## U.S. ENVIRONMENTAL P ROTECTION AGENCY

REGION IX

STATEMENT OF BASIS A ND AMBIENT AIR QUALITY IMPACT REPORT

For a Clean Air Act Prevention of Significant Deterioration Permit



# Sierra P acific Industries

- Anderson

PSD P ermit Number S AC 1 2

- 0 1

September 2012

### This page left intentionally blank

### PROPOSED PREVENTION OF SIGNIFICANT DETERIORATION

PERMIT

SPI

- Anderson Statement of Basis and Ambient Air Quality Impact Report

(PSD P ermit S AC 1 2

- 0 1 )



## Table of Contents

Executive Summary

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

1. Purpose of this Document

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

2. Applicant

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

3. Project Location

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

4. Project Description

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

5. Emissions from the Proposed Project

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

6. Applicability of the Prevention of Significant Deterioration Regula tions

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

7. Best Available Control Technology

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

7.1. BACT for a New Boiler at a Lumber Facility

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

7.1.1. Oxides of Nitrogen

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

7.1.2. Carbon Monoxide

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

7.1.3. Par ticulate Matter

- PM, PM 10 , PM 2.5

................................ ................................ .... 19

7.2 BACT for Emergency Engine

................................ ................................ ....................... 22

7.3. BACT for Cooling Towers

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

8. A ir Quality Impacts

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

8.1 Introduction

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

8.1.1 Overview of PSD Air Impact Requirements

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

8.1.2 Identification of SPI

- Anderson Modeling Documentation

................................ ...... 27

8.2. Background Ambient Air Quality

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

8.3 Modeling Methodology for Class II areas

................................ ................................ ........ 29

8.3.1 Model selection

................................ ................................ ................................ ......... 29

8.3.2 Mete orology model inputs

................................ ................................ ........................ 29

8.3.3 Land characteristics model inputs

................................ ................................ ............. 29

8.3.4 Model receptors

................................ ................................ ................................ ........ 30

8.3.5 Stack parameter model inputs

................................ ................................ ................... 30

8.3.6 Good Engineering Practice (GEP) Analysis

................................ ............................ 31

8.4 National Ambient Air Quality Standards (NAAQS) and PSD Class II Increment Consumption Analysis

................................ ................................ ................................ ............ 31

8.4.1 Pollutants with significant emissions

................................ ................................ ........ 31

8.4.2 Preliminary analysis: Project

- only impacts (Normal Operations and Startup)

......... 32

8.4.3 Cumulative impact analysis

................................ ................................ ...................... 33

8.5 Class I Area Analysis

................................ ................................ ................................ ........ 38

8.5.1 Air Quality Related Values

................................ ................................ ....................... 38

8.5.2 Class I Increment Consumption Analysis

................................ ................................ . 39

9. Additional Impact Analysis

................................ ................................ ................................ .... 4 0

9.1 Soils and Vegetation

................................ ................................ ................................ ......... 409.2 Visibility Impairment

................................ ................................ ................................ ........ 43

9.3 Gr owth

................................ ................................ ................................ .............................. 44

10. Endangered Species

................................ ................................ ................................ ................ 45

11. Environmental Justice Screening Analysis

................................ ................................ ............. 45

12. Clean Air Act Title V (Operating Permit)

................................ ................................ .............. 46

13. Comment Period, Procedures for Public Hearing Requests, Final Decision, and EPA Contact

................................ ................................ ........... 46

14. Conclusion and Proposed Action

................................ ................................ ............................ 48 Appendix A

................................ ................................ ................................ ................................ ... 49

## Acronyms & Abbreviations

AAQIR Ambient Air Quality Impact Report

ACC Air Cooled Condenser

Act Clean Air Act [42 U.S.C. Section 7401 et seq.] Agency U.S. Environmental p rotection Agency AQRV Air Quality Related Value

BACT Best Available Control Technology

BDT Bone Dry Tons

BTU British th ermal units

CAA Clean Air Act [42 U.S.C. Section 7401 et seq.]

CBI Confidential Business Information

CEMS Continuous Emissions Monitoring System

CFR Code of Federal Regulations

CO Carbon Monoxide

EPA U.S. Environmental p rotection Agency

ESA Endangered Species Act

FLM Federal Land Manager

FWS U.S. Fish and Wildlife Service GAQM 40 CFR p art 51 , Appendix W

- Guideline on Air Quality Models

GEP Good engineering practice hp Horsepower

HRSG Heat Recovery Steam Generator

kW kilowatt

m meter

MMBTU Million Brit ish thermal units

MW Megawatts of electrical power NAAQS National Ambient Air Quality Standards

NLCD92 USGS 1992 National Land Cover

NO Nitrogen oxide or nitric oxide

NO 2 Nitrogen d ioxide

NO

x Oxides of Nitrogen (NO + NO 2 )

NP National p ark

NSPS New Source p erformance Standards, 40 CFR p art 60

NSR New Source Review

PM Total p articulate Matter

PM 2.5 Particulate Matter less than 2.5 micrometers (μm) in diameter

PM 10 Particulate Matter less than 10 micrometers (μm) in diameter ppb parts per billion

ppm parts per million

PSD Prevention of Significant Deterioration

PTE potential to emit

RBLC U

. S

. EPA RACT/BACT/LAER Information Clearinghouse SCAQMD Shasta County Air Quality Management DistrictSCFM Standard Cubic Feet per Minute

SIA Significant Impact Area

SIL Si gnificant Impact Level

SO 2 Sulfur Dioxide

SO

x Oxides of Sulfur

SPI Sierra p acific Industries

tpy tons per year
USGS United States Geological Survey

WA Wilderness Area1 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 

## Proposed Prevention of Significant Deterioration (PSD) P ermit

Statement of Basis and Ambient Air Quality Impact Report

SPI

- Anderson

Executive Summary

Sierra P acific Industries (SPI) has applied for an approval to construct a new cogeneration unit capable of generating approximately 31 megawatt s (MW) of electricity by combusting clean cellulosic biomass during normal operation and natural gas for startup and shutdown . The cogeneration unit will be constructed within the physical

boundaries of the current SPI

- Anderson Division facility location. The facility is located at 19758 Riverside Avenue in Anderson, California 96007 (Assessor’s p arcel No. 050

- 110

- 025). The proposed major Prevention of Significant Deteri oration ( PSD ) permit

modification is cons istent with the requirements of the PSD program for the following

reasons:

 The proposed permit requires the Best Available Control Technology (BACT) for

Oxides of Nitrogen ( NO

x )

, Carbon Monoxide ( CO ), Total P articulate Matter (PM), P articulate Matter under 10 micrometers ( μ m) in diameter (PM 10 ) and

P articulate Matter under 2.5 μ m in diameter ( PM 2.5 );

 The proposed emission limits will protect the National Ambient Air Quality Standards (NAAQS) for NO 2 , CO, PM 10 and PM 2.5 . There is no NAAQS set for

Total P articulate Matter (PM);

 The facility will not adversely impact soi ls and vegetation, or air quality, visibility, and deposition in Class I areas , which are parks or wilderness areas given special protection und er the Clean Air Act (CAA) ;

 After informal consultation with the U.S. Fish and Wildlife Service under S ection

7 of the Endangered Species Act, EPA has concluded that the proposed

modification will have no likely adverse e ffect on any F ederally

- listed endangered

or threatened species or designated critical habitat in the project’s impact area.2 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 

## 1. Purpose of this Document

This document serves as the Statement of Basis and Ambient Air Quality Impact Report

for the proposed PSD permit modification for the SPI

– Anderson facility

. This document describes the legal and factual basis for the proposed permit, including requirements

under the PSD regulations at Title 40 of the Code of Federal Regulations (CFR) §52.21. This document also serves as the fact sheet to meet the requirements of 40 CFR Part

124.7 and 124.8.



## 2

. Applicant

S ierra P acific Industries

P.O. Box 496028 Redding , CA 96049

- 6028



## 3. Project Location

The proposed location for the modification of the SP I

- Anderson facility will be within the physical footprint of the current facility location. The facility is located at 19758 Riverside Avenue in Anderson, California 96007 (Assessor’s p arcel No. 050

- 110

- 025). The site is approximately 0 .5 mile west of Int erstate 5 , and approximately 2 mile s north

of the city of Anderson

. The facility is bordered on the northeast by the Sacramento River, on the northwest by a private parcel, on the southwest by Union P acific Railroad tracks and State Route (SR) 273, and on the southeast by private parcels. The city of

Anderson is located within the jurisdiction of the Shasta County Air Quality Management District (SCAQMD).

The map on the following page shows the approx imate location of SPI

- Anderson

.3 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 

## 4. Project Description

SPI has applied for an approval to construct and operate a new cogeneration unit capable of gen erating 31 MW of gross electrical output from the combustion of clean cellulosic

biomass and natural gas

.

The original PSD p ermit for this lumber manufacturing facility was issued in 1994 by the Shasta County Air Quality Management District ( SCAQMD )

. The site currently contains

a wood

- fired boiler with associated air pollution control equi pment and conveyance systems that produces steam to dry lumber in existing kilns. On March 3, 2003 USEPA revoked and rescinded SCAQMD’s authority to issue and modify federal PSD permits for4 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 new and modified major sources of attainment pollutants in Shasta County . Therefore, EPA is modifying the PSD permit issued by SCAQMD to incorporate the proposed

modifications.

A new cogeneration unit equipped with a stoker boiler is being proposed in order to burn

additional clean cellulosic biomass fuel . F uel will be generated on site from the lumber operations and delivered from other fuel sources to produce roughly 250,000 pounds per

hour of steam. Th is steam be used to dry lumber in existing kilns for the lumber operation , as well as feed a turbine that will drive a generator to produce electricity for

use on site or for sale to the electrical grid. A closed

- loop two

- cell cooling tower will be used to dispose of waste heat from the steam turbine.

Currently, t he Anderson lumber operation produces approxim ately 160,000 bone dry tons ( BDT ) of wood waste per year . Approximately 60,000 BDT are consumed by the existing cogeneration unit , 20,000 BDT are trucked to other biomass power plants, and the roughly 80,000 BDT balance is t r ucked to other markets (e.g. wo od chips to pulp mills)

. The new proposed boiler will have the capacity to consume a maximum of 219,000 BDT per year. Roughly 80,000 BDT will be generated by the facility’s existing lumber operations at its current output, additional wood fuel will be tran sported by truck to the facility from SPI ’ s other lumber operations in California.

The following page contains a design draft and a simplified process flow diagram for the proposed boiler

.5 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Air P ollution Control

SPI

- Anderson will employ several air pollution control alternatives to reduce the emissions of some criteria pollutants from the proposed new boiler. Selective Non

catalytic Reduction (S N CR) will be used to reduce NO

x emissions

. A mmonia will be

introduced i nto the furnace at the appropriate temperature window in order to most effectively decrease NO

x emissions. T o reduce particulate matter (PM) emissions, SPI

will use an e lectrostatic precipitator (ESP) preceded by a multiclone.6 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Permitted Equipment

Table 4

- 1 lists the proposed new equipment that will be regulated by this PSD permit:

Table 4

- 1 : P roposed New Equipment List

Stoker Boiler with Vibrating Grate Biomass

- f ired with natural gas burners for start

- up and

shutdown Maximum annual average heat input of 468 MMBtu/hr

and steam generation rate of 250,000 lbs /hr Equipped with two natural gas burners, each with a maximum rated heat input of 62.5 MMBtu/hr

E quipped with SNCR system to reduce nitrogen oxides,

and multiclone with ESP to control PM emissions

Emergency Engine 256 hp at 1,800 rpm Used to run the emergency boiler recirculation pump

Natural

- gas fired

Cooling Tower Composed of two

- cells with an expected water load of 4.24 gallons per minute per square foot.7 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 4

- 2 lists the existing equipment that is not included in this PSD permit. The equipment listed below is permitted by SCAQMD , and T a bl e 4

- 2 is provided for reference purposes only

.

Table 4

- 2 : Existing Equipment List

Wellons Stoker Boiler Biomass

- f ired with natural gas burners for start

- up Maximum annual average heat input of approximately

116.4 MMBtu/hr Equipped with SNCR system to reduce nitrogen oxides,

and multiclone with ESP to control PM emissions Equipped with one 30,40 0 ft 3 fuel storage bin

, 2 hog fuel bins, 2 wood chip fuel bins

Conveyance System 2 Cyclones with combined flow rate of 51.004 scfm
1 7,118 ft 2 MAC p ulse Jet Baghouse with 300 hp Blower 1 35” x 45” Rotary Airlock

1 Buhler en

- masse, 19”, 22 tph Conveyor 2 Overhead Storage Bins with enclosed sides

Spray Unit Closed loop unit equipped with integrated, negative pressure, mist collection system and 65’ exhaust stack

Wood Chip Loading Facility 1 p latform truck dumper 1 Wood chip conveying system with dust containment

hood

1 200 hp Rader blower

7 De

- greasing Tanks Non

- solvent based Gasoline Storage Tank Above ground with 10,000 gallon capacity Painting Operation



## 5

. Emissions from the P roposed P roject

The PSD program is intended to protect air quality in “attainment areas”, which are areas that meet the National Ambient Air Quality Standards (NAAQS). Table 5

- 1 describes

which pollutants are covered by the PSD program with in the SCAQMD

. The U.S. EPA is respons ible for issuing PSD permits for pollutants in attainment with the NAAQS in the SCAQMD. As illustrated in Table 5

- 1 , SCAQMD is attainment/ unclassifiable for each NAAQS,8 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 5

- 1 : NAAQS Attainment Status for SCAQMD

Pollutant Attainment Status Permit p rogram Lead (Pb) Attainment PSD Nitrogen Dioxide (NO 2 ) Attainment PSD

Sulfur Dioxide (SO 2 ) Attainment PSD
Carbon Monoxide (CO) Attainment PSD

Sulfuric Acid Mist ( H 2 SO 4 ) n/a 1 PSD
Particulate Matter (PM) n/a 1 PSD

Particulate Matter under 2.5 micrometers diameter (PM 2.5 ) Attainment PSD

Particulate matter under 10 micrometers diameter (PM 10 ) Attainment PSD

Ozone Attainment PSD
Greenhouse Gases (GHG) n/a 1 PSD

The PSD program (40 CFR 52.21) applies to "major" new s ources of attainment pollutants or “major modifications” at existing major sources of attainment pollutants

. SPI

- Anderson is an existing PSD major source proposing to modify its existing PSD permit in order to construct the equipment detailed in Table 4

- 1.



## 6

. Applicability o f the Prevention of Significant Deterioration Regulations

The estimated emissions in Table 4 shows that the proposed construction will be a major

modification for NO

x , CO, PM

, PM 10 and PM 2.5

. The annual emission data in Table 6

- 1 are based on the applicant’s maximum expected emissions, including emissions from startup and shutdown cycle s . T he applicant assumes that all emissions of PM are of

diameter less than 2.5 microns ( P M 2.5 ), which i s a c onservative estimate as some particulate emissions may be much larger than 2.5 micrometers in diameter

.

Once a modification to an existing major stationary source is considered a major

modification for a PSD pollutant, PSD also applies to any other regulated pollutant that is

emitte d in a significant amount. For our PSD applicability determination we are conservatively assuming that all sulfur oxide emissions are sulfur dioxide (SO 2 )

. The data

in Table 6

- 1 show that emissions of SO 2 , volatile organic compounds (VOC)

, sulfuric acid (H 2 SO 4 ) and lead (Pb) will be less than the significant emission rate. Therefore, PSD does not apply for SO 2

, VOC , H 2 SO 4 and Pb

. Total e stimated emissions of the PSD

regulated pollutants resulting from the emission unit s in this modification are listed in

Ta ble 6

- 1

.

1 There is no national ambient air quality standard (NAAQS) for PM, H 2 SO 4 or GHG. However, in addition to other pollutants for which no NAAQS have been set, PM, H 2 SO 4 and GHG are listed as regulated pollutant s with a defined applicability threshold under the PSD regulations (40 CFR 52.21).9 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 6

- 1: Estimated Emissions and BACT Applicability 2

Pollutant Estimated Annual

Emissions (tpy) Significant Emission

Rate (tpy) Does

BACT apply?

CO 472 100 Yes

NO

x 267 40 Yes

PM 4 2.1 25 Yes

PM 10 4 2.1 15 Yes

PM 2.5 4 2.1 10 Yes

VOC 34. 9 40 No

SO 2 10.3 40 No

H 2 SO 4 4.2 7 No

Lead 0.03 0 .6 No

CO 2 e 420,137 (Total)

3 8, 379 (nondeferred) CO2e: 75,000 (subject to regulation)

Mass: 0 (significant) No 3



## 7

. B est A

vailable C ontrol T

echnology

This c hapter describes the Best Available Control Technology (BACT) for the control of CO, NO

x , PM

, PM 10 and PM 2. 5 emissions from this facility. Section 169(3) of the CAA

defines BACT as follows :

"The term ' best available control technology' means an emission limitation based on the maximum degree of reduction of each pollutant subject to regulation under the Clean Air Act emitted from or which results from any major emitting facility, which the permitting authority, on a case

- by

- case basis, taking into account energy, environmental, and economic impacts and other costs, determines is achievable through application of production processes and available methods, systems, and techniques, including fuel cleaning or treatment or innovative fuel

co mbustion techniques for control of each such pollutant. In no event shall application of BACT result in emissions of any pollutants which will exceed the emissions allowed by any applicable standard established pursuant to section 111 (NSPS) or 112 (NESHA PS) of the Clean Air Act. "

2 Annual e missions e stimates differ from the PSD Application submission by SPI and Environ. EPA calculated annual emissions estimates at worst case annual heat input of 468 MMB t u /hr, not 425 MMBtu/hr, and the CO BACT limit was revised to 0.23 lb/MMBtu. (See SPI Annual Emissions Memo to file)

3 Although the proposed modification identifies an increase in GHG emissions that exceeds the “subject to regulation” threshold of 75,00 0 tpy CO 2 e and GHG significance rate of 0 tpy, EPA’s Deferral for CO 2 emissions from Bioenergy and Other Biogenic Sources under the Prevention of Significant Deterioration and Title V p rograms (76 FR 43490 July 20, 2011) applies to this project. Since the non

- deferred GHG emissions for this project are 38,252 tpy CO 2 e, the modification is not subject to BACT for GHG. See Appendix A for relevant emissions

calculations and further discussion.10 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 In accordance with 40 CFR 52.21(j), a new major stationary source is required to apply BACT for each regulated NSR pollutant for which its P TE exceeds significan ce thresholds . BACT is defined as “an emission limitation (includi ng a visible emission standard) based on the maximum degree of reduction of each pollutant subject to regulation under the Act ... which the Administrator, on a case

- by

- case basis, taking into account energy, environmental, and economic impacts, and other costs, determines is achievable for such source.” BACT must be at least as stringent as any applicable New

Source P erformance Standards (NSPS) under 40 CFR P art 60 or National Emission

Standard for Hazardous Air P ollutants (NESHAP) under 40 CFR P art 61. EPA outlines the process it will use to do this case

- by

- case analysis (referred to as “top

- down” BACT analysis) in a June 13, 1989 memorandum. The top

- down BACT analysis is a well established procedure that the Environmental Appeals Board (EAB) h as consistently

followed in adjudicating PSD permit appeals

. See, e.g., In re Knauf, 8 E.A.D. 121, 129

- 31 (EAB 1999); In re Maui Elect ric, 8 E.A.D. 1, 5

- 6 (EAB 1998)

.

In brief, t he top

- down process requires that all available control technologies be ranked in descending order of control effectiveness. The PSD applicant first examines the most stringent technology. That technology is established as BACT unless it is demonstrated that technical considerations, or energy, environmental, or economic impac ts justify a conclusion that the most stringent technology is not achievable for the case at hand. If the most stringent technology is eliminated, then the next most stringent option is evaluated

until BACT is determined. The top

- down BACT analysis is a ca se

- by

- case exercise for the particular source under evaluation. In summary, the five steps involved in a top

- down

BACT evaluation are:

1. Identify all available control options with practical potential for application to the specific emission unit for the regulated pollutant under evaluation;

2. Eliminate technically infeasible technology options;

3. Rank remaining control technologies by control effectiveness;

4. Evaluate the most effective control alternative and document results; if top option is not selected as BACT, evaluate next most effective control option; and

5. Select BACT, which will be the most stringent technology not rejected based on technical, energy, envi ronmental, and economic considerations.

BACT is required for NO

x , CO, PM

, PM 10 , and PM 2.5 for the new proposed emission

units

. Table 7

- 1 lists the BACT determinations for NO

x , CO, PM

, PM 10 , and PM 2.5 from

the proposed boiler and emergency engine , and PM

, PM 10 , and PM 2.5 from the cooling

tower. For the purposes of this determinatio n, all NO

x emissions will be treated as NO 2.11 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 7

- 1: Summary of BACT Limits 4

Unit NO

x CO PM PM 10 PM 2.5

Boiler ( 4 68 MMBtu/hr ) 0.15 lb/MMBtu

( 3

- hour block a verage )

0.13 lb/MMBtu ( 12

- month rolling average ) 0.23 l b/MMBtu ( 3

- h our block

average ) 0.02 lb/MMBtu

( 3

- hour block

average ) 0.02 lb/MMBtu

( 3

- hour block

average ) 0.02 lb/MMBtu

( 3

- hour block

average )

Emergency Engine ( 256 hp ) 0.8 lb/hr

( hourly average ) 6.11 lb/hr ( hourly average ) 0.03 lb/hr

( hourly average ) 0.03 lb/hr

( hourly average ) 0.03 lb/hr

( hourly average )

Cooling tower n/a n/a 0.251 lb/hr, ( hourly average ) 0.251 lb/hr,

( hourly average ) 0.251 lb/hr

( hourly average )



### 7 .1

. BACT for a New Boiler at a Lumber Facility

The SPI

- Anderson facility will install and operate a new boiler to support lumber operations at the sawmill and to sell electricity to the grid. The new boiler will have a maximum heat input capacity of 468 MMBtu/hr. The boiler is subject to BACT for NO x , CO, PM

, PM 10 , and PM 2.5 . A top

- down BACT analysis for each pollutant has been performed and is summarized below.



### 7 .1.1

. Oxides of Nitrogen

NO

x is for med at high temperature s during combustion when nitrogen in the combustion

air or bound in the fuel combines with oxygen to form NO. Depending on condition s in the exhaust stream, some portion of the NO will react to form NO 2

. For the purposes of this analysis and the permit, all NO

x is assumed to form NO 2

.

Step 1

- Identify All Control Technologies A number of existing boiler designs support the combustion of biomass for purpose of electricity generation of this megawatt capacity

. Therefore, in identifying all possible control technologies, the BACT analysis will initially begin with the discussion of two boiler design alternatives.

A significant distinction in boiler design for this purpose can be characterized by the biomass combustion process that occurs within the boiler’s combustion chamber. Biomass boilers can be classified as either being stoker or fluidized bed. Stoker boiler

means a boiler unit consisting of a mechanical ly operated fuel

- feeding mechanism which

includes a stationary or moving grate to support the burning of fuel and admit under

- grate air to the fuel, an overfire air system to complete combustion, and an ash discharge system. This definition of stoker inclu des air swept stokers. Fluidized bed boiler means a boiler utilizing a fluidized bed combustion process that is not a pulverized coal boiler.
Fluidized bed combustion means a process where a fuel is burned in a bed of granulated particles, which are maintained in a mobile suspension by the forward flow of air and

combustion products

.

B oiler design technologies include , but are not limited to, the following :

4 SPI

- Anderson must keep all records of all testing, fuel use, and fuel testing requirements for a period of five (5) years and must report excess emissions to EPA on a semiannual basis.12 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Stoker

- including vibrating, traveling grate, etc.

Fluidized b ed

- including pressurized or atmospheric, such as bubbling bed, circulating,

etc.

In addition to the boiler design, t he available inherent NO

x control technolog y include s : Good combustion practices

In addition to the inherent available control technolog y , the add

- on NO

x contr ol technologies include:
Dry Low

- NO

x burner (DLN)

Selective non

- catalytic reduction (SNCR) Selective Catalytic Reduction (SCR) Regenerative SCR (RSCR)

SCR Variants

EMx TM system (formerly SCONOx)

Step 2

– Eliminate Technically Infeasible Options

Boiler Design Alternatives

For the proposed boiler to service SPI

- Anderson ’s existing primary lumber business and consume the wood from SPI’s other locations, the proposed boiler design must be able to reliably operate under various conditions. Furthermore, SPI has not entered a binding power purchasing agreement with consistent base load electricity demand. With daily

variations in renewable energy demand and the sawmill’s steam requirements , the new

boiler at the Anderson facility may have to var y steam production between 20% and

100 % of full load capacity

. I f electricity demand decreases or the turbine and/or generator malfunction, the boiler may need to significantly reduce the amount of steam it generates.

However, periods of reduced steam dem and do not necessarily coincide with reduced

sawmill requirements . If other pieces of the co generation unit are not operating, and the boiler cannot reduce steam output, then the boiler m ust be shut down, rendering some of

the lumber

- drying kilns inoperabl e . If the kilns are unable to operate , lumber cannot be dried and the existing lumber facility may be unable to function normally. Moreover, as

the modification will not expand beyond the current physical footprint of the SPI

Anderson facility, the space for stockpiling wood may be exhausted while the kilns are inoperable , thus causing portions of the sawmill to be shut down. Therefore, any boiler chosen for the proposed modification must reliably function at low steam

- load conditions

in order to accommod ate SPI

- Anderson ’s existing lumber operation.

The proposed boiler at the SPI

- Anderson facility must be gua ranteed to reliably operate at steam loads ranging from 50,000 lbs/hr to 250,000 lbs/hr

. This variability i n projected steam output is also caused by uncertainty in biomass fuel moisture and the variety of wood products and trimmings produced by SPI ’s other nearby facilities. As Environ,

SPI ’s project consultant, state d in its January 23, 2012 letter 5

, “... several examples of

5 Albright, Eric “Supplemental Control Technology Analysis Sierra Pacific Industries Biomass

- Fired Cogeneration Project Anderson, California ” Letter to Gerardo Rios. 23 Jan. 201213 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 biomass

- fired fluid ized

- bed boilers [are] in operation. However, most, if not all, produce steam solely for power generation, and do not provide process steam. Steam used to heat industrial processes is often subject to varying demand

, especially for batch processes (e.g., l umber dry kilns). The primary reason for fluidized bed boiler designs lack of representation among biomass

- fired process steam generators is the inability to operate in

a turndown mode. ” The process steam flexibility that SPI desires for its sawmill

operat ions cannot reliably or effectively be accommodated by a fluidized bed boiler. Therefore, a fluidized bed boiler is technically infeasible for this project.

EMx TM To date, EMx TM h as been designed and used only on small to medium sized natural gas

fired stationary turbines for demonstration purposes. We are not aware of any biomass boiler applications currently operating with EMx, or any permit application for a biomass

boiler that proposes to use the EMx to control NO

x emissions.

T he EMx TM s ystem is sensitive to sulfur in the exhaust, which can degrade the performance of the system. While wood fuels are not generally considered high

- sulfur fuels, the AP

- 42 SO 2 emission factor for w ood

- fired boilers is 0.025 lb/MMBtu, which is equivalent to about 7.2 lb/hr of SO 2 . Natural gas, the combustion fuel most commonly

associated with EMx TM applications, has maximum sulfur limit of one grain per 100 standard cubic feet (gr/scf) of gas in Cali fornia, where EMx TM has been applied. On a heat input basis, this is equivalent to an SO 2 emission rate of 0.43 lb/hr.

The lack EMx implementation for biomass boilers , combined with the sensitivity to sulfur suggest that EMx TM is technologically infeasibl e as a control technology for controlling

NO

x emissions from a biomass

- fired boiler . Therefore we do not consider this technology

achievable for biomass

- fired boilers at this time

.

DLN Burner

With two or more DLN burners , the biomass combustion fuel would need to be pulverized and burned in suspension using wall

- mounted burners . This presents a significant departure from SPI’s proposed boiler design where combustion occurs on a moving grate . DLN burners are designed to limit the amount of fuel

- bo und nitrogen that

is converted to NO

x during combustion, and are generally suited to boilers that burn wood waste containing a high percentage of resins, such as the waste from medium density fiberboard, plywood, or veneer operations. The emission rate wit h DLN burners is projected to be 0.35 lb/MMBtu.

Good combustion practices

A modern biomass

- fired boiler furnace, operated with computerized controls to ensure good combustion practices would result in a NO

x emissio n limit between 0.2 0 lb/MMBtu

and 0. 26 l b /MMBtu. The boiler design proposed by SPI would emit 0.2 0 lb/MMBtu when utilizing only good combustion practices to reduce NO

x emissions. Good combustion practices are the result of proper boiler maintenance and design

.

All of the listed add

- on technologies described below are technically feasible for th e proposed project

.14 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 SNCR (Selective N on

- C atalytic R eduction )

With SNCR , ammonia is injected through a mmonia

- injection nozzles which are positioned in the furnace and use d at relatively high temperatures to promote the reaction

of NO

x with ammonia. SNCR system s are often incorporated into the overall boiler design, and can be located at the furnace exit because they do not rely on a catalyst

. Catalysts may be problematic for biomass stok ers because catalyst beds are susceptible to plugging from PM in the flue gases. SNCR is a commonly

- employed add

- on NO

x control technology for biomass

- fired boilers. Over a long term basis the emission rate from a design utilizing a n SNCR system is project ed to be 0.13 lb/MMBtu of NO

x .

SCR (Selective Catalytic Reduction)

, RSCR (Regenerative Selective Catalytic Reduction) and other catalyst variants An SCR system is similar to SNCR in that a reagent reacts with NO

x to form nitrogen

and water; however a catalyst matrix is used to allow the reduction reaction to take place at lower temperatures. There are several SCR and SCR variant systems that have been permitted for use on biomass boilers in various configurations along the exhaust stream. Although m any biomass boilers have begun to be permitted with SCR and SCR variant systems, the verifiable data and the demonstrated effectiveness of SCR systems at
constructed biomass facilities remains limited. Moreover, t he projected NO

x emissions

from those facil ities permitted with SCR vary considerably

.

The RBLC contains references to p ermitted RSCR and SCR systems with emission limits

as low as 0.0 3 lb/MMBtu of NO

x on a 12

- month rolling basis as seen in Table 7.1

- 1

. T he

lowest referenced NO

x emissions limit that EPA has discovered in its review from constructed biomass power plants is McNeil Generating Station with a verified 2010 quarterly calendar emission rate of 0. 75 lb/MMBtu of NO

x . However, the short term

emission limit for the main boi ler at McNeil while burning wood shall not exceed 0.23

lb/MMBtu. The installation of th at SCR system was permitted through a permit

amendment. T he facility “proposed to install and operate a selective catalytic reduction (SCR) system in order to reduce the facility’s emissions of NO

x . The reduced NO

x emissions are required for the Facility to qualify for Class 1 renewable energy credits (RECs) in New England.” 6 Aspen Power’ s Lufkin Generating Station in Texas has constructed, however, EPA has not been able to verify if this NO

x emissions limit has been demonstrated in practice over the shorter averaging period.

Step 3

– Rank Control Technologies A summary of recent NO

x BACT determinations for biomass

- fired boilers is provided in

T able 7.1

- 1

. The applicant has proposed a NO

x limit of 0.13 lb/MMBtu, based on a 12

- month rolling average and 0.15 lb/MMBtu, based on a 3

- hour block average.

6 McNeil Generating Station Title V Permit15 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 7.1

- 1 : Summary of Recent NO

x BACT Determinations for Similar Units

* McNeil Station is not the result of a BACT Determination as discussed in NO

x Step 4 below.

The remaining technologically feasible control technologies ranked in decreasing order of

effectiveness are:

Table 7 .1

- 2 : Ranking of NO

x control technologies

NO

x control technology Emission Rate (lb NO

x /MMBtu)
SCR, RSCR and variants 0.06

SNCR 0.13 Good combustion practices 0.20

DLN burner 0.35

Step 4

– Economic, Energy and Environmental Impacts

SPI has submitted cost

- effectiveness estimates comparing SCR and SNCR with their projected NO

x emission rates and the cost of installation and operation of the respective control technologies

. SPI assumed that the new boiler’s emission rate with the use of

SCR for the cost

- effectiveness esti mates would be lower than any emissions level that EPA has found to be demonstrated in practice. SPI presumes that the rate of NO

x emission s with SCR and SNCR are 0.06 lb/MMBtu and 0.13 l b/MMBtu respectively.

The average cost per ton controlled from SCR and SNCR technologies at the proposed

emission levels are $ 4,596 and $1, 417 respectively. However, the incremental cost

effectiveness separating the two technologies reveals that the cost of each additional ton

of NO

x removed by the implementation of SCR a t the projected cost and emission rate is $ 9, 191

. EPA reviewed the cost estimates provided in the PSD permit modification application and determined that it considered the appropriate operation and capital costs but calculated improper potential to emit emissions estimates. The additional expense of the SCR equipment is due to a higher capital cost in primary equipment along with higher operational, maintenance and lost revenue costs.16 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Although the McNeil Generating Station has demonstrated a lower NO

x emission limit on a calendar quarterly basis, it has a short term NO

x emission limit of 0.23 lb/MMBtu. Moreover, the possible economic incentives of the Class 1 Renewable Energy Credits in New England are difficult to quantify and not available to SPI

- Anderson. This may allow SCR system to be more economically feasible for McNeil Generating Station and other proposed systems in the New England area than for SPI

- Anderson in California

.

EP A does not anticipate additional significant environmental or energy impacts from employing the SNCR or SCR technology. Both systems use ammonia as a reagent: anhydrous ammonia, aqueous ammonia, or urea mixed with water (which hydrolyzes in

the hot exhaust to form ammonia). In the case of aqueous ammonia or urea mixed with water, additional fuel must be combusted to evaporate the water associated with the reagent. Moreover, energy is required to operate the injectors used by either technology

to introduce t he reagent in to the exhaust. With either technology, the exhaust leaving the boiler stack will contain some small quantity of ammonia.

Step 5

– Select BACT SPI has proposed the most stringent NO

x emissions limit for stoker boilers with SNCR

demonstrated i n practice. Although additional tons of possible NOx emissions may be controlled by the installation of an SCR system, the increased annual costs of an SCR system or other variants versus the SNCR system is cost prohibitive at this existing

sawmill f acilit y.

Based on a review of the available control technologies for NO

X emissions from biomass boilers selected for this operation , we have concluded that BACT for the stoker boiler to perform this purpose is 0 .15 lb/MMBtu ( 3

- hour block average ) and 0 .13 lb/ MMBtu ( 12

- month rolling average ) employing SNCR

. We are also requiring a lb/hr mass emission

rate of 60.8 lb/hr ( 3

- hour block average ) during normal operations.



### 7 .1. 2

. Carbon Monoxide

Carbon monoxide (CO) occurs due to incomple te combustion of fuel in th e boiler’s
combustion chamber, and in the Low

- NO

x b urners when they are operated.

Step 1

- Identify All Control Technologies A number of existing boiler design alternatives support the combustion of biomass at this megawatt capacity. Therefore, in identifying all possible control technologies, the BACT analysis should begin with a discussion of boiler design alternatives.

In addition to the boiler design, the available inherent CO control technology includes: Good combustion practices

In addition to the inherent available control technolog y , the add

- on CO control technologies include:

EMx TM Catalytic oxidation17 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Step 2

– Eliminate Technically Infeasible Options Boiler Design Alternatives As discussed in the BACT analysis for NO

x in Section 7.1.1 of this document , fluidized bed boiler designs were found to be infeasible for this project.

EMx TM As discussed in the BACT analysis for NO

x in Section 7.1.1 of this document

, EMx h as been design ed and used only on small to medium sized natural gas

- fired stationary turbines for demonstration purposes. EMx has not been demonstrated in practice for biomass boilers and we do not consider this technology achievable for biomass boilers at

this time.

Good combustion practices

A modern biomass

- fired boiler furnace, operated with computerized controls to ensure good combustion practices would result in a CO emissio n limit of between 0.23 and 0.35

l b/MMBtu. The boiler design proposed by SPI would emit 0.2 3 lb/MMBtu of CO when utilizing only good combustion practices to reduce CO emissions. Good combustion practices are a technically feasible technology for controlling CO emissions from

biomass

- fired boilers.

T he add

- on technolog y described below is techni cally feasible for this project.

Catalytic Oxidation Catalytic oxidation can be used to control CO when a matrix coated with noble metals facilitates the conversion of a pollutant, such as CO to CO 2

. Catalytic oxidizers operate in a temperature range of approximately 650°F to 1,000°F. At lower temperature the CO conversion efficiency falls off rapidly. Although technically feasible, catalytic oxidation

has not been reliably demonstrated for biomass bo ilers. SPI projects that with successful implementation of a catalytic oxidizer the facility may be able to emit 0.1 lb/MMBtu of

CO

. Other permitted facilities that have not constructed have been permitted at CO

emission levels as low as 0.075 lb/MMBtu of CO.

Step 3

– Rank Control Technologies A summary of recent BACT determinations for biomass

- fired stoker boilers with CO emission limits is provided below. The applicant has proposed a CO limit of 0. 23

lb/MMBtu ( 3 hour block average )

. SPI has proposed the most stringent emission limit of

constructed biomass stoker boilers that EPA was able to find in its control technology

review

.18 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 T able 7.1

- 3 : Summary of Recent CO BACT Determinations for Similar Units

However, t he new biomass boiler SPI

- Anderson has not begun construction at this time. Based on this information, oxidation catalyst is being evaluated as the most stringent

control. The remaining feasible control technologies ranked in decreasing order of

effectiveness are:

Table 7.1

- 4 : Ranking of CO control technologies

CO control technology Emission Rate (lb CO /MMBtu) Catalytic Oxidation 0.10 Good combustion practices 0.23

Step 4

– Economic, Energy and Environmental Impacts

SPI has submitted cost

- effectiveness estimates comparing catalytic oxidation and good combustion practices with their projected CO emission rates and the cost of installation and operation of the respective control technologies

. SPI assumed that the new boiler’s emission rate with the use of an oxidation catalys t for the cost

- effectiveness estimates would be lower than any emissions level that EPA has found to be demonstrated in practice. SPI has presumed that the rate of CO emissions with catalytic oxidation and good combustion practices are 0.1 lb/MMBtu and 0.2 3 lb/MMBtu respectively.

As good combustion practices are the result of proper boiler maintenance and the boiler design, SPI only assessed the incremental cost

- effectiveness separating the two technologies . T he cost of each additional ton of CO removed by the implementation of catalytic oxidation at the projected cost and emission rate is $8, 930

. EPA reviewed the cost estimates provided in the PSD permit modification application and determined that it considered the appropriate costs but calculat ed improper potential to emit emissions

estimates. The additional expense of the catalytic oxidizer is due to a higher capital cost in primary equipment along with higher operational, maintenance and lost revenue costs.

Step 5

– Select BACT SPI has propos ed the most stringent CO emissions limit for stoker boilers demonstrated in practice. Although additional tons of possible CO emissions may be controlled by the19 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 installation of an oxidat ion catalyst, SPI has expressed significant doubts that the catalyst

w ill be able to reliably and effectively control CO given its fuel type and operation. In addition, the increased annual costs of an oxidation catalyst present a significant financial

burden at this existing sawmill facility.

Based on a review of the available control technologies for CO emissions from biomass

boilers selected for this purpose , we have concluded that BACT for the stoker boiler to perform this operation is 0.23 lb/MMBtu ( 3

- hour block average ) employing good

combustion practices . We are also requiring a lb/hr mass emission rate of 108 lb/hr ( 3

- hour block average ) during normal operations.



### 7 .1. 3

. Particulate Matter

- PM

, PM 10 

### , PM 2.5

P articulate emissions are the result of unburned solid carbon (soot), unburned vapors or gases that subsequently condense, and unburn ed portion s of fuel (ash)

. Because the applicant has assumed that all particulate emissions from the boiler are PM 2.5 , the BACT analyses for PM

, PM 10 and PM 2.5 have been combined. Additionally, the analysis

evaluates total particulate emissions

– condensable and filterable.

Step 1

– Identify All Control Technologies The following inherent control options for PM

, PM 10 and PM 2.5 emissions include:

Low sulfur fuels for normal operation , and/or pipeline natural gas for startup and

shutdown Good combustion practices

The available add

- on PM

, PM 10 , PM 2.5 control technologies include: Cyclones (including multiclones)

Venturi scrubber lectrostatic precipitator (ESP) Baghouse/ F abric filter.

Low sulfur fuels

The w ood fuels to be used predominantly during normal operation along with the pipeline natural gas to be used during startup and shutdown are not genera lly considered high

- sulfur fuel s

.

Good combustion practices

A modern biomass

- fired boiler furnace, o perated with computerized controls to ensure good combustion practices

, would result in a PM

, PM 10 and PM 2.5 emissio n limit between

0. 33 lb/MMBtu and 0. 56 l b/MMBtu , based on U.S. EPA ’s AP

- 42 Compilation of Air

P ollutant Emission Factors for wood residue combustion in boilers.

The add

- on technologies described below are technically feasible for this project.

Cyclones or Multiclones20 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Cyclones or multiclones, a series of single cyclone particulate matter separators, operate

in a similar manner. An inlet gas stream enters the cyclone or multiclone at an angle causing the gas stream to spin rapidly . The resulting c entrifugal forces push the larger particulate into and down along the cyclone walls for collection.

Venturi Scrubbers

Venturi scrubbers reduce particulate by introducing liquid into a converging section of a gas stream. The particulate in the gas stream is removed when it mixes with the liquid and forms tiny droplets that are collected and removed. With gas

- side pressure drops

e xceeding 15 inches of water, particulate collection efficiencies of 85% or greater have been reported for venturi scrubbers operating on wood

- fired boilers.

lectrostatic precipitator (ESP) Electrostatic precipitators use electrostatic forces to separate particulate from the gas

stream. When applied to wood

- fired boilers, ESPs are often used downstream of mechanical collector pre

- cleaners which remove larger

- sized particles. Collection

efficie ncies of 90

- 99% for particulate have been observed for ESPs oper ating on wood

fired boilers.

Baghouse/ Fabric filter Baghouses or f

abric filters have had limited applications to wood

- fired boilers. The principal drawback to fabric filtration is a fire danger arising from the collection of combustible carbonaceous fly ash. Although some fabric filters have demonstrated lower collection efficiencies, most fabric filter p article collection efficiencies are 90

- 99%, equivalent to ESPs.

Step 2

– Eliminate Technically Infeasible Options All of the available control options identified in Step 1 are technically feasible. Cyclones

are often used in conjunction with the other control technologies listed above.

Step 3

– Rank Control Technologies A summary of recent BACT determinations for biomass

- fired stoker boilers with PM

, PM 10 , and PM 2.5 emission limits is provided below. The applicant has proposed a total PM, including filterable and condensable particulate, emission limit of 0.02 lb/MMBtu ( 3

hour block average ) utilizing an ESP preceded by a multiclone

. SPI has proposed t he most stringent PM

, PM 10 , and PM 2.5 emission limit of biomass stoker boilers that have

constructed.21 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 7.1

- 5 : Recent PM

, PM 10 , PM 2.5 BACT Determinations for Similar Units

SPI has estimated that the use of a multiclone followed by an ESP or baghouse will be equally effective in the control of particulate matter from the proposed boiler. The feasible control technologies ranked in decreasing order of effectiveness are:

Table 7.1

- 6 : Ranking of PM / PM 10 / PM 2.5 control technologies

PM/ PM 10 / PM 2.5 control technology Emission Rate (lb PM / PM 10 / PM 2.5 per MMBtu)

ESP with multiclone 0.02 Baghouse with multiclone 0.02

Venturi Scrubber 0.30

Low sulfur fuels 0.33

G ood Com bustion p ractices 0.33

- 0.56

Step 4

– Economic, Energy and Environmental Impacts In EPA’s review, three biomass stoker facilities have proposed lower rates of total particulate emissions than SPI

- Anderson. The 0.01 lb/MMBTu particulate emissions

limit for Laidlaw Berlin Biopower was only for filterable particulate, not total p articulate, and the project has been canceled. The succeeding total particulate emission levels in

Table 7.1

- 5 for 0.18 lb/MMBtu and 0.19 lb/MMBtu of total particulate have been proposed but have not been de monstrated in practice. Moreover, the increased l evels of control for total particulate in both of cases were proposed with different control technologies.

In our review, EPA found that the lowest achievable total particulate emissions demonstrated in practice from biomass stoker boilers have been achie ved with fabric

filter s or ESP s

. With equivalent levels of control, SPI considered the potential economic,

ene rgy and environmental impacts from each control system. Baghouses require additional energy to over c ome increased pressure drops that occur during the control of particulate. ESP systems use electricity to create an electric field, but typically have lower overall energy requirements th a n baghouses. As stated earlier, fabric filters may also have an increased fire danger at biomass facilities due to the carbonaceous fly ash.

Step 5

– Select BACT Based on a review of the available control technologies for PM

, PM 10 and PM 2.5 emissions from biomass boilers selected for this purpose , we have concluded that BACT22 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 for the stoker boiler to perform this operation is 0.02 lb/MMBtu ( 3

- hour block average ) using a multiclone and ESP . We are also requiring a lb/hr mass emission rate of 9.4 lb/hr ( 3

- hour block average ) during normal operations.



### 7.1.3. Startup and Shutdown BACT L imits The boiler startup process begins by igniting a pile of biomass fuel on the grate and firing two 62.5 MMBtu/hr natural gas burners located near the steam tubes

. After approximately 12 hours, the boiler will be at about 50 % of full load and attain a sufficient steady state temperature supporting the activation of the SNCR system . Once

the boiler has reached normal operating temperature, as specified by the boiler manufacturer, startup has concluded and the boiler will operate under normal conditions. Shutdown begins when the fuel feed is curtailed and the unit begins cooling. Shutdown ends when the recorded temperature at the superheater outlet reaches 150 ° F and remains so for at least one hour, or 24 hours has elapsed since the shutdown process began. Add

on particulate cont rols will be operating during all phases of startup and shutdown. The SNCR will be operating at all appropriate temperature ranges, as specificed by the SNCR manufacturer. During startup and shutdown, the generator shall be disconnected from the

electrical grid.

Table 7.1

- 7 lists the startup and shutdown BACT emission and averaging times

. Table

7.1

- 7 also lists the maximum amount of time for a startup and shutdown event.

Table 7.1

- 7 : BACT for Startup and Shutdown

Pollution and Duration Limits

NO

x (hourly average) 70.2 lb/hr

CO (hourly average) 108 lb/hr

PM

, PM 10 , PM 2.5 (24 hour average) 8. 93 lb/hr

SO 2 (hourly average) 2.34 lb/hr

Maximum Duration 24 hours



### 7.2 BACT for Emergency Engine

The project includes a 256hp (190kW) natural gas

- fired emergency engine to run the emergency boiler recirculation pump . The limited operation of this unit result s in

minimal annual emission rates. This equipment is subject to BACT for NO

x , CO, PM

, PM 10 , PM 2.5 . A top

- down BACT analysis has been performed and is summarized below.



### 7.2.1 NO
x 

### , CO, PM

, PM 10 

### , PM 2.5 

### Emissions Step 1

-- Identify all control technologies The control options for NO

x emissions from engines include SCR, NO

x reducing catalyst,

NO

x adsorber, catalyzed diesel particulate filter, catalytic converter, and oxidation catalyst. A catalytic converter and oxidation catalyst are also control options for CO23 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 emissions. A particulate filter/trap can be added f or the control of PM

, PM 10 , and PM 2.5 emissions,

Unlike the main biomass boiler

, the emergency engine will be limited in operation and is required to be certified in compliance with NSPS requirements, including emission limits, upon purchase. A review of other BACT determinations was not performed because it is very unlikely that a mor e detailed review would change the final

determination due to the limited use and annual emission rates associated with the proposed limits. The potential to emit for all criteria pollutants subject to BACT review is less than 200 lbs/yr.

Different types of engines have different emission requirements based on the type of engine being purchased. Engine manufacturers may need to employ some of the control technologies identified above in order to comply with the NSPS emission limits, depending on the type o f engine and the applicable limits. The applicant is proposing to

install an emergency engine for infrequent recirculation pump needs

. As a result, SPI must purchase engines that comply with the NSPS and meet the emission requirements for emergency engines . However, we note that t he applicant could purchase engines that

meet the NSPS standards for non

- emergency engines, which have more stringent limits, and operate them as emergency engines. As a result, this review identifies the control technologies to be :
NSPS

- compliant emergency engine Engine that meets NSPS for non

- emergency engines Limiting use (limits on the hours of operation)

Step 2

– Eliminate technically infeasible control options All of the control technologies identified are assumed to be technically feasible.

Step 3

– Rank remaining control technologies The available control technologies are ranked according to control effectiveness in Table

7.2

- 1

.

Table 7.2

- 1: NSPS Limits for Engines

Engine Type (190kW) NO

x +NMHC (g/kW

- hr) CO

(g/kW

- hr) PM

(g/kW

- hr)

Non

- emergency engine 0.59 3.5 0.02 Emergency engine 4.0 3.5 0.20

Step 4

– Economic, Energy and Environmental Impacts Due to economic impacts and limited environmental benefit, the use of add

- on controls

for the emergency engine and purchasing an engine that meet NSPS standards for a non

emergency engine and operating it as an emergency engine would be impractical in this

case. This is illustrated in Table 7.2

- 2 by the potential emissions from the emergency engine (based on 10 0 hours of operation per year and complying with the NSPS for

emergency engines ). Requiring the additional reductions in emissions that would be24 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 gained by use of engines that meet NSPS standards for non

- emergency engines would have very little environmenta l benefit and not justify the cost.

Table 7.2

- 2 : Summary of PTE for 190 kW Emergency Engine

Pollutant Emergency Engine (tpy)

NO

x 0.0 39

CO 0. 306
PM, PM 10 , PM 2.5 0.00 11

Step 5

– Select BACT

Based on a review of the available control technologies, we have concluded that BACT is

limit ing the hours of operation and the emission limits listed in Table 7.2

- 3 based on a 3

- hour average. It is assumed that newly purchased engines would be the most energy efficient available and that operating in compliance wi th NSPS requirements will ensure that each engine is properly maintained and as efficient as possible.

Table 7.2

- 3 : Summary of BACT for 190 kW Emergency Engine

Engine Type NO

x +NMHC

(g/kW

- hr) CO

(g/kW

- hr) PM

(g/kW

- hr) Emergency engine 4.0 3.5 0.20



### 7

. 3

. BACT for Cooling Towers

The proposed project also requires a cooling tower system to dissipate the heat load into the atmosphere

. The cooling tower system is subject to BACT for PM

, PM 10 , and PM 2.5

. A top

- down BACT analysis has been performed and is su mmarized below. The applicant conservatively assumed PM

, PM 10 and PM 2.5 emissions from the cooling tower were equivalent.

Step 1

- Identify All Control Technologies The following inherent control options for PM

, PM 10 , and PM 2.5 emissions include:

Wet cooling Dry cooling

W et

- Dry Hybrid cooling

Wet cooling Cooling towers are heat exchangers that are used to dissipate large heat loads to the

a tmosphere. They are used as an important component in many industrial and commercial processes needing to dissipate heat. Wet cooling towers rely on the latent heat of water evaporation to exchange heat between the process and the air passing through the cooling tower.

A two

- cell evaporative cooling tower for this project would require a water load 4.24 gall ons per minute per square foot. The expected air velocity is 503 feet per minute. Fugitive particulate emissions would be generated from the cooling tower due to the total

dissolved solids (TDS) in the water.25 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Dry cooling Dry cooling uses an air cooled con denser (ACC) that cools the steam turbine generators’ exhaust steam using a large array of fans that force air over finned tube heat exchangers. The exhaust from the steam turbine flows through a large diameter duct to the ACC

where it is condensed inside the tubes through indirect contact with the ambient air. The heat is then released directly to the atmosphere.

Wet

- D ry H ybrid cooling

Wet

- Dry Hybrid cooling uses wet and dry cooling technologies in parallel, and uses all of the equipment involved in both wet and dry cooling. Hybrid cooling technology divides the cooling function between the wet and dry systems depending on the capabilities of each system under different environmental and operational conditions.

The available add

- on PM

, PM 10 , and PM 2.5 con trol technologies include:

Drift eliminators

Drift Eliminators

D rift eliminators are usually incorporated into the tower design to remove as many droplets as practical from the air stream before exiting the tower. The drift eliminators used in cooling t owers rely on inertial separation caused by direction changes while passing through the eliminators. Types of drift eliminator s include many different configurations and various materials

. The materials may include other features, such as corrugations and water removal channels, to enhance the drift removal further.

Step 2

– Eliminate Technically Infeasible Options All of the available control options identified in Step 1 are technically feasible.

Step 3

– Rank Control Technologies The remaining feasible control technologies ranked in decreasing order of effectiveness are:

Table 7.3

- 1: Ranking of PM / PM 10 / PM 2.5 control technologies

PM/ PM 10 / PM 2.5 control technology Emission Rate (tpy of PM

, PM 10 , PM 2.5 ) Dry cooling 0

Wet

- Dry Hybrid cooling 0.55 7
Wet cooling with 0.0005%

Drift Eliminators 1.10

The applicant has proposed to use wet cooling with DRU

- 1.5 high

- efficiency mist eliminators with a drift loss of less than 0.0005%. This is the equal to the lowest proposed

amount of drift that EPA has found in its review of similar facilities.

7 The applicant did not estimate potential emissions from a wet

- dry hybrid system. We have approximated emissions from such a system to be one

- half of those from a wet cooling system.26 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 EPA did n ot find any sawmill facilities or biomass boilers that use dry cooling or wet

- dry hybrid cooling as an alternative to wet cooling

. As shown in Table 7.3

- 1 the potential impact from the various control options will have a limited effect on the total PM

emis sions from the project . The difference in potential to emit resulting from the cooling

tower options is 1.10 tpy of total PM.

Step 4

– Economic, Energy and Environmental Impacts The use of a dry or hybrid wet

- dry system would reduce the overall efficiency of the facility, due to the additional energy requirements for the wet and hybrid systems. Moreover, dry and wet

- dry c o oling systems are typically more costly than a more conventional wet cooling tower system. On the other hand, the use of wet cooling has a potential environmental impact associated with additional consumption of water

resources.

Step 5

– Select BACT Based on a review of the available control technologies for PM

, PM 10 , PM 2.5 emissions from cooling towers selected for this operation, and the limited amount of total particulate resulting from the cooling tower operation, we have concluded that the proposed boiler can utilize wet cooling.

Utilizing the wet cooling tower option, SPI has elected to use the most stringent control option a vailable, by limiting drift to 0.0005%

. Therefore, BACT for the cooling tower in the proposed modification will be the use of a wet cooling tower with a drift loss of less

than 0.0005%.



## 8

. Air Quality I mpacts

CAA S ection 165 and EPA’s PSD regulations at 40 CFR § 52.21 require an examination of the impacts of the proposed SPI

- A nderson project on ambient air quality. The applicant must demonstrate, using ai r quality models, that the facility’s emissions of

PSD

- regulated air pollutants would not cause or contribute to a violation of (1) the applicable NAAQS, or (2) the applicable PSD increments (explained below in Sections 8.4 and 8.5). These sections of the AAQIR include a discussion of the relevant background data and air quality modeling, and EPA’s conclusion that the project will not cause or contribute to an exceedance of the applicable NAAQS or applicable PSD

increments and is otherwise consistent with PSD requirements governing air quality.



### 8.1 Introduction

8.1.1 Overview of PSD Air Imp act Requirements

Under the PSD regulations, permit applications for major sources must include an air quality analysis demonstrating that the facility’s emissions of the PSD

- regulated air pollutants will not cause or contribute to a violation of the applic able NAAQS or applicable PSD increments. (A PSD increment for a pollutant applies only to areas that meet the corresponding NAAQS.) The applicant provides separate modeling analyses for27 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 each criteria pollutant emitted above the applicable significant emiss ion rate. If a preliminary analysis shows that the ambient concentration impact of the project by itself is greater than the Significant Impact Level (SIL), then a full or cumulative impact analysis is required for that pollutant. The cumulative impact ana lysis includes nearby pollution sources in the modeling, and adds a monitored background concentration to account for sources not explicitly included in the model. The cumulative impact analysis

must demonstrate that the modification will not cause or cont ribute to a NAAQS or

increment violation. If a preliminary analysis shows that the ambient concentration impact of the project by itself is less than the SIL, then further analysis is generally not required. Required model inputs characterize the various emitting units, meteorology, and the land surface, and define a set of receptors (spatial locations at which to estimate concentrations, typically out to 50 km from the facility). Modeling should be performed

in accordance with 40 CFR § 51 , Appendix W

- Gui deline on Air Quality Models (GAQM)

. AERMOD with its default settings is the standard model choice, with CALPUFF available for complex wind situations.

A PSD permit application typically includes a Good Engineering P ractice (GEP) stack height analysis, t o ensure that downwash is properly considered in the modeling, and stack heights used as inputs to the modeling are no greater than GEP height, so as to disallow artificial dispersion from the use of overly tall stacks. The application may also

include ini tial “load screening,” in which a variety of source operating loads and ambient temperatures are modeled, to determine the worst

- case scenario for use in the rest of the modeling.

The PSD regulations also require an analysis of the impact on nearby Class I areas, generally those within 100 km, though the relevant Federal Land Manager (FLM) may specify additional or fewer areas. This analysis includes the NAAQS, PSD increments, and Air Quality Related Values (AQRVs). AQRVs are defined by the FLM, and typica lly limit visibility degradation and the deposition of sulfur and nitrogen. Generally, CALPUFF is the standard model choice for Class I analyses because it can handle visibility chemistry as well as the typically large distances (over 50 km) to Class I are as.

Finally, the PSD regulations require an additional impact analysis, showing the p roject's effect on visibility, soils, vegetation, and growth. This visibility analysis is independent of the Class I visibility AQRV analysis. The additional impact analy sis for the SPI

A nderson project is discussed in Section 9.



### 8.1.2 Identification of SPI

- Anderson Modeling Documentation

The applicant , SPI, submitted numerous documents and materials which comprise the entire modeling analysis

. P SD and ATC p ermit Application ( May 2007 ) contain s the results of the original modeling and most of the Class I analys e s. The updated PSD and ATC Application and associated compact disc ( March 2010 ) contain updated modeling

results

. Response to Incompleteness Determination # 1 (July 2010)

, containing a full impact analysis for compliance with the 1

- hour NO 2 NAAQS and a partial Additional Impacts Analysis. Response to Incompleteness Determination #2 (September 2010)

revisit s the 1

- hour NO 2 NAAQS compliance analysis and provid es monitoring and28 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 meteorology background information. Startup/Shutdown Information (December 2010)

contain s proposed limits on the number of annual startups and shutdowns. Response to Additional Information Request (June 2011) provides further information on proposed

startup and shutdown emission limits. Updated Air Dispersion Modeling Analysis (May 2012) contains modeling files and an updated modeling analysis that reflect s project changes since the March 2010 submittal. Surface Characteristics (June 2012) d escribes the surface characteristics between the meteorology site and the project site as well as modeling receptor network. Background Concentration Information (June 2012) supplies

information regarding the monitoring background concentrations. CALPUFF Modeling

Files (June 2012) contains archived CALPUFF modeling files developed for the original May 2007 PSD application and used in subsequent submittals.



### 8.2. Background Ambient Air Quality

The PSD regulations require the air quality analysis to contain air quality monitoring data as needed to assess ambient air quality in the area for the PSD

- regulated pollutants for which there are NAAQS that may be affected by the source. In addition, for

demons trating compliance with the NAAQS, a background concentration is added to represent those sources not explicitly included in the modeling, so that the total accounts for all contributions to current air quality.

The applicant used ambient air concentratio ns of NO 2 , which were recorded at Manzanita Avenue in Chico 55.5 miles (90 km) south of the facility’s current location . This was the closest and most representative NO 2 monitor to the site. For PM 2.5 background concentrations, the applicant used data fro m a monitor at the Redding Department of Health which is approximately 6.5 miles (10.5 km) northeast from the facility. The applicant took PM 10 background concentrations from Anderson , which is around 6.5

miles southeast from the facility s ite.

Table 8

. 2

- 1 describes the maximum background concentrations (from 2011) of the PSD

regulated pollutants for which there are NAAQS that may be affected by the p roject’s emissions, and the corresponding NAAQS.

Table 8 .2

- 1: Maximum Background Concentrations and NAA QS

P ollutant

, A veraging T ime Background Concentration ( μg/m 3 ) NAAQS ( μg/m 3 )

NO 2 , 1

- hour 62.7 (33 ppb) 188 (100 ppb)

NO 2 , annual 33.1 (17 ppb) 100 (53 ppb)

PM 10 , 24

- hour 42 150

PM 2.5 , 24

- hour 15.3 35

PM 2.5 , annual 5.3 15
CO, 1

- hour 2,976 (2.6 ppm) 40,000 (35 ppm)
CO, 8

- hour 2,404 (2.1 ppm) 10,000 (9 ppm)
Ozone, 8

- hour 71 ppb 75 ppb

Note : The PM 2.5 24

- hr value is 98 th percentile averaged over three years rather than maximum

The NO 2 1

- hr value is 98 th percentile averaged over three years rather than maximum

The Ozone 8

- hour value is the fourth highest 8

- hour concentration averaged over three years29 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 

### 8.3 Modeling Methodology for Class II areas

The appl icant modeled the impact of SPI

- Anderson on the NAAQ S and PSD Class II increments using AERMOD in accordance with GAQM . The modeling analyses included the maximum air quality impacts during normal operations and startups and shutdowns, as well as a variety of conditions to determine worst case
, short

- term a ir impacts.



### 8.3.1 Model selection

As discussed in the PSD Application ( Updated PSD Application , March 2010, p.11pdf15) , the model that the applicant selected for analyzing air quality impacts in Class II areas is AERMOD, along with AERMAP for terrain proce ssing and AERMET for meteorological data processing. This is in accordance with the default

recommendations in Section 4.2.2 on Refined Analytical Techniques in GAQM

.



### 8.3.2 Meteorology model inputs

AERMOD requires representative meteorological data in order to accurately simulate air quality impacts. The applicant used surface meteorological data collected for a five

consecutive

- year period (2004

- 2008) at the Redding Municipal Airport meteorological

sta tion. This station is located approximately 2.8 (4.5 km) miles from the project site. The applicant processed these data using EPA’s AERMET data processor

. EPA concurs that the chosen 2004

- 2008 Redding data is the most representative for the SPI

- Anderson analysis.

For upper air data, the applicant obtained data from the 2004

- 2008 Medford

, Oregon upper air site located approximately 134 miles ( 215 km) northwest of the p roject site as being the most representative site available that had data comp lete enough to use. No other upper air meteorological monitoring stations are located closer to the project site. (Updated PSD Application,p.13pdf.17 ). EPA agrees that it is appropriate to use Medford, Oregon upper air data for the SPI

- Anderson analysis

.



### 8.3.3 Land characteristics model inputs

Land characteristics are used in the AERMOD modeling system in three ways: 1) via elevation within AERMOD to assess plume interaction with the ground; 2) via a choice of rural versus urban algorithm within AERMOD; and 3) via specific values of AERMET parameters that affect turbulence and dispersion, namely surface roughness length, Bowen ratio, and albedo. The surface roughness length is related to the height of obstacles to the wind flow and is an important factor in determining the magnitude of

mechanical turbulence. The Bowen ratio is an indicator of surface moisture. The albedo is the fraction of total incident solar radiation reflected by the surface back to space without absorption

.

Terrain elevations for re ceptors and emission sources were prepared using 1/3 rd arc

second National Elevation Dataset data developed by the United States Geological Survey (USGS), and available on the internet from the USGS Seamless Data Server (http://seamless.usgs.gov/index.php) . These data have a horizontal spatial resolution of approximately 10 meters . Terrain heights surrounding the facility indicate that some of30 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 the receptors used in the simulations were located in intermediate or complex terrain (above stack or plume height)

. For determining concentrations in elevated terrain, SPI

chose the AERMAP terrain preprocessor receptor

- output file option

.

SPI determined s urface parameters including the surface roughness leng th, albedo, and

Bowen ratio f

or the area surrounding the Re dding Municipal Airport meteorological tower using the AERMET preprocessor, AERSURFACE (Version 08009), and the USGS

1992 National Land Cover (NLCD92) land

- use data set. The NLCD92 data set used in the analysis has 30 m eter data point spacing and 21 land

- use categories. Seasonal surface parameters were determined using AERSURFACE according to EPA’s guidance

.

EPA requested additional detail characterizing the surface parameters surrounding the

SPI

- Anderson site for comparison with the airport site. Ba sed on this comparison, the applicant and EPA conclude that the use of Redding meteorological data is adequately representative of the p roject site.



### 8.3.4 Model receptors

Receptors in the model are geographic locations at which the model estimates

concen trations. The applicant places the receptors such that they have good area coverage and are closely spaced enough so that the maximum model concentrations can be found. At larger distances, spacing between receptors may be greater than it is close to the source, since concentrations vary less with increasing distance. The spatial extent of the receptors is limited by the applicable range of the model (roughly 50 km for AERMOD), and possibly by knowledge of the distance at which impacts fall to negligible levels. Receptors need be placed only in ambient air, that is, locations to which the public has access, and that are not inside the project fence line.

The applicant used Cartesian coordinate receptor grids to provide adequate spatial

coverage surroun ding the project are a and to identify the extent of significant impacts and

the maximum impact location. For all analyses except 1

- hour average NO 2 , receptors were spaced 500 m apart covering the 10 km square simulation domain, with 200 m, 50 m, and 25 m s pacing receptors grids covering 5 km, 2.5 km, and 1.25 km nested square areas centered on the facility, respectively. Receptors were also located at 25 m intervals along the facility property boundary. For the 1

- hour average NO 2 analysis, the modeling domain was extended to 20 km, and the additional area was covered by receptors placed 500 m apart. (Surface Characteristics, p.1pdf1)



### 8.3.5 S tack parameter model inputs

The modeling conducted by the applicant used the corresponding stack parameters in

Tab le 8.3

- 1 for normal operations and during startup and shutdown to provide

conservative estimates of SPI

- Anderson impacts

.31 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 8 .3

- 1 : Load S creening and S tack P arameters for Cogeneration Unit Operating

Mode Stack H eight

(ft) Stack Diameter

(ft) Stack Velocity

(ft/sec) Stack Temp erature

(°F)

SU/SD 85 8.5 36.7 294

Normal 85 8.5 61.1 350

Operating

Mode NO

x

(lb/hr) PM 10 / PM 2.5

(lb/hr) CO

(lb/hr)

SU/SD 70.2 8.93 432

Normal 70.2 8.93 108

Source for both parts of table 8

- 3 : Updated Air Dispersion Modeling Analysis (May 2012), p.3, Tables 1,2 and 5pdf.3, 7 and 10

.



### 8.3.6 Good Engineering P ractice (GEP) Analysis

The applicant performed a Good Engineering p ractice (GEP) stack height analysis to ensure that downwash is properly considered and that stack heights used as inputs to the modeling are no greater than GEP height . This disallow s artificial dispersion from the use of overly tall stacks. As is typical, the GEP analysis was performed with EPA’s Building

P rofile Input P rogram software, which u ses building dimensions and stack heights as inputs. Based on the analysis, the applicant shows that the GEP stack height for the boiler stack would have to exceed the maximum creditable GEP height of 65 m in order to ensure protection against downwash

. T he applicant showed that the GEP stack height for the other equipment was similarly greater than the planned heights. So, for all emitting units, the applicant used the planned actual stack heights for inputs in AERMOD modeling, and included wind directio n

- specific Equivalent Building Dimensions to properly account for do wnwash. (PSD Application p.14pdf.1 8)



### 8.4 National Ambient Air Quality Standards (NAAQS) and PSD Class II Increment Consumption Analysis

8.4.1 Pollutants with significant emissions

40 CFR § 52.21 requires an air quality impact analysis for each PSD

- regulated pollutant (for which there is a NAAQS) that a major source has the PTE in a significant amount,

i.e. , an amount greater than the Significant Emission Rate (SER) for the pollutant. Appl icable SPI

- Anderson emissions and the SERs are shown in Table 8 .4

- 1

. As shown

in Tabl e 8 .4

- 1 , EPA does not expect SPI

- Anderson to emit Pb , VOC and SO 2 in significant amounts. However, based on the estimates submitted by th e applicant, EPA

expects SPI

- Anderson to emit CO, NO

x , PM 10 , and PM 2.5 in significant amounts. Therefore, this project triggers the air impact analyses requirements for CO, NO 2 , PM 10 and PM 2.5

.32 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 8 .4

- 1 : PSD Applicability to SPI

- Anderson : SER

Pollutant Emissions

(tpy) S ER

(tpy) Does PSD

Apply ?

CO 47 2 100 Yes

NO

x 2 67 40 Yes

PM 10 42.1 15 Yes

PM 2.5 42.1 10 Yes

SO 2 10 .3 40 No

Pb 0.0 3 0.6 No

VOC 3 4.8 40 No



### 8.4.2 Preliminary analysis: P roject

- only impacts (Normal Operations and Startup)

EPA has established Significant Impact Levels (SILs) to characterize air quality impacts. A SIL is the ambient concentration resulting from the facility’s emissions, for a given pollutant and averaging period, below which the source is considered to have an insignificant impact. For maximum m odeled concentrations below the SIL, further air quality analysis for the pollutant is generally not necessary. In some cases it may be appropriate to consider additional information in order to conclude that a source will not be responsible for creating a new NAAQS exceedance, however. For maximum concentrations that exceed the SIL, EPA requires a cumulative modeling analysis

, which incorporates the combined impact of nearby sources of air pollution to determine compliance with the NAAQS and PSD incremen ts.

Table 8 .4

- 2 shows the results of the preliminary or p roject

- only analysis based on

maximum operations for SPI

- Anderson . Startup emissions are used for determinin g the

maximum 1

- hour NO 2 , 1

- hour and 8

- hour CO, and 24

- hour PM 10 , PM 2.5 impacts with maximum project impacts from normal operations included in paren theses. Startup CO emissions are expected to exceed those experienced during normal operating conditions. Startup and normal 1

- hour NO 2 and 24

- hour PM 10 , PM 2.5 emissions are the same; only th e flow rates are lower for the startup case. 1

- hour NO 2 impacts are based on the assumption that 80 % of the NO is converted to NO 2 , while the annual average NO 2 concentrations are based on the assumption that 75 % of the NO is converted to NO 2

. Based on Ta ble 8.4

- 2

, SPI

- Anderson ’s impacts are significant only for annual and 1

- hour

NO 2 , and 24

- hour PM 2.5 , and we have determined that in this case cumulative impacts analyses are required only for these pollutants and averaging periods.33 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 8 .4

- 2 : SPI

- Anderson Significant Impacts

NAAQS p ollutant,

A veraging T ime Project

- only

Modeled Impact ( μg/m 3 ) Significant

Impact Level ( μg/m 3 ) Significant

Impact ?

NO 2 , 1

- h ou r 38.6 (26.3) 7.5 (4 ppb) Yes

NO 2 , annual 1.35 1 Yes

PM 10 , 24

- h our 3 .36 (2.23) 5 No

PM 2.5 , 24

- h our 3.11 (1.84) 1.2 Yes

PM 2.5 , annual 0.2 7 0.3 No
CO, 1

- hour 307 (122) 2000 No
CO, 8

- hour 212 (36) 500 No

Sources : Updated Modeling Analysis (May 2012), Table s 3 and 6 pdf8,11



### 8.4.3 Cumulative impact analysis

A cumulative impact analysis considers impacts from nearby sources in addition to impacts from the p roject itself. F or demonstrating compliance with the NAAQS the applicant also adds a background concentration to represent those sources not explicitly included in the modeling, so that the tota l accounts for all contributions to current air quality . In this case, the applicant submitted cumulative impact analyses demonstrating compliance with the 24

- hour PM 2.5 NAAQS and the annual and 1

- hour NO 2 NAAQS.

PSD increments are limits on cumulative ai r quality degradation. They are set to prevent air with pollutant concentrations lower than the NAAQS from being degraded to the level of the NAAQS . P SD increments apply in addition to the NAAQS. Increments have been established for some pollutants, such as for this project, specifically for NO 2 , PM 10 and

PM 2.5

. For demonstrating compliance with the PSD increment, only increment

consuming sources need to be included because the increment concerns only changes occurring since the applicable baseline date.

T here is an annual NO 2 PSD increment, but there is no 1

- hour NO 2 PSD increment; therefore, only 24

- hour PM 2.5 and annual NO 2 require cumulative PSD increment analyses.

For evaluating NO 2 annual increment in this analysis, the applicant used all of the same sources that were in the NAAQS inventory, which is conservative.

With respect to the PSD increment analysis for PM 2.5 , the applicable trigger date when

the PM 2.5 increments become effective under the Federal PSD program is October 20,

2011. The S PI

- Anderson PSD permit application was determined to be administratively complete by EPA on October 4, 2010. However, EPA is requiring each source that receives its PSD permit after the trigger date, regardless of when the application was submitted, to p rovide a demonstration that the proposed emissions increase, along with other increment consuming emissions will not cause or contribute to a violation of the

PM 2.5 increments. Also the major source baseline, which precedes the trigger date is the

date aft er which actual emissions increases associated with construction at any major stationary source consume PSD increment. That date is October 20, 2010. With this PSD34 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 permit, SPI

- Anderson would begin construction after this date. In general, for PM 2.5 , the

mi nor source baseline date is the earliest date after the trigger date of a complete PSD permit application for a source with a proposed increase in emissions of PM 2.5 that is significant. No source has triggered the minor source baseline date in the area a t issu e. Other than SPI

- Anderson’s projected construction emissions, t here have been no actual emissions changes of PM 2.5 from any new or modified major stationary source on which construction commenced after October 20, 2010 . Therefore, the only source t o consume
PM 2.5 increment in the area is SPI

- Anderson. T he applicant considered only the

allowa ble emissions increase from the SPI

- Anderson project in the 24

- hour PM 2.5 increment analysis

.



### 8.4.3.1 Nearby source emission inventory

For both the PSD increment and NAAQS analyses, there may be a large number of sources that could potentially be included

. Only sources with a significant concentration gradient in the vicinity of the source need to be included; the number of such sources is expected to be small

, exce pt in unusual situations. (GAQM 8.2.3)

Shasta and Tehama Counties provided a list of all stationary sources w ithin their counties

and within 55.4 km of the project site (approximate distance to the farthest significant impact plus 50 km) for N O 2 and 51.0 km for PM 2.5

. A comprehensive procedure was used to determine which sources were included in the emissions inventory to be modeled. This included screening out a source by whether it had a significant impact where the project was predicted to h ave a significant impact

.

We note that short

- term maximum emission rates are used rather than annual emission

rates to determine the distance over which a facility might have a significant impact for

short

- term standards ( e.g. , hourly NO 2 ) . Use of short

- term rates results in the greatest impacts at the farthest distance

. Thus, the p eak rates that occur d uring startup determine

the SPI

- Anderson significant impact area (SIA) for hourly NO 2

.

SPI identified nine facilities nearby for inclusion in the emission inventory for the 1

- hour

NO 2 cumulative analysis, based on data from Shasta and Tehama Counties. The following non

- SPI

- Anderson facilities and their NO

x and PM 2.5 emissions are included in the cumulative compliance demonstration: Kiara Co Gen p roject, Wheelabrator Shasta

Co

- Gen (NO

x only), Wheelabrator Lassen Gas Turbine ( NO

x only), City of Redding

p ower p lant ( NO

x only), Ag P roducts Asphalt ( NO

x only), JF Shea Smith Road Asphalt, Lehigh Cement ( NO

x only), North State Asphalt ( NO

x only), and Te hama P rocessing ( NO

x only). These facilities are large enough and close enough to the p roject site to have the potential to directly impact the p roject’s SIA . ( Updated Air Dispersion Modeling Analysis , Tables 13

- 14pdf.20

- 21).

Current EPA NO 2 guidance recommends that emphasis on determining which nearby

sources to include in the nearby source inventory should focus on the area within about

10 km of the project location in most cases

. This indicates that the SPI

- Anderson inventory is adequate for perfor ming these cumulative analyses (p.16 of “Additional Clarification Regarding Application of Appendix W Modeling Guidance for the 1

- hour35 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 NO 2 National Ambient Air Quality Standard”, Memorandum from Tyler Fox, EPA Air Quality Modeling Group to EPA Regional Air Division Directors, March 1, 2011).

C onsider ing a focus on sources within 10 km

, EPA concludes that the combination of representative background monitored concentrations and the additional consideration of sources out to 50 km provide sufficient justif ication for the inventories used in the cumulative analysis.



### 8.4.3.2 Discussion of Certain PM 2.5 

### - Specific Considerations

EPA has issued guidance on how to combine modeled results with moni tored background

concentrations which the applicant adequately followed. (“Modeling p rocedures for Demonstrating Compliance with PM 2.5 NAAQS”, memorandum from Stephen D . P age, Director, EPA OAQPS, March 23, 2010.)

SPI provided a cumulative PM 2.5 24

- hour analysis. The applicant’s analysis conservatively assumed that all PM 10 emissions were comprised of PM 2.5 emissions, and

therefore used PM 10 emissions data as input to the modeling . Thus, actual PM 2.5 impacts

are expected to be lower than those indicated in the model results.

PM 2 .5 is either directly emitted from a source (primary emissions) or formed through chemical reactions with pollutants already in the atmosphere (secondary formation). EPA has not developed and recommended a near

- field model that includes the necessary

chem istry algorithms to estimate secondary impacts in an ambient air analysis.

The SPI

- Anderson application does not specifically address secondarily formed PM 2.5 (as distinguished from directly emitted primary PM 2.5 ). Secondary PM 2.5 is formed through t he emission of non

- particulates ( i.e. , gases)

– such as SO 2 and NO

x – that turn into fine particulates in the atmosphere through chemical reactions or condensation. Using the results for PM 2.5 impacts given in Tables 8 .4

- 2 and 8 .4

- 3 and the projected

emission rates of SO 2 , NO

x and PM 2.5 , EPA notes that the SPI

- Anderson emissions of

10 .3 tpy SO 2 are less than the SO 2 SER of 40 tpy , and would not be expected to result in significant secondary PM 2.5 . The SPI

- Anderson NO

x emissions of 2 67 tpy are above the

NO

x SER of 40 tpy . However, secondary PM 2.5 formation occurs only as a result of chemical transformations that would affect only a portion of those emissions . Moreover,

the formation occur s gradually over time as the plume travels an d becomes increasingly

diffuse and would be expected to be considerably smalle r than the impacts from the 42.1

tpy of directly emitted primary PM 2.5 . The maximum impact of source primary PM 2.5 was 3.11 μ g /m 3 for 24

- hour PM 2.5 and 0.27 μ g /m 3 for annual PM 2.5 . The 24

- hour PM 2.5 cumulative impacts anal ysis which gives a maximum impact of 28.8 ug/m 3

, with a background concentration of 15.3 ug/m 3 , in dicates that at least 6.2 μ g /m 3 remain s available for the 24

- hour averaging time before the NAAQS is challenge d (35 μ g /m 3

– 28.8 μ g /m 3 )

. For the annual averaging time no cumulative impact analysis was required because the project’s annual impacts were less than the SIL. However, the background

concentration was 5.3 μ g /m 3 . Adding this result to the project’s predicted impact of 0.27

μ g /m 3 yields a concentration of 5.57 μ g / m 3 . This result is less than a third of the NAAQS and leaves about 9 μ g /m 3 remaining before the NAAQS is challenged

. The36 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 monitored background PM 2.5 concentrations would also conservatively include secondarily formed PM 2.5 from the surrounding/nearby sources

. Because the secondary

PM 2.5 formation from SPI

- Anderson ’s NO

x emissions would be expected to be considerably smaller than the primary PM 2.5 impacts, they would also be smaller than the

additional 6. 2 μ g /m 3 or 9 μ g /m 3 needed to cause or contribute to a PM 2.5 NAAQS violation. In addition, most of these chemical transformations in the atmosphere occur slowly (over hours or even days, depending on atmospheric conditions a nd other variables), causing secondary PM 2.5 impacts to occur generally at some distance from the source of its gaseous emissions precursors, and are unlikely to overlap with nearby maximum primary PM 2.5 impacts.



### 8.4.3.3 Discussion of Certain 1

- hour NO 2 

### - Sp ecific Considerations

While the new 1

- hour NO 2 NAAQS is defined relative to ambient concentrations of NO 2 , the majority of NO

x emissions from stationary sources are in the form of nitric oxide (NO) rather than NO 2

. GAQM notes that the impact of an individual source on ambient

NO 2 depends in part “on the chemical environment into which the source’s plume is to be emitted” (see Section 5.1.j). Because of the role NO

x chemistry plays in determining ambient impact levels of NO 2 based on modeled NO

x emi ssions, Section 5.2.4 of GAQM

recommends a three

- tiered screening approach for NO 2 modeling. Later guidance documents issued by EPA expand on this approach. Tier 1 assumes full conversion of

NO to NO 2 . Tiers 2 and 3 are refinements of the amount of conv ersion of NO to NO 2

. The applicant used the Tier 2 approach, in which the 1

- hour NO 2 impacts are based on the assumption that 80 % of the NO is converted to NO 2 , while the annual average NO 2 concentrations are based on the assumption that 75 % of the NO is converted to NO 2.

A . NO 2 monitor representativeness/conservativeness

T he applicant chose the Manzanita Avenue monitor in Chico f or background NO 2

co ncentrations. This monitor is approximately 90 km from the SPI

- Anderson site and is

the closest NO 2 monitor to the project site. No other NO 2 monitor is located within 90

km of the site. Despite its distance from the project site, the monitor from Chico is

conservative based on its proximity to a more industrial area at the north end of the

Sacramento Valley.

B . Combining modeled and monitored values

SPI used one of the approaches in an EPA March 2011 memo which recommends using

the 98 th percentile of the annual distribution of daily maximum 1

- hour values averaged across the most recent three years of monitored data as a uniform background contribution to the modeled results. This procedure is based on a conservative assumption.

EPA believes that the applicant’s overall approach to the 1

- hour NO 2 analysis for the

SPI

- Anderson project , including the e mission inventory, background concentrations of

NO 2 and the method for combining model results with monitored values, is adequately

conservative.37 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 

### 8.4.3.4 Startup and S hutdown A nalyses

As stated in Section 8.3.5, the applicant estimated boiler NO

x emissions during star tup and shutdown to be the same as those during normal operations, but with lower flow

rates, thus the app licant also modeled for startup and shutdown . The stack parameters input into the model such as exit temperature and exhaust v el ocity were consistent with a flow rate equal to approximately 6 0% of that associated with a full load, and a reduced exhaust temperature of 250 ° F or 394 degrees K ( Updated Air Dispersion Modeling Analysis, May 2012). The startup period may last up to 24 hours from a “cold” (ambient temperature) furnace with the initial fire employing natural gas

- fired burners combusting pipeline natural gas. SPI

- Anderson anticipates only two planned cold startup and shutdown events during the year for maintenance.



### 8.4.3 .5 Results of the C umulative I mpacts A nalysis

The results of the PSD cumu lative impacts analysis for SPI

- Anderson ’s normal operations for PM 2.5 and startup emissions for 1

- h ou r NO 2 are shown in Table 8 .4

- 3 . The analysis demon strates that emissions from SP I

- Anderson will not cause or contribute to exceedances of the NAAQS for annual and 1

- hour NO 2 or 24

- hour PM 2.5 or for the

increments for annual NO 2 or 24

- hour PM 2.5 . The background concentrations were taken

from Table 8

. 2

- 1

.

EPA also considered additional information to ensure that the modification would not be responsible for causing a new NAAQS exceedance outside this modeling area. EPA considered sources in Shasta and Tehama Counties (no sources of interest were located

ou tside of these counties) that were not included, but which had been evaluated for inclusion/exclusion in the cumulative impacts modeling. EPA concluded that these sources are either small enough or distant enough that the p roject’s expected emissions along with emissions from these sources would not create any new NAAQS exceedance in the modeling area outside of the SIA.

Table 8 .4

- 3 : SPI

- Anderson Compliance with Class II PSD Increments and NAAQS

P ollutant

. A veraging

T ime All Sources

Modeled Impact Background

Concentration Cumulative

I mpact w/

B ackground NAAQS

(μ g/m 3 ) PSD

Increment Consumption PSD

Increment

NO 2 , 1

- h ou r 94 62.7 157 188 (100 ppb) NA NA

NO 2 , annual 1.75 33.1 34.8 100 (53) 1.75 25

PM 2.5 , 24

- h ou r 13.5 15.3 28.8 35 3.36 9

Notes:

- There are no PSD increments defined for 1

- hour NO 2

. Sources:

NO 2 , PM 2.5 (NAAQS): Updated Air Dispersion Modeling Analysis (May 2012) Table s 15 and 16 pdf22

- 23: PM 2.5 increment consumption less than all sources modeled impact due to non

- increment consuming fugitive source at

SPI

- Anderson being included in NAAQS analysis.38 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 

### 8.4.3.6 Impact on Ozone Levels

The re is a projected 267 tpy increase in NO

x emissions. Shasta County is an attainment

area for O 3 . There are four O 3 monitors located in the Redding area. The highest design value from these monitors is 71 ppb. The monitor with the highest value is located on the north side of Redding about 25 km f rom SPI

- Anderson. The NAAQS is exceeded if the design value is 75 ppb . As explained further below, there is no evidence in any recent O 3 regional modeling that an increase in 267 tpy of NO

x would result in a 4 ppb O 3 increase and threaten the NAAQS.

The emissions of VOC and NO

x that react to form O 3 come from a variety of local and regional anthropogenic and natural source categories. Anthropogenic VOC emissions are associated with evaporation and combustion processes, especially industrial processes

and transportation. Natural VOC emissions from vegetation are much larger than those from anthropogenic sources. Anthropogenic NO

x emissions are associated with combustion processes, especially mobile sources and electric power generation plants. Major natural sources of NO

x include lightning, soils, and wildfires. Given the large number of local and regional VOC and NO

x sources affecting O 3 concentrations in a given area, the impact of any single emission source is generally very small.

Furthermore, given th e complex nature of O 3 chemistry, the response of the O 3 system can be rather stiff in certain areas, meaning that it generally takes a substantial change in precursor emissions to produce a discernible change in O 3 concentrations on a single day.

For exam ple, modeling performed for the San Joaquin Valley 2007 O zone P lan for the Hanford site indicates changes in NO

x emissions over the entire air basin on the order of

20% may increase O 3 by approximately 6 % to 7%

. Another assessment tool used in the

San Joaquin Valley scaled the San Joaquin Valley 2007 Ozone P lan's Arvin 2023 Ozone Response Diagram to estimate the change in ozone per change in NO

x emissions. Using this information and scaling the 267 tpy of NO

x emissions from the proposed

modi fication would result in O 3 increases well below 1 ppb

.



### 8.5 Class I Area Analysis

8.5.1 Air Quality Related Values

The four nearest Class I areas are all within 100km of the p roject site and are listed

below :

Yolla Bolly

– Middle Eel Wilderness Area (57 km)

Thousand Lakes Wilderness ( 6 2 km)

Lassen National p ark (64 km)
Caribou Wilderness Area (89 km)

There are five additional areas within 200 km: Marble Mountain Wilderness Area (116 km), Redwood National P ark (147km), Lava Beds National Monument (148 km) and

South Warner Wilderness Area (192km).39 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Based on the mos t recent F ederal L and Managers’ A ir Quality Related Values (AQRV)

Work G roup (FLAG) (2010) published guidance

, the following screening approach is

used to determine whether a more refined Class I Air Quality Analysis is required. This approach only applies to projects located more than 50 km from a Class I area, and it requires adding all of the visibility

- related emissions (SO 2 , NO

x , PM 10 and sulfuric acid mist) from a project (based on 24

- hour ma ximum allowable emissions expressed in units

of t py )

, known as Q

, and dividing Q by the dista nce D between the project and Yolla Bolly, the nearest Class I area

. If the result ( Q / D ) is less than 10, the project is presumed to have negligible impacts to Class I AQRVs. Table 8 .5

- 1 shows that the p roject’s Q/D is 5.39, well below the FLAG screening criteria. Therefore, no further Class I AQRV analysis is required.

Table 8.5

- 1 Summary of Q/D Analysis

Project p arameter Value NOx Emissions Increase (tpy) 254 (1) SO2 Emissions Increase (tpy) 9.78 (2) PM10 Emissions Increase (tpy) 39.1 (3) H2SO4 Emissions Increase (tpy) 4.12 (4) Q = p roject Emissions Increase (tpy)

= (1) + (2) + (3)+ (4) 307

D= Distance to Closest Class I Area (km) 57

Q/D (tpy/km) 5.39 Q/D Threshold (tpy/km) 10



### 8.5.2 Class I Increment Consumption Analysis

EPA requires an analysis addressing Class I increment impacts for applicable pollutants

, regardless of the results of the Class I AQRV analysis. The analysis for annual NO 2 and

PM 10 and for PM 10 24

- hour was included in the original application submitted in 2007. Based on the results, EPA did not require updated modeling to be submitted with the

2010 PSD application because of the very low predicted impacts

. The applicant provided

a PM 2.5 Class I increment analysis in Updated Air Dispersion Modeling Analysis (May 2012) for Yolla Bolly, the closest Class I area, because this would provide the most

conservative results. The applicant used the original CALPUFF results from the Original

PSD Application (May 2007) and the CALPUFF post processing programs. To obtain

PM 2.5 concentrations, coarse PM , sulfate, and nitrate fractions were re moved from the

post

- processing originally used to develop PM 10 concentrations. The results are presented

in Table 8 .5

- 2

.

SPI’s application was complete on October 4, 2010. T here have been no changes in actual

emissions of PM 2.5 from any major stationary s ource on which construction commenced after October 20, 2010, the major source baseline date for PM 2.5 , for purposes of analyzing PM 2.5 increment consumption here. Also, n o source has triggered the minor

source bas eline date in the area at issue . Therefore , for purposes of this Class I PM 2.5 increment analysis, we consider only SPI

- Anderson’s increment consumption. Because40 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 SPI

- Anderson’s impacts are much less than the Class I SILs, and the Class I SILs are much lower than the increments, SPI

- Anderson’s maximum impacts are well below the

PM 2.5 increments. Therefore, the applicant has demonstrated that the project will not cause or contribute to any Class I PSD increment violation fo r PM 2.5 . Additionally, NO 2 and PM 10 impacts are well below their respective significant impact levels; therefore, the applicant has demonstrated the project will not cause or contribute to any Class I

violation for PM 10 or NO 2

.

Table 8 .5

- 2 : SPI

- Anderson C lass I Increment Impacts at Two Closest Class I Areas

Class I Area Pollutant,

A veraging T ime Project Impact

( μg/m 3 ) Significant

Impact Level ( μg/m 3 ) Class I PSD

Increment, ( μg/m 3 )

Yolla Bolly

Middle Eel

Wilderness NO 2 , annual 0.0006 0.1 2.5

PM 2.5 , 24

- h ou r 0.012 0.07 2

PM 2.5 , annual 0.0006 0.06 1

PM 10 , 24

- h our 0.06 0.3 8

PM 10 , annual 0.002 0.2 4

Thousand Lakes

Wilderness NO 2 , annual 0.0009 0.1 2.5

PM 10 , 24

- h our 0.018 0.3 8

PM 10 , annual 0.001 0.2 4

Source : For NO 2 and PM 10 impacts: Original PSD Application, Table 5

- 3 pdf.48. For PM 2.5 impacts: Updated Air Dispersion Modeling Analysis, p.6pdf.6.



## 9

. Additional Impact A nalysis

In addition to assessing the ambient air quality impacts expected from a proposed new source, the PSD regulations require that EPA evaluate other potential impacts on 1) soils and vegetation; 2) growth; and 3) visibility impairment

. 40 CFR § 52.21(o)

. T he depth of the analysis generally depends on existing air quality, the quantity of emissions, and the

s ensitivity of local soils, vegetation, and visibility in the source's impact area.



### 9.1 Soils and Vegetation

The additional impact analysis includes consideration of potential impacts to soils and vegetation associated with the SPI

- Anderson emissions

. 40 CFR § 52.21(o)

. This component generally includes:

a screening analysis to determine if maximum modelled ground

- level concentrations of project pollutants could have an impact on plants; and a discussion of soils and vegetation that may be affected by proposed project emissions and the potential impacts on such soils and vegetation associated with

such emissions.

The proposed project will be within the physical footprint of disturbed land that is part of the existing facility operations of the SPI

- An derson sawmill parcel located in Shasta County, California. The applicant presented its discussion of potential impacts on soils41 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 and vegetation as part of its PSD application and supplemental application information (from 2007 through 2012 submittals) and its biological review information (from 2007 and 2010)

. This information is further discussed below regarding the modification ’s potential deposition on soils and the project’s model e d impacts compared to EPA’s screening concentrations and secondary NAAQS.

The potential impact on soils from air pollutants through deposition is presented in the 2007 application (Section 5.0) as part of the Class I AQRV analysis. Additionally, the applicant reviewed the U.S. Department of Agriculture Natural Resources Conse rvation Service’s Web Soil Survey 8 ; soils in the area had pH ratings of between 5.3 and 6.5. A current review of the same area indicates that the same soil types (primarily various types of loam with some cobbly alluvial areas) and pH (5.3 to 6.5) are pres ent. Then, as now, the modeled deposition fluxes of nitrogen and sulfur attributable to the project are unlikely to alter or influence the pH of soils in the area.

With respect to the April 2010 updated biological review, the applicant included an expand ed project study area beyond the original 2007 evaluation. Soil characteristics of the habitat of the federally listed plant species, the slender Orcutt grass, are described. Its general habitat includes vernal pools (and similar habitat), reservoir edges of stream floodplains, clay soils with seasonal inundation in valley grassland to coniferous forest or sagebrush scrub. Likewise, it is not expected that the project’s emissions will adversely affect the habitat of this species.

The applicant’s May 2012 a pplication supplement presents an updated air dispersion modeling analysis from its 2010 application update . P roject impacts are presented for normal project

- only (refer to May 2012, Table 3) and startup and shutdown project

- only (refer to May 2012, Table 6) modeling results. 9 The project’s SO 2 , NO 2 and CO concentrations were compared to EPA screening concentrations in EPA’s "Screening

p rocedure for the Impacts of Air p ollution Sources on p lants, Soils and Animals" (1980) 10

. The screening procedure is used as a tool to identify if the project could have an impact on plants, soils, and animals

. The project’s impacts do not exceed the screening concentrations for these pollutants. Table 9 .1

- 1 summarizes this information.

8 Web Soil Survey: http://websoilsurvey.nrcs.usda.gov

9 Tables 4 and 6 of the May 2012 correspondence were not relied upon because these tables refer to the State and local permit process, which rely on the State ambient air standards; Tables 3 and 5 are relevant for the federal PSD permit process.

10 “ Screen ing P rocedure for the Impacts of Air P ollution Sources on P lants, Soils, and Animals,” EPA 450/2

- 81

- 078,

December 1980

.42 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 9.1

- 1: P roject Maximum Concentr ations and EPA Guidance Levels

for Screening Concentrations for Ambient Exposures

Criteria p ollutant, Guidance Averaging

Time EPA Screening

Concentration (μg/m 3 ) Modeled Maximum

Concentrations (μg/m 3 ) Model

Averaging

T ime

SO 2 , 1

- Hour 917 1.67 1 hour

SO 2 , 3

- Hour s 786

(0.30 ppm) 1.55

(0.0006 ppm) 3 hour

SO 2 , Annual 18 0.07 Annual

NO 2 , 4

- Hour s 3,760 40.0 1 hour

NO 2 , 8

- Hour s 3,760 40.0 1 hour

NO 2 , 1

- Month 564 40,0 1 hour

NO 2 , Annual 94

(0.05 ppm) 1.35

(0.0007 ppm) Annual

CO

, Weekly 1,800,000 212 8 hour

The project’s impacts were also compared to the secondary NAAQS. For most types of soils and vegetation, ambient concentrations of criteria pollutants below the secondary NAAQS will not result in harmful effects because the secondary NAAQS are set to protect public welfare, including animals, plants, soils, and materials

. The modeled

maximum concentrations of SO 2 , NO 2 , PM 2.5 , and PM 10 are also significantly below the secondary NAAQS that have been established by EPA: 11

Table 9. 1

- 2 : P roject Maximum Con centrations and

Secondary NAAQS Standards

P ollutant

, Averaging Time Secondary NAAQS (μg/m 3 ) Modeled Maximum

Concentrations (μg/m 3 )

SO 2 , 3

- h our 1,300

(0.5 ppm) 1.55

(0.0006 ppm)

NO 2 , Annual 100

(0.053 ppm) 1.35

(0.0007 ppm)

PM 10 , 24

- hour 150 3.36

PM 2.5 , 24

- hour 35 3.11

PM 2.5 , Annual 15 0.27

In sum, based on our consideration of the information and analysis provided by the applicant, and other relevant information, we do not believe that emissions associated

with the p roject will generally result in adverse impacts to soils or vegetation

.

11 EPA has not promulgated a secondary NAAQS for CO.43 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 

### 9.2 Visibility Impairment

The additional impact analysis also evaluates the potential for visibility impairment ( e.g. , plume blight) associated with SPI

- Anderson

. 40 CFR § 52.21(o)

. Using procedures from

EPA’s Workbook for P lume Visual Impact Screening and Analysis 12

, the potential for visibility impairment is characterized for:

Class I areas located within 50 km of the proposed SPI

- Anderson modification;

and Class II areas identified as potentially sensitive state or federal parks, forests, monuments, or recreation areas.

There are no Federal Class I areas located within 50 k m of the p roject site; the nearest Class I area is Yolla Bolly

- Middle Eel (57 km away). The next nearest Class I area is

Thousand Lakes Wilderness Area (62 km away)

. For nearby Class II areas or recreation

areas, the applicant evaluated visibility impairment for the following within 50 km of the project site:

Sacramento River National Wildlife Refuge (NWR) 38.8 km at its closest point;

W hiskeytown National Recreation Area (NRA) 18.3 km at its closest point.

EPA has not yet established a quantitative visibility impairment threshold for Class II areas (similar to what exists for Class I areas). We requested that the applicant conduct a

Lev el 1 VISCREEN analysis, and

, if necessary

, a Level 2 screening analysis for these

two areas.

For Whiskeytown NRA and Sacramento River NWR , the impact of the p roject on visibility impairment, also known as plume blight, was assessed. The EPA VISCREEN screening model was used to estimate visibility impairment to these two areas from the project’s emissions. Effects of plume blight are assessed as changes in plume perceptibility ( Δ E) and plume contrast (C p ) for sky and terrain backgrounds. A Level 1

anal ysis, using default meteorological data and no site

- specific conditions, was conducted. Because the results of the Level 1 screening analyses indicated that some of the screening criteria were exceeded, a Level 2 analysis was conducted for both areas. A

de tailed discussion of the VISCREEN plume blight impact analysis is presented in the applicant’s Class II Area Visibility analysis submitted by the applicant to EPA in July

2012

.

The results of the Level 2 VISCREEN modelling runs are presented below in Tab les 9 .2

- 1, 9 .2

- 2, 9 .2

- 3 and 9 .2

- 4

. The VISCREEN results are presented for the two default worst case theta angles

– theta equal to 10 degrees representing the sun being in front of an observer, and theta equal to 140 degrees representing the sun being behi nd the observer

. A negative plume contrast means the plume has a darker contrast than the background sky.

12 “ Workbook for P lume Visual Impact S creening and Analysis (Revised)” , EPA, EPA

– 454 /R

– 92

– 023, 1992

.44 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Table 9 .2

- 1 : Whiskeytown NRA Class II VISCREEN

Model l ing Results of Changes in P lume P erceptibility ( Δ E)

Background Distance

( km ) Plume P erceptibility ( ΔE)

Theta 10 Theta 140 Criteria Sky 37.1 0.408 0.24 2.00

Terrain 37.1 0.911 0.187 2.00

Table 9 .2

- 2 : Whiskeytown NRA Class II VISCREEN Modeling Results of Changes in P lume Contrast (C p )

Background Distance

(km) Plume Contrast (C p )

Theta 10 Theta 140 Criteria Sky 37.1 0.005

- 0.003 0.05

Terrain 37.1 0.007 0.001 0.05

Table 9 .2

- 3 : Sacramento River NWR Class II VISCREEN

Mode l ling Results of Changes in P lume P erceptibility ( Δ E)

Background Distance

(km) Plume P erceptibility ( ΔE)

Theta 10 Theta 140 Criteria Sky 50.0 0.724 0.47 2.00

Terrain 38.9 1.209 0.104 2.00

Table 9 .2

- 4 : Sacramento River NWR Class II VISCREEN

Model l ing Results of Changes in P lume Contrast (C p )

Background Distance

(km) Plume Contrast (C p )

Theta 10 Theta 140 Criteria Sky 50.0 0.01

- 0.006 0.05

Terrain 38.9 0.008 0.001 0.05

The results from the VISCREEN model show that changes in plume perceptibility and plume contrast for sky and terrain backgrounds inside these two areas are below the

criteria thresholds. Therefore, the plume would not be perceptible against a sky or terrain background.

Consequently, EPA guidance indicates that these results may be used to determine that the project will not contribute to visibility impairment, and no further analysis is required.



### 9.3 Growth

The growth component of the additional impact analysis involves a discussion of general commercial, residential, industrial, and other growth associated with SPI

- Anders on. 40 CFR § 52.21(o). This analysis considers emissions generated by growth that will

occur in the area due to the modification

. In conducting this review, we focus on residential, commercial and industrial growth that is likely to occur to support the s ource under review including employment expected during construction and operations and45 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 potential growth impacts associated with this employment, this as impacts to local population and housing needs

EPA does not expect this project to result in any significant g rowth

. Construction of the proposed cogeneration unit would span between 14 and 18 months. Laydown and temporary worker parking areas will be located within the existing facility property boundary. During construction approximately 40 tempora ry workers would be added, however this demand would be mitigated by the use of existing employees.

Once the cogeneration unit is operational, the facility expects to employ approximately eight additional workers. The project will utilize existing roads a nd infrastructure , and n o additional roads or transportation infrastructure s are proposed for construction

. We do not expect the new cogeneration unit to ca u se significant growth in the area.



## 10

. Endangered S pecies

Pursuant to Section 7 of the Endangered Species Act (ESA), 16 U.S.C. 1536, and its implementing regulations at 50 CFR P art 402, EPA is required to ensure that any action authorized, funded, or carried out by EPA is not likely to jeopardize the continued existence of any endangered or threatened species or result in the destruction or adverse modification of such species ’ designated critical habitat

. EPA has determined that this

PSD permitting action is subject to ESA Section 7 requirements

.

The construction activities resulting from the proposed modification will occur on SPI

Anderson ’s existing facility footprint. All storm water runoff will be contained on the

site . P ower lines to be constructed between the new transformer and the existing switch yard will be strung overhead. It is anticipated that there will be three set s of suspended wooden poles to span the distance between the existing switch yard and the transformer to be located near the turbine building.

SPI has confirmed that construction activities will not occur wi thin 100 feet of the elderberry shrubs that are in the Pacific Gas and Electric power line Right of Way. The nearest construction activity to the existing elderberry plants will be the erection of the electrical power poles at the existing electrical sub

- s tation which are 137 feet away from the nearest elderberry shrub . The main construction area, where the boiler, turbine building, fuel shed, electrical substation cooling tower, and ESP will be built, is approximately 1,000 feet from the nearest elderberry shrub.

EPA concludes that the project will have no likely adverse effect on any endangered or threatened species or designated critical habitat. Discussions with the United States Fish and Wildlife Service support EPA’s conclusion.



## 1 1

. Environmental Justice Screening Analysis

Executive Order 12898, entitled “Federal Actions To Address Environmental Justice in46 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Minority p opulations and Low

- Income p opulations,” states in relevant part that “each Federal agency shall make achieving environmental justice part of its mission by identifying and addressing, as appropriate, disproportionately high and adverse human health or environmental effects of its programs, policies, and activities on minority populations and low

- income populations.” Section 1

- 101 of Exe c. Order 12898, 59 Fed. Reg. 7629 (Feb. 16, 1994).

This AAQIR concludes that the proposed modification will not cause or contribute to air quality levels in excess of health standards for the pollutants regulated under EPA’s proposed PSD permit for the proposed modification , and that the project will not result in disproportionately high and adverse human health or environmental effects with respect to these air pollutants on populations residing near the SPI

- Anderson site , or on the community as a who le.



## 1 2

. Clean Air Act Title V (O perating P ermit )

The SPI Anderson facility already must comply with a Title V O perating P ermit

, SCAQMD P ermit #94VP18c

. After the proposed cogeneration unit is constructed

, SCA Q MD P ermit #94VP18c will need to be revised to appropriately reflect the facility’s

current operations

. The SC AQMD has ju risdiction to issue the Title V Operating P ermit

for SPI

- Anderson

.



## 13

. Comment P eriod, P rocedures for Public Hearing
Requests, Final Decision, and EPA Contact

The comment period for EPA’s proposed PSD permit for the p roject begins on September 12 , 2012

. Pursuant to 40 CFR 124.12, EPA has discretion to hold a Public Hearing if we determine there is a significant amount of public interest in the proposed permit. Requests for a Publi c Hearing must state the nature of the issues proposed to be raised in the hearing. If a Public Hearing is to be held, a public notice stating the date, time and place of the hearing will be made at least 30 days prior to the hearing. Reasonable attempts will be made to notify directly any person who has commented on this proposal of any pending Public Hearing, provided contact information has been given to the EPA contact person listed below.

Any interested person may submit writte n comments or request a Public Hearing regarding EPA’s proposed PSD permit for this modification. All written comments and requests on EPA’s proposed action must be received by EPA via e

- mail by October 1 7

, 2012, or postmarked by October 1 7 , 2012

. Comments or requests must be sent or delivered in writing to Omer Shalev at one of the following addresses:

E

- mail: R9airpermits@epa.gov

U.S. Mail: Omer Shalev (AIR

- 3)

U.S. EPA Region 947 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 75 Hawthorne Street

San Francisco, CA 94105

- 3901 Phone: (415) 972

- 3538

Comments should address the proposed permit modification and facility, including such

matters as:
1. The Best Available Control Technology (BACT) determinations;

2. The effects, if any, on Class I areas;

3. The effect of the proposed facility on ambient ai r quality; and

4. The attainment and maintenance of the NAAQS.

All information submitted by the applicant is available as part of the administrative record. The proposed air permit, fact sheet/ambient air quality impact report, permit application and othe r supporting information are available on the EPA Region 9 website

at http://www.epa.gov/region09/air/permit/r9

- permits

- issued.html#pubcomment . The administrative record may also be viewed in person, Monday through Friday (excluding federal holidays) from 9:00 AM to 4:00 PM, at the EPA Region 9 address above. Due to building security procedures, please call Omer Shalev at (415) 972

- 3538 at least 24 hours in advance to arrange a visit. Hard copies of the administrative record can be mailed to individuals upo n request in accordance with Freedom of Information Act requirements as described on the EPA Region 9 website at http://www.epa.gov/region9/foia/

.

EPA’s proposed PSD permit for the proposed modification and t he accompanying fact sheet/ambient air quality impact report are also available for review at the Shasta County Air Quality Management District at 1855 Placer St., Suite 101 in Redding, CA 9600 1, and the Redding Public Library at 1100 Parkview Ave. in Redd ing, CA 96001

.

All comments that are received will be included in the public docket without change and will be available to the public, including any personal information provided, unless the comment includes Confidential Business Information (CBI) or oth er information whose disclosure is restricted by statute. Information that you consider CBI or otherwise protected should be clearly identified as such and should not be submitted through e

- mail. If you send e

- mail directly to the EPA, your e

- mail address will be automatically captured and included as part of the public comment. Please note that an e

- mail or postal address must be provided with your comments if you wish to receive direct notification of EPA’s final decision regarding the permit.

EPA will c onsider all written and oral comments submitted during the public comment period before taking final action on the PSD permit modification and will send notice of the final decision to each person who submitted comments and contact information during the p ublic comment period or requested notice of the final permit decision. EPA will respond to all substantive comments in a document accompanying EPA’s final permit decision.

EPA’s final permit decision will become effective 30 days after the service of not ice of

the decision unless:48 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 1. A later effective date is specified in the decision; or

2. The decision is appealed to EPA’s Environmental Appeals Board pursuant to 40
CFR Part 124.19; or

3. There are no comments requesting a change to the proposed permit decision, in which case the final decision shall become effective immediately upon issuance.

If EPA issues a final decision granting the PSD permit for this modification, and there is no appeal, construction of the modification may commence, subject to th e conditions of the PSD permit and other applicable permit and legal requirements.

If you have questions, please contact Omer Shalev at (415) 972

- 3538 or e

- mail at R9airpermits@epa.gov. If you would like to be added to our mailing list to receive future

i nformation about this proposed permit decision or other PSD permit decisions issued by EPA Region 9, please contact Omer Shalev at (415) 972

- 3538 or send an e

- mail to R9airpermits@epa.gov, or visit EPA Region 9's website at http://www.epa.gov/region09/air/ permit/psd

- public

- guidelines.html

.



## 1 4

. Conclusion a nd P roposed A ction

EPA is pro posing to modify the PSD permit for SPI

- Anderson facility owned and operated by SPI

. We believe that the proposed project will comply with PSD requirements including the install ation and operation of BACT, and will not cause or contribute to a violation of the NAAQS, or of any PSD increment

. We have made this

determination b ased on the information supplied by the applicant and our review of the analyses contained in the pe rmit application

. EPA will prov ide the proposed permit and this AAQIR to the public for review, and make a final decision after considering any public comments on our proposal

.49 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 

## Appendix A

- Greenhouse Gas Emissions Estimates

Discussion: EPA’s Deferral for CO 2 emissions from Bioenergy and Other Biogenic

Sources under the Prevention of Significant Deterioration and Title V p rograms (76 FR 43490 July 20, 2011) applies to this modification . Therefore, the determination of PSD applicability for GHG will exc lude CO 2 emissions from the burning of biomass fuel for

this proposed modification. The boiler is allowed to burn natural gas during startup and shutdown, but the proposed PSD permit limits the annual heat input from natural gas to

not exceed 10% of total heat input on an annual basis. Assuming 8,760 hours of operation

per year, t he total maximum non

- deferred emissions of GHG from this boiler are: i

Total Boiler CO 2 e without CO 2 from biomass

= 2,741 (from CH 4 ) + 5, 310 (from N 2 O) + 30,201 (from Natural Gas CO 2 )

= 38,252 CO 2 e50 of 50

SPI

- Anderson ( SAC 12

- 0 1 ) A mbient Air Quality Impact Report September 2012 Total Emergency Engine CO 2 e from Natural Gas

= 127 CO 2 e

Total Project CO 2 e

= Boiler CO2e + Emergency Engine CO2e

= 38,252 CO 2 e +127 CO 2 e

= 38, 379 CO 2 e

As calculated above, total annual CO 2 e emissions excluding CO 2 are 38, 379 tpy of CO 2 e
, which is below the GHG “subject to regulation” threshold of 75,000 tpy. As a result, the

modification is not subject to BACT requirements for GHG. ii

i The kg/MMBtu emission factors for combustion of wood and wood residual solid biomass fuel, as well as natural gas, are from 40 CFR Part 98, Tables C

- 1 and C

- 2; 1kg= 2.2046 lb

ii The emergency engine is limited to 100 hours of nonemerg ency use per year. The table conservatively assumes 500 hours of use per year.