AIR EMISSION PERMIT NO IS ISSUED TO. Minnesota Power Division of ALLETE Inc

Transcription

1 AIR EMISSION PERMIT NO IS ISSUED TO Minnesota Power Division of ALLETE Inc MINNESOTA POWER - LASKIN ENERGY CENTER 5699 Colby Lake Road Hoyt Lakes, St. Louis County, MN The emission units, control equipment and emission stacks at the stationary source authorized in this permit are as described in the following permit application(s): Permit Type Application Date Total Facility Reissuance 11/14/2001 Supplemental Information No. 1 7/11/2008 Supplemental Information No. 2 8/26/2008 Administrative Amendment 4/6/2007 Administrative Amendment 5/30/2008 This permit supersedes Air Emission Permit No and authorizes the Permittee to operate the stationary source at the address listed above unless otherwise noted in Table A. The Permittee must comply with all the conditions of the permit. Any changes or modifications to the stationary source must be performed in compliance with Minn. R to Terms used in the permit are as defined in the state air pollution control rules unless the term is explicitly defined in the permit. Permit Type: Federal; Pt 70/Major for NSR Issue Date: November 25, 2008 Expiration: November 25, 2013 All Title I Conditions do not expire. Don Smith, P.E. Manager Air Quality Permits Section Industrial Division for Brad Moore Commissioner Minnesota Pollution Control Agency TDD (for hearing and speech impaired only): (651) Printed on recycled paper containing at least 10% fibers from paper recycled by consumers

2 TABLE OF CONTENTS Notice to the Permittee Permit Shield Facility Description Table A: Limits and Other Requirements Table B: Submittals Table C: not used in this permit Appendix A: not used in this permit Appendix B: Acid Rain Permit Application Appendix C: Insignificant Activities Required to be Listed Appendix D: Compliance Assurance Monitoring Plan Appendix E: SO 2 Modeling Parameters Appendix F: NO X and PM 10 Modeling Parameters

3 NOTICE TO THE PERMITTEE: Your stationary source may be subject to the requirements of the Minnesota Pollution Control Agency s (MPCA) solid waste, hazardous waste, and water quality programs. If you wish to obtain information on these programs, including information on obtaining any required permits, please contact the MPCA general information number at: Metro Area Outside Metro Area TTY The rules governing these programs are contained in Minn. R. chs Written questions may be sent to: Minnesota Pollution Control Agency, 520 Lafayette Road North,St. Paul, Minnesota Questions about this air emission permit or about air quality requirements can also be directed to the telephone numbers and address listed above. PERMIT SHIELD: Subject to the limitations in Minn. R , compliance with the conditions of this permit shall be deemed compliance with the specific provision of the applicable requirement identified in the permit as the basis of each condition. Subject to the limitations of Minn. R and , subp. 2, notwithstanding the conditions of this permit specifying compliance practices for applicable requirements, any person (including the Permittee) may also use other credible evidence to establish compliance or noncompliance with applicable requirements. FACILITY DESCRIPTION: The Laskin Energy Center is an electric generating facility located near Aurora, Minnesota. This electric power facility contains two identical steam generating boilers, coal receiving, handling, and storage facilities, and ash handling and storage capabilities. Each boiler has twelve 4 mmbtu/hr natural gas/oilfired ignitors and dry low Nitrogen Oxides (NO X )combustors. Each boiler vents emissions to a highefficiency wet scrubber that discharges to the atmosphere through a common stack. The scrubbers control Particulate Matter (PM), Particulate matter smaller than 10 microns (PM 10 ), Sulfur dioxide (SO 2 ), and lead. The net generating capacity is 110 megawatts.

4 TABLE A: LIMITS AND OTHER REQUIREMENTS A-1 11/25/08 Facility Name: Permit Number: Minnesota Power - Laskin Energy Center Table A contains limits and other requirements with which your facility must comply. The limits are located in the first column of the table (What To do). The limits can be emission limits or operational limits. This column also contains the actions that you must take and the records you must keep to show that you are complying with the limits. The second column of Table A (Why to do it) lists the regulatory basis for these limits. Appendices included as conditions of your permit are listed in Table A under total facility requirements. Subject Item: Total Facility MODELING REQUIREMENTS What to do hdr Why to do it Parameters Used in Modeling: The parameters used in the modeling performed for determining emission and/or operational limits for this facility are listed in Appendix E of this permit. If the Permittee intends to change any of these parameters, the Permittee must submit the revised parameters to the Commissioner and receive written approval before making any changes. The revised parameter information submittal must include, but is not limited to: the locations, heights and diameters of the stacks; locations and dimensions of nearby buildings; velocity and temperatures of the gases emitted; and the emission rates. The plume dispersion characteristics due to the parameter revisions must equal or exceed the dispersion characteristics modeled for this permit, and the Permittee shall demonstrate this in the proposal. If the information does not demonstrate equivalent or better dispersion characteristics, or if a conclusion cannot readily be made about the dispersion, the Permittee must remodel. Parameters Used in Modeling (continued): For changes that do not involve an increase in an emission rate and that do not require a permit amendment, the proposal must be submitted as soon as practicable, but no less than 60 days before making the change to any parameter. For changes involving increases in emission rates and that require a minor permit amendment, the proposal must be submitted as soon as practicable, but no less than 60 days before making the change to any parameter. For changes involving increases in emission rates and that require a permit amendment other than a minor amendment, the proposal must be submitted prior to or with the permit amendment application. Minn. Stat. Section , subds. 4a & 9; Minn. R , subps 7A, 7L & 7M; Minn. R , subps. 1, 2 & 4; Minn. R CONTINUED CONTINUED This is a state only requirement and is not enforceable by the EPA Administrator and citizens under the Clean Air Act. DETERMINING IF A PROJECT/MODIFICATION IS SUBJECT TO NEW SOURCE REVIEW These requirements apply where there is a reasonable possibility (as defined in 40 CFR Section 52.21(r)(6)(vi)) that a proposed project, analyzed using the actual-to-projected-actual (ATPA) test (either by itself or as part of the hybrid test described in Section 52.21(a)(2)(iv)(f)) and found to not be part of a major modification, may result in a significant emissions increase. If the ATPA test is not used for a particular project, or if there is not a reasonable possibility that the proposed project could result in a significant emissions increase, then these requirements do not apply to that project. Even though a particular modification is not subject to New Source Review, or where there isn't a reasonable possibility that a proposed project could result in a significant emissions increase, a permit amendment, recordkeeping, or notification may still be required under Minn. R Preconstruction Documentation -- Before beginning actual construction on a project, the Permittee shall document the following: 1. Project description 2. Identification of any emission unit (EU) whose emissions of an NSR pollutant could be affected 3. Pre-change potential emissions of any affected existing EU, and the projected post-change potential emissions of any affected existing or new EU. 4. A description of the applicability test used to determine that the project is not a major modification for any regulated NSR pollutant, including the baseline actual emissions, the projected actual emissions, the amount of emissions excluded due to increases not associated with the modification and that the EU could have accommodated during the baseline period, an explanation of why the amounts were excluded, and any creditable contemporaneous increases and decreases that were considered in the determination. hdr Title I Condition: 40 CFR Section 52.21(r)(6); Minn. R ; Minn. R , subp. 2 Title I Condition: 40 CFR Section 52.21(r)(6); Minn. R ; Minn. R , subp. 4; Minn. R , subps. 4 & 5 The Permittee shall maintain records of this documentation.

5 TABLE A: LIMITS AND OTHER REQUIREMENTS A-2 11/25/08 Facility Name: Permit Number: Minnesota Power - Laskin Energy Center The Permittee shall monitor the actual emissions of any regulated NSR pollutant that could increase as a result of the project and that were analyzed using the ATPA test, and the potential emissions of any regulated NSR pollutant that could increase as a result of the project and that were analyzed using potential emissions in the hybrid test. The Permittee shall calculate and maintain a record of the sum of the actual and potential (if the hybrid test was used in the analysis) emissions of the regulated pollutant, in tons per year on a calendar year basis, for a period of 5 years following resumption of regular operations after the change, or for a period of 10 years following resumption of regular operations after the change if the project increases the design capacity of or potential to emit of any unit associated with the project. Before beginning actual construction of any project which includes any electric utility steam generating unit (EUSGU), the Permittee shall submit a copy of the preconstruction documentation (items 1-4 under Preconstruction Documentation, above) to the Agency. For any project which includes any EUSGU, the Permittee must submit an annual report to the Agency, within 60 days after the end of the calendar year. The report shall contain: Title I Condition: 40 CFR Section 52.21(r)(6); Minn. R ; Minn. R , subps. 4 & 5 Title I Condition: 40 CFR Section 52.21(r)(6)(ii); Minn. R ; Minn. R , subps. 4 & 5 Title I Condition: 40 CFR Section 52.21(r)(6); Minn. R ; Minn. R , subps. 4 & 5 a. The name and ID number of the facility, and the name and telephone number of the facility contact person b. The quantified annual emissions analyzed using the ATPA test, plus the potential emissions associated with the same project analyzed as part of a hybrid test. c. Any other information, such as an explanation as to why the summed emissions differ from the preconstruction projection, if that is the case. For any project which does not include any EUSGU, the Permittee must submit a report to the Agency if the annual summed (actual, plus potential used in hybrid test) emissions differ from the preconstruction projection and exceed the baseline actual emissions by a significant amount as listed at 40 CFR Section 52.21(b)(23). Such report shall be submitted to the Agency within 60 days after the end of the year in which the exceedances occur. The report shall contain: a. The name and ID number of the facility, and the name and telephone number of the facility contact person b. The annual emissions (actual, plus potential if any part of the project was analyzed using the hybrid test) for each pollutant for which the preconstruction projection and significant emissions rate is exceeded. c. Any other information, such as an explanation as to why the summed emissions differ from the preconstruction projection. OPERATIONAL REQUIREMENTS Title I Condition: 40 CFR Section 52.21(r)(6); Minn. R ; Minn. R , subps. 4 & 5 hdr The Permittee shall comply with National Primary and Secondary Ambient Air Quality Standards, 40 CFR pt. 50, and the Minnesota Ambient Air Quality Standards, Minn. R to Compliance shall be demonstrated upon written request by the MPCA. Circumvention: Do not install or use a device or means that conceals or dilutes emissions, which would otherwise violate a federal or state air pollution control rule, without reducing the total amount of pollutant emitted. Air Pollution Control Equipment: Operate all pollution control equipment whenever the corresponding process equipment and emission units are operated, unless otherwise noted in Table A. Operation and Maintenance Plan: Retain at the stationary source an operation and maintenance plan for all air pollution control equipment. At a minimum, the O & M plan shall identify all air pollution control equipment and control practices and shall include a preventative maintenance program for the equipment and practices, a description of (the minimum but not necessarily the only) corrective actions to be taken to restore the equipment and practices to proper operation to meet applicable permit conditions, a description of the employee training program for proper operation and maintenance of the control equipment and practices, and the records kept to demonstrate plan implementation. Operation Changes: In any shutdown, breakdown, or deviation the Permittee shall immediately take all practical steps to modify operations to reduce the emission of any regulated air pollutant. The Commissioner may require feasible and practical modifications in the operation to reduce emissions of air pollutants. No emissions units that have an unreasonable shutdown or breakdown frequency of process or control equipment shall be permitted to operate. Fugitive Emissions: Do not cause or permit the handling, use, transporting, or storage of any material in a manner which may allow avoidable amounts of particulate matter to become airborne. Comply with all other requirements listed in Minn. R CFR pt. 50; Minn. Stat. Section , subds. 4a & 9; Minn. R , subps. 7A, 7L & 7M; Minn. R , subps. 1, 2 & 4; Minn. R Minn. R Minn. R , subp. 2; Minn. R , subp. 16(J) Minn. R , subps. 14 and 16(J) Minn. R , subp. 4 Minn. R

6 TABLE A: LIMITS AND OTHER REQUIREMENTS A-3 11/25/08 Facility Name: Minnesota Power - Laskin Energy Center Permit Number: Noise: The Permittee shall comply with the noise standards set forth in Minn. R to at all times during the operation of any emission units. This is a state only requirement and is not enforceable by the EPA Administrator or citizens under the Clean Air Act. Inspections: The Permittee shall comply with the inspection procedures and requirements as found in Minn. R , subp. 9(A). The Permittee shall comply with the General Conditions listed in Minn. R , subp. 16. PERFORMANCE TESTING Performance Testing: Conduct all performance tests in accordance with Minn. R. ch unless otherwise noted in Tables A, B, and/or C. Performance Test Notifications and Submittals: Performance Tests are due as outlined in Tables A and B of the permit. See Table B for additional testing requirements. Minn. R Minn. R , subp. 9(A) Minn. R , subp. 16 hdr Minn. R. ch Minn. Rs , subp. 1-4, and Minn. R , subp. 1-2 Performance Test Notification (written): due 30 days before each Performance Test Performance Test Plan: due 30 days before each Performance Test Performance Test Pre-test Meeting: due 7 days before each Performance Test Performance Test Report: due 45 days after each Performance Test Performance Test Report - Microfiche Copy: due 105 days after each Performance Test The Notification, Test Plan, and Test Report may be submitted in alternative format as allowed by Minn. R Limits set as a result of a performance test (conducted before or after permit issuance) apply until superseded as stated in the MPCA's Notice of Compliance letter granting preliminary approval. Preliminary approval is based on formal review of a subsequent performance test on the same unit as specified by Minn. R , subp. 3. The limit is final upon issuance of a permit amendment incorporating the change. MONITORING REQUIREMENTS Monitoring Equipment Calibration: Annually calibrate all required monitoring equipment (any requirements applying to continuous emission monitors are listed separately in this permit). Operation of Monitoring Equipment: Unless otherwise noted in Tables A, B, and/or C, monitoring a process or control equipment connected to that process is not necessary during periods when the process is shutdown, or during checks of the monitoring systems, such as calibration checks and zero and span adjustments. If monitoring records are required, they should reflect any such periods of process shutdown or checks of the monitoring system. RECORDKEEPING Minn. R , subp. 3 hdr Minn. R , subp. 4(D) Minn. R , subp. 4(D) hdr Recordkeeping: Retain all records at the stationary source for a period of five (5) years from the date of monitoring, sample, measurement, or report. Records which must be retained at this location include all calibration and maintenance records, all original recordings for continuous monitoring instrumentation, and copies of all reports required by the permit. Records must conform to the requirements listed in Minn. R , subp. 5(A). Recordkeeping: Maintain records describing any insignificant modifications (as required by Minn. R , subp. 3) or changes contravening permit terms (as required by Minn. R , subp. 2), including records of the emissions resulting from those changes. When the Permittee determines that no permit amendment or notification is required prior to making a change, the Permittee must retain records of all calculations required under Minn. R For expiring permits, these records shall be kept for a period of five years from the date the change was made or until permit reissuance, whichever is longer. For nonexpiring permits, these records shall be kept for a period of five years from the date that the change was made. The records shall be kept at the stationary source for the current calendar year of operation and may be kept at the stationary source or office of the stationary source for all other years. The records may be maintained in either electronic or paper format. REPORTING/SUBMITTALS Minn. R , subp. 5(C) Minn. R , subp. 5(B) Minn. R , subp. 4 hdr

7 TABLE A: LIMITS AND OTHER REQUIREMENTS A-4 11/25/08 Facility Name: Minnesota Power - Laskin Energy Center Permit Number: Shutdown Notifications: Notify the Commissioner at least 24 hours in advance of a planned shutdown of any control equipment or process equipment if the shutdown would cause any increase in the emissions of any regulated air pollutant. If the owner or operator does not have advance knowledge of the shutdown, notification shall be made to the Commissioner as soon as possible after the shutdown. However, notification is not required in the circumstances outlined in Items A, B and C of Minn. R , subp. 3. At the time of notification, the owner or operator shall inform the Commissioner of the cause of the shutdown and the estimated duration. The owner or operator shall notify the Commissioner when the shutdown is over. Breakdown Notifications: Notify the Commissioner within 24 hours of a breakdown of more than one hour duration of any control equipment or process equipment if the breakdown causes any increase in the emissions of any regulated air pollutant. The 24-hour time period starts when the breakdown was discovered or reasonably should have been discovered by the owner or operator. However, notification is not required in the circumstances outlined in Items A, B and C of Minn. R , subp. 2. At the time of notification or as soon as possible thereafter, the owner or operator shall inform the Commissioner of the cause of the breakdown and the estimated duration. The owner or operator shall notify the Commissioner when the breakdown is over. Shutdown and Breakdown Reporting Requirement for the Dust Collector Systems for Material Handling Equipment: Minn. R , subp. 3 Minn. R , subp. 2 Minn. R , subp. 2 Shutdowns and breakdowns shall be reported on a quarterly basis to the Agency. The quarterly report shall include an identification of any dust collector that experienced a breakdown and/or shutdown, the time and reason for the breakdown or shutdown, a description of any repairs made, and the date and time the dust collector was placed back in service. Notification of Deviations Endangering Human Health or the Environment: As soon Minn. R , subp. 1 as possible after discovery, notify the Commissioner or the state duty officer, either orally or by facsimile, of any deviation from permit conditions which could endanger human health or the environment. Notification of Deviations Endangering Human Health or the Environment Report: Minn. R , subp. 1 Within 2 working days of discovery, notify the Commissioner in writing of any deviation from permit conditions which could endanger human health or the environment. Include the following information in this written description: 1. the cause of the deviation; 2. the exact dates of the period of the deviation, if the deviation has been corrected; 3. whether or not the deviation has been corrected; 4. the anticipated time by which the deviation is expected to be corrected, if not yet corrected; and 5. steps taken or planned to reduce, eliminate, and prevent reoccurrence of the deviation. Application for Permit Amendment: If a permit amendment is needed, submit an Minn. R through Minn. R application in accordance with the requirements of Minn. R through Minn. R Submittal dates vary, depending on the type of amendment needed. Extension Requests: The Permittee may apply for an Administrative Amendment to Minn. R , subp. 1(H) extend a deadline in a permit by no more than 120 days, provided the proposed deadline extension meets the requirements of Minn. R , subp. 1(H). Emission Inventory Report: due on or before April 1 of each calendar year following Minn. R through Minn. R permit issuance. The Permittee shall submit this on a form approved by the Commissioner. Emission Fees: due 60 days after receipt of an MPCA bill. Minn. R through Minn. R

8 TABLE A: LIMITS AND OTHER REQUIREMENTS A-5 11/25/08 Facility Name: Minnesota Power - Laskin Energy Center Permit Number: Subject Item: Associated Items: GP 001 Boilers CE 004 Low Nox Burners CE 005 Low Nox Burners CE 006 Overfire Air CE 007 Overfire Air EU 001 Boiler - Unit #1; CE 001, CE 004, CE 006 EU 002 Boiler - Unit #2; CE 002, CE 005, CE 007 SV 001 Common Boiler Stack What to do The Permittee shall meet either option 1 or option 2: 1.a. Individually validate EU 001 and EU 002 CO emissions are less than or equal to the EU 001 and EU 002 CO lb/mmbtu emission factor, and 1.b. Monitor, record, and report GP 001 emissions as required by 40 CFR Section 52.21(r)(6); Why to do it Title I Condition: 40 CFR Sections 52.21(b) & 52.21(r)(6) and Minn. R OR 2. Meet the GP ton per year (12-month rolling sum basis) CO limit and all associated monitoring, recordkeeping, and reporting requirements in table A of this permit. If either EU 001 or EU 002 CO emission factor testing results in a factor greater than lb/mmbtu, the Permittee shall follow option 2 and associated CO monitoring and recordkeeping requirements in EU 001, EU 002, and GP 001 in table A of this permit. Reverting From Option 2 To Option 1: The Permittee may revert from option 2 to option 1 under the following conditions: Title I Condition: 40 CFR Sections 52.21(b) & 52.21(r)(6) and Minn. R a subsequent CO performance test on the same emission unit that previously tested above lb/mmbtu measures CO emissions no greater than lb/mmbtu; 2. the Permittee continues to follow Section 52.21(r)(6) requirements during the five-year period following the resumption of regular operation after completion of modifications of both units, regardless if option 2 applies. If both units previously tested above lb/mmbtu, subsequent CO performance tests must show CO emissions no greater than lb/mmbtu for both units in order to revert to option 1. This permit provision expires 5 years following resumption of regular operations after completion of modifications of both units. Carbon Monoxide: less than or equal to 630 tons/year using 12-month Rolling Sum for both boilers combined. This limit applies at the end of the twelfth month after initial startup of the first modified boiler, if the Permittee elects or is required to meet this limit. Carbon Monoxide: If the Permittee elects to or is required to meet the GP ton per year CO limit, the following cumulative limit as of month 'n' where n = 1, 2, 3, etc. applies after initial startup of the first modified boiler: Title I Condition: To avoid major modification under 40 CFR Section 52.21(b) and Minn. R Title I Condition: To avoid major modification under 40 CFR Section 52.21(b) and Minn. R Month 1: 100 tons Month 2: 200 tons Month 3: 275 tons Month 4: 350 tons Month 5: 400 tons Month 6: 450 tons Month 7: 490 tons Month 8: 520 tons Month 9: 550 tons Month 10: 580 tons Month 11: 610 tons Month 1 includes the month of initial startup of the first modified boiler. This requirement terminates at the end of the twelfth month following initial startup of the first modified boiler.

9 TABLE A: LIMITS AND OTHER REQUIREMENTS A-6 11/25/08 Facility Name: Minnesota Power - Laskin Energy Center Permit Number: Carbon Monoxide: less than or equal to tons/year on a calendar year basis for both boilers combined. This limit and associated recordkeeping is suspended if CO emission factor testing of EU 001 and EU 002 demonstrates a CO emission factor less than or equal to lb/mmbtu for each emission unit. This limit is re-instated if a subsequent EU 001 or EU 002 CO emission factor test measures CO in excess of lb/mmbtu. GP 001 CO Emissions Monitoring and Recordkeeping: If the Permittee elects to or is required to meet the ton per year GP 001 CO limit, by the last day of each month the Permittee shall calculate and record: Minn. R , subp. 2 to avoid 100 tpy environmental review potential emission increase threshold Title I Condition: To avoid major modification under 40 CFR Section 52.21(b) and Minn. R monthly GP 001 CO emissions for the previous calendar month by summing the EU 001 CO and EU 002 CO emissions determined according to the requirements listed under EU 001 and EU 002, respectively, from the previous calendar month; 2. GP 001 CO emissions from the previous twelve-month period by summing the monthly GP 001 CO emissions from the previous twelve months. GP 001 CO Emissions Monitoring and Recordkeeping: The Permittee shall calculate and record the GP 001 calendar year CO emissions by January 30 of each year, for the previous calendar year. If either EU 001 or EU 002 CO emission factor testing results in a factor greater than lb/mmbtu, the Permittee may opt to perform additional analyses to demonstrate that the CO emissions performance satisfies Prevention of Significant Deterioration requirements under 40 CFR Section 52.21, and obtain a permit according to 40 CFR Section Combustion Of Oily Cellulose-Based Sorbents (including rags): The Permittee is permitted to burn oily cellulose-based sorbent and rags in both boilers. The materials must be cellulose-based and are subject to the following limits: 1) 1.25 tons per hour; and 2) 25 tons per year (on a 12-month rolling sum basis). Minn. R , subp. 4 and 5 to avoid 100 tpy environmental review potential emission increase threshold 40 CFR Section 52.21(a)(2)(iii) Title I Condition: to ensure that the emissions increase from the addition of the fuel type is less than significant as defined by 40 CFR Section and Minn. R The Permittee shall record the quantity of sorbent materials burned on an hourly and 12-month rolling sum basis.

10 TABLE A: LIMITS AND OTHER REQUIREMENTS A-7 11/25/08 Facility Name: Minnesota Power - Laskin Energy Center Permit Number: Subject Item: GP 002 Scrubbers What to do THE FOLLOWING REQUIREMENTS APPLY TO EACH SCRUBBER INDIVIDUALLY The Permittee shall operate and maintain the scrubbers (CE 001 and CE 002) at all times that any emission unit controlled by the scrubbers (EU 001 and EU 002) is in operation. The Permittee shall document periods of non-operation of the control equipment. The Permittee shall operate and maintain control equipment such that it achieves an overall control efficiency for Total Particulate Matter: greater than or equal to 90 percent The Permittee shall operate and maintain the scrubbers in accordance with the Operation and Maintenance (O & M) Plan. The Permittee shall keep copies of the O & M Plan available onsite for use by staff and MPCA staff. Temperature: less than or equal to 175 degrees F using 3-hour Average at the common stack, unless a new limit is set pursuant to Minn. R , subp. 3 based on the values recorded during the most recent MPCA-approved performance test where compliance was demonstrated. The new limit shall be implemented upon receipt of the Notice of Compliance letter granting preliminary approval. The limit is final upon issuance of a permit amendment incorporating the change. If the 3-hour rolling average temperature is above the maximum temperature limit, the PM emitted during that time shall be considered uncontrolled until the average temperature is below the maximum temperature limit. This shall be reported as a deviation. Temperature Monitoring: The Permittee shall maintain and operate a thermocouple monitoring device that continuously indicates and records the stack temperature. The monitoring equipment must be in use and properly maintained whenever operation of the monitored control equipment is required. The monitoring device shall have a margin of error less than +/- 2.0 percent of the temperature being measured. The recording device shall also calculate the three-hour rolling average temperature. Recorded values outside the range specified in this permit are considered Deviations as defined by Minn. R , subp. 8a. Opacity: less than or equal to 20 percent using 3-hour average, unless a new limit is set pursuant to Minn. R , subp. 3 based on the values recorded during the most recent MPCA-approved performance test where compliance was demonstrated. The new limit shall be implemented upon receipt of the Notice of Compliance letter granting preliminary approval. The limit is final upon issuance of a permit amendment incorporating the change. If the 3-hour rolling average opacity is above the maximum opacity limit, the PM emitted during that time shall be considered uncontrolled until the average opacity is below the maximum opacity limit. This shall be reported as a deviation. Opacity Monitoring: The Permittee shall maintain and operate an opacity monitoring device that continuously indicates and records the opacity of the stack. The monitoring equipment must be in use and properly maintained whenever operation of the monitored control equipment is required. The monitoring device shall have a margin of error less than +/- 2.0 percent. The recording device shall also calculate the three-hour rolling average. Recorded values outside the range specified in this permit are considered Deviations as defined by Minn. R , subp. 8a. Daily Monitoring: The Permittee shall physically verify the operation of the temperature recording device at least once each operating day to verify that it is working and recording properly. The Permittee shall maintain a written or electronic record of the daily verifications. The Permittee shall maintain a high temperature alarm for the boiler operator. The Permittee shall maintain a continuous hard copy readout or computer disk file of the temperature and opacity readings and calculated three hour rolling average temperatures and opacity at the common stack. Annual Calibration: The Permittee shall calibrate the temperature monitor at least annually and shall maintain a written record of the calibration and any action resulting from the calibration. Quarterly Inspections: At least once per calendar quarter, the Permittee shall inspect the control equipment internal and external system components. The Permittee shall maintain a written record of the inspection and any corrective actions taken resulting from the inspection. Annual Inspection: At least once per calendar year, the Permittee shall conduct an internal inspection of the control device that includes all operating systems of the control device. The Permittee shall maintain a written record of the inspection and any action resulting from the inspection. hdr Why to do it Minn. R , subps. 2 and 14 Minn. R , subps. 2 and CFR Section 64.7(b); Minn. R Minn. R , subps. 2 and 14 Minn. R , subps. 2 and 14; 40 CFR Section 64.3(b)(4)(ii); Minn. R ; 40 CFR Section 64.7(b); Minn. R Minn. R , subps. 2 and 14; 40 CFR Section 64.3(b)(4)(ii); Minn. R Minn. R , subps. 2 and 14; 40 CFR Section 64.3(b)(4)(ii); Minn. R ; 40 CFR Section 64.7(b); Minn. R Minn. R , subps. 2 and 14; 40 CFR Section 64.3(b); Minn. R Minn. R , subps. 2 and 14; 40 CFR Section 64.9(b); Minn. R CFR Section 64.3; Minn. R CFR Section 64.3; Minn. R CFR Section 64.3; Minn. R

11 TABLE A: LIMITS AND OTHER REQUIREMENTS A-8 11/25/08 Facility Name: Permit Number: Minnesota Power - Laskin Energy Center For periods when the scrubber exhaust is below the maximum temperature and opacity, the Permittee shall use either one of the following when completing calculations as required elsewhere in this permit: a. The overall control efficiency limit specified in this permit for this equipment (90%); or b. The overall control efficiency determined during the most recent MPCA approved performance test. If the tested efficiency is less than the efficiency limit in this permit, the Permittee must use the tested value in all calculations until the efficiency is demonstrated to be above the permit limit through a new test. Corrective Actions: If the temperature and/or opacity is above the maximum specified by this permit or if the scrubber or any of its components are found during the inspections to need repair, the Permittee shall take corrective action as soon as possible. Corrective actions shall return the temperature and/or opacity to at least the permitted maximum and/or include completion of necessary repairs identified during the inspection, as applicable. Corrective actions include, but are not limited to, those outlined in the O & M Plan for the scrubbers. The Permittee shall keep a record of the type and date of any corrective action taken. Documentation of Need for Improved Monitoring: If the Permittee fails to achieve compliance with an emission limitation or standard for which the monitoring did not provide an indication of an excursion or exceedance while providing valid data, or the results of compliance or performance testing document a need to modify the existing maximum exhaust temperature, the Permittee shall promptly notify the MPCA and, if necessary, submit a permit amendment application to address the necessary monitoring changes. As required by 40 CFR Section 64.9(a)(2), for the Semi-Annual Deviations Report listed in Table B of this permit and/or the Notification of Deviations Endangering Human Health and the Environment listed earlier in Table A of this permit, as applicable, the Permittee shall include the following related to the monitoring identified as required by 40 CFR pt. 64: 1) Summary information on the number, duration, and cause of excursions or exceedances, as applicable, and the corrective action taken; and 2) Summary information on the number, duration, and cause for monitor downtime incidents. The Permittee shall maintain records of monitoring data, monitor performance data, corrective actions taken, and other supporting information required to be maintained. The Permittee may maintain records on alternative media, such as microfilm, computer files, magnetic tape disks, or microfiche, provided that the use of such alternative media allows for expeditious inspection and review, and does not conflict with other applicable recordkeeping requirements. Minn. R , subp. 4 and 5 40 CFR Section 64.7(d); Minn. R CFR Section 64.7(e); Minn. R CFR Section 64.9(a)(2); Minn. R CFR Section 64.9(b); Minn. R

12 TABLE A: LIMITS AND OTHER REQUIREMENTS A-9 11/25/08 Facility Name: Minnesota Power - Laskin Energy Center Permit Number: Subject Item: SV 001 Common Boiler Stack Associated Items: EU 001 Boiler - Unit #1; CE 001, CE 004, CE 006 EU 002 Boiler - Unit #2; CE 002, CE 005, CE 007 GP 001 Boilers MR 002 MR 005 MR 006 Flow X-pattern MR 007 Opacity MR 008 SO2 MR 009 NOx MR 010 CO2 What to do ADDITIONAL MR REQUIREMENTS LOCATED AT THE INDIVIDUAL MR LEVEL hdr Why to do it Sulfur Dioxide: less than or equal to 2.04 lbs/million Btu heat input using 1-Hour Average. Refer to EU 001 and EU 002 for the SO2 limit applicable to each emission unit. Nitrogen Oxides: less than or equal to 0.20 lbs/million Btu heat input using 365-day Rolling Average COMS Monitoring Data: Owners or operators of all COMS shall reduce all data to a one-minute averaging period. Opacity averages shall be calculated from all equally spaced consecutive 10-second (or shorter) data points in the one-minute averaging period. COMS Calibration Error Audit: due before end of each calendar half-year following COMS Certification Test. Conduct three point calibration error audits at least 3 months apart but no greater than 8 months apart. Conduct audits in accordance with Minn. R , subp. 3. COMS Continuous Operation: COMS must be operated and data recorded during all periods of emission unit operation including periods of emission unit start-up, shutdown, or malfunction except for periods of acceptable monitor downtime. This requirement applies whether or not a numerical emission limit applies during these periods. A COMS must not be bypassed except in emergencies where failure to bypass would endanger human health, safety, or plant equipment. Minn. Stat. Section , subds. 4a & 9; Minn. R , subps 7A, 7L & 7M; Minn. R , subps. 1, 2 & 4; Minn. R Minn. R , subp. 2; this is a state-only requirement not enforceable by the EPA administrator or citizens under the Clean Air Act Minn. R , subps. 1, 2 and 3 Minn. R , subp. 3 Minn. R , subp. 1 Acceptable monitor downtime includes reasonable periods as listed in Items A, B, C and D of Minn. R , subp. 2. COMS Daily Calibration Drift Check: The Permittee must automatically, intrinsic to the opacity monitor, check the zero and upscale (span) calibration drifts at least once daily. The acceptable range is as defined in 40 CFR pt. 60, Appendix B, PS-1. The COMS must be adjusted whenever the calibration drift (CD) exceeds twice the specification of 40 CFR 60, Appendix B, PS-1. Recordkeeping: The owner or operator must retain records of all COMS/CEMS monitoring data and support information for a period of five years from the date of the monitoring sample, measurement, or report. Records shall be kept at the source. CEMS QA/QC The owner or operator of an affected facility shall operate, calibrate, and maintain each CEMS according to the QA/QC procedures in 40 CFR pt. 75, Appendix B as amended. Daily Calibration Error (CE) Test: conduct daily CE testing on all CEMS required by the Acid Rain Program, in accordance with 40 CFR pt. 75 App B. CEMS Relative Accuracy Test Audit (RATA): due before the end of each calendar half year following CEM Certification Test (or due each year, depending on the results of the previous test). Conduct a RATA on all CEMS required by the Acid Rain Program, in accordance with 40 CFR pt. 75 App B. If the RATA results indicate a relative accuracy of 7.5% or less, the next RATA is not required for another year. Minn. R , subp. 2 Minn. R CFR Section CFR pt. 75 App B, section CFR pt. 75 App B, section 2.3

13 TABLE A: LIMITS AND OTHER REQUIREMENTS A-10 11/25/08 Facility Name: Minnesota Power - Laskin Energy Center Permit Number: Linearity and Leak Check Test (Acid Rain Program): due before end of each calendar quarter following CEM Certification Test. Conduct a quarterly linearity test on all CEMS required by the Acid Rain Program, in accordance with 40 CFR pt. 75 App B. Relative Accuracy Test Audit (RATA) Notification: due 30 days before CEMS Relative Accuracy Test Audit (RATA). 40 CFR pt. 75 App B, section 2.2 Minn. R , subp. 2

14 TABLE A: LIMITS AND OTHER REQUIREMENTS A-11 11/25/08 Facility Name: Permit Number: Minnesota Power - Laskin Energy Center Subject Item: EU 001 Boiler - Unit #1; CE 001, CE 004, CE 006 Associated Items: CE 004 Low Nox Burners CE 006 Overfire Air GP 001 Boilers SV 001 Common Boiler Stack What to do LIMITS AND OPERATING REQUIREMENTS hdr Why to do it Total Particulate Matter: less than or equal to 0.60 lbs/million Btu heat input Minn. R , subp. 1 Opacity: less than or equal to 20 percent opacity using 6-minute Average except for one six-minute period per hour of not more than 60 percent opacity. Sulfur Dioxide: less than or equal to 4.0 lbs/million Btu heat input using 1-Hour Average period for solid fuels, and 2.0 lb/mmbtu when burning liquid fuels. When fossil fuels are burned simultaneously in any combination, the applicable standard shall be determined by proration using the following formula: w=[2y+4z]/(y+z) where y is the % heat input from liquid fossil fuel and z is the % heat input from solid fossil fuels. Refer to SV 001 for additional SO2 limit applicable to the common stack. Nitrogen Oxides: less than or equal to 0.20 lbs/million Btu heat input using 365-day Rolling Average Carbon Monoxide: less than or equal to lbs/million Btu heat input (this is an emission factor and not a limit). The Permittee shall validate this factor through performance testing. If performance testing shows a factor greater than lb/mmbtu, the Permittee shall meet the GP tpy limit. Fuel use: limited to sub-bituminous and bituminous coal, distillate oil, natural gas, boiler cleaning agents, non-hazardous petroleum distillate solvents and derived fuels, used oil, oily coal (coal with oil spilled on it), and oily cellulose-based sorbents (including rags). Boiler cleaning agents limited to: EDTA type and Ammonium Bromate, are generated on-site, 5% of total fuel mass, oxygen limited to 3% or greater, agents may only be burned while the boiler is operating at 75 percent of rated capacity or greater. Fuel Usage: less than or equal to 720 gallons/hour and less than 2,500,000 gallons annually of off-specification and on-specification used oil. Used oil shall be burned in accordance with Minn. R. ch EU 001 Bituminous Coal Operations: If the Permittee combusts any bituminous coal, the Permittee shall conduct a CO performance test while burning bituminous coal. The Permittee may continue burning bituminous coal in EU 001 after completion of testing. EU 001 CO Emissions Indicator: The Permittee shall operate EU 001 so that CO (ppm) measured by the emissions indicator does not exceed a value based on values measured during the most recent MPCA-approved performance stack test for evaluating the EU 001 CO emission factor. The current CO emission indicator is 100 ppm on a 30-day rolling average based on July 2007 test data. ACID RAIN PROGRAM REQUIREMENTS Comply with the applicable Acid Rain emissions limitation for sulfur dioxide. Takes effect for years beginning January 1, Application for NOx limits: Submit a complete permit application and compliance plan for NOx emissions in accordance with 40 CFR Section Minn. R , subp. 2 Minn. R , subp. 1 Minn. R , subp. 2; this is a state-only requirement not enforceable by the EPA administrator or citizens under the Clean Air Act Title I Condition: To avoid major modification under 40 CFR Section 52.21(b) and Minn. R Minn. Stat. Section , subd. 4a; Minn. R , subp. 2 Minn. Stat. Section , subd. 4a; Minn. R , subp. 2 Minn. Stat. Section , subd. 4a; Minn. R , subp. 2 Title I Condition: To avoid major modification under 40 CFR Section 52.21(b) and Minn. R Title I Condition: To avoid major modification under 40 CFR Section 52.21(b) and Minn. R hdr 40 CFR Section 72.9(c)(1)(ii), 40 CFR Section 72.9(g)(4) 40 CFR Section 76.9(b)(2)

15 TABLE A: LIMITS AND OTHER REQUIREMENTS A-12 11/25/08 Facility Name: Minnesota Power - Laskin Energy Center Permit Number: NOx Averaging Plan 40 CFR Section Beginning January 1, 2000 either: Maintain an annual average NOx emission rate of 0.40 lbs/mmbtu and limit the annual heat input to less than or equal to 4,600,000 mmbtu per year. OR Maintain a Btu-weighted annual average emission rate in lbs/mmbtu, averaged over the units specified in the NOx averaging plan, that is less than or equal to the Btu-weighted annual average emission rate averaged over the same units had they each been operated during the same period of time in compliance with the applicable emission limitations in 40 CFR Sections 76.5, 76.6, or Units covered in the plan are: Plant Boiler ID# Clay Boswell 1, 2, 3, 4 Syl Laskin 1, 2 Taconite Harbor 1, 2, 3 Recordkeeping: Keep on site at the source each of the following documents for a period of 5 years from the date the document is created: The certificate of representation, all emissions monitoring information, copies of all reports, compliance certifications, and other submissions or records made under the Acid Rain Program, copies of all documents used to complete an acid rain permit application. Apply for Acid Rain Program Permit reissuance: The designated representative shall submit a complete Acid Rain permit application for each source with an affected unit at least 6 months prior to the expiration of an existing Acid Rain Permit in accordance with 40 CFR Section 72.30(c). Certify Acid Rain Program Submittals. Each submission under the Acid Rain Program shall be submitted, signed, and certified by the designated representative or the alternate designated representative for all sources on behalf of which the submission is made in accordance with 40 CFR Section Hold allowances as of the allowance transfer deadline, in the unit's compliance subaccount not less than the total annual emissions of sulfur dioxide for the previous calendar year. Takes effect for years beginning January 1, Allowances shall be held in, deducted from, or transferred among Allowance Tracking System accounts in accordance with the Acid Rain Program. The owner or operator shall measure opacity, and all SO2, NOx, and CO2 emissions for each affected unit in accordance with 40 CFR Section PERFORMANCE TESTING 40 CFR Section 72.9(f)(l) 40 CFR Section 72.30(c) 40 CFR Section CFR Section 72.9(c)(1)(i), 40 CFR Section 72.9(g)(4) 40 CFR Section hdr Performance Test: due before end of each calendar 60 months starting 07/25/2007 to evaluate compliance with the CO emission factor to avoid major modification under 40 CFR Section 52.21(b) and Minn. R The tests shall be conducted at an interval not to exceed 60 months between test dates. The test shall be conducted while combusting coal as a single fuel, a combination of coal and fuel oil, and a combination of coal and natural gas. A one-time 60-day extension was granted in Performance Test: due before end of each 60 months starting 06/03/1997 to determine compliance with the particulate matter emissions limit in Minn. R subp 1. The tests shall be conducted at an interval not to exceed 60 months between test dates. A one-time 120-day extension was granted in Boiler Alternative Operating Conditions for Performance Testing: Minn. R , subp.1 Minn. R , subp. 1 Minn. R , subp. 2.A. and 3.B. Alternative Operating Conditions during testing are defined as 90% to 100% of the boiler's maximum normal (continuous) operating load or the maximum permitted operating rate, whichever is lower. The basis for this number must be included in the test plan. If testing is conducted at the alternative operating condition established, an operating limit will not be established as a result of performance testing. In no case will the new operating rate limit be higher than allowed by an existing permit condition.

16 TABLE A: LIMITS AND OTHER REQUIREMENTS A-13 11/25/08 Facility Name: Minnesota Power - Laskin Energy Center Permit Number: Boiler Operating Conditions Not Meeting the Alternative Operating Conditions During Performance Testing: Minn. R , subp. 3.B. If performance testing is not conducted at or above the established alternative operating condition, then the boiler operating rate will be limited on an 8-hour block average based on the following: (1) If the results of the performance test are greater than 80% of any applicable emission limit for which compliance is demonstrated, then boiler operation will be limited to the tested operating rate. (2) If results are less than or equal to 80% of all applicable emission limits for which compliance is demonstrated, boiler operation will be limited to the tested operating rate. In no case will the new operating rate limit be higher than allowed by an existing permit condition. STET (Short Term Emergency and Testing) Operating hours limit: The boiler may operate up to 40 hours per year to demonstrate the Uniform Rating of Generating Equipment (URGE) capacity and to meet emergency energy supply needs. Maintain documentation of all STET operation to demonstrate compliance with this limit. The boiler must meet emission limits during STET operation. STET Operation Definition that applies to Boilers that Meet or do Not Meet the Alternative Operating Condition for Performance Testing: Minn. R , subp. 2 Minn. R , subp. 2 If performance test results demonstrate compliance at 80% or less of any applicable emission limits for any tested pollutant, STET operation is defined as operation beyond 110% of the average operating rate achieved during that performance test. If performance test results demonstrate compliance at greater than 80% of any applicable emission limit for any tested pollutant, STET operation is defined as operation beyond 100% of the average operating rate achieved during that performance test. In no case will STET operation be higher than allowed by an existing permit condition. The results of a performance test are not final until issuance of a review letter by MPCA, unless specified otherwise by Minn. R MONITORING AND RECORDKEEPING Minn. R , subp. 4 hdr Recordkeeping: maintain records of the occurrence and duration of any startup, shutdown, or malfunction in the operation of the facility including malfunction of the air pollution control equipment or any periods during which a continuous monitoring system or monitoring device is inoperative. Excess emissions and monitoring system performance reports shall include the information required in 40 CFR Section 60.7(c) and (d). MPCA supplied forms DRF-1 and DRF-2 may be used to meet this requirement. EU 001 CO Emissions Indicator Monitoring and Recordkeeping: Calculate the arithmetic average of all hourly emission rates for CO for 30 calendar days. The 30-day rolling hourly average is calculated once each calendar day by summing the hourly CO emission concentrations measured during the previous 30 calendar days, and dividing by the number of hourly data values. Downtime of greater than one hour duration shall not be included in the 30-day rolling average. EU 001 CO Emissions Indicator Monitoring and Recordkeeping: The Permittee shall install, operate, and maintain a process CO monitor (ppm monitor primarily for the boiler operator) upstream of the EU 001 air heater, and record the indicator measurements. The monitoring and recordkeeping equipment shall be operated and maintained at all times during EU 001 operation. CO concentration will not exceed a value based on values recorded during the most recent MPCA-approved performance test. The measurement frequency and averaging period associated with this emissions indicator will be derived by the Permittee through analysis of the correlation between indicator readings and the first performance test results. Minn. R , supb. 2 Minn. R , subp. 2 Title I Condition: To avoid major modification under 40 CFR Section 52.21(b) and Minn. R Title I Condition: To avoid major modification under 40 CFR Section 52.21(b) and Minn. R