Iowa Department of Natural Resources



Iowa Department of Natural Resources

Environmental Services Division

Air Quality Bureau

Prevention of Significant Deterioration (PSD) Permit Review

Technical Support Document for Issuance of PSD Permits for

Project Number 02-528, Plant Number 78-01-026

MidAmerican Energy Company

2115 Navajo Road

Council Bluffs, IA 51501

Table of Contents

|Section |Page |

|Purpose of this Document ………………………………………………………………………………. |5 |

|Introduction to the Project ……………………………………………………………………………… |5 |

|Introduction to New Source Review (NSR) and Prevention of Significant Deterioration (PSD) |6 |

|PSD Applicability …………………………………………………………………………………………. |7 |

|Analysis of the Application | |

|PSD …………………………………………………………………………………………………….. |8 |

|New Source Performance Standards (NSPS) …………………………………………………… |9 |

|National Emission Standards for Hazardous Air Pollutants (NESHAP) ……………………… |9 |

|Acid Rain ……………………………………………………………………………………………… |10 |

|Iowa Administrative Code (IAC) ………………………………………………………………….. |10 |

|Ambient Air Monitoring (Pre- and Post- Construction) …………………………………………….. |10 |

|Best Available Control Technology (BACT) ………………………………………………………….. |11 |

|CBEC Boiler 4 & Carbon Silos | |

|Particulate Matter (PM) ………………………………………………………………………. |11 |

|Fine Particulate Matter (PM10) ………………………………………………………………. |12 |

|Opacity …………………………………………………………………………………………… |12 |

|Nitrogen Oxides (NOx) ………………………………………………………………………… |12 |

|Sulfur Dioxide (SO2) …………………………………………………………………………… |13 |

|Carbon Monoxide (CO) ………………………………………………………………………. |14 |

|Volatile Organic Compounds (VOC) ..……………………………………………………….. |15 |

|Lead (Pb) ……………………………………………………………………………………….. |17 |

|Fluorides (F) ….………………………………………………………………………………….. |18 |

|Total Reduced Sulfur (TRS) ………………………………………………………………….. |18 |

|Sulfuric Acid Mist ………………………………………………………………………………. |18 |

|Auxiliary Boiler | |

|Particulate Matter (PM) ………………………………………………………………………. |19 |

|Fine Particulate Matter (PM10) ………………………………………………………………. |19 |

|Opacity ……………………………………………………………………………………………. |19 |

|Sulfur Dioxide (SO2) …………………………………………………………………………… |20 |

|Nitrogen Oxides (NOx) ………………………………………………………………………… |20 |

|Carbon Monoxide (CO) ………………………………………………………………………. |21 |

|Volatile Organic Compounds (VOC) ..……………………………………………………….. |21 |

|Lead (Pb) ……………………………………………………………………………………….. |21 |

|Emergency Generator ……………………………………………………………………………….. |21 |

|Particulate Matter (PM) ………………………………………………………………………. |22 |

|Fine Particulate Matter (PM10) ………………………………………………………………. |22 |

|Opacity ……………………………………………………………………………………………. |22 |

|Sulfur Dioxide (SO2) …………………………………………………………………………… |22 |

|Nitrogen Oxides (NOx) ………………………………………………………………………… |22 |

|Volatile Organic Compounds (VOC) ..……………………………………………………….. |22 |

|Carbon Monoxide (CO) ………………………………………………………………………. |22 |

|Diesel Fire Pump …………………………………………………………………………………….. |23 |

|Particulate Matter (PM) ………………………………………………………………………. |23 |

|Fine Particulate Matter (PM10) ………………………………………………………………. |23 |

|Opacity ……………………………………………………………………………………………. |23 |

|Sulfur Dioxide (SO2) …………………………………………………………………………… |23 |

|Nitrogen Oxides (NOx) ………………………………………………………………………… |23 |

|Volatile Organic Compounds (VOC) ..……………………………………………………….. |24 |

|Carbon Monoxide (CO) ………………………………………………………………………. |24 |

|Cooling Tower | |

|Particulate Matter (PM) ………………………………………………………………………. |24 |

|Fine Particulate Matter (PM10) ………………………………………………………………. |24 |

|Opacity …………………………………………………………………………………………… |25 |

|Coal & Flyash Handling Equipment (i.e. Silos, Vacuum Systems, etc.) | |

|Particulate Matter (PM) ………………………………………………………………………. |25 |

|Fine Particulate Matter (PM10) ………………………………………………………………. |25 |

|Opacity …………………………………………………………………………………………… |26 |

|Lime Filter Separator, Lime Storage Silo, and Urea Silos | |

|Particulate Matter (PM) ………………………………………………………………………. |26 |

|Fine Particulate Matter (PM10) ………………………………………………………………. |26 |

|Opacity ……………………………………………………………………………………………. |27 |

|Fugitive Emissions …………………………………………………………………………………… |27 |

|Stacker conveyor ……………………………………………………………………………….. |27 |

|Transfer to active pile ………………………………………………………………………….. |27 |

|Bucket reclaim …………………………………………………………………………………… |27 |

|Rail unloading ……………………………………………………………………………………. |27 |

|Paved haul roads ……………………………………………………………………………….. |27 |

|Unpaved haul roads ……………………………………………………………………………. |27 |

|Active coal pile ………………………………………………………………………………….. |28 |

|Inactive coal pile ………………………………………………………………………………… |28 |

|Rail unloading coal stockout pile …………………………………………………………….. |28 |

|PSD Ambient Air Quality Analysis …………………………………………………………………….. |28 |

|PSD Increment ……………………………………………………………………………………….. |29 |

|NAAQS ………………………………………………………………………………………………… |31 |

|Wilderness and Parkland Protection …………………………………………………………………… |32 |

|Impact on Vegetation, Soils, and Visibility | |

|Soils & Vegetation …………………………………………………………………………………… |32 |

|Visibility ……………………………………………………………………………………………….. |32 |

|Impacts of Associated Growth on Air Quality ………………………………………………………. |34 |

|Requirements of PSD Public Notice …………………………………………………………………… |34 |

|112g (Case-by-Case MACT) Determination | |

|Introduction …………………………………………………………………………………………… |35 |

|Emergency generator analysis ..…………………………………………………………………… |37 |

|Fire pump analysis …………………………………………………………………………………… |38 |

|Auxiliary boiler analysis …………………………………………………………………………….. |38 |

|Boiler 4 analysis | |

|Organic Hazardous Air Pollutants (HAP) ……………………………………………………. |41 |

|Non-Mercury Metals . …………………………………………………………………………. |41 |

|Acid Gases ….. …………………………………………………………………………………. |42 |

|Mercury (Hg) ……………………………………………………………………………………. |43 |

|Compliance Testing | |

|CBEC Boiler 4 & Carbon Silos…………………………………………………………………. |46 |

|Auxiliary Boiler ……. . …………………………………………………………………………. |46 |

|Emergency Generator ….………………………………………………………………………. |46 |

|Diesel Fire Pump ..………………………………………………………………………………. |46 |

|Cooling Tower …. ………………………………………………………………………………. |46 |

|Coal & Flyash Handling Equipment .…………………………………………………………. |47 |

|Lime Filter Separator, Lime Storage Silo, and Urea Silos ..………………………………. |47 |

|Fugitive Emissions ………………………………………………………………………………. |47 |

|Department Determination …………………………………………………………………… |47 |

|Supporting References to the Administrative Record ……………………………………. |49 |

Purpose of this Document

This document has been prepared to fulfill the public participation requirements of 567 Iowa Administrative Code (IAC) 22.2(2), 567 IAC 22.4, 40 Code of Federal Regulations (CFR) 51.166, and 40 CFR 124.

Introduction to the Project

MidAmerican Energy (MidAmerican) currently operates the Council Bluffs Energy Center (CBEC) site located south of Council Bluffs in Pottawattamie County, Iowa. The plant currently consists of three (3) coal-fired electric generating units with a combined net generation capacity of 821 Megawatts (MW). The CBEC facility is considered a major source for Prevention of Significant Deterioration (PSD) purposes. MidAmerican has applied to the Iowa Department of Natural Resources (IDNR) for PSD permits for a “major modification” to the CBEC plant.

The major modification consists of adding one (1) new coal-fired boiler (790 net MW), modifying existing coal handling equipment, and adding additional ancillary equipment (i.e. coal handling, fly ash handling, auxiliary boiler, fire pump, emergency generator, etc.). The equipment associated with this project is:

• Rotary Car Dumper (existing unit to be modified)

• Transfer House 2 (existing unit to be modified)

• Transfer House 4 (existing unit to be modified)

• CBEC 4 Boiler

• Three (3) Carbon Silos

• Auxiliary Boiler

• Emergency Generator

• Diesel Fire Pump

• Cooling Tower

• Transfer Conveying Bay

• Three (3) Unit 4 East Silos

• Three (3) Unit 4 West Silos

• Lime Filter Separator

• Lime Storage Silo

• Two (2) Urea Silos

• Flyash and Flue Gas Desulfurization Waste Storage Silo

• Three (3) Flyash and Flue Gas Desulfurization Vacuum Systems

• Fugitive emissions (i.e. haul roads, coal storage piles, and transfer points)

The proposed Unit 4 boiler will be an indoor-type supercritical pulverized coal fired boiler designed for “base load” operation. The primary fuel of CBEC 4 will be Powder River Basin sub-bituminous coal with a maximum sulfur content of 0.625 lb of S/MMBTU. The coal will be delivered to the plant by rail and in trucks. The unit will have a maximum gross heat input of about 7,675 MMBTU/hr and 67.23 x 106 MMBTU/yr. Number 2 fuel oil will be used in CBEC 4 for light off, startup, and flame stabilization. The fuel oil is stored in an existing above ground tank that currently serves Unit 3. The amount of oil burned per year will be approximately 800,000 gallons total between Units 3 & 4.

The application for this project was received on September 25, 2002. The public comment period for the draft permits will run from April 28, 2003 to May 28, 2003.

Introduction to New Source Review (NSR) and Prevention of Significant Deterioration (PSD)

On August 7, 1977 Congress substantially amended the Clean Air Act (CAA or the Act). These amendments added detailed PSD and nonattainment area (NAA) programs. On June 19, 1978 the United States Environmental Protection Agency (USEPA) revised the PSD regulations to comply with the 1977 amendments. The June 1978 regulations were challenged in court and as a result of the judicial review on August 7, 1980 EPA extensively revised both the PSD (for attainment areas) and NAA (for nonattainment areas) regulations. Five sets of regulations resulted from those revisions. These regulations, subsequent modifications, USEPA guidance documents, interpretations, and policies represent the current NSR regulatory requirements.

The first set of regulations, 40 CFR 51.166, specifies the minimum requirements that a PSD air quality permit program under Part C of the Act must contain in order to obtain approval by EPA as a revision to a State Implementation Plan (SIP). The second set, 40 CFR 52.21, delineates the federal PSD permit program which currently applies as part of the SIP for States that have not submitted a PSD program meeting the requirements of 40 CFR 51.166. Roughly two thirds of the States are implementing their own PSD programs which have been approved by EPA under 40 CFR 51.166. Iowa is implementing its own PSD program. 40 CFR 52.21 applies in the remaining States. The remainder of the five regulations applies to the NAA program.

The basic goals of the PSD regulations are:

1) to ensure that economic growth will occur in harmony with the preservation of existing clean air resources

2) to protect the public health and welfare from any adverse effects which might occur even though air pollution concentrations are below the National Ambient Air Quality Standards (NAAQS)

3) to preserve, protect, and enhance the air quality in areas of special natural recreational, scenic, or historic value, such as national parks and wilderness areas

4) to provide the opportunity for public comment on proposed applications

The PSD regulations require that "major modifications" be reviewed prior to construction to ensure compliance with the NAAQS, PSD increment consumption, and Best Available Control Technology (BACT) as well as all other PSD requirements.

To qualify for PSD review, sources must be located in a region designated as "attainment" or “unclassifiable” for any pollutant(s) emitted by the source in "PSD significant" quantities. Emissions from the source must be greater than the "major stationary source" threshold. A "major stationary source" is defined in Section 169 of the CAA as:

Any one of 28 types of sources with the potential-to-emit 100 tons per year or more of any pollutant regulated in the CAA or any other type of source with the potential to emit regulated pollutants in amounts equal to or greater than 250 tons per year.

All PSD thresholds are based upon "potential-to-emit (PTE)." For PSD applicability purposes only, this is the maximum design capacity of a stationary source to emit a pollutant under its physical and operational design after the application of air pollution control equipment and after considering all "federally enforceable" limitations restricting the potential-to-emit of the source.

PSD regions are defined as Class I through Class III. Class I areas are international parks, national wilderness areas and national memorial parks greater than 5,000 acres in size and national parks which exceed 6,000 acres in size. Class II areas include all areas not designated as Class I or Class III. Area classifications affect the maximum allowable increase in the PSD ambient air increments with Class I areas allowed the least increase and Class III areas allowed the most. All of the State of Iowa is classified as a Class II area. There are no Class III areas in existence in the United States.

PSD Applicability

MidAmerican qualifies as one of the 28 major source categories because it is a Fossil fuel-fired steam electric plant with more than 250 million British thermal units (MMBTU) per hour of heat input. Therefore, the MidAmerican plant at 2115 Navajo Road, Council Bluffs, Iowa is classified as a "major stationary source" for PSD purposes due to potential emissions greater than 100 tons per year of any one of the pollutants regulated by the CAA. In addition, fugitive emissions, to the extent quantifiable, are considered in any subsequent PSD analysis.

The following tables show the potential emissions increases for the new equipment proposed in project number 02-528:

TABLE 1 – POTENTIAL EMISSIONS FOR THE PROJECT (W/O BACT LIMITS)

| |BASELINE |EMISSION |PSD SIGNIFICANCE |

|POLLUTANT |EMISSIONS (TPY) |INCREASE (TPY) |LEVEL (TPY) |

|PM |1,607.7 |3653.6 |25 |

|PM10 |966.8 |3653.6 |15 |

|SO2 |20,805.2 |4,034.5 |40 |

|NOx |13,684.5 |6,324.3 |40 |

|CO |885.8 |8,659.5 |100 |

|VOC |108.7 |129.7 |40 |

|Lead (Pb) |0.7 |17.0 |0.6 |

|Fluorides |139.9 |303 |3 |

|Sulfuric Acid Mist |0.0 |1,416 |7 |

|Total Reduced Sulfur (TRS) |0.0 |297 |10 |

TABLE 2 – POTENTIAL EMISSIONS OF PROJECT (W/ BACT LIMITS)

|POLLUTANT |EMISSION INCREASE (TPY) |

|PM |611.0 |

|PM10 |809.9 |

|SO2 |3,362.0 |

|NOx |2,389.3 |

|CO |5,196.5 |

|VOC |122.7 |

|Pb |0.9 |

|Fluorides |30.3 |

|Sulfuric Acid Mist |141.6 |

|Total Reduced Sulfur (TRS) |29.7 |

Analysis of the Application

A. PSD: The source is classified as a "major stationary source" for PSD purposes. Therefore, the PSD process must be followed for all pollutants for which emissions will be increased equal to or greater than the PSD significance levels. PM, PM10, SO2, NOx, CO, VOC, Pb, Fluorides, TRS, and sulfuric acid mist all exceed their respective significance levels. No source subject to PSD review may be constructed without a PSD permit. To obtain a PSD permit the applicant must:

1) Conduct a BACT analysis, on a case-by-case basis, in which energy, environmental and economic impacts are considered in determining the maximum degree of reduction of emissions that are achievable for the proposed unit.

2) Perform an analysis of the ambient air quality prior to the major modification (i.e. preconstruction monitoring).

3) Demonstrate that the modified emissions from the proposed project and associated growth due to the project will not exceed the NAAQS or applicable PSD increments.

4) Perform additional analysis on the effects of the modified emissions on soils, vegetation, and visibility.

5) Address the air quality impacts of associated growth in the area of the source since the minor source baseline date and of major sources in the area since the major source baseline date.

6) Demonstrate that the modification will not adversely impact a Class I area.

In addition, the public must be notified of the proposed project, the degree of the increment consumption, and be given the opportunity for submitting written comments. The IDNR will hold a public opportunity for persons to comment on the project in person.

B. New Source Performance Standards (NSPS): The following NSPS subparts are applicable to this project:

1. 40 CFR §60.1 - 40 CFR §60.19, Subpart A (General Provisions): This subpart affects any facility that is subject to any NSPS subpart.

2. 40 CFR §60.40a - 40 CFR §60.49a, Subpart Da (Standards of Performance for Electric Utility Steam Generating Units for Which Construction is Commenced After September 18, 1978): This subpart affects any fossil-fuel-fired steam generating unit of more than 73 megawatts heat input rate (250 MMBTU/hr) that commences construction or modification after September 18, 1978. The subpart sets the following standards on the exhaust gases:

a) Cannot contain particulate matter in excess of 0.03 lb/MMBTU.

b) Exhibit greater than 20 percent opacity, except for one (1) six (6) minute period per hour.

c) Cannot contain SO2 in excess of 1.2 lb/MMBTU.

d) 90% SO2 reduction (or 70% reduction if emissions are less than 0.60 lb/MMBTU)

e) Cannot contain NOx in excess of 200 ng/J gross energy output (1.6 lb/Megawatt hour gross energy output).

3. 40 CFR §60.40b - 40 CFR §60.49b, Subpart Db (Standards of Performance for Industrial-Commercial-Institutional Steam Generating Units): This subpart affects each steam generating unit that commences construction, modification, or reconstruction after June 19, 1984 and that has a heat input capacity from fuels combusted in the steam generating unit of greater than 29 MW (100 MMBTU/hr). Since the facility is limiting the use of the auxiliary boiler to natural gas only and a 10% capacity factor the subpart sets the following standards on the exhaust gases:

a) NOx limits for low and high release rates. See 40 CFR §60.44b for these standards.

4. 40 CFR §60.250 - 40 CFR §60.254, Subpart Y (Standards of Performance for Coal Preparation Plant): This subpart affects certain processes at a coal preparation plant which processes more than 181 Mg (200 tons) per day and commences construction or modification after October 24, 1974. The subpart sets the following standards on the exhaust gases:

a) Cannot exhibit opacity 20% or greater.

C. National Emission Standards for Hazardous Air Pollutants (NESHAP): The following NESHAP subparts are applicable to this project:

1. 40 CFR §63.1 - 40 CFR §63.15, Subpart A (General Provisions): This subpart affects any facility that is subject to any NESHAP subpart.

2. 40 CFR §63.40 - 40 CFR §63.56, Subpart B [Requirements for Control Technology Determination for Major Sources in Accordance With Clean Air Act Sections, Sections 112(g) and 112(j)]: This subpart requires a Case-by-Case MACT determination for those source categories for which a NESHAP has not been promulgated.

D. Acid Rain: The facility is considered an affected source under 40 CFR 72, 73, 75, 76, 77, and 78 definitions as emission units at the source are subject to the acid rain emission reduction requirements or the acid rain emission limitations, as adopted by the Department by reference (See 567 IAC 22.120 – 567 IAC 22.148). CBEC Boiler 4 will be subject to the SO2 allowance allocation, NOx emission limitations, and monitoring provisions of the federal acid rain program.

E. Iowa Administrative Code (IAC): The following sections of the IAC are applicable to the proposed project:

1. 567 IAC 21.5: Evidence used in establishing that a violation has or is occurring.

2. 567 IAC 22.1(1): Permit required. Requirement for new or modified equipment to obtain a construction permit.

3. 567 IAC 22.4: Special requirements for major stationary sources located in areas designated attainment or unclassified (PSD). State adoption of the PSD regulations.

4. 567 IAC 22.120 – 567 IAC 22.148: Acid Rain program. State references to the Acid Rain program.

5. 567 IAC 23.1(2)”v”: Coal preparation plants. State reference to NSPS Subpart Y.

6. 567 IAC 23.1(2)”z”: Electric utility steam generating units. State reference to NSPS Subpart Da.

7. 567 IAC 23.1(2)”ccc”: Industrial-commercial-institutional steam generating units. State reference to NSPS Subpart Db.

8. 567 IAC 23.1(4)”b”(1): Section 112(g) requirements. State reference to NESHAP Subpart B.

Ambient Air Monitoring (Pre- and Post- Construction)

40 CFR §52.21(m) requires preconstruction ambient air monitoring for any pollutant in which the applicant proposes to emit in significant amounts. If, however, either the predicted ambient impact caused by the emissions increase or the existing ambient air concentrations are less than the prescribed significant monitoring value [See 40 CFR §52.21(i)(8)], the permitting agency has discretionary authority to exempt an applicant from this data requirement.

All pollutants except for PM10 and SO2 were below their respective significant monitoring value. Therefore, the Department has waived both pre-and post-construction monitoring for those pollutants.

In the case of PM10, MidAmerican had stated in its draft and final modeling protocol that the preliminary PM10 modeling indicated the project’s impacts would be below the PSD pre-application monitoring de minimus level of 10 ug/m3, thus eliminating the need for pre-application monitoring for PM10. However, the application shows the predicted impacts are over the PSD pre-application monitoring de minimus level. In addition, the preliminary analysis using EPA’s Air Data Web site indicate the 95th percentile of the monitored PM10 concentration in the Council Bluffs area were also over the PSD pre-application monitoring de minimus level (See memo of April 25, 2003 from Lori Hanson to Chris Roling). Pre-construction monitoring was waived. However, the Department is requiring a minimum of one (1) year of post-construction monitoring.

MidAmerican contacted the Department in April of 2002 concerning SO2 monitoring. Based on existing monitors in the Omaha area the Department waived pre-construction monitoring (See memo of April 19, 2002 from Jim McGraw and Sean Fitzsimmons to Chris Roling). However, the Department is requiring a minimum of one (1) year of post-construction monitoring.

Best Available Control Technology (BACT)

BACT is an emission limit, associated control technology, and efficiency based on the maximum degree of pollution reduction which the IDNR determines is achievable taking into account energy, environmental, economic, and other factors. All new major stationary sources and all major modifications must conduct an analysis to ensure that BACT is specified for each pollutant that exceeds the PSD "significant" thresholds. Each BACT analysis is conducted on a case-by-case basis. The economic analysis is conducted using costs that are valid for that area in which the source is located. No technology may be approved which is less stringent that the NSPS found in 40 CFR 60 [See also 567 IAC 23.1(2)] or any of the NESHAPS found in 40 CFR 61 [See also 567 IAC 23.1(3)].

To fulfill PSD requirements, the applicant has performed a BACT analysis for the new & modified equipment for each pollutant emitted above the PSD "significance level." Following is a summary of the BACT determinations for each pollutant and each piece of equipment:

CBEC Boiler 4 & Carbon Silos:

Particulate Matter (PM):

Baghouse: This technology removes particulate from the flue gas by drawing the dust-laden air through a bank of filter tubes suspended in a housing. The filter cake builds up on the outside of a tubular bag and periodically either a pulsejet of air or a shaker mechanism is used to force the filter cake to fall. The dust is then collected in a hopper and removed. A baghouse is considered the most effective control for the removal of particulate matter. MidAmerican is proposing to use a baghouse on these emission units for control of particulate. In accordance with EPA guidance no other control options need be considered when the highest efficiency control device is selected as the most effective control.

BACT for the project: Baghouse

Emission Rate: 0.027 lb/MMBTU (average of 3 stack test runs). Please note that this limit is for front & back-half particulate (filterable & condensible) matter.

Fine Particulate Matter (PM10):

Baghouse: This technology removes particulate from the flue gas by drawing the dust-laden air through a bank of filter tubes suspended in a housing. The filter cake builds up on the outside of a tubular bag and periodically either a pulsejet of air or a shaker mechanism is used to force the filter cake to fall. The dust is then collected in a hopper and removed. A baghouse is considered the most effective control for the removal of particulate matter. MidAmerican is proposing to use a baghouse on these emission units for control of particulate. In accordance with EPA guidance no other control options need be considered when the highest efficiency control device is selected as the most effective control.

BACT for the project: Baghouse

Emission Rate: 0.025 lb/MMBTU (average of 3 stack test runs). Please note that this limit is for front & back-half particulate (filterable & condensible) matter.

Opacity:

According to 40 CFR §52.21(b)(12), BACT includes an emission limitation for visible emissions. Since in most cases particulate matter is the main cause of visible emissions the opacity BACT limit is based on the level of emissions expected from the particulate control equipment. Since BACT for PM & PM10 are to met by a baghouse the following emission rate is considered BACT:

Emission Rate: 5% (1-hr average)

Nitrogen Oxides (NOx):

Selective Catalytic Reduction (SCR): Catalyst bed installed between economizer and combustion air preheater in a conventional power plant. The temperature range of the flue gas at this point is between 650-750F. Ammonia is injected into the flue gas stream and catalytically reduces the NOx to nitrogen and water. Reductions of 80 to 90 percent could be seen from this technology. SCR is considered the most effective control at the removal of NOx emissions. MidAmerican is proposing to use SCR in combination with Low NOx burners (see description below) and overfire air for control of NOx. In accordance with EPA guidance no other control options need be considered when the highest efficiency control device is selected as the most effective control.

Low NOx burners: Burner design – designed to combust fuel in a sub-stoichiometric mode (i.e., air: fuel ratio ................
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