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Daily Rules, Proposed Rules, and Notices of the Federal Government

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2011-0851, FRL 9719-9]

Approval and Promulgation of Implementation Plans; State of Montana; State Implementation Plan and Regional Haze Federal Implementation Plan

AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
SUMMARY: The Environmental Protection Agency (EPA) is promulgating a Federal Implementation Plan (FIP) to address regional haze in the State of Montana. EPA developed this FIP in response to the State's decision in 2006 to not submit a regional haze State Implementation Plan (SIP) revision. The FIP satisfies requirements of the Clean Air Act (CAA or "the Act") that require states, or EPA in promulgating a FIP, to assure reasonable progress towards the national goal of preventing any future and remedying any existing man-made impairment of visibility in mandatory Class I areas. In addition, EPA is approving one of the revisions to the Montana SIP submitted by the State of Montana through the Montana Department of Environmental Quality on February 17, 2012, specifically, the revision to the Montana Visibility Plan that includes amendments to the "Smoke Management" section, which adds a reference to Best Available Control Technology (BACT) as the visibility control measure for open burning as currently administered through the State's air quality permit program. This change was made to meet the requirements of the Regional Haze Rule. EPA will act on the remaining February 17, 2012 revisions in the State's submittal in a future action.
DATES: This final rule is effective October 18, 2012.
ADDRESSES: EPA has established a docket for this action under Docket ID No. EPA-R08-OAR-2011-0851. All documents in the docket are listed on thewww.regulations.govWeb site. Although listed in the index, some information is not publicly available, e.g., Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are available either electronically throughwww.regulations.gov,or in hard copy at the Air Program, Environmental Protection Agency (EPA), Region 8, 1595 Wynkoop Street, Denver, Colorado 80202-1129. EPA requests that if at all possible, you contact the individual listed in theFOR FURTHER INFORMATION CONTACTsection to view the hard copy of the docket. You may view the hard copy of the docket Monday through Friday, 8 a.m. to 4 p.m., excluding Federal holidays.
FOR FURTHER INFORMATION CONTACT: Scott Jackson, Air Program, Mailcode 8P-AR, Environmental Protection Agency, Region 8, 1595 Wynkoop Street, Denver, Colorado 80202-1129, (303) 312-6107, orJackson.Scott@epa.gov.
SUPPLEMENTARY INFORMATION:

Definitions

For the purpose of this document, we are giving meaning to certain words or initials as follows:

• The words or initialsActorCAAmean or refer to the Clean Air Act, unless the context indicates otherwise.

• The initialsA/Fmean or refer to air-to-fuel.

• The initialsALMmean or refer to Ammonia Limiting Method

• The initialsARMmean or refer to Administrative Rule of Montana.

• The initialsARPmean or refer to the acid rain program.

• The initialsARSmean or refer to Air Resources Specialists.

• The initialsASOFAmean or refer to advanced separated overfire air.

• The initialsBACTmean or refer to Best Available Control Technology.

• The initialsBARTmean or refer to Best Available Retrofit Technology.

• The initialsCAAmean or refer to the Clean Air Act.

• The initialsCAMmean or refer to compliance assurance monitoring.

• The initialsCAMDmean or refer to EPA Clean Air Markets Division.

• The initialsCAMxmean or refer to Comprehensive Air Quality Model.

• The initialsCBImean or refer to confidential business information.

• The initialsCCMmean or refer to EPA Control Cost Manual.

• The initialsCCOFAmean or refer to close-coupled overfire air system.

• The initialsCDSmean or refer to circulating dry scrubber.

• The initialsCGAmean or refer to gas cylinder audit.

• The initialsCELPmean or refer to Colstrip Energy Limited Partnership.

• The initialsCEMSmean or refer to continuous emissions monitoring systems.

• The initialsCEPCImean or refer to Chemical Engineering Plant Cost Index.

• The initialsCFACmean or refer to Columbia Falls Aluminum Company.

• The initialsCFBmean or refer to circulating fluidized bed.

• The initialsCKDmean or refer to cement kiln dust.

• The initialsCMAQmean or refer to Community Multi-Scale Air Quality modeling system.

• The initialsCPMSmean or refer to continuous parametric monitoring system.

• The initialsCOmean or refer to carbon monoxide.

• The initialsCPImean or refer to Consumer Price Index.

• The initialsCRFmean or refer to Capital Recovery Factor.

• The initialsCSAPRmean or refer to Cross-State Air Pollution Rule.

• The initialsDAAmean or refer to Dry Absorbent Addition.

• The initialsDPCSmean or refer to digital process control system.

• The initialsD-Rmean or refer to Dresser-Rand.

• The initialsDSImean or refer to dry sorbent injection.

• The initialsECmean or refer to elemental carbon.

• The initialsEGUmean or refer to Electric Generating Units.

• The wordsEPA, we, usorourmean or refer to the United States Environmental Protection Agency.

• The initialsESPmean or refer to electrostatic precipitator.

• The initialsFCCUmean or refer to fluid catalytic cracking unit.

• The initialsFGDmean or refer to flue gas desulfurization.

• The initialsFGRmean or refer to flue gas recirculation.

• The initialsFIPmean or refer to Federal Implementation Plan.

• The initialsFLMsmean or refer to Federal Land Managers.

• The initialsHARmean or refer to hydrated ash reinjection.

• The initialsHDSCRmean or refer to high-dust selective catalytic reduction.

• The initialsHCmean or refer to hydrocarbons.

• The initialsgr/scfmean or refer to grains per standard cubic foot.

• The initialsIMPROVEmean or refer to Interagency Monitoring of Protected Visual Environments monitoring network.

• The initialsIPMmean or refer to Integrated Planning Model.

• The initialsIWAQMrefer to Interagency Workgroup on Air Quality Modeling.

• The initialsLDSCRmean or refer to low-dust selective catalytic reduction.

• The initialsLEAmean or refer to low excess air.

• The initialsLNBsmean or refer to low NOXburners.

• The initialsLSDmean or refer to lime spray drying.

• The initialsLSFOmean or refer to limestone forced oxidation.

• The initialsLTSmean or refer to Long-Term Strategy.

• The initialsMACTmean or refer to maximum achievable control technology.

• The initialsMATBmean or refer to Montanan's Against Toxic Burning.

• The initialsMDEQmean or refer to Montana's Department of Environmental Quality.

• The initialsMDFmean or refer to medium density fiberboard.

• The initialsMISOmean or refer to Midwest Independent Transmission System Operator.

• The initialsMDUmean or refer to Montana-Dakota Utilities Company.

• The initialsMELmean magnesium-enhanced lime.

• The initialsMKFmean or refer to mid-kiln firing of solid fuel.

• The wordsMontanaandStatemean the State of Montana.

• The initialsMSCCmean or refer to Montana Sulphur and Chemical Company.

• The initialsNAAQSmean or refer to National Ambient Air Quality Standards.

• The initialsNCmean or refer to North Carolina.

• The initialsNDmean or refer to North Dakota.

• The initialsNEImean or refer to National Emission Inventory.

• The initialsNESHAPmean or refer to National Emission Standards for Hazardous Air Pollutants.

• The initialsNH 3mean or refer to ammonia.

• The initialsNO Xmean or refer to nitrogen oxides.

• The initialsNPmean or refer to National Park.

• The initialsNPSmean or refer to National Parks Service.

• The initialsNSCRmean or refer to non-selective catalytic reduction.

• The initialsNSPSmean or refer to New Source Performance Standards.

• The initialsNWRmean or refer to National Wildlife Reserve.

• The initialsOMBmean or refer to the Office of Management and Budget.

• The initialsOCmean or refer to organic carbon.

• The initialsOFAmean or refer to overfire air.

• The initialsPCmean or refer to pulverized coal.

• The initialsPH/PCmean or refer to preheater/precalciner.

• The initialsPMmean or refer to particulate matter.

• The initialsPM 2.5mean or refer to particulate matter with an aerodynamic diameter of less than 2.5 micrometers (fine particulate matter).

• The initialsPM 10mean or refer to particulate matter with an aerodynamic diameter of less than 10 micrometers (coarse particulate matter).

• The initialsPMCDmean or refer to particulate matter control device.

• The initialsppbmean or refer to parts per billion.

• The initialsppmmean or refer to parts per million.

• The initialsPRBmean or refer to Powder River Basin.

• The initialsPSATmean or refer to Particulate Matter Source Apportionment Technology.

• The initialsPSDmean or refer to Prevention of Significant Deterioration.

• The fractionQ/Dmeans quantity of emissions over distance.

• The initialsRAAmean or refer to relative accuracy audit.

• The initialsRATAmean or refer to relative accuracy test audit.

• The initialsRAVImean or refer to Reasonably Attributable Visibility Impairment.

• The initialsRICEmean or refer to Reciprocating Internal Combustion Engines.

• The initialsRMCmean or refer to Regional Modeling Center.

• The initialsROFAmean or refer to rotating opposed fire air.

• The initialsRPmean or refer to Reasonable Progress.

• The initialsRPGorRPGsmean or refer to Reasonable Progress Goal(s).

• The initialsRPOsmean or refer to regional planning organizations.

• The initialsRRImean or refer to rich reagent injection.

• The initialsRSCRmean or refer to regenerative selective catalytic reduction.

• The initialsSCOTmean or refer to Shell Claus Off-Gas Treatment.

• The initialsSCRmean or refer to selective catalytic reduction.

• The initialsSDAmean or refer to spray dryer absorbers.

• The initialsSIPmean or refer to State Implementation Plan.

• The initialsSMOKEmean or refer to Sparse Matrix Operator Kernel Emissions.

• The initialsSNCRmean or refer to selective non-catalytic reduction.

• The initialsSO 2mean or refer to sulfur dioxide.

• The initialsSOFAmean or refer to separated overfire air.

• The initialsSRUmean or refer to sulfur recovery unit.

• The initialsTACmean or refer to Texas Administrative Code.

• The initialsTESCRmean or refer to tail-end selective catalytic reduction.

• The initialsTCEQmean or refer to Texas Commission on Environmental Quality.

• The initialstpymean tons per year.

• The initialsTSDmean or refer to Technical Support Document.

• The initialsURPmean or refer to Uniform Rate of Progress.

• The initialsUSFWSmean or refer to U.S. Fish and Wildlife Service.

• The initialsVOCmean or refer to volatile organic compounds.

• The initialsWAmean or refer to Wilderness Area.

• The initialsWEGmean or refer to WildEarth Guardians.

• The initialsWEPmean or refer to Weighted Emissions Potential.

• The initialsWETAmean or refer to Western Environmental Trade Association.

• The initialsWRAPmean or refer to the Western Regional Air Partnership.

• The initialsYELPmean or refer to Yellowstone Energy Limited Partnership.

Table of Contents I. Background II. Basis for Our Final Action III. Final Action IV. Issues Raised by Commenters and EPA's Responses A. Comments on Modeling B. General Comments on BART C. Comments on Cement Kilns D. Comments on Ash Grove E. Comments on Holcim F. Comments on CFAC G. Comments on Colstrip Units 1 and 2 H. Comments on Corette I. Comments on Reasonable Progress and Long Term Strategy J. Comments on Colstrip 3 and 4 K. Comments on Devon Energy L. Comments on Montana Dakota Utilities M. Comments on Montana Sulphur and Chemical Company N. Comments on Health, Ecosystem Benefits, Other Pollutants, and Coal Ash O. General Comments Supporting Our Proposal or for Stricter Controls P. General Comments That The Proposal Is Too Stringent Q. Comments on Visibility Improvement and Other Causes of Haze R. Comments on Cost, Economic Impact, Jobs and Price to Consumers S. Comments About Other Forms of Energy T. Other Miscellaneous Comments V. Changes From Proposed Rule and Reasons for the Changes A. Emission Limits for Corette B. Changes to 40 CFR 52.1396(c)(2)—Emission Limitations for Cement Kilns: C. Change to 40 CFR 52.1396(d)—Compliance date: D. Change to 40 CFR 52.1396(e)(3)—CEMS for cement kilns: E. Change to 40 CFR 52.1396(e)(4)(ii)—Compliance determination methods for SO2and NOXat cement kilns: F. Change to 40 CFR 52.1396(f)(1) and (f)(2)—Compliance determinations forPM BART limits at EGUs and cement kilns: G. Change to 40 CFR 52.1396(f)(2)—Compliance determinations for cement kiln PM BART limits: H. Change to 40 CFR 52.1396(h)(6)—Recordkeeping requirements for cement kilns: I. Change to 40 CFR 52.1396(i)—Reporting: J. Change to 40 CFR 52.1396(i)(1) and (i)(2)—Reporting for CEMS for SO2and NOX: K. Changes to 40 CFR 52.1396 for Devon Energy, Blaine County #1 Compressor Station VI. Statutory and Executive Order Reviews I. Background

We signed our notice of proposed rulemaking on March 20, 2012, and it was published in theFederal Registeron April 20, 2012. In that notice, we proposed a FIP to address regional haze in the State of Montana for the first implementation period (through 2018) including determinations of Best Available Retrofit Technology (BART) for specific sources subject to that requirement. 77 FR 23988. Montana did not submit a SIP, knowing that as a consequence EPA would be required to propose and finalize a FIP. A detailed explanation of the CAA's visibility requirements and the Regional Haze Rule as it applies to Montana was provided in the notice of proposed rulemaking and will not be restated here. In that notice, we also proposed to approve a revision to the Montana SIP submitted by the State of Montana through the Montana Department of Environmental Quality on February 17, 2012. The State's submittal contained revisions to the Montana Visibility Plan that included amendments to the “Smoke Management” section, which adds a reference to Best Available Control Technology (BACT) as the visibility control measure for open burning as currently administered through the State's air quality permit program. EPA's rationale for proposing approval of the revisions to the Montana Visibility Plan that included amendments to the “Smoke Management” section was described in detail in the proposal and will not be restated here. We note that in the future, Montana retains the option of submitting a SIP meeting the requirements of the Regional Haze Rule, to replace the FIP.

II. Basis for Our Final Action

We have fully considered all significant comments on our proposal, and, except as noted in section V, below, have concluded that no other changes from our proposal are warranted. Our action is based on an evaluation of Montana's Visibility SIP submittal and our FIP against the regional haze requirements at 40 CFR 51.300—51.309 and CAA sections 169A and 169B. All general SIP requirements contained in CAA section 110, other provisions of the CAA, and our regulations applicable to this action were also evaluated. The purpose of this action is to ensure compliance with these requirements. Our authority for action on Montana's Visibility SIP submittal is based on CAA section 110(k). Our authority to promulgate our FIP is based on CAA section 110(c).

III. Final Action

With this final action we are approving Montana's submittal containing revisions to the “Smoke Management” section of Montana's Visibility Plan that was submitted by the State through the Montana DEQ on February 17, 2012. The SIP includes amendments to the “Smoke Management” section, which adds a reference to BACT as the visibility control measure for open burning as currently administered through the State's air quality permit program as meeting the requirement of 40 CFR 308(d)(3)(v) to consider smoke management techniques for agricultural and forestry management purposes including plans as they currently exist within the state for these purposes. We are promulgating a FIP for the remaining parts of the regional haze requirements. Table 1 shows the control technologies, associated cost, and emission reductions for each source that is subject to the FIP.

Table 1—Control Technologies, Cost, Emissions Reductions and Cost-Effectiveness Source Technology1 Total capital cost ($) Total annualized cost ($) Annual NOX/SO2emissions reductions (tpy) Cost
  • effectiveness
  • ($/ton)
  • Ash Grove Cement LNB + SNCR 1,191,632 2,238,893 1,088 NOX 2,058 Holcim, Inc SNCR 1,312,800 650,399 556 NOX 1,170 Colstrip Unit 1 SOFA + SNCR 13,380,673 3,278,964 2,097 NOX 1,564 Colstrip Unit 2 Lime Injection + Additional Scrubber Vessel 28,000,000 4,093,200 4,486 SO2 912 Colstrip Unit 2 SOFA + SNCR 13,380,673 3,256,127 2,072 NOX 1,571 Colstrip Unit 2 Lime Injection + Additional Scrubber Vessel 28,000,000 4,093,200 4,129 SO2 991 Devon Energy, Blaine County #1 Compressor Station, Engine #1 NSCR -- 105,000 335 NOX 282 Devon Energy, Blaine County #1 Compressor Station, Engine #2 NSCR -- 105,000 335 NOX 282 Cumulative Total Annual Cost 13,727,583 -- Total Capital Cost was not calculated. 1The technology listed is the technology evaluated as BART, but sources can choose to use another technology or combination of technologies to meet established emission limits. Also where additional control technologies are not required, existing controls may still be necessary to meet established emission limits.
    IV. Issues Raised by Commenters and EPA's Responses

    This action addresses comments on the Montana Regional Haze FIP. The publication of EPA's proposed rule on April 20, 2012 resulted in a 60-day public comment period that ended on June 19, 2012. We held four public hearings for this proposal. Two hearings were held in Helena, Montana on Tuesday, May 1, 2012 and two hearings were held in Billings, Montana onWednesday, May 2, 2012. During the public comment period we received numerous written comments from individual citizens, members of various organizations, and also from Ash Grove Cement (Ash Grove), Columbia Falls Aluminum Corporation (CFAC), EarthJustice, the U.S. Fish and Wildlife Service (USFWS), Holcim Inc. (Holcim), Montana Dakota Utilities (MDU), Montana Sulphur and Chemical Company, the National Parks Service (NPS), the owners of Colstrip Units 1-4, the State of Montana, and WildEarth Guardians (WEG). We have reviewed the comments and provided our responses below. Transcripts from the public hearings and full copies of the comment letters are available in the docket for review.

    A. Comments on Modeling

    Comment:PPL and others stated that the proposed BART at Colstrip 1 and 2 for both NOXand SO2would result in no reasonably anticipated visibility benefit, even assuming that EPA's emissions reduction estimates and modeling are correct. In one specific comment, the commenter stated:

    A projected 0.066 dv is not a visibility improvement that `may reasonably be anticipated to result from the use' of additional scrubber vessels at Colstrip Units 1 and 2. 42 U.S.C. 7491(g)(2). Such an insignificant projected visibility change is beyond the modeling capability of the CALPUFF model version EPA used and is far below the threshold for human perceptibility.

    Response:We disagree that any controls required by our action must demonstrate a perceptible visibility improvement. In a situation where the installation of BART may not result in a perceptible improvement in visibility, the visibility benefit may still be significant. The Regional Haze Rule states:

    even though the visibility improvement from an individual source may not be perceptible, it should still be considered in setting BART because the contribution to haze may be significant relative to other source contributions in the Class I area. Failing to consider less-than-perceptible contributions to visibility impairment would ignore the CAA's intent to have BART requirements apply to sources that contribute to, as well as cause, such impairment. 70 FR 39129.

    Visibility impacts below the thresholds of perceptibility cannot be ignored because regional haze is produced by a multitude of sources and activities which are located across a broad geographic area. As stated in our proposal, with respect to Colstrip 1 and 2, we weighed the relatively low costs for lime injection with the additional scrubber vessel against the anticipated visibility impacts and determined that the cost was justified by the visibility improvement. Similarly, we weighed the relatively low cost of separated overfire air (SOFA) + selective noncatalytic reduction (SNCR) against the anticipated visibility benefit and determined that the cost was justified by the visibility benefit.

    We respond to the modeling capabilities of CALPUFF in a response to a later comment.

    Comment:A commenter asserted that EPA's modeling assumes constant levels of ammonia and failed to consider monitoring data showing that ammonia levels are lower during the winter months.

    Response:EPA recognizes that there can be seasonal variability in ambient ammonia concentrations and that it is preferable to use ambient ammonia measurements when such data are available rather than using default background ammonia concentrations. Ammonia monitoring data is not available in Montana, however, ammonia monitoring data is available in western North Dakota at the Beulah monitoring site. Theodore Roosevelt NP, located in western North Dakota, is impacted by Montana BART sources and EPA determined that it would be more appropriate to use the North Dakota ammonia monitoring data instead of using CALPUFF default ammonia concentrations. Therefore EPA used monthly average measured ammonia concentrations shown in Table 2 that were measured by North Dakota at their Beulah monitoring site.1 The monthly average ammonia concentrations values were derived from data collected during years 2001-2002 and the ambient data were filtered to eliminate data from wind directions associated with sources causing a local bias. North Dakota concluded in its regional haze modeling analysis that these monthly average ammonia values are generally representative of background ammonia concentrations in western North Dakota. As a result, we did not assume a constant level of ammonia as asserted by the commenter, and we did represent seasonal variability in ammonia concentrations.

    1Protocol for BART-Related Visibility Impairment Modeling Analyses in North Dakota (Final), North Dakota Department of Health, Division of Air Quality, 1200 Missouri Avenue Bismarck, ND (Nov 2005), p 32-33.

    Additionally, EPA used the POSTUTIL2 program with the Ammonia Limiting Method (ALM) to post-process the CALPUFF output to correct the assumption of constant ammonia availability in the model. The CALPUFF model represents multiple plumes that can overlap. The default model approach assumes that background ammonia is fully available to form nitrate in each plume. The ALM method corrects this assumption by partitioning the ammonia between overlapping plumes. Therefore, EPA has fully accounted for non-constant ammonia levels by using monthly measured background ammonia and by using the ALM in the analysis of CALPUFF model results.

    2POSTUTIL is a part of the suite of programs associated with the CALPUFF modeling system and is used to repartition ammonia in overlapping puffs. The model is available at:http://www.src.com/calpuff/calpuff1.htm.

    Table 2—Monthly Ammonia Background Concentrations Month Value
  • (ppb)
  • Jan 1.22 Feb 1.23 Mar 1.60 Apr 1.94 May 2.29 Jun 1.63 Jul 1.65 Aug 1.69 Sep 0.98 Oct 1.04 Nov 1.37 Dec 1.06

    Comment:A commenter stated that EPA failed to acknowledge uncertainty in the CALPUFF model at short distances, and the commenter further argues that model uncertainty increases at distances greater than 200 km and has a tendency to over predict impacts at greater distances.

    Response:The Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 report (EPA, 1998)3 reviewed model performance evaluations of CALPUFF as a function of distance from the source and concluded that:

    3Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Report and Recommendations for Long-Range Transport Impacts. EPA-454/R-98-019. U.S. Environmental Protection Agency. Research Triangle Park, NC (“IWAQM Phase II Report”) (1998), p 18.

    Based on the tracer comparison results presented in Section 4.6, it appears that CALPUFF provides reasonable correspondence with observations for transport distances of over 100 km. Most of these comparisons involved concentration values averaged over 5 to 12 hours. The CAPTEX comparisons, which involved comparisons at receptors that were 300 km to 1000 km from the release, suggest that CALPUFF can overestimate surface concentrations by a factor of 3 to 4. Use ofthe puff splitting option in CALPUFF might have improved these comparisons, but there are serious conceptual concerns with the use of puff dispersion for very long-range transport (300 km and beyond). As the puffs enlarge due to dispersion, it becomes problematic to characterize the transport by a single wind vector, as significant wind direction shear may well exist over the puff dimensions. With the above thoughts in mind, IWAQM recommends use of CALPUFF for transport distances of order 200 km and less. Use of CALPUFF for characterizing transport beyond 200 to 300 km should be done cautiously with an awareness of the likely problems involved.

    Therefore, we modeled Class I areas within 300 km of each BART sources but did not model impacts at distances exceeding 300 km.

    EPA has acknowledged that there is uncertainty in the CALPUFF model predicted visibility impacts. However, the CALPUFF model can both underpredict and overpredict visibility impacts. For example, in a presentation for the 2010 annual Community Modeling and Analysis System conference, Anderson et al. (2010)4 found that the CALPUFF model frequently predicted lower nitrate concentrations compared to the CAMx photochemical grid model which has a much more rigorous treatment of photochemical reactions. EPA recognized the uncertainty in the CALPUFF modeling results when EPA made the decision, in the final BART Guidelines, to recommend that the model be used to estimate the 98th percentile visibility impairment rather than the highest daily impact value. While recognizing the limitations of the CALPUFF model in the BART Guidelines Preamble, EPA concluded that, for the specific purposes of the Regional Haze Rule's BART provisions, CALPUFF is sufficiently reliable to inform the decision making process. The Preamble states:

    4Anderson, B., K. Baker, R. Morris, C. Emery, A. Hawkins, E. Snyder “Proof-of-Concept Evaluation of Use of Photochemical Grid Model Source Apportionment Techniques for Prevention of Significant Deterioration of Air Quality Analysis Requirements” Presentation for Community Modeling and Analysis System (CMAS) 2010 Annual Conference, (October 11-15, 2010) can be found athttp://www.cmascenter.org/conference/2010/agenda.cfm.

    Because of the scale of the predicted impacts from these sources, CALPUFF is an appropriate or a reasonable application to determine whether such a facility can reasonably be anticipated to cause or contribute to any impairment of visibility. In other words, to find that a source with a predicted maximum impact greater than 2 or 3 deciviews meets the contribution threshold adopted by the States does not require the degree of certainty in the results of the model that might be required for other regulatory purposes. In the unlikely case that a State were to find that a 750 MW power plant's predicted contribution to visibility impairment is within a very narrow range between exemption from or being subject to BART, the State can work with EPA and the FLM to evaluate the CALPUFF results in combination with information derived from other appropriate techniques for estimating visibility impacts to inform the BART applicability determination. Similarly for other types of BART eligible sources, States can work with the EPA and FLM to determine appropriate methods for assessing a single source's impacts on visibility.

    77 FR 39123.

    Therefore, given that the IWAQM guidance provides for the use of the CALPUFF model at receptor distances of up to 200 to 300 km, and given that EPA has already addressed uncertainty in the CALPUFF model, we believe it is reasonable to use CALPUFF to evaluate visibility impacts up to 300 km.

    Comment:A commenter stated that the CALPUFF model cannot accurately predict visibility changes at the levels EPA predicted for Holcim using indirect firing alone (0.125 deciview) or even for the additional improvement from the combination of SNCR + indirect firing as compared to SNCR alone. The commenter believes that the EPA predicted visibility improvement of 0.424 deciview for the combination of SNCR + indirect firing is within the uncertainty range of the CALPUFF model and cannot reliably predict visibility improvements.

    Response:We disagree. EPA has previously addressed the issue of uncertainty in the CALPUFF model. EPA recognized the uncertainty in the CALPUFF modeling results when EPA made the decision in the final BART Guideline to recommend that the model be used to estimate the 98th percentile visibility impairment rather than the highest daily impact value. While recognizing the limitations of the CALPUFF model in the Preamble, EPA concluded that, for the specific purposes of the Regional Haze Rule's BART provisions, CALPUFF is sufficiently reliable to inform the decision making process. 70 FR 39123. We continue to maintain that it is appropriate to use CALPUFF for BART modeling for Holcim and other Montana BART sources.

    Comment:Some commenters stated that we should have modeled impacts to additional Class I areas. Some commenters stated that EPA should have modeled visibility impacts on Class I areas at a distance of up to 500 km from the BART source and some commenters specified certain Class I areas that they thought should be included in the modeling for a particular source.

    Some commenters stated that the Western Regional Air Partnership (WRAP) subject to BART modeling indicated impacts from BART sources to additional Class I areas that we did not assess. One commenter stated that when assessing the impacts from the Big Stone I facility in the South Dakota SIP, EPA evaluated visibility as far away as Badlands National Park (NP), 470 km, Theodore Roosevelt NP, 555 km, and Boundary Waters Wilderness Area (WA) and Voyageurs NP, 431 and 438 km, respectively, and the commenter stated that, EPA should evaluate visibility impacts at more distant Class I areas for the Montana FIP.

    Response:We modeled all Class I areas within 300 km of the BART source. As discussed in a response to a previous comment, the IWAQM Phase 2 report concluded that CALPUFF can overestimate surface concentrations at distances of 300 to 1,000 km by a factor of 3 to 4. Therefore, IWAQM recommends use of CALPUFF for transport distances of approximately 200 km or less. Use of CALPUFF for characterizing transport beyond 200 to 300 km should be done cautiously with an awareness of the likely problems involved. Therefore, we modeled Class I areas within 300 km of each BART source. We did not model impacts at distances exceeding 300 km.

    In the case of the Big Stone I facility in South Dakota, there were no Class I areas within a distance of 300 km of the source. Therefore, the State and the facility agreed in their modeling protocol to evaluate visibility impacts at more distant sources by using a non-regulatory option in CALPUFF called “puff splitting”. As discussed in the IWAQM Guidance,5 the use of the puff splitting option in CALPUFF might improve model performance at long distances, but there are also serious conceptual concerns with the use puff splitting to represent puff dispersion for very long-range transport at distances of more than 300 km. EPA concurred with South Dakota on this approach for Big Stone I because there were no Class I areas within 300 km of the source, and EPA approved the South Dakota SIP using these modeling results. In the case of Montana, there are several Class I areas less than 300 km from each BART source, and EPA based its analysis on CALPUFF visibility model results for these areas.

    5IWAQM Phase 2 report, p. 27.

    EPA did not use the non-regulatory puff splitting option in CALPUFF to model more distant sources because ofthe greater uncertainty in model results at distances of more than 300 km, as we have explained in previous responses.

    While WRAP performed CALPUFF modeling at Class I areas more distant than 300 km from Colstrip, WRAP also recognized the larger uncertainty in the model results for distances greater than 300 km. and included the following caveat in their modeling protocol:

    Relevant guidance suggests that the CALPUFF model is generally applicable at distances from 50 km to 300 km downwind and may be used for distance less than 50 km when complex flows exist on a case by case basis. [citation omitted] Class I areas in the west generally are located in complex terrain resulting in complex flows. Consequently, the BART screening modeling conducted by the RMC will include results for potential BART eligible sources that reside within 50 km of a Class I area. The WRAP RMC BART screening modeling may also apply CALPUFF to downwind distances greater than 300 km. When providing results to the States, the downwind distance between the BART source and the Class I area will be included, and a recommendation from the RMC as to the utility of applying the results for Class I areas less than 50 km and greater than 300 km from the source. The individual States will need to make their own regulatory assessment of the applicability of the model results at those distances less than 50 km and greater than 300 km.6

    6CALMET/CALPUFF Protocol for BART Exemption Screening Analysis for Class I areas in the Western United States Available athttp://pah.cert.ucr.edu/aqm/308/bart/WRAP_RMC_BART_Protocol_Aug15_2006.pdf.

    It also should be noted that WRAP found smaller visibility impacts at the distances of more than 300 km compared to Class I areas at distances of less than 300 km.7 The BART Guidelines explain that if the highest modeled effects are observed at the nearest Class I area, it may not be necessary to model other Class I areas. The BART Guidelines state:

    7Summary of WRAP RMC BART Modeling for Montana, Draft #5 May 30, 2007. More information can be found athttp://pah.cert.ucr.edu/aqm/308/bart.shtml.

    One important element of the protocol is in establishing the receptors that will be used in the model. The receptors that you use should be located in the nearest Class I area with sufficient density to identify the likely visibility effects of the source. For other Class I areas in relatively close proximity to a BART-eligible source, you may model a few strategic receptors to determine whether effects at those areas may be greater than at the nearest Class I area. For example, you might choose to locate receptors at these areas at the closest point to the source, at the highest and lowest elevation in the Class I area, at the IMPROVE monitor, and at the approximate expected plume release height. If the highest modeled effects are observed at the nearest Class I area, you may choose not to analyze the other Class I areas any further as additional analyses might be unwarranted.

    70 FR 39170.

    Comment:Commenters stated that EPA should have added the visibility impacts at each Class I area to assess cumulative visibility impacts.

    Response:Contrary to the commenter's assertion, we did assess cumulative visibility impacts. In our analysis of visibility impacts, we considered the visibility improvement at all Class I areas within 300 km of the subject BART unit. For example, in our analysis of BART control options for Corette, we considered the visibility improvement at all Class I areas within 300 km (Gates of the Mountains WA, North Absaroka WA, Red Rock Lakes WA, Teton WA, UL Bend WA, Washakie WA, and Yellowstone NP). 77 FR 24042 and 77 FR 24046. In our proposal, for each of the BART sources we assessed the visibility improvement at each Class I area within 300 km of the source associated with the controls under consideration, as well as the number of days with a greater than 0.5 deciview impact at each of these Class I areas. Therefore, our proposed rule did not ignore the visibility improvement that would be achieved at areas other than the most impacted Class I area, and we disagree with the assertions that we did not consider the impacts at multiple Class I areas. We did, however, in the proposed rule focus on the visibility benefits at those Class I areas with the most meaningful visibility impacts in determining whether NOXor SO2controls should be determined to be BART. We took a similar approach for all the Montana BART units. We did not ignore the visibility benefits at the other Class I areas but did not consider the benefits sufficient to warrant a change in our determination as to the appropriate level of control.

    Comment:USFWS stated that for the three SO2control alternatives, EPA made judgments on cost per deciview based on only the most impacted Class I area, Washakie WA and that USFWS continued to believe that it is appropriate to consider both the degree of visibility improvement in a given Class I area as well as the cumulative effects of improving visibility across all of the Class I areas affected. USFWS stated that it does not make sense to use the same metric to evaluate the effects of reducing emissions from a BART source that impacts only one Class I area as for a BART source that impacts multiple Class I areas and that it does not make sense to evaluate impacts at one Class I area, while ignoring others that are similarly significantly impaired. USFWS stated that if emissions from Corette are reduced, the benefits will be spread well beyond only the most impacted Class I area, and this must be accounted for. USFWS stated that, in the context of the multiple Class I areas that are affected by Corette, the Lime Spray Dryer (LSD) SO2control alternative, the cumulative Class I area impact is $12.7 million per deciview of visibility improvement and costs $4,981 per ton of SO2removed USFWS stated that LSD should be considered as being a viable candidate for BART for Corette. USFWS made similar comments regarding NOXcontrols for Corette.

    Response:We disagree. In our analysis of visibility impacts, we considered the visibility improvement at all Class I areas within 300 km of the subject BART unit. As explained in the response to the previous comment, in our analysis of BART control options for Corette, we considered the visibility improvement at all Class I areas within 300 km. In our proposal, for each of the BART sources we assessed the visibility improvement at each Class I area within 300 km of the source associated with the controls under consideration, as well as the number of days with a greater than 0.5 deciview impact at each of these Class I areas. Therefore, our proposed rule did not ignore the visibility improvement that would be achieved at areas other than the most impacted Class I area, and we disagree with the assertions that we did not consider the impacts at multiple Class I areas. We did, however, in the proposed rule focus on the visibility benefits at those Class I areas with the most meaningful visibility impacts in determining whether NOXor SO2controls should be determined to be BART. We did not ignore the visibility benefits at the other Class I areas but did not consider the benefits sufficient to warrant a change in our determination as to the appropriate level of control. As we explained in other responses, we did not use the $/deciview ratio as a basis for our decision.

    Comment:EarthJustice's consultant Air Resources Specialists (ARS) performed additional analysis on possible visibility benefits of SCR at Colstrip Units 1 and 2 combined with the benefits of BART controls on SO2emissions. The commenter stated that the ARS analysis “demonstrates that EPA's analysis of visibility benefits of selective catalytic reduction (SCR) controls is incomplete and inadequate.” The commenter also stated, “the evidence demonstrates that with SCR and SO2controls, the visibility impairment at UL Bend WA and Theodore Roosevelt NP attributable toColstrip would be virtually eliminated, the very goal of the CAA haze requirements.”

    The commenter also stated that when SCR + SOFA is coupled with a dry scrubber/baghouse, it is likely that Corette would no longer have any noticeable impact on haze in any Class I area, and this result complies with the Congressional directive to eliminate haze in Class I areas.

    Response:We disagree that our analysis was incomplete or inadequate. We analyzed visibility benefits for both SO2and NOXemissions reductions following procedures established in the BART Guidelines, and we proposed emissions reductions consistent with the five factor analysis. The Regional Haze Rule has a goal that anthropogenic visibility impairment be eliminated by 2064; however, it does not require that all anthropogenic contributions to visibility impacts be fully eliminated in the near term, nor is that the goal of the BART element of the Regional Haze program. 40 CFR 51.308 (e)(1)(ii)(A) requires that EPA consider the cost of compliance; the energy and nonair quality environmental impacts; any pollution control equipment in use at the source; the remaining useful life of the source; and the degree of improvement which may be reasonably anticipated to result from the use of such technology. Visibility improvement is only one of the five factors that are required to be considered. Our proposed BART controls achieve significant reductions in contributions to visibility impairment while also considering other components of the five factor analysis.

    Comment:EarthJustice stated that, “ARS concluded that the incremental benefit of SCR compared to SNCR at Colstrip Units 1 and 2 is larger when viewed in combination with the SO2emission controls at either emission rate.”

    Response:ARS estimated the relative improvement in SCR compared to SNCR for the case with baseline SO2emissions and for the case with our proposed BART SO2emissions. The ARS analysis showed that the incremental improvement in SCR compared to SNCR was almost identical for the 98% worst days regardless of the level of SO2emissions used. For example, in EPA's analysis the incremental improvement of SCR over SNCR for Theodore Roosevelt NP was 0.27, 0.23, and 0.28 deciview, respectively, for 2006, 2007 and 2008. The ARS analysis found incremental improvements of 0.28, 0.26, and 0.28 deciview, respectively, for 2006, 2007 and 2008. Moreover, ARS did not perform additional CALPUFF simulations for this analysis, but only combined estimates of extinction contributions from different CALPUFF simulations.

    Comment:EarthJustice stated that that we aggregated Colstrip Units 1 and 2 for assessing visibility benefits of SNCR, but arbitrarily kept our assessment of benefits of SCR segregated by unit.

    Response:We disagree. Modeling was performed in the same manner for SCR as for SNCR. The modeling protocol, results, and final report were available in the docket. Our evaluation of the visibility benefits was made in consideration of all of the modeling results, which includes a visibility improvement assessment for application of SCR at Colstrip Units 1 and 2 individually, as well as an assessment of the total visibility benefit from application of SCR at both units collectively.

    Comment:A commenter stated that we failed to examine the collective visibility benefit of SCR in combination with SO2upgrades at Colstrip Units 1 and 2.

    Response:We examined the individual benefits of NOXand SO2controls to be able to assess the difference between pollutant-specific control options. Our evaluation of the visibility benefits was made in consideration of all of the modeling results.

    Comment:EarthJustice stated that their contractor (ARS) performed AERMOD simulations to evaluate the impacts of Colstrip SO2emissions relative to the 1-hour average SO2National Ambient Air Quality Standard (NAAQS) and reported modeled violations of the SO2NAAQS.

    Response:EPA will address compliance with the 1-hour average SO2NAAQS separately from Regional Haze requirements. It is beyond the scope of this rulemaking. It will be addressed by EPA at a later date.

    Comment:Holcim commented that EPA discarded all prior modeling and developed a new modeling analysis in 2011. Holcim stated that EPA did not explain why it used a new modeling analysis and that EPA's BART conclusions are therefore based on modeling that is not transparent and not available for review.

    Response:We disagree. As we explained in our proposal, we used CALPUFF modeling to evaluate emissions control scenarios that were consistent with the application of control scenarios for the Montana sources that were subject to BART. We did this because we were unable to obtain the modeling files from some of the sources and we wanted each source to be modeled consistently. The modeling protocol, final report, and all related files were available for review in the docket.

    Comment:The Western Environmental Trade Organization (WETA) commented that the EPA recently approved the SIP for regional haze developed by the State of North Dakota. WETA explained that the North Dakota plan relied on extensive modeling that demonstrated emissions control technology installations at certain facilities would result in insignificant improvement in visibility. WETA requested that the EPA develop a visibility plan for Montana that offers the same flexibility and cost-effective standards included in North Dakota's plan.

    Response:WETA did not explain what flexibility it was seeking; therefore, we are not able to evaluate whether such flexibility could be accommodated. To the extent that WETA is stating that our proposed requirements are not cost-effective, we disagree. To the extent that WETA is stating that we are being inconsistent with decisions we made for regional haze in North Dakota, we disagree. We have responded to more specific comments on the cost-effectiveness of controls elsewhere.

    Comment:The commenter stated that EPA's proposed BART determinations for Colstrip Units 1& 2 are erroneous because EPA's modeling failed to include actual air quality measurements, including visual quality measurements, in its inputs to its regional haze model. The commenter further stated that real air quality data for Class I areas is critical to determining what the degree of visibility improvement may be in a given Class I area.

    Response:EPA used ambient monitoring data to evaluate the CMAQ and CAMx grid model simulations that were used for modeling the uniform rate of progress toward natural visibility conditions. However, the commenter appears to be referring specifically to the CALPUFF model simulations used to evaluate visibility impacts of BART sources. The BART Guidelines require that visibility impacts from BART sources be evaluated in comparison to natural visibility conditions. The procedures used to estimate natural visibility conditions are described in the “Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Rule.”8 It would beinappropriate to use ambient monitoring data for current degraded visibility conditions in the evaluation of BART source visibility impacts. EPA previously considered and responded to the comment that current visibility conditions should be used in BART source evaluations in 40 CFR part 51, appendix Y, promulgated at 70 FR 39104. EPA considered the approach of assessing a BART-eligible source's impacts on visibility by using current or near-term future conditions, and EPA determined that BART visibility impacts should be evaluated in comparison to natural background visibility. In the final rulemaking EPA wrote:

    8Guidance for Estimating Natural Visibility Conditions Under the Regional Haze Rule, U.S. Environmental Protection Agency, September 2003.Can be found at:http://www.epa.gov/ttncaaa1/t1/memoranda/rh_envcurhr_gd.pdf.

    Using existing conditions as the baseline for single source visibility impact determinations would create the following paradox: The dirtier the existing air, the less likely it would be that any control is required. This is true because of the nonlinear nature of visibility impairment. In other words, as a Class I area becomes more polluted, any individual source's contribution to changes in impairment becomes geometrically less. Therefore the more polluted the Class I area would become, the less control would seem to be needed from an individual source. We agree that this kind of calculation would essentially raise the “cause or contribute” applicability threshold to a level that would never allow enough emission control to significantly improve visibility. Such a reading would render the visibility provisions meaningless, as EPA and the States would be prevented from assuring “reasonable progress” and fulfilling the statutorily-defined goals of the visibility program. Conversely, measuring improvement against clean conditions would ensure reasonable progress toward those clean conditions.

    70 FR 39124.

    Therefore, EPA correctly used estimates of natural visibility conditions in our evaluation of BART source visibility impacts, and we disagree with the comment that we failed to appropriately use air quality data at Class I areas.

    Comment:EarthJustice stated that they do not agree with EPA's approach to use the fifth factor in determining the degree of visibility improvement from emissions control technologies where EPA adds an additional incremental benefit factor with an apparent but unstated threshold for improvement sufficiency that is contrary to the purpose and direction of the CAA.

    Response:We disagree that we only evaluated visibility benefit on an incremental basis and that we used a threshold for improvement sufficiency. In the proposed FIP, we included tables showing the visibility improvement for control options as compared to baseline conditions. Incremental improvement can be easily calculated from the data in the tables, however, we did not calculate this separately for each option. In addition, our modeling protocol, modeling report and tables of results were included in the docket.

    Comment:Commenters stated that we used incorrect baselines for modeling impacts from sources at Corette and Colstrip.

    Response:We explain our rationale for the chosen baseline periods in responses to other comments.

    B. General Comments on BART

    Comments:Montana Department of Environmental Quality (MDEQ) stated that EPA should have used a dollar-per-deciview ($/deciview) metric rather than the $/ton metric to evaluate BART and reasonable progress. MDEQ argued that the use of deciviews is consistent with the Regional Haze Rule, which expresses Reasonable Progress Goals (RPGs), baseline visibility, current visibility conditions and natural conditions in deciviews. MDEQ also referenced both the BART Guidance and the Reasonable Progress Guidance to support this argument.

    The NPS stated that one of the options suggested by the BART Guidelines to evaluate cost-effectiveness is cost/deciview and that the NPS believes that visibility improvement must be a critical factor in any program designed to improve visibility. The NPS stated that compared to the typical control cost analysis in which estimates fall into the range of $2,000-$10,000 per ton of pollutant removed, spending millions of dollars per deciview to improve visibility may appear extraordinarily expensive, but that the NPS compilation of BART analyses across the United States reveals that the average cost per deciview proposed by either a state or a BART source is $14-$18 million, with a maximum of $51 million per deciview proposed by South Dakota at the Big Stone I power plant. The NPS noted that even though it has no Class I areas, Nebraska Department of Environmental Quality has chosen $40 million/deciview as a cost criterion, which is also above the national average. The NPS compared its estimates for annual cost of adding SOFA + SCR to EPA's estimates for visibility impacts and stated that the cost-effectiveness of adding SOFA + SCR to improve visibility at the five Class I areas modeled by EPA is less than $10 million/deciview and significantly less than the $14-$18 million/deciview national average of BART proposals and determinations.

    Response:For BART, the BART Guidelines require that cost effectiveness be calculated in terms of annualized dollars per ton of pollutant removed, or $/ton. 70 FR 39167. MDEQ and the NPS are correct in that the BART Guidelines allows for the $/deciview ratio as an additional cost effectiveness metric that can be employed along with $/ton for use in a BART evaluation. However, the use of this metric further implies that additional thresholds or notions of acceptability, separate from the $/ton metric, would need to be developed for BART determinations. We have not used this metric for BART purposes because (1) It is unnecessary in judging the cost effectiveness of BART, (2) it complicates the BART analysis, and (3) it is difficult to judge. The $/deciview metric has not been widely used and is not well-understood as a comparative tool. In our experience, $/deciview values tend to be very large because the metric is based on impacts at one Class I area on one day and does not take into account the number of affected Class I areas or the number of days of improvement that result from controlling emissions. In addition, the use of the $/deciview suggests a level of precision in the CALPUFF model that may not be warranted. As a result, the $/deciview can be misleading. We conclude that it is sufficient to analyze the cost effectiveness of potential BART controls using $/t