# State Of Ohio 2010 Revised Sulfur Dioxide

National Ambient Air Quality Standard

Recommended Source Area Designation : W. H. Zimmer Generating Station

Prepared by: Ohio Environmental Protection Agency

Division of Air Pollution Control

August

, 2015Th is page left intentionally blankTABLE OF CONTENTS

CHAPTER ONE:

................................ ................................ ................................ ............. 1

General Discussion

................................ ................................ ................................ ......... 1 History

................................ ................................ ................................ ...................... 1 Requirements

................................ ................................ ................................ ........... 1 Ohio EPA’s Approach

................................ ................................ ................................ ..... 2

Factor 1: Dispersion Modeling

................................ ................................ .............. 3

Factor 2: Emissions Data

................................ ................................ ..................... 3

Factor 3: Meteorology

................................ ................................ .......................... 4

Factor 4: Topography and Land Use/Land Cover

................................ ................ 5

Factor 5: Jurisdictional Boundaries

................................ ................................ ...... 5

CHAPTER TW O:

................................ ................................ ................................ ............ 6 Analysis

................................ ................................ ................................ ........................... 6

Discussion:

................................ ................................ ................................ ............... 6

Factor 1: Dispersion Modeling

................................ ................................ .............. 6

Factor 2: Emissions

................................ ................................ .............................. 7

Factor 3: Meteorology

................................ ................................ .......................... 9

Factor 4: Topography and Land Use/Land Cover

................................ .............. 12

Factor 5: Jurisdictional Boundaries

................................ ................................ .... 12

APPENDICES

Appendix A: Dispersion Modeling Analysis for William H. Zimmer/Clermont Count y Appendix B: William H. Zimmer Source Area Background SO2 Analysis Appendix C: Modeling Protocol As referenced in Appendix C: Appendix D: Region 5 IDEM Q & A Response Appendix E: Region 5 States Q & A Response Appendix F: October 14, 2014 Walter C. Beck jord Shutdown Notification Appendix G: May 28, 2015 Walter C. Beckjord Shutdown Notification Appendix H: June 11, 2015 Miami Fort Shutdown NotificationThis page left intentionally blankPage | 1

State Of Ohio 2010 Revised Sulfur Dioxide National Ambient A ir Quality

Standard Recommended Designation : W. H. Zimmer Generating Station



### CHAPTER ONE :

General Discussion

History

T he United States Enviro nmental Protection Agency (U.S. EPA) promulgated

the revised National Ambient Air Quality Standard ( NAAQS ) f or sulfur dioxide ( SO 2 ) o n June 2, 20 10. U.S. EPA replaced the 24

- hour and annual standards

with a new short

- term one

- hour standard of 75 parts per billion (ppb) . The new

one

- hour SO 2 standard was published on June 22, 2010 ( 75 FR 35520) and

became effect ive on August 23, 2010

. The standard is based on the three

- year average of the annual 99th percentile of one

- hour daily maximum

concentrations

.

On August 15, 2013 , U.S. EPA published (7 8 FR 47191 ) the initial SO 2 nonattainment area designations for the on e

- hour SO 2 standard across the country (effective October 4, 2013 ). On March 2, 2015, the U.S. District Court for the Northern District of California accepted as an enforceable order an agreement between the U.S. EPA and Sierra Club and the Natural Resour ces Defense Council to resolve litigation concerning the deadline for completing designations. The court’s order directs U.S. EPA to complete designations in three steps: the first by July 2, 2016; the second by December 31, 2017 and the third by December 31, 2020. As part of the first round of designations, U.S. EPA has identified areas with newly monitored violations of the standard, or areas that contain stationary sources that emitted more than 16,000 tons of SO 2 in
2012 or emitted more than 2,600 tons of SO 2 and had an emission rate of at

least 0.45 lbs SO 2 /MMBtu in 2012. The U.S. EPA has identified two facilities in

Ohio as meeting one or more of the emissions thresholds : the General James M. Gavin Plant and the W.H. Zimmer Generating Station. Ohio E PA must

submit designation recommendations to U.S. EPA by September 18, 2015.

Requirements Pursuant to section 107(d) of the Clean Air Act (CAA), U.S. EPA must initially designate areas as either “unclassifiable”, “attainment”, or “nonattai nment” for

the 2010 one

- hour SO 2 standard. Since the original 2011 state submittals of designation recommendations and pursuant to the March 2, 2015 court order,Page | 2

new information may be relevant for future designations. CAA Section 107(d) does not require states to sub mit updated recommendations. However, U.S.

EPA will consider such information. For the round of designations to be completed by July 2, 2016, U.S. EPA requests that states submit updated recommendations and supporting information for consideration by Sep tember 18, 2015. If U.S. EPA intends to modify any state’s designation recommendation, original or updated, the state will be notified no later than 120 days prior to promulgating the final designations. For the designations due to be promulgated on or b efore July 2, 2016, this notification will occur no later than March 2, 2016. Although not required by statute, U.S. EPA will provide a 30

- day public comment period immediately following issuance of the 120

- day letters.

Section 107(d)(1) of the CAA defin es an area as “nonattainment” if it is violating the NAAQS or if it is contributing to a violation in a nearby area. The first step in making designation decisions is to identify areas for which monitoring or appropriate modeling information indicate a vi olation of the NAAQS. U.S. EPA may designate an area as attainment if it is clear that that it meets the SO 2 NAAQS and does not contribute to a violation in a nearby area.

As stated in the U.S. EPA’s Data Requirements Rule for the 1

- Hour Sulfur Dioxide (

SO 2 ) Primary National Ambient Air Quality Standard (NAAQS); Proposed Rule ( 79 FR 27445 )

, herein referred to as the proposed Data Requirements Rule, the purpose of the designations modeling is to assess actual, current air quality and that recommendations c ould include modeling the source area as attaining the standard. U.S. EPA intends to designate areas that

are modeled with actual emissions as “unclassifiable” whereas areas that are modeled with allowable emissions may be designated as “attainment.” A reas designated as unclassifiable may be subject to additional and continued analysis

to assess attainment over time

.

Ohio EPA’s Approach

This submittal is Ohio’s recommendation for the designation of the area surrounding the William H. Zimmer Generat ing Station located in Clermont County, Ohio

. This facility was identified by U.S. EPA as meeting the criteria
established in the March 2, 2015 court order. In accordance with U.S. EPA’s

final rule

, SO 2 Designation Guidance, and a March 20, 2015 memorandu m Updated Guidance for Area Designations for the 2010 Primary Sulfur Dioxide National Ambient Air Quality Standard, the starting point for the area designations would be the county boundary associated with a violation or around the SO2 source(s) in questio n, unless additional information is provided to U.S. EPA demonstrating a different boundary is appropriate. U.S. EPA’s SO 2 Designation Guidance states that U.S. EPA generally believes that in thePage | 3

absence of other relevant information it is appropriate to use county boundaries to define nonattainment areas, but they recognize that the five

- factor analysis and other information may support designating only a portion of a county as nonattainment. U.S. EPA states that modeling could be used to address several

of these factors simultane ously. Ohio used the five

- factor analysis approach and

c onducted additional modeling analysis as a part of this submittal

. While using this approach, the SO 2 Designation Guidance states this analysis should show that: 1) violation s are not occurring in nearby portions that are excluded fr om the designation area; and 2) the excluded portions do not contain emission sources

that contribute to the monitored or modeled violations , if observed

.

The following summarizes the major factor s included in Ohio’s analysis for the designation recommendation for the area surrounding the William H. Zimmer Generating Station . Specifically, Ohio has used the five factor analysis approach, including refined dispersion modeling, as recommended in the SO 2 Designation Gui dance, to support the boundary recommendation

. Ohio EPA
understands, based on the both the December 2013 Draft SO 2 NAAQS Designations Modeling Technical Assistance Document and the March 20, 2015 memorandum, that dispersion modeling ac counts simultaneously for multiple

elements of the five

- fac tor analysis. As such, Ohio believes that the m odeling analysis presented in Appendix A and summarized in this document should carry significant weight in the designation p rocess. Where appropria te, Ohio is providing additional supporting information with respect to the five

- factor designation approach.

Factor 1: Dispersion Modeling

Ohio conducted a refined dispersion modeling analysis following the guidance issued by U.S. EP A in the December 20 13 Draft SO 2 NAAQS Designations Modeling Technical Assistance Document , the March 20 memorandum, and the proposed Data Requirements Rule . The modeling analysis was based on 2012 to 2014 actual emissions from the William H. Zimmer Generating Station and

re presentative met eorological data from the same period. The methodology and

results of this anal ysis are provided in Appendix A

.

Factor 2: Emissions Data

Emissions of SO 2 for 2014 are derived from Ohio EPA’s Fee Emission Reports (FERs) which are the bas is for Oh io’s 2014 NEI submittal. Tables iden tified in this analysis show stationary sources with reported SO 2 emissions in tons per year ( TPY ) at the facility level within each county relevant to the area around the William H. Zimmer facility

. U.S. EPA ’s Designations Modeling Technical Assistance Documents suggests sources greater than the thresholds established under the proposed Data Requirements Rule located within 50Page | 4

k ilo m eters of th e William H. Zimmer facility should be considered in the analysis

o f emissions data. Further, U.S. EP A Region 5 indicated to the Region 5 states

that sources retired prior to the promulgation of a designation for a particular

area do not need to be modeled. (Appendix E ) This is consistent with the language of the propos ed Data Require ments Rule. Therefore, Ohio wi ll

consider the reduction in SO 2 emissions due to retirements as part of its recommended designation. In addition to the emissions from sources meeting the above criteria, the impact of the William H. Zimmer f acility are directly modeled as a part of Ohio’s designation recommendation analysis. Emissions data for the William H. Zimmer facility were provided to Ohio EPA by the owner/operator of the facility, Dynegy Zimmer, LLC.

Factor 3: Meteorology

The meteo rology review looks at wind data gathered at stations in and near Ohio by the National Weather Service (NWS). Information presente d under this

factor is indicative of annual average winds . These data may also suggest that emissions originating from some directi ons may be more prone to contribute

than emissions in other directions.

Ohio is located in what is meteorologically termed the Mid

- Latitudes. For pollutant dispersion, the most important meteorological parameter is wind speed

and wind direction. In this region, surface weather systems predominantly travel from west to east, guided by either the sub

- tropical or polar jet streams. The resulting surface transport winds associated with these systems will generally have a western component with add itional southern components in the summer and northern components in the winter, although, on any given day, winds can blow from any direction. Discussions regarding this factor will show representative w ind roses for the source area and SO 2 sources surrou nding the

William H

. Zimmer facility.

The major geographic feature affecting winds in the area surrounding the William H. Zimmer facility is the hilly terrai n and the Ohio River valley . This area

has significant forested areas which modify the surface roughness lengths and can impact wind speed and wind direction. The Covin gton airport w ind roses best illustrate the range of wind directions and wind speeds associated with this

area

.

A significant portion of this factor is accounted for by the dispers ion modeling analysis conducted for this area. The AERSURFACE preprocessor component of the AERMOD model accounts for land use and its impact on surface roughness lengths, albedo, and Bowen ratio. The meteorological inputs to

AERMOD itself are taken from measurements at the Covington airport.Page | 5

Factor 4: Topography and Land Use/Land Cover

The topography and land use/land cover analysis looks at physical features and

land use or land cover that might have an effect on the airshed and, therefore,

the dist ribution of pollutants over an area. The William H. Zimmer facilit y is

located in the Ohio River v alley, and therefore some portions of the area may experience inversions. However, the geographical and topographical features of the area are not likely to limit or impact the transport of SO2 in a significant manner. Furthermore, the topography of the region is accounted for in the dispersion modeling analysis via the AERMAP preprocessor, and the impact of land use is accounted for via the AERSURFACE prepr ocessor. As such, Ohio EPA does not consider topography and land use to be a significant factor for this analysis beyond what is analyzed directly via the refined dispersion modeling analysis

.

Factor 5: Jurisdictional Boundaries

The analysis of jurisd ictional boundaries looks at the planning and organizational structure of an area to determine if the implementation of controls in a potential

nonattainment area can be carried out in a cohesive manner. Core Based Statistical Areas (CBSAs), comprised of Metropolitan Statistical Areas (MSAs) and Combined Statistical Areas (CSAs), boundaries were considered for these

recommendations.Page | 6



### CHAPTER TWO:

Analysis

Discussion:

Based on the five factor analysis below, Ohi o EPA is recommend ing the portion of Clermont County, excluding Pierce Township, be designated as attainment for

the 2010 one

- hour SO 2 standard

. This recommendation encompasses the following townships in Clermont County: Batavia, Franklin, Goshen, Jackson, Miami, Monroe, Oh io, Stonelick, Tate, Union, Washington, Wayne, and Williamsburg. The following discussion and info rmation is relevant to those townships in Clermont County listed above , excluding Pierce Township

.

As detailed under Factor 1, Ohio EPA modeled actual SO 2 e missions from the William H. Zimmer Generating Station, years 2012

- 2014. No exceedances of the standard were modeled inclusive of a conservative 11 ppb background

concentration. Derivation of the background concentration is detailed in Appendix B of this submittal.

Factor 1: Dispersion Modeling

Ohio EPA modeled actual emissions from the William H. Zimmer Generating Station for years 2012

- 2014, inclusive of an 11 ppb background. The full details of the modeling analy sis are presented in Appendix A of t his submittal. Appendix C includes the modeling protocol. For this analysis, the maximum

modeled 3

- year design value, years 2012

- 2014, was 118.2265  g/m 3 (147.0025

 g/m 3 , with background). An area meets the standard of 75 ppb if a
concentration of 196.2  g/m 3 or lower is modeled. Thus, no exceedance of the

standard was modeled. The results of thi s analysis are shown in Figure 1 . Note

that for clari ty, only design values of 100  g/m 3 or greater are displayed.Page | 7 Figure 1 : Maximum SO2 impacts, William H. Zimmer facility, 2012

- 2014.

Concentrati ons are shown in  g/m 3

.

The maximum 3

- year design value was modeled approximately 3 50 meters from the facility fenceline and approximatel y 1,200 meters from the largest SO 2 source. The spatial distribution of modeled concentrations greater than or equal

to 100  g/m 3 were located in a 4 to 5 km radius of the primary emissions so urce

at t he William H. Zimmer facility, as detailed in Appendix A

. It should be noted that Ohio’s modeling analysis was conducted over a 50 x 50 kilometer modeling domain with additional receptors placed to encompass the entirety of Clermont County.

Factor 2: Em issions

In 2014, there were 83,038 TPY of actual SO 2 emissions from Ohio and Kentucky sources within 5 0 k ilo m eters of the border of Clermont County from facilities that might potentially need to be modeled under the requirements of the proposed Data Requi rements Rule

. 46,101 TPY of actual 2014 SO 2 emissions are within Clermont County itself

. These sources are shown in Table 1

.Page | 8 State County Facility ID Facility Name 2014 SO2
Emissions (TPY) Distance from W. H.
Zimmer (km)

OH Clermont 1413090154 W. H. Zim mer Power Station 13,498

--

OH Clermont 1413100008 Duke Energy Ohio, W.C. Beckjord

Station 32,603 14.7

Clermont Total 46,101

OH Hamilton 1431350093 Miami Fort Power Station 28,479 57.1

OH Hamilton 1431394148 DTE St. Bernard, LLC 1,666 41.6

Hamilt on Total 30,145

KY Boone Duke Energy Kentucky, East Bend

Station 2,103 54.53

Boone Total 2,103

KY Mason Sp urlock Station 4,689 40.9

Mason Total 4,689

Grand Total 83,038

Table 1 : 2014 annual SO 2 emissions, William H. Zimm er and nearby sources



## .Page | 9

A significant aspect of Ohio’s recommended designation is the cessation of operations at the Walter C. Beckjord Station as of June 1, 2015. (Appendix F, Appendix G) This represents an emission reduction of approximately 34% fro m the area surrounding the William H. Zimmer facility, and an approximately 71% reduction in Clermont County. Additionally, Unit 6 at the Miami Fort Power Station ceased operation as of June 1 , 2015. (Appendix H) This unit emitted 18,865 tons of SO2 in 2 014. These shutdowns account for a reduction of 51,468 tons from 2014, or 62% from the area surrounding the William H. Zimmer facility. The distance between the remaining facilities and the area impacted by emissions from the William H. Zimmer facility, as well as the meteorology of the

area (Factor 3) , would indicate that emissions from these remaining facilities are unlikely to impact ambient SO 2 concentrations in Clermont County beyond what is accounted for in the background concentration

.

Factor 3: Meteorology

Please refer to the Factor 3 general discussion at the beginning of this document for general meteorological information applicable to Cler mont County and the William H. Zimmer facility

. Per U.S. EPA guidance, dispersion modeling

accounts fo r the majority of to pographical and land use features that influence the meteorology of Clermont County. Of particular importance in Ohio’s designation recommendation for this area is the annual trend s and distribution of
wind directions in this area, whi ch are best represented by data from the National Weather Service station located at the Cincinnati Northern Kentucky Airport (Covington) . Wind roses from this station, years 2012 to 2014, are shown in Figure 2 , below.Page | 10 Figure 2 : Covington wind roses, 2012

- 2014Page | 11

The predominant wind directions were used, in p art, to inform which facilities in

Table 1 , in addition to William H. Zimmer, may potentially impact ambient SO 2 concentrations in Clermont County not account ed for by bac kground and therefore necessitate inclusion in the dispersion modeling analysis

. As shown in Figure 2, the predominant winds in the source area originate from the south and

south

- west and to a lesser degree from the west. Figure 3 shows the locati on of

a ll facilities in Table 1

, as well as a composite wind rose, years 2012

- 2014 , from the Covington meteorological station

.

Figure 3 : SO 2 sources within 50 km of Clermont County, Ohio.

Considering the predominant wind directions , Ohio does not conclude that emissions from Spu rlock Station , located to the south

- east of the source area

, impact ambient SO 2 concentrations in Clermont County. T he largest SO 2 source based on 2014 data , Walter C. Beckjord, is no longer operational as of June 1,

2015 . Wind direction data suggests that emissions from Miami Fort Station and

East Bend , located to the west of Clermont County, could po tentially impact

ambient SO 2 concentrations ; these sources are more than 40 k ilo m eters distant

from the neare st part of Clermont County and as such, Ohio does not conclude

that emissions from these sources impact ambient SO 2 concentrations beyond

the back ground level accounted for in the refined dispersion modeling analysis

. Lastly, wind direction data suggests that emissions from DTE St . Bernard may impact ambient SO 2 concentrations in Clermont County under some meteorological conditions . Please refer to Factor 2, which shows that this facility has relatively low annual emissions. Further, the largest emission unit at DTE St. Bernard has a stack height of 65 m eters

. It is therefore likely that thePage | 12

maximum impacts of this facility would occur within approximately 650 m eters of the facility. Screen modeling analyses indica te that the maximum impact

decrease s by approximately 95% over the 17 k ilometers distance to the border of Clermont County. Ohio does not conclude that impacts from DTE St. Berna rd impact ambient SO 2 concentrations in Clermont County beyond what is accounted for in background. Ohio concludes t hat, following the closure of the Walter C. Beckjord facility, the primary source of SO 2 in Clermont County is the William H. Zimmer facility, and that the impact of those facilities in Table 1 not explicitly modeled are represented adequately and conserva tively by the background concentration included in the Factor 1 analysis.

Factor 4: Topography and Land Use/Land Cover

Please refer to the general discussion of Factor 4 at the beginning of this document. Ohio, consistent with U.S. EPA guidance, unde rstands that the topography and land use characteristics influencing meteorology and the dispersion of SO 2 emissions from the Will iam H. Zimmer facility are adequately accounted for via the dispersion modeling analysis. Please refer to the Factor 1

sectio n of this Chapter.

Factor 5: Jurisdictional Boundaries

The Cincinnati , OH

- KY

- IN MSA includes Clermont , Brown, Butler, Hamilton, and

Warren Counties in Ohio , as well as Boone, Bracken, Campbell, Gallatin, Kenton, Mason, Pendleton Counties in Kentucky and Dearborn, Ohio, and Union

Counties in Indiana

. The Ohio EPA Central Office and the Southwest Ohio Air Quality Agency are responsible for air quality p lanning within all areas of Clermont County. Clermont County, with the exception of Pierce Township, is

n ot currently nonat tainment for the 2010 one

- hour SO 2 standard. The dispersion modeling analysis conducted by Ohio was inclusive of the entirety of Clermont County. Ohio, in a separate submission, is requesting that P ierce Township be redesignated m ainten ance for the 2010 one

- hour SO 2 standard . In this submission, Ohio is recommending, based on a five

- factor analysis, that t he remainder of Clermont County: Batavia, Franklin, Goshen, Jackson, Miami, Monroe, Ohio, Stonelick, Tate, Union, Washington, Wayne, and Williamsburg Townships, be designated u nclassifiable /attainment for the 2010 one

- hour SO 2 standard. Townships in Ohio have well

- established boundaries , and Ohio believes they are a suitable administrative basis for this recommendation.Page | 13 T his page left intentionally blan k