1 Draft Technical Support Document

Kansas Area Designations for the 2010 SO 2 Primary National Ambient Air Quality Standard

Summary

Pursuant to section 107(d) of the Clean Air Act (CA A), the U.S. Environmental Protection Agency (EPA, or the Agency) must designate areas as either “unclassifiable,” “attainment,” or
“nonattainment” for the 2010 one-hour sulfur dioxid e (SO 2 ) primary national ambient air quality standard (NAAQS). The CAA defines a nonattainment a rea as one that does not meet the NAAQS or that contributes to a violation in a nearb y area. An attainment area is defined as any
area other than a nonattainment area that meets the NAAQS. Unclassifiable areas are defined as
those that cannot be classified on the basis of ava ilable information as meeting or not meeting the NAAQS.

Kansas submitted updated recommendations on Septemb er 17, 2015, ahead of a July 2, 2016, deadline for the EPA to designate certain areas est ablished by the U.S. District Court for the
Northern District of California. This deadline is t he first of three deadlines established by the court for the EPA to complete area designations for the 2010 SO 2 NAAQS. Table 1 below lists
Kansas’ recommendations and identifies the counties or portions of counties in Kansas that the EPA intends to designate by July 2, 2016 based on a n assessment and characterization of air quality through ambient air quality data, air dispe rsion modeling, other evidence and supporting information, or a combination of the above.

Table 1: Kansas’ Recommended and EPA’s Intended Des ignations
Area Kansas’

Recommended
Area Definition Kansas’

Recommended Designation EPA’s Intended

Area Definition EPA’s Intended Designation

Linn County,
Kansas All of Linn

County, Kansas Attainment Same as State’s
Recommendation Unclassifiable/
Attainment

Wyandotte County,
Kansas All of

Wyandotte County, Kansas Unclassifiable/

Attainment Same as State’s

Recommendation Unclassifiable

Shawnee County,
Kansas All of Shawnee

County, Kansas Unclassifiable Same as State’s
Recommendation Unclassifiable

Background

On June 3, 2010, the EPA revised the primary (healt h based) SO 2 NAAQS by establishing a new one-hour standard at a level of 75 parts per billio n (ppb) which is attained when the three-year average of the 99th percentile of one-hour daily ma ximum concentrations does not exceed 752

ppb. This NAAQS was published in the Federal Regist er on June 22, 2010 (75 FR 35520) and is
codified at 40 CFR 50.17. The EPA determined this i s the level necessary to protect public health with an adequate margin of safety, especially for c hildren, the elderly and those with asthma. These groups are particularly susceptible to the he alth effects associated with breathing SO 2 . The two prior primary standards of 140 ppb evaluated ov er 24 hours, and 30 ppb evaluated over an entire year, codified at 40 CFR 50.4, remain applic able. 1 However, the EPA is not currently designating areas on the basis of either of these t wo primary standards. Similarly, the secondary
standard for SO 2, set at 500 ppb evaluated over 3 hours has not been revised and the EPA is also not currently designating areas on the basis of the secondary standard.

General Approach and Schedule

Section 107(d) of the Clean Air Act requires that n ot later than one year after promulgation of a new or revised NAAQS, state governors must submit t heir recommendations for designations and boundaries to EPA. Section 107(d) also requires the EPA to provide notification to states no less than 120 days prior to promulgating an initial area designation that is a modification of a
state’s recommendation. If a state does not submit designation recommendations, the EPA will promulgate the designations that it deems appropria te. If a state or tribe disagrees with the EPA’s intended designations, they are given an opportunit y within the 120 day period to demonstrate why any proposed modification is inappropriate.

On August 5, 2013, the EPA published a final rule e stablishing air quality designations for 29
areas in the United States for the 2010 SO 2 NAAQS, based on recorded air quality monitoring data from 2009 - 2011 showing violations of the NAA QS (78 FR 47191). In that rulemaking, the EPA committed to address, in separate future action s, the designations for all other areas for which the Agency was not yet prepared to issue desi gnations.

Following the initial August 5, 2013 designations, three lawsuits were filed against the EPA in different U.S. District Courts, alleging the Agency had failed to perform a nondiscretionary duty under the CAA by not designating all portions of th e country by the June 2013 deadline. In an effort intended to resolve the litigation in one of those cases, plaintiffs Sierra Club and the
Natural Resources Defense Council and the EPA filed a proposed consent decree with the U.S.
District Court for the Northern District of Califor nia. On March 2, 2015, the court entered the
consent decree and issued an enforceable order for the EPA to complete the area designations according to the court-ordered schedule.

According to the court-ordered schedule, the EPA mu st complete the remaining designations by three specific deadlines. By no later than July 2, 2016 (16 months from the court’s order), the EPA must designate two groups of areas: (1) areas t hat have newly monitored violations of the
2010 SO 2 NAAQS and (2) areas that contain any stationary sou rces that had not been announced as of March 2, 2015 for retirement and that accordi ng to the EPA’s Air Markets Database

1 40 CFR 50.4(e) provides that the two prior primary NAAQS will no longer apply to an area one year aft er its designation under the 2010 NAAQS, except that for a reas designated nonattainment under the prior NAAQS as of August 22, 2010, and areas not meeting the requirem ents of a SIP Call under the prior NAAQS, the prior NAAQS will apply until that area submits and EPA approves a SIP providing for attainment of the 2010 NAAQS. No Kansas areas were designated nonattainment for the prior N AAQS at the time of this designation.3

emitted in 2012 either (i) more than 16,000 tons of SO 2 or (ii) more than 2,600 tons of SO 2 with an annual average emission rate of at least 0.45 po unds of SO 2 per one million British thermal units (lbs SO 2 /mmBTU). Specifically, a stationary source with a c oal-fired unit that as of January 1, 2010 had a capacity of over 5 megawatts and othe rwise meets the emissions criteria, is excluded from the July 2, 2016 deadline if it had a nnounced through a company public announcement, public utilities commission filing, c onsent decree, public legal settlement, final state or federal permit filing, or other similar me ans of communication, by March 2, 2015, that it will cease burning coal at that unit.

The last two deadlines for completing remaining des ignations are December 31, 2017, and December 31, 2020. The EPA has separately promulgat ed requirements for states and other air agencies to provide additional monitoring or modeli ng information on a timetable consistent with these designation deadlines. We expect this informa tion to become available in time to help inform these subsequent designations. These require ments were promulgated on August 21, 2015 (80 FR 51052), in a rule known as the SO 2 Data Requirements Rule (DRR).

Updated designations guidance was issued by the EPA through a March 20, 2015 memorandum from Stephen D. Page, Director, U.S. EPA, Office of Air Quality Planning and Standards, to Air Division Directors, U.S. EPA Regions I-X. This memo randum supersedes earlier designation guidance for the 2010 SO 2 NAAQS, issued on March 24, 2011, and it identifies factors that the EPA intends to evaluate in determining whether area s are in violation of the 2010 SO 2 NAAQS. The guidance also contains the factors the EPA inte nds to evaluate in determining the boundaries for all remaining areas in the country, consistent with the court’s order and schedule. These factors include: 1) Air quality characterization vi a ambient monitoring or dispersion modeling results; 2) Emissions-related data; 3) Meteorology; 4) Geography and topography; and 5) Jurisdictional boundaries. This guidance was supple mented by two technical assistance
documents intended to assist states and other inter ested parties in their efforts to characterize air quality through air dispersion modeling or ambient air quality monitoring for sources that emit
SO 2 . Notably, the EPA released its most recent version s of documents titled, “SO 2 NAAQS Designations Modeling Technical Assistance Document ” (Modeling TAD) and “SO 2 NAAQS Designations Source-Oriented Monitoring Technical A ssistance Document” (Monitoring TAD)
in December 2013.

Based on ambient air quality data collected between 2012 and 2014, no violations of the 2010
SO 2 NAAQS have been recorded in any undesignated part of the state. 2 However, there are three sources in the state meeting the emissions criteria of the consent decree for which the EPA must complete designations by July 2, 2016. In this draf t technical support document, the EPA

2 For designations based on ambient air quality monit oring data that violates the 2010 SO 2 NAAQS, the consent
decree directs the EPA to evaluate data collected b etween 2013 and 2015. Absent complete, quality assu red and certified data for 2015, the analyses of applicable areas for the EPA’s intended designations will be informed by data
collected between 2012 and 2014. States with monito rs that have recorded a violation of the 2010 SO 2 NAAQS during these years have the option of submitting co mplete, quality assured and certified data for cale ndar year 2015 by April 19, 2016 to the EPA for evaluation. If aft er our review, the ambient air quality data for the area indicates that no violation of the NAAQS occurred between 201 3 and 2015, the consent decree does not obligate th e EPA to complete the designation. Instead, we may designate the area and all other previously undesignated are as in the state on a schedule consistent with the prescribed timing of the court order, i.e., by December 31, 2017, or December 31,
2020.4

discusses its review and technical analysis of Kans as’ updated recommendations for the areas that we must designate. The EPA also discusses any intended modifications from the state’s
recommendation based on all available data before u s.

The following are definitions of important terms us ed in this document: 1) 2010 SO 2 NAAQS – The primary NAAQS for SO 2 promulgated in 2010. This NAAQS is 75 ppb, based on the three year average of the 99th percentile of the annual distribution of daily maximum one-hour average concentrations. S ee 40 CFR 50.17. 2) Design Value – a statistic computed according to th e data handling procedures of the NAAQS (in 40 CFR part 50 Appendix T) that, by compa rison to the level of the NAAQS, indicates whether the area is violating the NAAQS. 3) Designated nonattainment area – an area which the E PA has determined has violated the
2010 SO 2 NAAQS or contributed to a violation in a nearby ar ea. A nonattainment designation reflects considerations of state recomm endations and all of the information
discussed in this document. The EPA’s decision is b ased on all available information including the most recent 3 years of air quality mo nitoring data, available modeling analysis, and any other relevant information. 4) Designated unclassifiable area – an area which the EPA cannot determine based on all
available information whether or not it meets the 2 010 SO 2 NAAQS. 5) Designated unclassifiable/attainment area – an area which the EPA has determined to
have sufficient evidence to find either is attainin g or is likely to be attaining the NAAQS.
The EPA’s decision is based on all available inform ation including the most recent 3 years of air quality monitoring data, available mod eling analysis, and any other relevant
information. 6) Modeled violation – a violation based on air disper sion modeling. 7) Recommended attainment area – an area a state or tr ibe has recommended that the EPA designate as attainment. 8) Recommended nonattainment area – an area a state or tribe has recommended that the EPA designate as nonattainment. 9) Recommended unclassifiable area – an area a state o r tribe has recommended that the EPA designate as unclassifiable. 10) Recommended unclassifiable/attainment area – an are a a state or tribe has recommended that the EPA designate as unclassifiable/attainment

. 11) Violating monitor – an ambient air monitor meeting all methods, quality assurance and siting criteria and requirements whose valid design value exceeds 75 ppb, based on data analysis conducted in accordance with Appendix T of 40 CFR part 50.5 Technical Analysis for the Linn County, Kansas Area

Proposed Designation Summary

After careful evaluation of the state’s recommendat ion and supporting information, as well as all available relevant information, the EPA intends to designate the area around the La Cygne Generating Station as unclassifiable/attainment for the 2010 SO 2 NAAQS. Specifically, the boundaries are comprised of the entirety of Linn Co unty, Kansas.

The unclassifiable/attainment designation is based on a modeling analysis that the State of Kansas provided to EPA.

Introduction

The La Cygne, Kansas area contains a stationary sou rce that according to the EPA’s Air Markets Database emitted in 2012 either more than 16,000 to ns of SO 2 or more than 2,600 tons of SO 2 and had an annual average emission rate of at least 0.45 pounds of SO 2 per one million British thermal units (lbs SO 2 /mmBTU). As of March 2, 2015, this stationary sourc e had not met the specific requirements for being “announced for reti rement.” Specifically, in 2012, the Kansas City Power & Light’s (KCP&L) La Cygne Generating St ation emitted 16,235 tons of SO 2 and
had an emissions rate of 0.36 lbs SO 2 /mmBTU. Pursuant to the March 2, 2015 court-ordered schedule, the EPA must designate the area surroundi ng the facility by July 2, 2016.

In its submission, Kansas recommended that the area surrounding the La Cygne Generating Station be designated as attainment based on an ass essment and characterization of air quality from the facility and other nearby sources which ma y have a potential impact in the area of analysis where maximum concentrations of SO 2 are expected. This assessment and characterization was performed using air dispersion modeling software, i.e., AERMOD, analyzing allowable emissions. After careful review of the state’s assessment, supporting documentation, and all available data, the EPA agre es that the area is attaining the standard, and intends to designate Linn County as unclassifiable/ attainment.

The La Cygne Generating Station is located in easte rn Kansas in the eastern portion of Linn County near the Kansas-Missouri border. As seen in Figure 1 below, the facility is located approximately 8 km east of the city of La Cygne. Th e La Cygne Generating Station includes two boiler units and no other significant emitters of S O 2 are located nearby. Also included in the figure is the state’s recommended area (the entiret y of Linn County) for its attainment designation and the EPA’s intended unclassifiable/a ttainment designation for the area.6

Figure 1: The EPA’s intended unclassifiable/attainm ent designation for Linn County, Kansas area, which includes the La Cygne Station. T he La Cygne Generating Station is located in the eastern portion of Linn County, alon g the Kansas-Missouri border.7

The discussion and analysis that follows below will reference the state’s use of the Modeling TAD, the EPA’s assessment of the state’s modeling i n accordance with the Modeling TAD, and
the factors for evaluation contained in the EPA’s M arch 20, 2015 guidance, as appropriate.

Detailed Assessment

Air Quality Data

This factor considers the SO 2 air quality monitoring data in the area surroundin g the KCP&L La Cygne facility. Since no SO 2 ambient monitors are currently located in Linn Cou nty, no monitoring data was relied upon in EPA’s proposed d esignation for this area. There was an attaining SO 2 monitor at Mine Creek in Linn County but this moni tor was re-located in 2014.

Model Selection and Modeling Components

The EPA’s Modeling TAD notes that for area designat ions under the 2010 SO 2 NAAQS, the AERMOD modeling system should be used, unless use o f an alternative model can be justified. In some instances the recommended model may be a mo del other than AERMOD, such as the BLP model for buoyant line sources. The AERMOD mode ling system contains the following components:

- AERMOD: the dispersion model

- AERMAP: the terrain processor for AERMOD

- AERMET: the meteorological data processor for AERMO D

- BPIPPRIME: the building input processor

- AERMINUTE: a pre-processor to AERMET incorporating 1-minute automated surface observation system (ASOS) wind data

- AERSURFACE: the surface characteristics processor f or AERMET

- AERSCREEN: a screening version of AERMOD

The state used AERMOD version 14134, which was the most recent version of AERMOD at the time, and a discussion of the individual components will be referenced in the corresponding discussion that follows, as appropriate.

Modeling Parameter: Rural or Urban Dispersion

The EPA’s recommended procedure for characterizing an area by prevalent land use is based on evaluating the dispersion environment within 3 km o f the facility. According to the EPA’s modeling guidelines, rural dispersion coefficients are to be used in the dispersion modeling analysis if more than 50 percent of the area within a 3 km radius of the facility is classified as rural. Conversely, if more than 50 percent of the a rea is urban, urban dispersion coefficients should be used in the modeling analysis

. When performing the modeling for the area of analys is, the state determined that it was most appropriate t o run the model in rural mode. This rural
determination was made based on the evaluation of t he land use around the facility.

Modeling Parameter: Area of Analysis (Receptor Grid )8

The EPA believes that a reasonable first step towar ds characterization of air quality in the area surrounding the La Cygne Generating Station is to d etermine the extent of the area of analysis, i.e., receptor grid. Considerations presented in th e Modeling TAD include but are not limited to:
the location of the SO 2 emission sources or facilities considered for mode ling; the extent of significant concentration gradients of nearby sourc es; and sufficient receptor coverage and density to adequately capture and resolve the model predicted maximum SO 2 concentrations. For the La Cygne Generating Station area, the state has included no other emitters of SO 2 within 10 kilometers (km) of La Cygne Generating Station. EPA has verified there are no significant SO 2 sources within 50 km of La Cygne Generating Station . The state determined that this was the appropriate distance in order to adequately charact erize air quality from the facility and other nearby sources which may have a potential impact in the area of analysis where maximum
concentrations of SO 2 are expected. The grid receptor spacing for the ar ea of analysis chosen by
the state is as follows:

• 100 meter spacing from the facility center to 1 kil ometer

• 250 meter spacing from 1 kilometers to 2.5 kilomete rs

• 500 meter spacing from 2.5 kilometers to 5 kilomete rs

• 1000 meter spacing from 5 kilometers to 10 kilomete rs

The receptor network contained 1,441 receptors and covered the eastern portion of Linn County
in Kansas.

Figure 2 shows the chosen area of analysis surround ing the La Cygne Station, as well as receptor grid for the area of analysis.

Receptors for the purposes of this designation effo rt were placed in all areas including those areas where it would not be feasible to place a mon itor. The impacts of the area’s geography and topography will be discussed later within this docu ment.9

Figure 2: Receptor Grid for the La Cygne, Kansas Ar ea of Analysis.

Modeling Parameter: Source Characterization

The state characterized the source within the area of analysis in accordance with the best practices outlined in the Modeling TAD. Specificall y, the state used actual stack heights in conjunction with allowable emissions. The state als o adequately characterized the source’s building layout and location, as well as the stack parameters, e.g., exit temperature, exit velocity, location, and diameter. Where appropriate, the AERM OD component BPIPPRIME was used to assist in addressing building downwash.

Modeling Parameter: Emissions

The EPA’s Modeling TAD notes that for the purposes of modeling to characterize air quality for use in designations, the recommended approach is to use the most recent 3 years of actual emissions data and concurrent meteorological data. However, the TAD does provide for the flexibility of using allowable emissions in the for m of the most recently permitted (referred to as PTE or allowable) emissions rate.

The EPA believes that continuous emissions monitori ng systems (CEMS) data provide acceptable historical emissions information, when i t is available, and that these data are available for many electric generating units. In the absence of CEMS data, the EPA’s Modeling TAD10

highly encourages the use of AERMOD’s hourly varyin g emissions keyword HOUREMIS or through the use of AERMOD’s variable emissions fact ors keyword EMISFACT. When choosing one of these methods, the EPA believes that detaile d throughput, operating schedules, and emissions information from the impacted source shou ld be used.

In certain instances, states and other interested p arties may find that it is more advantageous or simpler to use PTE rates as part of their modeling runs. Specifically, a facility may have recently adopted a new federally enforceable emissions limit , been subject to a federally enforceable consent decree, or implemented other federally enfo rceable mechanisms and control technologies to limit SO 2 emissions to a level that indicates compliance wit h the NAAQS. These new limits or conditions may be used in the applica tion of AERMOD. In these cases, the Modeling TAD notes that the existing SO 2 emissions inventories used for permitting or SIP planning demonstrations should contain the necessar y emissions information for designationsrelated modeling. In the event that these short-ter m emissions are not readily available, they may be calculated using the methodology in Table 8-1 of Appendix W to 40 CFR Part 51 titled, “Guideline on Air Quality Models.”

As previously noted, the state included the La Cygn e Generating Station and no other emitters of
SO 2 within 10 km in the area of analysis. This distanc e and these facilities were selected because the state believes that this area of analysis adequ ately represents the area where maximum
concentrations of SO 2 are expected and adequately includes the sources w hich might contribute to those concentrations. No other sources beyond 10 km were determined by the state to have the potential to cause significant concentration gradie nts within the area of analysis. The state has chosen to model the facility using the most recent federally enforceable limits for SO 2 . The facility in the state’s area of analysis and their associated allowable rates are summarized below.

Table 2: SO 2 Emissions based on Allowable limits from Facilitie s in the La Cygne, Kansas Area of Analysis.

Facility Name SO 2 Emissions (tons per year, based on allowables) KCP&L La Cygne Generating Station Unit 1 7,796.4

KCP&L La Cygne Generating Station Unit 2 6,780.2

Total Emissions From All Facilities in the Area of Analysis 14,576.6

The emission limits for La Cygne Generating Station were based on the installation and upgrades to emission control equipment to comply with the Be st Available Retrofit Technology (BART).
The new SO 2 controls were operational at Unit 1 in 2015 and Un it 2 in 2014.

KDHE issued an air construction permit for La Cygne Generating Station 3 on May 17, 2011 that
included 0.1 lb SO 2 /mmBTU 30-day rolling average limits for both Unit 1 and Unit 2. KDHE calculated hourly SO 2 emission rates, on a 30-day rolling average, for e ach unit based on each units’ capacity. The SO 2 permit limits were used to perform an evaluation o f these 30-day rolling

3 KDHE 1070005 KCP&L Stack replacement construction permit # C-950811

average limits to develop a critical 1-hour emissio n rate which would preserve the variability of

the hour

‐ to

‐ hour emission profile with scrubber controls, yet b e conservative so as to protect the ambient air quality standard for the attainment dem onstration. KDHE used the EPA Guidance for 1

‐ Hour SO 2 Nonattainment Area State Implementation Plan Submi ssions memorandum dated April 23, 2014, as guidance in establishing these c ritical 1-hour emission rates. Based on that guidance, KDHE used CEMS data for La Cygne Unit 1. For Unit 2, KDHE reviewed a similar KCP&L emission unit (KCP&L Iatan Unit 1) with simil ar control technology to establish an appropriate critical 1-hour emission rate.

The steps below outline the approach KDHE used to d etermine the ratio that was applied to the 30-day average emission limit:

1. Collect 5

‐ years of suitable hourly CEMS data.
2. Calculate the 99 th percentile 1

‐ hr emission rate over the 5

‐ year period.
3. Calculate the 99 th percentile 30

‐ day rolling average over the 5

‐ year period.
4. Calculate the ratio of the 99 th percentile 30

‐ day rolling average from Step 3 to the 99 th percentile 1

‐ hr value calculated from Step 2.
5. Apply that calculated ratio to the La Cygne Unit 1 and Unit 2 30

‐ day rolling average
emission rate.

Based on the procedure outlined above, the ratios f or Unit 1 and Unit 2 were approximately 0.522 and 0.475, respectively. The average of the t wo ratios, 0.497, was divided into the 30

‐ day average rolling limits for Unit 1 and Unit 2 to com pute the critical hourly SO 2 emission rates used in the modeling analysis. The critical hourly emission rates used in the modeling are shown
in Table 3.

Table 3: Modeled SO 2 Emissions based on 30-day average emissions limits for Unit 1 and

Unit 2 in the Linn County, Kansas Area of Analysis

Company ID Unit Name SO 2 Emissions (lb/hr), (based on 30-day emission limit variability analysis)

KCP&L Unit 1 1,780

KCP&L Unit 2 1,548

Modeling Parameter: Meteorology and Surface Charact eristics

The most recent 3 years of meteorological data (con current with the most recent 3 years of emissions data) should be used in designations effo rts. As noted in the Modeling TAD, the selection of data should be based on spatial and cl imatological (temporal) representativeness. The representativeness of the data are based on: 1) the proximity of the meteorological monitoring site to the area under consideration, 2) the complexity of terrain, 3) the exposure of the meteorological site, and 4) the period of time during which data are collected. Sources of meteorological data include National Weather Servic e (NWS) stations, site-specific or onsite12

data, and other sources such as universities, Feder al Aviation Administration (FAA), and military stations.

For the La Cygne Generating Station area of analysi s, surface meteorology from Topeka, Kansas, approximately 160 km to the northwest, and coincident upper air observations from the NWS station in Topeka, Kansas were selected as best representative of meteorological conditions within the area of analysis. The locatio n of the meteorological surface and upper air stations are shown in Figure 3.

The state used AERSURFACE version 13016 using data from the NWS station in Topeka, Kansas (located at 40.06N, 95.60W) to estimate the surface characteristics of the area of analysis. The state also estimated values for albed o (the fraction of solar energy reflected from the earth back into space), the Bowen ratio (the me thod generally used to calculate heat lost or heat gained in a substance), and the surface roughn ess (sometimes referred to as “Zo”). In Figure 3, the location of the Topeka, Kansas NWS station i s shown relative to the La Cygne area of analysis.

Figure 3: La Cygne Generating Station Area of Analy sis and the Topeka, Kansas NWS site used for surface and upper air meteorology.

As part of its recommendation, the state provided t he 3-year surface wind rose for Topeka, Kansas. In Figure 4, the frequency and magnitude of wind speed and direction are defined in13

terms of from where the wind is blowing. Winds at t he Topeka, Kansas location are most often
out of the south but there is both a southeast and northwest component.

Figure 4: Topeka, Kansas Cumulative Annual Wind Ros e for Years 2012 – 2014

Meteorological data from the Topeka, KS surface and upper air stations were used in generating AERMOD-ready files with the AERMET processor. The o utput meteorological data created by the AERMET processor is suitable for being applied with AERMOD input files for AERMOD modeling runs. The state followed the methodology a nd settings presented in EPA’s Modeling TAD in the processing of the raw meteorological dat a into an AERMOD-ready format and used AERSURFACE to best represent surface characteristic s.

Hourly surface meteorological data records are read by AERMET and include all the necessary elements for data processing. However, wind data ta ken at hourly intervals may not always portray wind conditions for the entire hour, which can be variable in nature. Hourly wind data may also be overly prone to indicate calm condition s, which are not modeled by AERMOD. In order to better represent actual wind conditions at the meteorological tower, wind data of one minute duration was provided from the same instrume nt tower but in a different formatted file to14

be processed by a separate preprocessor, AERMINUTE. These data were subsequently integrated into the AERMET processing to produce fi nal hourly wind records of AERMODready meteorological data that better estimate actu al hourly average conditions and that are less prone to over-report calm wind conditions. This all ows AERMOD to apply more hours of meteorology to modeled inputs and therefore produce a more complete set of concentration estimates. As a guard against excessively high conc entrations that could be produced by AERMOD in very light wind conditions, the state set a minimum threshold of 0.5 meters per second in processing meteorological data for use in AERMOD. This approach is consistent with a March 2013 EPA memo titled, “Use of ASOS meteorol ogical data in AERMOD dispersion Modeling.” In setting this threshold, no wind speed s lower than this value would be used for determining concentrations. This threshold was spec ifically applied to the one minute wind data.

Modeling Parameter: Geography and Terrain

The terrain in the area of analysis is best describ ed as relatively flat. To account for these terrain changes, the AERMAP terrain program within AERMOD w as used to specify terrain elevations for all the receptors. The source of the elevation data incorporated into the model is from the National Elevation Dataset (NED). The NED data avai lable on-line in 1/3 arc-second spacing from the US Geological Survey was used in the model ing analysis.

Modeling Parameter: Background Concentrations of SO 2

The Modeling TAD offers two mechanisms for characte rizing background concentrations of SO 2 that are ultimately added to the modeled design val ues: 1) a “first tier” approach, based on monitored design values, or 2) a temporally varying approach, based on the 99 th percentile monitored concentrations by hour of day and season or month. For the La Cygne Generating Station area of analysis, the state used the “first tier” approach chose a background concentration to be 18.01 micrograms per cubic meter ( μ g/m 3 ), or 7 ppb, 4 and that value was incorporated into
the final AERMOD results. The state indicated that this background concentration was the design value for the Mine Creek monitor for the per iod 2011-2013. The Mine Creek SO 2 monitor was located in Linn County, Kansas, on County Rd 11 03, 0.7 miles south of Hwy K-52, approximately 32 km southwest of La Cygne Generatin g Station. This SO 2 monitor was
relocated in 2014 to a location outside of Linn Cou nty.

Summary of Modeling Results

The AERMOD modeling parameters for the La Cygne Gen erating Station area of analysis are
summarized below in Table 4.

Table 4: AERMOD Modeling Parameters for the La Cygn e Generating Station Area of Analysis

4 The conversion factor for SO 2 (at the standard conditions applied in the ambient SO 2 reference method) is 1ppb = approximately 2.62 μ g/m 3

.15 La Cygne Area of Analysis

AERMOD Version 14134 Dispersion Characteristics Rural

Modeled Sources 1

Modeled Stacks 2

Modeled Structures 23

Modeled Fencelines 0 Total receptors 1,441 Emissions Type Allowable

Emissions Years Allowable Meteorology Years 2012-2014 Surface Meteorology Station Topeka, Kansas Upper Air Meteorology Station Topeka, Kansas Methodology for Calculating Background SO 2 Concentration 1 st tier Calculated Background SO 2 Concentration 18.01 μ g/m 3

The results presented below in Table 5 show the mag nitude and geographic location of the highest predicted modeled concentration based on al lowable emissions. Two modeling scenarios
were modeled:

Scenario 1 – High Load -- High load emission rate, temperature and flow rate;

Scenario 2 – Low Load -- High load emission rate, l ow load temperature and flow rate (deemed “worst case”)

Table 5: Maximum Predicted 99th Percentile 1-Hour S O 2 Concentration in the La Cygne Generating Station Area of Analysis Based on Allowa ble Emissions

Averaging
Period Modeling

Scenario Data Period Receptor Location SO 2 Concentration ( μ g/m 3 )
UTM/
Latitude UTM/

Longitude Modeled

(including background) NAAQS
99th Percentile
1-Hour Average High Load
2012-2014 354381 4244974 126.05 196.5*

Low Load (“worst case”) 2012-2014 354565 4246724 137.82 196. 5* *Equivalent to the 2010 SO 2 NAAQS set at 75 ppb

The state’s modeling of a “worst case” scenario ind icates that the predicted 99 th percentile 1-hour average concentration within the chosen modeling do main is 137.82 μ g/m 3 , or 53 ppb. This

modeled concentration included the background concentration of SO 2 and is based on allowable16

emissions from the facility. Figure 5 below was inc luded as part of the state’s recommendation and indicates that the predicted value occurred nor thwest of the facility.

Figure 5: Maximum Predicted 99 th Percentile 1-Hour SO 2 Concentrations (120 μ g/m 3 without background) in the La Cygne Generating Station Area of Analysis Based on
Allowable Emissions.

Jurisdictional Boundaries:

Once the geographic area of analysis associated wit h the La Cygne Generating Station and background concentration is determined, existing ju risdictional boundaries are considered for the purpose of informing our intended unclassifiable/at tainment area, specifically with respect to clearly defined legal boundaries.

The EPA has confirmed that except for the La Cygne Generating Station, which has been modeled to show compliance with the NAAQS, there ar e no sources within Linn County or any of its neighboring counties that would be likely ca ndidates for future characterization under the DRR. Furthermore, there are no sources in Linn Coun ty or any of its neighboring counties that emit above 100 tpy of SO 2 , according to the 2011 NEI. Therefore, the EPA doe s not believe that sources within Linn County or its neighboring count ies have the potential to cause or contribute to a violation of the NAAQS within Linn County.17

The EPA believes that our intended unclassifiable/a ttainment area, consisting of the entirety of Linn County, Kansas are comprised of clearly define d legal boundaries, and we find these boundaries to be a suitably clear basis for definin g our intended unclassifiable/attainment area.

Other Relevant Information

EPA did not receive 3 rd party information pertaining to the analysis of th e 1-hr SO 2 impacts for the La Cygne Generating Station.

Conclusion

After careful evaluation of the state’s recommendat ion and supporting information, as well as all available relevant information, the EPA intends to designate the area around the La Cygne Generating Station as unclassifiable/attainment for the 2010 SO 2 NAAQS. Specifically, the boundaries are comprised of the entirety of Linn Co unty, Kansas.

The unclassifiable/attainment designation is based on modeling analysis that the State of Kansas provided to EPA and our assessment that no other so urces in Linn County or its neighbors are likely to cause or contribute to a violation of the NAAQS within Linn County. The modeling uses federally enforceable allowable emissions to s how attainment, based on new emission limits put in place in 2014 and 2015. The modeling submitt ed by the state of Kansas followed the recommended EPA modeling TAD for designation purpos es.

At this time, our intended designations for the sta te only apply to this area and the other areas presented in this technical support document. Consi stent with the conditions in the March 2, 2015, consent decree, the EPA will evaluate and des ignate all remaining undesignated areas in Kansas by either December 31, 2017, or December 31, 2020.18 Technical Analysis for the Wyandotte County, KS Are a

Proposed Designation Summary

After careful evaluation of the state’s recommendat ion and supporting information, as well as all available relevant information, the EPA intends to designate the Nearman Station area as
unclassifiable for the 2010 SO 2 NAAQS. Specifically, the boundaries are comprised of the entirety of Wyandotte County, Kansas.

EPA’s proposed designation is based on the modeling analysis that the state of Kansas provided
to EPA.

Introduction

The Kansas City, Kansas area, located in Wyandotte County contains a stationary source that according to the EPA’s Air Markets Database emitted in 2012 either more than 16,000 tons of
SO 2 or more than 2,600 tons of SO 2 and had an annual average emission rate of at leas t 0.45 pounds of SO 2 per one million British thermal units (lbs SO 2 /mmBTU). As of March 2, 2015, this stationary source had not met the specific req uirements for being “announced for retirement.” Specifically, in 2012, the Kansas City , Kansas’ Board of Public Utilities (BPU) Nearman Creek (Nearman) Station emitted 4,612 tons of SO 2 and had an emissions rate of 0.64
lbs SO 2 /mmBTU. Pursuant to the March 2, 2015 court-ordered schedule, the EPA must designate the area surrounding the facility by July 2, 2016.

In its submission, Kansas recommended the Nearman S tation area, specifically the entirety of Wyandotte County, be designated as unclassifiable/a ttainment based on an assessment and characterization of air quality from the facility a nd other nearby sources which may have a potential impact in the area of analysis where maxi mum concentrations of SO 2 are expected. This assessment and characterization was performed using air dispersion modeling software, i.e., AERMOD, analyzing actual emissions. After careful r eview of the state’s assessment, supporting documentation, and all available data, the EPA disa grees with the state’s recommendation for the area, and intends to designate the area as unclassi fiable. Specifically, our intended unclassifiable area consists of the entirety of Wyandotte County.

The Nearman Station is located in eastern Kansas in the northeast portion of Wyandotte County. As seen in Figure 6, the facility is located approx imately 10 km north of the center of Kansas City, Kansas. The Nearman Station lies next to the Missouri River on the Kansas side of the Kansas-Missouri border. No other significant emitte rs of SO 2 are located nearby within Wyandotte County but Kansas identified 4 other sign ificant sources of SO 2 in nearby Jackson County in the State of Missouri. Also included in F igure 6 are these four nearby SO 2 emitters,
the state’s recommended area for its unclassifiable /attainment designation (entirety of Wyandotte County), and the EPA’s intended unclassifiable desi gnation for the area (also the entirety of Wyandotte County)19

Figure 6: The EPA’s intended unclassifiable designa tion for Wyandotte County, Kansas
area which includes the Nearman Creek Station. The Nearman Creek Station is located in the northeast portion of Wyandotte County. The blue points represent other modeled
sources of SO 2 in the area of analysis.

The discussion and analysis that follows below will reference the state’s use of the Modeling TAD, the EPA’s assessment of the state’s modeling i n accordance with the Modeling TAD, and
the factors for evaluation contained in the EPA’s M arch 20, 2015 guidance, as appropriate.

Detailed Assessment

Air Quality Data

This factor considers the SO 2 air quality monitoring data in the area surroundin g the BPU Nearman Creek facility. KDHE included in its recomm ended designation documentation that the JFK NCore monitoring site is located 5 miles southe ast of the Kansas City BPU – Nearman site
and that the recorded concentrations were below the NAAQS. However, since it is not clear if this monitor is located in an area that represents peak concentrations of SO 2 from BPU – Nearman, the data from this monitor is not being re lied upon in the proposed designation for this

area.

Model Selection and Modeling Components20

The EPA’s Modeling TAD notes that for area designat ions under the 2010 SO 2 NAAQS, the AERMOD modeling system should be used, unless use o f an alternative model can be justified. In some instances the recommended model may be a mo del other than AERMOD, such as the BLP model for buoyant line sources. The AERMOD mode ling system contains the following components:

- AERMOD: the dispersion model

- AERMAP: the terrain processor for AERMOD

- AERMET: the meteorological data processor for AERMO D

- BPIPPRIME: the building input processor

- AERMINUTE: a pre-processor to AERMET incorporating 1-minute automated surface observation system (ASOS) wind data

- AERSURFACE: the surface characteristics processor f or AERMET

- AERSCREEN: a screening version of AERMOD

The state used AERMOD version 14134, which was the most recent version of AERMOD at the time, and a discussion of the individual components will be referenced in the corresponding discussion that follows, as appropriate.

Modeling Parameter: Rural or Urban Dispersion

The EPA’s recommended procedure for characterizing an area by prevalent land use is based on evaluating the dispersion environment with 3 km of the facility. According to the EPA’s modeling guidelines, rural dispersion coefficients are to be used in the dispersion modeling analysis if more than 50 percent of the area within a 3 km radius of the facility is classified as rural. Conversely, if more than 50 percent of the a rea is urban, urban dispersion coefficients should be used in the modeling analysis. When performing the modeling for the area of analys is, the state determined that it was most appropriate t o run the model in urban mode. The urban determination was made by the evaluation of land us e and population density analysis. While the Nearman Station lies in a sparsely populated area o f Wyandotte County north of the center of Kansas City, KS, some of the other significant sour ces modeled in the demonstration are located in the urban Kansas City metropolitan area. The sta te of Kansas modeled all sources using the urban option.

Modeling Parameter: Area of Analysis (Receptor Grid )

The EPA believes that a reasonable first step towar ds characterization of air quality in the area surrounding the Nearman Station is to determine the extent of the area of analysis, i.e., receptor grid. Considerations presented in the Modeling TAD include but are not limited to: the location
of the SO 2 emission sources or facilities considered for mode ling; the extent of significant concentration gradients of nearby sources; and suff icient receptor coverage and density to adequately capture and resolve the model predicted maximum SO 2 concentrations. For the Nearman Station area, the state has included four o ther emitters of SO 2 within 50 kilometers (km) of the Nearman Station in any direction. The s tate determined that this was the appropriate distance in order to adequately characterize air qu ality from the facility and other nearby sources which may have a potential impact in the area of an alysis where maximum concentrations of SO 2 are expected. The grid receptor spacing for the are a of analysis chosen by the state is as follows:21

• 100 meter spacing from center of Nearman Station to 5 kilometers

• 500 meter spacing from outside of 5 kilometers and within Wyandotte County

The receptor network contained 6,582 receptors and covered all of Wyandotte County. Figure 7 shows the chosen area of analysis surrounding the N earman Station, as well as the receptor grid for the area of analysis. No receptors were placed on the Missouri side of the Kansas-Missouri border. Therefore, only impacts to the south of Nea rman Station can be evaluated. Since there were no receptors placed in Missouri, the receptor grid is inconsistent with the Modeling TAD, as receptors should be placed in areas where it wou ld be feasible to place a monitor and record ambient impacts. It appears that it would be feasib le to place monitors to record ambient impacts in the adjacent counties of Platte, Clay and Jackso n in Missouri.

Figure 7: Receptor Grid for the Nearman Station Are a of Analysis. Receptors encompass all of Wyandotte County. The location of Nearman St ation is represented by the green dot. Image courtesy of Kansas Department of Health and E nvironment.

Modeling Parameter: Source Characterization22

Except as discussed elsewhere in this document, the state characterized the source within the area of analysis in accordance with the best practi ces outlined in the Modeling TAD. Specifically, the state used actual stack heights i n conjunction with actual emissions. The state initially did not adequately characterize the sourc e’s building layout and location, as inputs in to BPIPPRIME appeared to be incorrect in relation to t he stack. The state corrected the locations in a prior run but left the stack structure for Nearma n Station as a building structure input, which is not correct. EPA believes it is very important in a BPIP run to have the structures aligned and defined correctly. EPA is unsure of the overall con centration impact of having the stack remain as a building structure within BPIP.

Modeling Parameter: Emissions

The EPA’s Modeling TAD notes that for the purposes of modeling to characterize air quality for use in designations, the recommended approach is to use the most recent 3 years of actual emissions data and concurrent meteorological data. However, the TAD does provide for the flexibility of using allowable emissions in the for m of the most recently permitted (referred to as PTE or allowable) emissions rate.

The EPA believes that continuous emissions monitori ng systems (CEMS) data provide acceptable historical emissions information, when i t is available, and that these data are available for many electric generating units. In the absence of CEMS data, the EPA’s Modeling TAD highly encourages the use of AERMOD’s hourly varyin g emissions keyword HOUREMIS or through the use of AERMOD’s variable emissions fact ors keyword EMISFACT. When choosing one of these methods, the EPA believes that detaile d throughput, operating schedules, and emissions information from the impacted source shou ld be used.

In certain instances, states and other interested p arties may find that it is more advantageous or simpler to use PTE rates as part of their modeling runs. Specifically, a facility may have recently adopted a new federally enforceable emissions limit , been subject to a federally enforceable consent decree, or implemented other federally enfo rceable mechanisms and control technologies to limit SO 2 emissions to a level that indicates compliance wit h the NAAQS. These new limits or conditions may be used in the applica tion of AERMOD. In these cases, the Modeling TAD notes that the existing SO 2 emissions inventories used for permitting or SIP planning demonstrations should contain the necessar y emissions information for designationsrelated modeling. In the event that these short-ter m emissions are not readily available, they may be calculated using the methodology in Table 8-1 of Appendix W to 40 CFR Part 51 titled, “Guideline on Air Quality Models.”

As previously noted, the state included the Nearman Station and four other emitters of SO 2 within 50 km in the area of analysis. The state sel ected this distance and facilities because the state believes that this area of analysis adequatel y includes the sources which might contribute to
SO 2 concentrations within Wyandotte County. For this a rea of analysis, the state has opted to use a hybrid approach, where emissions from certain fac ilities are expressed as actual emissions, and those from other facilities are expressed as allowa ble rates.23

For the Nearman Station area of analysis, the state included annual actual SO 2 emissions
between 2012 and 2014. This information is summariz ed in Table 6 and the emissions data was
obtained from CEMS from the EPA’s Clean Air Markets Division.

Table 6: Actual SO 2 Emissions Between 2012 – 2014 from Facilities in t he Wyandotte County, Kansas Area of Analysis

Facility Name SO 2 Emissions (tons per year)

2012 2013 2014
BPU Nearman Creek Unit 1 4,611.8 4,927.9 5,330.9
Total Emissions From All Facilities that used actua l emissions in the Area of Analysis 4,611.8 4,927.9 5 ,330.9

For the following facilities in the area of analysi s, the state has chosen to model the facilities using the future and not yet enforceable allowable limits for SO 2 . The facilities in the state’s area of analysis and their associated future allowable r ates are summarized below in Table 7. Of note, the modeled allowable rate at the Veolia Energy Cen ter, the Sibley Station, and Hawthorn Station are to be in place and federally enforceabl e by January 1, 2017 per State of Missouri Rule 10 CSR 10-6.261, which is past the July 2, 2016 des ignation deadline. Because the modeling analysis used emission rates that will not be effec tive by the designation date 5 and therefore cannot be credited to inform a final designation de cision, EPA can’t rely upon the modeling analysis provided by the state to inform EPA’s desi gnation recommendation for the Nearman
Station area.

Table 7: SO 2 Emissions based on Future Allowable Limits from Fa cilities in the Wyandotte County, Kansas Area of Analysis

Facility Name SO 2 Emissions (tons per year, based on future allowable emissions)
Veolia Energy Unit 1 2.5 *

Veolia Energy Unit 2 1,540.9*

Veolia Energy Unit 3 2.5*
Independence Power & Light – Missouri City Unit 5 2,986.7

Independence Power & Light – Missouri City Unit 6 1.3
Kansas City Power & Light – Sibley Station Unit 5A 6,430.6*
Kansas City Power & Light – Sibley Station Unit 5B 6,337.9*
Kansas City Power & Light – Sibley Station Unit 5C 46,568.2*

Kansas City Power & Light – Hawthorn Station Unit 6 3,438.3*

Total Emissions From All Facilities that used allow able limits in the Area of Analysis 67,308.9

*not federally enforceable by July 2, 2016

5 See Attachment 2 of the March 20, 2015 document ti tled “Updated Guidance for Area Designations for th e 2010 Primary Sulfur Dioxide National Ambient Air Quality Standard” from Stephen D. Page, Director of the Of fice of Air Quality Planning and Standards.24

EPA notes that the BPU Quindaro Power Plant ceased burning coal and began solely burning natural gas in April 2015. Therefore, although the facility emitted significant amounts of SO 2 from 2012-2014, the facility no longer has signific ant SO 2 emissions. The SO 2 emissions from the combustion of natural gas are assumed to be inc luded in the background concentration. EPA further notes that Blue Valley Station has three co al fired boilers and is required, in Missouri Rule 10 CSR 10-6.261, to switch to natural gas by J anuary 1, 2017. In addition, Blue Valley is subject to the boiler MACT and has indicated to Mis souri they will switch to natural gas by January 21, 2016, well ahead of the July 2, 2016, d esignation date, therefore this facility was not included in the modeling analysis. It is noted that Missouri Rule 10 CSR 10-6.261 has an initial compliance date after July 2, 2016, and has not yet been adopted into Missouri’s SIP. Blue Valley has stated it intends to complete the fuel s witch before July 2, 2016, but this requirement is not contained in a federally enforceable documen t, thus EPA is not accepting the KDHE attainment modeling that relies upon this fuel swit ch assumption.

Modeling Parameter: Meteorology and Surface Charact eristics

The most recent 3 years of meteorological data (con current with the most recent 3 years of emissions data) should be used in designations effo rts. As noted in the Modeling TAD, the selection of data should be based on spatial and cl imatological (temporal) representativeness. The representativeness of the data are based on: 1) the proximity of the meteorological monitoring site to the area under consideration, 2) the complexity of terrain, 3) the exposure of the meteorological site, and 4) the period of time during which data are collected. Sources of meteorological data include National Weather Servic e (NWS) stations, site-specific or onsite data, and other sources such as universities, Feder al Aviation Administration (FAA), and military stations.

For the Kansas City, Kansas area of analysis, surfa ce meteorology from the Charles B. Wheeler Airport site located in downtown Kansas City, Misso uri (KMKC) approximately 10 km to the southeast, and coincident upper air observations fr om the NWS station in Topeka, Kansas, approximately 100 km to the west were selected as b est representative of meteorological conditions within the area of analysis. The locatio n of the meteorological surface and upper air stations are shown in Figure 8.

The state used AERSURFACE version 13016 using data from the NWS station KMKC (39.12N, 94.59W) to estimate the surface characteristics of the area of analysis. The state estimated values for 12 spatial sectors out to 1 km at a seasonal te mporal resolution for dry, wet, or average conditions for each respective year. The state also estimated values for albedo (the fraction of solar energy reflected from the earth back into spa ce), the Bowen ratio (the method generally used to calculate heat lost or heat gained in a sub stance), and the surface roughness (sometimes referred to as “Zo”). In Figure 8, the location of the Kansas City, MO surface meteorological station and the Topeka, KS upper air station are sh own relative to the Nearman Station area of analysis.25

Figure 8: Nearman Station Area of Analysis and the Downtown Kansas City, MO NWS site used for surface meteorology, the Topeka, Kansas NW S site used for upper air meteorology.

As part of its recommendation, the state provided t he 3-year surface wind rose for Kansas City, Missouri. In Figure 9, the frequency and magnitude of wind speed and direction are defined in terms of from where the wind is blowing. Winds at t he Kansas City, MO location are predominately out of south-southwest, and a seconda ry component from the northwest.26

Figure 9: Charles B. Wheeler Airport site located i n downtown Kansas City, Missouri
Cumulative Annual Wind Rose for Years 2012 – 2014

Meteorological data from the Kansas City, MO surfac e and Topeka, KS upper air stations were used in generating AERMOD-ready files with the AERM ET processor. The output meteorological data created by the AERMET processor is suitable for being applied with AERMOD input files for AERMOD modeling runs. The st ate followed the methodology and settings presented in EPA’s Modeling TAD in the pro cessing of the raw meteorological data into an AERMOD-ready format and used AERSURFACE to best represent surface characteristics.

Hourly surface meteorological data records are read by AERMET and include all the necessary elements for data processing. However, wind data ta ken at hourly intervals may not always portray wind conditions for the entire hour, which can be variable in nature. Hourly wind data may also be overly prone to indicate calm condition s, which are not modeled by AERMOD. In order to better represent actual wind conditions at the meteorological tower, wind data of one minute duration was provided from the same instrume nt tower but in a different formatted file to be processed by a separate preprocessor, AERMINUTE. These data were subsequently integrated into the AERMET processing to produce fi nal hourly wind records of AERMODready meteorological data that better estimate actu al hourly average conditions and that are less prone to over-report calm wind conditions. This all ows AERMOD to apply more hours of meteorology to modeled inputs and therefore produce a more complete set of concentration estimates. As a guard against excessively high conc entrations that could be produced by AERMOD in very light wind conditions, the state set a minimum threshold of 0.5 meters per second in processing meteorological data for use in AERMOD. This approach is consistent with a March 2013 EPA memo titled, “Use of ASOS meteorol ogical data in AERMOD dispersion27

Modeling.” In setting this threshold, no wind speed s lower than this value would be used for determining concentrations. This threshold was spec ifically applied to the one minute wind data.

Modeling Parameter: Geography and Terrain

The terrain in the area of analysis is best describ ed as relatively flat. To account for these terrain changes, the AERMAP terrain program within AERMOD w as used to specify terrain elevations for all the receptors. The source of the elevation data incorporated into the model is from the National Elevation Dataset (NED). The NED data avai lable on-line in 1/3 arc-second spacing from the US Geological Survey was used in the model ing analysis.

Modeling Parameter: Background Concentrations of SO 2

The Modeling TAD offers two mechanisms for characte rizing background concentrations of SO 2 that are ultimately added to the modeled design val ues: 1) a “first tier” approach, based on monitored design values, or 2) a temporally varying approach, based on the 99 th percentile monitored concentrations by hour of day and season or month. For the Nearman Station area of analysis, the state used the first tier approach an d chose a background concentration to be 33.57 micrograms per cubic meter ( μ g/m 3 ), or 13 ppb, 6 and that value was incorporated into the final AERMOD results. This background value was from the JFK monitor located in Wyandotte County, Kansas.

Summary of Modeling Results

The AERMOD modeling parameters for the Nearman Stat ion area of analysis are summarized
below in Table 8.

Table 8: AERMOD Modeling Parameters for the Nearman Creek Area of Analysis Nearman Creek Station Area of Analysis

AERMOD Version 14134 Dispersion Characteristics urban

Modeled Sources 5

Modeled Stacks 1

Modeled Structures 14

Modeled Fencelines 0 Total receptors 6,582 Emissions Type Actual and Future Allowable

Emissions Years 2012-2014 for actual, January 1, 2017 rule for future
allowable limits

6 The conversion factor for SO 2 (at the standard conditions applied in the ambient SO 2 reference method) is 1ppb = approximately 2.62 μ g/m 3

.28 Meteorology Years 2012-2014

Surface Meteorology Station Kansas City, Missouri – Charles B. Wheeler Airport Upper Air Meteorology Station Topeka, Kansas Methodology for Calculating Background SO 2 Concentration 1 st tier Calculated Background SO 2 Concentration 33.57 μ g/m 3

The results presented below in Table 9 show the mag nitude and geographic location of the highest predicted modeled concentrations based on t he mix of actual and future allowable
emissions.

Table 9: Maximum Predicted 99th Percentile 1-Hour S O 2 Concentration in the Wyandotte County, Kansas Area of Analysis Based on Actual and Future Allowab le Emissions

Averaging Period Data Period Receptor Location SO 2 Concentration ( μ g/m 3 )

UTM/Latitude UTM/Longitude Modeled (including background) NAAQS
99th Percentile 1-Hour Average 2012-2014 353873 4334994 193.17 196. 5* *Equivalent to the 2010 SO 2 NAAQS set at 75 ppb

The state’s modeling indicates that the predicted 9 9 th percentile 1-hour average concentration within the chosen modeling domain is 193.17 μ g/m 3 , or 73.7 ppb, indicating 1-hr SO 2 NAAQS attainment for all of Wyandotte County. This modele d concentration included the background

concentration of SO 2 and is based on actual emissions from the BPU faci lity and future
allowable emissions from other facilities. EPA dete rmined this value based on the modeling input files provided by KDHE. Figure 10 below indic ates that the predicted maximum value occurred just to the southeast of the BPU facility. As previously mentioned, no receptors were placed in nearby Missouri Counties, where impacts f rom the Nearman Station emissions may

occur.29

Figure 10: Maximum Predicted 99 th Percentile 1-Hour SO 2 Concentrations (159.60 μ g/m 3 without background) in the Wyandotte County, Kansas Area of Analysis Ba sed on a mix of
Actual Emissions and Future Allowable emissions. No te that receptors, and thus modeled predictions, are only placed in Wyandotte County. I mpacts in the State of Missouri cannot

be evaluated.

Jurisdictional Boundaries:

Once the geographic area of analysis associated wit h the Nearman Station, other nearby sources, and background concentration is determined, existin g jurisdictional boundaries are considered for the purpose of informing our intended unclassif iable area, specifically with respect to clearly defined legal boundaries.

As mentioned previously, EPA observes that other si gnificant sources within the area of analysis for the Nearman Creek Station were modeled using fu ture allowable emissions limits that will not be federally enforceable by July 2, 2016. Also, another significant source, the Independence Power & Light Blue Valley Station located within th e area of analysis was not included in the modeling analysis. Thus, EPA believes the state’s m odeled evaluation of SO 2 concentrations for Wyandotte County, Kansas does not adequately charac terize all the emissions potentially impacting the Nearman Station area of analysis. The refore, EPA believes that our intended unclassifiable area, consisting of the entirety of Wyandotte County, is comprised of clearly30

defined legal boundaries, and we find these boundar ies to be a suitably clear basis for defining
our intended unclassifiable area.

Other Relevant Information

The EPA received air dispersion modeling results fr om Sierra Club, asserting that SO 2 emissions from the Nearman Station, when considered with othe r local sources, are contributing to a violation of the NAAQS within or around the existin g Jackson County nonattainment area. The modeling Sierra Club provided was for a separate co nsent decree source and separate area, the Sibley Station in Missouri, in which the Nearman St ation (approximately 50 km away from the Sibley Station) was included as an interactive sour ce. Because the Sierra Club modeling contained Nearman, EPA evaluated Sierra Club modeli ng with respect to this designation area around Nearman and separately the area around Sible y. Two Sierra Club modeling demonstrations were provided, one using actual emis sions and another using allowable emissions. Both Sierra Club modeling scenarios show violations of the 1-hr SO 2 NAAQS, although the Sierra Club’s modeling scenario using actual emissions indicate modeled violations both in and around the Veolia Energy Center.

Although Sierra Club submitted modeling based on al lowable emission rates, we have concerns that the allowable modeling, as presented, does not represent true SO 2 concentrations in the area, and we are unable to reliably determine whether the area is in attainment or nonattainment based on the allowable modeling. While the modeling TAD does not preclude the use of allowable emissions, for designations allowable emissions are generally used in the case where controls and limits have been recently established, and not to establish actual SO 2 concentrations a monitor might record. 7

The Sierra Club modeling for the Sibley Station use d a receptor grid out to 50 km and extending the modeling domain out to 50 km allowed for recept ors to be placed in Wyandotte County, Kansas and brought the Nearman Station, as mentione d above, into the Sibley Station analysis as a very distant interactive source. While a 50 km re ceptor domain is permitted in the AERMOD modeling system, this Sierra Club grid also include s receptors in an existing 1-hr SO 2 nonattainment area in Jackson County MO. As seen in Figure 11, the existing nonattainment area in Jackson County, Missouri is an area approximatel y 13 km to the southeast of Nearman and 40 km to the southwest of the Sibley Station.

7 Designations are intended to address current actual air quality (i.e., modeling simulates a monitor), and, thus, are unlike attainment plan modeling, which mu st provide assurances that attainment will occur. F or the purposes of designations, modeling can be used as a surrogate to ambient monitoring to characteriz e air quality for the designations process. The EPA r ecommends modeling the most recent 3 years of actua l emissions. Emissions Input section (Page 9) http://www3.epa.gov/airquality/sulfurdioxide/pdfs/S O2ModelingTAD.pdf31

Figure 11: Existing Jackson County Missouri SO 2 Nonattainment area (hashed in magenta)
with Kansas and Nearman to the West.

The Jackson County, Missouri nonattainment area is being addressed under a separate nonattainment SIP that will require a demonstration that the area demonstrates and maintains compliance with the NAAQS. MDNR submitted the nonat tainment SIP for Jackson County to EPA on October 9, 2015, and the agency is currently reviewing this SIP. In establishing the current Jackson County nonattainment area, the emis sions from Nearman were considered and it

was determined at that time Nearman contributions d id not warrant an expanded nonattainment area that would include the Nearman source. Althoug h Sierra Club asserts in their comments significant contributions from Nearman, it is uncle ar from the Sierra Club modeling analysis what the actual Nearman source contributions are, o r where they occur, when predicted
exceedances occur in the nonattainment area and the area south of the Sibley Station. Without further description and analysis of both when and w here Nearman contributions occur we cannot determine if Nearman should be included in a separa te nonattainment area. What is clear from the Sierra Club analysis is no modeled violations a ppear to exist directly surrounding the Nearman facility.

EPA notes that the Sierra Club provided a table wit h maximum 99 th percentile modeled impacts and individual facility impacts as well as impacts from all facilities combined, but it does not
address individual contribution at the time of mode led exceedances. The Sierra Club modeling provided a contribution summary in their modeling r eport, and the summary indicates that the32

area surrounding the Nearman Station, when evaluate d alone, complies with the 1-hr SO 2 NAAQS. However, when actual emissions from Veolia E nergy Center are included, the NAAQS is exceeded around the Veolia Energy Center. Overal l, the Sierra Club model results for the area
around the Nearman Station are similar to those fro m the State of Kansas’ modeling and show NAAQS attainment in Wyandotte County.

EPA believes the Sierra Club modeling meets the req uirements of the EPA modeling TAD in terms of inputs and model settings, as EPA previous ly stated. However sources within the existing nonattainment area for the 2010 1-hour SO 2 NAAQS have been evaluated and a plan has been developed by the states of Kansas and Missouri which has been submitted for EPA action. At this time, EPA believes that the Sierra Club did not provide enough information to EPA to determine Nearman’s impact on modeled violations bo th within and outside of the existing Jackson County nonattainment area. Because EPA does not have the maximum daily contributions files (MAXDCONT) as part of the AERMO D modeling outputs from Sierra Club, EPA can’t directly determine Sierra Club’s assertio n that Nearman Station actually does contribute to exceeding concentrations during those periods of modeled violations around the Veolia Energy Center. For these reasons, EPA is not relying upon the Sierra Club modeling for the designation determination in the Nearman Statio n area.

Conclusion

After careful evaluation of the state’s recommendat ion and supporting information, as well as all available relevant information, the EPA intends to designate the Nearman Station area as
unclassifiable for the 2010 SO 2 NAAQS. Specifically, the boundaries are comprised of the entirety of Wyandotte County, Kansas.

EPA has two primary concerns with the state’s analy sis for the Nearman Station. First, the receptor grid used in the modeling analysis is inco nsistent with the Modeling TAD. Modeling receptors were only placed within Wyandotte County, Kansas, and not in the nearby Platte County, Missouri, and therefore the modeling did no t evaluate impacts from Nearman Station on receptors in Platte County. Second, four other sign ificant sources in the state of Missouri were included in the modeling for the area of analysis. Three of these sources (Veolia Energy, Sibley Station, and Hawthorn Station) were modeled with fu ture allowable emissions that are not currently federally enforceable and will not be by July 2, 2016. We are unable at this time, based on available information, to determine whether the area is meeting or not meeting the NAAQS, and EPA will consider any additional information pr ovided by KDHE addressing the above concerns in making the final designation.

At this time, our intended designations for the sta te only apply to this area and the other areas presented in this technical support document. Consi stent with the conditions in the March 2, 2015, consent decree, the EPA will evaluate and des ignate all remaining undesignated areas in Kansas by either December 31, 2017, or December 31, 2020.33 Technical Analysis for the Shawnee County, Kansas A rea

Proposed Designation Summary

After careful evaluation of the state’s recommendat ion and supporting information, as well as all available relevant information, the EPA intends to designate the area around the Tecumseh Energy Center as unclassifiable for the 2010 SO 2 NAAQS. Specifically, the boundaries are comprised of the entirety of Shawnee County, Kansas

.

The unclassifiable designation is based on the info rmation the state of Kansas provided to EPA.

Introduction

The Shawnee, Kansas area contains a stationary sour ce that according to the EPA’s Air Markets Database emitted in 2012 either more than 16,000 to ns of SO 2 or more than 2,600 tons of SO 2 and had an annual average emission rate of at least 0.45 pounds of SO 2 per one million British thermal units (lbs SO 2 /mmBTU). As of March 2, 2015, this stationary sourc e had not met the specific requirements for being “announced for reti rement.” Specifically, in 2012, the Westar Energy – Tecumseh Energy Center emitted 3,979 tons of SO 2 and had an emissions rate of 0.58
lbs SO 2 /mmBTU. Pursuant to the March 2, 2015 court-ordered schedule, the EPA must designate the area surrounding the facility by July 2, 2016.

In its submission, Kansas recommended that the area surrounding the Tecumseh Energy Center, specifically the entirety of Shawnee County, be des ignated as unclassifiable based on an assessment and characterization of air quality from the facility and other nearby sources which may have a potential impact in the area of analysis where maximum concentrations of SO 2 are expected. This assessment and characterization was based on potential future emission reductions at the Tecumseh Energy Center and an adj acent significant SO 2 source. After careful review of the state’s assessment, supporting docume ntation, and all available data, the EPA agrees with the state’s recommendation for the area and intends to designate the area as
unclassifiable.

The Tecumseh Energy Center is located in eastern Ka nsas in the northeast portion of Shawnee County. As seen in Figure 12, the facility is locat ed a few kilometers to the east of Topeka. The Tecumseh Energy Center is located just to the south of the Kansas River and lies in the relatively
flat terrain within the river basin. Also included in the figure is the adjacent Innovia Films, which is a nearby emitter of SO 2, the state’s recommended area for the unclassifiabl e designation; and, the EPA’s intended unclassifiable designation for t he area.34

Figure 12. The EPA’s intended designation for Shawn ee County, Kansas. Shown is the location of the Tecumseh Energy Center and the adja cent Innovia Films.

The discussion and analysis that follows below will reference the state’s use of the Modeling TAD, the EPA’s assessment of the state’s modeling i n accordance with the Modeling TAD, and
the factors for evaluation contained in the EPA’s M arch 20, 2015 guidance, as appropriate.

Detailed Assessment

Air Quality Data

This factor considers the SO 2 air quality monitoring data in the area surroundin g Tecumseh Energy Center. The facility is located in Shawnee C ounty; however, there are no ambient air quality monitors located in this county. The state did not include the most recent 3 years of monitoring data, i.e., 2012 – 2014, in its recommen dation for the closest county that has monitoring data, i.e., Wyandotte County, Kansas. Th e site in Wyandotte County is approximately 100 km to the east of the Tecumseh En ergy Center and located in Kansas City, Kansas. This monitoring site best represents air qu ality within and near the Kansas City metropolitan area, and would not represent the area surrounding Tecumseh Energy Center.35

However, the table below shows information related to the monitor located in Wyandotte County, which were confirmed through the EPA’s 2014 design value report for SO 2

. 8

Table 10: Available Air Quality Data for the Area C losest to Tecumseh Energy Center

Based on available ambient air quality collected be tween 2012 and 2014, the closest monitor to
Tecumseh does not show a violation of the 2010 SO 2 NAAQS. However, the absence of a violating monitor when considering the distance fro m the facility is not a sufficient technical justification to rule out that an exceedance of the 2010 SO 2 NAAQS may occur in the immediate vicinity of the facility.

Emissions and Emissions-Related Data

Evidence of SO 2 emissions from the source meeting the emissions cri teria of the March 2, 2015 consent decree, i.e., Tecumseh Energy Center, is an important factor for determining whether the immediate area is experiencing elevated levels of S O 2 concentrations. Other considerations for this factor include county level SO 2 emissions data and data for sources located within 50 km.

Kansas did not include any annual emissions data fo r point sources in Shawnee County, with the exception of the Tecumseh Energy Center consent dec ree source, nor did the state include any annual emissions data from point sources in neighbo ring Jefferson and Douglas Counties. The
EPA therefore believes that it is reasonable to eva luate data obtained from the 2011 National Emissions Inventory (NEI) 9 . The annual SO 2 emissions data for sources emitting at or above 10 0 tons per year in Shawnee and neighboring Jefferson and Douglas Counties are summarized below in Table 11. As shown in Table 11, the Innovi a Films facility is adjacent to the Tecumseh Energy Center and a significant source of SO 2

.

8 The design value report for SO 2, as well as each of the other NAAQS, can be found at this link: http://www3.epa.gov/airtrends/values.html

9 Detailed information for the 2011 NEI can be found at this link: http://www3.epa.gov/ttnchie1/net/2011inventory.html County State

Recommendation Air Quality

Systems (AQS)
Monitor ID Monitor Location Distance to
Tecumseh Energy Center (km) 2012 – 2014

SO 2 Design Value in ppb

Wyandotte Attainment 20

- 209

- 0021 Kansas City, KS 100 km 5036

Table 11: 2011 NEI SO 2 Emissions from Other Local Sources near Tecumseh En ergy Center County Facility Name Facility Subject to the
Emissions Criteria of the March 2, 2015 consent
decree? Distance to Facility
that Meets the
Consent Decree
Criteria in km Facility Total SO 2

Emissions (tons per year)

Shawnee Innovia Films No 0.5 km 1035.12 Douglas Westar Energy

– Lawrence No 20 km 2792.76

Emissions Controls

The EPA recognizes that control strategies implemen ted after the release of the 2011 NEI may not be reflected. Currently, the EPA has not receiv ed any additional information on emissions reductions resulting from controls put into place a fter the date of the emissions inventory data provided in the Table 11. However, Westar has publi cly announced that Unit 8/10 at Tecumseh will be retired by the end of calendar year 2015, w hich would represent approximately a 2/3 reduction in emissions from this facility. 10

Meteorology (Weather & Transport Patterns)

Evidence of source-receptor relationships between s pecific emissions sources and high SO 2 concentrations in the surrounding area is another i mportant factor in determining the appropriate
extent of the EPA’s intended unclassifiable area. A s shown in Figure 13, meteorological records for the nearest National Weather Service meteorolog ical station at the Topeka, Kansas Airport indicate winds blow predominantly from the south, b ut there is both a southeast and northwest component. Figure 13 was produced with data provide d as part of the state’s recommendation.

10 http://cjonline.com/news/business/2015-10-13/westar -energy-retire-three-small-generatingunits-40-affected37 Figure 13: Wind Rose for Shawnee County, Kansas

Geography and Topography (Mountain Ranges or Other Air Basin Boundaries)

As mentioned previously, the Tecumseh Energy Center is located just to the east of Topeka, along the Kansas River. The terrain is relatively f lat, as would be expected for a river basin.

Jurisdictional Boundaries

Once the geographic area associated with the immedi ate area surrounding the Tecumseh Energy Center and any nearby areas which may potentially b e contributing to elevated levels of SO 2 around the facility are determined, existing jurisd ictional boundaries are considered for the purpose of informing our intended unclassifiable ar ea. Specific attention will be given to clearly defined legal boundaries.

Kansas proposed an unclassifiable area boundary con sisting of the entirety of Shawnee County. The two largest sources of SO 2 and only sources with annual SO 2 emissions greater than 10038

tons per year within Shawnee County are the Tecumse h Energy Center and the adjacent Innovia
Films.

The EPA believes that our intended unclassifiable a rea, consisting of the entirety of Shawnee County, is comprised of clearly defined legal bound aries, and we find these boundaries to be a suitably clear basis for defining our intended uncl assifiable area.

Other Relevant Information

EPA did not receive 3 rd party information pertaining to the analysis of th e 1-hr SO 2 impacts for the Tecumseh Energy Center.

Conclusion

After careful evaluation of the state’s recommendat ion and supporting information, as well as all available relevant information, the EPA intends to designate the area around the Tecumseh Energy Center as unclassifiable for the 2010 SO 2 NAAQS. Specifically, the boundaries are comprised of the entirety of Shawnee County, Kansas

.

The unclassifiable designation is based on the info rmation the state of Kansas provided to EPA. No monitoring SO 2 data is available in the vicinity of the Tecumseh Energy Center and no modeling analysis was provided to the EPA to evalua te the Tecumseh’s impact on the surrounding area. Therefore, given this lack of mon itoring and modeling data, EPA cannot make
a technical evaluation of the 1-hr SO 2 impacts from Tecumseh Energy Center by the July 2, 2016 deadline, and we are unable, based on available inf ormation, to determine whether the area is meeting or not meeting the NAAQS. EPA will consider any additional information provided by KDHE regarding this area in making the final design ation.

At this time, our intended designations for the sta te only apply to this area and the other areas presented in this technical support document. Consi stent with the conditions in the March 2, 2015, consent decree, the EPA will evaluate and des ignate all remaining undesignated areas in Kansas by either December 31, 2017, or December 31, 2020.