BEST AVAILABLE CONTROL TECHNOLOGY (BACT) REQUIREMENTS

Roland C. Hea, P.E.

Colorado Air Pollution Control Division

2

Main PSD Program Requirements

2

1. Install Best Available Control Technology (BACT)

2. Perform air quality analysis to assess impacts on air quality (NAAQS and PSD increments)

3. Perform Class I Area analysis to assess impacts on national parks and wilderness areas or other Class I Areas

4. Perform additional impacts analysis5. Provide opportunities for public

involvement

3

BACT – Major Topics3

When does BACT apply Steps in the “Top Down” BACT analysis What does a BACT determination and

limit look like Greenhouse gas (GHG) BACT issues State (Colorado) perspectives

4

Best Achievable Control Technology (BACT) Overview

4

Pollutant specific emissions limit, case-by-case Takes into account energy, environmental, or economic

impacts

Limit must be at least as stringent as applicable New Source Performance Standard (NSPS) and/or National Emission Standard for Hazardous Air Pollutants

(NESHAP)

Selected by “Top Down” BACT analysis1. Identify all available control technologies

2. Eliminate technically infeasible control options

3. Rank remaining control technologies by its effectiveness (considering economic, energy and environmental impacts)

4. Evaluate most effective controls and document results

5. Select BACT

5

5

BACT Applicability

Identify emissions units that are subject to BACT

Applies to each individual new or modified affected emissions unit or activity at which a net emissions increase would occur

Perform BACT analysis at each of the applicable emissions units for each regulated pollutant subject to PSD review

6

BACT Analysis Step 16

Identify all available air pollution control technologies, regardless of cost

Information sources Review RACT/BACT/LAER Clearing House

http://cfpub1.epa.gov/RBLC/ Look at BACT and LAER Control technology vendors Federal/state/local NSR permits Environmental consultants Technical journals (e.g., Journal of Air and Waste

Management Association) and air pollution conferences

EPA’s Draft October 1990 NSR Workshop Manual

7

BACT Analysis Step 1 (cont.)

7

Include technologies used outside the U.S. Include controls applied to similar

categories and gas streams Review applicable NSPS and NESHAP

(including MACT), which define minimal “floor” for BACT

Consider Inherently lower-emitting processes/practices Add-on controls (e.g., scrubbers, fabric filters) Combination of inherently lower-emitting

processes/practices and add-on controls

8

BACT Analysis Step 1 (cont.)

8

EPA has not considered BACT requirement as a means to redefine design of a source when considering available control technology For example, EPA does not require

coal-fired electric generators to consider gas-fired electric turbines

Colorado takes the same position on this issue

9

BACT Analysis Step 29

Eliminate technically infeasible control options

Source must demonstrate technical infeasibility, based on physical, chemical, and engineering principles

If someone has issued a permit requiring a certain technology or emission limit, assumption is that the technology or limit is technically feasible (Colorado uses its permitting discretion to assess this aspect)

10

BACT Analysis Step 2 (cont.)

10

Where control technology has not been installed and operated successfully on the type of source under review, feasibility is determined based on Availability (i.e., product has reached licensing

and commercial sales stage of development) Applicability

Control alternative has or will be deployed on same or similar source type, or

Could be used on source based on physical and chemical characteristics of pollutant-bearing gas stream

11

BACT Analysis Step 2 (cont.)

11

Applicant may show technical infeasibility through an unresolvable technical difficulty with applying the control (e.g., size of unit, location of proposed site, operating problems related to specific circumstances of source)

Applicant may not use cost to demonstrate infeasibility, but may be considered in economic impacts portion of BACT analysis

12

Class exercise12

Please see handout

13

BACT Analysis Step 313

Rank remaining control technologies according to control effectiveness. For each pollutant, list includes – Control efficiency (percent of pollutant

removed)– Expected emissions reduction

(tons/year)– Economic Impacts– Environmental Impacts (e.g., significant

impact on surface water)– Energy Impacts

14

BACT Analysis Step 3 -Control Efficiency

14

Two key questions How to compare apples to apples

(deciding common unit for comparing the emissions of each option)

How to analyze control techniques that can operate over a wide range of emission performance levels

Tips: what to watch for Observations: major issues in this area

15

BACT Analysis Step 3 - Expected Emissions Reductions (tons/year)

15

Calculate annual emission projections for each option using standard PTE approach

Options ranked with top spot going to control technology option that achieves lowest emissions level, in descending order of emissions control effectiveness

16

BACT Analysis Step 3 – Economic and Other Impacts

16

Applicant prepares list to display top-down ranking, and for each alternative includes data on Economic impacts Environmental impacts (i.e., non-air quality impacts)

Energy impacts

17

BACT Analysis Step 3 – Economic Impacts

17

Economic impacts include Average cost effectiveness (dollars per ton of

emissions reduced) based on data from similar sources

Incremental cost effectiveness Affordability to source is not as relevant as

average and incremental cost-effectiveness Where control technology has been successful

for similar sources, applicant need to document significant cost differences for its source to eliminate control alternative

18

BACT Analysis Step 3 – Economic Impacts (cont.)

18

Key issues for cost effectiveness Ensure that design parameters used in

cost estimates are consistent with emissions estimates used in other portions of PSD application (e.g., dispersion modeling inputs and permit emission limits)

Ask for more detailed cost data if cost projections appear excessive in light of recent cost data

19

BACT Analysis Step 3 – Economic Impacts (cont.)

19

Average cost effectiveness Total annualized costs of control, divided

by Annual emission reductions (the difference

between the baseline emission rate and the controlled emission rate)

Major issues Underestimation of PTE Overestimation of annualized costs Inclusion of indirect costs that should not

be considered in a BACT analysis (see EPA control cost manual)

20

BACT Analysis Step 3 – Economic Impacts (cont.)

20

Incremental cost effectiveness compares costs and emissions performance level of a control option to the next most stringent option

Calculation Total annualized cost of option 1 minus

total annualized cost of option 2 (less stringent option), divided by

Option 2 emission rate minus option 1 emission rate

21

BACT Analysis Step 3 – Environmental Impacts

21

Environmental impacts should include any significant or unusual other media impacts (e.g., water or

solid waste) Usually limited to discharges with potential for causing

adverse environmental effects Quantify mass and composition of discharges and

consequences of release Impacts on ground water and local surface water; whether

applicable water quality standards will be met; availability/effectiveness of mitigation techniques

Quality and quantity of solid waste to be stored, disposed of or recycled (including permeability, water retention, leachability, hazardous characteristics, etc.)

Irreversible or irretrievable commitment of resources (e.g., scarce water resources)

Significant differences in noise levels, radiant heat, dissipated static electrical energy and greenhouse gas emissions

22

BACT Analysis Step 3 – Environmental Impacts (cont.)

22

Environmental impacts should include the relative ability of each control alternative to control emission of HAPs and visibility impacts

Examples where environmental factors have made a difference in a BACT analysis Aqueous versus anhydrous ammonia Dry vs. wet scrubbing for a coal-fired power plant Local water table low, thus dry cooling better option

Environmental concerns become important when site-specific receptors exist Application to tribal issues – discuss with class

23

BACT Analysis Step 3 – Energy Impacts23

Generally consider only direct energy consumption of alternative control technologies

Quantify any benefits or penalties Typically can monetize these impacts

and factor them into the economic impacts analysis

24

BACT Analysis Step 424

Evaluate most effective controls based on all the factors in Step 3

Document results

25

Sample Top-Down BACT Determination25

Small group exercise: Each group makes a recommendation on BACT

Discuss results

26

BACT Analysis Step 526

Ultimate BACT decision is made by permitting agency after public review

BACT is based on most effective control option for which adequate justification for rejection not provided

Public gets at least 30 days to review draft permit Practical advice for reviewers

Public comment hearing provisions Permitting agency will consider any new

information revealed during comment period, including recent permit decisions

27

Implementing BACT27

BACT is an emission limit that Is needed for each emission unit at a source,

subject to PSD for each pollutant subject to review that is emitted by source

Must be met continually at all levels of operation Alternate BACT limits may be needed for other

operational scenarios (e.g., startup/shutdown) Must protect short-term ambient standards

(limits and averaging times) Specifies a control technology or practice,

numerical limit and averaging time

28

Implementing BACT (cont.)28

Incentive to operate efficiently BACT can be made more stringent if initial

BACT emission levels would result in a NAAQS or a PSD increment to be exceeded

Proposed source or modification still has to demonstrate compliance with other standards included in the PSD analysis

Must be enforceable as a practical matter Monitoring considerations for demonstrating

on-going compliance

29

Greenhouse Gas Considerations

29 Relatively new, agencies have less

experience implementing Energy efficiency Setting numerical limits and averaging

times Carbon capture and sequestration See

http://www.epa.gov/nsr/ghgpermitting.html

30

Summary30

Major stationary sources and major modifications that are subject to PSD must conduct a BACT analysis

Each BACT analysis is case-by-case and is based on evaluation of all available control technologies

Alternatives are ranked in descending order of control effectiveness

The most stringent or top alternative is BACT unless the applicant demonstrates that technical considerations or energy, environmental or economic impacts justify the elimination of the control option