Comparison of the Most Recent BACT/LAER 

Determinations for Combustion Turbines by State Air 

Pollution Control Agencies 

Paper #: 42752 

AWMA Meeting June 2002 

Prepared by Nishat H. Hydari, Adeel A. Yousuf and Dr. Howard M. Ellis, QEP 

Enviroplan Consulting, 81 Two Bridges Road, Fairfield, NJ 07004 

ABSTRACT 

A survey was conducted of state air pollution control agencies to determine the most 

recent Best Available Control Technology (BACT) and Lowest Achievable Emission 

Rate (LAER) determinations for natural gas combustion turbines used in electric power 

generation facilities. BACT and LAER for both simple cycle and combined cycle modes 

of turbine operation were evaluated. 

Any new major stationary source or major modification locating in an area attaining the 

National Ambient Air Quality Standard (NAAQS) is subject to Prevention of Significant 

Deterioration (PSD) requirements and must conduct an analysis to ensure the application 

of BACT. Also, any new major stationary source or major modification locating in an 

area not attaining the NAAQS is subject to non-attainment new source review permitting 

requirements and must conduct an analysis to ensure the application of LAER. 

Air pollution permitting agency decisions on BACT/LAER determinations weigh heavily 

on the most recent BACT/LAER determinations. This most recent data is not always 

readily available in the US EPA BACT/LAER Clearinghouse. This often results in a 

delay as applicants and state agencies search for the most recent BACT/LAER 

determinations. 

This paper is intended to address the need for current BACT/LAER determinations used 

by the state air pollution agencies and private industries. 

The study involved a survey of 28 state air pollution agencies in the eastern half of the 

United States. Each state was queried on the most recent BACT/LAER analysis for 

simple and combined cycle combustion turbines; compliance averaging time applicable 

to these determinations; different types of control technologies required by each state 

agency; the cost per ton of pollutant removed threshold for economic feasibility; and the 

total number of BACT/LAER determinations made by each state during the last 12 

months for this source group. This investigation primarily focused on the following 

pollutants: PM10, NOx, CO, SO2 and hydrocarbons. 
The data obtained from this study was statistically analyzed to prepare tables showing 

comparative analyses between states. Conclusions on regional differences between the 

states were made based on the BACT/LAER determinations obtained. 

INTRODUCTION 

Any new major stationary source or major modification locating in an area attaining the 

National Ambient Air Quality Standard (NAAQS) is subject to Prevention of Significant 

Deterioration (PSD) requirements and must conduct an analysis to ensure the application 

of BACT. Also, any new major stationary source or major modification locating in an 

area not attaining the NAAQS is subject to non-attainment new source review permitting 

requirements and must conduct an analysis to ensure the application of LAER. 

The regulatory decisions on BACT and LAER can have significant economic impacts on 

a proposed project (e.g. emission limits, allowable operating conditions). Thus, at the 

time of project development and the decision to proceed with the project, it is important 

to have timely information on the BACT and LAER determinations that will actually 

apply to the project. 

To provide a central clearinghouse for BACT, LAER and Reasonably Available Control 

Technology (RACT) determinations throughout the nation; U.S. EPA has established the 

RACT/BACT/LAER Clearinghouse. As described on its web page, “the 

RACT/BACT/LAER Clearinghouse (RBLC) database contains information distilled from 

early notification submittals and air permits received from State and local air pollution 

control programs in the United States. The RBLC Web site also contains summary 

information on air pollution emission standards. The data assists State/local agency 

personnel and private companies in determining what types of controls and pollution 

prevention measures have been applied to and/or are required for various sources and the 

effectiveness of these technologies.” (1) 

The challenge is that early in the planning process for a new project, the project 

developer needs access to the most recent BACT/LAER determinations to make 

decisions on project design and to fully evaluate the economic feasibility of the project. 

The time between the state or local regulatory decision on a BACT/LAER determination 

and the inclusion of that decision in the RBLC varies by state and can be substantial. 

The purpose of this paper is to present the results of a survey conducted of recent 

BACT/LAER determinations in states in the eastern half of the U.S. for a major source 

category - - new large combustion turbines form power generation. We compare these 

determinations state by state and see whether these determinations are, in fact, included 

in the RBLC database. 
SURVEY PROCEDURES 

The survey questions are given in Table 1. Questions addressed included date of permit 

issuance, combustion turbine type and size, pollutants for which BACT or LAER 

determinations were made and the determination for each pollutant, compliance 

averaging time in the determination, required control technology and the cost per ton of 

pollutant removed threshold for economic feasibility in the determination. 

Table 1. Survey questions 

Questionnaire on State Agency Experience in BACT and LAER Determinations for 

Three Most Recent Large Combustion Turbines Permitted 

State: Person Providing Response: 

Date: Email: Phone #: 

 Permit #1 Permit #2 Permit #3 

Permit # 

Date Permit Issued 

Combustion Turbine Type: 

(Combined Cycle (CC), Simple 

Cycle (SC)) 

 

Size: (Megawatts (MW) 

output(a) , MMBTU/hour fuel 

input) 

 

Pollutant: (NOx, CO, SO2, 

PM10, HC) 

 

Type of Determination: (BACT, 

LAER) 

 

Emission Standard: (ppm, 

lbs/MMBTU, % sulfur fuel, 

etc.) 

 

Compliance Averaging Time: (1 

hour, rolling 4-hour, etc.) 

 

Required Control Technology: 

(SCR and/or LNB for NOx, 

catalytic oxidation for CO, etc.) 

 

Cost per ton of pollutant 

removed threshold for economic 

feasibility in the determination 

(dollars/ton) 

 

Note: (a) MW output for combined cycle combustion turbines is upstream of the HRSG. 
Table 2 lists the 28 states contacted in this survey and those states that responded. In each 

state, we sought to contact the person in charge of the control technology determinations 

in the new source review process. Surveys were sent by e-mail with phone call follow up 

as needed. 10 of the 28 states provided survey responses that were sufficiently complete 

to include in the results. A total of 75 BACT determinations and 16 LAER 

determinations are included in the survey results. 

Table 2. States contacted in survey. 

State Status State Status 

Alabama Complete Mississippi Pending 

Arkansas Complete New Hampshire Complete 

Connecticut Complete New Jersey Pending 

Delaware Complete New York Complete 

Florida Complete North Carolina Pending 

Georgia Pending Ohio Pending 

Illinois Pending Pennsylvania Complete 

Indiana Complete Rhode Island Pending 

Kentucky Pending South Carolina Pending 

Louisiana Pending Tennessee Pending 

Maine Pending Vermont Pending 

Maryland Pending Virginia Pending 

Massachusetts Pending West Virginia Pending 

Michigan Complete Wisconsin Pending 

RESULTS 

Survey results are presented in the following five tables. 

Table 3 presents the average BACT determination by state for simple cycle, combined 

cycle and all combustion turbines for up to five air pollutants. Based on natural gas firing, 

for NOx, these average BACT determinations vary from a low of 3.5 to 7.67 ppm. For 

CO they vary from 7.67 to 22.5 ppm. For SO2, they vary from 0.00145 to 0.0055 

lbs/MMBTU, for PM10 they vary from 0.0059 to 0.021 lbs/MMBTU and for HC they 

vary from 2.2 to 6.7 ppm. 

Table 4 presents the average LAER determination by state for simple cycle, combined 

cycle and all combustion turbines for up to five air pollutants. Based on natural gas firing, 

for NOx, these average LAER determinations vary from 2.0 to 3.0 ppm. For CO the 

determination is 3.0 ppm. For PM10 the determination is 0.0155 lb/MMBtu and for HC 

they vary from 1.3 to 1.56 ppm. 
Table 5 presents the compliance averaging times included in the BACT and LAER 

determinations. Based on natural gas firing, for NOx, these compliance averaging times 

vary from one-hour never to be exceeded to four-hour rolling averages never to be 

exceeded. For CO they vary from one hour to 24 hour rolling never to be exceeded. For 

SO2, they vary from one hour to 3 hour never to be exceeded. For PM10, they vary from 

1 hour to 24 hour rolling and for HC they vary from one hour to 24 hour rolling. 
Table 3. The average BACT determination by state for simple cycle, combined cycle and 

all combustion turbines. 

State Pollutant Average BACT Determination 

 Simple Cycle 

Combustion Turbine 

Combined Cycle 

Combustion Turbine 

All Combustion 

Turbines 

 # Avg. BACT # Avg. BACT # Avg. BACT 

Alabama NOx 3 5.0 ppm 3 5.0 ppm 

 CO 3 12.0 ppm 3 12.0 ppm 

 PM10 3 0.0059 

lb/mmBtu 

3 0.0059 

lb/mmBtu 

 VOC 3 3.2 ppm 3 3.2 ppm 

Arkansas NOx 3 3.5 ppm 3 3.5 ppm 

 CO 2 22.5 ppm 2 22.5 ppm 

 PM10 1 0.013 

lb/mmBtu 

1 0.013 

lb/mmBtu 

 VOC 2 6.7 ppmv 2 6.7 ppmv 

Connecticut SO2 1 .005 lb/mmBtu 1 .005 lb/mmBtu 

 PM10 1 0.011 

lb/mmBtu 

1 0.011 

lb/mmBtu 

Delaware NOx 1 9 ppm 1 3 ppm 2 6 ppm 

 CO 1 9 ppm 1 9 ppm 2 9 ppm 

 SO2 1 0.003 

lb/mmBtu 

1 0.003 

lb/mmBtu 

2 0.003 

lb/mmBtu 

 PM10 1 0.02 lb/mmBtu 1 0.021 

lb/mmBtu 

2 0.0205 

lb/mmBtu 

Florida NOx 1 9 ppm 2 3 ppm 3 6 ppm 

 CO 1 9 ppm 2 8.5 ppm 3 8.75 ppm 

 SO2 1 0.0056 

lb/mmBtu 

1 0.0052 

lb/mmBtu 

2 0.0054 

lb/mmBtu 

 VOC 1 2.2 ppm 1 2.2 ppm 

Indiana NOx 1 9 ppm 2 3.0 ppm 3 6.0 ppm 

 CO 1 25 ppm 2 10.6 ppm 3 17.8 ppm 

 SO2 1 0.0052 

lb/mmBtu 

2 0.0058 

lb/mmBtu 

3 0.0055 

lb/mmBtu 

 PM10 1 0.0095 

lb/mmBtu 

2 0.0125 

lb/mmBtu 

3 0.011 

lb/mmBtu 

Michigan NOx 2 12 ppm 3 3.33 ppm 5 7.67 ppm 

 CO 1 25 ppm 3 5.57 ppm 4 15.29 ppm 

 VOC 3 6.47 ppm 3 6.47 ppm 

New 

Hampshire 

CO 2 15 ppm 2 15 ppm 

 SO2 2 0.00145 

lb/mmBtu 

2 0.00145 

lb/mmBtu 

 PM10 2 0.0095 

lb/mmBtu 

2 0.0095 

lb/mmBtu 

New York SO2 2 0.0038 

lb/mmBtu 

2 0.0038 

lb/mmBtu 

 PM10 1 0.021 

lb/mmBtu 

1 0.021 

lb/mmBtu 

Pennsylvania CO 3 7.67 ppm 3 7.67 ppm 
Table 4. The average LAER determination by state for simple cycle, combined cycle and 

all combustion turbines. 

State Pollutant Average BACT Determination 

 Simple Cycle 

Combustion Turbine 

Combined Cycle 

Combustion Turbine 

All Combustion 

Turbines 

 # Avg. LAER # Avg. LAER # Avg. LAER 

Connecticut NOx 1 2.0 ppm 1 2.0 ppm 

New 

Hampshire 

NOx 2 2.5 ppm 2 2.5 ppm 

New York NOx 2 2 ppm 2 2 ppm 

 CO 2 2 ppm 2 2 ppm 

 PM10 1 0.0155 

lb/mmBtu 

1 0.0155 

lb/mmBtu 

 VOC 2 1.3 ppm 2 1.3 ppm 

Pennsylvania NOx 3 3 ppm 3 3 ppm 

 VOC 3 1.56 ppm 3 1.56 ppm 
Table 5. Comparison of compliance averaging times in BACT/LAER determinations. 

State Pollutant Compliance Averaging Times Used in BACT/LAER Determinations 

Alabama NOx 3 hour 

 CO 3 hour 

Arkansas NOx 24 hour; 3 hour 

 CO 24 hour 

 PM10 3 hour 

 VOC 3 hour 

Connecticut NOx 3 hour 

 CO 1 hour 

 SO2 3 hour 

Delaware NOx 1 hour 

 CO 1 hour 

 SO2 1 hour 

 PM10 1 hour 

Florida NOx 24 hour block; 3 hour 

 CO 24 hour block 

 VOC 3 hour 

Indiana NOx 24 hour operating; 3 hour block 

 CO 24 hour 

Michigan NOx Day; 24 hour rolling; 3 hour 

 CO 24 hour rolling; day 

 PM10 Day; 24 hour rolling 

 VOC 24 hour rolling 

New 

Hampshire 

NOx 3 hour block average 

 CO 1 hour block average 

 SO2 3 hour rolling 

 PM10 1 hour block average 

New York NOx 3 hour rolling average 

 CO 1 hour average 

 SO2 1 hour; continuous 

 PM10 1 hour; 1 hour average 

 VOC 1 hour; 1 hour average 

Pennsylvania NOx 1 hour average 

 CO 1 hour average 

 SO2 1 hour average 

 PM10 1 hour average 

 VOC 1 hour average 
Table 6 presents the required control technologies in the BACT/LAER determinations. 

Table 7 presents the average cost per ton of pollutant removed threshold for economic 

feasibility in the BACT determination and in the LAER determination separately by state. 

The average cost per ton varies significantly by pollutant and among states. 

Finally, Table 8 provides an indication of how up to date the RLBC Clearinghouse data 

is. For each state, we show how many of the three most recent BACT/LAER 

determinations are in the RLBC Clearinghouse data. Overall, 14% of the most recent 

BACT/LAER determinations in this survey were in the RLBC Clearinghouse. 

CONCLUSIONS 

BACT and LAER determinations for large combustion turbines vary significantly by 

state. Similarly, the compliance averaging times also vary significantly. However, both 

the control technologies selected for BACT and LAER and the average cost per ton of 

pollutant removed threshold for economic feasibility are more consistent among the 

states. 

Finally, only 14% of the most recent BACT/LAER determinations in this survey were 

included in the RLBC database. U.S. EPA could help states make better BACT and 

LAER determinations by speeding up the process of incorporating the most recent BACT 

and LAER determinations in the RLBC database. 

REFERENCES 

(1) 40 CFR §52.21, Prevention of Significant Deterioration of Air Quality. 

(2) 40 CFR Part 51, Appendix S, Emission Offset Interpretive Ruling. 

(3) U.S. EPA web page. http://www.epa.gov/ttncatc1/rblc/htm/bl02.cfm 

KEY WORDS 

Combustion Turbines 

PSD 

BACT 

LAER 

RACT/BACT/LAER Clearinghouse
Table 6. Required control technologies in the BACT/LAER determinations. 

State Pollutant Required Control Technologies in the BACT/LAER Determinations 

Alabama NOx Dry Low NOx; SCR 

 CO Good Combustion 

 PM10 Good Combustion 

 VOC Good Combustion 

Arkansas NOx Dry Low NOx w/SCR 

 CO Catalytic Oxidation 

 SO2 Fuel Sulfur limitation 

 VOC Catalytic Oxidation 

Connecticut NOx SCR 

 CO Catalytic Oxidation 

Delaware NOx SCR 

 CO Fuel Sulfur limitation 

Florida NOx Dry Low NOx; SCR; SONOx 

 CO Combustion control; Catalytic Oxidation 

 SO2 Low sulfur fuels 

Indiana NOx Dry Low NOx Combustors; SCR 

 CO Good design/operation 

 SO2 Low sulfur fuel 

 PM10 Good combustion 

 VOC Good combustion 

Michigan NOx DLNB, SCR, Catalytic Oxidation 

 CO DLNB, SCR, Catalytic Oxidation 

 PM10 DLNB, SCR, Catalytic Oxidation 

 VOC DLNB, SCR, Catalytic Oxidation 

New Hampshire NOx LNB with SCR 

 CO Low NOx burner with good combustion practices 

 SO2 Low sulfur fuels, < 0.05% sulfur 

 PM10 Low sulfur fuels 

New York NOx SCR, LNB 

 CO Catalytic Oxidation 

 SO2 Low sulfur fuel 

 PM10 Fire only natural gas 

 VOC Catalytic Oxidation 

Pennsylvania NOx DLNC + SCR 

 CO + 

VOC 

DLNC, Oxidation Catalyst 

 SO2 Low sulfur fuel 

 PM10 NG 
Table 7. Average cost per ton of pollutant removed threshold for economic feasibility in 

the BACT/LAER determination. 

State Pollutant BACT Determinations Average Cost 

per Ton 

LAER Determinations Average Cost 

per Ton 

Arkansas CO/VOC 3,373 

 NOx 5,108 

Connecticut NOx 9,000 

Florida NOx 2,606 

Michigan NOx $22,000 

 CO $4,944 

 PM10 $85,000 
Table 8. BACT/LAER determinations from this survey that are in U.S. EPA’s 

RACT/LAER/BACT Clearinghouse Database 

State Pollutant BACT /LAER 

Determination

s in This 

Survey 

BACT/LAER 

Determinations from Survey 

that are in U.S. EPA’s 

RACT/LAER/BACT 

Clearinghouse Database 

Percentage of BACT/LAER 

Determinations from Survey that 

are in U.S. EPA’s 

RACT/LAER/BACT 

Clearinghouse Database 

Alabama NOx 3 0 0 

 CO 3 0 0 

 PM10 3 0 0 

 VOC 3 0 0 

Arkansas NOx 3 2 66.6 

 CO 3 2 66.6 

 PM10 3 2 66.6 

 VOC 3 2 66.6 

Connecticut NOx 1 1 100 

 SO2 1 1 100 

 PM10 1 1 100 

Delaware NOx 2 0 0 

 CO 2 0 0 

 SO2 2 0 0 

 VOC 2 0 0 

Florida NOx 3 0 0 

 CO 3 0 0 

 SO2 2 0 0 

 VOC 1 0 0 

Indiana NOx 3 1 33.3 

 CO 3 1 33.3 

 SO2 3 1 33.3 

 VOC 3 1 33.3 

Michigan NOx 5 0 0 

 CO 5 0 0 

 PM10 5 0 0 

 VOC 5 0 0 

New 

Hampshire 

NOx 2 0 0 

 CO 2 0 0 

 SO2 2 0 0 

 PM10 2 0 0 

New York NOx 2 0 0 

 CO 2 0 0 

 SO2 2 0 0 

 PM10 2 0 0 

 VOC 2 0 0 

Pennsylvania NOx 3 0 0 

 CO 3 0 0 

 SO2 3 0 0 

 PM10 3 0 0 

 VOC 3 0 0