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OAR Box 1781 

Prepped by Ollie Stewart 

Document Number: 

30) 11-1-22 

Docket Number: 

A-90-37 

Printed 10/29/2008 10:46:19 AM Sheet 30 of 142 
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4 » /?-9t-37 

n> ^251995 

NESCAUM BACT GUIDELINE 

October 1988 

Committee Draft - March 1991 

revisions are noted in italics 

i, INTRODUCTION 

The Northeast States for Coordinated Air Use Management (NESCAUM) is an 

interstate association of the air quality divisions in the Northeast states: Connecticut, Maine, 

Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, and Vermont. 

NESCAUM's purpose is to promote cooperation and coordination of technical and policy 

issues among its member states. To accomplish this, NESCAUM sponsors frequent air 

quality training programs, participates in national debates, and promotes a variety of 

research initiatives. 

Each of die NESCAUM states adroinisters programs for the preconstruction review 

of new sources and modifications of existing sources. Some states administer a delegated 

version of the Federal Prevention of Significant Deterioration (PSD) regulations while 

others have developed their own regulations which, upon approval by the U.S. 

Environmental Protection Agency (EPA), provide the state the authority to issue federally 

enforceable permits. The minimum size of sources subject to review varies from state to 

state, but all states require that sources review available control technologies and that the 

source select the Best Available Control Technology (BACT). For new major sources or 

major modifications in nonattainment areas, the control technology required is Lowest 

Achievable Emission Rate (LAER). 

The original policy was adopted by the NESCAUM Board of Directors at their 

meeting on October 11,1988. Revisions to the policy were reviewed and approved by the 

Directors on —, 1991. This policy does not change regulations in any state or any existing 

PSD requirement for a top-down BACT analysis. Rather, it is intended to promote 

consistency between member states in methods of determining BACT and to provide 

prospective applicants with guidance on the level of analysis appropriate to support a 

proposed control technology. This policy defines a top-down analysis as identifying the 

most stringent control available for a similar or identical source or source category. 

Working from that "top" case, the applicant begins the BACT analysis. 

H, BACKGROUND 

In the 1977 Amendments to the Clean Air Act, Congress adopted the Federal 

Prevention of Significant Deterioration Program. The program was designed to prevent air 

quality from deteriorating in areas where it was already better than the national ambient air 

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quality standards. This objective was approached in two ways. First, the program 

established increments to limit the amount of additional sulfur dioxide and particulate matter 

allowed to be emitted above the baseline (which is existing air quality). Second, the 

program required that, regardless of existing air quality, new emission sources subject to 

PSD would be controlled to a level that represents BACT. This requirement not only 

precludes potential applicants from shopping for areas with less stringent emission 

limitations, but also promotes the research and development of more efficient and more 

economic alternative technologies. 

EPA adopted regulations to implement the requirements of the 1977 Clean Air Act 

Amendments. These regulations were challenged by both industry and environmental 

organizations. In December 1979, in the case of Alabama Power et al., vs. Costle (13 

ERC 1225), the Washington, D.C. Circuit Court upheld some provisions while 

overturning others. Subsequendy, EPA promulgated changes to the regulatory 

requirements for new source review in amendments to Tide 40 of the Code of Federal 

Regulations on August 7,1980. On October 17,1988, EPA promulgated a final rule 

which adopted PSD increments for nitrogen oxides. As of March 1991, these provisions 

constitute the regulatory requirements for the review of new sources and major 

modifications of existing sources that all programs must meet These provisions may be 

changed as a result of the Clean Air Act Amendments of 1990. 

m. PURPOSE 

The purpose of this document is to promote consistent analysis of proposed control 

technologies and consistent procedures for reviewing BACT determinations from state to 

state. Establishing a uniform set of requirements will not only ensure equitable treatment 

for prospective applicants, but will also reduce pressure on reviewing agencies resulting 

from the argument that a similar source located elsewhere would not be subjected to the 

same requirements. It is also intended to provide prospective applicants with guidance on 

the BACT analysis process. Additional guidance may be obtained from EPA's draft New 

Source Review Workshop Manual (October 1990). 

The U.S. EPA requires top-down BACT analysis. This guideline states that the 

NESCAUM states will use a top-down BACT analysis. This approach is based on 

identifying the best technology solution, allowing for environmental, energy, and economic 

considerations. 

This guideline focuses on the type of data required in a preconstruction permitting 

application and how the data should be used in order to determine BACT. The guideline 

addresses how the emission control system proposed in the permitting application is 

determined to be BACT or why a more stringent level of emission control might be 

appropriate, considering available technology and economic, energy, and environmental 

factors. 

The Clean Air Act places the responsibility for proposing BACT with the applicant 

and the responsibility of deteimining BACT with the permitting agency. The top-down 

approach places the additional responsibility on the source to present and defend its 

proposal. 

The level of analysis (or documentation) to support a BACT deteiminatioh should 

be consistent from area to area. Since BACT is a case-by-case process, consistency does 

not necessarily mean that a new facility in one area will have an emission limit identical to 

that of the same type of facility in another area. Using a consistent approach to determine 

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BACT should ensure that the impacts of alternative emission control systems are measured 

by the same set of parameters. 

IV. APPLICABILITY 

The applicability criteria for imposition of the BACT requirement vary from state to 

state. In general, BACT is required of those new sources and modifications to existing 

sources which exceed some specified trigger level. The trigger is based on emission rates. 

States will have differing guidelines on calculating emissions. Therefore, the appropriate 

state permitting officials (see Appendix I) must be consulted at this stage in the process. 

V. DEFINITIONS 

This guideline uses "permit" to refer to what different states call permits, licenses, 

approvals, and plant approvals. The specific definitions of terms may vary from state to 

state. The applicant must work with each states' definitions. Therefore, the state 

permitting officials listed in Appendix I should be consulted. 

VT. IDENTIHCATION OF CONTROL ALTERNATIVES 

In carrying out a top-down BACT analysis, the applicant must first identify the 

most stringent control possible (usually referred to as Lowest Achievable Emission Rate, or 

LAER) and then quantify emissions. Since other alternatives will be compared against this 

top case, applicants should concur with the appropriate state contacts on what represents 

the most stringent control case. At this step of the BACT review process, no technically 

feasible alternative should be ruled out as a possible BACT candidate. Identifying control 

alternatives should not be limited to simply reviewing existing controls for the source 

category in question. The review must be broad enough to take into account controls 

applied to similar source categories and innovative control technologies. Finally, the 

alternatives identified should include the control alternatives representative of LAER for the 

source or category of source. 

The starting assumption for the top-down approach is that the most stringent control 

possible is BACT. The burden of proof for applying a less stringent control rests in the 

applicant's case specific evaluation of the control alternatives. If the most stringent control 

for a specific pollutant is selected, the BACT evaluation for that pollutant is stopped. 

However, further evaluation of that control option's effectiveness on other pollutants may 

be required. 

Failing to address the top case in an attempt to avoid stringent controls will result in 

the process being delayed while the applicant is required to reassess alternatives against the 

control option the permitting authority determines to be the top case. 

When searching the record to identify the top case, the applicant must seek 

information on control technologies used throughout the United States, as well as 

applicable foreign control technologies. For example, Scandinavian pulping facility 

controls, German boiler and incinerator technology and operation controls, and Japanese 

controls for flue gas desulfurization have traditionally met very stringent emission control 

limits. Also, emission testing information on these technologies may be available to help 

establish the level of performance achievable with the specific technology. 

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A. Types of Controls 

When identifying the top case and alternative control technologies, the following 

types of controls should be considered. 

1. Existing Control Technology: a control technology which has been proven in practice 

for the source category. This should include both emission limitations imposed by other 

jurisdictions and test results which reflect what was actually achieved in performance. 

2. Technically Feasible Alternatives: a control technology which has been demonstrated in 

practice on other source categories but has not been demonstrated in practice on the class or 

category of source under review. Applying a control technology to a source category in 

which it has not been demonstrated is called control technology transfer. 

3. Innovative Control Technology: a control technology that has never been applied to any 

source on a full scale, continuously operating basis. This technology may be chosen on the 

basis of bilot scale or short-term testing. In selecting an innovative control technology, 

there must be some reasonable level of expectation that the innovative options will outperform the demonstrated control. 

4. Using Production Processes. Fuels, and Coatings That Are Inherently Lower Polluting 

These options may be evaluated alone or in combination with add-on pollution control 

devices. Examples include adjusting raw material feed to reduce emissions, using 

methanol for low NOx applications, and using powder coatings instead of solvent borne 

coatings where technically feasible. In considering these options, it is especially important 

to work closely with the appropriate state permitting officials since much of the required 

information may be confidential or proprietary. 

5. Specific Design or Operational Parameters: These options may include such factors as 

combustion zone temperature, combustion zone residence time, automatic combustion 

controls, pressure drop across control equipment, etc. 

Both the source applicant and the reviewing agency should consider the use of clean 

processes, fuels, and solvents that are inherently lower polluting than what has been 

historically employed by a particular industry. The analyses for these alternatives should 

be conducted in the same manner as the analyses for more conventional BACT alternatives 

(described in later sections). A reviewing agency should seriously consider requiring die 

use of such alternatives if the BACT analysis justifies their use based on environmental, 

economic, and energy factors. Examples include the use of a dry process cement plant vs. 

a wet design; powder coatings vs. solvent-borne coatings; gas vs. fuel oil; electric boost or 

all-electric glass furnaces vs. fossil fuel fired; fluidized bed coal combustion vs. 

conventional firing, low sulfur residual oil, etc. 

B. Sources of Information on Control Alternatives 

There are numerous sources of information on control alternatives for various 

source categories. The following sources of information will be checked by the perr_dtting 

authority. Hence they must be considered by the applicant preparing a BACT analysis. 

1. BACT/LAER Clearinghouse 

All applicants should check the B ACT/LAER Gearinghouse prior to submitting an 

application. The information contained in the Clearinghouse should be summarized in the 

application. Reviewing agencies should verify that this information is correct and up-todate. 

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2. EPA/State/Local Air Quality Permits 

Applicants should be aware of permits issued for their industry. An effort must be 

made to obtain current information on BACT for these sources. Permitting agencies should 

maintain documentation of recent BACT determinations. 

3. Federal/State/Lccal Perrmmng Engineers 

Permitting engineers and engineering managers can provide information on projects 

under review for which BACT information may be available. BACT analyses under 

consideration will be available from these individuals before it appears in the Qearinghouse 

manual. 

4. Control Equipment Vendors 

Vendors have information on the most recent control technology, cost information, 

emission guarantees, and test results. 

5. Trade Associations 

Associations serving one sector often maintain permitting and emission test reports. 

Examples include the National Council for Air and Stream Improvement (NCASI) for pulp 

and paper industry, Electric Power Research Institute (EPRI) for electric generators and 

American Gas Cleaning Institute (AGO) for information on air pollution control 

equipment 

6. Agencies or Companies Outside the United States 

These groups should be consulted for information on the most recent advances in 

control technologies, control costs, test results, etc. 

7. Inspection/Performance Test Reports 

Recent test data may be useful in establishing emission limitations for sources. 

Inspection and performance test data may also reveal potential problems with a control 

technology or specific equipment 

8. Technical Papers and Journals 

VTI. EFFECTIVENESS RANKING OF CONTROL ALTERNATIVES 

Once the applicant has identified the appropriate control alternatives, the applicant 

should rank them in order of control effectiveness, with the most effective control 

alternative at the top. This list should present an array of control alternatives, showing 

control efficiencies, expected emissions, economic costs, environmental benefits, energy 

costs, and other costs. The applicant should prepare a chart for each pollutant and for each 

emissions unit, or small group of units in the BACT analysis. These charts should be used 

to compare the control alternatives and to focus the selection of a control option as BACT. 

Vm. EVALUATION OF CONTROL ALTERNATIVES 

Three criteria are to be used if the applicant proposes using a control technology 

less effective than the top case. These three criteria are: 

1. energy impacts 

2. environmental impacts, and 

3. economic impacts. 

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Since the permitting agency will use these criteria in its decision making process, it 

is important that applicants provide fully documented estimates of the emissions using 

alternative control as well as quantitative and qualitative environmental, energy, and 

economic impacts as described in Section DC The evaluation process should be conducted 

in an incremental manner, from the top-down. The first step in this approach is to 

determine, for the emission source in question, the most stringent control available for a 

similar or identical source or source category. If it can be shown that this level of control is 

technically or economically inappropriate for the source in question, then the applicant 

should determine the next most stringent level of control and evaluate it similarly. This 

process continues until the BACT level under consideration cannot be eliminated by any 

substantial or unique technical, environmental, or economic objections. Thus, the topdown approach shifts the burden of proof to the applicant who must justify why the 

proposed source is unable to apply the best technology available. It also differs from other 

processes in that it requires the applicant to analyze a control technology only if the 

applicant opposes that level of control; other processes require a full analysis of all possible 

types and levels of control above the baseline case. If the applicant accepts the top 

alternative in the listing as BACT from an economic energy standpoint, the applicant 

proceeds to consider whether collateral environmental impacts would justify selection of an 

alternative control option. 

TX. IMPACT ANALYSIS OF CONTROL ALTERNATIVES 

There are three main impacts to be examined in a BACT analysis. These are: 

a. environmental impacts 

b. energy impacts 

c. economic impacts 

Although the impact analyses are die important part of the selection process, the 

effectiveness of the control alternatives will be the decisive factor affecting BACT selection. 

A, Environmental Impacts 

The first analysis is for environmental impacts. The applicant should estimate the 

net environmental impact associated with each control alternative. Both beneficial impacts 

and adverse impacts should be discussed and quantified, where possible. The analyses 

should be presented in the form of the incremental impact of each control alternative relative 

to the most stringent system identified as a control alternative. 

The BACT determination, however, is totally independent of die amount or 

increment on air quality resources available. Insignificant air quality impact cannot provide 

a basis for accepting a less stringent control technology. The only case where the modeled 

impact of the proposed emissions should influence the emission limitation is when that 

modeling shows exceedances of die air quality standards or increments. In diis case, die 

applicant must choose between using a control more stringent than BACT or changing the 

site location. 

When weighing environmental impacts, the applicant should consider all air 

pollutants and the impact of other environmental areas affected by the control alternative. 

This includes air pollutants which are not currendy regulated under die Clean Air Act but 

which may have a significant environmental impact On June 3,1986, the Administrator of 

die EPA remanded a PSD permitting to Region 9, instructing the Region to consider die 

effects of unregulated air pollutants when making a BACT determination for regulated 

pollutants. The analysis of unregulated air pollutants should be directed at developing an 

inventory of potential pollutants from a proposed source and evaluating the impact on those 

pollutants of each control alternative being considered for BACT. 

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The following is a brief outline of some, but by no means alL, of the environmental 

categories that should be considered during an analysis of environmental impacts. 

1. Impacts on air quality 

visible emissions 

odor 

visibility impairment 

toxic air pollutants 

noncriteria air pollutants 

dioxin/furans 

heavy metals 

acid gases 

non-photochemically reactive or toxic solvents 

etc. 

2. Impacts on water quality 

3. Solid waste disposal impacts 

4. Other environmental Impacts 

5. Noise 

6. Steam plumes from cooling towers 

7. Potential for accidental releases 

8. Reliability (or die potential for rnalfunction and downtime) 

Where approximately the same degree of emission reduction can be achieved by 

different technologies, preference should be given to the technology diat achieves die 

reduction with the greatest degree of pollution prevention. For example, use of either low 

VOC coatings or utilizing carbon adsorption with reuse of the solvent are generally 

preferable to utilizing a thermal or catalytic incinerator. 

B, Energy Impacts 

The second analysis is for energy impacts. In analyzing energy impacts, the 

applicant should estimate the direct energy impacts of the control alternatives in units of 

energy consumption (Btus, kWh, barrels of oil, tons of coal, etc.). The energy 

requirements of die control options should be shown in terms of total and incremental 

(units of energy per ton of reduction) energy costs. 

The analysis of energy impacts should also identify the type and amount of scarce 

fuels in the region diat would be required. The analysis should also recognize the perils of 

relying on inherendy low polluting fuels in lieu of controls since such decisions could 

result in greater emissions in die future due to unforeseen national energy policies or 

availability. 

C. Economic Impacts 

The third analysis is for economic impacts. In evaluating the economics of various 

BACT control options, primary consideration should be given to the cost effectiveness of 

an option and not to die economic situation of the source applicant For control 

technologies that have been proven for die source category under review, the economic 

impact of requiring this technology on a source under review is less imponant than the cost 

effectiveness. There are two measures of cost effectiveness. These include: average cost 

effectiveness (total annualized costs of control divided by annual emissions reduction, or 

the difference between baseline emission rate and the controlled emission rate), and 

incremental cost effectiveness (dollarsper incremental ton removed). Incremental costs 

should not be used as the basis for justifying the elimination of a control option. However, 

in limited circumstances, such as when comparing two levels of control for the same 

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control device, incremental cost may be utilized in conjunction with the average cost 

effectiveness to justify the elimination of the more stringent control level. 

In the analysis of economic impacts, die applicant should estimate die approximate 

costs of the different emission control alternatives. The analysis should include a complete 

explanation of procedures used for assessing the economic impacts, any supporting data, 

and an itemization and explanation of all costs. Credit for tax incentives should be 

included, along with credits for product recovery costs and by-product sales generated 

from the use of die control system. 

In evaluating the relative cost effectiveness of alternatives, calculations should be 

based on allowable emissions at maximum design capacity for 8,760 hours per year. If 

permit condition(s) limit operation to less than 8,760 hours per year, the analysis may also 

include data based on the allowed operation. Baseline emissions used to determine the 

degree of pollution reduction must be based on a realistic scenario of the upper bound of 

uncontrolled emissions from the source, and must be derived in a manner consistent with 

the procedures specified in EPA's Draft New Source Review Workshop Manual (October 

1990). Emission reduction credit can be taken for using inherently lower polluting 

processes. 

Annual costs should include the operation and maintenance cost plus die annualized 

cost for capitol and design engineering. The capitalization should be based on the average 

useful life of equipment. The economic life of a control system typically varies between 10 

and 20 years and longer and should be determined consistent with data from EPA cost 

support documents and IRS Class Life Asset Depreciation Range System. 

Applicants are responsible for fully documenting all relevant cost information. 

Vendor quotations or other reliable means should be die primary basis for estimates. Cost 

estimates should be derived using die most recent methods included in OAQPS Control 

Cost Manual (EPA 450/3-9-006, January 1990), and Appendix B (Estimating Control 

Costs) of EPA's Draft New Source Review Workshop Manual (October 1990), and any 

subsequent revisions to these manuals. Whenever the cost estimates are outside die range 

contained in these documents, die applicant is responsible for substantiating die estimates. 

The applicant must note the year used in cost estimates and adjust all calculations to reflect 

costs for that year. The limits of the process segr ->n ro be costed (or control system 

battery limits) should be specified in the BACT analysis and should have design parameters 

consistent with those that would achieve the emission estimates used in other portions of 

the application (i.e., dispersion modeling inputs, permit emission limits). Table 1 below 

summarizes some design parameters that are important in determining system costs. 

Table 1 Control System Design Parameters Examples 

Control Design Parameter Example 

Wet Scrubbers Scrubber liquor (water, chemicals, etc.) 

Gas pressure drop 

Liquid! gas ratio 

Carbon Absorbers Specific chemical species 

Gas pressure drop 

lbs. carbon! lbs. pollutant 

Condensers Condenser type 

Outlet temperature 

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Incineration Residence time 

Temperature 

Specific collection area (fYflcfm) 

Voltage density 

Air to cloth ratio 

Pressure drop 

Space velocity 

Ammonia to NOx molar ratio 

Pressure drop 

Catalyst life 

SOURCE: EPA Draft New Source Review Workshop Manual (October 1990). 

Electrostatic Precipitator 

Fabric Filter 

Selective Catalytic Reduction 

A complete economic analysis should compare costs of controls both within the 

specific source category under review and, as a comparison of costs, for other industries, 

on die basis of dollars per ton of pollutant removed. The analysis should also represent the 

control option costs in terms of cost per unit of production at full capacity (8,760 hours per 

year) and die control cost as a percent of the total project cost If permit condition(s) limit 

operation to less than 8,760 hours per year, the analysis may also include data based on die 

allowed operation. 

The analysis must be source specific, but should also be general enough to consider 

normal costs for doing business in a given field. A demonstration by an applicant diat it 

cannot afford to construct a facility using the most stringent technology does not allow the 

more stringent technology to be rejected as BACT. Rather it is a statement of whether die 

applicant is financially capable of conducting business in that field. 

X. ENFORCEABIL-TY 

The BACT determination for each pollutant must result in a federally enforceable 

permit BACT must be specified not only in terms of a control technology, but also in 

terms of emission limits and/or design, equipment, work practice, or operational standards 

(temperature, pressure drop, flow rates, pH control, etc.) that are federally enforceable. 

The BACT limits must be point specific and must include appropriate averaging times, • 

reference test methods, and a method for ensuring continuous compliance. 

This guideline was adopted by die NESCAUM Board of Directors on ??': 

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APPENDIX I 

STATE BACT CONTACTS 

CONNECTICUT 

S. Amarello, E. Bouffard, S. Peplau 203/ 566-8230 

Connecticut Department of Environmental Protection 

Bureau of Air Management 

165 Capitol Avenue 

Hartford, CT 06106 

MAINE 

M. Cone, E. Kennedy 207/ 289-2437 

Maine Depanment of Environmental Protection 

Bureau of Air Quality Control 

State House Station 17 

Augusta, ME 04330 

MASSACHUSETTS 

J. Belsky, D. Howland, D. Squires, V. Steeves 617/ 292-5630 

Massachusetts Department of Environmental Protection 

Division of Air Quality Control 

One Winter Street, 8th Floor 

Boston, MA 02108 

NEW HAMPSHIRE 

A. Bodnarik, D. Davis 603/ 271-1370 

New Hampshire Department of Environmental Services 

Air Resources Division 

64 North Main Street, Caller Box 2033 

Concord, NH 03302-2033 

NEW JERSEY 

Minor Source Air Pollution Control Permits 

Chief, Bureau of New Source Review 

New Jersey Department of Environmental Protection 

Division of Environmental Quality 

401 East State Street, CN 027 

Trenton, NJ 08625 

Major Source Air Pollution Control Permits 

Chief, Bureau of Engineering and Regulatory Development 

New Jersey Depanment of Environmental Protection 

Division of Environmental Quality 

401 East State Street, CN 027 

Trenton, NJ 08625 

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NEW YORK 

J. Davis, R. Parker 518/457-2044 

New York Department of Environmental Conservation 

Division of Air 

50 Wolf Road 

Albany, NY 12233 

RHODE ISLAND 

D.McVay 401/277-2808 

Rhode Island Department of Environmental Management 

Division of Air and Hazardous Materials 

291 Promenade Street 

Providence, RI 02908 

VERMONT 

D. Elliott, B. Fitzgerald, J. Perreault 802/ 244-8731 

Vermont Department of Environmental Conservation 

Air Pollution Control Division 

Building 3 South 

103 South Main Street 

Waterbury, VT 05676 

OTHER CONTACTS 

NESCAUM 

M. Bradley, N. Seidman 617/ 367-8540 

85 Merrimac Street 

Boston, MA 02114 

EPA Region I 

J. Courcier 617/565-3260 

L.Hamjian 617/565-3250 

JFK Federal Building, Room 2311 

Boston, MA 02203 

EPA Region n 

W. Baker, K. Mangels 212/264-2517 

26 Federal Plaza 

New York, NY 10278 

BACT gdln-rev 3/91;3/22/91 

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