### Summary of EGU NSPS Pu blic Comments and Responses on Amendments Proposed November 30, 2012 (77 FR 71323)

U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Sector Policies and Programs Division Research Triangle Park, North Carolina 27711

March 2013The primary contact regarding questions or comments on this document is:

Christian Fellner U.S. Environmental Protection Agency Energy Strategies Group (D243-01) Research Triangle Park, North Carolina 27711

Email: fellner.christian@epa.govi 

### Table of Contents

LIST OF COMMENTERS ............................................................................................................ . 1

1.0 NATURAL GAS DEFINITION .......................................................................................... 2

2.0 IGCC DEFINITION ............................................................................................................ 3

2.1 Definition Similar to the Definition in the MATS ........................................................... 3

2.2 Alternative NSPS IGCC definition with changes ............................................................ 3

3.0 FILTERABLE PM EMISSIONS ......................................................................................... 5

3.1 Measuring and Averaging Changes ................................................................................. 5

3.2 Opacity Monitoring .......................................................................................................... 6

4.0 TECHNICAL CORRECTIONS .......................................................................................... 8

5.0 COMMENTS ON TOPICS NOT PROPOSED FOR RECONSIDERATION ................... 9

5.1 NO X and SO 2 Emission Rates and Compliance ............................................................... 9

5.2 Use of a Digital Opacity Compliance System .................................................................. 9

6.0 GENERAL COMMENTS ................................................................................................. 10

7.0 INCORPORATION BY REFERENCE ............................................................................ 111 LIST OF COMMENTERS

Commenter Name Commenter Organization EPA Docket ID
Steve Jenkins CH2M Hill Engineer s, Inc. EPA-HQ-OAR-2011-0044-5781

Mark Sokolow Law Office of Ma rk Sokolow EPA-HQ-OAR-2011-0044-5790

Claire M. Olson Basin Electric Po wer Cooperative EPA-HQ-OAR-2011-0044-5791

Lee B. Zeugin Hunton & Williams LLP et al. on behalf of Utility Air Regulatory Group (UARG) EPA-HQ-OAR-2011-0044-5794

Myra Glover Entergy Services, Inc. EPA-HQ-OAR-2011-0044-5796 Greg F. Myers Consumers Energy EPA-HQ-OAR-2011-0044-5798 Paul M. Ling Kansas City Power & Li ght Co. (KCPL) EPA-HQ-OAR-2011-0044-5801

Kenneth J. Anderson Ameren Co rporation EPA-HQ-OAR-2011-0044-5805 J. Michael Geers Duke Energy et al. EPA-HQ-OAR-2011-0044-5806 Norman Shilling General Electric Co. (GE) EPA-HQ-OAR-2011-0044-5813 Raymond L. Evans FirstEnergy Corpor ation (FE) EPA-HQ-OAR-2011-0044-5814 Eli Brill Waste Management (WM) EPA-HQ-OAR-2011-0044-5818

Claire M. Olson Basin Electric Powe r Cooperative EPA-HQ-OAR-2009-0234-20247

Debra J. Jezouit Baker Botts L.L.P. et al. on behalf of The Class of ‘85 Regulatory Response Group EPA-HQ-OAR-2009-0234-20269

Myra Glover Entergy Services, Inc. EPA-HQ-OAR-2009-0234-202792 1.0 NATURAL GAS DEFINITION

Comment: Commenter (5791) noted that th eir subsidiary owns and opera tes a commercial-scale coal gasification plant that manufactures synthetic natural gas from lignite. The commenter stated that the synthetic natural gas produced at the commenter’s plant chemically sa tisfies the definition of “natural gas” contained in the first sentence of the reconsideration, but the phras e “coal-derived gas” in the last sentence of the new definition makes synthetic na tural gas fall out of the definition. The commenter recommended that the natural gas definition should reflect chemical compositi on, rather than point of origin. The commenter recommended the following language:

Natural gas means a fluid mixture of hydrocar bons (e.g., methane, ethane, or propane), composed of at least 70 percent methane by volume or that has a gross calorific value between 35 and 41 megajoules (MJ) per dry standard cubic meter (950 and 1,100 Btu per dry standard cubic foot), that maintains a gaseous state under ISO conditions. In addition, natural gas contains 20.0 grains or less of total sulfur per 100 standard cubic feet. Finally, natural gas does not include the following gaseous fuels: landfill gas, digester gas, refinery gas, sour gas, blast furnace gas, coal -derived gas (except for synthetic natural gas that meets pipeline standards or the definition in 40 CFR § 63.7575. Subpart DDDDD)

, producer gas, coke oven gas, or any gaseous fuel produced in a process which might result in highly variable sulf ur content or heating value.

Response: The EPA has concluded that the suggeste d change is unnecessary. The amendments

discussed below have the same effect as the one s uggested by the commenter and coal-derived synthetic natural gas will be treated the same as natural gas. Even though the amended definition of natural gas excludes coal-derived synthetic na tural gas, paragraph 60.42Da(b)(2) has been amended to include “and/or synthetic gas that chemically meets the de finition of natural gas.” This paragraph exempts facilities burning coal-derived synt hetic natural gas from the opacity standard. In addition, paragraph 60.49Da(a)(4) has been amended by changing “natural ga s” to “gaseous fuel” so that coal-derived synthetic natural gas-fired facilities have the same SO 2 monitoring options as natu ral gas-fired facilities.

Comment: Commenter (20247) stated that the exclusion of coal-derived gas from the definition of natural gas (40 CFR 61.41Da) may create ambiguity when compared to the change that includes synthetic natural gas as an accepta ble startup fuel. The Commenter s uggested the following change in the definition of natural gas:

“Natural gas means . . . coal-derived gas (e xcept for synthetic na tural gas that meets pipeline standards or the defi nition in 40 CFR §63.7575, Subpart DDDDD ), . . .

Response: This comment addresses an issue related to startup and shutdown. As the EPA is not taking final action on requirements applicab le during periods of startup and shutdown at this time we are not responding to this comment.

Comment: Commenter (5818) agreed with the proposed definition of natural gas. The commenter supported the proposed definition that clarifies that landfill gas is am ong the specific gaseous fuels that do not qualify as natural gas under Subpart Da, and thus , is not a fossil fuel as defined under Subpart Da and other air pollution regulations governing the combustion of fossil fuels, such as EPA’s MATS.

Response: No response necessary.3 2.0 IGCC DEFINITION

2.1 Definition Similar to the Definition in the MATS

Comment: Commenter (5813) noted that wh ile either of the IGCC defin itions effectively address the issue of IGCC facilities switching ap plicability between the stationary combustion turbine NSPS and the Utility NSPS, they prefer the alte rnate definition. The commenter stated the alternate definition provides classification certainty throughout the life of the IGCC plant and also allows more flexibility as any

solid-based fuel can be used. The commenter further st ated that it is unlikely that a combined cycle

would be modified to burn solid-derived fuel due to the technical difficulty, cost and outage requirements. The commenter stated that it may be ch allenging for IGCC units fi ring natural gas to meet Subpart KKKK requirements. The comment er stated that projects that initially inst all natural gas

turbines with the intent to later convert to syngas would need to be permitted as natural gas units (under subpart KKKK).

Response: No response necessary since the altern ate IGCC definition has been finalized.

Comment: Commenters (5781, 5794, 5806) not ed that the regulatory la nguage in proposed §60.41Da (Definitions) has inadvertently inserted the wo rd “natural” between “synthetic” and “gas.” Commenter (5813) stated that the proposed IGCC defi nition could cause syngas to be confused with synthetic natural gas that could leadto unintentional requirements to meet lower limits for natural gasfired plants. The commenter suggested these changes:

“Integrated gasification combined cycle el ectric utility steam ge nerating unit or IGCC electric utility steam generating unit means an electric utility combin ed cycle gas turbine that burns a synthetic natural gas (syngas ) derived from coal and/or solid oil-derived fuel for more than 10.0 percent of the average annual heat input during any 3 consecutive calendar years or for more than 15.0 percent of the annual heat input during any one calendar year in a combined cycle gas turbine. No solid coal or solid oil-derived fuel is directly burned in the unit during operation.”

Response: No response necessary since the alternate IGCC definition has been finalized. IGCC facilities burning synthetic gas will be subject to the re quirements in subpart Da and not subpart KKKK.

2.2 Alternative NSPS IGCC definition with changes

Comment: Commenters (5794, 5806) supporte d the alternate definition for IGCC electric utility steam generating units, including the phr ase “startup and commissioning, s hutdown,” as Commenter (5794) suggested in response to the 2011 proposed rule. Comm enter (5794) stated that their preferred definition concerns design rather than operatio n, which is the appropriate focus.

Commenter (5813) preferred the alternative definiti on modified from the NSPS definition of IGCC. The commenter stated that the modified definition provides certainty as to classification as a solid fuel plant and fuel flexibility.

Response: The alternate IGCC definition has been fi nalized as suggested by the commenters.4 Comment: Commenter (5813) stated that having differe nt definitions applying to IGCC in the MATS and NSPS rules is a confusing and unnecessary inc onsistency, and that EPA should consider changing

the MATS definition to that in the NSPS.

Response: We have concluded that the alternative definiti on is most appropriate and are adopting the definition which is consistent with the Agency’s st atements on IGCC contained in the RTC in support of the final Utility NSPS rule published on Februa ry 16, 2012 (77 FR 9304). The Utility NSPS IGCC definition deals with the intent of an IGCC facility a nd is, thus, broader than th e definition in the MATS NESHAP. The facility would still be subject to the same criteria pollutant emi ssion standards even when burning natural gas for extended peri ods of time. The MATS NESHAP ap plicability is determined based

on the EGU’s utilization of coal a nd oil and the rule may not apply de pending on the extent of natural

gas usage.

Comment: Commenter (5813) stated that the uncertainty of the Administrator’s discretion in the NSPS definition (“may waive”) is of concern. The comm enter recommended that the EPA change the word “may” to “shall” in the alternative definition (2) so there is not an indeterminate regulatory application or interpretation that subjects an IGCC unit to dual regulatory requirements during its operational life.

Response : The EPA has concluded that “may waive” is an appropriate use of the Administrator’s discretion. Every situation is site sp ecific, and the burden is on the owne r/operator to present the case for why the combustion of nonsolid-deriv ed fuels is within the intent of the design of the facility.5 3.0 FILTERABLE PM EMISSIONS

3.1 Measuring and Averaging Changes

Comment: Commenter (5794) agreed that Subpart Da and Subpart UUUUU should use the same calculation and monitoring procedures for new unit emission rate calcu lation procedures and monitoring options for filterable PM.

Commenter (5794) stated that Subpart Da and Su bpart UUUUU should have the same option for use of quarterly stack tests.

Response: With respect to this issue, the same ra tionale applies to both the NSPS and NESHAP. Therefore, the finalized calculations and monitoring procedures for PM are the same for the NESHAP and NSPS and the quarterly stack te sting option has been removed. EGUs complying with an outputbased emissions standard can be designed to inco rporate PM CEMS or PM CPMS from the outset, without being impeded by retrofit location installation constraints that would impact existing EGUs.

Continuous direct measurement of e ither filterable PM or a correla ted parameter are preferable to quarterly stack testing for determining compliance on a continuous basis, Therefore, this final action requires EGUs complying with an output-based standard to use ei ther PM CEMS or PM CPMS as options for determining compliance with the PM limits.

Comment: Commenter (5794) supported the EPA’s revision of the rule to allow facilities constructed, reconstructed, or modified after May 3, 2011 the a lternative of complying using the PM CPMS or quarterly stack testing options. The commenter stated that the EPA cannot require Subpart Da sources to use a compliance method – PM CEMS – that has not b een demonstrated to be feasible or accurate for that purpose. The commenter stated that to require use of PM CEMS, EPA must evaluate data from PM CEMS in the standard setting process, and estab lish the achievability of the required PS 11 correlation criteria at the level of the appl icable standard. The commenter reco mmended that if the EPA does not finalize the language allowing use of the PM CPMS and quarterly stack testing procedures as specified in Subpart UUUUU, EPA should add thos e options directly to Subpart Da.

Response: The EPA disagrees with the commenters sugge stions regarding limits on its ability to prescribe compliance determination methods. PM CE MS continue to be in stalled and operated at existing EGUs; moreover, their use has been required and successfully used at EGUs that have emission

rates at levels near those containe d in the standards. Ther efore, PM CEMS remain an option to monitor emissions of PM. However, the final rule also al lows the use of PM CPMS . Owners/operators that believe the use of PM CEMS is not the best appro ach for their EGUs may elec t to use a PM CPMS. The EPA has concluded that either option provides adequa te assurance of complian ce with the PM standard. As described above, the EPA has concluded that the us e of quarterly testing is not appropriate for new electric utility steam generating units.

Comment: Commenter (5794) discussed a nd objected to the phrase “appl icable 30-boiler operating day rolling average PM emissions limit” in §60.48Da(f) becau se no other provision in subpart Da states that a 30-operating day rolling average applies to any standard in §60.42D a. The commenter recommends that the EPA also remove the reference in this pr ovision to modified units. The commenter noted that under this proposal, units m odified after May 3, 2011 would be subj ect to the PM emissions limit in §60.42Da(c) or (d) and the compliance procedures in §60.48Da(o) or (p), not the procedure in §60.49Da(f). [Proposed §§60.42Da(e)(1)(ii) and 60.48Da( o), 77 Fed. Reg. at 71335-36.] The commenter6 stated that Section §60.48Da(p), which allows us e of PM CEMS in lieu of the procedures in §60.48Da(o), specifies use of a “24-hour daily (block) av erage” for those modified units that opt to use PM CEMS to demonstrate compliance. [40 CFR §60.48Da(p)(4).]

To address the above issues, the commenter s uggested the following rewording of 60.48Da(f):

....For affected facilities for which construction, modification, or reconstruction commenced after May 3, 2011 that opt unde r §60.49Da(t) to demonstrate compliance using PM CEMS , compliance with the applicable 30

- boiler operating day rolling average PM emissions limit in §60.42Da(e)(1)(i) is determined on a 30-boiler operating day rolling average basis by calculating the arithmetic av erage of all hourly PM emission rates for the 30 successive boiler operating da ys, except for data obtained during periods of startup or shutdown.

Response: The regulatory text has been revised to remove “modification” and move “30 boiler operating day rolling average” as suggested by the commenter. However, the paragraph references have been left more general to facili tate potential future amendments without having to revise specific paragraph references.

Comment: Commenter (5794) agreed with the proposed rem oval of the reference to a daily average in relation to units constructed, recons tructed, or modified after May 3, 2011 and with the use of a straight arithmetic average of the hourly PM emission rate s for the 30 successive boiler operating days. The commenter stated that this compliance methodology is the same as the one used in Subpart UUUUU and, as long as periods of start up and shutdown are excluded from th e compliance calculation, it is not necessary to sum all of the hourly output values prior to determini ng a numerical value in order to compensate for the lack of output. The commenter agreed that compliance for the new unit filterable PM

limit should be calculated the same way under both rules.

Response: No response necessary.

Comment: Commenter (5794) agreed with the revisions to the introductory text of §60.48Da(o) to add a reference to the standard in §60.42D a(e)(1)(ii) and to revise the in troductory text of §60.48Da(o)(1), (o)(2), (o)(3), (o)(3)(i), and (o)(4) to remove re ferences specific to standards and facilities. The

commenter assumed the intended effect of the re visions is to make these compliance provisions applicable to any facility constructed, reconstr ucted, or modified after February 28, 2005 that is demonstrating compliance with an input-based sta ndard through performance te sting rather than PM CEMS. If that is EPA’s intent, the commenter expressed agreement with these revisions.

Response: The intent was to make the provisions more broadly applicable and as such no response is

necessary.

3.2 Opacity Monitoring

Comment: Commenters (5796, 20269, 20279) su pported the proposed clarific ation that EGUs using a PM CPMS to monitor PM emissions are exempt from the requirement to install a COMS.

Commenter (5794) stated that in the Reconsid eration proposal, the exem ption from the COMS requirement for any facility that operates a PM CP MS according to the requirements in Part 63, subpart7 UUUUU is moved from §60.49Da(a)(4) to §60.49Da(a)(2), and as a re sult, imposes new monitoring on these units without any jus tification. The commenter stated that th e change is not a clarification, but a significant revision, and the commenter objected to the revision. The commen ter stated that if a facility is demonstrating continuous compliance with the applicable PM limit using a PM CPMS, there is no basis for requiring monitoring of the surrogate opac ity standard. The commenter stated that the EPA must issue a proposal explaining why such additi onal monitoring is necessary, and submit a proposed information collection request ju stifying the additional testing unde r the Paperwork Reduction Act.

Response: While PM CPMS do not provide a measured emi ssions rate, the EPA has concluded that the continuous direct measurement of a correlated para meter and indication whethe r the operating parameter has been exceeded provides similar assurance as PM CEMS that a facility is continuously operating below a specified emissions rate. In previous rulemakings, the EPA determined that the 20% opacity standard was unnecessary for subpart Da facilities us ing PM CEMS to demonstrate compliance with an

emissions limit of 0.03 lb/MMBtu or lower. At this emissions rate, a facility will emit opacity on the lower end of an opacity monitor cap ability, and increases in PM emissi ons might only mildly deflect the opacity monitor output. However, a PM CPMS is cons iderably more sensitive than an opacity monitor at detecting fluctuations in PM level. Therefore, a small increase in PM emissions at low PM concentrations is more easily detected using PM CP MS and has a clear advantage compared to opacity monitoring systems. Consequently, the use of PM CP MS together with compliance with the subpart Da PM emissions rate of 0.03 lb/MMBtu provides sufficien t assurance that the facility is operating with an opacity of less than 20 percent. Th erefore, the paragraph is not be ing moved, and facilities using PM CPMS are not required to monitor opac ity and the rule burden is unchanged.8 4.0 TECHNICAL CORRECTIONS

Comment: Commenter (5794) agreed with the revision of the subpart Da filterable PM standard applicable to facilities for which construction, reconstructi on, or modification commenced before March 1, 2005 to 13 ng/J (0.03 lb/MMBtu) h eat input. The commenter cite d their NSPS Reconsideration Petition and NSPS Petitioners’ Brief in support of the revision. The commenter noted that EPA’s

revision of the standard to incl ude an additional significant digit was unlawful. The commenter saw no

reason to solicit comment on this change, and stated that the EPA lacks discretion under the CAA to do anything other than reinstate the original limit as of April 16, 2012.

Response: The change was necessitated by an inadvertent error and the language has been finalized as proposed.

Comment: Commenter (5794) agreed with the revision of the regulator y text to specify that the requirements in 40 CFR 60.42Da(c) or (d), which includes two additional alternative limits, are applicable to facilities modified after February 28, 2005. The commente r stated that the revision is consistent with the Agency’s determination of the be st demonstrated technology for such modified units and with the Agency’s stated intent in the final ru le. The commenter stated that to finalize any other standard, EPA would have to issue a new proposal justifying the new standa rd. The commenter cited

their NSPS Reconsideration Petiti on and NSPS Petitioners’ Brief in support of the revision.

Response: The language has been finalized as proposed.

Comment: Commenter (5794) stated no objec tions to removal of the phrase “at all times except during periods of startup and shutdown” in the introducto ry text of §60.42Da(e)(1), provided that the EPA retains the language in §60.48Da(a).

Response: The removal of the phrase has been fi nalized as proposed and the language in § 60.48Da(a) is unchanged.

Comment: Commenter (5813) stated that the phrase in §60. 42Da(e)(1) is in error and should be

corrected as follows:

“...the owner or operator shall not cause to be discharged into the atmosphere from that affected facility any gases that contain PM in excess of the applicable emissions limit...”

Response: Paragraph 60.42Da(e) has been revised to incl ude “not” as suggested by the commenter. In addition, “... any gases that contain PM in excess of ...” in paragraphs (e)(1)(i) and (ii) is redundant since the phrasing is already c ontained in paragraph (e)(1) and therefore has been deleted.9 5.0 COMMENTS ON TOPICS NOT PR OPOSED FOR RECONSIDERATION

5.1 NO X and SO 2 Emission Rates and Compliance

Comment: Commenter (5813) stated that for new facilit ies, demonstration of compliance with the NO X standard as defined in §60.44D a is not consistent with that of the alternative NO X +CO limit defined in §60.45Da. The commenter stated that in §60.45Da NO X +CO is determined on a 30-boiler operating day rolling average basis, but for NO X , §60.44Da excludes the clarification of a 30-day average basis. The

commenter discussed IGCC natu ral gas startup, and how NO X emissions are higher during that time than during operation with syngas. The co mmenter stated that in the ab sence of the 30 day provision, the

NO X -only requirement could be interpreted as an absolute and instantaneous limit. The commenter suggested that flexibility to average emissions is needed to compensate for intermittent higher NO X emissions that occur during plant startup for IGCC plants, and that a 30-day rolling average for NO X compliance be added to §60.44Da to avoid potential misinterpretation and misapplication of the

standard.

Response: The EPA has concluded that the current languag e is sufficiently clear. Paragraph 60.48Da(b) in the compliance provisions secti on specifies that the averaging pe riod is 30 boiler operating days. Stating the “30-boiler operating day average” averaging period in the NO X +CO section is redundant and could be removed without changing the rule requirements..

5.2 Use of a Digital Opacity Compliance System

Comment: Commenter (5794) referred to the provision promulga ted as §60.49Da(a)(3)(iv) but incorrectly codified in th e electronic CFR as §60.49Da( a)(4)(iv), regarding the opt ion for use of a digital opacity monitoring system. The commenter noted that in 2009, the commenter judi cially challenged this provision and petitioned for administra tive reconsideration of it. The commenter stated that because the purpose of this republication is simp ly to correct the codification error and that the Agency is not accepting comment in this proceeding on the substance of these provisions, the commenter incorporated their prior objections, but did not reiterate their objections in this comment letter. However, the commenter requested that the EPA co nfirm in response to comments that if EPA finalizes this proposed error correction, the commenter need not judicially ch allenge the final rule in order to preserve its objections.

Response: The amendment is only intended to correct the codification error and not as a substantive change that the EPA intended to request comment on.10 6.0 GENERAL COMMENTS

Comment: Commenter (5790) stated that the air emission standards should be enforced in adjacent countries in order to give industr y a level playing field. The commente r stated that the emission limits

should be tied to viable health standards that can be documented.

Response: This issue is outside the scope of this rulemaking. It is beyond the legal authority of a Clean Air Act section 111 rulemaking to enforce emission stan dards in other countries. As to the commenter’s second comment, under the existing Clean Air Ac t, section 111 standards are technology-based standards, not health-based standards.11 7.0 INCORPORATION BY REFERENCE

Comment: Commenters (5798, 5801, 5805, 5806, 5814) suppor ted the comments of UARG (EPA-HQOAR-2011-0044-5794).

Comment: Commenter (5794) incorporat ed by reference the portions of its NSPS petitions for

reconsideration that address i ssues covered by the proposed rec onsideration rule (EPA-HQ-OAR-2011- 0044-5771).