, 

March 19, 2012 

Mr. Gerardo Rios 

Chief, Permits Office 

U.S. EPA Region 9 

75 Hawthorne Street 

San Francisco, CA 94105 

Subject: Pio Pico Energy Center PSD Permit Application 

 Response to EPA Supplemental Information Request 

 

Dear Mr. Rios: 

As requested by EPA on March 8, 20121

 , we are submitting this additional information 

on behalf of Applicant. 

Applicant submitted the PSD permit application on April 1, 2011. The original PSD 

permit application included a visibility screening analysis. 

Following guidance from Federal Land Managers (FLMs)2 on assessing visibility 

impacts, the PSD application included the determination that the project would have no 

significant adverse impact on Class I areas.3 

In the PSD permit application, Applicant also prepared a visibility analysis for the two 

Class II areas within 50 km of the project. This analysis was prepared following EPA 

procedures for evaluating the potential for visibility impairment on Class I areas.4 This 

procedure involves a series of screening analyses of increasing complexity. Based on 

EPA guidance5

, if the results of the Level 1 screening analysis are below the screening 

threshold, no further analysis is required. 

The Class I threshold is the level at which the FLM is likely not to object to the issuance 

of the PSD permit based on near field visibility impacts to a Class I area6. EPA has not 

yet established quantitative visibility thresholds for Class II areas. Consequently, in the 

PSD permit application, Applicant proposed to use a Class II threshold that was 

 

1

 Email from Cleveland Holladay to Steve Hill, March 8, 2012. 

2

 U.S. Forest Service et al., “Federal Land Managers’ Air Quality Related Values Work Group (FLAG), 

Phase I Report—Revised (2010),” October 2010, p. 18 

3

 Resubmitted PSD Application, p. PSD-4.57 

4 U.S. EPA, Workbook for Plume Visual Impact Screening and Analysis (Revised), EPA-454/R-92-023, October 1992 5 U.S. EPA, Workbook for Plume Visual Impact Screening and Analysis (Revised), EPA-454/R-92-023, October 1992, 

p. 1

6 U.S. EPA, Workbook for Plume Visual Impact Screening and Analysis (Revised), EPA-454/R-92-023, October 1992, 

p. 1

sierra 

research

1801 J Street 

Sacramento, CA 95811 

Tel: (916) 444-6666 

Fax: (916) 444-8373

Ann Arbor, MI 

Tel: (734) 761-6666 

Fax: (734) 761-6755 
Gerardo Rios -2- March 19, 2012 

extrapolated from the Class I thresholds using the ratio of Class II PM10 increment to 

Class I PM10 increment. A threshold less-stringent than the Class I area threshold for 

triggering the much more complex Level 2 analysis was proposed for the Class II area 

analysis because (a) there is a distinction between the degrees of protection applicable to 

Class I and Class II areas; (b) Class I areas can be protected through AQRV analysis, 

whereas protection of Class II areas can be achieved using BACT requirements; and (c) 

the results of the Class II visibility analysis are for informational, not regulatory, 

purposes. 

As shown in the PSD application, the results of the Level 1 screening analysis exceeded 

the Class I threshold, but were below the proposed Class II threshold. On March 8, 

2012, more than 11 months after the original analysis was submitted to EPA, Region 9 

staff has requested a Level 2 screening analysis for Class II areas, despite the fact that 

EPA has not yet established significance thresholds for such an analysis. 

The results of the requested Level 2 screening analysis are presented for Cleveland 

National Forest and Cabrillo National Monument in Tables 1 and 2 below, respectively. 

Tables 1 and 2 show that the maximum visual impacts inside these two Class II areas are 

below the Class I significance criteria. Visual impacts outside the Class II areas are 

“integral vistas” that are not protected.7 Consequently, per EPA guidance, 8 the 

VISCREEN results for plume parcels outside the Class II area are ignored. Because the 

visual impacts inside the Class II areas are below the significance criteria, this completes 

the visibility analysis.9

 

 

7

 National Park Service, Visibility Protection http://www.nature.nps.gov/air/regs/visibility.cfm

(accessed 3/14/2012) 

8 U.S. EPA, Workbook for Plume Visual Impact Screening and Analysis (Revised), EPA-454/R-92-023, October 1992, 

p. 27

9 U.S. EPA, Workbook for Plume Visual Impact Screening and Analysis (Revised), EPA-454/R-92-023, October 1992, 

p. 1
Gerardo Rios -3- March 19, 2012 

TABLE 1 

PPEC IMPACTS ON VISIBILITY IN CLEVELAND NATIONAL FOREST 

(LEVEL 2 SCREENING ANALYSIS) 

 Background Ozone:0.04 ppm Emission Density Diameter 

 Background Visual Range: 95 kmb Particulate: 2.08 g/s 2.5 1 

 Source-Observer Distance: 23 km NOx: 4.54 g/s 

 Min. Source-Class II Distance: 23 km Primary NO2 0.00 g/s 

 Max. Source-Class II Distance: 50 km Soot 0.00 g/s 2.0 1 

 Plume-source-observer angle: 11.25 degrees Sulfate 0.00 g/s 1.5 4 

 Stability: 6 

 Wind Speed: 2.00 m/s 

Maximum Visual Impacts INSIDE Class II Area a 

 Delta E Contrast 

Background Theta Azi Dist Alpha 

Class I 

Criterion Plume 

Class I 

Criterion Plume 

Sky 10 145 32.8 24 2.0 0.642 0.05 -0.005 

Sky 140 145 32.8 24 2.0 0.458 0.05 -0.003 

Terrain 10 159 50 9 2.0 0.703 0.05 0.008 

Terrain 140 159 50 9 2.0 0.314 0.05 0.009 

Maximum Visual Impacts OUTSIDE Class II Area a,c 

 Delta E Contrast 

Background Theta Azi Dist Alpha 

Class I 

Criterion Plume 

Class I 

Criterion Plume 

Sky 10 1 1 168 N/A 1.581 N/A -0.025 

Sky 140 1 1 168 N/A 1.346 N/A -0.011 

Terrain 10 1 1 168 N/A 3.247 N/A 0.038 

Terrain 140 1 1 168 N/A 1.449 N/A 0.043 

a Impacts based on 4 startups and 4 shutdowns of each turbine in a single day, remainder of day at peak operation. b National Park Service, Visibility Monitoring Data, http://www.nature.nps.gov/air/monitoring/vismon.cfm#data (accessed 3/17/2011) c VISCREEN results for plume parcels outside the Class II area are ignored. 
Gerardo Rios -4- March 19, 2012 

TABLE 2 

PPEC IMPACTS ON VISIBILITY IN CABRILLO NATIONAL MONUMENT 

(LEVEL 2 SCREENING ANALYSIS) 

 Background Ozone: 0.04 ppm Emission Density Diameter 

 Background Visual Range: 95 kmb Particulate: 2.08 g/s 2.5 1 

 Source-Observer Distance: 32 km NOx: 4.54 g/s 

 Min. Source-Class II Distance: 32 km Primary NO2 0.00 g/s 

 Max. Source-Class II Distance: 33 km Soot 0.00 g/s 2.0 1 

 Plume-source-observer angle: 11.25 degrees Sulfate 0.00 g/s 1.5 4 

 Stability: 6 

 Wind Speed: 2.00 m/s 

Maximum Visual Impacts INSIDE Class II Area a 

Delta E Contrast 

Background Theta Azi Dist Alpha 

Class I 

Criterion Plume 

Class I 

Criterion Plume 

Sky 10 93 33 75 2.0 0.379 0.05 -0.003 

Sky 140 93 33 75 2.0 0.264 0.05 -0.002 

Terrain 10 84 32 84 2.0 0.303 0.05 0.002 

Terrain 140 84 32 84 2.0 0.117 0.05 0.003 

Maximum Visual Impacts OUTSIDE Class II Area a,c 

Delta E Contrast 

Background Theta Azi Dist Alpha 

Class I 

Criterion Plume 

Class I 

Criterion Plume 

Sky 10 0 1 168 N/A 1.027 N/A -0.018 

Sky 140 0 1 168 N/A 0.729 N/A -0.008 

Terrain 10 0 1 168 N/A 2.030 N/A 0.028 

Terrain 140 0 1 168 N/A 0.884 N/A 0.031 

a Impacts based on 4 startups and 4 shutdowns of each turbine in a single day, remainder of day at peak operation. b National Park Service, Visibility Monitoring Data, http://www.nature.nps.gov/air/monitoring/vismon.cfm#data (accessed 3/17/2011) c VISCREEN results for plume parcels outside the Class II area are ignored.

As requested by EPA, the above analysis is submitted only for informational purposes. 

Please do not hesitate to call me if you have any questions. 

Sincerely, 

Steve Hill 

cc: John McKinsey, Stoel Rives LLP 

David Jenkins, Apex Power Group 

 Steve Moore, SDAPCD