Chapter 13
Startup, Shutdown and Malfunction

Contents
13.1	General	2
13.2	Treatment of Malfunctions and Affirmative Defense	6
13.3	Startup and Shutdown	16


General
Commenter 10681 agreed with the EPA's proposed approach to include all emissions during startup, shutdown, and partial load in determining the emissions rate. The commenter referenced Washington's greenhouse gas emission performance standard regulation (WAS 173-407, Part II) requirements.
The EPA acknowledges the commenter's support. The EPA's final action establishes standards that apply at all times. In establishing the standards, the EPA has taken into account emissions during startup and shutdown periods. Specifically, startup and shutdown periods are included in the compliance calculation as periods of partial load.
Commenter 9512 noted that the proposed rule is incomplete and inadequate with respect to SSM provisions of proposed subparts Da and KKKK. Commenter 9512 stated, "EPA's intended approach to startup, shutdown, and malfunction events, as described in the preamble to the Proposed Rule and discussed in the foregoing comments, is only reflected fully in proposed subpart TTTT. The proposed alternative additions to subpart Da do not make any changes with respect to the way malfunctions are addressed under other, existing provisions of subpart Da and under subpart A. In contrast, the proposed alternative additions to subpart KKKK exempt the proposed CO2 provisions from portions of subpart A that address SSM events (see proposed Table 3, 79 Fed. Reg. 1510, stating that sections 60.8 and 60.11 do not apply to the CO2 emission standards), but no affirmative defense language has been proposed." Commenter 9512 further stated, "If EPA decides to address CO2 emissions at new and modified EGUs through revisions to subparts Da and KKKK, EPA must re-propose those revisions for public comment with clear and unambiguous indications of how SSM events will be addressed under the proposed rules."
As explained in section III.B of the final rule preamble, the EPA is combining the steam generator and combustion turbine categories into a single category of fossil fuel-fired electricity generating units for purposes of promulgating standards of performance for GHG emissions. The standards of performance for CO2 emissions will be codified in a new 40 CFR part 60, subpart TTTT. Because this comment regards the SSM provisions associated with the co-proposed approach of codifying the standards of performance in the 40 CFR part 60, subparts Da and KKKK, which the EPA is not finalizing, further response is not provided. 
Multiple commenters (7977, 9471, and 9512) stated that the EPA has not sufficiently supported its treatment of emissions during startup, shutdown, and malfunction periods in the rulemaking.
Commenter 7977 expressed "serious and significant concerns regarding the practical ability to monitor emissions during periods of startup, shutdown, and malfunctions." 
Commenter 9471 noted that "during periods of startup and shutdown, although weighted mass emissions are low, the emission rate based on the ratio of mass emissions to electric generation can easily exceed the 1,000 lb/MWh standard."
Commenter 9512 stated that "EPA has failed to account adequately for emissions that occur during SSM periods, consistent with the language and intent of CAA NSPS." 
EPA disagrees that it has not adequately explained the basis for its decision to promulgate standards that apply at all times, including during SSM events.  See section X.A and J.1 of the final rule preamble for the EPA's response to these comments.
Commenter 9512 noted that it can be "unclear whether a condition that leads to excess emissions should be characterized as a startup or shutdown event or a malfunction event. Without a clear demarcation (both in EPA regulations and in practice), the EPA may be analyzing data sets that exclude events that were treated as malfunctions, but that the EPA would say should be included in calculating average performance as startup or shutdown conditions."
The terms "startup," "shutdown," and "malfunction" as defined in section 60.2 of 40 CFR part 60, subpart A (General Provisions), enable sources subject to subpart TTTT to determine whether specific periods of operation are periods of startup, shutdown, normal operation or malfunction. See also section X.A of the final rule preamble.
Commenter 9512 stated that the EPA has not "justified its rejection of relief from numerical emission limitations that it has provided in NSPS for decades." Commenter 9512 noted the following:
   oo "court decisions both before and after the Clean Air Act Amendments of 1977...have affirmed the appropriateness of including special SSM provisions in standard issued under section 111"
   oo "an emission limitation that applies during SSM events does not meet the requirement of CAA section 111(a)"
   oo courts have reached similar conclusions in Clean Water Act decisions 
EPA acknowledges that in the past it addressed emissions during SSM events differently in regulations it issued pursuant to CAA section 111, CAA section 112, and CAA section 129.  As noted by the commenter, the General Provisions applicable to NSPS have historically not required sources to meet the same emission limits during SSM events as during other periods of operation, unless otherwise specified in the applicable standard.  (See, 40 CFR section 60.8(c)).  Likewise, EPA acknowledges that some prior court decisions support the general proposition that emission limitations must be reasonable and appropriate, including limits that apply to emissions during modes of source operation such as startup and shutdown.  (See, e.g., Portland Cement Ass'n v. Ruckleshaus, 486 F.2d 375 (D.C. Cir. 1973)). EPA does not, however, agree with the commenter's extrapolation from these past rulemakings and decisions that emission limitations promulgated under CAA section 111 must contain exemptions or other special treatment for emissions during SSM events.  The D.C. Circuit's decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008) vacated the SSM exemption contained in 40 CFR 63.6(f)(1) and 40 CFR 63.6(h)(1).  Since that decision, EPA's proposed approach to emissions during SSM periods has been used consistently in CAA section 112, CAA section 111, and CAA section 129 rulemaking actions.  (See, e.g., National Emission Standards for Hazardous Air Pollutants From the Portland Cement Manufacturing Industry and Standards of Performance for Portland Cement Plants, 75 FR 54970 (Sept. 9, 2010); Standards of Performance for New Stationary Sources and Emission Guidelines for Existing Sources: Sewage Sludge Incineration Units; Final Rule, 76 FR 54970 (March 21, 2011) National Emission Standards for Hazardous Air Pollutants from Coal- and Oil-fired Electric Utility Steam Generating Units and Standards of Performance for Fossil-Fuel-Fired Electric Utility, Industrial-Commercial-Institutional Steam Generating Units; Final Rule, 77 FR 9304 (February 16, 2012)).  Under this approach, EPA sets emission standards that apply at all times, including during predictable modes of operation such as startup and shutdown.   See also Preamble section X.A.
Commenter 9512 stated that EPA is wrongly interpreting the court's decision in Sierra Club v. EPA concerning the requirement for continuous emission limitations in a NESHAP under section 112 to apply to an NSPS under section 111.  The commenter noted that the court's decision only addressed the issue of exemptions for emissions during SSM events for sources in regulations pursuant to section 112, not section 111. In addition, the commenter stated that the court's decision only held that a blanket exemption in the General Provisions for NESHAPS was inconsistent with the requirements of section 112. The commenter thus asserted the court's decision has no bearing on the requirements of section 111.
 EPA disagrees that the Sierra Club v EPA decision has no bearing on section 111 standards.  EPA believes the reasoning of the D.C. Circuit's decision in Sierra Club v. EPA applies not only to standards EPA promulgates under section 112, but also to standards under section 111.  As explained in the proposal for this action, the D.C. Circuit's decision vacated the SSM exemptions in the General Provisions applicable to many NESHAP in 40 CFR section 63.6(f)(1) and 40 CFR 63.6(h)(1), holding that under section 302(k) of the CAA, emission standards or limitations must be continuous in nature and that the exemption for emissions during SSM events violated the CAA requirement that some section 112 standard apply continuously.  EPA believes that the logic of the court applies with equal force to the requirements of section 111.  Section 111 requires EPA to impose a "standard of performance" on affected sources, and section 111(a)(1) specifically defines "standard of performance" as a standard "which reflects the degree of emission limitation" achievable through BSER.  Similarly, section 111(b)(B) directs EPA to revise a NSPS when "emission limitations . . . beyond those required by the standards" are achieved in practice.  Both provisions define a standard of performance based, in part, on the key requirement that it constitute an "emission limitation."  Section 302(k) explicitly defines the term "emission limitation" to be a requirement "which limits the quantity, rate, or concentration of emissions on a continuous basis, including any requirement relating to the operation or maintenance of a source to assure continuous emission reduction."  Consistent with the decision of the D.C. Circuit in Sierra Club v. EPA, EPA interprets section 111 to require NSPS that impose standards that apply to affected sources at all times, during all modes of source operation without exemptions.  This interpretation is further supported by section 111(h) which authorizes EPA, under appropriate circumstances, to impose "a design, equipment, work practice, or operational standard, or combination thereof, which reflects the best technological system of continuous emission reduction."  The definition of the term "technological system for continuous emission reduction" in section 111(a)(7)(B) includes "a technological system for continuous reduction of the pollution generated by a sources before such pollution is emitted into the ambient air."  In both of these provisions, the statute explicitly describes the standard as "continuous." Thus, even if an NSPS were composed of different limits or forms of control, section 111(h)(1) requires that the standard must reduce emissions on a "continuous" basis.  Even if section 111 were ambiguous on this point, EPA believes it is reasonable to interpret section 111 to preclude any exemptions from NSPS for emissions during SSM events, just as the D.C. Circuit interpreted section 112 to preclude such exemptions.
        To the extent that the commenters argue that the Sierra Club v. EPA court vacated the General Provisions applicable to emissions during SSM events because they were based on a "general duty" clause rather than a continuously applicable section 112 standard, EPA agrees that the court found that the "general duty" was not a section 112-compliant standard.  EPA does not claim that the Sierra Club case constrains its authority to prescribe standards under section 111 that impose different numerical limits or different forms of controls during different modes of source operation, under appropriate circumstances.  Section 111(h)(1) expressly authorizes such an approach, under certain conditions, so long as the resulting standard applies continuously and meets the relevant stringency requirements for a standard of performance under section 111.  As explained in section V.J.1 and section X.A of the Preamble, however, EPA has determined that it is not appropriate to set alternative standards for emissions during startup and shutdown, nor is it appropriate to include an exemption or other special treatment for emissions during malfunctions.
Commenter 9512 noted that CAA section 302(k) "defines `emission limitation' and `emission standard' to be not solely a numerical limit on the quantity, rate, or concentration of emissions of an air pollutant on a continuous basis, but rather `a requirement' which `limits the quantity, rate, or concentration of emission of air pollutants on a continuous basis."  The commenter thus asserted that "the statute does not say that `requirement' must be expressed as a single, numerical, not-to-be exceeded-at-all times limitation."  The commenter also argued that "a `requirement' that limits emissions `on a continuous basis' does not have to impose the same limitation at all times.  Nor does the form of the limitation have to always be the same."
EPA agrees, in general, that the definition of emission limitation in CAA section 302(k) does not require that all standards must be set only as a numerical limit, or at the same numerical limit applicable at all times.  EPA likewise agrees, in general, that an emission limitation may be comprised of a numerical limit or limits combined with specific control technologies or work practices that apply during certain modes of source operation.  So long as all components of such a continuously applicable emission limitation meet applicable stringency requirements and are legally and practically enforceable, such an emission limitation may be appropriate.  Section 111(h) explicitly authorizes EPA to impose standards that may include different levels or forms of controls that, in combination, provide for continuous emissions control at the level of stringency required for purposes of section 111.  In some circumstances specific alternative numerical limits or control requirements applicable to for periods of startup and shutdown as part of an emission limitation may be appropriate.  In the case of this action, however, EPA has determined that it is not appropriate to promulgate standards that impose different numerical limits, or different forms of controls, for specific modes of operation such as startup and shutdown. Moreover, EPA does not agree with the commenter's arguments that because an emission limitation could include a combination of different numerical limits, technological controls, or work practices, that an NSPS can include an exemption for emissions during startup, shutdown, malfunctions, or any other mode of operation.  EPA has concluded that the court's decision in Sierra Club v. EPA concerning the term "emission limitation" precludes the type of SSM exemptions for which the commenter advocates. Finally, EPA disagrees with the commenters' characterization of the legislative history for section 302(k).  Contrary to the commenters' view, EPA does not interpret the statutory language to apply only to "intermittent" controls, nor does the legislative history support such a narrow reading.  Congress was concerned that emission limitations be continuous so that they achieve the requisite emission reductions and be capable of effective enforcement. See also section X.A of the final rule preamble.
Treatment of Malfunctions and Affirmative Defense
13.1 
Multiple commenters (9660, 9666, and 10100) cited NRDC v. EPA, 749 f.3d 1055 (D.C. Cir. 2014) and asked that the EPA re-evaluate its decision to provide an affirmative defense for violations during malfunctions. .  Commenters took issue with the specific wording of the affirmative defense, the narrow circumstances under which the affirmative defense would be available, and the fact that an affirmative defense would not be allowed given the recent decision of the D.C. Circuit in NRDC v. EPA.  Commenters used these arguments in support of their preferred approaches that would provide either an exemption for emissions during all malfunctions or a numerical limit sufficiently high that it would encompass emissions during all malfunctions. 
The EPA is not including a regulatory affirmative defense provision in the final rule. See section X.A of the final rule preamble for the EPA's response to this comment.
Multiple commenters (10098 and 10239) stated that the DC Circuit's decision in NRDC v. EPA need not affect the affirmative defense in this rulemaking.
Commenter 10098 stated that the "parties' deadline to seek further review has not yet passed" and "as the D.C. Circuit recognized, id. at 18, n.2, the decision appears to be inconsistent with Fifth Circuit's decision in Luminant Generation Co. v. EPA, 714 F.3d 841 (5th Cir. 2013), which affirmed the inclusion of an affirmative defense in a state implementation plan." Commenter 10098 urged EPA to include the defense. 
Commenter 10239 asserted that an affirmative defense for violations during malfunctions is warranted and stated that they "do not believe that the EPA is bound by any judicial precedent that would prohibit it from including in a final rule an affirmative defense for malfunctions."
EPA disagrees with commenters who stated that the decision in NRDC v. EPA, 749 F.3e 1055 (D.C. Cir. 2014) has no bearing on this rulemaking.  In that decision, the court vacated the comparable affirmative defense that EPA had provided for violations due to emissions during malfunction events.  The DC Circuit explicitly held that EPA has no authority to alter the jurisdiction of the federal courts granted by Congress pursuant to sections 113 and 304.  That decision did not turn upon the specific provisions of section 112 and is equally applicable to standards promulgated by EPA under section 111.  Sections 113 and 304 address jurisdiction of the courts for judicial enforcement for violations of all CAA requirements, including judicial enforcement actions for violations of NSPS.  Similarly, EPA does not agree that footnote 2 in the NRDC v. EPA decision noting the existence of a 5[th] Circuit decision pertaining to an affirmative defense in a SIP provision has any bearing upon this action.  Contrary to the belief of the commenters, EPA does not interpret that footnote to indicate any decision by the DC Circuit that an affirmative defense is valid in a SIP provision.  EPA has separately taken action on a petition for rulemaking to address the issue of affirmative defenses in SIP provisions. (See, "State Implementation Plans; Response to Petition for Rulemaking; Restatement and Update of EPA's SSM Policy Applicable to SIPs; Findings of Substantial Inadequacy; and SIP Calls To Amend Provisions Applying to Excess Emissions During Periods of Startup, Shutdown and Malfunction; Final Rule," 80 FR 33840 (June 12, 2015)).  Accordingly, the EPA is not including a regulatory affirmative defense provision in the final rule. See section X.A of the final rule preamble for the EPA's response to this comment.
Multiple commenters (9425, 9591, 10048, 10098, and 10105) agreed with specific aspects of the proposed affirmative defense provision.
Commenters 9425 and 9591 agreed with the EPA's decision to remove the requirement to notify EPA within two days of a malfunction.
Commenters 10048 and 10098 supported the EPA's creation of an affirmative defense for excursions caused by a malfunction of control equipment. 
Comments supporting aspects of the proposed affirmative defense provision are no longer germane to this action. The EPA is not including an affirmative defense provision in the final rule. See section X.A of the final rule preamble for the EPA's explanation for that decision. .
Multiple commenters (3862, 9423, 9512, 9666, and 10098) asked for clarification of or changes to affirmative defense language.
Commenter 3862 asked that the word "violation" be replaced with "prohibition" in the affirmative defense language. 
Commenter 9423 asked that the rule be revised to "allow state rules for affirmative defense that are EPA-approved as part of a SIP to be used in lieu of the federal procedures."
 
Commenter 9512 asked that the requirement in section 60.5530(b) be changed from 45 days to 90 days.
Commenter 9512 stated that "it is not even clear what the affirmative defense covers." Commenter 9512 further noted, that the "affirmative defense is 'to civil penalties that are caused by malfunctions.' (See, e.g., 79 Fed. Reg. at 1449, 1450.) Is the term 'civil penalties,' which is not defined in the Proposed Rule, intended to apply as well to a 'civil administrative penalty' imposed by EPA under CAA section 113(d)? (The term 'civil penalty' in other contexts means only penalties imposed by a court.) Does the affirmative defense apply to 'noncompliance penalties' under CAA section 120 (which apply, inter alia, to noncompliance with a section 111 NSPS)? To meet the purported purpose of the affirmative defense, which is to provide relief from emission limitations that cannot be met at times even with equipment that is properly designed and maintained (see id. at 1449), the affirmative defense would need to apply to civil and administrative penalties, including noncompliance penalties."
Commenter 9512 also asked how the affirmative defense would apply to enforcement actions by state and local governments, or to private citizen enforcement actions under CAA section 304. 
Commenter 9512 asked for an explanation for why the affirmative defense would not apply to injunctive relief. (See 60.5530)
Commenter 9512 asked that affirmative defense be redefined to state that a source "'will not be deemed in violation of' the NSPS for excess emissions or other deviations from the standards, associated with a startup, shutdown, or malfunction event, unless the event, and the source's response to the event, do not meet the criteria spelled out in the regulations." Commenter 9512 noted that, "Configured in that way, this provision for malfunction events should be considered something other than an 'affirmative defense,' such as an 'alternative standard for SSM events.'" Commenter 9512 offered that, "By allowing these SSM considerations and issues to be addressed by an 'alternative standard,' EPA would also circumvent any possibility that its use of the affirmative defense to the SSM provisions in this and other rulemakings could be vacated by a court as beyond the scope of EPA's authority."
Commenter 9512 asked that 60.5530(a)(6) be changed to exclude the language "if at all possible" because it differs from section 60.2, which uses the qualifier "to the extent practicable." 
Commenter 9512 noted that 60.5530 lists items "which may be appropriate considerations in determining whether excess emissions during a malfunction should be considered a violation, but which ought not to be listed as mandatory criteria, all of which have to be met in order for an exceedance to be excused. For example, proposed section 60.5530(a)(1)(i) requires that the excess emissions must have been 'caused by a sudden, infrequent, and unavoidable failure of air pollution control and monitoring equipment, process equipment, or a process to operate in a normal or usual manner'. There is no apparent reason why a 'sudden' and 'unavoidable' equipment failure or process upset leading to emissions greater than the NSPS should be considered a violation of the standards if it is not 'infrequent,' even though it is 'not part of a recurring pattern indicative of inadequate design, operation, or maintenance' and '[c]ould not have been prevented through careful planning, proper design or better operation and maintenance practices.' See 60.5530(a)(1)(ii) and (iv)." 
Commenter 9512 objected to the use of phrases that are subject to a wide range of interpretations:
   oo "How will the enforcement authority, or a judge, determine whether 'proper design' or 'better operation and maintenance practices' could have prevented a malfunction (section 60.5530(a)(1)(ii))
   oo "whether a recurring malfunction is a result of 'inadequate design' (section 60.5530(a)(1)(iv)), 
   oo "whether repairs were made 'as expeditiously as possible' (section 60.5530(a)(2)), 
   oo "whether the source took 'all possible steps' to minimize the impact of the excess emissions (section 60.5530(a)(5)), and 
   oo "whether emissions monitoring and control systems 'were kept in operation if at all possible' (section 60.5530(a)(6))?"
Commenter 9666 asked that the following changes be made:
   oo in sections 60.3350(a)(2) and (7), replace the term "violation" with "malfunction"
   oo in sections 60.3350(a)(3), (4), and (5), replace the term "violation" with "emissions"
Commenter 9666 asked that the following sections be clarified:
   oo In section 60.5530(a)(5), a source must prove that "all possible steps were taken to minimize..." 
   oo In section 60.5530(a)(8), the source must show that "at all times, the affected source was operated in a manner consistent with good practices..."
   oo In section 60.5530(a)(9), the source must submit a written report to the Administrator "with all necessary supporting documentation..."
For section 60.5530(a)(5), commenter 9666 stated that the affirmative defense is more "absolute and extreme" than the CAA. According to Commenter 9666, the CAA specified a level below which further reductions are not required (Sections 112(d) and (f).
For section 60.5530(a)(5), commenter 9666 also asked how this language differs from section 60.5530(a)(3) which requires the frequency, amount, and duration of excess emissions "were minimized to the maximum extent practicable." Commenter 9666 asked that unless EPA "explains what additional showing would be needed by section 60.5530(a)(5), it should be removed from the rule.
For section 60.5530(a)(8), commenter 9666 noted that "affected source" is broader than "affected facility" as defined in 40 CFR 60.2. Commenter 9666 asked that EPA cite the statutory authority that allows them "to shift the focus" of the NSPS from the "apparatus subject to the NSPS to the plat as a whole." Commenter 9666 cited 40 CFR 60.74a(a)(8) was changed from "affected source" at proposal to "affected facility" at final.
For section  60.5530(a)(9), commenter 9666 states that it is "inefficient and burdensome for both sources and regulators, to require a complete justification of the affirmative defense before the enforcement authority has indicated any need for further investigation."
Commenter 10098 asked that EPA include a "procedure to address the affirmative defense through a declaratory judgment/settlement process" so that facilities can "obtain a measure of administrative certainty.
Comments seeking specific clarification of, or revisions to, the proposed affirmative defense provision are no longer germane to this action.  The EPA is not including a regulatory affirmative defense provision in the final rule. See section X.A of the final rule preamble for the EPA's response to these comments.
Multiple commenters (5537, 9512, 9666, and 10031) stated that the EPA must account for malfunctions when setting standards under section 111 and must include emissions attributable to malfunctions in the standards.
Commenter 5537 stated that "an affirmative defense to civil penalties for malfunctions is not appropriate under either a 12 operating month standard or a potential 84 operating month rolling average compliance option." Commenter 5537 noted "for equipment to 'malfunction' long enough to affect compliance with either a 12-month or 84-month standard suggests an extraordinarily long period of malfunctioning time, and could encourage poor operational practice." 
Commenter 9512 noted that the standards are not achievable during malfunctions. Commenter 9512 suggested that EPA "obtain and analyze [deviation reports or malfunction reports from state agencies], in order to assess what type of requirement might reasonably apply to the subject emission units during malfunctions." 
Commenter 9512 also asserted that the EPA has not provided a "factual analysis supporting its new conclusion that NSPS need not include the allowances for malfunctions that were included in dozens of NSPS issued over the past 40 years [Transactive Corp. v. United States, 91 F.3d 232, 237 (D.C. Cir. 1996)] (agency must provide a 'reasoned analysis' to support departing from prior practice)."  
Commenter 9666 stated, "although the Sierra Club decision may draw into question the Agency's ability to exempt periods of malfunction for CAA section 111 standards, it did not authorize EPA to ignore malfunctions in the setting of achievable standards." 
Commenter 9666 disagreed that an 84 operating month averaging period would be sufficient to compensate for emissions during a malfunction. 
Commenter 9666 noted that EPA must address challenges to the achievability of the standard at the rulemaking stage [Duquesne Light Co. v. EPA, 698 F.2d 456, 469 n.14 (D.C. Cir. 1983).
A number of commenters argued that providing an affirmative defense provision applicable to emissions during malfunctions was insufficient and that EPA is required to set standards of performance that either exempt emissions during malfunctions or incorporate emissions that occur during malfunctions as part of the numerical standard.  In support of this premise, commenters relied on a series of court decisions that stand for the proposition that EPA must set reasonable emission limitations on sources (e.g., Portland Cement Ass'n v. Ruckleshaus, 486 F.2d 375 (D.C. Cir. 1973); Essex Chem. Corp. v. Ruckleshaus, 486 F.2d 427 (D.C. Cir. 1973); and Nat'l Lime Ass'n v.  EPA, 233 F.3d 625 (D.C. Cir. 2000)). According to the commenters, these decisions compel EPA to account for emissions during malfunctions in order to set "achievable" NSPS.   EPA believes that these decisions are distinguishable on numerous grounds, not least of which is that they predate substantial revisions to the CAA in 1990, including revisions to sections of the statute that pertain to emissions limitations such as section 302(k). At bottom, however, these prior cases stand for the more general principle that EPA should set standards that are achievable by appropriately designed, operated and maintained sources, and do not suggest that is required to set standards that exempt emissions during malfunctions.  As explained in detail in section X. A of the Preamble, nothing in section 111 or in case law requires EPA to consider malfunctions when determining what standards of performance reflect BSER and EPA does not consider it  appropriate to do so given the facts in this action.  EPA has promulgated standards that appropriately address variability for emissions from affected sources.  In addition, EPA is not finalizing the proposed 84-operating-month compliance period option because the final standard of performance for newly constructed sources is less stringent than the proposed standard so that a protracted compliance period to provide for variable performance is unnecessary, and because, as discussed in section V of the final preamble, EPA is identifying alternative compliance pathways for new steam generating EGUs that also would not need such an extended comment period to account for variable performance.  EPA specifically disagrees with commenters who argued that EPA has not provided an adequate explanation for why it has "departed from prior practice" and will not include "allowances" for emissions during malfunctions (i.e., exemptions like those previously provided in 40 CFR section 60.8(c)).  As EPA explained in the proposal, recent decisions of the D.C. Circuit have indicated that emission limitations under the CAA must impose continuous controls and cannot contain exemptions for emissions during malfunctions.  EPA explained the basis for its changed interpretation of the relevant statutory provisions in the proposal. EPA has authority to revise its prior interpretation of the CAA when further consideration indicates to EPA that its prior interpretation of the statute is incorrect.  (See, e.g., White Stallion Energy Center LLC v. EPA, 748 F.3d 1222, 1235 (D.C. Cir. 2014)).  See section X.A of the Preamble for additional response to these comments.
Multiple commenters (9382, 9425, 9734, 9666, and 10023) asked that malfunctions be excluded from compliance calculations.
Commenter 9425 asked that the EPA "exempt emissions associated with malfunctions from being factored into the compliance calculation."
Commenter 9382 and 9734 noted that "Section 60.8 of the NSPS regulations provides that unless specified otherwise in an applicable standard, excess emissions during SSM period shall not be considered a violation of the applicable emission limit." 
EPA disagrees with commenters who argued that emissions during malfunctions should be excluded from compliance calculations.  EPA acknowledges that 40 CFR section 60.8 provides that emissions during SSM events malfunctions shall not be considered a violation of the applicable emission limit, unless otherwise specified in the applicable standard.  As explained in the proposed action, however, EPA interprets the reasoning of the court in the D.C. Circuit's decision in Sierra Club v. EPA to apply to NSPS under section 111.  The commenters advocate that emissions during SSM events be excluded from compliance calculations and treated as exempt.  Such an approach is impermissible in light of the requirements of the CAA and the reasoning of the court in Sierra Club v. EPA concerning the statutory requirement for continuously applicable emission limitations.  See also section X.A of the final rule preamble for the EPA's response to these comments.
Multiple commenters (9512, 9666, and 10100) suggested that work practice standards should apply during periods of malfunctions instead of the otherwise applicable standard of performance.
Commenters 9512 and 9666 noted that EPA has authority under CAA section 111(h) to promulgate a "design, equipment, work practice, or operational standard" where it is not feasible to set or enforce a numerical emission limit.  
Commenter 9512 also referred to the "flexibility accorded by CAA section 302(k)" to "address emissions during malfunction events through operational requirements, rather than by applying the same limits on pollutant concentrations in exhaust gases that apply during normal operations." 
Commenter 10100 asked that the phrase, "[a]ll possible steps were taken to minimize the impact of the violation on ambient air quality, the environment and human health. . ." be excluded from the work standards.
EPA has authority under section 111(h)(1) to include a design, equipment, work practice, or operational standard, or a combination thereof, as part of a continuously applicable emission standard where that is appropriate and consistent with section 111(h)(2).  In this case, however, EPA has determined that it is not appropriate to create alternatives such as a work practice.  In particular, EPA has determined that no such treatment is appropriate in the case of emissions that result from malfunctions.  Even if the conditions of section 111(h)(2) were met, creation of a work practice for malfunctions presupposes that it is feasible to predict all possible forms of malfunctions and to devise a work practice that would adequately address emissions in a broad array of such events.  By definition, malfunctions are neither predictable nor routine.  By definition, they are sudden, infrequent, and not reasonably preventable failures of emissions control, process or monitoring equipment. Under these circumstances, EPA has concluded that excusing sources from the otherwise applicable emission standards during malfunctions is not the correct approach to imposing limits that will most effectively control emissions and provide incentive for compliance.  Instead, EPA has concluded that it is feasible to prescribe and enforce a standard of performance that applies at all times, including during malfunctions.  Given that compliance with the emission standard is determined on a 12-operating-month rolling average basis, the impact of periods of malfunctions on the total average over a 12-operating-month period is expected to be minimal. The 12-operating-month rolling average period provides sources the ability to accommodate intermittent periods of minor malfunctions and small spikes in emissions.  See section X.A for additional explanation for why EPA is not promulgating a work practice for emissions related to malfunctions.
Comment 13.2-8: Commenter 9512 stated that the EPA's explanation of the availability of the affirmative defense for violations due to excess emissions during malfunctions contradicted EPA's explanation of the burdens of the affirmative defense in connection with the Paperwork Reduction Act. The commenter asserted that "Either EPA has offered an unrealistically low accounting of the paperwork burden of the affirmative defense, or it has claimed that the affirmative defense supports the rationality of the proposed CO2 NSPS when, in fact, the Agency believes the affirmative defense will not play any role at all. Either way, the Proposed Rule does not contain a rational statement of the basis for EPA's proposed action, rendering the proposal an inadequate solicitation of public comment and in violation of the Paperwork Reduction Act."
EPA disagrees that its burden estimates for sources seeking to use the proposed affirmative defense were inconsistent with its proposed affirmative defense.  As explained in the proposal, EPA intended the affirmative defense to be available to sources only in appropriate circumstances that met the applicable requirements. EPA's interpretation of the CAA at the time of the proposal was that affirmative defense provisions were only consistent with statutory requirements if they were very narrowly drawn and limited to monetary penalties.   In any event, the commenter's concerns are irrelevant at this juncture because the EPA is not including a regulatory affirmative defense provision in the final rule. 
 Comment 13.2-9 Multiple commenters (8964, 8969, 8970, 8973, 8995, 9318, 9512, 9514, 9666, 9671, 9672, 9736, 10023, 10392, 10606, and 10876) stated that the proposed affirmative defense provisions are unlawful, indefensible, or contrary to section 111.
Multiple commenters (8964, 8969, 8970, 8973, 8995, 9318, 9671, 9672, 9736, 10392, and 10876) stated that the provisions place the burden of proof on the unit owner/operator and therefore "will only add to the hesitancy that utilities already have regarding their willingness to [build] new units (thus potentially threatening system reliability) at this time."
The EPA is not including a regulatory affirmative defense provision in the final rule. See section X.A of the final rule preamble for the EPA's response to this comment.
 Comment 13.2-10: Multiple commenters (9512, 9779, 10098, and 10554) asked that EPA include an affirmative defense provision for excess emissions during other modes of source operation..
Commenters (9512 and 10098) asked that an affirmative defense be available for excess emissions during startup and shutdown.
Commenter 10554 asked that the affirmative defense be expanded and that a new section be added that includes an affirmative defense against both "civil and criminal liability during an energy emergency as defined in CAA section 110(f) or when required to operate under an order of the Department of Energy (DOE) issued under the Federal Power Act (FPA) or when RTO may require the power for grid reliability reasons." 
Commenter 9779 asked that the EPA add grid emergency as event for which there is an affirmative defense.
The EPA is not including a regulatory affirmative defense provision in the final rule. See section X.A of the final rule preamble for the EPA's response to this comment.
 Comment 13.2-11: Commenter 7990 asked that the proposed affirmative defense be structured so that "an operator makes a prima facie demonstration that an unavoidable failure occurred, the burden of proof be shifted to EPA to show that the event was not a malfunction."
The EPA is not including a regulatory affirmative defense provision in the final rule. See section X.A of the final rule preamble for the EPA's response to this comment.
 Comment 13.2-12: Multiple commenters (9382, 9512, and 9734) stated that the requirements to satisfy the proposed affirmative defense provision are too stringent. 
Commenters 9382 and 9734 stated, "For instance, the rule could be interpreted as requiring sources to use off-shift and overtime labor to repair malfunctioning equipment in order to claim the defense. One of the conditions for the affirmative defense is that the affected source is operated in a manner consistent with good practices for minimizing emissions at all times. By definition, malfunctions are not easily foreseeable problems that can be planned for in advance. The NSPS regulations define a malfunction as 'any sudden, infrequent, and not reasonably preventable failure of air pollution control equipment, process equipment, or a process to operate in a normal or usual manner.' Because unforeseen malfunctions often result in excess emissions, this requirement should be removed."
Commenter 9512 noted that the affirmative defense is "unreasonable and impracticable." Commenter 9512 stated that "Proposed section 60.5530(a)(4) would preclude a facility from taking advantage of the affirmative defense if the malfunction involved bypassing control equipment or a process and the bypass was not 'unavoidable to prevent loss of life, personal injury, or severe property damage.' Commenter 9512 stated that it may be "difficult or impossible for a source to demonstrate that it met this criterion, even though bypassing the control equipment or the process was an appropriate exercise of good air pollution control practices."
Commenter 9512 offered the following example, "a bypass can constitute the best air pollution control practice in response to an upset in order to prevent excess emissions, e.g., to avoid fouling of pollution control equipment media that in turn would result in reduced pollution control equipment efficiency or increased pollution control equipment downtime. There can be substantial room for disagreement about what constitutes 'severe' property damage. Also, what degree of injury to employees must the bypass avoid in order to qualify as avoiding 'severe' personal injury? Besides the unclear and subjective nature of these criteria, there is nothing inherent to standards of performance under CAA section 111 that requires a source to avoid bypassing control equipment to such a degree. Lastly, it is not apparent at all why the CAA would disfavor bypassing 'a process'-as opposed to pollution control equipment-in this way."
The EPA is not including a regulatory affirmative defense provision in the final rule. See section X.A of the final rule preamble for the EPA's response to this comment.
 Comment 13.2-13: Commenter 9591 noted that the EPA only proposed the affirmative defense language under subpart TTTT and asked that the affirmative defense language be included under the GHG provisions as well.
The EPA is not including a regulatory affirmative defense provision in the final rule. See section X.A of the final rule preamble for the EPA's response to this comment.
 Comment 13.2-14:  Commenters stated that the proposed standards would violate the Constitutional rights of affected sources because sources remain liable for violations due to excess emissions during malfunctions and the proposal only provided a limited affirmative defense applicable to monetary penalties for such violations.  Commenters asserted that providing an affirmative defense was insufficient.  Commenters further noted that the legal validity of any such affirmative defense had been called into question by the decision of the D.C. Circuit in the NRDC v. EPA case.  
 Commenter 9666 stated that "the imposition of penalties for 'unavoidable' and, therefore innocent, conduct also would infringe on substantive due process principles under the Fifth Amendment" to the U.S. Constitution. 
Two commenters (9666 and 10023) stated that the proposed rule would violate the Eighth Amendment to the U.S. Constitution because it would impose liability for emissions they claimed are beyond the control of sources. Commenter 10023 stated that "Imposition of penalties for any conduct that is 'unavoidable' violates basic constitutional protections guaranteed by the Eighth Amendment and substantive due process.  Commenter 9666 asserted that even with an affirmative defense, the proposed standards would violate the "Excessive Fines Clause and the Cruel and Unusual Punishments Clause" by potentially subjecting a source to penalties for "unavoidable" conduct.  The commenter suggested that imposition of any penalties for violations due to "unavoidable" behavior per se "would not be proportional to the `offense' committed."
EPA notes that the commenters objected to the proposed rule on the grounds that it included only an affirmative defense to liability for violations due to emissions during malfunctions and they argued that was insufficient to shield sources from liability for such conduct.  As explained in section X.A of the Preamble, EPA is not including an affirmative defense provision in the final rule. Even without an affirmative defense provision, however, EPA does not agree with the premise of the commenters that the CAA requires EPA to provide sources with exemptions from liability for emissions during malfunctions or alternatively requires EPA to set emission limitations at levels that functionally exonerate all emissions during malfunctions in order to meet Constitutional requirements.  As the commenters acknowledged, the court's decision in Sierra Club v. EPA forecloses exemptions for emissions during malfunctions (or in their view, "calls into question" the legality of any such exemptions). EPA interprets section 111 to require continuous emissions limitations with no exemptions for emissions during any mode of source operation, including during malfunctions.  Section 111 also does not require EPA to set standards that account for emissions during malfunctions.  Accordingly, EPA is establishing standards that sources must meet on a continuous basis.  As explained in Section X.A of the Preamble, EPA believes that the enforcement structure of the CAA already addresses the concerns of the commenters.  EPA and other parties can exercise enforcement discretion in the event of violations due to malfunctions. Sources retain the ability to raise any appropriate legal or equitable defenses in the event of an enforcement action. Courts have discretion to determine whether the conduct at issue should result in liability and, if so, the appropriate amount of penalty for a violation.  The commenter's arguments appear to be that any penalty assessed for a violation of an NSPS due to a malfunction would per se be excessive or constitute cruel and unusual punishment.  The thrust of these comments suggests that the existing CAA enforcement provisions are facially unconstitutional.  EPA disagrees.  The CAA does not mandate that a penalty is automatically assessed for a violation.  Rather, the CAA establishes a maximum civil penalty in section 113(b) but then expressly provides in section 113(e) the criteria that EPA or the courts (as appropriate in administrative or judicial enforcement) "shall take into consideration (in addition to such other factors as justice may require)."  These criteria explicitly include consideration of "good faith efforts to comply." Thus, the CAA on its face does not mandate the imposition of any penalty automatically, much less one that is per se excessive.  To the contrary, EPA believes that the existing provisions of the CAA assure due process consistent with the requirements of the 5[th] Amendment and preclude "excessive" or "cruel and unusual" penalties consistent with the 8[th] Amendment.  In the event that a source feels that the penalties rise to such a level, they have the ability to appeal the penalties as has occurred in notable cases such as State Farm Mut. Auto Ins. Co v. Campbell (See, 538 U.S. 408 (2003)). Finally, EPA notes that this view of the enforcement provisions of the CAA is consistent with that expressed by the DC Circuit in the NRDC v. EPA decision, in which the court noted that the absence of an affirmative defense provision for violations due to malfunctions does not preclude sources from raising comparable facts and arguments in the context of an enforcement action, consistent with the provisions of sections 113 and 304.
Startup and Shutdown
13.1 
Commenter 10619 agreed that emissions during startup and shutdown are negligible, "particularly averaged over a rolling 12-operating month period."
The EPA agrees and acknowledges the commenter's support.
Commenter 10392 noted that the EPA "fails to recognize the fact that unit operation is not always within the control of unit owners/operators due to the nature of today's competitive electricity markets, including operations in response to RTO-declared emergency situations."
Given that the duration of startup or shutdown periods is expected to be small relative to the duration of normal operation and that the fraction of power generated during periods of startup or shutdown is expected to be very small, the impact of periods of startup and shutdown on the total average over a 12-operating-month period is expected to be minimal. A new fossil fuel-fired steam generating EGU  -  if constructed  -  would, mostly likely, be built to serve base load power demand and would not be expected to routinely start-up or shutdown or ramp its capacity factor in order to follow load demand. Thus planned start-up and shutdown events would only be expected to occur a few times during the course of a 12-operating-month compliance period.  Moreover, compliance on a 12-operating-month rolling average period basis provides sources the ability to accommodate startup and shutdown instances such as those pointed out by the commenter. 
Multiple commenters (8944, 8952, 9423, 9425, 9665, 9777, 9779, 10242, 10554, 10606, and 10965) recommended that emissions during startup and shutdown be exempted from the standards in the rule.
Commenters 8944 and 8952 asked that the EPA exempt startup/shutdown and load operation below 50% of nameplate rated output or Original Equipment Manufacturer (OEM) rated output.
Commenters 8944 and 8952 stated that an exemption from startup and shutdown will "support a rapidly growing installed base of non-dispatchable renewable generation."
Commenter 9423 asked that the EPA "withdraw or delay the adoption of the rule until an appropriate standard or method for evaluating compliance during SSRL [startup, shutdown, and reduced load] operation has been provided." 
Commenter 9425 noted that combustion turbines operate "essentially as a simple cycle machine" during startup and thus these periods should be exempt.
Commenter 9665 asked for an exemption from startup and shutdowns and also for part load operation below 75 percent of OEM rated output. 
Commenter 9777 noted "EPA lacks sufficient data and understanding of how full-scale CCS units function to assess operations during startup and shut down."
Commenter 10242 noted that "the proposed standard for CO2 is in terms of lb/MWh which is not truly an appropriate metric during startup and shutdown."
 It is legally impermissible not to have some standard for startup and shutdown conditions.  See preamble section X.A and Sierra Club v. EPA, 551 F.3d 1019 (D.C. Cir. 2008) (under section 302(k) of the CAA, emissions standards or limitations must be continuous in nature and that the SSM exemption violates the CAA's requirement that some CAA section 112 standards apply continuously)  Furthermore, separate startup  and shutdown standards are inappropriate for coal-fired fossil fuel-fired units for the reasons stated in comment 13.3.2 above.
Commenter 10606 asked that the EPA "establish an optional, alternate CO2 standard that is based on heat input" during startup and shutdown events.
 See response 13.3-2 above.
Multiple commenters (8964, 8969, 8970, 8995, 9194, 9318, 9396, 9425, 9512, 9665, 9671, 9672, 9736, 9779, 9780, 10100, 10392, 10500, 10554, 10618, and 10876) asked that the EPA allow for work practice standards to minimize emissions during startup and shutdown periods.
Commenters 9425 and 9779 noted unintended consequences if the rule does not allow for work practices during startup and shutdown periods. 
Commenters 9425, 9779, and 9780 gave the following example, If an NGCC unit is requested by an Independent System Operator to run on an intermittent basis with frequent startup and shutdowns, or even at low capacity factors, causing CO2 emissions to be high, it would put the unit at risk of not being in compliance with the NSPS. Rather than risk noncompliance, a utility would be likely to "withhold a unit from the market, or only offer it into the market at times when the unit could be dispatched at high loads." Commenter 9425 and 9779 noted that such practices could distort electricity markets and increase consumer costs.
Commenter 9512 stated, "EPA cannot, consistent with CAA sections 111 and 302(k), simply ignore the possibility of using some type of work practice, etc. standard during SSM events."
Commenter 9512 noted that Section 111(h)(2) allows EPA to determine that it is "'not feasible to prescribe or enforce a standard of performance' because it is not feasible to capture the pollutant and emit it through a particular conveyance, or because it is not practicable to measure emissions 'due to technological and economic limitations.'"  
See response 13.3-2 above explaining why no separate startup and shutdown standard is necessary.  In addition, commenters failed to explain their theory as to why a work practice would comply with section 111 (h)(2). The EPA knows of no credible basis for finding that is not economically or technically practicable to measure emissions during startup and shutdown, and it certainly is feasible to capture and measure CO2 emitted during startup and shutdown.
Multiple commenters (8973, 9512, 9665, and 10100) dispute the assumption that CO2 emissions during partial load are consistent with CO2 emissions during startup and shutdown.
Commenter 9665 noted that this assumption is flawed because "periods of startup and shutdown are demonstrably different from partial load periods. Partial load operation is limited to levels that achieve emission compliance for all criteria pollutants, including NOx and carbon monoxide (CO). When operating at part load, the plant equipment, including emission control equipment, is thermally soaked at operating temperature and combustion is within a stable steady state regime capable of maintaining rated emission performance. Start-up events, however, begin from a stand still, no load condition and include operation at loads below the emission compliant level. Further, the equipment is experience rapid temperature changes which induce additional transient factors contributing to the variability of start emissions while inducing thermal stresses and thermal soaking requirements to achieve full operating conditions."
See sections V.J.1 and X.A. of the preamble.
Multiple commenters (7990, 8957, 9425, and 9512, and 10105) noted that the calculation of the standard must include emissions during startup and shutdown if startup and shutdown are not exempted from the standard. Commenters agreed that these emissions were understated in the EPA's analyses. Commenter 9512 recommended deferring promulgation until such data are obtained.
Commenter 8957 recommended that the EPA use a calculated value for the electrical load instead of dividing by zero during startup and shutdown events. Commenter 8957 stated, "a possible approach that EPA could use is to assume 100% of the useful thermal energy generated at startup and shutdown is converted into an electrical load value of MWh until the end of startup and shutdown."
Commenter 9425 stated, "failing to account for lower utilization rates and more frequent SS periods punishes NGCC units for the flexibility for which they are regularly designed and built. EPA should increase the proposed NSPS standard for new units to accommodate actual usage and emissions data from the full range of NGCC unit operations." 
Commenter 9512 noted several reasons why emissions data from startup and shutdown are not readily available:
   oo performance testing during SS are not allowed
   oo concentrations during SS may exceed the span of the monitor
   oo monitoring system QA/QC parameters may not be met during SS
Commenter 9512 recommended analyzing CO2 CEMS data specific to startup and shutdown events form multiple facilities and also study operational logs to ensure that the averaging period is sufficiently long so that typical startups and shutdowns would not cause the unit to be out of compliance.
Commenter 10105 noted that the proposed rule could deter renewable generation due to the increased number of startups and shutdowns inherent in accommodating renewable generation sources. 
 See sections V.J.1 and X.A. of the preamble.
