P.1 

OAR Box 1840 

Prepped by Ollie Stewart 

Document Number: 

27) IV-H-33 

Docket Number: 

A-90-37 

Printed 11/14/2008 1:25:30 PM Sheet 27 of 27 
iiuv-u r— ttxiviti. 

P.2 

m- It> 

To: 

Fox#: 

From; 

P.01/18 

8A\ r\. 

FAX TRANSMISSION 

OFFICE OF INFORMATION AND ReeuLAToav AFFAIRS 

OFFICE OF MANAGEMENT AND Bu&eer 

NATURAL RESOURCES, ENS** AND AGRICULTURE BRANCH 

725 17th Street, NW, Room 10202 

Washington, bC 20503 ' 

Office: 202-395-3084/Fax: 202-395-7285 

A-90-37 

IV-H-33 

) Art Fraas 

) Rich Theroux 

) Jim Laity 

) Amanda Lee 

T ^ 4 Amy Farrell 

) Bryon Allen 

) Margie Malanoski 

) David Rostker 

) Ruth Solomon 

) Edmond Toy 

bate; 

Pages: 

\\\n\VL' 

W_ , including this cover sheet. 

Comments: 

\l^% 'will Co/w-C t n ~? 

FAXSHEeTJMttJ 
P.3 

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October 23, 2002 

example, §52.21(b)(48)), and will be based on your postchange design and maximum expected utilization rate less any 

amount of emissions that could have been accommodated .during 

the selected 24-month baseline period and is not rjTj- <l(Jr\^j 

""-— -——_ -

afcti-ib-tbablcrelated to the change. Accordingly, you will 

calculate the unit's projected actual emissions as the 

product of: (I) the hourly.emissions rate, which is based on 

the emissions unit's operational capabilities following the 

change(s), taking into account enforceable restrictions that 

could affect the hourly emissions rate following the 

change(s); and (2) projected level of utilization, which is 

based on both the emissions unit's historical annual 

utilization rate and all available information regarding the 

emissions unit's likely post-change capacity utilization. 

In calculating the projected actual emissions, you should 

consider both the expected and the highest projections of 

the business activity that you expect could be achieved and 

that are consistent with-aay information your company 

publishes for business-related purposes such as a 

stockholder prospectus, or applications for business loans. 

From the initial calculation, you may then make the 

appropriate adjustment to subtract out any portion of the 

emissions increase that could have been accommodated during 

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lateral-and Deliberativa Draft- Do not quoto, cite, copy,, or distribute. 

. /v-eafiaLuJJ-M-iuflj^roject, the baseline actual emissions is equal 

to 0 if you have-not yet begun operation of the unit, and is 

equal to the unit's potential to emit once it has begun to 

operate. 

*_>§. Am I able to apply today's changes for calculating the 

baseline actual emissions to other major NSR requirements? 

No, as stated in section II.AT, you are only allowed to 

use todayfsthe new baseline methodology in today's rule for 

three specific purposes involving existing emissions units 

•(•other- -than an EUSGB**)—as follows.— 

• For modifications, to determine a modified unit's prechange baseline actual emissions as part of the new 

"actual-to-projected-actual" test.-

• For netting, to determine the pre-change actual 

emissions of an emissions unit that underwent a 

physical or operational change within the O 

contemporaneous period. You may select^baseline 

" ' ) \ 

periods for each contemporaneous increase or decrease. 

• For PALs, to establish the PAL level. 

If you determine that the modification of your source 

is a major modification, you must revert to using the 

existing definition of ^actual emissions" to determine your 

source's actual emissions on a particular date to satisfy 

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• "'• '..• :••>'••'.':-.^,\'^!S^.i^s 

Internal, and'Deliberative Draft- DO not quote, cite, copy, or .distribute.' 

October 29, 2002 

Today's new requirements require that yoxi toVelect. 

grthe same single consecutive 24-month period within the 10-

year look back period to calculate the baseline actual 

emissions for eachall existing emissions unit that will be 

affec.fce._-bv the prcnec-.changed. [See, for example, new 

§52.21 (b) (48) (ii) (e.) .] It folluwsThe result will be that 

the baseline actual emissions for each affected pollutant 

al&o mustwill be based on the same consecutive 24-month 

period as well. 

You will have the option to select the single 24-month 

period that best represents the collective level of 

operation (and emissions) for your existing emissions units. 

If a particular existing emissions unit did not yet exist 

during the 24-month period you select to calculate the 

baseline actual emissions, you must count that emissions 

unit's emissions rate as zero for that full period of time. 

If an emissions unit operated for only a portion of the 

particular 24-month period that you select, you must 

calculate its average annual emissions rate using an 

emissions rate of zero for that portion of time when the 

unit was not in operation.— 

For new emissions units (a unit that has existed for 

less than two years) that will be affectedchanaed by the 

68 

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October 29, 2002 

to take advantage of Lhe new procedure, you will also be 

required iv track the post-changebefore proceeding with 

construction. Second, we are requiring EUSGUs that use 

projections for covered projects to send a copy of their 

tracked emissions,to theifpermitting authority, without 

regard to whether these emissionsMihave increased bv a 

significant-amount or exceed their projections. The effect 

of this consolidation is that we make minor changes to the 

existing procedures for EUSGUs. For example. EUSGUs must 

project emissions on a 12-month baBis, rather athan the 

current approach of projecting average annual emissions-;—in 

tons per yeai, from units that are modified1 to ensure that 

the .UCW eniib&xoas do iaot"M.euieaent for the two years 

immediately following the change. Also. EUSGUs need only 

make and report a projection when there is a reasonable 

possibility that the given project mav result in a 

significant emissions increase (or a significant net 

emissioi-s-incTea.se) over the'baseline actual emissions for 

any emis&lons unlfc-r"—[See, for example, new 

S52.21(r) (G) (ii).]—Also, if the m.ifcsr collective annual 

eidnssioiia -ahows that there is -a significant act emissions 

increase at the source,—and hence, a major mudification,—yotr 

must i-eport this Lu youi reviewing authority and be prepared 

41 

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October 29, 2002 

the presumptive time period from which you may establish 

your baseline actual emissions, the new procedures should 

reflect the emissions levels that occur during a normal 

business cycle, without requiring you to demonstrate to your 

reviewing authority that another period is "more 

representative of normal source operations." 

Commenters also believe that the current methodology 

requires many changes made to existing equipment to go 

through major NSR, without taking into account operating 

history, even when such changes will not result in increased 

pollution to the environment. Accoid-jgiqlr, toQur new 

applicability reauirements address these commenters' 

concerns, and fcowill focus limited resources more 

effectively, we have set forth today's new applicablity 

requirements •. 

We are also modifying the way existing units( other 

"than EUSGUs nuav determine whether their emissions will 

Svallowinq them to use projected actual emissions 

for purposes of this determination. Under this approach, in 

circumstances where there is a reasonable possibility that a 

project that is not part of a major modification mav result 

against the PSD increments, and we continue to require its 

use for such purposes. 

36 
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October 29, 2002 

must send a copy of the projections and other 

infprmation tfo their "reviewing authority make cy&ry 

I 

detejiminatioxibefore beginning actual construction, 

If. for a project at an existing emissions unit at a 

major stationary source, you elect to use the actualto-projected-actual emissions test, we are also 

requiring vou to maintain information on your, postchange emissions, for 5 years following a physical or 

operational change, or in some cases for 10 years 

depending on the nature of the change. If your„_annual 

emissions exceed the baseline actual emissions bv a 

significant amount and also exceed vour projection, vou 

must report this information to vour reviewing 

authority within 60 days after the end of the calendar 

year. 

EUSGUs using the actual-to-projected-actual emissions 

test must report their post-change emissions to 

r 

reviewing authorities within 60 days after theimend of 

the calendar year without regard to whether such 

emissions exceed the baseline actual emissions or 

projected actual emissions. 

Instead of projecting your post-change emissionsr all 

existing emissions units mav instead project post54 
. IUV-K J I -CKVOri. 1 <4;

 < ^ 

P.07/18 

P.9 

Internal, and Deliberative Draft- Do not quote, cite , copy, or distribute. 

October 29, 2002 

must send a copy o f th e projection s and othe r 

i n f <prmation t_b thei r 'reviewing authorit y make evar y 

4 

determinationbefore beginning actual construction. 

If. for a project at an existing emissions unit,at a 

ma^or stationary source, you elect to use the actualto-projected-actual emissions test, we are also 

requiring vou to maintain information on your postchange emissions, for 5 years following a physical or 

operational change, or in some cases for 10 years 

depending on the nature of the change. If vour annual 

emissions exceed the baseline actual emissions by a 

significant amount and also exceed vour projection, vou 

must report this information to your reviewing 

authoritv within 60 davs after the end of the calendar 

EUSGUs -using the actual-to-projected-actual emissions 

test must report their post-change emissions to 

reviewing authorities within 60 days after the end of 

the calendar year without regard to whether such 

emissions exceed the baseline actual emissions or 

projected actual emissions. 

__M_8JH-E_ess^55HB-BTe«Mt-5-2=«S555--ee»«Bes5-^ 

Instead of projecting your post-change emissions, all 

existing emissions units mav instead project post54 
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To; 

Fox# 

From: 

-_^___H_l_Ky 

FAX TRANSMISSION 

OFFICE OF INFORMATION ANt> Heeuurow AFFAIRS 

OFFICE OF MANAGEMENT AND BUDGET 

NATURAL RESOURCES, ENe*ev AND AGRICULTURE BRANCH 

72517th Street, NW, Room 10202 

Washington, DC 20503 

Office: 202-395-3084/Fox: 202-395-7285 

bate: 

Pages: 

) Art Fraas 

) Rich Theroux 

) Jim Laity 

) Amanda Lee 

t > 4 Amy Farrell 

) Bryon Allen 

) Margie Malanoski 

) David Rostker 

) Ruth Solomon 

) Edmond Toy 

Jil l n, 

16 ., including this cover sheet. 

Comments: 

MX5HEET.I*-
NOU-07-2002 13:02 

' • '.'.: ':J.V '?&-.„• ! '.'•••• •'}; 

P.11 , 

P.02/19 

• 

> 

rV^l'^r.'f 'C' 

^VXntMMi/'aad'DeiiberativB^raft- Do not quote/ oite , copy, or distribute.' 

[•}£%!J;$$$*Zr/<.-:\'i.'r.' ..''•' . .'". October 2J, 2002 

.V'the unit's 24-month baseline period and is unrelated to the 

change. Once the appropriate subtractions have been made, 

the final value for the projected actual emissions, in tons 

per year, is the value that you compare to the baseline 

actual emissions to determine whether your modification 

project will result in a significant emissions increase. 

The adjustments, to the pfojection• of projected actual 

emissions allows you to exclude from your projection only 

the amount of the emissions increase that is not 

07 r«Ulsod(T ) to the physical or operational 

change(s). In comparing your projected actual emissions to 

the units' baseline actual emissions, you only count 

emissions increases that will result from the construction 

project.—r For example, as with the electric utility 

industry, you may be able to attribute a portion of your 

emissions increase to a growth in demand for your product if 

you were able to achieve this higher level of production 

during the consecutive 24-month period you selected to 

establish the baseline actual emissions, and the increased 

demand for the product is unrelated to the change.— 

For Clean Units, if a given project can be constructed 

and operated at a Clean Unit without causing the emissions 

unit to lose its Clean Unit status, then no emission^ 

73 
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October 29, 2002 

increase will occur. 

For new units/ however, you must continue to calculate 

post-change emissions on the basis of a unit's PTE 

(including lower enforceable levala when applicable).— 

3£. Will my projection of projected actual emissions become 

an enforceable emission limitation ae suggested in the 1998 

NOA?-

No, we did not adopt a requirement-

&&'$ * 

;ld eaLablj 

your pi'ojeetion of projeeted-actua i emission^ as a federally 

enforceable limitation-.—Notwithstanding- the febsence of such 

an earfQiimeablB" restrictionsuch a requirement/. $ 

you ar e an existin g emissions unit((other t2ian a EUSGDland JSGU)< 

your construction project results in both-a significant 

emissions increase and a significant net amissiona-increase 

at the? ma-ior staLionarv aouxaean increase in annual 

emissions that exceeds the baseline actual emissions bv a 

sicrnificant amount, and differs from your preconsLruction 

pro j ection of post-chancre emissions that you were required 

to calculate and maintain, records of. then you must report 

this increase to your reviewing authority, eon-sistent with 

today's representative-actual-annual emission testa; EUflQCTs 

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. . • .' i 

Internal «nd Deliberative Draft* Do not quote, cite, copy,, or distribute. 

•'•\j,K:.: ;: -,-\ 0ctob«r2S|, 2002 

report annually their post-change annual emijaion 

reportsemissions to the. reviewing authority under the net* 

tgEPCO Lest-—-flee 3ectioi.anv occurrence of a significant 

increase will be covered under that report for the affected 

calendar year. See section II.D.6 of this preamble for a 

more detailed discussion of the reporting requirements. 

473-

 Ho w

 &° * determine how long my projection of projected 

actual-post - change emissions will be tracked to ensure that 

my project is not a major modification? 

Generally, your projection of projected actual 

emissions must be tracked against your facility' siMpostchange emissions for 5 years following completion of the 

changes whether you are an EUSGU or other type of existing 

emissions unit. We will presume that any increases that 

occur after 5 years are not associated with the physical or 

operational changes. However, you may be required to track 

emissions for a longer period of time under aertainthe 

following circumstances. That is, If you are an existing 

emissions unit fulllll f^ilESwiliSBffirafr and one of the effects 

of your physical or operational change(s) is to increase a 

unit's design capacity or PTE, ouch that a _Ujjuirica.iL 

emij,^iuua incxease cculd result, but you da UOL belie ne LhaL 

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October 29, 2002 

the new capacity or PTE will be fully utilised (so as not Ic 

cause1-a•significant net emissions increase),you must.track 

your emissions for a period of io years after the completion 

of the cuiij true Lion project. This extended period allows 

for the possibility that vou could end up using the 

increased capacity ngare thafen you added via the physical or 

upeiaLlonal changes could be fully- utilized during a normal 

bas-itiess cycle.—Likewise,—if-you-axe a EU3QU, you'may be 

required to track your emissions for a period-of-10 years, 

if the reviewing- authority determines that this longer 

period is more representative of-normal1 source operations•.-

€-rpro^ected and such use might lead to significant emissions 

increases. 

4. What are the reporting and 

for modiffc^ion projects^ 

When, according- to your best calculations1.-, the physical 

or operational changes'you are planning to make to one OJ 

more existing emissions'units (other than an EUflGU1)

--qt' yoar 

majoi staLiunary -sourccReportihg and recordkeeping for a 

project is recfuired when three criteria are met: 1) vou 

elect to project post-change emissions rather than use PTE; 

2) there is a reasonable possibility that the project will 

" —-r-r^ —mMmmm\mmmmm^SSS^Lamm^m\\m-mt,tmmmmWS^\,^S,^S;S^Kt^La\m\mm^ X '"• •ka _S_eS-HP-^Sfe-SS^^CP-BEC-S5S 

result in a significant emiaaions increase: and 3) the 

I 

recordkeeping 

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October 29, 2002 

above, you are also obligated to ensure that the necessary 

emissions information you are required to maintain is 

available for examination upon request by the reviewing 

authority?— 

Existing EUflGUs will have the-same repeating and 

iccordH-ecpincj xequiiements that existed undei; the actual-tolepieaentaLl-ve-actual anhwal emissions tesL, except that you 

will be ie4uired to .submit a notice Lo your reviewing 

•authority before beginning actual const-, uction.—See • the 

dissuasion earlier on this-issue in fleet-ion II. A. of- this 

jyjieamble. 

•? or the general public. 

j|. How do today's changes affect the netting methodology 

for existing emissions units (other than EUSGUs)? 

If your calculations show that a significant emissions 

increase will result from a modification, you have the 

option of taking into consideration any contemporaneous 

emissions changes that may enable you to "net out" of 

review, that is, show that the net emissions increase at the 

major stationary source will not be significant. The 

contemporaneous time period will not change under the 

Federal PSD program as a result of today's action. That is, •? 

creditable increases and decreases in emissions that have , j 

79 •' 
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i\/y October 29, 2002 

n^ whether a significant net emissions increase will occur at 

the major stationary source, will not change as a result of 

today's final rulemaking, f However/)today 's rulcmakii-c; • 

codifies the presumption1established under the 1392'WEPCO 

aiuefidiiiei-ts,. whichthe rule provides that for an existing 

EUSGU you may calculate the baseline actual emissions as the 

average annual emissions (tpy) of the emissions unit using 

any 2-year period out of the 5 years immediately preceding 

the modifications—Thlb Dre&Lmmtioii (This was, set out as a 

presumption in the preamble for the 1992 WEPCO amendments) . 

This rule recognizes the nature of utility operations 

without compromising the regulatory language -that •••requires 

t-hat t-he 2-year period used in defining the baseline actual 

emissions be rcureaentaLive of "normal" oueratiunsordinary 

variability in demand for electricity. [See, for example, 

new §52.21 (b) (21) (ii) J 

For example, as a system a utility's "normal" 

operations7means directly responding Lo a demand for 

electricity.—fta cold winter or hot summer will result in 

high levels of "normal" operationsdemand while a relatively 

mild year will produce lower "normalff operationsdemand. By 

allowing a utility to use any consecutive 2 years within the 

past 5, the rule better considersrecoo/nizes that electricity 

82 

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demand and resultant utility operations fluctuate in 

response to various factors such as annual variability in 

Climatic or economic conditions that affect demand, or 

changes at other plants in the utility system that affect 

the dispatch of a particular plant. By em.aai_dir.eral lowing 

utilities to use as a baseline for a utility to any 

consecutive 2 years in the last 5 vears. these types of 

fluctuations in operations can be more realistically 

considered, with the result being a baseline more closely 

representative of normal operation. 

ran 

f aurmal uperafcion. . ,/ . ,* J 

; ydu,wiii==g_ajLiiiuH to mavia L..C uppuitL-uity 

-v. 

A Jliffu^^ •^•^w<- f<rC** <A{*>V\ X. dji+tmi/^ ficvn -t^vrt 

^«-q ^•_--pl^g«- a fl^.>i-juiww+'li«jw fvara- yam? y-nyiawiaa authority -

fchnr nnnthpr haoelino periud UUfdidU Llie Lyfjiga_:-3 voar 

pe3Ei»oeHg.iJ muiu rcproocaitativo of the emiooiono unites— 

wric_2_ffl-y>S-_^>perat.ion.> ...This opportunity is not available under 

the new 10-year look back approach that is -applicable to all 

other eixisti-ug emissions' units when you plan to modify them. 

It ehould-be noted that the "2-year-in-5" baseline 

method applicable to modifications at existing EUSGU does 

not--apply to past modifications at BUflGU for the purpose-of 

determining contemporaneous emissions changes:—Thisposition was stated in the 1992 WEP00 rulemaking, and it ia 

not being alLcred in tuday's rulemaking.—flee 57 PR 32323, 

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October 29, 2002 ' M 

the industries analyzed, business cycles differ markedly by 

industry, and may vary greatly both in duration and 

intensity even within a particular industry. Nevertheless, 

we concluded from the study that lo years of data is 

reasonable to capture an entire industry cycle. Comments 

from various industries support a conclusion that a 10-year 

look back period is a fair and representative time frame for 

encompassing a source's normal business cycle. 

We believe that the use of a 10-year look back period 

will help provide certainty to the process and eliminate the 

ambiguity and confusion that can occur when an applicant and 

the reviewing authority' disagree^on what time frame provides 

the period most representative of normal source operation. 

The new requirements also provide certainty to the look back 

period, since there is no opportunity to select another 

period of time outside this 10-year period (see additional 

discussion in ^section II,E.2.) In addition, we have placed 

certain restrictions on when the full 10-year look back 

period may be used. (See fJgection II.E.3.) 

With regard to the concern that industry may try to 

apply the new requirements retroactively to undo current 

industrial Classification (SIC) code for individual industries (OMB, 1987). maiviaual 

96 

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October 29, 2002 

nonattainment area or ozone transport region. (See 61 FR 

38259, July 23, 1996.) However, because we are now beyond 

the point where the November 15, 1990 limit is relevant to 

modifications, we are only applying this limitation ininthe 

netting context with respect to emissions units changed 

within the contemporaneous period fcr a modification. 

4. Why were changes made to the proposed approach for 

establishing baseline actual emissions using a 10-year look 

back? 

Commenters raise specific questions about how to use 

the 10-year look back to calculate an emissions unit's 

baseline actual emissions. Several commenters are concerned 

about how the utilization rate would be considered in the 

calculation. For example, some commenters support the 

proposal to allow sources to use their highest capacity 

achieved during any consecutive 12 months, because it 

provides improved flexibility in establishing a capacity 

level that is representative of normal operations. However, 

other commenters object to using the 12 months with the 

highest utilization. These commenters argue that the use of 

production rates can be unworkable because there is not 

always a clear relationship between production rate and 

emissions, in addition, reliable records may not be 

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October 29, 2002 fan 

extent that the reductions resulted hef conditions that are 

enforceable aa a •practical matterlimitations. 

5. How does the change in the baseline period affect 

related requirements regarding protection of air quality? 

a. How does the extended baseline period conform with the 

special modification provisions under sections 182(c) and 

(&) of the Act? 

Most commenters feel the proposed extension of the look 

back period fits within the design and intent of the special 

modification procedures set forth in sections 182(c) and (e) 

of the Act, applicable in serious, severe and extreme ozone 

nonattainment areas. However, one commenter representing 

State and local air pollution control agencies considers the 

new requirements to be in significant conflict with the 

special modification procedures contained in those sections 

of the Act. The commenter indicates that this conflict 

could be resolved by deferring to relevant requirements for 

modifications in serious, severe and extreme areas. The 

commenter adds that while NSR programs are tools to attain 

and maintain compliance with the NAAQS, they should not be 

available to undermine specific statutory and SIP 

requirements designed to resolve nonattainment problems. 

We disagree with the commenter's concern that the use 

106 

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October 2*, 2002 ^ 

baseline actual emissions (for purposes of determining 

whether a physical or operational change will result in adf 5KYU/"K>I(-' 

emissions increase) will cause any adverse environmental 

impacts.— 

6. why was the contemporaneous period for netting not also 

changed to a 10-year look back period? 

In the 1996 NPRM, we indicated that we were not 

proposing to extend the 5-year contemporaneous period along 

with the proposed 10-year look back period associated with 

the establishment of baseline actual emissions. (See 61 FR 

38259, July 23, 1996.) We did, however, solicit comments on 

the effect of the' differing look back periods and any 

reasons why these periods should be the same. Commenters 

responded in a variety of ways to our request, with no clear 

consensus as to whether it would be appropriate to establish 

a uniform look back period. One commenter supports the 10-

year contemporaneous period for reasons of consistency. 

Other commenters believe that it was reasonable to use two 

different time frames. Some commenters support retaining 

the 5-year contemporaneous period because changing it could 

have adverse effects on existing permit determinations. 

Several commenters support the selection of a different 

contemporaneous time frame other than the existing 5-year 

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period, but differed in their recommendation for changing . 

it. One suggests giving the source the option of choosing 

either a 10-year or 5-year contemporaneous period. Another 

commenter believes that a l-year period would reduce 

confusion. Finally, another commenter proposes a 5-year 

contemporaneous period that would not mandate that 

consecutive 5 years be considered. 

We do not believe that there is a compelling reason to 

change the existing 5-year contemporaneous period. The look 

back periods serve different purposes and need not be the 

same in order to effectively implement the NSR program 

objectives. States retain the flexibility in defining a 

different contemporaneous period under SIP-approved NSR 

programs, and may use that flexibility to adjust the 

contemporaneous period if they believe that a different 

period is more appropriate,for their purposes under the new 

applicability requirements. [See, for example, 

§51.166(b)(3)(ii).] Therefore, under today's new 

requirements, we have not changed the 5-year contemporaneous 

period under the Federal PSD program. It should be noted ur r I 

that for purposes of determining the baseline actual

 4* C/fc-*^ 

emissions of a contemporaneous change in emissions from an 

emissions unit that was an existing unit at the time of the 

ill 
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October 29, 2002 

apply the causation provision as originally contained in the 

WEPCO amendments. ..Both the statute and implementing, 

regulations indicate that there should be a causal link 

between the proposed change and any post-change increase in 

emissions, that is, "...any physical change or change in the 

method of operation that would result in a significant net 

emissions increase..." [emphasis added]. [See, for example, 

existing §52.21(b)(2)(1).] Consequently, under today's new 

rules, when a projected increase in equipment utilization is 

in response to a factor such as growth in market demand, you 

may subtract the emissions increases from the unit's 

projected actual emissions if you can show that: (1) the 

unit could have achieved the necessary level of utilization 

during the consecutive 24-month period you selected to 

establish the baseline actual emissions; and (2) the 

<_\»r«riM , 

increase is not a11xibutablerelated to the physical or 

operational change(s) made to the unit. [See for example, 

new §52.21 (b) (41) (ii) (c) .] 

On the other hand, demand growth can only be excluded 

to the extent that the physical or operational change is not 

aLtributablerelated to the emissions increase. Thus, even 

if the operation of an emissions unit to meet a particular 

level of demand could have been accomplished during the 

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determining a-significant emissions aud one for determining 

a significant net emissions increase) presents an 

unreasonable burden-.—Moreover, we have retained a different 

methodology for the WEPCO test and fur netting for EUOQUa. 

We are not aware of any absurd results or undue bmrden 

placed on EUSGUs from the WEPCO- rules. Accordiiigly, we are 

. noL ej.tending the "actual to fu-ture annual"' methodology' for 

computing contemporaneous increaset. -or decreases from Hie 

other emissions units- at a manor stationary sourceAs stated 

previously, we did not specifically request comment o$. this 

issue and we have no plans to apply this test to netting at 

this time. AIAZS /jJ^io® & wk <$*+ 4A'*W A^I ^ e*| 

ll. Should we impose an enforceable projected actual 

emissions level? ~~lf r& 

Some commenters on our 1996 proposal support the C^f\lv^L 

establishment of an enforceable limitation on the modified 

source's projected future emissions level. Other commenters 

support our specific proposal in the 1998 NOA to use the 

projection of projected actual emissions as a temporary cap 

for the emissions units involved in the modification 

project, that is, an enforceable 10-year emissions level. 

On the other hand, many other commenters oppose the 

concept, citing various reasons for their opposition. These 

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included concerns that it would become a d_s facto baseline 

for any additional permitting and create additional 

enforcement liability, usurp State prerogatives, be 

inconsistent with the Clean Air Act, and require enforceable 

restrictions for too long. A few state and local air 

permifc.timareviewing agencies indicate that they did not have 

the resources to adequately administer a program that would 

require permits to be issued for every physical or 

operational change at a major stationary source.-

Today's new requirements follow the 1996 proposal. You 

will not be^required to make the projected actual emissions 

protection*' through a permitting action. After considering 

the\comments received, we are concerned that such a 

requirement may place an unmanageable resource burden on 

-.ermittim reviewing authorities. We also believe that it is 

not necessary to make your future projections enforceable in 

order to adequately enforce the major NSR requirements. The 

Act provides ample authority to enforce the major NSR 

requirements if your physical or operational change results 

in a significant net emissions increase at your major 

stationary source. 

12. Why are modified sources that are not considered major 

modifications not required to submit annual reports of 

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» 

records if vou elect to use the actual-to-pro-)ected-act 

emissions test to calculate vour emissions increase from the 

pro-ject. Second, you are only reguired to keep the records 

if there is a reasonable possibility that vour project micfot 

result in a significant emissions increase. Finally, you 

only need keep those records for projects that are not major 

modifications. 

We also considered requiring you to submit an upfront 

notification to your reviewing authority, but concluded that 

this would result in an unnecessary paperwork burden (except 

EUSGUs) . We anticipate that a large majority of the 

projects that are not major modifications may nonetheless be 

required to undergo a permit action through States' minor 

NSR permit programs. In such cases, the minor NSR 

permitting procedures could provide an opportunity to ensure 

that you and your reviewing authority agrees with your 

emission projections. Requiring a separate notification 

would not provide the reviewing authority with any 

additional information in such circumstances. Accordingly, 

we believe today' s requirements provide permiLtincireviewing 

agencies with the ability to obtain all the.information 

necessary to ensure compliance. 

13. Why are we promulgating^ajdifferent applicability test 

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. October 29, 2002 • ': '" "^'TM^'-

may be desirable to have the same level of oversight on 

construction and modification for any type of emissions 

units, this approach is impractical due to resource 

constraints at reviewing authorities.—If all source 

categories were required to submit a notice to the reviewing 

auLhority, we are concerned Lhat the reviewing authority may 

overlook iiuLiuea submitted by EUOOUs.—Thua, we are choubing 

Lo focus reviewing auL..oiilicar rebuurutJ on BUSOU becau.se 

Lhey represent a proportionally higher amount uf emissions 

in most Qtate -emissions inventories -than -any other • category 

of entxasiona units. 

Te..L tfaa I'l^^-jd FroAi Here.—3: 

!Podayf s-fdnal-rul-e contains recurdkeeping and1 reporting 

requirements for existing emissions units rather than- the 

annual reporting requirements as required for EUSOUa.—ftsstated earlier, we think thai- -either-"approach provides an 

effective mec.jBaiiism-for permitting-author!tics to enfurce 

the major-NSR requirements.—However1,

- again, because EfrggUs 

represcnL a proportionally higher •percentage of State 

emissions ••inventories, we believe'that it i& beneficial for 

permitting authorities to receive annual emissions 

information from these sources tc • con-firm Lheir compliance 

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f 

o< 

''believe PALs based 

,*1 and assure envisrbnmi 

affected sources had adequate 

/ . .ferol riaftfuijemeTifec| . Therefore./we intend in the 

near future to~-propose a rule soe^_rg±<aa 11 v afjdrAegriawr PALs 

I 

Analogous to what the PAL does for facilities, the 

Clean Unit tgest sets emissions limitations or work practice 

requirements in conjunction with BACT, LAER or Clean Unit 

determination and identifies any physical or operational 

characteristics that formed the basis for the BACT, LAER or 

Clean Unit determination for a particular unit. The Clean 

Unit tgest recognizes that when^ you go through major NSR 

review (including air quality review) and install BACT or 

LAER or comparable technology, then vou may make any 

subsequent changes to the Clean Unit without triggering an 

additional major NSR review as long as there is no need for 

a change in the emissions- limitations or work practice 

requirements in the permit for the unit adopted in 

conjunction with BACT, LAER or Clean Unit determination or 

to alter any physical or operational characteristics that 

formed the basis for the BACT, LAER or Clean Unit 

determination. Therefore, for Clean Units, given that the 

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