1

Summary of Methodology and Data Used to 

Evaluate Resource Requirements at Alternative Greenhouse Gas (GHG) 

Permitting Thresholds 

December 2011 

1. Introduction 

This paper summarizes an assessment of the estimated resource requirements for 

permitting authorities to include greenhouse gases (GHGs) at several possible major source 

permitting thresholds in the title V and Prevention of Significant Deterioration (PSD) permitting 

programs. The initial analysis was conducted to support the Tailoring Rule, resulting in a 

Technical Support Document (TSD) found at EPA-HQ-OAR-2009-0517.1

 Utilizing the Tailoring 

Rule TSD as a starting point, this analysis examines burden impacts at five additional thresholds 

between 50,000 and 100,000 tons per year (tpy) carbon dioxide equivalent (CO2e). As before, the 

analysis was performed considering GHG emissions on a CO2e-basis, which represents the sum 

of the six primary GHGs with their respective global warming potentials (GWP) applied. Time 

and costs associated with permit activities are derived from existing Information Collection 

Requests (ICRs) for the title V and PSD programs. Estimates for the number of affected sources 

used in this analysis were obtained from the additional GHG thresholds evaluation, which can be 

found at EPA-HQ-OAR-2009-0517.2

 

1

 “Summary of Methodology and Data Used to Estimate Burden Relief and Evaluate Resource Requirements at 

Alternative Greenhouse Gas (GHG) Permitting Thresholds;” Prepared by EPA Staff; March 2010. 2

 “Technical Support Document: Additional Threshold Analysis Greenhouse Gas Tailoring Rule,” October 12, 

2011. 
2

2. Methodology for Estimating Permitting Burden Due to GHG Emission Sources 

This section describes the basic methodology used to estimate the different types and 

quantities of permitting actions that would be affected by altering the threshold levels for GHGs 

under the PSD and title V permitting programs. Final burden results summarized in Section 3 are 

based on the methodologies described in this section. In developing our methodology for the 

Tailoring Rule and future rulemaking, we examined different applicability options under which 

GHG emission sources would be regulated. These GHG applicability thresholds range from the 

thresholds established for Step 2 of the Tailoring Rule (100,000 tpy CO2e for new major sources 

and 75,000 tpy CO2e significance threshold for major modifications)3 to 50,000 tpy CO2e for 

both, as we indicated that no source with emissions below 50,000 tpy CO2e and no modification 

resulting in a net GHG increase of less than 50,000 tpy CO2e will be subject to PSD or title V 

permitting before April 30, 2016.4

 

PSD Permits 

Table 2-1 summarizes EPA’s estimate of modifications and new construction PSD 

permitting actions potentially affected by the addition of GHG as a regulated air pollutant at 

different thresholds. These actions are broken down by type of modification and new 

construction activity. Three types of modifications are included in this analysis: major 

modifications at major sources that are triggered by increased conventional pollutant emissions, 

 

3

 Step 2 of the Tailoring Rule, which began on July 1, 2011, continued Step 1 and applied PSD and title V to new 

sources as well as existing sources that are not “anyway” sources and that emit, or have the potential to emit, at least 

100,000 tpy CO2e. In addition, existing sources that emit or have the potential to emit at least 100,000 tpy CO2e and 

that undertake a modification that increases net emissions of GHGs by at least 75,000 tpy CO2e also became subject 

to PSD requirements. We refer to this Step 2 threshold as the 100,000/75,000 threshold. 4

 75 FR 31516 (June 3, 2010). 
3

that also exceed the significance level for GHG; modifications previously considered minor that 

become major modifications due to GHG emissions occurring at existing major sources; and 

modifications at newly major GHG sources due solely to emissions exceeding the significance 

threshold for GHGs. For new construction, two types of sources are listed – those that are major 

sources due solely to the emissions of GHG, and those which are classified as major due to 

conventional pollutant emissions, but also exceed the GHG significance threshold (or ‘anyway’ 

sources). 

The first line items in Table 2-1 for modifications and new construction present estimates 

of GHG-related permitting actions that would occur at ‘anyway’ sources; these are labeled in the 

table as “Current Modifications – Add Additional GHG” and “Newly Constructed Major Sources 

– Add Additional GHG.” The August 2008 ICR for the New Source Review (NSR) program 

estimates that 282 PSD and 519 non-attainment NSR permits are issued annually.5

 

 

5

 Prevention of Significant Deterioration and Non-Attainment Area New Source Review (Renewal), EPA ICR 

Number 123.23, OMB Control Number 2060-0003, 2008. A copy of this document is available in the docket for the 

final Tailoring Rule. 
Table 2-1. Number of Permit Actions Exceeding GHG6 Threshold Options 

Threshold 

100,000 

tpy major; 75,000 tpy 

sig. 

threshold 

90,000 

tpy major; 75,000 tpy 

sig. 

threshold 

80,000 tpy 

major; 

75,000 tpy 

sig. 

threshold 

75,000 tpy 

major; 

75,000 tpy 

sig. 

 threshold 

70,000 tpy 

 major; 

 70,000 tpy 

sig. 

 threshold 

6

 6

 t

Current Modifications - Add Additional GHG 448 448 448 448 448 Minor Modifications Becoming Newly Major 895 895 895 895 1,074 Modifications at Newly Major Sources 22 30 40 45 48 Modifications Total 1,365 1,373 1,383 1,388 1,570 Newly Constructed Major Sources - Add Additional GHG 240 240 240 240 240 Newly Constructed Major Sources 2 2 3 3 3 Newly Constructed Sources Total 242 242 243 243 243 Total 1,607 1,615 1,626 1,631 1,813 

6 GHG threshold options are all based on tpy CO2e. 
5

Some of the facilities applying for nonattainment permits may also undergo PSD actions at the 

same time, depending on the level of emissions for the attainment pollutants. Although there is 

no way of accurately predicting which of the 519 nonattainment actions might also coincide with 

a PSD action related to GHG emissions, we believe it is likely that most will since they typically 

involve large emission sources; thus, it is assumed all nonattainment actions from the ICR annual 

estimate will also need a PSD permit as a result of their GHG emissions. Therefore, in this 

analysis, to more accurately depict the number of PSD permitting actions occurring annually, it 

is assumed that all 801 permitting actions above involve a PSD action. We estimate that 70% of 

these permit actions are modifications, or 560 of the 801 listed.7

 Further, 80% of these 

modifications are expected to involve combustion activities with GHG emissions exceeding the 

statutory thresholds and any of the significance thresholds we considered, up to and including the 

100,000 tpy CO2e threshold, thus requiring the inclusion of GHG related requirements in a PSD 

permit.8 This equates to 448 modifications annually. We believe that any of the modifications 

that would be subject to PSD due to the conventional emissions would also be large enough to 

increase GHGs by at least 75,000 tpy of CO2e. 

The 240 remaining annual permit actions, labeled in Table 2-1 as “Newly Constructed 

Major Source- Add Additional GHG”, are assumed to be construction of new major sources as 

determined by emissions of one or more NAAQS pollutants. Due to the size and emissions of 

sources currently subject to the PSD permitting program, it is believed all of these newly 

 

7

 Based on feedback received from the National Association of Clean Air Agencies (which estimated that some 65% 

of these permitting actions involve modifications); other commenters on the proposed tailoring rule (who generally 

said that most permitting actions involve modifications); and EPA program staff experience. See “NACAA 

Summary on Permitting GHGs Under the Clean Air Act”; Memorandum from Mary Stewart Douglas, National 

Association of Clean Air Agencies to Juan Santiago, EPA/OAQPS, September 3, 2009. 

8

 The 80% estimate was obtained by reviewing a sample of PSD modification permits to determine the number 

involving combustion that would emit GHGs. This review showed that approximately 80% of PSD permitting 

actions involve combustion units of all types. These permitting actions are being permitted for, or taking limits for, 

NOx or some other combustion-related emission. These run the gamut of industrial activity, from power generators 

to manufacturing facilities, and many other types. 
6

constructed major sources will exceed each of the GHG thresholds we considered, including the 

100,000 tpy CO2e, and will also need to include GHG-related requirements in the PSD permit. In 

total, we estimate that all 688 major permitting actions mentioned above will need to factor in 

GHG requirements as indicated in Table 2-1. For permitting authorities, 50 additional burden 

hours are estimated to include the GHG requirements in a permit.9 For affected sources, 

approximately 222 additional burden hours are needed, based on the two line items in the current 

NSR ICR we expect to be impacted by the addition of GHG – approximately 120 hours to 

“obtain guidance on data needs” and 102 hours for the “preparation of BACT analysis.” That is, 

the current NSR ICR indicates that on average, affected sources spend 222 hours for these two 

activities for their conventional pollutants. We expect that they will need to spend an equal 

amount of time for these two activities for their GHG emissions. The sources will need to 

“obtain guidance on data needs” because they will be analyzing their emissions from GHG units 

and will need to prepare a separate BACT analysis for their GHG emissions, or else expand the 

BACT analysis they would otherwise do for their conventional pollutants to account for their 

GHG emissions. We believe that the remaining activities that the affected sources must 

undertake would not be appreciably lengthened by their need to include GHG emissions. 

According to the NSR ICR, approximately 74,591 minor permitting actions occur 

annually, including the following: 30% involve new minor sources, new synthetic minor sources, 

and synthetic-based modifications; 30% involve true minor modifications; 20% involve netting-

 

9

 A well-known gas with a familiar BACT process, such as NOx, requires an average of 20-30 burden hours to be 

included in a permit. As less is known regarding GHGs and the BACT decision process, expert staff judgment set 

the burden for permitting authorities to add GHG to permits at 50 hours. This is because determining BACT entails 

review and analysis of the available control techniques. For a well-known pollutant, the experience of the 

permitting authority allows it to efficiently consider the various options and narrow them down promptly to the one 

that should be considered BACT. Because no BACT determinations have ever been made, permitting authorities 

will need to invest additional time into reviewing the available technologies and selecting which one should be 

considered the best for the particular source. In the absence of any previous experience selecting BACT for GHG 

sources, we estimate that twice as much time will be necessary as for conventional pollutants. 
7

based minor modifications; and 20% involve minor/administrative permit revisions.10 We 

believe that a number of projects that could have taken limits or netted out of PSD review and 

thereby obtain a minor permit will now be required to apply for a major PSD permit, depending 

on the significance threshold set for GHGs. These projects are identified in Table 2-1 under 

“Minor Modifications Becoming Newly Major.” Combining the number of synthetic-based 

modifications (7,459) and netting-based modifications (14,909) identified in the ICR, 

approximately 22,368 of these actions could potentially become major modifications subject to 

PSD review if their associated GHG emissions increases exceed the selected GHG significance 

threshold option. We did not count ‘new minor sources’ and ‘new synthetic minors’ because we 

have already accounted for them as potential major GHG sources if their PTE emissions exceed 

the selected GHG major source threshold option. 

Based on staff review of samples of minor source permits, it is estimated that 80% of the 

current minor modification actions likely involve combustion sources – totaling 17,894 actions 

of the total 22,368 minor modification actions.11 Some of these actions may trigger the 

requirements of the PSD program depending on their GHG emission increases and the selected 

GHG significance threshold. In the absence of extensive experience involving GHG sources, we 

determined the number of these actions on the following basis: We assumed the following 

percentage of the total 17,984 actions would move to a major modification status due to GHG 

increases for each of the GHG significance threshold options considered in this analysis: 10% at 

50,000 tpy CO2e; 8% at 60,000 tpy CO2e; 6% at 70,000 tpy CO2e; and 5% at 75,000 tpy CO2e. 

To determine these percentages, we considered the relative emissions of CO2 emissions to NOx 

emissions at the current major modification significance level for NOx (40 tpy). For example, for 

an average natural gas combustion boiler (a common industrial combustion unit that is part of 

 

10 See NSR ICR at page 11. 11 See footnote 6, above (basis for 80% calculation). 
8

many modification projects), a 40 tpy NOx emissions would coincide with a 56,000 tpy CO2e 

level. Since many combustion related projects keep just under the 40 tpy NOx level to avoid 

major modification status, we assume that the CO2e emissions for a similar project will be 

around the 50,000 tpy CO2e level. Based on the relationship in combustion-related emission 

levels between NOx and CO2e just described, we believe it is reasonable to assume that a 

decreasing proportion of projects will be significantly large enough, or they may emit GHGs 

close enough to the GHG significance level, to be able to limit their operations or net-out for 

GHGs like they can for NOx. In the absence of experience and quantitative information from 

commenters on the Tailoring Rule, we made the following assumptions regarding how many of 

these formerly minor modification projects would be subject to major PSD review at the 

different GHG significance threshold options: at the 50,000 tpy CO2e significance threshold, we 

estimate that 10% of these previously minor now major modifications will be covered by PSD; 

at 60,000 tpy CO2e and 70,000 tpy CO2e we estimate 8% and 6% respectively; and lastly, at the 

75,000 tpy CO2e significance level we estimate that only 5% of these currently minor 

modification projects move into a major modification status for GHGs 

In addition to sources becoming subject to PSD requirements because of GHG emissions 

related to modifications, new construction will occur that will require a PSD permit solely due to 

the source’s potential GHG emissions, identified in Table 2-1 as “Newly Constructed Major 

Sources.” Based on the source data obtained from the GHG thresholds evaluation, these newly 

constructed major sources involve both industrial and commercial/residential facilities.

12 The 

current NSR ICR notes that permitting authorities spend approximately 300 hours processing and 

issuing a new construction industrial source PSD permit. Sources spend almost 870 hours on 

average preparing for the same permit. The EPA estimates the commercial/residential permits to 

 

12 “Technical Support Document: Additional Threshold Analysis Greenhouse Gas Tailoring Rule,” October 12, 

2011. 
9

take 70% of the time required to complete an industrial permit, resulting in approximately 210 

hours and 866 hours for permitting authorities and sources respectively.13 There are also many 

permit preparation activities that represent a fixed cost, such as preparation of notices and public 

hearings. Of the sources falling in this category, the number requiring PSD permitting will vary 

depending on where the thresholds for triggering PSD review (both major source and 

modifications thresholds) are established. 

Table 2-2. Average Permitting Authority Burden per GHG PSD Permit 

Type 

Activity 

Burden 

Hours per 

Permit - 

Industrial 

Burden Hours 

per Permit - 

Commercial/ 

Residentiala

 Attend Preapplication Meetings 36 27

 Answer Respondent Questions 20 15

 Log In and Review Data Submissions 16 12

 Request Additional Information 8 6

 Analyze for and Provide Confidentiality Protection 24 2

 Prepare Completed Applications for Processing 38 29

 File and Transmit Copies 8 6

 Prepare Preliminary Determination 36 27

 Prepare Notices for and Attend Public Hearings 40 30

 Application Approval 48 36

 Notification of Applicant of PA Determination 8 6

 Submittal of Information on BACT/LAER to RBLC 19 14

Total Burden Hours per Permit 301 210

a In general, to process commercial/residential permits, permitting authorities will have to spend 75% of the amount of 

time they spend on industrial permits, except they will have to spend even less time on confidentiality due to the fact that 

most residential sources are not likely to be concerned about confidentiality. Commercial/residential permits will be 

much simpler than industrial permits, but a large part of the permitting costs are fixed costs. For example, organizing and 

holding a hearing for a much simpler permit, compared to a more complex permit, nevertheless take almost as long 

because of the document preparation, travel, and organizational details. 

 

13 See Tables 2-2 and 2-3. 
10

Table 2-3. Average Source Burden per GHG PSD Permit Type 

Activity 

Burden Hours 

per Permit - 

Industrial 

Burden Hours per 

Permit - 

Commercial/ 

Residentiala

Preparation and Planning 

 Determination of Compliance Requirements 170 170

 Obtain Guidance on Data Needs 120 120

 Preparation of BACT Analysis 102 102

Data Collection and Analysis 

 Air Quality Modeling 200 40

 

Determination of Impact on Air Quality 

Related Values 100 30

 Post-construction Air Quality Monitoring 50 20

Permit Application 

 

Preparation and Submittal of Permit 

Application 60 60

 Public Hearings 24 24

 Revisions to Permit 40 40

Total Burden 866 606

a

PSD permit applications for commercial/residential sources will be significantly simpler than industrial source PSD 

permit applications. However, due to their inexperience, we estimate commercial/residential sources will take as long to 

complete their steps for their permit application as it will for industrial sources to complete their steps. 

Commercial/residential sources will, on average, have much less work for data collection and analysis. We estimate that 

they will have approximately 25% as much work in these areas (90 hours) compared to industrial sources (350 hours). 

However, commercial/residential sources will have to spend some time on data collection analysis is because some of 

them will have conventional pollutants that they emit in amounts that exceed the “significance” levels, but not the 

“major” levels, and they will have to analyze those conventional pollutants. Our 25% estimate is based, in the absence of 

actual experience or quantitative data from commenters, on our judgment that significantly less than 50% of 

commercial/residential sources emit conventional pollutants in amounts that equal or exceed the significance levels, but 

those that do may have to spend more time than industrial sources on data collection because they are unfamiliar with the 

tasks and therefore will face a learning curve. 

Finally, an existing, but newly classified major source for GHG, may undergo a 

modification for which it will then be subject to PSD permitting requirements. This category of 

PSD permitting activity is listed on Table 2-1 as “Modifications at Newly Major Sources.” With 

this new major source status, these facilities must apply for and be issued a PSD permit, if they 

undergo a major modification. See Appendix A for a list of newly major sources at different 

major source GHG thresholds. We estimate that 4% of these newly major sources will undergo 

modifications. This rate was obtained by dividing the current 560 annual PSD modification-
11

related permit actions (i.e., 70% of 801 actions identified in the NSR ICR) by the existing major 

source population of 14,700 major source title V permits. This represents our best available 

estimate of the rate of PSD modification activity at major sources, and we make the assumption 

that this rate will also apply for newly major GHG sources. We recognize that there is some level 

of uncertainty in applying this rate to GHG-only sources, particularly for sources in 

unconventional sectors such as commercial and residential categories, however we believe at 

higher GHG thresholds, where large industrial sources predominate, that this modification rate 

provides a reasonable estimate of modification activity. As no data are yet available for 

commercial/residential sources and because we cannot conclude that they will differ from 

industrial sources, we select the same 4% rate for modification activity. 

Title V Permits

Title V programs also complete several types of permitting actions annually, 

including processing and issuing new permits, permit revisions, and permit renewals. 

Newly constructed major sources or sources designated newly major due to a 

modification are required to apply for and be issued a title V permit in order to operate. In 

addition to sources new to title V, permitting authorities must add GHG terms to permits 

for sources exceeding the threshold set for GHG emissions. Permitting authorities may 

face burdens to update existing title V permits for GHG under two possible scenarios: (1) 

EPA promulgates or approves any applicable requirements for GHGs that would apply to 

such a source, which would generally require a permit reopening or renewal application, 

or (2) the source makes a change that would result in an applicable requirement for GHG 

to newly apply to the source, such as PSD review, which would generally require an 

application for a permit revision. Permitting authorities will also need to process permit 
12

renewal applications, generally on a five-year cycle, and such renewals would need to 

assure that the permit properly addresses GHG. 

The April 2007 title V ICR estimates that 50 permits are completed every year for new 

sources.14 For this analysis, it is assumed that all 50 of these typically large industrial-type 

sources will be capable of potentially emitting GHG and will need to add GHG-related 

requirements to the permit. The estimated burden per title V permit in the ICR represents an 

average of multiple pollutants; we estimate the addition of GHGs will add an additional 10% of 

the time currently estimated for a new title V permit. We believe that 10% is the appropriate 

amount because for the most part, these sources will simply need to add information concerning 

inventory, reporting, or monitoring of their GHG emissions, as appropriate, which they can 

readily do. 

The ICR also identifies 3,267 permit renewals conducted on an annual basis. As not all 

sources potentially emit GHG above a determined threshold, this analysis examines the 

estimated 80% involving combustion activities that most likely have the potential to emit GHG 

above the series of potential thresholds evaluated.15 Therefore, approximately 2,614 sources will 

need to address GHG in the permit renewal. 

Revisions to title V permits will also be necessary based on the number of modifications 

calculated for this analysis. Revisions occurring specifically due to GHG may involve significant 

revisions, minor revisions, or administrative actions to operating permits. EPA estimates that this 

activity will require 40 hours per permit on average for permitting authorities to complete.16 The 

 

14 Information Collection Request for State Operating Permit Regulations (Renewal), EPA ICR Number 1587.07, 

OMB Control Number 2060-0243, 2007. A copy of this document is available in the docket for the final Tailoring 

Rule. 

15 The 80% estimate was obtained through a review of existing title V permit source categorization. 16 The Title V ICR indicates the burdens associated with revisions are as follows: 90 hours for a significant revision, 

30 hours for a minor revision, and 5 hours for an administrative action. See Table 8 at 23. It is not known which 

revision will be required for any modification that exceeds the GHG significance level threshold; therefore, the EPA 

averages the three permitting burdens to obtain a value of 40 hours per permit. 
13

number of operating permit revisions will vary based on the number of previously minor 

modifications now qualifying as major modifications, and modifications at newly major sources, 

both listed in Table 2-1. At any level, it is assumed that the 448 modifications involving 

combustion that occur annually will need to include any GHG requirements in the revision of 

their respective title V permits. EPA estimates that permitting authorities will spend, in addition 

to the current burden to issue a title V permit revision, an additional 10% of the 40 hours needed 

to complete this process, or four hours per action. 

Finally, new industrial and commercial/residential sources will be entering title V 

permitting programs annually due solely to their GHG emissions. These commercial/residential 

sources that exceed the major source threshold solely due to their GHG emissions will not likely 

have substantial applicable requirements in the near term and/or will not require as much time to 

process as those for industrial sources, which have other applicable requirements in addition to 

those related to their GHG emissions. However, the EPA believes both permitting authorities and 

commercial/residential sources will confront challenges as they have little experience permitting 

GHGs for these types of facilities. This will increase the time needed to assess GHG emissions, 

complete the application, and respond to permitting authority comments. We also expect that in 

many cases the draft permits will undergo high levels of public participation through public 

comment periods, public hearings, and petitions for reconsideration. Therefore, EPA assumes 

preparing a permit for affected commercial/residential sources will take 50% of the time a 

permitting authority currently spends on issuing a title V permit for an industrial source. 
14

Table 2-4. Average Permitting Authority Burden per GHG Title V Permit 

Activity 

Burden 

Hours per 

Permit – 

Industrial 

Burden Hours 

per Permit - 

Commercial/ 

Residentiala

Permit Application Review 100 33 

Draft Permits Preparation 150 50 

Comment Period Notification 10 10 

Hold Public Hearings 100 90 

Interaction with EPA 20 5 

Analyze Public Comments 40 20 

Permits Issuance 8 6 

Total Burden 428 214 

a

Commercial/residential permits will be simpler, so that it would take the permitting authority about 1/3 of the 

time to review the permit application and draft the permit than it would for an industrial source permit. The 

comment period notification and time for public hearings, however, would be about the same because of the 

fixed time burdens necessary to provide notice and hold hearings. The amount of time interacting with EPA 

would be much less because of the relative simplicity of the permits. Analyzing public comments would take 

half as long as for an industrial permit because although the permits are much simpler, there could be a fair 

amount of public interest because of the location of the source. Permit issuance would take a less time than for 

an industrial source because most of the costs are fixed, although the permit is simpler. 

Table 2-5. Average Source Burden per GHG Title V Permit 

Activity 

Burden 

Hours per 

Permit – 

Industrial 

Burden Hours 

per Permit - 

Commercial/ 

Residentiala

Prepare Application 300 150 

Draft Permits Interaction 40 20 

Public Hearing Participation 10 10 

Total Burden 350 180 

a

Commercial/residential permit applications will be significantly simpler than industrial source title V permit 

applications. However, due to their inexperience, we estimate commercial/residential sources will take half as 

long to complete their steps for their permit application as it will for industrial sources to complete their steps. 

Less interaction, again 50% less time, will be needed with permitting authorities during the permit drafting 

process. However, public hearing participation will likely require the same amount of time because of the fixed 

time burdens necessary to complete hearings. 

Uncertainties in Estimates of Affected Sources 

To date, EPA has observed lower permitting levels than expected and does not yet have 

enough data to evaluate the accuracy of our estimates. However, we expect the pace of 
15

permitting to increase. For the purposes of moving forward, we continue to estimate burden 

using the same methodology applied in the Tailoring Rule analysis. Uncertainties in the 

estimates were noted in the TSD; we reiterate those uncertainties below. 

In order to estimate the number of facilities that exceed a given GHG threshold (such as 

the Step 2 thresholds of 100,000/75,000 tpy CO2e for baseline analysis), it is necessary to have 

emissions inventory data at the facility or building level, including, and particularly for lower 

threshold scenarios, numerous small sources in the residential and commercial sectors (e.g., 

apartment buildings and office buildings). Historically, however, EPA has not collected sectorwide, facility-level information for GHG emissions under the CAA (with the exception of 

information from electric generating units required to report CO2 emissions under the Acid Rain 

Program reporting requirements). To date, national EPA inventories of GHG sources have 

primarily focused on ‘top-down’ estimates of GHG emissions from sectors and sources, and not 

facility-level estimates. As a result, many of the uncertainties described here result from the 

absence of a comprehensive data set of facility-level GHG emissions across all sectors. A full 

description of the methodology used for determining facility level emissions is provided in our 

GHG thresholds evaluation study, which can be found at EPA-HQ-OAR-2009-0517.17 

For residential, commercial, and smaller manufacturing operations, our current analysis 

relies on sample facility datasets and ‘top-down’ sector data (e.g., national fuel consumption 

statistics and/or building characteristics). There are inherent uncertainties in developing source 

counts from the allocation of these nationally aggregated statistics. The allocation factors we 

used, based on U.S. Energy Information Administration statistical sampling procedures and 

energy consumption statistics, are likely the best available to estimate the population of 

 

17 “Technical Support Document: Additional Threshold Analysis Greenhouse Gas Tailoring Rule,” October 12, 

2011. 
16

residential, commercial, and small manufacturing sources exceeding different GHG thresholds. 

However, uncertainties may result in either overestimating or underestimating GHG emissions 

for a given individual facility. It is worth noting that our estimates for the largest GHG emitting 

sources, such as electric utilities and refineries, are derived from bottom-up calculations of 

individual facility/building emissions so that there is increased certainty in evaluating and 

comparing the facility counts at the higher GHG threshold scenarios where residential and 

commercial sources are not highly affected. Although there are different levels of uncertainty in 

our facility level estimates across sectors, we do believe that the data are sufficiently robust to 

use in the aggregate to assess national permitting level impacts. 

EPA’s estimate of affected sources is based on their potential to emit (PTE) emissions, as 

opposed to actual emission levels. PTE is defined as the maximum capacity of a stationary 

source to emit a pollutant under its physical and operational design, including certain legal 

limitations, for example, on emissions or hours of operation. NSR and title V programs both use 

PTE for defining and identifying major sources. Although we have attempted to identify 

reasonable adjustments to account for PTE in our methodology, there are significant 

uncertainties in our PTE-based estimates, particularly for the commercial, residential and small 

manufacturing sectors that have not traditionally been subject to any form of air permitting. In 

practice, for example, for the residential sector and for many of the facilities in the commercial 

sector, where CO2 emissions are primarily due to space heating/appliance usage, the combustion 

units are not likely to be used constantly at their maximum rated capacity because heating is not 

needed year-round and heating systems have thermostats. However, for our analysis we do 

assume full PTE-based estimates for the residential and commercial sectors, using PTE 
17

adjustment factors of 10 and 6.6, respectively to adjust actual emissions to PTE level.18 Absent 

industry specific data, for small manufacturing source categories we assume a PTE adjustment 

factor of 2; individual manufacturing facilities may operate their combustion equipment at levels 

above and below this capacity utilization rate, but we believe this PTE adjustment reflects a 

reasonable average rate across the variety of small manufacturing facilities included in the 

threshold analysis. Ultimately, the number of sources brought into either the NSR or title V 

programs due solely to their PTE would depend on how EPA interprets PTE for various types of 

emitting equipment (e.g., space-heating furnaces in residential and commercial buildings), and 

the extent to which streamlined mechanisms are made available for sources to obtain legal limits 

on their PTE so that the programs are not applicable. No such decisions or interpretations have 

been made at this point and, as mentioned in the preamble, they will require significant time to 

develop. As a result, our threshold analysis uniformly assumes that no PTE limits are in place 

for any of the affected sectors, which may likely be the case in the immediate stages of GHG 

permitting for affected sources. 

There is significant uncertainty in both our modification rate for newly major GHG 

sources and in our estimate of modification activity at existing major sources that will become 

subject to PSD review for GHG emission increases. The general uncertainty results from 

predicting not only how many major sources will undergo physical or operational changes in any 

given year, but also which of those changes would result in GHG emissions increases that would 

exceed a proposed GHG significance level. First, information is not available across sectors and 

source categories on the types and numbers of specific physical and operational changes that 

would result in GHG emissions increases in amounts that can be estimated and that therefore can 

 

18 For more detail on the PTE adjustment, refer to pages 62-69 of the “Technical Support Document for Greenhouse 

Gas Emissions Thresholds Evaluation, March 29, 2010 (EPA-HQ-OAR-2009-0517-19158).

 
18

be compared to various GHG emissions significance thresholds. Second, there is uncertainty in 

how many project modifications will occur within any given year because decisions on these 

projects are driven by facility- and sector-based growth patterns and business planning decisions. 

Lastly, some source categories and units that emit GHGs have not previously been subject to any 

type of permitting or reporting requirements; as a result, for these sources, there is very little 

historical record for use in estimating the number and types of projects that would occur at these 

sources and, in turn, establish an appropriate significance threshold for GHGs. 

Uncertainties in Permitting Costs

The primary reference sources for our estimate of burden hours and costs for permitting 

GHGs are the current ICRs for the PSD and title V programs. There are a number of 

uncertainties introduced in using these references for costing GHG permitting activities. First, 

we are assuming that the average, conventional pollutant per-permit costs will be similar for 

GHGs. We do recognize the likelihood that residential and commercial permits would be simpler 

and have a lower per-permit burden than traditional industrial sources, and have made 

adjustments for this. However, for industrial sources we assume per-permit costs on par with 

what are estimated in the latest ICRs for PSD and title V programs. There is uncertainty in 

applying these average ICR-based costs to GHG permitting, even for industrial sources, because 

there is no historical track record for permitting these GHG sources and thus any cost 

efficiencies that have been realized over the years for conventional pollutant permitting, and thus 

reflected in the current ICRs, may not be initially realized for GHG permitting. For example, we 

assume the same public hearing estimate as included in the ICR for current PSD permits (i.e., 

that 1 in 50 major PSD permits require a hearing) for GHG sources, this number may be higher 

initially if there ends up being significantly more public interest in these permits. We do believe 
19

overall, however, that larger facilities, especially those affected at higher threshold levels, will 

have had sufficient permitting experience such that out ICR-based costs should reasonably 

reflect the added burden of including GHGs. 

As mentioned above, in our burden scenario analyses we do discount the ICR-based perpermit costs for residential and commercial sources to reflect what we believe will generally be 

simpler permits, involving primarily uniform combustion type equipment. For PSD we discount 

the per-permit cost by 30%, and for title V we discount the per-permit cost by 50%. There is 

significant uncertainty in these estimated discounts since we have no track record for permitting 

these smaller commercial and residential sources. However, we do believe that, based solely on 

the type and uniformity of the GHG emission units that would be subject to permitting at these 

facilities under lower GHG threshold scenarios, that average per-permit costs would be less than 

those currently experienced by more complex industrial facilities, with numerous emission units, 

for currently regulated pollutants. 

3. Evaluation of ICR-based Resource Requirements for Permitting Authorities at Different 

 Possible GHG Permitting Thresholds 

 For this proposal, EPA examined resource requirements at the current Step 2 thresholds 

as well as 50,000 tpy CO2e and five thresholds in between. These thresholds range from the 

current 100,000 tpy CO2e major source applicability threshold for PSD and title V down to a 

50,000 tpy CO2e threshold, with associated PSD GHG significant thresholds ranging from the 

current 75,000 tpy CO2e through 50,000 tpy CO2e, as the choice of a PSD significance threshold 

also has a direct impact on title V burdens since a greater number of PSD permit requirements 

that result from modification activities will result in a greater number of necessary title V 

revisions. 
20

PSD Permits

Table 3-1 presents the estimated burden for permitting authorities at different possible 

PSD GHG major source applicability thresholds. Descriptions of the different thresholds selected 

are provided below. Burden estimates for the PSD program are calculated based on listed values 

obtained from Tables 6-1 and 6-2 the NSR ICR.19 The ICR does not distinguish between new 

construction and modification actions; therefore, Table 3-1 combines the actions into permit 

preparation issuance based solely on GHG emissions or the addition of GHG requirements to 

permits being issued for conventional sources, or ‘anyway’ permits. PSD permit preparation and 

issuance is further divided into industrial and commercial/residential sources since less time is 

required for commercial/residential sources. 

 

19 All threshold levels represented estimate burden over current ICR values. At this time, a new program ICR is 

under development for the NSR program that will incorporate necessary adjustments from implementation of the 

Tailoring Rule. 
21

Table 3-1. Additional Permitting Authority PSD Burden with GHG (Annual) 

Activity 

Burden 

Hours 

per 

Permit 

Affected 

Permits 

Total 

Burden 

(hours) 

Total Cost 

($2007)a

Baseline: 100,000 tpy; 75,000 tpy Significance Threshold 

 PSD Permit Preparation and Issuance - Industrial 301 915 275,415 $21,267,546

 

PSD Permit Preparation and Issuance - 

Commercial/Residential 210 4 840 $64,865

 Additions to Current PSD Applications 50 688 34,400 $2,656,368

 Total Additional Burden 310,655 $23,988,779

90,000 tpy; 75,000 tpy Significance Threshold 

 PSD Permit Preparation and Issuance - Industrial 301 922 277,522 $21,430,249

 

PSD Permit Preparation and Issuance - 

Commercial/Residential 210 5 1,050 $81,081

 Additions to Current PSD Applications 50 688 34,400 $2,656,368

 Total Additional Burden 312,972 $24,167,698

80,000 tpy; 75,000 tpy Significance Threshold 

 PSD Permit Preparation and Issuance - Industrial 301 927 279,027 $21,546,465

 

PSD Permit Preparation and Issuance - 

Commercial/Residential 210 11 2,310 $178,378

 Additions to Current PSD Applications 50 688 34,400 $2,656,368

 Total Additional Burden 315,737 $24,381,211

75,000 tpy; 75,000 tpy Significance Threshold 

 PSD Permit Preparation and Issuance - Industrial 301 931 280,231 $21,639,438

 

PSD Permit Preparation and Issuance - 

Commercial/Residential 210 12 2,520 $194,594

 Additions to Current PSD Applications 50 688 34,400 $2,656,368

 Total Additional Burden 317,151 $24,490,400

70,000 tpy; 70,000 tpy Significance Threshold 

 PSD Permit Preparation and Issuance - Industrial 301 1,113 335,013 $25,869,704

 

PSD Permit Preparation and Issuance - 

Commercial/Residential 210 12 2,520 $194,594

 Additions to Current PSD Applications 50 688 34,400 $2,656,368

 Total Additional Burden 371,933 $28,720,666

60,000 tpy; 60,000 tpy Significance Threshold 

 PSD Permit Preparation and Issuance - Industrial 301 1,478 444,878 $34,353,479

 

PSD Permit Preparation and Issuance - 

Commercial/Residential 210 17 3,570 $275,675

 Additions to Current PSD Applications 50 688 34,400 $2,656,368

 Total Additional Burden 482,848 $37,285,523

50,000 tpy; 50,000 tpy Significance Threshold 

 PSD Permit Preparation and Issuance - Industrial 301 1,906 573,706 $44,301,577

 

PSD Permit Preparation and Issuance - 

Commercial/Residential 210 28 5,880 $454,054

 Additions to Current PSD Applications 50 688 34,400 $2,656,368

 Total Additional Burden 613,986 $47,411,999

a

Labor cost of $77.22/hr from Prevention of Significant Deterioration and Non-Attainment Area New Source Review (Renewal), EPA ICR 

Number 1230.23, OMB Control Number 2060-0003, 2008. 

b

Assume permit preparation and issuance for commercial/residential permits takes 70% the amount of time needed to prepare and issue an 

industrial permit. 

c

For current permit applications, assume it takes an additional 50 hours to include GHG requirements in the permit. 
22

Current Threshold Estimates

Step 1 involved only sources required to get a PSD permit due to their non-GHG 

emissions and then were further required to add GHG related requirements as a result of GHG 

emissions increases from modifications, or GHG emissions at newly constructed facilities, 

exceeding a significance threshold of 75,000 tpy GHG. In this scenario, only the annual 688 PSD 

permit actions derived from the NSR ICR were expected to need the inclusion of GHG related 

requirements to the permits. The additional burden to permitting authorities under this scenario 

was estimated at 34,000 hours at a cost of $2.7 million. 

Step 2 of the Tailoring Rule, which began on July 1, 2011, continues Step 1 and applies 

PSD and title V to new sources as well as existing sources that are not ‘anyway’ sources and that 

emit, or have the potential to emit, at least 100,000 tpy CO2e. In addition, existing sources that 

emit or have the potential to emit at least 100,000 tpy CO2e and that undertake a modification 

that increases net emissions of GHGs by at least 75,000 tpy CO2e also become subject to PSD 

requirements. 

At this current threshold, the earlier TSD estimated that permitting authorities would 

experience an increase up to 919 new permit actions annually due to the inclusion of GHGs. The 

corresponding burden was expected to require up to an additional 311,000 hours at a cost of $24 

million. 

Alternate Threshold Scenarios

Additional annual burden was determined at five different major stationary source 

thresholds in order to evaluate the relative differences in impacts to permitting authorities. 

Estimates represent the additional burden and costs due to GHG permitting at lower thresholds, 
23

beyond to the burden currently experienced and estimated in the ICR by permitting authorities 

and sources. 

The first scenario is the 90,000 tpy CO2e threshold with 75,000 tpy CO2e significance 

threshold. Results of this analysis indicate a potential of 927 new permits, plus 688 permit 

actions to include GHG related requirements into current PSD permitting actions (including both 

new construction and modifications). This potential additional workload equates to 313,000 

hours for permitting authorities at a cost of $24.2 million. 

Decreasing the emission threshold to 80,000 tpy CO2e, while maintaining the 75,000 tpy 

CO2e significance threshold, would lead to an estimated 316,000 hours additional burden at a 

cost of $24.4 million. This scenario estimates 938 potential new construction or modification 

activities subject to PSD permitting annually due to GHG. 

Setting a threshold of 75,000 tpy CO2e with a significance threshold of 75,000 tpy CO2e, 

permitting authorities would spend an estimated 317,000 hours preparing and issuing permits, at 

a cost of $24.5 million. At this threshold, EPA estimates 1,813 potential new actions require PSD 

permits. 

Next, at the 70,000 tpy CO2e threshold with a 70,000 tpy CO2e significance threshold, the 

annual permitting authority burden would increase by 372,000 hours at an estimated cost of 

$28.7 million. In this scenario, 1,125 potential new permit actions will occur annually. 

At a 60,000 tpy CO2e threshold, with a 60,000 tpy CO2e significance threshold for 

modifications, EPA estimates a potential of 1,478 new industrial PSD permit actions and 17 

commercial/residential. Permitting authorities would spend an estimated 483,000 additional 

hours on permits at a cost of $37.3 million. 

Finally, as identified in the Tailoring Rule analysis, lowering the emission threshold to 

50,000 tpy CO2e would lead to an estimated 614,000 hours additional burden at an approximate 
24

cost of $474 million. This scenario estimates 1,934 potential new construction or modification 

activities subject to PSD permitting annually due to GHG. 

Title V Permits

Table 3-2 presents the estimated burden for permitting authorities at different possible 

title V GHG major source applicability thresholds. Descriptions of the different thresholds 

selected are provided below. Burden estimates are calculated and annual values derived from 

Tables 7 and 8 of the current Title V ICR.20 

Current Threshold Estimates 

Step 1, which began on January 2, 2011, involved only sources required to get a title V 

permit for emissions other than GHG and that are required to add GHG related requirements. 

Under this Step, only the annual issuance of 50 permits noted in the title V ICR were expected to 

need the inclusion of GHG related requirements to the permits. The additional burden to 

permitting authorities was estimated at 27 million hours at a cost of $1.3 million. 

Building on Step 1, Step 2 began on July 1, 2011. Utilizing a 75,000 tpy CO2e PSD 

significance threshold, the earlier version of this TSD estimated the annual permitting authority 

burden to increase by 161,000 hours at a cost of $7.4 million. At this significance threshold, 

approximately 915 operating permit revisions could be necessary due to GHG. 

 

20 For consistency, the permitting authority labor costs are updated to 2007 dollars utilizing the 2007 General 

Schedule Salary Table from the Office of Personnel Management. 
25

Table 3-2. Additional Permitting Authority Title V Burden with GHG (Annual) 

Activity 

Burden 

Hour 

per 

Permit 

Affected 

Permits 

Total 

Burden 

(hours) 

Total Cost 

($2007)a

100,000 tpy (associated with PSD 100,000 tpy maj./75,000 tpy sig.) 

 New Permit Preparation and Issuance - Industrial 428 172 73,473 3,379,773

 Add GHG component to new Non-GHG Permitb 43 50 2,150 $98,900

 New Permit Preparation and Issuance - Commercial/Residentialc 214 18 3,781 $173,911

 Permit Revisions - due to GHG 40 915 36,600 $1,683,600

 Permit Revisions - add GHG to Current Non-GHG Permits 4 448 1,792 $82,432

 Permit Renewalsd 9 2,614 23,526 $1,082,196

 Total Additional Burden 141,322 $6,500,812

90,000 tpy (associated with PSD 90,000 tpy maj./75,000 tpy sig.) 

 New Permit Preparation and Issuance - Industrial 428 229 97,869 $4,501,989

 Add GHG component to new Non-GHG Permit 43 50 2,150 $98,900

 New Permit Preparation and Issuance - Commercial/Residential 214 25 5,421 $249,381

 Permit Revisions - due to GHG 40 895 35,800 $1,646,800

 Permit Revisions - add GHG to Current Non-GHG Permits 4 448 1,792 $82,432

 Permit Renewals 9 2,614 23,526 $1,082,196

 Total Additional Burden 166,559 $7,661,699

80,000 tpy (associated with PSD 80,000 tpy maj./75,000 tpy sig.) 

 New Permit Preparation and Issuance - Industrial 428 277 118,556 $5,453,576

 Add GHG component to new Non-GHG Permit 43 50 2,150 $98,900

 New Permit Preparation and Issuance - Commercial/Residential 214 68 14,552 $669,392

 Permit Revisions - due to GHG 40 895 35,800 $1,646,800

 Permit Revisions - add GHG to Current Non-GHG Permits 4 448 1,792 $82,432

 Permit Renewals 9 2,614 23,526 $1,082,196

 Total Additional Burden 196,376 $9,033,296

75,000 tpy (associated with PSD 75,000 tpy maj./75,000 tpy sig.) 

 New Permit Preparation and Issuance - Industrial 428 301 128,685 $5,919,525

 Add GHG component to new Non-GHG Permit 43 50 2,150 $98,900

 New Permit Preparation and Issuance - Commercial/Residential 214 76 16,264 $748,144

 Permit Revisions - due to GHG 40 895 35,800 $1,646,800

 Permit Revisions - add GHG to Current Non-GHG Permits 4 448 1,792 $82,432

 Permit Renewals 9 2,614 23,526 $1,082,196

 Total Additional Burden 208,217 $9,577,997

70,000 tpy (associated with PSD 70,000 tpy maj./70,000 tpy sig.) 

 New Permit Preparation and Issuance - Industrial 428 335 143,380 $6,595,480

 Add GHG component to new Non-GHG Permit 43 50 2,150 $98,900

 New Permit Preparation and Issuance - Commercial/Residential 214 78 16,763 $771,113

 Permit Revisions - due to GHG 40 1,074 42,960 $1,976,160

 Permit Revisions - add GHG to Current Non-GHG Permits 4 448 1,792 $82,432

 Permit Renewals 9 2,614 23,526 $1,082,196

 Total Additional Burden 230,571 $10,606,281
26

Alternate Threshold Scenarios

After reviewing the current established thresholds, additional burden was determined at

five different major stationary source thresholds in order to evaluate the relative differences in 

impacts to permitting authorities. Estimates represent the additional annual burden and costs due 

to GHG permitting beyond the burden and costs currently experienced by permitting authorities 

and sources. 

Results of the analysis at the first threshold, 90,000 tpy CO2e, indicate a potential of 254 

new permits as well as 50 permits that would need to include GHG requirements in their permits. 

This additional workload equates to 167,000 hours for permitting authorities at a cost of $7.7 

Table 3-2 (continued). Additional Permitting Authority Title V Burden with GHG (Annual) 

Activity 

Burden 

Hour 

per 

Permit 

Affected 

Permits 

Total 

Burden 

(hours) 

Total Cost 

($2007)a

60,000 tpy (associated with PSD 60,000 tpy maj./60,000 tpy sig.) 

 New Permit Preparation and Issuance - Industrial 428 517 221,133 $10,172,133

 Add GHG component to new Non-GHG Permit 43 50 2,150 $98,900

 New Permit Preparation and Issuance - Commercial/Residential 214 116 24,895 $1,145,185

 Permit Revisions - due to GHG 40 1,432 57,280 $2,634,880

 Permit Revisions - add GHG to Current Non-GHG Permits 4 448 1,792 $82,432

 Permit Renewals 9 2,614 23,526 $1,082,196

 Total Additional Burden 330,777 $15,215,727

50,000 tpy (associated with PSD 50,000 tpy maj./50,000 tpy sig.) 

 New Permit Preparation and Issuance - Industrial 428 981 419,868 $19,313,928

 Add GHG component to new Non-GHG Permit 43 50 2,150 $98,900

 New Permit Preparation and Issuance - Commercial/Residential 214 208 44,441 $2,044,271

 Permit Revisions - due to GHG 40 1,906 76,240 $3,507,040

 Permit Revisions - add GHG to Current Non-GHG Permits 4 448 1,792 $82,432

 Permit Renewals 9 2,614 23,526 $1,082,196

 Total Additional Burden 568,017 $26,128,767

a

Salaries from title V ICR adjusted to 2007 dollars using 2007 OPM General Schedule Salary Table available at: 

http://www.opm.gov/oca/07tables/index.asp 

b

Incorporating GHG information/requirements into significant revisions and permit renewals adds an additional 10% of the current time (90 hours each) 

c

New commercial/residential permits require half the time needed for new industrial permits d

The title V ICR estimates that 3,267 permits annually undergo renewal - assume 80% of these involve combustion 

___________________________________________________________________________________________________________________________ 
27

million. As with PSD programs, increases are due to more complete estimates of annual 

modifications and the revised burden associated with commercial/residential permits. 

Decreasing the emission threshold to 80,000 tpy CO2e would lead to an estimated 

196,000 hours additional burden at a cost of $9 million. This scenario estimates 345 new sources 

would be subject to title V permitting annually due to GHG. 

At the next threshold examined, 75,000 tpy CO2e, permitting authorities would 

experience an additional workload of 208,000 hours at a cost of $9.6 million. Potential new 

permits at this threshold are estimated to include 301 industrial permits and 76 

commercial/residential permits, leading to 377 sources being subject to title V annually. 

Setting a threshold of 70,000 tpy CO2e, permitting authorities wouldspend an estimated 

231,000 hours preparing and issuing permits, at a cost of $10.6 million. At this threshold, 

approximately 413 new sources would be subject to title V permitting annually. 

Lowering the threshold to 60,000 tpy CO2e, we expect permitting authorities will spend 

an estimated 331,000 additional hours on permits at a cost of $15.2 million. Over 630 new 

sources are expected to potentially enter title V permitting programs based on their GHG 

emissions. 

The final scenario at 50,000 tpy CO2e will lead to an estimated 568,000 hours additional 

burden at a cost of $26.1 million. This scenario estimates 1,189 potential new sources will be 

subject to title V permitting annually due to GHG. 
28

APPENDIX A 

Table A-1. Newly Major Affected Source Estimates Based on Threshold21 

Source Type 100,000 tpy 90,000 tpy 80,000 tpy 75,000 tpy 70,000 tpy 60,000 tpy 50,000 tpy 

EGUs 0 0 0 0 0 0 0

Industrial 256 277 292 302 313 337 1,934

Oil/Gas/Coal production 52 57 61 64 64 71 75

Waste Treatment 193 331 455 525 598 749 910

Commercial 51 74 201 225 232 346 600

Residential 0 0 0 0 0 0 20

Total 552 739 1,009 1,116 1,207 1,503 3,539

Based on information contained in the “Technical Support Document: Additional Threshold Analysis Greenhouse Gas Tailoring Rule,” October 12, 2011. 

and information retrieved from EPA's enforcement and compliance history online (ECHO) database during January 2010. ECHO is a computer-data based 

created and maintained by the EPA that contains source-specific data submitted primarily by state and local environmental agencies. See http://www.epaecho.gov/echo/index.html. 

 

21 GHG threshold options are all based on tpy CO2e.