# Plant Scherer AERMET Surface Characteristics Comparison

November 24 , 2015

S ince no on

- site met eorological data was available, t he surface and upper air observations from

the Middle Georgia Regional Airport located in Macon, GA (surface) and the Peachtree City,

GA (upper) NWS s tations for the period of 2012

- 2 014 were used in this modeling.

AERMOD modeling for Georgia Power’s Plant Scherer facility was performed with two sets of

surface characteristics ( a lbedo, Bowen r atio, and s urface r oughness) . One set of surface

characteristics was based on the Macon Middle Georgia Regional Airport NWS sur face

meteorological station (Macon NWS station) while the other set was based on the surface

characteristics surrounding the Plant Scherer facility site . Both sets used AERSURFACE ( 13016)

derived for twelve 30

- degree sectors out to 1 km at a seasonal temporal resolution for average

surface moisture conditions. A comparison of the surface characteristics between the Macon

NWS station and the facility site is shown in Table 1. N o significant differences in the a lbedo

and Bowen ratio were found. However, significant differences in the surface roughness were

observed

.

Figure 1 contains the 4 th 

## highest modeled maximum 1

- hou r SO 2 

## concentration averaged over

3

- years using the surface characteristics at the Macon NWS station . The maximum value was

located at approximately 4.4 kilometers south west of Plant Scherer . Figure 2 contains the 4 th



## h ighest modeled maximum 1

- hour SO 2 

## concen tration averaged over 3

- years using the sur face

characteristics at facility site. The maximum value was located at approximately 3.5 kil ometers

west of Plant Scherer

. Figure 3 shows a three year wind rose at the Macon NWS station for

2012

- 2014.

Table 2 contains the AERMOD m od eling results (  g/m 3 

## ) using the surface characteristics at the

Macon NWS station and the surface characteristics at the Plant Scherer facility site. Table 3

contains the AERMOD m od eling results ( ppb ) using the surface characteristics at the Macon

NWS station and the surface characteristics at the Plant Scherer facility site. The result s from

both model runs indicate that SO 2 

## emissions from Plant Scherer do not cause or contribute to any

violations of the 1

- hour SO 2 

## NAAQS

.

## Table1. C omparisons of a lbedo, Bowen r atio, and s urface r oughness at the Macon NWS station

and the Plant Scherer facility site

.

Macon NWS S tation Plant Scherer Facility Site

Albedo Bowen

Ratio Surface

Roughness Albedo Bowen

Ratio Surface

Roughness  Surface

Roughness  % Surface

Roughness Time

Frequency Wind

Sector

0.16 0.58 0.018 0.15 0.64 0.204

- 0.19

- 91.2 Winter 1 of 12

0.16 0.58 0.016 0.15 0.64 0.107

- 0.09

- 85.0 Winter 2 of 12

0.16 0.58 0.026 0.15 0.64 0.027 0.00

- 3.7 Winter 3 of 12

0.16 0.58 0.030 0.15 0.64 0.040

- 0.01

- 25.0 Winter 4 of 12

0.16 0.58 0.041 0.15 0.64 0.187

- 0.15

- 78.1 Winter 5 of 12

0.16 0.58 0.036 0.15 0.64 0.028 0.01 28.6 Winter 6 of 12

0.16 0.58 0.024 0.15 0.64 0.029

- 0.01

- 17.2 Winter 7 of 12

0.16 0.58 0.039 0.15 0.64 0.109

- 0.07

- 64.2 Winter 8 of 12

0.16 0.58 0.016 0.15 0.64 0.167

- 0.15

- 90.4 Winter 9 of 12

0.16 0.58 0.036 0.15 0.64 0.223

- 0.19

- 83.9 Winter 10 of 12

0.16 0.58 0.062 0.15 0.64 0.143

- 0.08

- 56.6 Winter 11 of 12

0.16 0.58 0.042 0.15 0.64 0.179

- 0.14

- 76.5 Winter 12 of 12

0.15 0.39 0.025 0.14 0.50 0.238

- 0.21

- 89.5 Spring 1 of 12

0.15 0.39 0.023 0.14 0.50 0.127

- 0.10

- 81.9 Spring 2 of 12

0.15 0.39 0.036 0.14 0.50 0.032 0.00 12.5 Spring 3 of 12

0.15 0.39 0.042 0.14 0.50 0.047

- 0.01

- 10.6 Spring 4 of 12

0.15 0.39 0.055 0.14 0.50 0.254

- 0.20

- 78.3 Spring 5 of 12

0.15 0.39 0.045 0.14 0.50 0.031 0.01 45.2 Spring 6 of 12

0.15 0.39 0.030 0.14 0.50 0.032 0.00

- 6.3 Spring 7 of 12

0.15 0.39 0.050 0.14 0.50 0.135

- 0.09

- 63.0 Spring 8 of 12

0.15 0.39 0.023 0.14 0.50 0.208

- 0.19

- 88.9 Spring 9 of 12

0.15 0.39 0.050 0.14 0.50 0.263

- 0.21

- 81.0 Spring 10 of 12

0.15 0.39 0.085 0.14 0.50 0.178

- 0.09

- 52.2 Spring 11 of 12

0.15 0.39 0.057 0.14 0.50 0.207

- 0.15

- 72.5 Spring 12 of 12

0.17 0.40 0.034 0.14 0.27 0.350

- 0.32

- 90.3 Summer 1 of 12

0.17 0.40 0.039 0.14 0.27 0.162

- 0.12

- 75.9 Summer 2 of 12

0.17 0.40 0.104 0.14 0.27 0.039 0.07 166.7 Summer 3 of 12

0.17 0.40 0.187 0.14 0.27 0.060 0.13 211.7 Summer 4 of 12

0.17 0.40 0.182 0.14 0.27 0.420

- 0.24

- 56.7 Summer 5 of 12

0.17 0.40 0.098 0.14 0.27 0.039 0.06 151.3 Summer 6 of 12

0.17 0.40 0.063 0.14 0.27 0.039 0.02 61.5 Summer 7 of 12

0.17 0.40 0.087 0.14 0.27 0.185

- 0.10

- 53.0 Summer 8 of 12

0.17 0.40 0.055 0.14 0.27 0.250

- 0.20

- 78.0 Summer 9 of 12

0.17 0.40 0.108 0.14 0.27 0.315

- 0.21

- 65.7 Summer 10 of 12

0.17 0.40 0.117 0.14 0.27 0.253

- 0.14

- 53.8 Summer 11 of 12

0.17 0.40 0.082 0.14 0.27 0.287

- 0.21

- 71.4 Summer 12 of 12

0.17 0.58 0.029 0.14 0.64 0.350

- 0.32

- 91.7 Fall 1 of 12

0.17 0.58 0.032 0.14 0.64 0.162

- 0.13

- 80.2 Fall 2 of 12

0.17 0.58 0.095 0.14 0.64 0.039 0.06 143.6 Fall 3 of 12

0.17 0.58 0.186 0.14 0.64 0.060 0.13 210.0 Fall 4 of 12

0.17 0.58 0.180 0.14 0.64 0.420

- 0.24

- 57.1 Fall 5 of 12

0.17 0.58 0.097 0.14 0.64 0.039 0.06 148.7 Fall 6 of 12

0.17 0.58 0.062 0.14 0.64 0.039 0.02 59.0 Fall 7 of 12

0.17 0.58 0.083 0.14 0.64 0.185

- 0.10

- 55.1 Fall 8 of 12

0.17 0.58 0.047 0.14 0.64 0.250

- 0.20

- 81.2 Fall 9 of 12

0.17 0.58 0.097 0.14 0.64 0.315

- 0.22

- 69.2 Fall 10 of 12

0.17 0.58 0.104 0.14 0.64 0.253

- 0.15

- 58.9 Fall 11 of 12

0.17 0.58 0.072 0.14 0.64 0.287

- 0.22

- 74.9 Fall 12 of 12

## Figure 1. Plot of the 4 th 

## h ighest maximum d aily 1-hour SO 2 

## (ppb) averaged over 3 years using

surface roughness at the Macon NWS station.

Figure 2. Plot of the 4 th 

## h ighest maximum d aily 1-hour SO 2 

## (ppb) averaged over 3 years using

surface roughness at the Plant Scherer facility site.

## Fig ure 3

. Three year w ind rose at the Macon NWS station for 2012

- 2014.

Table 2

. Summary of 1

- hour SO 2 

## NAAQS (  g/m 3 

## ) a nalysis using the surface roughness at the

Macon NWS station and the Plant Scherer facility site

.

Surface

Roughness

Location SO 2



### Averaged

Period SO 2 

### Model Design

Concentration

(  g/m 3 

### ) SO 2 

### Background

Concentration

(  g/m 3 

### ) SO 2 

### Total

Concentration

(  g/m 3 

### ) SO 2



### NAAQS

(  g/m 3 

### ) Below SO 2



### NAAQS

(Y/N)

Macon NWS

S tation 1

- hour 98.24 30.3 128.54 196 Y

F acility S ite 1

- hour 94.66 30.3 124.97 196 Y



## Table 3

. Summary of 1

- hour SO 2 

## NAAQS (ppb ) a nalysis using the surface roughness at the

Macon NWS station and the Plant Scherer facility site.

Surface

Roughness

Location SO 2



### Averaged

Period SO 2 

### Model Design

Concentration

( pp b ) SO 2 

### Background

Concentration

(pp b ) SO 2 

### Total

Concentration

( pp b ) SO 2



### NAAQS

(pp b ) Below SO 2



### NAAQS

(Y/N)

Macon NWS

Station 1

- hour 37.5 11.6 49.1 75 Y

Facility Site 1

- hour 36.1 11.6 47.7 75 Y