# Exhibit 7

## Kanawha River **Plant**

**Glasgow, West Virginia**

**Sierra Club Evaluation of Compliance with 1**

**- hour SO**  **2** 

## NAAQS

**October 25 , 201**  **1**

Conducted by:

Steven Klafka, P.E., BCEE

Wingra Engineering, S.C.

Madison, WisconsinSierra Club Evaluation of Compliance with 1

- hour SO2 NAAQS October 25 , 2011 Page 1

**1. Introduction** 

The Sierra Club prepared an air modeling impact analysis to help USEPA, state and local air agencies identify facilities that are likely causing violations of the one

- hour sulfur dioxide (SO 2 ) national ambient air quality standard (NAAQS). This document descr ibes the results and procedures
for an evaluation conducted for the Kanawha River Plant located in Glasgow, West Virginia

.

The dispersion modeling analysis predicted ambient air concentrations for comparison w ith the one

h our SO 2 NAAQS. The modeling was performed using data provided to the Sierra Club by regulatory air agencies and through other common sources described below.

**2. Compliance with the**  **One**

**- Hour SO**  **2 NAAQS** 

**2.1 One** 

**- Hour SO**  **2 NAAQS** 

The one

- hour SO 2 NAAQS takes the form of a th ree

- year average of the 99 th

- percentile of the annual distribution of daily maximum one

- hour concentrations, which cannot exceed 75 ppb. 1 Compliance
with this standard wa s verified using USEPA’s AERMOD air dispersion model, which produces air
concentratio ns in units of μg/m 3 . The one

- hour SO 2 N AAQS of 75 ppb equals 196.2 μg/m 3 , and this is the value used for determining whether modeled impacts exceed the NAAQS. 2 The 99 th

percentile of the annual distribution of daily maximum one

- hour concentrations corresponds to the
fourth

- highest value at each receptor for a given year.

**2.2 Modeling Results** 

Modeling results for Kanawha River Plant are summarized in Table 1. It was determined that based on either currently permitted emissions or measured actual em issions , the Kanawha River Plant is
estimated to create downwind SO 2 concentrations which exceed the 1

- hour NAAQS.

The currently approved and measured actual emission rates used for the modeling analysis are summarized in Table 2. Based on the modeling r esults, emission reductions from current rates considered necessary to achieve compliance with the 1

- hour NAAQS were calculated and presented
in Table 3.

1 USEPA, Applicability of Appendix W Modeling Guidance for the 1

- hour SO 2 National Ambient Air Quality Standard, August 23, 2010.

2 The ppb to μg/m 3 conversion is found in the source code to AERMOD v. 11103, subroutine Modules. The conversion calculation is 75/0.3823 = 196.2 μg/m 3

.Sierra Club Evaluation of Compliance with 1

- hour SO2 NAAQS October 25 , 2011 Page 2

Predicted exceedences of the 1

- hour NAAQS for SO 2 extend throughout West Virginia to a
maximum dist ance of 50 kilometers.

Figure 1 provided as an appendix to this report shows the extent of NAAQS violations throughout the entire 50 kilometer modeling domain.

Figure 2 provides a c lose

- up local view of NAAQS violations

.

Air quality impacts in West Virginia are based on a background concentration of 91.6 μg/m 3

. This is
the 2008

- 10 design value for Cabell County, West Virginia . This is the lowest measured background concentration in the state and so may under

- predict compliance with the NAAQS.

**2.3 Co**  **nservative Modeling Assumptions**

A dispersion modeling analysis requires the selection of numerous parameters which affect the predicted concentrations. For the enclosed analysis, several parameters were selected which under

predict facility impacts.

Ass umptions used in this modeling analysis which likely under

- estimate concentrations include the following:

x A llowable emissions based on a 24

- hour average were used t o determine compliance with the 1

- hour average NAAQS. Emissions during any 1

- hour period ma y be higher than assumed for the modeling analysis.

x No consideration of facility operation at less than 100% load. Stack parameters such as exit flow rate and temperature are typically lower at less than full load, reducing pollutant dispersion and increas ing predicted air quality impacts.

x No consideration of building or structure downwash. These downwash effects typically increase predicted concentrations near the facility.

x No consideration of off

- site sources. These other sources of SO 2 will increase the predicted impacts.Sierra Club Evaluation of Compliance with 1

- hour SO2 NAAQS October 25 , 2011 Page 3

Table 1

- SO 2 Modeling Results for Kanawha River Plant Modeling Analysis

Location Emission
Rates Averaging Period 99 th Percentile 1

- hour Daily Maximum ( μg/m 3 ) Complies with NAAQS? Impact Background Total NAAQS

West Virginia Allowable 1

- hour 10

, 782.4 91.6 10,874.0 196.2 No

Maximum 1

- hour 9,1 24.1 91.6 9,2 15.7 196.2 No

Table 2

- Modeled SO 2 Emissions from Kanawha River Plant

Stack

ID Unit
ID Allowable Emissions 3

24

- hour Average (lbs/hr) Maximum Emissions 4

1

- hour Average (lbs/hr)

S01 Unit 1 2,668.7
Unit 2 2,656.6
Stack Total All Units 6,240.0 5,325.3

Table 3

- Required Emission Reductions for Compliance with 1

- hour SO 2 NAAQS

Location Acceptable Impact (NAAQS

- Background) 99th Percentile
1

- hour Daily Max ( μg/m 3 ) Required Total Facility Maximum Emission Reduction (%) Required Total Facility Maximum Emission
Rate (lbs/hr)
West Virginia 104.6 99.0 60.5

3 Allowable emissi ons are limitation s in P ermit No: R30

- 03900006

- 2009 issued May 28, 2009 by WVDEP

. 4 Maximum emission s are measured hourly rates reported for 2010 in USEPA, Clean A ir Markets

- Data and Maps.Sierra Club Evaluation of Compliance with 1

- hour SO2 NAAQS October 25 , 2011 Page 4

**3. Modeling Methodology** 

**3.1 Air**  **Dispersion Model**

The modeling analysis used USEPA’s AERMOD program, version 11103. AERMOD, as available from the Support Center for Regulatory Atmospheric Modeling (SCRAM) website, was used in conjunction with a third

- party modeling software program, AERMOD View , sold by Lakes
Environmental Software.

**3.2 Control Options** 

The AERMOD model was run with the following control options:

x One

- hour average air concentrations

x Regulatory defaults

x Flagpole receptors

To reflect a representative inhalation level, a flagpole height of 1.5 meters was used for all modeled receptors. This parameter was added to the receptor file when runnin g AERMAP, as described in
Section 4.4.

An evaluation was conducted to determine if the modeled facility was located in a rural or urban setting using USEPA’s methodology outlined in Section 7.2.3 of the Guideline on Air Quality
Models. 5 For urban sources , the URBANOPT option is used in conjunction with the urban population from an appropriate nearby city and a default surface roughness of 1.0 meter. Methods described in Section 4.1 to determine whether rural or urban dispersion coefficients were used.

**3.3 Output Options** 

The AERMOD analysis was based on five years of recent meteorological data. The surface
measurements were obtained from the Charleston Yeager Airport located 14 miles north west of the
Kanawha River Plant and were supplemented with upper air measurements from the station at Blacksburg/Roanoke, Virginia. The modeling analyses used one run with five years of sequential meteorological data from 2006

- 2010. Consistent with USEPA’s Modeling Guidance for SO 2 NAAQS Designations, the MXDYBYYR and MAXD CONT output options were used to create a
table of fourth

- high one

- hour SO 2 impacts. 6 This provided a file of one

- hour SO 2 concentrations

5 USEPA, Revision to the Guideline on Air Quality Models: Adoption of a Preferred General Purpose (Flat and Complex Terrain) Dispersion Model and Other Revisions, Appendix W to 40 CFR Part 51, November 9, 2005.

6 USEPA, Area Designations for the 2010 Revised Primar y Sulfur Dioxide National Ambient Air Quality Standards, Attachment 3, March 24, 2011, p p. 24

- 26

.Sierra Club Evaluation of Compliance with 1

- hour SO2 NAAQS October 25 , 2011 Page 5

consistent with the form of the one

- hour SO 2 NAAQS. It is from these files that the maximum one

hour SO 2 value was determined and reported.

Please refer to Table 1 for the modeling results. Please see the supporting f igures for a presentation of concentration isopleths.

**4. Model Inputs** 

**4.1 Geographical**  **Inputs**

The “ground floor” of all air dispersion modeling analyses is establishing a coordinate system for identifying the geographical location of emission sources and receptors. These geographical locations are used to determine local characteristics (such as land use and elevation), and also to

ascer tain source to receptor distances and relationships.

The Universal Transverse Mercator (UTM) NAD83 coordinate system was used for identifying the easting (x) and northing (y) coordinates of the modeled sources and receptors. Stack locations were
obtained from facility permits and prior modeling files provided by the West Virginia Department of
Environmental Protection . The stack locations were then verified using aerial photographs.

The facility was evaluated to determine if it should be modeled using th e rural or urban dispersion coefficient option in AERMOD. A GIS was used to determine whether rural or urban dispersion coefficients apply to a site. Land use within a three

- kilometer radius circle surrounding the facility was considered. USEPA guidance states that urban dispersion coefficients are used i f more than 50%
of the area within 3 kilometers has urban land uses. Otherwise, rural dispersion coefficients are appropriate. 7

USEPA’s AERSURACE model Version 08009 was used to develop the meteorologi cal data for the modeling analysis. This model was also used to evaluate surrounding land use within 3 kilometers. Based on the output from the AERSURFACE, approximately 1 9 % of surrounding land use around
the airport was of urban land use types including: 21

– Low Intensity Residential, 22

– High Intensity Residential, and 23

- Commercial/Industrial/Transportation.

This is less than the 50% value considered appropriate for the use of urban dispersion coefficients. Based on the AERSURFACE analysis, it was concluded that the rural option would be used for the modeling summarized in this report. Please refer to Section 4.5.3 for a discussion of the AERSURFACE analysis.

7 USEPA, Revision to the Guideline on Air Quality Models: Adoption of a Preferred General Purpose (Flat and Complex Terrain) Dispersion Model and Other Revisi ons, Appendix W to 40 CFR Part 51, November 9, 2005 , Section 7.2.3.Sierra Club Evaluation of Compliance with 1

- hour SO2 NAAQS October 25 , 2011 Page 6

**4.2 Emission**  **Rate s and Source Parameters** 

The mo deling analyses only considered SO 2 emissions from the facility. Off

- site sources were not considered. Concentrations were predicted for two scenarios shown in Table 2:

1) approved or allowable emissions based on permits issued by the regulatory agency, and

2) measured actual hourly SO 2 emissions obtained from USEPA’s Clean Air Markets
Database. To assure realistic emission rates were used, emissions from both units were combined and the hour with the maximum total facility emissions was used to determi ne the
actual emissions.

Stack parameters and emissions used for the modeling analysis are summarized in Table 4. Stack
S01 exhausts both units at the facility. The emissions are the total for both units.

Table 4

– Kanawha River Plant Stack Parameters and Emissions

Description S01 (WVDEP ID # CS012 ) X Coord. [m] 462971 Y Coord. [m] 4228837 Base Elevation [m] 189.51 Release Height [m] 99.36 Gas Exit Temperature [ ° K] 430.928

Gas Exit Velocity [m/s] 14.344

Inside Diameter [m] 5.995
Allowable Emission Rate [g/s] 786.2
Maximum Emission Rate [g/s] 671

The above stack parameters and emissions were obtained from regulatory agency permit files. 8 9 The analysis was conducted based on 100% operating load using maximum exhaust flow rates and emission rates. Operation at less than full capacity loads was not considered. This assumption tends
to under

- predict impacts since s tack parameters such as exit flow rate and temperature are typically lower at less than full load, reducing pollutant dispersion and increasing predicted air quality impacts. Stack location, height and diameter were verified using aerial photographs, and flue gas flow rate and tempera ture were verified using combustion calculations.

8 WVDEP

, Permit No. R30

- 03900006

- 2009

, May 28, 2009.

9 WVDEP, Stack parameters provided in the file ‘e mit.txt. ’Sierra Club Evaluation of Compliance with 1

- hour SO2 NAAQS October 25 , 2011 Page 7

**4.3 Building Dimensions and GEP** 

No building dimensions or prior downwash evaluations were available. Therefore this modeling analysis did not address the effects of downwash which may increase predicted concentrations.

**4.4 Receptors** 

For Kanawha River Plant , three receptors grids were employed:

1. A 100

- meter Cartesian receptor grid centered on Kanawha River Plant and extending out 5
kilometers.

2. A 500

- meter Cartesian receptor grid centered on Kanawha River Plant and extending out 10
kilometers.
3. A 1

, 0 00

- meter Cartesian receptor grid centered on Kanawha River Plant and extending out
5 0 kilometers. 50 kilometers is the maximum distance accepted by USEPA for the use of the AERMOD dispersion model. 10

A fla gpole height of 1.5 meters was used for all these receptors.

Elevations from stacks and receptors were obtained from National Elevation Dataset (NED) GeoTiff
data. GeoTiff is a binary file that includes data descriptors and geo

- referencing information

nece ssary for extracting terrain elevations. These elevations were extracted from 1 arc

- second ( 3 0 meter) resolution NED files using USEPA’s AERMAP program, v. 11103

.

**4.5 Meteorological Data** 

To improve the accuracy of the modeling analysis, recent meteorological data for the 2006 to 2010 period were prepared using the USEPA’s program AERMET which creates the model

- ready surface and profile data files required by AERMOD. Required data inputs to AERMET included surface meteorological measurements, twice

- daily soundings of upper air measurements, and the micrometeorological parameters surface roughness, albedo, and Bowen ratio. One

- minute ASOS
data were available so USEPA methods were used to r educe calm and missing hours. 11

This section discusses how the meteorological data was prepared for use in the one

- hour SO 2 NAAQS modeling analyses. AERMET v. 11059 was used for these tasks.

10 USEPA, Revision to the Guideline on Air Quality Models: Adoption of a Preferred General Purpose (Flat and Complex Terrain) Dispersion Model and Other Revisions, Appendix W to 40 CFR Part 51, Section A.1.(1), November 9, 2005.
11 USEPA, Area Designations for the 2010 Revised Primary Sulfur Dioxide National Ambient Air Quality Standards, Attachment 3, March 24, 2011, p . 19.Sierra Club Evaluation of Compliance with 1

- hour SO2 NAAQS October 25 , 2011 Page 8

**4.5.1 Surface**  **Meteorology**

Surface meteorology was obtained for Charleston Yeager Airport located 14 miles north west of the
Kanawha River Plant . Integrated Surface Hourly (ISH) data for the 2006 to 2010 period were obtained from the National Climatic Data Center (NCDC). The ISH su rface data was processed through AERMET Stage 1, which performs data extraction and quality control checks.

**4.5.2 Upper Air Data** 

Upper

- air data are collected by a “weather balloon” that is released twice per day at selected
locations. As the balloon i s released, it rises through the atmosphere, and radios the data back to the surface. The measuring and transmitting device is known as either a radiosonde, or rawindsonde. Data collected and radioed back include: air pressure, height, temperature, dew point, wind speed,
and wind direction. The upper air data were processed through AERMET Stage 1, which performs data extraction and quality control checks.

For Kanawha River Plant , the concurrent 2006 through 2010 upper air data from twice

- daily radiosonde measurements obtained at the most representative location were used. This location was
the Blacksburg/Roanoke, Virginia measurement station. These data are in Forecast Systems

L aboratory (FSL) format and were downloaded in ASCII text format from NOAA’s FSL website

. 12
All reporting levels were downloaded and processed with AERMET.

**4.5.3 AERSURFACE** 

AERSURFACE is a non

- guideline program that extracts surface roughness, albedo, and daytime
Bowen ratio for an area surrounding a given location. AERSURFACE uses land use and land cover (LULC) data in the U.S. Geological Survey’s 1992 National Land Cover D ataset to extract the necessary micrometeorological data. LULC data was used for processing meteorological data sets used as input to AERMOD.

AERSURFACE v. 08009 was used to develop surface roughness, albedo, and daytime Bowen ratio values in a region su rrounding the meteorological data collection site. AERSURFACE was used to develop surface roughness in a one kilometer radius surrounding the data collection site. Bowen ratio and albedo was developed for a 10 kilometer by 10 kilometer area centered on t he meteorological data collection site. These micrometeorological data were processed for seasonal periods using 30

- degree sectors. S easonal moisture conditions were considered average with no
months with continuous snow cover.

12 Available at: http://esrl.noaa.gov/raobs/Sierra Club Evaluation of Compliance with 1

- hour SO2 NAAQS October 25 , 2011 Page 9

**4.5.4 Data Review** 

Missin g meteorological data were not filled as the data file met USEPA’s 90% data completeness requirement. 13 The AERMOD output file shows there w ere 2.4 % missing data.

The representativeness of airport meteorological data is a potential concern in modeling industrial
source sites. 14 The surface characteristics of the airport data collection site and the modeled source location were compared. Since the Charleston Yeager Airport is located close to Kanawha River
Plant (i.e. 14 miles), this meteorological data set was considered appropriate for this modeling analysis.

**5. Background**  **SO 2**  **Concentrations**

Background concentrations were determined consistent with USEPA’s Modeling Guidance for SO 2 NAAQS Designations. 15 To preserve th e form of the one

- hour SO 2 standard

, based on the 99 th
percentile of the annual distribution of daily maximum one

- hour concentrations averaged across the number of years modeled , the background fourth

- highest daily maximum one

- hour SO 2 concentration was ad ded to the modeled fourth

- highest daily maximum one

- hour SO 2 concentration. 16

Background concentrations were based on the 2008

- 10 d esign value measured by the ambient
monitors located in West Virginia

. 17

Air quality impacts in West Viginia and the supporting figures are based on a background
concentration of 91.6 μg/m3. This is the 2008

- 10 design value for Cabell County, West Virginia

. This is the lowest measured background concentration in the state and so may under

- pr edict compliance with the NAAQS

.

**6**

**. Reporting** 

All files from the programs used for this mod eling analysis are available to regulatory agencies. These include analyses prepared with AERSURFACE, AERMET, AERMAP, and AERMOD.

13 USEPA, Meteorological Monitoring Guidance for Regulatory Modeling Applications, EPA

- 454/R

- 99

- 05, February 2000, Section 5.3.2, p p. 5

- 4 to 5

- 5.

14 USEPA

, AERMOD Implementation Guide , March 19, 2009, pp. 3

- 4. 15 USEPA, Area Designations for the 2010 Revised Pr imary Sulfur Dioxide National Ambient Air Quality Standards, Attachment 3, March 24, 2011, p p. 20

- 23.

16 USEPA, Applicability of Appendix W Modeling Guidance for the 1

- hour SO 2 National Ambient Air Quality Standard

, August 23, 2010 , p. 3.

17 http://www.epa.gov/airtrends/values.html