# RE VISED DESIGNATION

RE COMMENDATION

FOR SULFUR DIOXIDE

Buffalo-C heektowaga , NY C SA
2010 Primary National Ambient Air Quality Standard

September 2015

DIVISION OF AIR RESO URCES

Bureau of Air Quality Planning

Albany, NY 12233

- 3251 P: (518) 402

- 8396 | F: (518) 402

- 9035 | dar.sips @dec.ny.gov

www.dec.ny.gov

### Table of Contents
Introduction

..................................................................................................................... 3 Background

..................................................................................................................... 4 NAAQS and Designations

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

EPA’s Data Requirement Rule

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

SO 2 Emissions Monitoring and Monitoring Data

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

New York’s SO 2 Emissions Monitoring System

................................................................ 7 Figure 1: 2015 Ambient Air Monitoring Network SO 2 Monitoring Sites

............................. 7
Monitoring Data

............................................................................................................... 8

Table 1: SO 2 Design Values for Monitors of Concern from 2011 through 2014*

............... 8

Table 2: SO 2 Design Values for Tonawanda Monitors

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

TONAWANDA MONITOR STREET ADDRESS

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

Table 3: Peak 1

- hour SO 2 Concentrations for Tonawanda Monitors

............................... 10 Supporting Information (Five

- Factor Analysis)

.............................................................. 11 Factor 1: Dispersion Modeling

........................................................................................ 11

Factor 2: Emissions

- Related Data

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

Table 4: SO 2 Emissions Trends for Cattaraugus, Erie and Niagara Counties

.................. 14

Table 5: SO 2 Emissions (tons): Cattaraugus County Point Sources

................................ 15

Table 6: SO 2 Emissions (tons): Erie County Point Sources

............................................. 15 Figure 2: Sources Emitting Greater Than 40 tons/year of SO 2 near Huntley

................... 16

Table 7: SO 2 Emissions (tons): Niagara County Point Sources

....................................... 17 Figure 3: Sources Emitting Greater Than 40 tons/year of SO 2 near Somerset

................ 17 Table 8: Cattaraugus County Airports: 2011 Emissions Inventory

................................... 18 Table 9: Erie County Airports: 2011 Emissions Inventory

................................................ 19 Table 10: Niagara County Airports: 2011 Emissions Inventory

........................................ 20
Factor 3: Meteorology

..................................................................................................... 21
Figure 4: Wind Roses from Buffalo Niagara International Airport and Niagara Falls International Airport

......................................................................................................... 21 Figure 5: SO 2 Pollution Wind Rose for Tonawanda II Monitor

......................................... 22 Factor 4: Geography and Topography

............................................................................ 24

Factor 5: Jurisdictional Boundaries

................................................................................. 25

Recommendations

.......................................................................................................... 26

1A PPENDIX A: Air Quality Modeling for Huntley Generating Station

.............................. 27 APPENDIX B: Air Quality Modeling for Somerset Station

............................................. 28

2

### Introduction

S ulfur dioxide (SO 2 ) is one of a group of highly reactive gasses known as “oxides of sulfur.” The largest sources of SO 2 emissions are from fossil fuel combustion at power plants and other industrial facilities

. Smaller sources of SO 2 emissions include industrial processes and the burning of high sulfur containing fuels by locomotives, large ships, and non

- road equipment. SO 2 is linked with a number of adverse effects on the respiratory system. Exposure to sulfur dioxide can cause ir ritation and/or inflammation of the skin and mucous membranes of the eyes, nose, throat, and lungs. The respiratory system is particularly affected during heavy physical activity. High concentrations of SO 2 can affect lung function, worsen asthma attacks, and aggravate existing heart disease in sensitive groups, such as children, the elderly, and those with chronic lung disease.

O n March 2, 2015, the U.S. District Court for the Northern District of California accepted as an enforceable order an agreement between the EPA and Sierra Club and Natural Resources Defense Council to resolve litigation concerning the deadline for completing designations for the 2010 p rimary SO 2 National Ambient Air Quality Standard (NAAQS). In the first round of designations to be completed by EPA no later than July 2, 2016, EPA must designate two groups of areas: 1) areas that have newly monitored violations of the 2010 SO 2 NAAQS , and 2) areas that contain any stationary source that

, according to the EPA’s Air Markets Database

, eit her 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 and that has not been announced (as of March 2, 2015) for retirement.

E PA has identified two electric power plant sources in New York State (NRG Huntley Generating Station (Huntley) , Erie County and AES Somerset LLC (Somerset) , Niagara County) as meeting the first

- round criteria established in the court order. Consequently, t he New York State Department of Environmental Conservation (DEC) is submitting a revised designation request for the entire Buffalo

- Cheektowaga, NY Combined Statistical Area (CSA) for the 2010 primary SO 2 NAAQS pursuant to section 107(d) of the Clean Air Act (CAA). Since the Buffalo

- Cheektowaga, NY CSA also includes Cattaraugus County, DEC included an analysis of the attainment status for Ca ttaraugus County.

3

### Backgrou n d

NAAQS and Designations

On June 2, 2010, EPA strengthened the primary SO 2 NAAQS by establishing a new 1

- hour standard at a level of 75 parts per billion (ppb) . At the same time, EPA revoked the two existing primary standards of 140 ppb evaluated over 24

- hours, and 30 ppb evaluated over an entire year

, because they will not add additional public health prot ection given a 1

- hour standard of 75 ppb. The 2010 SO 2 standard includes a new form ; the 3

- year average of the 99 th percentile of the annual distribution of daily maximum 1

- hour concentrations.

DEC submitted New York’s designation request for the 2010 SO 2 NAAQS on June 1, 2011

. This request provided details of New York’s SO 2 Emissions Monitoring System in 2011 as well as actual monitoring data for New York and adjacent states. DEC recommended that all areas of New York be designated as “attainment”, with the exception of the Poughkeepsie

- Middletown

- Newburgh Core

- Based Statistical Area (CBSA). DEC recommended that this area be classified as “unclassifiable” since sufficient monit oring data was not available at the time to make an attainment determination. No area of the State indicated nonattainment based on the monitoring data.

On July 27, 2012

, EPA e xtend ed the deadline for area designations for the 2010 primary SO 2 standard b y approximately 1 year due to comments received on the approach for informing initial designations, and remaining uncertainties about the analytic approach states would use for designation determinations and for general implementation. With this extension , EPA intended to complete initial designations by June 3, 2013.

EPA responded to New York’s June 1, 2011 designation request on February 6, 2013. At that time, EPA was only proceeding with designating as nonattainment areas in locations where existing monitoring data for 2009

- 2011 indicated violations of the 1

- hour SO 2 standard. Since EPA’s review of the monitoring data for 2009

- 2011 showed no violations of the 2010 SO 2 NAAQS in any areas in New York State, EPA deferred action to designate any areas in New York.

4T hr ee lawsuits were filed against EPA alleging the agency failed to desi gnate areas by June 2013 . O n March 2, 2015 U.S. District Court for the Northern District of California issued an enforceable order under which EPA must complete 1- hour SO 2 NAAQS designations of the remaining areas of the country in up to three ad ditional rounds: the first round by July 2, 2016, the second round by December 31, 2017, and the final round by December 31, 2020.

1. I n the designations to be completed by July 2, 2016, EPA will designate in two group s: 1. A reas that have monitored violations of the 2010 SO 2 standard based on 2013

– 2015 air quality data

. 2. A reas that contain any stationary source not announced for retirement that according to EPA’s Air Markets Database emitted in 2012 either (a) more than 16,000 tons of SO 2 , or (b) more than 2,600 tons of SO 2 and had an average emission rate of at least 0.45 lbs

. SO 2 / mmBtu

.

O n March 20, 2015, EPA notified DEC that two facilities in New York were identified as mee ting the nonattainment designation criteria for emitting more than 2,600 tons of SO 2 and having an emission rate of at least 0.45 lbs. SO 2 / mmBtu in 2012 and have not announced (as of March 2, 2015) that they will be retired. This revised designation recommendation addresses this issue.

2. T he court’s order directs the EPA to complete an additional round of area designations by December 31, 2017 addressing areas where states have not installed and begun operating a new SO 2 monitoring network meeting the EPA’s specifications referenced in the Agency’s anticipated final titled, “Data Requirements Rule for the 1

- hour SO 2 primary NAAQS”.

3. Las tly, the court’s order directs the EPA to designate all remaining areas by December 31, 2020.

5

### EPA’s Data Requirement Rule

O n April 17, 2014, E PA proposed requirements for air agencies to characterize SO 2 air quality more extensively for purposes of implementing the 2010 SO 2 NAAQS. Air agencies would have the flexibility to characterize air quality using either modeling of actual source emissions or using appropriately sited ambient air quality monitors. EPA intends to use these data in two future rounds of area designations in 2017 and 2020.

T he proposed Data Requirements Rule inclu des options for emissions thresholds which would identify the sources around which air agencies would need to characterize SO 2 air quality. To increase public health protection in more highly populated areas, each option includes a lower annual emissions threshold for sources located in metropolitan areas greater than 1 million in population, and a higher threshold for sources outside these areas.

1. O ption 1 would cover sources greater than 1

, 000 tons of SO 2 in metro areas with population greater than 1 million; and sources greater than 2

, 000 tons everywhere else.

2. O ption 2 would cover sources greater than 2

, 000 tons of SO 2 in metro areas with population greater than 1 million; and sources greater than 5

, 000 tons everywhere else.

3. O ption 3 would cover sources greater than 3

, 000 tons of SO 2 in metro areas with population greater than 1 million; and sources greater than 10,000 tons everywhere else.

T he final proposed D ata R equirements R ule was submitted to the Office of Management and Budget on May 28, 2015 with a final rule expected in October 2015. The outcome of the final rule will impact how New York and the EPA proceed with the second round of designation recommendations.

6

### SO 2 

### Emissions Monitoring and Monitoring Data

New York’s SO 2 

### Emissions Monitoring System

T he DEC Division of Air Resources operates an ambient air monitoring network for various air contaminants within New York State , including SO 2 . As required by federal regulations, DEC prepares an annual monitoring network plan, which describes in detail the specifics of the monitoring network. This plan includes an annual review of the existing monitoring network to determine the adequacy of the network and to propose any network modifications. Pursuant to the proposed 2015 Annual Monitoring Network Plan, which can be found at http://www.dec.ny.gov/chemical/33276.html

, New York State’s existing SO 2 monitoring locations are shown in Figure 1.

Fi g ure 1: 2015 Ambient Air Monitoring Network SO 2 Monitoring Sites

7

### Monitoring Data

T he 2010 primary SO 2 NAAQS is set at a level of 75 ppb and takes the form of 99th percentile of 1

- hour daily maximum concentrations, averaged over 3 years

. For example, the design value for 201 4 is calculated using monitoring data from 20 12 , 201 3 and 201 4. Table 1 provides design values for the SO 2 monitors in and closest to Erie and Niagara counties. When considering all design values from 2011 through 2014, all monitors attain the 2010 primary SO 2 NAAQS by a large margin with SO 2 emissions

c ontinu ing to decline.

Ta ble 1: SO 2 Design Values for Monitors of Concern from 2011 through 2014 *

Monitor County Location SO 2 Design Values ( ppb ) 2011 2012 2013 2014

Rochester Monroe RG&E Substation @ 2 Yarmouth Road 24 23 20 20

Buffalo Erie Trailer @ 185 Dingens Street 19 17 15 10

Brookside

Terrace (Tonawanda II) Erie 192 Brookside Terrace West 32 29 25 22

Dunkirk Chautauqua STP @ Wright Park Drive 34 27 22 18

Addison Steuben Pinnacle State Park 16 12 10 9

Niagara

Falls* Niagara Frontier Ave. @ 55 th Street 17 14 N/A N/A

Source : EPA AQS Design Value Report generated August 3, 2015. *The Niagara Falls monitor ceased operation at the end of 2012. While not shown in Figure 1, the dat a f rom this monitor is used in the dispersion modeling analysis.

T he Erie County monitor now located to 192 Brookside Terrace West (Tonawanda II) was originally located at 779 Two Mile Creek Road ( Tonawanda I). It was moved as part of the Tonawanda Community Air Quality Study in 2007 and now borders a residential neighborhood and industrial complex approximately 0.2 mile northeast of the original s ite. While this move occurred well before the new 1

- hour SO 2 NAAQS became effective, DEC wants to assure EPA that moving the monitor was not the cause of the sharp decline in peak 1

- hour SO 2 concentrations and design values that occurred during the same time period

.

T he primary reason for the sharp decline in peak 1- hour SO 2 concentrations and design values was the precipitous drop in SO 2 emissions from stationary sources located in Erie County as a result of the PSD (Prevention of Significant Deterioration) Consent

8D ecree s involving coal power generating facilities and new regulations taking effect at the time , especially 6 NYCRR Part 245, CAIR SO 2 Trading Program. Erie County stationary source emissions decreased from 11,609 tons of SO 2 in 2007 to 7,422 tons of SO 2 in 2008. Huntley alone decreased from 10,613 tons of SO 2 in 2007 to 6,853 tons of SO 2 in 2008. Additionally, EPA implemented Ultra Low Sulfur Diesel (ULSD) standards for on

- road diesel fuel. The new requirement of 15 ppm was phased in from 2006

- 2010.

M onitoring data show s that the Tonawanda I monitor e xceeded the 1

- hour SO 2 NAAQS of 75 ppb in 2007 with a design value of 119 ppb and in 2008 with a design value of 88 ppb. Since this is the only monitor that exceed ed the 1- hour SO 2 NAAQS with actual monitor data, these values were examined more closely. Because of the Tonawanda I monitor’s proximity to the new Tonawanda II monitor location

, d esign v alues were calculated for the years that were missing data at that location by substituting the values for the adjacent monitor instead; that allowed DEC to calculate values for all three

- year Design Value periods, for both monitors. Those three

- year d esign v alue periods are shown below in red in order to distinguish them from the non

- substituted values:

Ta ble 2: SO 2 Design Values for Tonawanda Monitors

TONAWANDA MONITOR STREET ADDRESS SO 2 Design Values (ppb)

2007 2008 2009 2010

192 BROOKSIDE TERRACE WEST (Tonawanda II ) 88 62 39 36

779 TWO MILE CREEK ROAD (Tonawanda I ) 119 88 65 30

9T able 3 provides additional e vidence that the monitor site change in Tonawanda was not the reason for the sharp decline observed in peak 1

- hour concentrations. Both monitor s were operating for the sixth month period from July 2007 through December 2007 and showed comparable peak concentrations and a precipitous drop in November 2007. Sampling at the Tonawanda I monitor terminated on December 31, 2007.

T able 3: Peak 1

- hour SO 2 Concentrations for Tonawanda Monitors

Month Tonawanda I (ppb) Tonawanda II (ppb) July 2007 17 40 August 2007 51 39 September 2007 32 35 October 2007 63 58 November 2007 24 18 December 2007 31 25

With a decreasing trend in SO 2 values clearly demonstrated for these two monitoring locations since 200 7 , it can be concluded that the Tonawanda II monitoring location does not present an area of heightened concern for the 2010 SO 2 NAAQS.

10

### Supporting Information (Five

- Factor Analysis)

Factor 1: Dispersion Modeling

D EC performed dispersion modeling to assess the area s around Huntley and Somerset in the context of the proposed federal 1- hour SO 2 Data Requirements Rule (DRR). DEC’s methodology was based on policies and procedures contained in EPA’s Guideline on Air Quality Models (40 CFR Appendix W) and DEC’s Air Quality Modeling Procedures as outlined in DAR

- 10 / NYSDEC Guidelines on Dispersion Modeling Procedures for Air Quality Impact Analysis, modified by the SO 2 NAAQS Designations Modeling Technical Assistance Document (Modeling TAD) where applicable.

Fo r t he Huntley modeling analysis (2012

- 2014 time period)

, included in this report as Appendix A, a ctual hourly emissions data obtained from the facility were matched with three years of concurrent surface and upper

- air meteorological data from Buffalo Niaga ra International Airport to run AERMOD version 14134 using t rue stack height regardless of Good Engineering Practice ( GEP ) . AERMOD calculated impacts show that Huntley contribute d 44.1 ppb to the 54.3 ppb 4 th highest concentration th at include s seasonally

- based hourly background concentrations for SO 2

. This maximum impact, which is located at the southeastern boundary of the facility’s property, falls well below the 2010 SO 2 NAAQS of 75 ppb.

F or the Somerset modeling analysis (2011

- 2013 time period)

, included in this report as Appendix B, AERMOD version 14134 was run for two scenarios: 1. Three years of hourly emissions data obtained from the facility were matched with 3 years of concurrent meteorological data from both Buffalo Niagara International Airport and Niagara Falls International Airport to run AERMOD version 14134 using the actual stack height. 2. A fixed emission rate based on a permit limit to comply with the Mercury Air Toxics Standards (MATS) was modeled with 5 years of meteorological data and the GEP stack height.

A E RMOD calculated impacts for Scenario 1 show that Somerset contributes 35. 1 ppb to the 42.6 ppb 4th highest concentration that include s seasonally

- based hourly background concentrations for SO 2

. AERMOD ca lculated impacts for Scenario 2 show that Somerset contributes 13. 1 ppb to the 20.6 ppb 4th highest concentration that includes seasonally

- based hourly background concentrations for SO 2

. Th e maximum impact from both scenarios, which occurs just northeast and southeast of the facility’s property, falls well below the 2010 SO 2 NAAQS of 75 ppb . Given the recent Su preme Court decision 1 resulting in an uncertain future for the MATS rule, only Scenario 1 was considered in making this designation recommendation

.

1 June 29, 2015: MICHIGAN ET AL. v. ENVIRONMENTAL PROTECTION AGENCY ET AL.

http://www.supremecourt.gov/opinions/14pdf/14

- 46_10n2.pdf 11

### Factor 2: Emissions-R elated D ata

O ver the years, New York has adopted several regulations that have had a significant impact on reducing SO 2 emissions. The se include:

Regulation Title 6 NYCRR Part 248 Use of Ultra Low Sulfur Diesel Fuel and Best Available Retrofit Technology for Heavy Duty Vehicles 6 NYCRR Subpart 225

- 1 Fuel Use and Composition

– Sulfur Limitations 6 NYCRR Part 245 CAIR SO 2 Trading Program 6 NYCRR Part 249 Best Available Retrofit Technology (BART)

6 N YCRR Part 248 (regulation effective 2009) requires the use of Ultra low sulfur diesel fuel (ULSD) having a content of 0.0015 percent (15 ppm) of sulfur or less and applies to all heavy duty vehicles except for:

(1 ) locomotives; (2) alternative fuel vehicles; (3) any HDV subject to a lease or contract entered into or last renewed prior to February 12, 2007; and (4) any on road vehicle with engine model years prior to 1960.

6 N YCRR Part 248 also requ i res that o n or after December 31, 2013, all diesel powered heavy duty vehicles owned by, operated by, or leased by each BART regulated entity or which are owned by, operated by, or leased by a contractor and used to provide labor, services, materials and/or equipment on behalf of a BART regulated entity to perform regulated entity work were required to utilize and maintain BART.

F or 6 NYCRR Part 225:

• 6 NYCRR Part 225

- 1.2(c) requires owners and/or operators of any stationary combustion installation in Erie and Niagara Counties that fires solid fuels are limited to the firing of solid fuel with a maximu m sulfur content of 1.7 pounds per million Btu and an average sulfur content of 1.4 pounds per million Btu on or after July 1, 2014

.

• 6 NYCRR Part 225

- 1.2(e) requires o wners and/or operators of any stationary combustion installation in Erie and Niagara C ounties that fires residual oil are limited to the purchase of residual oil with a sulfur content of 0.50 percent sulfur by weight low on or after July 1, 2014, and are limited to the firing of residual oil with a sulfur content of 0.50 percent sulfur by weight on or after July 1, 2016

.

12• 6 NYCRR Part 225

- 1.2 (f) requires owners and/or operators of commercial, industrial, or residential emission sources that fire number two heating oil on or after July 1, 2012 are limited to the purchase of number two heating oil with 0.0015 percent sulfur by weight or less.

• 6 NYCRR Part 225

- 1.2( g) requires o wners and/or operators of a stationary combustion installation that fires distillate oil other than number two heating oil are limited to the purchase of distillate oil with 0.0015 percent sulfur by weight or less on or after July 1, 2014.

• 6 NYCRR Part 225

- 1( h) requires owners and/or operators of any stationary combustion installation that fires distillate oil including number two heating oil are limited to the firing of distillate oil with 0.0015 percent sulfur by weight or less on or after July 1, 2016.

• 6 NYCRR Part 225

- 1.2( i) requires owners and/or operators of any stationary

c ombustion installation that fires waste oil on or after July 1, 2014 are limited to the firing of waste oil with 0.75 percent sulfur by weight or less.

6 N YCRR Part 245 established an annual SO 2 Budget Trading Program for EGU’s beginning in 2010 (New York State emissions cap = 135,139 tons) and require d further emission reductions starting January 1, 2015

. However, 6 NYCRR Part 245 has been

s uperseded by the federal Cross

- State Air Pollution Rule (CSAPR) with a 2015 (Phase I) New York State SO 2 emissions cap of 36,296 tons. CSAPR Phase II in 2017 has a New York State S O 2 emissions cap of 27,556 tons. In Erie County, Huntley has a 2015 SO 2 allocation of 2,673 tons which is reduced to 1,950 tons in 2017. In Niagara County, Somerset has a 2015 allocation of 5,147 tons which is reduced to 3,754 tons in 2017. These are substantial SO 2 emissions reductions that are expected to have the continued effect of lower 1

- hour SO 2 design values in Erie and Niagara Counties, as well as statewide.

6 NYCRR Part 249 restricts the emissions of visibility

- impairing pollutants, including SO 2 , by requiring the installation of Best Available Retrofit Technology (BART) on a BART

- eligible stationary source to reduce regional haze and restore natural visibility conditions to Federal Class I Areas

. While no BART

- eligible stationary sources exist in Erie and Niagara counties, reductions in SO 2 emissions from BART

- eligible stationary

sources will be realized in other parts of New York State

.

13T able 4 provides SO 2 emissions trends for Cattaraugus, Erie and Niagara counties. All three counties exhibit a declining emissions trend from 2005 t o 2014, with the exception of Niagara County. The 2011 point source emissions for Niagara County w as noticeably higher than previous years because Somerset emitted approximately 10,024 tons of SO 2 that year. Since 2011 , Somerset’s emissions have returned to pre

- 2011 levels with 2014 emissions being less than half the 2011 emissions . (See Table 7).

Table 4: SO 2 Emissions Trends for Cattaraugus, Erie and Niagara Counties County Source Category 2005 (tons) 2008 (tons) 2011 (tons) 2014 * (tons) Cattaraugus Point 2.37 0.74 0.36 0.81 Non Point 955.50 405.37 275.64 186.87 On Road 49.51 9.01 10.02 10.02 Non Road 49.73 39.88 1.14 1.14

Total 1,057

. 11 455

. 00 287

. 16 198.84

Erie Point 19,897.63 7,422.75 4,924.42 3,456.11 Non Point 8,918.02 3,849.50 2,824.83 1,808.82 On Road 418.85 102.31 68.26 68.26 Non Road 508.49 78.13 8.49 8.49

Total 29,742.98 11,452.69 7,826.00 4, 341.68

Niagara Point 4,255.33 5,058.62 10,759.85 5,855.06 Non Point 2,043.80 1,101.07 853.99 652.20 On Road 73.38 18.83 13.97 13.97 Non Road 379.13 21.26 2.42 2.42

Total 6,751.64 6,199.78 11,630.22 6, 523 .6 5

*2014 Point Source Emissions Data is preliminary data. 2014 Non

- Point Emissions Data is projected. 2014 On

- Road and Non

Road E missions I nventories are under development, and, because they constitute a small fraction of the total inventory, were assumed constant from 2011 for purposes of this analysis

.

14T able s 5, 6 and 7 provide SO 2 emissions for point sources in Cattaraugus, Erie and Niagara Counties respectively. Generally speaking, there is a downward trend in SO 2 emissions from point sources in all three counties.

Table 5 : SO 2 Emissions (tons): Cattaraugus County Point Sources Facility 2007 2008 2009 2010 2011 2012 2013 2014

Indeck Olean Energy Center 1.42 0.74 0. 46 0 .7 1 0

. 36 0

. 33 0

. 35 0 .8 1 Laidlaw Energy * 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

Total 1.42 0.74 0. 46 0 .7 1 0.36 0.33 0.35 0 .8 1 *Laidlaw Energy has not operated during the period of 2007

- 2014, but still has a valid Title V permit.

Table 6 : SO 2 Emissions (tons): Erie County Point Sources Facility 2007 2008 2009 2010 2011 2012 2013 2014

Huntley G enerating Station 10,612.50 6,852.60 6,043.92 6,041.41 4,315.60 2,715.50 3,218.00 3,192.00 PVS Chemical Solutions Inc * 198.38 121.73 96.32 147.88 138.14 109.06 139.29 163.11 3M Tonawanda * 52.96 64.78 41.50 48.90 37.08 43.32 45.33 47.68 Chaffee Landfill 17.99 44.43 47.31 42.54 48.66 49.78 46.39 45.61 Bird Island STP * 4.02 3.67 3.95 3.70 3.69 3.50 3.75 3.84 Tennessee Gas Pipeline Co Comp Stat 229 0.07 0.09 0.14 0.16 0.18 0.14 0.57 2.68 Indeck

- Yerkes Energy Services 0.22 0.30 0.27 0.21 0.26 0.29 0.41 0.41 Tonawanda Engine Plant

- GM Powertrain 0.26 0.23 0.09 0.20 0.15 0.19 0.17 0.28 Aurubis Buffalo Inc ( a ka. Luvata Buffalo Inc) * 0.18 0.18 0.15 0.17 0.18 0.18 0.27 0.21 Goodyear Dunlop Tires North America Ltd 153.83 0.20 3.36 0.16 0.16 0.15 0.17 0.19 International Imaging 0.02 0.02 0.02 0.0 5 0.02 0.02 0.02 0.03 Noco Energy Corp 94.48 16.11 0.32 0.10 0.17 0.05 0.03 0.03 Cello

- Pack Corporation of Buffalo 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Whiting Door Manufacturing Corp 0.01 0.02 0.01 0.01 0.01 0.01 0.01 0.01 General Mills Operations LLC * 0.35 0.39 0.07 0.11 0.26 0.09 0.00 Buffalo State College 73.75 30.43 35.91 6.73 0.09 0.09 4.47 0.00 Concord Compressor Station * 0.00 0.12 0.00 0.01 0.01 0.02 0.10 0.00 Lackawanna Plant

- Republic Steel * 0.43 0.46 0.29 0.37 0.39 0.41 0.36 0.00 E I Dupont Yerkes Plant * 0.01 0.00 0.00 0.06 1.49 0.34 0.10 0.00 Tonawanda Coke Corp * 353.70 285.85 127.22 378.02 378.01 347.30 401.39 0.00 Buffalo Terminal 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Unicell Body Company Inc 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Sunoco Tonawanda Terminal 0.07 0.73 0.05 0.03 0.02 0.00 0.00 0.00 Henkel Corporation 0.01 0.01 0.01 0.00 0.00 QG Printing Corp 0.04 0.03 0.03 0.00 Arcelormittal Lacakawanna LLC 0.44 0.36 0.09 0.00 0.00 Great Lakes MDF 0.00 0.00 0.00 0.00 Quebecor World Buffalo Inc 44.89 0.04 0.03 0.00

Total 11,608.58 7,422.80 6,401.07 6,670.81 4,924.32 3,270.62 3,860.93 3,456.09 * 2014 emission statement is not technically complete (either data not entered or data may change)

15Fi gure 2 : Sources Emitting Greater Than 40 tons/year of SO 2 near Huntley

16Ta ble 7: SO 2 Emissions ( tons): Niagara County Point Sources Facility 2007 2008 2009 2010 2011 2012 2013 2014

Somerset (aka AES Somerset LLC) 4,261.62 3,937.74 5,076.81 7,618.01 10,024.21 5,653.36 5,722.67 4,817.21 Globe Metallurgical Inc 0.03 107.38 521.85 601.98 699.01 633.31 572.73 Niagara Generating Facility 544.30 925.70 451.80 1.55 0.00 7.22 48.92 244.03 Covanta Niagara LP 137.67 163.68 145.84 119.68 90.02 87.76 130.91 225.21 Model City Energy Facility 8.29 23.81 25.22 25.91 24.79 25.06 16.55 14.21 TAM Ceramics LLC 0.52 6.45 3.36 0.00 7.73 7.93 6.67 5.28 T N Gas Pipeline CO Comp

. Stat

. 230

- C 0.23 0.14 0.03 0.02 0.00 0.32 4.34 4.31 Metaullics Systems Division of Pyrotek Inc 0.00 7.07 5.94 2.49 2.69 1.60 Dupont (aka Chemours) 0.23 0.22 0.71 0.79 0.03 0.02 0.02 0.19 GM (aka Delphi Thermal Systems) 0.00 0.08 0.00 0.00 0.08 0.09 0.10 0.10 Occidental Chemical Corp

- Niagara Plant 0.00 0.01 0.01 0.00 0.00 0.00 0.40 0.07 Lockport Cogeneration Facility 21.32 0.39 0.36 0.00 0.03 0.07 0.02 0.05 Durez Niagara 0.00 0.00 0.20 0.00 0.00 0.03 0.03 0.03 Prestolite Electric NY Inc 0.02 0.02 0.62 0.03 Vandemark Chemical Inc 0.01 0.07 0.05 0.70 0.07 0.07 0.03 0.02 Washington Mills Electro Minerals 0.03 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Modern Landfill Inc 0.25 0.19 0.03 0.33 4.63 0.23 0.05 0.00 Fortistar North Tonawanda Inc 0.24 0.00 0.00 0.70 0.33 1.27 0.91 0.00 Goodyear Chem Plant 0.00 0.00 0.01 0.00

Total 4,974.71 5,058.54 5,818.91 8,290.17 10,759.85 6,484.94 6,567.63 5,885.08

Fi gure 3 : Sources Emitting Greater Than 40 tons/y ea r of SO 2 near Somerset

17A irports also contribute to the total SO 2 emissions, and are accounted for in the non

road mobile inventory. The airport portion of the non

- road inventory includes aircraft and ground support equipment. 2011 airport emissions are listed in Tables 8, 9 and 10

. With the exception of Buffalo Niagara International Airport, which emitted 41.3797 tons of SO 2 in 2011, the emissions from airports is very small.

Table 8 : Cattaraugus County Airports: 2011 Emissions Inventory Airport SO 2 (tons) Cattaraugus County

– Olean Airport 0.1900 Great Valley Airport 0.0511 Randolph Airport 0.0200 South Dayton Airport 0.0126 Giermek Executive Airport 0.0028 Olean General Heliport 0.0013 Hedge Hop Field Airport 0.0005 Reiss Game Farm Airport 0.0005 Berdick Field Airport 0.0004 Neverland Airport 0.0004 Ultralight Port Airport 0.0004 Campbell Field Airport * Total 0.28 00
*No data available

18Ta ble 9 : Erie County Airports: 2011 Emissions Inventory Airport SO 2 (tons) Buffalo Niagara International Airport 41.3797 Buffalo Airfield 0.3817 Akron Airport 0.3763 Buffalo Lancaster Regional Airport 0.3123 Hamburg Inc Airport 0.0837 Clarence Aerodrome 0.0694 Heussler Hamburg Airport 0.0481 Gowanda Airport 0.0251 Potoczak Airport 0.0022 Bertrand Chaffee Hospital Heliport 0.0013 Buffalo General Hospital Heliport 0.0013 Erie County Medical Center Heliport 0.0013 Gibralter Heliport 0.0013 Mercy Hospital Heliport 0.0013 South Buffalo Mercy Hospital Heliport 0.0013 Tennessee Gas Nr 2 Heliport 0.0013 Women and Childrens Hospital Heliport 0.0013

Woodlawn Beach State Park Heliport 0.0013 Ciszak Airport 0.0007 Gentzke Aeronautical Park Airport 0.0007 High Acres Airport 0.0007 Merkle Airport 0.0007 TTT Air 0.0007 Donnelly’s Airport 0.0006 Evans Airways Airport 0.0006 Hilltop Airport 0.0006 Knox Landing Airport 0.0006 Mesmer Airport 0.0006 Basher Field 0.0001 Treichler Farm Airport 0.0000 Total 42.6966

19T able 10: Niagara County Airports: 2011 Emissions Inventory Airport SO 2 (tons) Niagara Falls International Airport 1.5598 Royalton Airport 0.0420 North Buffalo Suburban Airport 0.0250 Hollands International Field Airport 0.0173 Best Western Red Jacket Inn Heliport 0.0013 Niagara Falls Memorial Parking Ramp Heliport 0.0013 Rainbow Air Heliport 0.0013 Ross Heliport 0.0013 St. Mary’s Heliport 0.0013 Flying F Airport 0.0006 Smith Airport 0.0006 Hibbards Airport 0.0005 Pendleton Airpark 0.0005 Shear Airport 0.0005 Taylor Johnson Airport 0.0005 Bassett Field Airport 0.0000 Bent

- Wing Airport 0.0000 Cambira Airport * Colonial Airport * Lockport Cambria Airport * Olcott Newfane Airport * Total 1.6538

* No data available

20

### Factor 3: Meteorology

M eteorological data for AERMOD were processed using the AERMET meteorological pre

- processor along with AERMINUTE and AERSURFACE. Five years of meteorological data (2010

- 2014) from Buffalo Niagara International Airport were used to obtain the surface data, and upper air data from the same location were used to obtain the required vertical profiles. After 5 years of data were processed, both surface and upper air meteorological files were truncated to dates that fit the hourly emissions records (January 1, 2012 to December 31, 2014)

.

A n analysis was undertaken to estimate the degree to which the impacts of Huntley and other nearby SO 2 sources are reflected in the measurements from the Tonawanda II

mon itor. Five

- years of hourly wind data from Buffalo Niagara International Airport and Niagara Falls International Airport were used to create wind roses. The two wind roses are very similar at both locations with winds from the southwest quadrant being strongly dominant.

Fi gure 4 : Wind Roses from Buffalo Niagara International Airport and Niagara Falls International Airport

T he similarity between the wind roses from the two locations, as well as the generally flat terrain in the area, give confidence that the winds in the Tonawanda area follow a similar pattern.

21A pollution rose was created using a combination of hourly SO 2 concentrations from the Tonawanda II monitor and hourly winds from the Buffalo Niagara International Airport.
Figure 5 : SO 2 Pollution Wind Rose for Tonawanda II Monitor

T hi s rose shows a strong influence from H untley and nearby SO 2 sources on the SO 2 levels at the ambient monitor site. H untley and the other nearby significant SO 2 sources are located to the southwest and south

- southwest of the monitor site at a distance of 2

- 5 km.

A verage SO 2 concentrations at the monitor when winds are from the southwest or south

- southwest are over 3 ppb. By comparison, average SO 2 concentrations for winds from all quadrants other than southwest are near or below 2 ppb. W hen winds are from the south

- southwest (195° to 225°), higher SO 2 concentratio ns correlate with higher wind speeds. This provides additional evidence that the impacts of the nearby sources are reflected in the monitor data. The stronger winds give the SO 2 plumes less time to disperse before they arrive at the monitor site, resulting in higher impacts.

F or Somerset, f ive years of meteorological data (20 10

- 2014) from Niagara Falls I nternational Airport were used to obtain the surface data, and upper air data from
22B uffalo Niagara Internatio nal Airport were used to obtain the required m orning sounding profiles. After 5 years of data were processed, both surface and upper air meteorological files were truncated to dates that fit the hourly emissions records (January 1, 201 1 to December 31, 201 3 ). Winds are predominantly from the southwes t.

T he hourly SO 2 data from the Niagara Falls monitor for the period 2010 – 2012 was processed to obtain 3

- year averages of the 99th percentile concentrations by season and hour

- of

- day pursuant to EPA’s 2011 Memorandum by Tyler Fox entitled “Additional Clarification Regarding Application of Appendix W Modeling Guidance for the 1

- hour NO 2 National Ambient Air Quality Standard”. The processed data were included in AERMOD in order to add background values to calculated SO 2 impacts. Note that the Niagara Falls monitor discontinued measuring SO 2 beyond 2012 making this period the most recent SO 2 background data for our modeling analysis. The more urban setting of the monitor as compared to the facility as well as the data being a year older when trends have be en coming down for SO 2 makes this a conservative choice of a representative background data. The location of the ambient monitor relative to Somerset Station is shown in Figure 3.

DE C determined that it was not necessary to include any nearby sources in S omerset’s modeling analysis because the nearest facility emitting greater than 40 tons/year is located more than 40 km from Somerset

. Additionally, the background monitor selected is conservative and reflects the contributions of the nearby sources to the ambient SO 2 concentrations.

A complete discuss ion of meteorology can be found in the modeling reports for Huntley and Somerset included in this report as Appendix A and Appendix B respectively.

23

### Factor 4: Geography and Topography

T he Niagara Frontier is most commonly referred to as the land bordering the eastern Niagara River and southern shores of Lake Erie and Lake Ontario and is part of the region known as Western New York State. The Niagara Frontier also forms the eastern part of the Great Lakes North Coast, while its southeastern boundary forms what is known as ski country.

T here are no mountain ranges or other air basin boundaries that have a distinguishable effect on the Niagara Frontier.

24

### Factor 5: Jurisdictional Boundaries

T he Un ited States Office of Management and Budget (OMB) delineates metropolitan and micropolitan statistical areas according to published standards that are applied to Census Bureau data. The general concept of a metropolitan or micropolitan statistical area is that of a core area containing a substantial population nucleus, together with adjacent communities having a high degree of economic and social integration with that core. Currently delineated metropolitan statistical areas (MSAs) and micropolitan statisti cal areas (mSAs) are based on application of 2010 standards ( which appeared in the Federal Register on June 2010) to 2010 Census and 2006

- 2010 American Community Survey data. Current MSA and mSA delineations were announced by OMB effective February 2013.

A djacent M SAs and mSAs may become the components of a set of complementary areas called Combined Statistical Areas (CSAs). Historically, EPA has used the CSA as the starting point for consideration when developing designation recommendations. For purposes of this revised designation recommendation, DEC is evaluating the Buffalo

Cheektowaga, NY CSA, which is comprised of the Buffalo

- Cheektowaga

- Niagara Falls, NY MSA (Erie and Niagara Counties) and the Olean, NY mSA (Cattaraugus County).

25

### Recommendations

D EC recommends that the Buffalo

- Cheektowaga, NY CSA ( Cattaraugus, Erie and Niagara Counties ) be designated “attainment” for the 1

- hour SO 2 NAAQS because :

1. de sign values calculated from actual monitoring data demonstrate that all monitors in both Erie and N iagara counties, as well as the next closest monitors located in Chautauqua, Monroe and Steuben counties, are well below the NAAQS of 75 ppb and trending downward , and

2. di spersion modeling performed to assess the attainment status of the area around Huntley and Somerset, in the context of EPA’s 1- hour SO 2 Data Requirements Rule, demonstrates that Huntley and Somerset do not cause or contribute to a violation of the 1

- hour SO 2 NAAQS

.

26

### APPENDIX A: Air Quality Modeling for Huntley Generating Station

27

# Air QualityModeling

for Huntley Generating Station

P repared by Impact Assessment and Meteorology Se ction New York State Department of Environmental Conservation

Ju ly 2015TABLE OF CONTENTS

1 .0 INTRODUCTION

2.0 FACILITY DESCRIPTION

2.1 FACILITY LOCATION

2.2 SOURCE P ARAMETERS AND EMISSION RATES

3.0 AIR DISPERSION MODELING ANALYSIS

3 .1 METEOROLOGICAL DATA

3.2 RECEPTOR GRID

3.3 AMBIEN T BACKGROUND DATA

4.0 MODELING RESULTS

5.0 CONCLUSIONS
Appendix A – Modeling Files (on disc)1.0 INTRODUCTION

T he purpose of this document is to present the results of the modeling per formed

to assess the attainment st atus of the area around Huntley Generating Station (H untley)

in the context of the 1

- hour SO 2 Data Requirements Rule (DRR).

T he air dispersion modeling methodology that was followed is based on policies and procedures contained in the USEPA Guideline on Air Quality Models (40 CFR Appendix W) and the New York State Department of Environmental C onservation’s (NYSDEC) Air Quality Modeling Procedures as outlined in DAR

- 10 / NYSDEC G uidelines
on Dispersion Modeling Procedures for Air Quality Impact Analysis, m odified by the SO 2 NAAQS Designations Modeling Technical Assistance Document (Modeling TAD) where
applicable.

T he steps taken to conduct the air

- dispersion modeling analyses are summarized below:

• Compile information on the parameters and cha racteristics for H untley ;

• Obtain and prepare hourly emissions data for HGS for the period 2012

- 2014 ;

• Develop a comprehensive receptor grid to capture the maximum offsite impacts
from the main stack;

• P rocess three years of meteorological data (as available from a local, representative meteorological station) using the meteorological pre

- processor AERMET along with AERMINUTE and AERSURFACE;

• Ob tain and prepare appropriate SO 2 background data from the nearest
representative monitor ;

• Complete an ambient air quality modeling analysis using USEPA’s regulatory
dispersio n model, AERMOD (version 14134);

• Summarize the results in tabular format and compare the results with the 1

- hour

SO 2 ambient air quality standard.The n ext s ection provides a description of the facility and the emissions included in the modeling. Model selection and the methodology used in the modeling are described in Section 3. The modeling results are presented in Section 4.2. 0 FACILITY DESCRIPTION

T he Huntley Power Station is located on the shore of the Niagara River in the Town of Tonawanda, Erie County, NY. The electrical generating facility consists of two
pulverized coal, dry

- bottom, tangential

- fired boilers that primarily fire sub

- bituminous coal and can produce up to 400 megawatts of electricity. The boiler s fire distillate oil
during various startup modes. Boilers 67 and 68 have a maximum heat input of 1836

MM Btu/hr each and exhaust combustion gases through a common stack. Steam from
each boiler is used to power a dedicated steam turbine

- generator set that is capable of
generating 200 megawatts of electricity. Combustion Engineering manufactured unit 67 in 1957 and unit 68 in 1958. Units 67 and 68 are tangentially fired dual furnace boilers, where there are two separate fire boxes and a common primary steam header for each
boiler. For each boiler one furnace produces the superheated steam while the other

furnace creates reheat steam. Both units use fabric filters to control particulate

emissions , dry sorbent injection to control acid gases, selective noncatalytic reduction (SNCR) to control nitrogen oxide emissions, and activated carbon injection to control
mercury emissions

. Each emission control system is used as needed to meet the
appropriate emission limits.2.1 FACILITY LOCATION

H untley Generating Station is located approximately 10.5 km north

- north we st of
Buffalo, NY. The plant is on the east bank of the Niagara River, adjacent to the southern

end of Grand Island. Figure 2

- 1 displays an aerial i mage of the area around Huntley Generating Station , with the facility’s property outlined in yellow

. Figure 2

- 2 is a photo of the facility, showing the operating stack on the left. The other stack in the photo is no longer in use. The Universal Transverse Mercator (UTM83) coordi nates of the
operational stack are approximately 668784.63 E, 4759614.9 N (Zone 17). The base

elevation of the stack is 174.9 m.

Fi gure 2 -1 : Aerial Photograph of Huntley Generating StationFigure 2 -2 : Photograph of Huntley Generating StationFigure 2.3 – Detailed Aerial View2.2 SOURCE PARAMETERS AND EMISSION RATES

S ource parameters and emission rates for the two boilers at the facility were
obtained from Roger Caiazza of the Environmental Energy Alliance of New York

.

T he hourly values of SO 2 emission rates, stack flow rates and stack temperature

for 201 2- 201 4 were received in three excel files and subsequently converted into units and file format appropriate for AERMOD use. The stack height is 106.7 m, and the exit

diameter of the stack is 5.72 m.2.3 BUILDINGS and FENCELINE

B uilding height infor mation was obtained from Patrick Yough, Environmental Manager at NRG

. The building footprints used for downwash calculations, as well as the
fenceline, are based on the Google Earth image of the facility. BPIP

- Prime was run to prepare the building files needed for AERMOD run.

Fi gure 2 -4 : Building Layout and Fenceline used for Analysis3.0 AIR DISPERSION MODELING ANALYSIS

T he Modeling TAD describes two types of modeling: using the allowable emission rate along with 5

- years of meteorological data and GEP stack height, or, as a refinement,

3- years of actual hourly emissions data along with 3

- years of concurrent meteorological data, using the true stack height regardless of GEP. For this modeling analysis, the second option was exercised. Actual hourly emissions data obtained from the facility were matched with 3 years of concurrent surface and upper

- air meteorological data from

Buffalo Niagara International A ir port to run AERMOD version 14134

.3.1 METEOROLOGICAL DATA

M eteoro logical data for AERMOD were processed using the AERMET (version 14134) meteorological pre

- processor along with AERMINUTE (version 14337) and AERSURFACE (version 13016). Five years of meteorological data (20 10- 2014) from the

Buffalo Niagara I nternational Airport were used to obtain the surface data, and upp er air

data from the same location were used to obtain the required vertical profiles. After 5

y ears of data were processed, both surface and upper air meteorological file s were truncated to dates that fit the hourly emissions records (1/1/2012 to 12/31/2014 ).

P rior to processing the meteorological data with AERMET, the land -use within 1 km of the meteorological tower at Buffalo Niaga ra International Airport was analyzed using the AERSURFACE pre

- processor. AERSURFACE uses land cover data from the

National Land Cover Data (NLCD) 1992 database to determine three key surface parameters needed for modeling: surface roughness albedo, and the Bowen ratio. For this modeling, the 1

- km radius circular area centered at the meteorological station site

was divided into 12 equal 30

- degree sectors. For the Bowen ratio calculations , the land

use values can be linked to three categories of surfac e moisture corresponding to
average, wet, and dry conditions – depending on the site and meteorological data period

. For this site and data period, the “average” surface moisture option was applied.

T he AERSURFACE results are used as input into the AERMET meteorological
data processor. Additionally, 1

- minute ASOS wind data, collected at the Buffalo airport
meteorological tower, were processed using the AERMINUTE pre

- processor for

AERMET. Figure 3

- 1 presents a wind ros e for the 3 years of meteorological data processed for the modeling analysis. Figure 3

- 2 shows the relative locations of Huntley Generating Station, the meteorological data collection site, and the ambient background

monitor (see Section 3.3 ) used in the modeling.Figure 3 -1 : Wind Rose for Buffalo Niagara International AirportFigure 3 -2: Locations of Facility, SO 2 Monitor, and Weather Station3.2 RECEPTOR GRID

A comprehensive po lar receptor grid extending to 20 km from the Huntley Generating Station was used in the AERMOD modeling to assess maximum ground

- level

SO2 concentrations. The receptor grid consisted of the following receptor spacing :

• 1 00 m spacing extending from the source to 2 km; • 250 m spacing extending from 2 km to 5 km; • 500 m spacing extending from 5 km to 10 km; and • 1000 m spacing extending from 10 km to 20 km

R eceptors were placed on 36 radials 10 degrees apart and the grid was centered on the
emission source. Receptors within the Huntley fenceline were eliminated and special
receptors were placed along the fenceline at ever y 25 m. This grid contained a total of

1 369 receptors. The base elevation and hill scale parameters for all receptors were assigned using AERMAP (version 11103) based on data obtained from the National Elevation Dataset

website. The receptor grid used in modeling is shown in Figure 3-3 below

.Figure 3 -33.3 AMBIENT BACKGROUND DATA

A n analysis was undertaken to estimate the degree to which the impacts of Huntley and other nearby SO 2 sources are reflected in the measurements from the T onawanda II (also known as Tonawanda – Brookside Terrace) ambient air monitoring station. Five

years of hourly wind data from Buffalo

- Niagara International Airport and Niagara Falls
International Airport were used to create wind roses. The two wind roses are very similar (Fig. 3

- 4) -- at both locations, winds from the southwest quadrant are strongly dominant. The similarity between the wind roses from the two locations, as well as the generally flat

terra in in the area, give confidence that the winds in the Tonawanda area follow a similar pattern. A pollution rose (Fig. 3

- 5) was created using a combination of hourly SO 2 concentrations from the Tonawanda II monitor and hourly winds from the Buffalo

- Niagara International Airport. This rose shows a strong influence from Huntley and nearby SO 2
sources on the SO 2 levels at the ambient monitor site. Huntley and the other nearby significant SO 2 sources are located to the southwest and south

- southwest of the monitor

site at a distance of 2

- 5 km (ma p, Fig. 3 -7 ). Average SO 2 concentrations at the monitor

when winds are from the southwest or south

- southwest are over 3 ppb. By comparison, average SO 2 concentrations for winds from all quadrants other than southwest are near
or below 2 ppb. Table 3

- 1 shows that when winds are from the south

- southwest (195° to 225°), higher SO 2 concentrations correlate with higher wind speeds. This provides additional evidence that the impacts of the nearby sources are reflected in the monitor data. The stronger winds give the SO 2 plumes less time to disperse before they arrive at
the monitor site, resulting in higher impacts.Fig. 3 -4 : Wind Roses from Buffalo and Niagara Falls airports

Fi g. 3

- 5: SO 2 pollution rose for Tonawanda II monitor site ( Buffalo airport winds )Labels indicate rounded average SO 2 concentration for the indicated wind direction. Color bars indicate the frequency of the indicated concentration for that wind

direction.

Ta ble 3 -1 : Tonawanda 2012

- 2014 SO 2 concentration as a function of wind speed

and direction

SO 2 Concentration Wind Direction (degree)
0 30 60 90 120 150 180 210 240 270 300 330 Wind Speed

Kno ts 0

- 1 1.76 1.35 1.77 1.65 1.67 2.47 1.48 1.8 1.53 1.59 2 1.45
1

- 4 1.68 1.42 1.56 1.44 1.35 1.41 1.61 1.83 2.55 1.94 1.87 1.48
4

- 7 2.38 1.54 2.22 2.12 1.94 1.8 2.12 2.76 2.96 2.24 2.16 1.68
7

- 11 3.01 1.85 2.53 2.73 2.7 1.57 2.14 3.97 3.23 2.55 1.82 1.52
11

- 17 2.93 1.3 1.5 2.55 4.49 2.85 2.9

S ince the monitor data already to a large degree reflect the contributions of Huntley and nearby sources to the SO 2 concentration, it was not necessary to include emiss ions from sources other than Huntley in the modeling. All of the available monitor data was used in calculating the seasonal/hourly background values, including the time per iods when the nearby sources were impacting the monitor. As such, the modeled

concentrations , which include seasonal/hourly 99 th percentile background, can be
expected to be highly conservat ive

.

T he hourly SO 2 data from the Tonawanda II monitor for the period 201 2 - 201 4
were processed to obtain 3- year average s of the 99 th percentile concentr ations by season

and hour

- of

- day . These calculations were made according to the method specified in
EPA’s 2011 Memorandum by Tyler Fox , “ Additional Clarification Regarding Application of Appendix W Modeling Guidance for the 1

- hour NO 2 Nation al Ambient Air Quality

Standard”. Missing data were treated conservatively by using the first

- highest value (rather than the second

- highest) for season/hour combinations with less than 82.2 % data
completeness

. The processed data (shown in figure 3-6 ) were included in the AERMOD
input file in order to add background values to calculated SO 2 impacts.Figure 3 -6:

T he design value, depicted here by the gray line, is the mathematically determined pollutant concentration at a particular site that is used for comparison to the National Ambient Air Quality Standard (NAAQS) in order to assure attainment. The design value
may be calculated based on ambient measurements observed at a local monitor over a
three year period, or on model estimates.F igure 3

- 7: Map of Monitor Location relative to SO 2 Sources4.0 MODELING RESULTS

T able 4- 1 shows AERMOD calculated impacts that inc lude seasonally

- based hourly background concentrations.

Ta ble 4 -1 : Modeled 3

- year Average Impacts

Pollutant Averaging
period 4th highest
concentration,
Huntley

contribution 4 th highest

concentration
, including
background SO2 NAAQS ( ppb )

SO 2 1 hour 44.1 ppb (115.5 μg/m 3 ) 54.3 ppb ( 142.3 μg/m 3 ) 75

F i gure 4-1 shows the nearby imp acts of the facility (not including background) on

the 1

- hour SO 2 design value over the 2012

- 2014 period in μg/m3 . The maximum im pact is located at the southeastern boundary of the facility’s property.Figure 4 -1 : Modeled Impact of Huntley on 1

- hour SO 2 Design Value5.0 CONCLUSIONS

Th e m od e ling performed demonstrates that Huntley Ge nera ting Sta tion does not

ca u se or c ontribut e to a viol a tion of th e 1- hour SO 2 NAAQS. Therefore, an a tt a inm e nt

d es ign a tion for the area around the sta tion is r ecomm e nd ed.

### APPENDIX B: Air Quality Modeling for Somerset Station

28

# Air Quality Modeling for Somerset Station

P repared by Impact A ssessment and Meteorology S ection New York State Department of Environmental Conservation

J uly 2015T ABLE OF CONTENTS

1 .0 INTRODUCTION

2.0 FACILITY DESCRIPTION

2.1 FACILITY LOCATION

2.2 SOURCE P ARAMETERS AND EMISSION RATES

3.0 AIR DISPERSION MODELING ANALYSIS

3 .1 METEOROLOGICAL DATA

3.2 RECEPTOR GRID

3.3 AMBIEN T BACKGROUND DATA /NEARBY SOURCES

4.0 MODELING RESULTS

5.0 CONCLUSIONS

6 .0 REFERENCES
Appendix A – Modeling files (on disc)1.0 INTRODUCTION

T he purpose of this document is to present the results of the modeling performed

to assess the attainments status of the area around Somerset Station in the context of

the 1

- hour SO 2 Data Requirements Rule (DRR). The air dispersion modeling methodology that was followed is based on policies and procedures contained in the USEPA Guideline on Air Quality Models (40 CFR Appendix W) and the New York State Department of Environmental C onservation’s (NYSDEC) Air Quality Modeling Procedures as outlined in DAR

- 10 / NYSDEC G uidelines
on Dispersion Modeling Procedures for Air Quality Impact Analysis, m odified by the SO 2 NAAQS Designations Modeling Technical Assistance Document (Modeling TAD) where
applicable.

T he steps taken to conduct the air

- dispersion modeling analyses are summarized

below:

• Compile information on the parameters and characteristics for Somerset Unit 1;

• Obtain and prepare hourly emission s data for Somerset Unit 1 for the period 2011

-
2013 ;

• Develop a comprehensive receptor grid to capture the maximum offsite impacts
from the main stack;

• P rocess five years of meteorological data (as available from a local, representative meteorological station) using t he meteorological pre

- processor AERMET along
with AERMINUTE and AERSURFACE;

• Ob tain and prepare appropriate SO 2 background data from the nearest
representative monitor ;

• Complete an ambient air quality modeling analysis using USEPA’s regulatory
dispersio n model, AERMOD (version 14134);

• Summarize the results in tabular format and compare the results with the 1

- hour

SO 2 ambient air quality standard.The n ext s ection provides a description of the facility and the emissions included
in the modeling. Model selection and the methodology used in the modeling are described in Section 3. The modeling results are presented in Section 4, and references are provided in Section 5.2. FACILITY DESCRIPTION

S omerset Generating Station, located in Somerset, NY, is a 675 megawatt (MW) electric generating facility. The primary fuels combusted by the main boiler are bituminous coal and petroleum coke (petcoke). The coal may contain a latex dust suppressant as
supplied. Associated with the boiler is a coal handling system (unloading and conveying

coal and petroleum coke, etc.), a No. 2 fuel oil system (tanks and piping) which is used for startup and flame stabilization, a limestone handling system (unloading and conveying, etc.), and other miscellaneous sources and activities related to the operation of an electric generating station. The station also includes two oil fired boilers that are

used for start

- up of the main boiler and one diesel

- fired emergency electric generator.

2. 1 FACILITY LOCATION

S omerset Generating Station is located approximately 35 miles north

- northeast of
Buffalo, NY and 50 miles west

- northwest of Rochester, NY. The plant is on the south shore of Lake Ontario. Figure 2

- 1 displays an aerial image of the area around Somerset Generating Station. Universal Transverse Mercator (UTM83) coordinates of the center of
the plant are approximately 694200E, 4803100N (Zone 17). The base elevation of the main stack is 292 feet (89 m). Figure 2 -2 shows a closer areal look at the facility and
buildings layout. Both photos were provided to us by Environmental Resources Management (ERM).Figure 2

- 1 Aerial P hotograph of Somerset Generating StationFigure 2

- 2 Somerset B uildings L ayout - Areal V iew ; Building key: 1

- Boiler buiding; 2

- Turbine building; 3- Administation building; 4

- Water prep; 5

- Water treatment; 6

- EPRI; 7

- ESP; 8

- ID fan; 9

- 16 tiers of FDD building; 17

- LCRH; 18

- CCH2.2 SOURCE PARAMETERS AND EMISSION RATES

S ource parameters and emission rates for the Main boiler at the facility (Uni t 1)

were obtained from John Marabella, Environmental Director at the Upstate New York

Power Producers. The hourly values of SO 2 emission rates, stack flow rates and stack temperature for 2011

- 2013 were received in three excel files and subsequently c onverted into units and file format appropriate for AERMOD use

. For hours where the provided files contained missing data (N/A values) numbers were substituted with following criteria:

1) I f all three variables (SO 2 emission rate, stack flow and temperature) were ‘ N/A ’ it

was assumed the unit did not operate and all three were replaced by zeros. 2) If any of the three variables was measured (not ‘N/A’) it was assumed that only the CEM instrument was off and all three were replaced with the mos t conservative (maximum) value measured over the three years ( SO 2 emission of 6010.46 lb/hr and corresponding flow rate of 108679.2 kscfh and T=123.3F

F or quality assessment purposes, the hourly emissions data were reviewed and compared to Clean Air Market Data (CAMD). The Somerset Unit 1 stack height is 186.84

m and the stack exit diameter is 8.129 m.

T here are four additional sources of SO 2 emissions at Somerset: two oil

- fired
auxiliary boilers and one diesel

- fueled emergency engine. In accordance with the facility’s
Title V permit, the auxiliary boilers do not operate when the main boiler is online and therefore can be excluded from cumulative modeling with the Unit 1 boiler. The emergency generator testing can also be excluded from the modeling based on U SEPA guidance provided in the 1 March 2011 memorandum “ A dditional Clarification Regarding Application of Appendix W Modeling Guidance for the 1

- hour NO 2 National Ambient Air Quality Standard” for intermittent sources such as emergency generators. As noted in the clarification letter this interim guid a nce can be extended to 1

- hour SO 2 applications

. Therefore, both auxiliary boilers and emergency generators were excluded from this
modeling.2.3 BUILDINGS and FENCELINE

Building infor mation was obtained from a BPIP

- Prime input file received fro m John

Marabella . T he building locations were verified based on Google Earth image of the
facility as was the fenceline

. BPIP

- Prime was re

- run to prepare the building files for

AERMOD run. Struct ures included in Somerset BPIP

- Prime run and GEP analysis are
shown in Figure 2

- 3.Figure 2-3 Structures I ncluded in Somerset GEP A nalysis3.0 AIR DISPERSION MODELING ANALYSIS

The Modeling TAD describes two types of modeling: using the allowable emission rate along with 5 years of meteorological data and GEP stack height, or, as a refinement,

3 years of actual hourly emissions data along with 3 yea rs of concurrent meteorological
data along with the true stack height regardless of GEP. In this modeling analysis

, AERMOD version 1 4134 was run for the following two scenarios :

• Three years of hourly emissions data obtained from the facility (as described in Section 2.2) were matched with 3 years of concurrent meteorologi cal data from Niagara Falls/ Bu ffalo airports and modeled with the actual stack height (186.84m).

• A f ixed emission rate based on a permit limit to comply with the Mercury and Air Toxics Standards (MAT S ) was modeled with 5 years of meteorological dat a and

the GEP stack height of 170.36m. Modeling parameters and emission rates for

Unit 1 stack were obtained from 26 April 2011 effective Title V permit (9

- 2938

- 00003/00002) . This included the SO 2 emission rate of 1,256 lb/hr, stack exhaust
temperature of 405.15K an d exit velocity 16.11m/s.

3.1 METEOROLOGICAL DATA

Meteoro logical data for AERMOD were processed using the AERMET (version 14134) meteorological pre

- processor along with AERMINUTE (version 14337) and AERSURFACE (version 13016). Five years of meteorological data (20 10

- 2014) from the
Niagara Falls I nternational Airport were used to obtain the surface data, and upper air

data from Buffalo

- Niagara Internatio nal Airport were used to obtain the required morning sounding profiles. After 5 y ears of da ta were processed, both surface and upper air
meteorological file s were truncated to dates that fit the hourly emissions records (1/1/2011 to 12/31/2013).
Prior to processing the meteorological data with AERMET, the land

- use within 1 km of the meteorologic al tower at Niagara Falls International Airport was analyzed using the AERSURFACE pre

- processor. AERSURFACE uses land cover data from the

National Land Cover Data (NLCD) 1992 database to determine three key surfaceparameters needed for modeling: surface roughness , albedo and the Bowen ratio. For this modeling, the 1

- km radius circular area centered at the meteorological station site

was divided into 12 equal 30

- degree sectors. For the Bowen ratio calculations , the land

use values can be linked to three categories of surface moisture corresponding to
average, wet, and dry conditions – depending on the site and meteorological data period

. For this site and data period, the “average” surface moisture option was applied. The AERSURFACE results are used as inpu t into the AERMET meteorological
data processor. Additionally, 1

- minute ASOS wind data, collected at the Niagara Falls
meteorological tower, were processed using the AERMINUTE pre

- processor for

AERMET. Figure 3

- 1 presents a wind rose for the 3 years of meteorological data processed for the modeling analysis . Figure 3

- 2 shows the relative locations of Somerset Generating Station, the meteorological data collection site, and the ambient background

monitor (see Section 3.3 ) used in the modeling.Figure 3

- 1 Wind rose f or Niagara Falls International A irport ( 2011

- 2013 )Figure 3 -2 Relative L ocations of Somerset Generating Station, Niagara Falls International Airport, and SO 2 Ambient M onitor3.2 RECEPTOR GRID

A comprehensive po lar receptor grid, extending to 20 km from the Somerset Generating Station was used in the AERMOD modeling to assess maximum ground

- level

SO 2 concentrations. T he receptor grid consisted of the following receptor spacing :

• 1 00 m spacing extending from the source to 2 km;

• 250 m spacing extending from 2 km to 5 km; • 500 m spacing extending from 5 km to 10 km; and • 1000 m spacing extending from 10 km to 20 km
Receptors were placed on 36 radials 10 degrees apart and the grid was centered on the
Unit1 emission source. Recept ors within the Somerset fenceline were eliminated and special receptors were placed along the fence line at ever y 50 m. This grid contained a

total of 1723 receptors. The base elevation and hill scale parameters for all receptors were assigned using

AERMAP (version 11103) based on data obtained from the National Elevation Dataset

website. The receptor grid used in modeling is shown in Figure 3-3.Figure 3

- 3 R eceptors used in the Somerset Air Dispersion Modeling analysis3.3 AMBIENT BACKGROUND DATA

The hourly SO 2 data from the Niagara Falls monitor for the period 2010 – 2012

was processed to obtain 3- year average s of the 99th percentile concentr ations by season

and hour

- of

- day following EPA’s 2011 Memorandum by Tyler Fox “ Add itional Clarification Regarding Application of Appendix W Modeling Guidance for the 1

- hour NO 2 Nation al Ambient Air Quality Standard”. The proce ssed data (shown in Figure 3 -4 ) were included in AERMOD in order to add background values to calculated SO 2 impacts. Note that the Niagara Falls monitor discontinued measuring SO 2 beyond 2012 making this period the

most recent SO 2 background data for our modeling analysis. The more urban setting of the monitor as compared to the facility as well as the data being a year older when trends have been coming down for SO 2 makes this a conservative choice of a representative
background data.

Fi gure 3 -4 Niagara Falls One

- hour SO2 concentrations for 2010

- 2012 period. The design

value, depicted here by the gray line (DV) , is the mathematically determined pollutant concentration at a particular site that is used for comparison to the National Ambient Air Quality Standard (NAAQS) in order to assure attainment. The design value may be calcul ated
based on ambient measurements observed at a local monitor over a three year period, or on model estimates.F igure 3 -5 shows a map with relative locations of Somerset Generating Station,

the Niagara Falls SO 2 monitor as well as any Title V facilities emitting more than 40 tons/year of SO 2 within a 50 km radius of Somerset Station

. We determined that it was

not necessary to include any nearby sources in our modeling analysis si nce the nearest facility emitting greater than 40 tons/year is located more than 40 km from Somers et

Statio n. In addition, the background monitor selected is conservative and reflects t he

contributions of the n earby sources to the ambient SO 2 concentration s

.

Fi gure 3

- 5 Niagara Falls Monitor Location Relative to Sources Emitting more than 40 tons/yr of SO2 within 50 km radius of Somerset Generating Station

.4.0 MODELING RESULTS

T able 4- 1 shows AERMOD c alculated impacts for the scenarios inc luding hourly

emission values and seasonally

- based hourly background concentrations. These results
were calculated with the actual stack height and downwash option in AERMOD.

Ta ble 4

- 1 Modeled 3

- year Average Impacts

Pollutant Averaging
period 4 th highest

concentration
, Somerset

contribution 4 th highest

concentration
, including
background SO 2 NAAQS

SO 2 1 hour 35.0 ppb ( 91.9 μg/m 3 ) 42.6 ppb ( 111. 7 μg/m 3 ) 75 ppb (196 μg/m 3 )

F i gure 4-1 shows the nearby imp acts of the facility (not including background) on

the 1

- hour SO 2 design value over the 2011

- 2013 period in μg/m3

. The highest impact s occur just northeast and southeast of the facility’s property.Figure 4

- 1 Modeled Impact of Somerset Station 1

- hour SO 2 over 2011

- 2013.

A ERMOD was also applied with single emission value ( based on the MATS emission

limit ), GEP stack height and 5 years of meteorological data to determine the future
potential maximum impacts from the Somerset Station. The resulting maximum model

predicted 1

- hour SO 2 imp act of Somerset Unit 1 was 34.2 μg/m 3 (13.0 ppb). Even with the ambient background concentration added to the Unit 1 impacts, the total

concentrations are well under 50% of the NAAQS.5.0 CONCLUSIONS

Th e m od e ling performed demonstrates that S om er se t Ge nera ting Sta tion does not

c au se or c ontribut e to a viol a tion of th e 1- hour SO 2 NAAQS. Therefore, an a tt a inm e nt

d es ign a tion for the area around the sta tion is r ecomm e nd ed.6.0 REFERENCES

N ew York State Department of Environmental Conservation : DAR

- 10 / NYSDEC Guidelines on Dispersion Modeling Procedures for Air Quality Impact Analysis, May, 2006

U .S. Environmental Protection Agency: (USEPA 2011) USEPA memo entitled “Additional Clarification Regarding Application of Appendix W Modeling Guidance for the 1

- hour NO2 National Ambient Air Quality Standard”, USEPA, Office of A ir Quality Planning and Standards, Raleigh, NC. 1 March 2011.

U .S. Environmental Protection Agency: (USEPA 2009) AERMOD Implementation Guide, AERMOD Implementation Workgroup. 19 March 2009.

U .S. Environmental Protection Agency : (U S EPA 2005) Guideline on Air Quality Models (GAQM, 40CFR Appendix W), November, 2005