BART Control Analysis

WESTARAugust 31, 2005

EPA Office of Air Quality Planning and StandardsTodd Hawes

Hawes.todd@epa.gov

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Overview

1. List all available control options for each pollutant

2. Eliminate technically infeasible options

3. Evaluate alternatives

4. Analyze Impacts

5. Select the best alternative

Note: – repeat for each pollutant– guidance only for non-EGUs – States have discretion in how to do analysis

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Step 1: List Available control options

• Is the source already controlled?– List the improvements that can be made to current controls– If the source is subject to MACT and that represents the best

control, then MACT can satisfy BART

• If the NSPS, BACT, or LAER determination is old, then list the most current options (e.g. PSD permits from similar sources)

• Three types of controls– Use of or improvement of add-on (e.g. scrubbers)– Pollutant prevention (e.g. fuel switching)– Combinations

• Note – if the source has the most stringent controls in place – you are done – that is BART

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Step 2: Eliminate Technically Infeasible Options

• Technically infeasible means not available or not applicable to that specific unit– Not used in practice yet or not commercially

available

• Use judgment to narrow the list of options if there are options that are clearly inferior– For example, controls that are more costly but

don’t get the reductions of other controls

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Step 3: Evaluate Alternatives

• Compare emission control effectiveness using a common metric (lb/mmBtu)

• Look at different performance levels– Most stringent achievable looking at recent

regs. and performance data

• Consider any special circumstances and whether improved performance may be achievable on existing controls

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Step 4: Analyze Impacts (the five factors)

1. Cost impacts

2. Energy impacts

3. Nonair environmental impacts

4. Remaining Useful Life

5. Improvement in visibility

Note – a state is free to determine the weight and significance of each factor

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Cost ($/ton removed)

• Specify design parameters for each control option

• Identify average and incremental cost-effectiveness (see the guidelines for calculation of average and incremental costs)

Note: high capital costs may be cost-effective if the emission reductions are very large

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Energy

• Quantify to the extent practicable; analysis can be qualitative

• Questions:– Energy consumption/tons of emissions

removed (in units of energy and possibly dollars)

– Locally scarce fuels and economic impacts of using different fuels

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Non air quality impacts

• Generally consider significant or unusual impacts– For example, hazardous waste generation,

water quality, land use, resource use from each control option

– Quantify discharges when possible

• Assessment can be qualitative

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Remaining Useful Life

• If short, could be part of cost analysis

• Remaining useful life = date controls put in place – date facility halts operation

• Could choose a lesser control if short remaining useful life, but with permit constraints if source does not shut down as planned

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Visibility Impacts

• Degree of visibility improvement expected from controls

• Run CALPUFF at pre-control and post-control emission rates for SO2, NOx, and PM2.5

• Visibility impacts = 7th highest value of difference of pre-control and post-control runs (use 24-hour maximum actual emission rates and compare to natural conditions)

• A threshold may be used but is not required and it may be lower than 0.5 ddv. Consider magnitude, frequency, and duration of impacts.

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Final Step – Select the Best Alternative

• Develop a table or array of the options – include the emission rate, the control efficiency, and the five factors

Control option A

Emission Rate

Control Efficiency

Emission Reduction

Cost Energy impacts

Nonair impacts

Visibility impacts

Control option B

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Final Step – Select the Best Alternative (cont.)

• Select the best emission reduction achievable considering all other factors

• Consider mitigating factors or factors making the case stronger for best controls (i.e. visibility)

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Presumptive controls for >200 MW EGUs

• SO2: 95% control or 0.15 lbs/mmBtu

• NOx:– In NOx SIP call area, extend use of controls to

year-round.– Outside NOx SIP call area, current combustion

controls• 0.2 – 0.45 lbs/mmBtu, depending on coal and

boiler type

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Presumptive NOx emission limits(lb/mmBTU)

Dry-bottom wall-fired (75 units subject to presumptive limits) Bituminous 0.39 Sub-bituminous 0.23 Lignite 0.29

Tangential-fired (110 units subject to presumptive limits) Bituminous 0.28 Sub-bituminous 0.15 Lignite 0.17

Cell Burners (27 units subject to presumptive limits) Bituminous 0.40 Sub-bituminous 0.45

Dry-turbo-fired (4 units subject to presumptive limits) Bituminous 0.32 Sub-bituminous 0.23

Wet-bottom tangential-fired (3 units subject to presumptive limits) Bituminous 0.62

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Appendix: Air Control NET

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What is AirControlNET?

• A control strategy and costing analysis tool for use in conducting analyses of air pollution regulations and policies for criteria pollutants. Costs estimated are those for direct control of sources.

• “Next generation” tool derived from the Emission Reduction and Cost Analysis Model (ERCAM)-VOC & ERCAM-NOx, which were used for the 1997 PM/O3 NAAQS and 1999 Regional Haze Rule RIAs.

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What is AirControlNET?

• A PC-based, relational database system in which control technologies are linked to sources within EPA emissions inventories.– More than 800 control measures/source category

combinations. Costs can be generated for various year dollars (1990 to 2004).

– Controls applicable to point (utility and non-utility), area, nonroad, and onroad mobile sources as provided in EPA's Emission Inventories (NEI).

– Provides Emission reductions and Control Cost information (capital, O&M, and other cost components).

– Is available on CD; can be run on most desktop/laptop computers.

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What Can AirControlNET Be Used for?

• Analyze the effects of control strategies at various geographic scopes (national, regional (built-in), State, CMSA)

• Input to air quality models (e.g., CMAQ, CAMx), and economic impact models (e.g., EMPAX-CGE used by EPA)

• Provide control measure information to States and Nonattainment Areas

• Provide “control case” scenario emission inventories for dispersion modeling

www.epa.gov/ttnecas1/aircontrolnet.htm