Concepts and Practical Application

Concepts and Practical Application
BACT/ LAER Evaluation Concepts and Practical Application Mike Coldiron, P.E. Air Permits Division Texas Commission on Environmental Quality Advanced Air Permitting Seminar 2016 BACT = Best Available Control Technology LAER = Lowest Achievable Emission Rate

Things to Remember Texas and EPA rules require a control technology analysis. Texas and EPA BACT evaluations are similar. Some aspects of a LAER evaluation are different from Texas and EPA BACT evaluations. Practical aspects of the evaluation process must be considered. EPA = Environmental Protection Agency BACT = Best Available Control Technology LAER = Lowest Achievable Emission Rate Image created by Ryan Sun from the Noun Project.

Legislative & Regulatory Basis
Texas Health & Safety Code Clean Air Act 1990 Texas Administrative Code, Title 30 Code of Federal Regulations, Title 40 TX Health & Safety Code: Title 5, Subtitle C, Chapter 382, Subchapter C §§ (b) Clean Air Act 1990: Title 1, Part C, Subpart I, Sections 165 and 173 Title 30 Texas Administrative Code (30 TAC) §§ , , 151, and Title 40 Code of Federal Regulations (40 CFR) §51.165 Image of scales created by Ralf Schmitzer from Noun Project.

Rule Control Technology Requirements
Define minimum level of control. Help define BACT and LAER. Applicable in addition to BACT/LAER. Rule requirements define a minimum level of emission control for sources/source types that are subject to the rule. These other control technology requirements help define a minimum level of control for BACT and LAER. These requirements are applicable in addition to BACT/LAER. These rules have recordkeeping, reporting, testing, and monitoring requirements and these types of requirements must be added to the permit to ensure enforceability of the emission reductions.

Control Technology Requirements
GACT RACT MACT BACT LAER Generally Reasonably Maximum Best Lowest Achievable Available Control Emission Technology Rate Image of flare created by Creative Stall from Noun Project. BDT Best Demonstrated Technology = NSPS

Control Technology Requirements
Least Stringent Most Stringent GACT RACT BDT MACT BACT LAER GACT = Generally Achievable Control Technology RACT = Reasonably Achievable Control Technology BDT = MACT = Maximum Achievable Control Technology BACT = Best Available Control Technology LAER = Lowest Achievable Control Technology The chart of relative stringency of rule required controls with BACT and LAER is for illustrative purposes only. Control technology requirements are not sequentially increasing levels of control. Rather they exist as a set of over lapping continuums. This is partially due to the fact that the rules apply to different types of sources of varying emission rates and air contaminants. For example, there would never be an overlap between GACT and LAER. GACT applies to area sources of hazardous air pollutants (HAP) (<10/25 tons per year [tpy]) while LAER is only applicable to major sources of a specific pollutant for which an area does not meet the National Ambient Air Quality Standards (NAAQS). As noted below, control technology requirements are sometimes equal. Image of flare created by Creative Stall from Noun Project.

Control Technology Relationships
BACT is never less stringent than RACT regardless of source location. Coating VOC content and application equipment meet Chapter 115 statewide. NOx limits for heaters and boilers meet ESAD requirements in Chapter 117 statewide. Since BACT cannot be less stringent than RACT, this limit applies essentially statewide for new sources. This position is clearly stated in the TCEQ guidance document for Evaluating Best Available Control Technology in Air Permit Applications (April 2001) Appendix C - Frequently Asked Questions as follows: Q: Is location a factor in making a BACT determination? A: No. A BACT evaluation, as described in the BACT guidance document, is the same for all permits and permit amendments, regardless of where a facility is located. However, there may be additional regulations that may apply to existing and new facilities depending on location. An example of this would be the TCEQ Title 30 Texas Administrative Code (30 TAC) Chapter 115 requirement to use compliant coatings in certain counties of Texas. Q: If a performance level is established as Reasonably Available Control Technology (RACT), does it automatically become the floor for BACT? A: Yes. BACT is at least as stringent as RACT and may be more stringent. RACT is the minimum required by the U.S. Environmental Protection Agency to meet the specific RACT provisions of the Federal Clean Air Act (FCAA) and it applies to both existing and new sources of emissions regardless of permitting status. However, not everything in the TCEQ State Implementation Plan (SIP) regulations are RACT. Some SIP rules go beyond RACT to achieve attainment of the National Ambient Air Quality Standards as required by the FCAA; however, they do not establish the floor for BACT. Image of flare created by Creative Stall from Noun Project.

Control Technology Relationships
Sometimes BACT and LAER are equal. NG fired boilers > 40 MMBtu/hr with SCR Combined cycle gas turbines with dry low NOx burners and SCR Surface coating operation with process controls, high VOC capture efficiency, and a thermal oxidizer MMBtu/hr = million British thermal units per hour SCR = selective catalytic reduction NOX = nitrogen oxides VOC = volatile organic compound

What is BACT? (State) 30 TAC 116: Best available control technology with consideration given to the technical practicability and the economic reasonableness of reducing or eliminating emissions from a facility. State Definition 30 TAC Chapter 116 can be found at: The state definition of BACT can be found in 30 TAC § at : (1) Best available control technology (BACT)--An air pollution control method for a new or modified facility that through experience and research, has proven to be operational, obtainable, and capable of reducing or eliminating emissions from the facility, and is considered technically practical and economically reasonable for the facility. The emissions reduction can be achieved through technology such as the use of add-on control equipment or by enforceable changes in production processes, systems, methods, or work practice. The Air Pollution Control Reference Guide can be found at:

What is BACT? (Federal) 40 CFR §51.165(xl): An emissions limitation based on the reduction of each potentially emitted pollutant from any proposed major stationary source or major modification, which TCEQ determines is achievable after considering several factors. Federal Definition The federal definition also describes Secondary BACT. Most commonly, or more recently, applied to maintenance, start-up, and shutdown (MSS) operations. The federal definition of BACT can be found in 40 CFR §51.165(xl) at: idx?SID=81431fec7e14379d57c29ccc6aa55fdf&mc=true&node=se _1165&rgn=div8. Best available control technology (BACT) means an emissions limitation (including a visible emissions standard) based on the maximum degree of reduction for each regulated new source review (NSR) pollutant which would be emitted from any proposed major stationary source or major modification, which the reviewing authority, on a case-by-case basis, taking into account energy, environmental, and economic impacts and other costs, determines is achievable for such source or modification through application of production processes or available methods, systems, and techniques, including fuel cleaning or treatment or innovative fuel combustion techniques for control of such pollutant. In no event shall application of best available control technology result in emissions of any pollutant which would exceed the emissions allowed by any applicable standard under 40 CFR Part 60 or 61. If the reviewing authority determines that technological or economic limitations on the application of measurement methodology to a particular emissions unit would make the imposition of an emissions standard infeasible, a design, equipment, work practice, operational standard, or combination thereof, may be prescribed instead to satisfy the requirement for the application of BACT. Such standard shall, to the degree possible, set forth the emissions reduction achievable by implementation of such design, equipment, work practice or operation, and shall provide for compliance by means which achieve equivalent results.

What is BACT? (Federal) Must also consider impacts on:
Energy consumption Air toxics Economic effect on the site

When is a BACT review required?
Initial Permit Amendments PBR Incorporation by Consolidation Standard Permit Incorporation by Consolidation Initial permit BACT requirements are located in 30 TAC (a)(2(C): (C) Best available control technology (BACT) must be evaluated for and applied to all facilities subject to the TCAA. Prior to evaluation of BACT under the TCAA, all facilities with pollutants subject to regulation under Title I Part C of the Federal Clean Air Act (FCAA) shall evaluate and apply BACT as defined in § (c)(1)(A) of this title (relating to Prevention of Significant Deterioration Requirements). Permit amendment BACT requirements are located in 30 TAC (b)(2): (2) Any person who requests permit amendments must receive prior approval by the executive director or the commission. Applications must be submitted with a completed Form PI-1 and are subject to the requirements of § of this title (relating to General Application). When you are consolidating by incorporation previously authorized permits by rule (PBRs) and standard permits (SPs) at renewal or during an amendment, those sources are essentially being re-authorized and are required to meet BACT. This is further discussed in the roll-in memo, which is located at: Image of clock created by James Rainsford from Noun Project.

Evaluation Methods Three-Tiered Approach Top-Down Method

Tier I Emission reduction performance levels accepted as BACT in recent permit reviews Same process and/or industry Consider new technical developments This is discussed in greater detail in APDG 6110: Air Pollution Control How to Conduct a Pollution Control Evaluation Which is located at:

Tier I bact resources Recently issued permits Turbine list
Coatings Completed Projects List TCEQ BACT Tables on Web Copies of issued permits and technical reviews are available on the remote document server, which is located at: The Turbine List is updated frequently and is located at: The Coatings Completed Projects List is available upon request by contacting the Coatings Team. Any team member will be able to provide assistance. The general telephone number of the Air Permits Division is (512) The BACT Tables are located on the Air Permits portion of the TCEQ web site under Index of Common Permitted Facilities. Just select the source type and scroll down to the Current BACT. This area of the web site is located at:

Tier I revisions APD staff:
Compiles statistics from recently issued permits Compares BACT guidance to recent permits Establishes new guidance

tier I metal parts painting overspray Filters
Current BACT Revised BACT The Coatings Team evaluated the permitted control efficiencies for all new permits and permit amendments for 2007, 2008, and The data was extracted from the Completed Coatings Projects List and plotted in Excel. The peak at 95% control efficiency represented BACT guidance at the time. An efficiency of 99% was selected as the new BACT guidance given the number of sources that were able to achieve this level of performance.

Tier I metal parts painting thermal oxidizer
Current BACT Revised BACT The Coatings Team evaluated the permitted control efficiencies for all new permits and permit amendments for 2007, 2008, and The data was extracted from the Completed Coatings Projects List and plotted in Excel. The peak at 95% control efficiency represented BACT guidance at the time. An efficiency of 98% was selected as the new BACT guidance given the number of sources that were able to achieve this level of performance.

Tier I BACT proposal supporting information
The permit or permit amendment application must provide supporting information to demonstrate that the proposed facility will achieve the performance specified in the permit application. The applicant may be required to submit additional engineering data after a permit has been issued in order to demonstrate further that the proposed facility will achieve the performance specified in the permit application. In addition, dispersion modeling, monitoring, or stack testing may be required. Ref 30 TAC (a)(2)(G) The supporting information may take the form of equipment vendor data, a detailed written proposal or guarantee, or lab or field test data. Image of data report created by Alfredo Hernandez from Noun Project. Image of certification created by parkjisun from Noun Project. Image of beaker created by Egorova Valentina from Noun Project. Back up proposal with vendor data Written proposal or guarantee Lab or field test data

What if tier I doesn’t fit?
Tier II

Tier II Different process or industry
Consideration of controls accepted as BACT in recent permits for similar air emission streams Detailed technical analysis may be required Used if BACT requirements have not already been established for a particular process/industry.

Tier II Example Tier II Example Top-Down Example LAER Example
Company B: 40 TPY SO2 Tier I BACT - Unestablished Tier II BACT - Caustic scrubber Company A: 35 TPY SO2 Tier I BACT - Caustic scrubber Company B: 40 TPY SO2 Tier I BACT – Unestablished TPY = tons per year Company A has a big production unit that produces a large amount of sulfur dioxide (SO2). Tier I BACT for this industry type is to use a caustic scrubber. Company B also has a big production unit that produces a large of amount of SO2; however, Tier I BACT has not yet been established for Company B’s industry type. The off-gas stream of Company B’s unit is similar to the off-gas stream of Company A in that the stream is the same size and concentration. A Tier II analysis suggests that Company B should use a caustic scrubber to meet BACT. Image of paperclip created by John Caserta from Noun Project.

Tier II Today It is rare for an industrial process to be so unique that BACT has not been established; Therefore, Tier II is used infrequently. Permitting began September 1, 1971 – 45 years ago. Given the amount of time that has elapsed, it is rare for an industrial process to be so unique that BACT has not been established or that the potentially applicable controls are not well known. Therefore, Tier II is used infrequently.

What if tier I and II doesn’t fit?
Tier III

Tier III Highly complex and quantitative
Numerous assumptions required for completion Time and resource intensive This is discussed in greater detail in APDG 6110: Air Pollution Control How to Conduct a Pollution Control Evaluation Which is located at:

Tier III Uses Determines BACT when hasn’t been established
Demonstrates established control technology is not economically reasonable The first use is the traditional use for this step of the evaluation process. The second use is much more commonly used today since the types of controls to reduce emissions from a process or exhaust stream is usually well known. This frequently amounts to a detailed analysis of why the proposed facility is so unique that Tier I and/or Tier II do not apply and that the types of controls typically applied via Tier I or Tier II are not cost effective.

Tier III Today It is rare for a technically feasible option to be unknown for an industrial process. Permitting began September 1, 1971 – 45 years ago. Given the amount of time that has elapsed, it is rare for an industrial process to be so unique that BACT has not been established or that the potentially applicable controls are not well known.

Tier iii – What to do Identify emission reduction options
Eliminate technically infeasible options Determine cost effectiveness ($/ton) The completion of a Tier III BACT analysis will result in the applicant choosing an emission reduction option(s) that is technically practicable and economically reasonable. In order to complete a Tier III evaluation, the applicant must provide a detailed technical and economic analysis, which should accomplish the following tasks: 1. Identify all emission reduction options. 2. Eliminate technically infeasible options. 3. Rank remaining emission reduction options in terms of total emissions reduced. 4. Perform quantitative cost analysis to determine the cost-effectiveness (dollars per ton of pollutant reduced) of each emission reduction option. 5. Select BACT based on cost-effectiveness and performance. More detail on this subject is located in Appendix G of the Air Pollution Control guidance document (APDG 6110). Rank by total emissions reduced BACT

Tier III – OAQps control Cost manual
VOC NOx SO2 and acid gas PM OAQPS – the EPA Office of Air Quality Planning and Standards PM = particulate matter The cost analysis methodology is described in detail in OAQPS Control Cost Manual. For other air contaminants, a similar approach should be used.

Tier iii – OAQPS control cost manual
Evaluate annualized capital cost Evaluate annualized operating cost Sum annualized costs and divide by TPY to be controlled ($/Ton) The OAQPS Control Cost Manual includes detailed examples for each of the air pollutants covered in the manual and included determination of annualized capital cost and annualized operating cost.

Tier III – data requirements
For equipment costs, use actual vendor quotes. Quotes should include utility requirements. For thermal controls, include the heating value of the stream in the evaluation. The design approach included in the chapters should not be used in developing equipment costs since the data and correlations are over 25 years old. A much better approach for estimating purchased equipment costs is to obtain a detailed vendor quote that is tailored to the process being evaluated. The quotes should be based on flow rates, pollutant concentrations, heating value (if applicable). The quotes should include the electrical load (kilowatts), fuel usage and reagent consumption, etc. Three vendor quotes are preferred, but two quotes will suffice in some cases. If multiple types of control equipment are being evaluated, the APD staff should be contacted to determine the number of quotes that should be provided.

Tier III – cost review Labor: typical wage x 1.5
Actual operating costs: electric, natural gas, and water Actual reagent Actual disposal Labor costs should be based on a typical wage x 1.5 to cover taxes and benefits. Operating costs should be based on actual electric, natural gas, water, reagent, and disposal costs. Rates from the utility companies should be provided as well as delivered cost estimates from chemical suppliers. Other cost resources such as EIA (Energy Information Administration) may be acceptable. The EIA cost information is located at:

U.S. Natural gas industrial price
$\ Thousand Cubic Ft Source: U.S. Energy Information Administration After reaching a peak of approximately $12 in 2008, natural gas prices have fallen sharply. Part of this is due to changes in demand and weather conditions. However, the long term trend appears that prices will remain close to $5 due to the significant increase in supply due to shale gas. Years

Tier III – Question When do you conduct a Tier III review?
Only if Tiers I and II fail to identify an emission control option. However, if the facility triggers Prevention of Significant Deterioration (PSD), you may conduct a Tier III review to identify all control technology options. Example: If the facility triggers PSD for NOX but no other pollutant, Tier III can be used for NOX only, and Tier I can be used for all other pollutants...OR...Tier III can be used for all pollutants. However, Tier I is not sufficient to satisfy BACT review requirements for PSD.

Three-Tiered Approach
Evaluation Methods Three-Tiered Approach Top-Down Method The Three-Tiered approach is similar to Top-Down. If both are done correctly, you should arrive at the same conclusion. EPA has agreed to accept the Three-Tiered Approach as equivalent to Top-Down for a PSD review when the following are considered: Recently issued/approved Texas permits Recently issued/approved permits in other states Control technologies contained within EPA’s RACT/BACT/LAER Clearinghouse (RBLC) RACT = Reasonably Achievable Control Technology The applicant must provide detailed information concerning any comparison or reasoning as to why one technology was chosen over another. This is especially true in cases where other “more stringent” technologies have been used at other locations in the past. It is not a sufficient argument for an applicant to state that a current project represents BACT simply because the previous project, at the same facility and/or a similar facility at the site, was recently approved as BACT with the proposed controls. It is important to ensure that any control technology advancements are considered in the control technology review (the reviewer should be aware that these advancements can happen at any time).

Top-Down Method Identify all control options
Covered in Tier I and Tier II of the Three-Tiered Approach.

Reduction Strategy Options
Pollution Prevention Equipment Specification & Monitoring Add-on Abatement Good Engineering Practice (GEP) Best Management Practice (BMP) Any of the following options or a combination may be proposed to satisfy BACT requirements. Pollution Prevention: can consist of process control methods or process changes that eliminate emissions or can be proposed to simply reduce emissions or to create an emission stream that is more susceptible to control. Equipment Specification/Monitoring: certain equipment that inherently has lower emissions and/or propose equipment monitoring. Add-on Abatement: scrubbers, oxidizers, flares, cyclones, baghouses, vapor recovery units, carbon adsorption systems, etc. (May also pose other concerns to consider, such as the generation of additional emissions.) GEP: effective design and efficient operation of equipment to minimize emissions. BMP: an operating practice or procedure that minimizes emissions.

Eliminate technically infeasible options Covered in Tier I and Tier II of the Three-Tiered Approach.

Eliminate technically infeasible options Rank remaining control options Covered in Tier I and Tier II of the Three-Tiered Approach.

Performance Elements Used in Ranking
Capture Efficiency Enforceability Reduction Efficiency In addition to reduction (control) efficiency, the remaining control options using Performance Elements should be considered in the ranking - Capture Efficiency: the percentage of uncontrolled emissions captured by a control device. May vary based on several parameters (air flow rates, the amount of enclosure of the source, temperature, throughput, etc.). Reliability: must be evaluated to ensure that the represented emissions reduction will occur continuously throughout the entire range of the facility’s normal operating conditions. On-Stream Time: goal of the proposed emission reduction option is to have it on-stream 100% of the time or to have a back-up emission reduction option. (Back-up emission reduction option must also meet established BACT for the specific type of control device.) Enforceability: proposed BACT performance demonstration methods must be evaluated. Performance demonstration methods can include recordkeeping, testing, and/or monitoring. On-stream Time Reliability

Eliminate technically infeasible options Rank remaining control options After ranking remaining control options, eliminate options on collateral impacts, and select BACT. Eliminate options on collateral impacts

Collateral Impacts Energy impacts – additional requirements
Emissions of air toxics Solid or hazardous waste generated Water discharge from controls Economic impacts - $/ton

Eliminate technically infeasible options Rank remaining control options After ranking remaining control options, eliminate options on collateral impacts and select BACT. Eliminate options on collateral impacts Select BACT

Top-Down method – negative aspects
Can be time consuming Adds to expense – must explore non- technically practicable control options If done thoroughly, it is very time consuming. Adds to expense since a number of control options will be explored that may have been previously demonstrated as not technically practicable.

Top-down example Tier II Example LAER Example Top-Down Example
Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy cfm = cubic feet per minute ppm = parts per million Each of the two coating lines at the plant consist of a stain booth, stain oven, sealer booth, sealer oven, topcoat booth, and ultra violet cure oven. The booths and ovens achieve 100% capture of emissions since the face velocity (intake velocity) across the openings exceeds 100 ft/min. There are no emissions from the parts after exiting the topcoat booth since a UV cure coating with no solvents is used. The intense UV radiation polymerizes the coating in the oven and no emissions from this portion of the process. Image of paperclip created by John Caserta from Noun Project.

Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy PSD review Attainment County PSD review is triggered since the site is a major source in an attainment county. A Top-Down BACT evaluation is required. Major Source

Control Options: Flare Carbon adsorption system Water based coatings Rotary concentrator Regenerative thermal oxidizer Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy PSD review

Inlet concentration is too low
Tier II Example Top-down example LAER Example Top-Down Example Control Options: Flare Carbon adsorption system Water based coatings Rotary concentrator Regenerative thermal oxidizer Eliminate technically infeasible options. Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy PSD review Inlet concentration is too low Eliminate technically infeasible options. Flare – Inlet concentration is too low.

VOC stream composition is variable
Tier II Example Top-down example LAER Example Top-Down Example Control Options: Flare Carbon adsorption system Water based coatings Rotary concentrator Regenerative thermal oxidizer Eliminate technically infeasible options. Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy PSD review VOC stream composition is variable Eliminate technically infeasible options. Flare – Inlet concentration is too low. Carbon adsorption system – VOC stream composition is variable.

Control Options: Flare Carbon adsorption system Water based coatings Rotary concentrator Regenerative thermal oxidizer Eliminate technically infeasible options. Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy PSD review Causes grain raising Eliminate technically infeasible options. Flare – Inlet concentration is too low. Carbon adsorption system – VOC stream composition is variable. Water based coatings – Causes grain raising.

Control Options: Flare Carbon adsorption system Water based coatings Rotary concentrator Regenerative thermal oxidizer Rank remaining control options. Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy PSD review Control efficiency = 94% Rank remaining control options. Rotary concentrator - control efficiency = 94% Regenerative thermal oxidizer - control efficiency = 98% Control efficiency = 98%

Insignificant except cost.
Top-Down Example Tier II Example Top-down example LAER Example Control Options: Flare Carbon adsorption system Water based coatings Rotary concentrator Regenerative thermal oxidizer Eliminate options. Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy PSD review Collateral impacts? Insignificant except cost. Collateral impacts? Collateral impacts? Collateral impacts are insignificant except cost ($/ton). A detailed cost analysis is completed.

This cost is reasonable.
Tier II Example Top-down example LAER Example Top-Down Example Cost analysis: Control Cost = $9,400/ ton Complete a detailed cost analysis. Control Options: Flare Carbon adsorption system Water based coatings Rotary concentrator Regenerative thermal oxidizer Eliminate options. Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy PSD review This cost is reasonable. Eliminate options – collateral impacts. Collateral impacts are insignificant except cost ($/ton). A detailed cost analysis is completed. Control cost is $9400/ton – This cost is reasonable. Select BACT. BACT = use of a 98% efficient regenerative thermal oxidizer (RTO).

Cost analysis: Control Cost = $9,400/ ton Complete a detailed cost analysis. Select BACT: Use of a 98% efficient RTO Control Options: Flare Carbon adsorption system Water based coatings Rotary concentrator Regenerative thermal oxidizer Eliminate options. Kitchen Cabinet Plant: In McLennan County Total airflow rate = 140,000 cfm VOC exhaust = 190 ppm Plant-wide VOC = 277 tpy PSD review Capture Efficiency: As noted above, the design of the ventilation system achieves 100% capture efficiency and would apply to any control option selected. Reliability: Both rotary concentrators and regenerative thermal oxidizers operate reliably with varying inlet concentrations and changes in coating formulations (solvents). On-Stream Time: Unless the unit goes offline for some unexpected reason, such as a power outage or an over temperature condition, both of these control devices have proven to be reliable as long as they are properly maintained. Enforceability: After an initial performance test to set the proper operating temperature to achieve the required level of reduction, combustion chamber temperatures are continuously monitored and recorded to demonstrate that the unit is operating in such a manner that the required reduction is continuously achieved. Select BACT: BACT = use of a 98% efficient RTO. Image of paperclip created by John Caserta from Noun Project.

? What is Laer? Most stringent level of control required under the Clean Air Act The most stringent emissions limitation, which is contained in the State Implementation Plan (SIP), for a class or source category, unless the owner or operator of the source demonstrates that such limitations are not achievable; or The most stringent emissions limitation that is achieved in practice by a class or source category. This limitation, when applied to a modification, means the lowest achievable emissions rate for the new or modified facilities. (Lowest achievable emission rate (LAER) means, for any source, the more stringent rate of emissions based on the following: The most stringent emissions limitation which is contained in the implementation plan of any state for such class or category of stationary source, unless the owner or operator of the proposed stationary source demonstrates that such limitations are not achievable; or The most stringent emissions limitation which is achieved in practice by such class or category of stationary sources. This limitation, when applied to a modification, means the lowest achievable emissions rate for the new or modified emissions units within or stationary source. In no event shall the application of the term permit a proposed new or modified stationary source to emit any pollutant in excess of the amount allowable under an applicable new source standard of performance.

Why do a laer evaluation?
When proposing construction of: A new major source; or A major modification to existing sources in an area already out of compliance with federal NAAQS

What contaminants are subject?
Most common in Texas is O3 ; VOC and NO2 are precursors that are subject to review. O3 = ozone NO2 = nitrogen dioxide

applicable pollutants
BACT Each regulated NSR pollutant LAER Criteria pollutants (or precursors where applicable) for nonattainment areas BACT: Each regulated NSR pollutant is applicable. LAER: Criteria pollutants (or precursors where applicable) for which the area is designated nonattainment are applicable.

Applicable Sources BACT
Any proposed major stationary source or major modification emitting a regulated air pollutant LAER Major source or major modification in a nonattainment area BACT: Applicable sources are any proposed major stationary source or major modification emitting a regulated air pollutant. LAER: Applicable sources are major source or major modification in a nonattainment area.

requirements BACT Emissions limit considering technical practicability and economic reasonableness LAER Emissions limitation contained in the SIP Most stringent limitation achieved in practice BACT: Requirements include emissions limit considering technical practicability and economic reasonableness. LAER: Requirements include 1) the emissions limitation contained in the SIP; and 2) the most stringent limitation achieved in practice.

LAER Question Can you consider economic reasonableness in the evaluation of LAER? No. LAER must be technically feasible, meaning something that has been achieved in practice; it is commercially available and actually been done.

To determine laer, Check
Recently approved Texas permits; Recently approved permits in other states; and All state SIPs; or The RBLC RBLC = RACT/BACT/LAER Clearinghouse

laer Follow up RBLC data is not always reliable due to incomplete data or errors in input. Obtain copies of permits to review data. Determine if the permitted project was built, and if it met the permit requirements. RBLC = RACT/BACT/LAER Clearinghouse

Laer example LAER Example Tier II Example Top-Down Example
300 MMBtu/hr Boiler: In Harris County VOC and NO2 precursors Net emission increase is significant NNSR is applicable Nonattainment for O3. Project MMBtu/hr Boiler in Harris county. Harris County is nonattainment for O3. VOC and NO2 precursors are emitted. Net emission increase demonstrated NNSR is applicable.

Applicant Proposal: Low NOx burners at 9 ppmvd 300 MMBtu/hr Boiler: In Harris County VOC and NO2 precursors Net emission increase is significant NNSR is applicable LAER analysis is required. Applicant proposes low NOx burners at 9 parts per million, by volume, dry basis (ppmvd).

Projects that did not trigger LAER
Laer example LAER Example Tier II Example Top-Down Example Projects that did not trigger LAER Applicant Proposal: Low NOx burners at 9 ppmvd Research Recently issued permits; RBLC search; Approved permits in other states; and Other state SIPs 300 MMBtu/hr Boiler: In Harris County VOC and NO2 precursors Net emission increase NNSR is applicable LAER analysis is required. Proposal is based on recently issued permits and RBLC search. Staff indicates this is not LAER: Recently issued permits were for projects that did not trigger LAER – they were based on a BACT analysis and additional controls were not considered due to cost.

Latest entry in RBLC is over 2 years old
Laer example LAER Example Tier II Example Top-Down Example Applicant Proposal: Low NOx burners at 9 ppmvd Research Recently issued permits; RBLC search; Approved permits in other states; and Other state SIPs 300 MMBtu/hr Boiler: In Harris County VOC and NO2 precursors Net emission increase NNSR is applicable LAER analysis is required. Latest entry in RBLC is over 2 years old Latest entry in RBLC is over two years old for this type of source. Is the RBLC up-to-date? Not all projects end up in the RBLC, and it is not always reliable.

California SIP reveals a
Laer example Tier II Example Top-Down Example LAER Example Applicant Proposal: Low NOx burners at 9 ppmvd Research Recently issued permits; RBLC search; Approved permits in other states; and Other state SIPs 300 MMBtu/hr Boiler: In Harris County VOC and NO2 precursors Net emission increase NNSR is applicable LAER analysis is required. Applicant Proposal: Low NOx burners at 9 ppmvd Research Recently issued permits; RBLC search; and Approved permits in other states (California SIP reveals a 5 ppmvd requirement). California SIP reveals a 5 ppmvd requirement A review of the California SIP reveals a 5 ppmvd requirement.

Established LAER: Low NOx burners at 5 ppmvd and addition of SCR. Applicant Proposal: Low NOx burners at 9ppmvd Research Recently issued permits; RBLC search; and Approved permits in other states 300 MMBtu/hr Boiler: In Harris County VOC and NO2 precursors Net emission increase NNSR is applicable LAER analysis is required. Applicant: “Unreasonably increases cost of control.” This level of control has been achieved practice through the use of low NOx burners and the use of selective catalytic reduction (SCR). The applicant states that the addition of SCR increases the cost of control directly and in terms of $/ton to an unreasonable level.

Established LAER: Low NOx burners at 5 ppmvd and addition of SCR. Cost is not a consideration in LAER analysis. Applicant Proposal: Low NOx burners at 9ppmvd Research Recently issued permits; RBLC search; and Approved permits in other states 300 MMBtu/hr Boiler: In Harris County VOC and NO2 precursors Net emission increase NNSR is applicable LAER analysis is required. Cost is not a consideration in a LAER analysis. LAER remains at 5 ppmvd. LAER remains at 5 ppmvd.

BACT also applies to: The remainder of the criteria pollutants. Individual species such as ammonia. Established LAER: Low NOx burners at 5 ppmvd and addition of SCR. Cost is not a consideration in LAER analysis. Applicant Proposal: Low NOx burners at 9ppmvd Research Recently issued permits; RBLC search; and Approved permits in other states 300 MMBtu/hr Boiler: In Harris County VOC and NO2 precursors Net emission increase NNSR is applicable LAER analysis is required. In addition to the LAER determination for NO2 for the boiler project- BACT (PSD) applies to the remainder of the criteria pollutants such as carbon monoxide (CO). BACT applies to individual species such as ammonia.

Air Permits Division (512) 239-1250
questions Thank you! Air Permits Division (512)

Concepts and Practical Application

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Concepts and Practical Application

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