products, we expect the combined effect of the small fraction of F-GHG used in each product, their inherently low GWPs compared with SF6, and the relatively low number of units currently manufactured to result in insignificant levels of CO2e compared with the CO2e for SF6 emissions. We expect the use of alternative F-GHGs will slowly increase over the next few years. Emissions of SF6 for many of the facilities in this sector may slowly decline as equipment using alternative insulating gases gradually gain market share.
 4.17 Subpart TT
40 CFR part 98 subpart TT (subpart TT) requires reporting of GHG emissions produced by industrial waste landfills that accept waste from various industry sectors. CO2 generated from waste decomposition is considered biogenic and N2O emissions generated for waste decomposition are negligible; thus, subpart TT requires facilities to report the generated CH4 emissions from industrial waste landfills.
For subpart TT, the GWP changes shown in Table 4.17-1 are expected to affect reported emissions:
Table 4.17-1. Applicable GWP Change for Subpart TT
                                      GHG
                                  Current GWP
                                    AR5 GWP
                                    Change
                                      CH4
                                      25
                                      28
                                   Increase

Subpart TT applies to industrial waste landfills that accepted waste on or after January 1, 1980, are located at a facility with a total landfill design capacity greater than or equal to 300,000 mt, and with combined emissions from all applicable subparts in the GHGRP of 25,000 mt CO2e or more per year. Most facilities report to subpart TT because their manufacturing emissions (e.g., process CO2 emissions) and/or combustion GHG emissions exceed 25,000 mt CO2e rather than their subpart TT emissions, that is, the magnitude of their subpart TT emissions does not influence whether they report or not. Therefore, the GHG emissions from the entire facility must be evaluated to determine the applicability of subpart TT for industrial waste landfills.
Because the GWP for CH4 is increasing, emissions at subpart TT facilities will have an overall increase. The approach to evaluating burden to subpart TT under the AR5 CH4 GWP revision is presented for:
 Facilities that met the off-ramp provisions in 40 CFR 98.2(i)(1) and 98.2(i)(2) as of RY2020,
 Facilities that are projected to cease reporting prior to RY2023 due to the off-ramp provisions, but are brought back into the program in RY2023 with the new AR5 CH4 GWP, and
 Facilities that are required to start reporting to the GHGRP for the first time after the GWP revision is adopted.
This analysis assumes that the AR5 CH4 GWP revision will be incorporated for RY2023 for active and off-ramped reporters and for RY2024 for new reporters. A summary of the industrial sector contributors to industrial landfill waste facilities is shown in Table 4.17-2.
Table 4.17-2. RY2020 Subpart TT Industrial Sector Contributors
              Type of Facility (from Reported Primary NAICS Code)
                           All Subparts Reported To
                Included/Excluded within the Burden Evaluation
                       Number of TT Reporting Facilities
                              Paper Manufacturing
                               C, AA, II, PP, TT
                                   Excluded
                                      88
                         Waste Treatment and Disposal
                                   C, HH, TT
                                   Included
                                      15
                            Chemical Manufacturing
                              C, D, L, X, OO, TT
                                   Excluded
                                       8
                 Sugar and Confectionery Product Manufacturing
                                   C, S, TT
                                   Excluded
                                       8
                                   Foundries
                                   C, N, TT
                                   Excluded
                                       7
               Iron and Steel Mills and Ferroalloy Manufacturing
                                   C, Q, TT
                                   Excluded
                                       6
Resin, Synthetic Rubber, and Artificial and Synthetic Fibers and Filaments Manufacturing
                               C, E, P, V, X, TT
                                   Excluded
                                       5
           Electric Power Generation, Transmission, and Distribution
                                   C, D, TT
                                   Excluded
                                       5
                Alumina and Aluminum Production and Processing
                                   C, F, TT
                                   Excluded
                                       5
                   Petroleum and Coal Products Manufacturing
                                C, P, Y, MM, TT
                                   Excluded
                                       4
                                  Paper Mills
                                   C, AA, TT
                                   Excluded
                                       3
                              Food Manufacturing
                                     C, TT
                                   Included
                                       3
                         Basic Chemical Manufacturing
                              C, O, W, X, DD, TT
                                   Excluded
                                       3
                               Metal Ore Mining
                                     C, TT
                                   Included
                                       1
          Veneer, Plywood, and Engineered Wood Product Manufacturing
                                     C, TT
                                   Included
                                       1
                            Beverage Manufacturing
                                     C, TT
                                   Included
                                       1
                               Sugarcane Farming
                                     C, TT
                                   Included
                                       1
                             Forging and Stamping
                                     C, TT
                                   Included
                                       1
                   Pharmaceutical and Medicine Manufacturing
                                     C, TT
                                   Included
                                       1

We determined that the AR5 CH4 GWP change will not significantly change emissions, or the reporting applicability of the facility types listed as "Excluded" in Table 4.17-2. Industrial waste landfills are generally co-located at facilities that report to the GHGRP due to meeting other subpart-specific reporting criteria and are primarily driven by process level CO2 emissions and/or combustion emissions from other subparts. The AR5 CH4 GWP increase for subpart C (and any other subparts using subpart C combustion factors) was determined to be offset by the AR5 N2O decrease, resulting in negligible changes in subpart C emissions (and combustion in other subparts using the C methodology) as discussed in Section 2.2.
CH4 emissions increases from subpart TT sources at facilities listed as "Excluded" in Table 4.17-2 were reviewed and determined to be negligible, as these facilities emissions are driven by other industrial activities. This analysis assumes that no new reporters will enter the GHGRP from these industrial categories because of the AR5 CH4 GWP change in subpart TT. For these industrial sectors, the burden analysis was limited to evaluating the impacts to facilities that have already ceased reporting, or that are projected to cease reporting due to the off-ramp provisions.
For the remaining TT industrial categories (i.e., those listed as "Included" in Table 4.17-2), an analysis was performed to estimate the number of facilities expected to start reporting for the first time, as well as the impacts to off-ramped (including those projected to) facilities.
There are 55 facilities reporting RY2020 subpart TT emissions after omitting facilities that are listed as "Excluded" in Table 4.17-2. Of the 55 facilities, 47 facilities reported facility emissions above 25,000 mt CO2e, and the remaining 8 reported facility emissions below 25,000 mt CO2e. Since the AR5 CH4 GWP revision will result in emissions increases under subpart TT, the 47 facilities reporting above 25,000 mt CO2e will be unaffected by these changes. The remaining 8 were further evaluated, as discussed below.
4.17.1 Current Reporters
For this analysis, projected off-ramp facilities are defined as those that are assumed to cease reporting prior to RY2023. To determine this group of facilities, RY2021 and RY2022 emissions were estimated using past reported data for applicable subpart TT facilities. Additionally, the variability of prior year data was reviewed to determine if emissions were consistent or inconsistent. For cases where prior year (RY2016 - RY2020) emissions were consistently below the off-ramp provisions in 40 CFR 98.2(i)(1) and 98.2(i)(2) and the facility is eligible to cease reporting for the first time in either RY2021 or RY2022, it was assumed that these facilities will cease reporting prior to RY2023. This subset of facilities was then evaluated to determine if the subpart TT CH4 GWP increase in RY2023 would raise emissions over the 25,000 mt CO2e threshold. If this is true, then the facility was assumed to incur burden because they would be brought back into the program.
Of the eight facilities with existing emissions below 25,000 mt CO2e, four facilities were projected to off-ramp prior to RY2023 because their facility emissions were consistent over the past five years, and they will be off-ramp eligible for the first time prior to RY2023 (as defined above). The AR5 CH4 GWP was applied to these four facilities, and it was determined through re-calculations that the four facilities would not be brought back into the program because the recalculated emissions will not exceed the 25,000 mt CO2e threshold. The other four facilities are still projected to report to the GHGRP as they are not eligible to off-ramp prior to RY2023. Thus, there is no change to the number of affected facilities for subpart TT.
4.17.2 New Reporters
<IP_ADDRESS> Analyses of Previously Off-Ramped Facilities
Subpart TT facilities that have already ceased reporting due to the off-ramp provisions between RY2014 to RY2020 were also evaluated. The AR5 CH4 GWP revision was applied to all previously off-ramped subpart TT facilities (using last reported facility emissions) to determine their assumed change in emissions. A burden increase was assumed if a facility's emissions went above the 25,000 mt CO2e threshold under the updated AR5 CH4 GWP.
Table 4.17-3 highlights the off-ramped reporting facilities' last reported emissions using the current and revised GWP values. It was determined that there are no previously off-ramped reporters that will need to start reporting again because of the GWP changes.
Table 4.17-3. Impact on Subpart TT Off-Ramp RY CO2e Emissions
                                  Facility ID
                                  Off-Ramp RY
               Subpart TT CO2e Emissions Reported in Off-Ramp RY
                Facility CO2e Emissions Reported in Off-Ramp RY
                 Revised Facility CO2e Emissions Under AR5 GWP
                                    1006522
                                     2014
                                     1,084
                                     1,084
                                     1,214
                                    1010668
                                     2014
                                    10,909
                                    10,909
                                    12,218
                                    1006679
                                     2015
                                     2,362
                                     2,362
                                     2,645
                                    1008069
                                     2015
                                     8,698
                                     8,698
                                     9,742
                                    1009526
                                     2017
                                     3,876
                                     4,776
                                     5,242
                                    1009824
                                     2017
                                    20,389
                                    20,389
                                    22,835

<IP_ADDRESS> Analyses of Non-Reporters Entering the GHGRP
Since very little data exists to estimate the population of facilities that may be required to start reporting to the GHGRP for the first time after the GWP revision is adopted, reporter burden was determined by reviewing the number of new reporters that entered the program in RY2014 following the promulgation of a new CH4 GWP in RY2013 (GWP was revised from 21 to 25). In RY2014, there was a 19% increase in the GWP (GWP revised from 21 to 25) and there were also three new subpart TT reporters (see Table 4.17-4). This analysis assumes that a relative increase in facilities will also occur in RY2024 following a 12% increase (GWP revised from 25 to 28) in the CH4 GWP factor.
The three new facilities were further evaluated to determine which ones likely entered the program due to the 2013 GWP revisions. It is likely that facility 1009526 started reporting subpart TT emissions to the GHGRP in RY2014 due to the 2013 GWP increase. Facility 1011501 started reporting in RY2014 because of a change in landfill ownership. It was not clear why facility 1011740 started reporting but based on the total facility emissions and the contribution of TT, it is unlikely that this facility started reporting due to the GWP increase. As such, it is assumed that one new facility started reporting due to the 2013 GWP revisions.
A 12% increase in CH4 emissions following the AR5 CH4 GWP revision is expected to result in one additional facility reporting to subpart TT in RY2024. This was determined by ratioing the number of new reporters in RY2014 (one new reporter was assumed to enter the program from the 19% increase in the GWP in RY2014) to the percent increase in RY2024 of 12% (GWP changing from 25 to 28).
Table 4.17-4. Subpart TT RY2014 New Reporting Facilities with CO2e Emissions
                                   GHGRP ID
              Type of Facility (from Reported Primary NAICS Code)
                   RY2014 Reported Subpart TT CO2e Emissions
                    RY2014 Reported Facility CO2e Emissions
1011501
Waste Treatment and Disposal
353,145
353,153
1011740
Pharmaceutical and Medicine Manufacturing
14,925
50,307
1009526
All Other Electrical Equipment and Component Manufacturing
4,289
28,156

 Appendix A: Proposed Revised Chemical-Specific GWPs for Compounds in Table A-1
                                     Name
                                    CAS No.
                               Chemical Formula
                  Current Global
Warming
Potential
(100 Yr.)
                  Proposed Global
Warming
Potential
(100 Yr.)
                            Chemical-Specific GWPs
Carbon dioxide
124-38-9
CO2
1
1
Methane
74-82-8
CH4
25
28
Nitrous oxide
10024-97-2
N2O
298
265
                            Fully Fluorinated GHGs
Sulfur hexafluoride
2551-62-4
SF6
22,800
23,500
Trifluoromethyl sulfur pentafluoride
373-80-8
SF5CF3
17,700
17,400
Nitrogen trifluoride
7783-54-2
NF3
17,200
16,100
PFC-14 (Perfluoromethane)
75-73-0
CF4
7,390
6,630
PFC-116 (Perfluoroethane)
76-16-4
C2F6
12,200
11,100
PFC-218 (Perfluoropropane)
76-19-7
C3F8
8,830
8,900
Perfluorocyclopropane
931-91-9
c-C3F6
17,340
9,200
PFC-3-1-10 (Perfluorobutane)
355-25-9
C4F10
8,860
9,200
PFC-318 (Perfluorocyclobutane)
115-25-3
c-C4F8
10,300
9,540
Perfluorotetrahydrofuran
773-14-8
c-C4F8O
10,000*
13,900
PFC-4-1-12 (Perfluoropentane)
678-26-2
C5F12
9,160
8,550
PFC-5-1-14 (Perfluorohexane, FC-72)
355-42-0
C6F14
9,300
7,910
PFC-6-1-12
335-57-9
C7F16; CF3(CF2)5CF3
7,820
7,820
PFC-7-1-18
307-34-6
C8F18; CF3(CF2)6CF3
7,620
7,620
PFC-9-1-18
306-94-5
C10F18
7,500
7,190
PFPMIE (HT-70)
NA
CF3OCF(CF3)CF2OCF2OCF3
10,300
9,710
Perfluorodecalin (cis)
60433-11-6
Z-C10F18
7,236
7,240
Perfluorodecalin (trans)
60433-12-7
E-C10F18
6,288
6,290
Perfluorotriethylamine
359-70-6
N(C2F5)3
10,000*
10,300
Perfluorotripropylamine
338-83-0
N(CF2CF2CF3)3
10,000*
9,030
Perfluorotributylamine
311-89-7
N(CF2CF2CF2CF3)3
10,000*
8,490
Perfluorotripentylamine
338-84-1
N(CF2CF2CF2CF2CF3)3
10,000*
7,260
  Saturated Hydrofluorocarbons (HFCs) With Two or Fewer Carbon-Hydrogen Bonds
(4s,5s)-1,1,2,2,3,3,4,5-octafluorocyclopentane
158389-18-5
trans-cyc (-CF2CF2CF2CHFCHF-)
3,700*
258
HFC-23
75-46-7
CHF3
14,800
12,400
HFC-32
75-10-5
CH2F2
675
677
HFC-125
354-33-6
C2HF5
3,500
3,170
HFC-134
359-35-3
C2H2F4
1,100
1,120
HFC-134a
811-97-2
CH2FCF3
1,430
1,300
HFC-227ca
2252-84-8
CF3CF2CHF2
2,640
2,640
HFC-227ea
431-89-0
C3HF7
3,220
3,350
HFC-236cb
677-56-5
CH2FCF2CF3
1,340
1,210
HFC-236ea
431-63-0
CHF2CHFCF3
1,370
1,330
HFC-236fa
690-39-1
C3H2F6
9,810
8,060
HFC-329p
375-17-7
CHF2CF2CF2CF3
2,360
2,360
HFC-43-10mee
138495-42-8
CF3CFHCFHCF2CF3
1,640
1,650
 Saturated Hydrofluorocarbons (HFCs) With Three or More Carbon-Hydrogen Bonds
1,1,2,2,3,3-hexafluorocyclopentane
123768-18-3
cyc (-CF2CF2CF2CH2CH2-)
930*
120
1,1,2,2,3,3,4-heptafluorocyclopentane
15290-77-4
cyc (-CF2CF2CF2CHFCH2-)
930*
231
HFC-41
593-53-3
CH3F
92
116
HFC-143
430-66-0
C2H3F3
353
328
HFC-143a
420-46-2
C2H3F3
4,470
4,800
HFC-152
624-72-6
CH2FCH2F
53
16
HFC-152a
75-37-6
CH3CHF2
124
138
HFC-161
353-36-6
CH3CH2F
12
4
HFC-245ca
679-86-7
C3H3F5
693
716
HFC-245cb
1814-88-6
CF3CF2CH3
4,620
4,620
HFC-245ea
24270-66-4
CHF2CHFCHF2
235
235
HFC-245eb
431-31-2
CH2FCHFCF3
290
290
HFC-245fa
460-73-1
CHF2CH2CF3
1,030
858
HFC-263fb
421-07-8
CH3CH2CF3
76
76
HFC-272ca
420-45-1
CH3CF2CH3
144
144
HFC-365mfc
406-58-6
CH3CF2CH2CF3
794
804
Saturated Hydrofluoroethers (HFEs) and Hydrochlorofluoroethers (HCFEs) With One Carbon-Hydrogen Bond
HFE-125
3822-68-2
CHF2OCF3
14,900
12,400
HFE-227ea
2356-62-9
CF3CHFOCF3
1,540
6,450
HFE-329mcc2
134769-21-4
CF3CF2OCF2CHF2
919
3,070
HFE-329me3
428454-68-6
CF3CFHCF2OCF3
4,550
4,550
1,1,1,2,2,3,3-Heptafluoro-3-(1,2,2,2-tetrafluoroethoxy)-propane
3330-15-2
CF3CF2CF2OCHFCF3
6,490
6,490
            Saturated HFEs and HCFEs With Two Carbon-Hydrogen Bonds
HFE-134 (HG-00)
1691-17-4
CHF2OCHF2
6,320
5,560
HFE-236ca
32778-11-3
CHF2OCF2CHF2
4,240
4,240
HFE-236ca12 (HG-10)
78522-47-1
CHF2OCF2OCHF2
2,800
5,350
HFE-236ea2 (Desflurane)
57041-67-5
CHF2OCHFCF3
989
1,790
HFE-236fa
20193-67-3
CF3CH2OCF3
487
979
HFE-338mcf2
156053-88-2
CF3CF2OCH2CF3
552
929
HFE-338mmz1
26103-08-2
CHF2OCH(CF3)2
380
2,620
HFE-338pcc13 (HG-01)
188690-78-0
CHF2OCF2CF2OCHF2
1,500
2,910
HFE-43-10pccc (H-Galden 1040x, HG-11)
E1730133
CHF2OCF2OC2F4OCHF2
1,870
2,820
HCFE-235ca2 (Enflurane)
13838-16-9
CHF2OCF2CHFCl
583
583
HCFE-235da2 (Isoflurane)
26675-46-7
CHF2OCHClCF3
350
491
HG-02
205367-61-9
HF2C-(OCF2CF2)2-OCF2H
3,825
2,730
HG-03
173350-37-3
HF2C-(OCF2CF2)3-OCF2H
3,670
2,850
HG-20
249932-25-0
HF2C-(OCF2)2-OCF2H
5,300
5,300
HG-21
249932-26-1
HF2C-OCF2CF2OCF2OCF2O-CF2H
3,890
3,890
HG-30
188690-77-9
HF2C-(OCF2)3-OCF2H
7,330
7,330
1,1,3,3,4,4,6,6,7,7,9,9,10,10,12,12,13,13,15,15-eicosafluoro-2,5,8,11,14-Pentaoxapentadecane
173350-38-4
HCF2O(CF2CF2O)4CF2H
3,630
3,630
1,1,2-Trifluoro-2-(trifluoromethoxy)-ethane
84011-06-3
CHF2CHFOCF3
1,240
1,240
Trifluoro(fluoromethoxy)methane
2261-01-0
CH2FOCF3
751
751
       Saturated HFEs and HCFEs With Three or More Carbon-Hydrogen Bonds
HFE-143a
421-14-7
CH3OCF3
756
523
HFE-245cb2
22410-44-2
CH3OCF2CF3
708
654
HFE-245fa1
84011-15-4
CHF2CH2OCF3
286
828
HFE-245fa2
1885-48-9
CHF2OCH2CF3
659
812
HFE-254cb2
425-88-7
CH3OCF2CHF2
359
301
HFE-263fb2
460-43-5
CF3CH2OCH3
11
1
HFE-263m1; R-E-143a
690-22-2
CF3OCH2CH3
29
		29
HFE-347mcc3 (HFE-7000)
375-03-1
CH3OCF2CF2CF3
575
530
HFE-347mcf2
171182-95-9
CF3CF2OCH2CHF2
374
854
HFE-347mmy1
22052-84-2
CH3OCF(CF3)2
343
363
HFE-347mmz1 (Sevoflurane)
28523-86-6
(CF3)2CHOCH2F
216
216
HFE-347pcf2
406-78-0
CHF2CF2OCH2CF3
580
889
HFE-356mec3
382-34-3
CH3OCF2CHFCF3
101
387
HFE-356mff2
333-36-8
CF3CH2OCH2CF3
17
17
HFE-356mmz1
13171-18-1
(CF3)2CHOCH3
27
14
HFE-356pcc3
160620-20-2
CH3OCF2CF2CHF2
110
413
HFE-356pcf2
50807-77-7
CHF2CH2OCF2CHF2
265
719
HFE-356pcf3
35042-99-0
CHF2OCH2CF2CHF2
502
446
HFE-365mcf2
22052-81-9
CF3CF2OCH2CH3
58
58
HFE-365mcf3
378-16-5
CF3CF2CH2OCH3
11
0.99
HFE-374pc2
512-51-6
CH3CH2OCF2CHF2
557
627
HFE-449s1 (HFE-7100) Chemical blend
163702-07-6
C4F9OCH3
297
421

163702-08-7
(CF3)2CFCF2OCH3

HFE-569sf2 (HFE-7200) Chemical blend
163702-05-4
C4F9OC2H5
59
57

163702-06-5
(CF3)2CFCF2OC2H5

HFE-7300
132182-92-4
(CF3)2CFCFOC2H5CF2CF2CF3
270*
405
HFE-7500
297730-93-9
n-C3F7CFOC2H5CF(CF3)2
270*
13
HG'-01
73287-23-7
CH3OCF2CF2OCH3
222
222
HG'-02
485399-46-0
CH3O(CF2CF2O)2CH3
236
236
HG'-03
485399-48-2
CH3O(CF2CF2O)3CH3
221
221
Difluoro(methoxy)methane
359-15-9
CH3OCHF2
144
144
2-Chloro-1,1,2-trifluoro-1-methoxyethane
425-87-6
CH3OCF2CHFCl
122
122
1-Ethoxy-1,1,2,2,3,3,3-heptafluoropropane
22052-86-4
CF3CF2CF2OCH2CH3
61
61
2-Ethoxy-3,3,4,4,5-pentafluorotetrahydro-2,5-bis[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]-furan
920979-28-8
C12H5F19O2
56
56
1-Ethoxy-1,1,2,3,3,3-hexafluoropropane
380-34-7
CF3CHFCF2OCH2CH3
23
23
Fluoro(methoxy)methane
460-22-0
CH3OCH2F
13
13
1,1,2,2-Tetrafluoro-3-methoxy-propane; Methyl 2,2,3,3-tetrafluoropropyl ether
60598-17-6
CHF2CF2CH2OCH3
0.5
0.49
1,1,2,2-Tetrafluoro-1-(fluoromethoxy)ethane
37031-31-5
CH2FOCF2CF2H
871
871
Difluoro(fluoromethoxy)methane
461-63-2
CH2FOCHF2
617
617
Fluoro(fluoromethoxy)methane
462-51-1
CH2FOCH2F
130
130
                     Saturated Chlorofluorocarbons (CFCs)
E-R316c
3832-15-3
trans-cyc (-CClFCF2CF2CClF-)
2000*
4,230
Z-R316c
3934-26-7
cis-cyc (-CClFCF2CF2CClF-)
2000*
5,660
                             Fluorinated Formates
Trifluoromethyl formate
85358-65-2
HCOOCF3
588
588
Perfluoroethyl formate
313064-40-3
HCOOCF2CF3
580
580
1,2,2,2-Tetrafluoroethyl formate
481631-19-0
HCOOCHFCF3
470
470
Perfluorobutyl formate
197218-56-7
HCOOCF2CF2CF2CF3
392
392
Perfluoropropyl formate
271257-42-2
HCOOCF2CF2CF3
376
376
1,1,1,3,3,3-Hexafluoropropan-2-yl formate
856766-70-6
HCOOCH(CF3)2
333
333
2,2,2-Trifluoroethyl formate
32042-38-9
HCOOCH2CF3
33
33
3,3,3-Trifluoropropyl formate
1344118-09-7
HCOOCH2CH2CF3
17
17
                             Fluorinated Acetates
Methyl 2,2,2-trifluoroacetate
431-47-0
CF3COOCH3
52
52
1,1-Difluoroethyl 2,2,2-trifluoroacetate
1344118-13-3
CF3COOCF2CH3
31
31
Difluoromethyl 2,2,2-trifluoroacetate
2024-86-4
CF3COOCHF2
27
27
2,2,2-Trifluoroethyl 2,2,2-trifluoroacetate
407-38-5
CF3COOCH2CF3
7
7
Methyl 2,2-difluoroacetate
433-53-4
HCF2COOCH3
3
3
Perfluoroethyl acetate
343269-97-6
CH3COOCF2CF3
2.1
2
Trifluoromethyl acetate
74123-20-9
CH3COOCF3
2.0
2
Perfluoropropyl acetate
1344118-10-0
CH3COOCF2CF2CF3
1.8
2
Perfluorobutyl acetate
209597-28-4
CH3COOCF2CF2CF2CF3
1.6
2
Ethyl 2,2,2-trifluoroacetate
383-63-1
CF3COOCH2CH3
1.3
1
                              Carbonofluoridates
Methyl carbonofluoridate
1538-06-3
FCOOCH3
95
95
1,1-Difluoroethyl carbonofluoridate
1344118-11-1
FCOOCF2CH3
27
27
            Fluorinated Alcohols Other Than Fluorotelomer Alcohols
Bis(trifluoromethyl)-methanol
920-66-1
(CF3)2CHOH
195
182
2,2,3,3,4,4,5,5-Octafluorocyclopentanol
16621-87-7
cyc (-(CF2)4CH(OH)-)
73
13
2,2,3,3,3-Pentafluoropropanol
422-05-9
CF3CF2CH2OH
42
19
2,2,3,3,4,4,4-Heptafluorobutan-1-ol
375-01-9
C3F7CH2OH
25
34
2,2,2-Trifluoroethanol
75-89-8
CF3CH2OH
20
20
2,2,3,4,4,4-Hexafluoro-1-butanol
382-31-0
CF3CHFCF2CH2OH
17
17
2,2,3,3-Tetrafluoro-1-propanol
76-37-9
CHF2CF2CH2OH
13
13
2,2-Difluoroethanol
359-13-7
CHF2CH2OH
3
3
2-Fluoroethanol
371-62-0
CH2FCH2OH
1.1
1.1
4,4,4-Trifluorobutan-1-ol
461-18-7
CF3(CH2)2CH2OH
0.05
0.05
                Non-Cyclic, Unsaturated Perfluorocarbons (PFCs)
PFC-1114; TFE
116-14-3
CF2=CF2; C2F4
0.004
0.004
PFC-1216; Dyneon HFP
116-15-4
C3F6; CF3CF=CF2
0.05
0.05
Perfluorobut-2-ene
360-89-4
CF3CF=CFCF3
1.82
2
Perfluorobut-1-ene
357-26-6
CF3CF2CF=CF2
0.10
0.10
Perfluorobuta-1,3-diene
685-63-2
CF2=CFCF=CF2
0.003
0.003
Non-Cyclic, Unsaturated Hydrofluorocarbons (HFCs) and Hydrochlorofluorocarbons (HCFCs)
HFC-1132a; VF2
75-38-7
C2H2F2, CF2=CH2
0.04
0.04
HFC-1141; VF
75-02-5
C2H3F, CH2=CHF
0.02
0.02
(E)-HFC-1225ye
5595-10-8
CF3CF=CHF(E)
0.06
0.06
(Z)-HFC-1225ye
5528-43-8
CF3CF=CHF(Z)
0.22
0.22
Solstice 1233zd(E)
102687-65-0
C3H2ClF3; CHCl=CHCF3
1.34
1
HCFO-1233zd(Z)
99728-16-2
(Z)-CF3CH=CHCl
1*
0.45
HFC-1234yf; HFO-1234yf
754-12-1
C3H2F4; CF3CF=CH2
0.31
0.31
HFC-1234ze(E)
1645-83-6
C3H2F4; trans-CF3CH=CHF
0.97
0.97
HFC-1234ze(Z)
29118-25-0
C3H2F4; cis-CF3CH=CHF; CF3CH=CHF
0.29
0.29
HFC-1243zf; TFP
677-21-4
C3H3F3, CF3CH=CH2
0.12
0.12
(Z)-HFC-1336
692-49-9
CF3CH=CHCF3(Z)
1.58
2
HFO-1336mzz(E)
66711-86-2
(E)-CF3CH=CHCF3
1*
18
HFC-1345zfc
374-27-6
C2F5CH=CH2
0.09
0.09
HFO-1123
359-11-5
CHF=CF2
1*
0.005
HFO-1438ezy(E)
14149-41-8
(E)-(CF3)2CFCH=CHF
1*
8.2
HFO-1447fz
355-08-8
CF3(CF2)2CH=CH2
1*
0.24
Capstone 42-U
19430-93-4
C6H3F9, CF3(CF2)3CH=CH2
0.16
0.16
Capstone 62-U
25291-17-2
C8H3F13, CF3(CF2)5CH=CH2
0.11
0.11
Capstone 82-U
21652-58-4
C10H3F17, CF3(CF2)7CH=CH2
0.09
0.09
(e)-1-chloro-2-fluoroethene
460-16-2
(E)-CHCl=CHF
1*
0.004
3,3,3-trifluoro-2-(trifluoromethyl)prop-1-ene
382-10-5
(CF3)2C=CH2
1*
0.38
                         Non-Cyclic, Unsaturated CFCs
CFC-1112
598-88-9
CClF=CClF
1*
0.13
CFC-1112a
79-35-6
CCl2=CF2
1*
0.021
                  Non-Cyclic, Unsaturated Halogenated Ethers
PMVE; HFE-216
1187-93-5
CF3OCF=CF2
0.17
0.17
Fluoroxene
406-90-6
CF3CH2OCH=CH2
0.05
0.05
Methyl-perfluoroheptene-ethers
N/A
CH3OC7F13
1*
15
                  Non-Cyclic, Unsaturated Halogenated Esters
Ethenyl 2,2,2-trifluoroacetate
433-28-3
CF3COOCH=CH2
1*
0.008
Prop-2-enyl 2,2,2-trifluoroacetate
383-67-5
CF3COOCH2CH=CH2
1*
0.007
                       Cyclic, Unsaturated HFCs and PFCs
PFC C-1418
559-40-0
c-C5F8
1.97
2
Hexafluorocyclobutene
697-11-0
cyc (-CF=CFCF2CF2-)
1*
126
1,3,3,4,4,5,5-heptafluorocyclopentene
1892-03-1
cyc (-CF2CF2CF2CF=CH-)
1*
45
1,3,3,4,4-pentafluorocyclobutene
374-31-2
cyc (-CH=CFCF2CF2-)
1*
92
3,3,4,4-tetrafluorocyclobutene
2714-38-7
cyc (-CH=CHCF2CF2-)
1*
26
                             Fluorinated Aldehydes
3,3,3-Trifluoro-propanal
460-40-2
CF3CH2CHO
0.01
0.01
                              Fluorinated Ketones
Novec 1230 (perfluoro (2-methyl-3-pentanone))
756-13-8
CF3CF2C(O)CF(CF3)2
0.1
0.11
1,1,1-trifluoropropan-2-one
421-50-1
CF3COCH3
1*
0.09
1,1,1-trifluorobutan-2-one
381-88-4
CF3COCH2CH3
1*
0.095
                            Fluorotelomer Alcohols
3,3,4,4,5,5,6,6,7,7,7-Undecafluoroheptan-1-ol
185689-57-0
CF3(CF2)4CH2CH2OH
0.43
0.43
3,3,3-Trifluoropropan-1-ol
2240-88-2
CF3CH2CH2OH
0.35
0.35
3,3,4,4,5,5,6,6,7,7,8,8,9,9,9-Pentadecafluorononan-1-ol
755-02-2
CF3(CF2)6CH2CH2OH
0.33
0.33
3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-Nonadecafluoroundecan-1-ol
87017-97-8
CF3(CF2)8CH2CH2OH
0.19
0.19
                  Fluorinated GHGs With Carbon-Iodine Bond(s)
Trifluoroiodomethane
2314-97-8
CF3I
0.4
0.4
            Remaining Fluorinated GHGs with Chemical-Specific GWPs
Dibromodifluoromethane (Halon 1202)
75-61-6
CBr2F2
231
231
2-Bromo-2-chloro-1,1,1-trifluoroethane (Halon-2311/Halothane)
151-67-7
CHBrClCF3
41
41
Heptafluoroisobutyronitrile
42532-60-5
(CF3)2CFCN
2000*
2,750
Carbonyl fluoride
353-50-4
COF2
2000*
0.14**
*Table A-1 does not include a chemical-specific value for this GHG; the value shown is the current default GWP for the fluorinated GHG group of which the GHG is currently a member.
**Proposed in 2022 Data Quality Improvements Proposal.
 Appendix B: Proposed Fluorinated GHG Groups and Default GWPs
                             Fluorinated GHG Group
                  Current Global Warming Potential (100 Yr.)
                  Proposed Global Warming Potential (100 Yr.)
Fully fluorinated GHGs
10,000
9,200
Saturated hydrofluorocarbons (HFCs) with two or fewer carbon-hydrogen bonds
3,700
3,000
Saturated HFCs with three or more carbon-hydrogen bonds
930
840
Saturated hydrofluoroethers (HFEs) and hydrochlorofluoroethers (HCFEs) with one carbon-hydrogen bond
5,700
6,600
Saturated HFEs and HCFEs with two carbon-hydrogen bonds
2,600
2,900
Saturated HFEs and HCFEs with three or more carbon-hydrogen bonds
270
320
Saturated chlorofluorocarbons (CFCs)
2,000*
4,900
Fluorinated formates
350
350
Cyclic forms of the following: unsaturated perfluorocarbons (PFCs), unsaturated HFCs, unsaturated CFCs, unsaturated hydrochlorofluorocarbons (HCFCs), unsaturated bromofluorocarbons (BFCs), unsaturated bromochlorofluorocarbons (BCFCs), unsaturated hydrobromofluorocarbons (HBFCs), unsaturated hydrobromochlorofluorocarbons (HBCFCs), unsaturated halogenated ethers, and unsaturated halogenated esters
1**
58
Fluorinated acetates, carbonofluoridates, and fluorinated alcohols other than fluorotelomer alcohols
30
25
Fluorinated aldehydes, fluorinated ketones, and non-cyclic forms of the following: unsaturated PFCs, unsaturated HFCs, unsaturated CFCs, unsaturated HCFCs, unsaturated BFCs, unsaturated BCFCs, unsaturated HBFCs, unsaturated HBCFCs, unsaturated halogenated ethers, and unsaturated halogenated esters
1
1
Fluorotelomer alcohols
1
1
Fluorinated GHGs with carbon-iodine bond(s)
1
1
Remaining fluorinated GHGs
2,000
1,800
*Based on current classification as "Other fluorinated GHGs"
**Based on current classification as "Unsaturated perfluorocarbons (PFCs), unsaturated HFCs, unsaturated hydrochlorofluorocarbons (HCFCs), unsaturated halogenated ethers, unsaturated halogenated esters"