COMPLIANCE ASSURANCE MONITORING

MINNKOTA POWER COOPERATIVE, INC.

Milton R Young Station

February 1, 2010

Page 1 of 23MINNKOTA POWER COOPERATIVE, INC. Milton R. Young Station Compliance Assurance Monitoring Plan Electrostatic Precipitator I. Background A. Emission Units: Lignite-fired boilers Description: Electrostatic Precipitator (ESP) EP 1 Location: Unit 1 EP 2 Location: Unit 2 B. Applicable Regulation, Emission Limit and Monitoring Requirements Unit 1 Regulation: Title V Permit Number T5-F76009, NDAC 33-15-05-01.2 Emission Limit: Opacity 20% Particulate: EP 1- 0.10 lb/10 6 BTU PMIO: EP 1 - 160.3 lb/hr Unit 2 Regulation: Title V Permit Number T5-F76009, NDAC 33-15-12, Subpart D and 33-15-03-02 Emission Limit: Opacity 20% Particulate: EP 2- 0.03 lb/10 6 BTU
Page 2 of 23PMIO: EP 2 - 315.1 lb/hr II. Monitoring Approach The key elements of the monitoring approach are presented in Table 1. Table No. 1 Monitoring Approach ESP for PM Control Emission Points: 1 & 2 Indicator No. 1 I. Indicator Stack Opacity The opacity is measured using a Continuous Opacity Monitor (COMS) Measurement Approach at the stack of both units An excursion is defined as a measured stack opacity greater than 20 percent, based on a 3-hour block average. excluding startup/shutdown and malfunctions. Excursions trigger a reporting requirement. Corrective action must be initiated when measured stack opacity is greater than 20 percent based on a 1-hour block II. Indicator Range average. III. Performance Criteria Opacity is related to particulate emissions. As opacity increase it can Data be assumed the particulate emissions Representativeness increase. Daily zero and span calibrations, cleaning of the optical surface of the QA/QC COMS, QA/QC checks per applicable Performance Specification 1. Monitoring Frequency Continuous The COMS records a 1 minute opacity average which is averaged for 1 minute, Averaging Period 6 minute and 1 hour averages. Evaluate the cause of the increased Page 3 of 23opacity. The evaluation will include the ESP rappers, ESP electrical components, ash removal and ash transport systems. Corrective actions will be completed as soon as practically possible. A reduction of the generator electrical output to reduce ash loading to Corrective Action the ESP if necessary.
MONITORING APPROACH JUSTIFICATION
I. Background The Milton R. Young Station consists of two cyclone-fired boilers. Each of the boilers exhaust through dedicated stacks. Unit 1 has a rated heat input of 3200 X 106 BTU/hr and Unit 2 has a rated heat input of 6200 X 10 6 BTU/hr. Both boilers fire lignite and Number 2 fuel oil during startup and to clear the cyclone burners of slag. Particulate emissions are controlled by, two side by side cold side ESP's per unit. Each of the Unit ESP's consists of eight transformer rectifier (TR) sets. The Unit 2 ESP's consist of sixteen TR sets. II. Justification for Selected Performance Indicators A test and cap approach was taken to determine the particulate emissions at or near 20 percent opacity. If the particulate emission limits, are determined not to be exceeded at 20 percent opacity two triggers are set. The first trigger point indicates a possible problem with the COMS, ESP or the ash transport system and action should be taken. The second trigger is an excursion and is a reportable event under Compliance Assurance Monitoring CAM. Unit 1 Test Results Table 2, Figure 1 and Figure 2 show the results of the particulate testing completed on Unit 1. Total Stack Particulate PMIo Opacity Emissions Emissions Condition ( 0 /0) (lb/10 6 BTU) 1 ( b/hr) Baseline 3.1 0.0074 15.23 Baseline 3.4 0.0071 16.24 Baseline 5.0 0.0108 21.61 De-tuned (mid) 11.5 0.0301 66.83 De-tuned (mid) 11.6 0.0271 65.59 Page 4 of 23De-tuned (mid) 14.6 0.0442 112.96 De-tuned (high) 14.8 0.0420 101.49 De-tuned (high) 15.1 0.0397 80.22 De-tuned (high) 20.8 0.0665 163.68 Table 2. Unit 1 CAM Testing Results The Unit 1 emission limits for total particulate and PMio are 0.10 (lb/10 6 BTU) and 160.3 (lb/hr) respectively. The data for the baseline condition shows an average opacity of 3. 8 percent and emissions of 0.0084 (lb/10 6 BTU) for total particulate and 17.7 (lb/hr) for PM10, which are well below the respective emission limits. To achieve an increased opacity the ESP was de-tuned by shutting down or reducing power to TR sets. The mid range opacity on Unit 1 was achieved by shutting down 8 of 16 TR sets. The high range opacity was achieved by, shutting down 8 of 16 TR sets and reducing to 50 percent power 2 of the remaining 8 TR sets.

ABl AB1 CD1 CD1
AB2 AB2 02 CD2 

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A84 AB4 CD4 CD4
AB5 AB5 CD5 CD5
AB6 AB6 CD6 CD6
AB7 AB7 CD7 CD7
AB8 AB8 CD8 CD
TR off
Page 5 of 23Unit 1 ESP De-tuned Mid Opacity



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### AB2 AB2 CD2 CD2


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AB4 AB4 CD4 CD4
AB5 .PiBS CDS CD5
AB6 AB6 CD6 CD6
AB7 AB7 CD7 CD7
AB8 AB8 CD8 CD
TR off TR %z, power

Page 6 of 23Unit 1 ESP De-tuned High Opacity

JIF, 0.10 3 m 0.08

~ ~ 0.06 .Q g 0.04 a 0.02 o l i l Unit 1 PM♦ Total Particulate Emission Limit

0.0 5.0 10.0 15.0 20.0 25.0

Opacity (%)

Figure 1 Figure 1 is a graph of opacity and total particulate for the Unit 1 performance testing for the baseline as well as the de-tuned ESP operating scenario at a normal generator output. The linear regression shows a worst-case scenario for particulate emissions at 20 percent opacity to be 0.062 (lb/10 6 BTU). The particulate emissions under the worst-case scenario are about 62 percent of the permitted emission limit.
Unit 1 PM 10 180.0 160.0 140.0 s 120.0 ~ 100.0 ° 80.0 a 60.0 40.0 20.0 0.0 _ --- ~

~ ~®

~ ~ 0.0 5.0 10.0 15.0 20.0 25.0

Opacity (%)♦ PM10 Emission Limit

The data shows a margin for compliance with CAM.
Page 7 of 23Figure 2

Figure 2 is a graph of opacity and PM10 for the Unit 1 performance testing for the baseline as well as the de-tuned ESP operating scenario at a normal generator output. The linear regression shows a worst-case scenario for particulate emissions at 20 percent opacity to be 150 (lb/hr). The particulate emissions under the worst-case scenario are about 94 percent of the permitted emission limit. The data shows a margin for compliance with CAM. Unit 2 Test Results Table 3, Figure 3 and Figure 4 show the results of the particulate testing completed on Unit 2. Total Stack Particulate PMIo Opacity Emissions Emissions Condition 

### °/a (lb/lO 6 BTU) 1 ( b/hr) Baseline 10.8 0.0059 23.96 Baseline 11.0 0.0067 25.79 Baseline 11.0 0.0063 25.14 De-tuned (mid) 13.7 0.0127 47.05 De-tuned (mid) 15.3 0.0121 54.37 De-tuned (mid) 17.0 0.0165 80.88 De-tuned (high) 19.3 0.0194 77.90 De-tuned (high) 19.9 0.0228 89.78 De-tuned (high) 20.0 0.0234 93.06 Table 3. Unit 2 CAM Testing Results
The Unit 2 emission limits for total particulate and PMIO are 0.03 (lb/10 6 BTU) and 315.1 (lb/hr) respectively. The data for the baseline condition shows an average opacity of 10.9 percent and emissions of 0.0063 (lb/10 6 BTU) for total particulate and 25.0 (lb/hr) for PMIo, which are well below the respective emission limits. To achieve an increased opacity the ESP was de-tuned by shutting down or reducing power to TR sets. The mid range opacity on Unit 2 was achieved by shutting down 16 of 32 TR sets. The high range opacity was achieved by, shutting down 16 of 32 TR sets and reducing to 50 percent power to 4 of the remaining 16 TR sets.

Page 8 of 23lA1 2A1 3A1 4A1 1B1 2B1. 3B1 4B1

lA2 2A2 3A2 4A2 1B2 2B2 3B2 4B2
lA3 2A3 3A3 4A3 1B3 2B3 3B3 4B3
lA4 2A4 3A4 4A4 1B4 2B4 3B4 4B4

TR o.ff Unit 2 ESP De-tuned Mid Opacity

lAl 2A1. 3A1 4A1 lBl 2B1 

### 381 4B1
lA2 2A2 3A2 4A2 182 2B2 3B2 

### 492
1A3 2A3 3A3 4A3 1B3 2133 3B3 4B3
lA4 2A4 3A4 4A4 1B4 2B4 3B4 4B4
TR .Off 

## TR Power

Page 9 of 23Unit 2 ESP De-tuned High Opacity Figure 3 Figure 3 is a graph of opacity and total particulate for the performance testing for Unit 2 for the baseline as well as the de-tuned ESP operating scenario at a normal generator output. The linear regression shows a worst-case scenario for particulate emissions at 20 percent opacity to be 0.0234 (lb/10 6 BTU). The particulate emissions under the worst-case scenario are about 78 percent of the permitted emission limit. The data shows a margin for compliance with CAM. Figure 4 Figure 4 is a graph of opacity and PMIO for the Unit 2 performance testing for the baseline as well as the de-tuned ESP operating scenario at a normal generator output. The linear regression shows a worst-case scenario for particulate emissions at 20 percent opacity to be 93.06 (lb/hr). The particulate emissions under the worst-case scenario are about 30 percent of the permitted emission limit. The data shows a margin for compliance with CAM. The test data supports the propose test and cap approach using a 20 percent opacity measurement as the primary indicator to trigger both a corrective action and a excursion. In all cases the linear regression shows the opacity/mass relationship to be below both the total particulate and the PMIO emission limits. The selected indicator meet the design criteria outlined in 40 CFR Part 64. Record Keeping and Reporting Methods

All measured visible emissions readings are stored on the data acquisition and handling (DAHS) computer hard drive for five years. The DAHS computers are located in the continuous emission monitor (CEM) Page 10 of 23shelter at the base of the stack of each unit. All maintenance for the COMS is recorded in the

maintenance log in the CEM shelter. These records will include the identification of the emission unit, description of maintenance if needed, date and the name of person completing the inspection. A Semi-annual Monitoring/permit Deviation Report and a Quarterly Excess emission Report will submitted to the North Dakota Department of Health.

Page 11 of 23I. Background MINNKOTA POWER COOPERATIVE, INC. Milton R. Young Station Compliance Assurance Monitoring Plan

Fabric Filters

A. Emission Units: Lime Storage & Fly Ash Storage Description: Fabric Filter
Emission Point: M6 Location: Unit 2 Fly Ash Silo Emission Point: M7 Location: Unit 2 Lime Storage Silo Emission Point: M12 Location: Water treatment Plant Lime Storage Silo
B. Applicable Regulation, Emission Limit and Monitoring Requirements Regulation: Title V Permit Number T5-F76009, NDAC 33-15-05-01 & 33-15-03-02

Emission Limit: Opacity 20% for all emission points Particulate: M6 - 42.5 lb/hr M7 - 25.21b/hr M 12 - 4.4 lb/hr PMIO: M6 - 2.21b/hr M7 - 13.3 lb/hr II. Monitoring Approach The key elements of the monitoring approach are presented in Table 1.

Page 12 of 23Table No. 1 Monitoring Approach Fabric Filter for PM Control Emission Points: M6, M7, & M12

Indicator No. 1 I. Indicator Visible Emissions Measurement Approach Visible Emissions Check II. Indicator Range If any detectable visible emissions are noted the plant employee will notify the appropriate personnel to have the control device repaired III. Performance Criteria QA/QC Plant personnel perform visible emissions check Monitoring Frequency Daily, if system is operating during the day Corrective Action Repair as soon as practically possible MONITORING APPROACH JUSTIFICATION
I. Background Primary function is the storage of fly ash and lime. The monitoring approach outlined here applies to the fabric filters associated with the storage of fly ash and lime. The fabric filters control the particulate emissions associated with the storage of fly ash and lime. II. Justification for Selected Performance Indicators Visible emissions, was selected as a performance indicator based on our experience operating the fabric filters and the need to comply with the particulate emissions limits. Any visible sign of emissions indicates a reduction in the particulate removal efficiency of the fabric filters. III. Record Keeping and Reporting Methods All visible emissions records will be stored in the station file at the plant. These records will include the identification of the emission unit, description of maintenance if needed, date and the name of person Page 13 of 23completing the inspection. A semi-annual monitoring/permit deviation report will submitted to the North

Dakota Department of Health.

Page 14 of 23MINNKOTA POWER COOPERATIVE, INC. Milton R. Young Station Compliance Assurance Monitoring Plan

Roto-clones I. Background C. Emission Units: Coal Handling Description: Rotoclone Emission Point: M 1 Location: Unit 1 Crusher House and Conveyor 1 C Emission Point: M2 Location: Unit 1 Coal Silos Emission Point: M3 Location: Unit 2 Crusher House Emission Point: M4 Location: Unit 2 Coal Silos D. Applicable Regulation, Emission Limit and Monitoring Requirements Regulation: Title V Permit Number T5-F76009, NDAC 33-15-05-01 & 33-15-03-02 Emission Limit: Opacity 20% for all emission points Particulate: M 1 - 74.0 lb/hr M2 - 66.3 lb/hr M3 - 82.0 lb/hr M4 - 74.71b/hr PMio: M 1 - 4.3 lb/hr M2 - 7.51b/hr M3 - 18.71b/hr M4 - 18.51b/hr II. Monitoring Approach The key elements of the monitoring approach are presented in Table 1.

Page 15 of 23Table No. 1 Monitoring Approach Rotoclone for PM Control Emission Points: Ml, M2, M3 & M4 Indicator No. 1 Indicator No. 2 I. Indicator Visible Emissions Ins ection/maintenance Measurement Approach Visible Emissions Check Daily inspection according to checklist: maintenance performed as needed II. Indicator Range If any detectable visible The indicator range is water emissions are noted the plant flow through the control employee will notify the device. appropriate personnel to have the control device repaired III. Performance Criteria QA/QC Plant personnel perform Plant personnel perform visible emissions check inspections Monitoring Frequency Daily, if system is operating Daily, if system is operating during the day during the day Corrective Action 

# j Repair as soon as practically Repair as soon as practically possible possible
MONITORING APPROACH JUSTIFICATION
IV. Background Primary function of the coal handling equipment is coal crushing and delivery. The monitoring approach outlined here applies to the rotoclones associated with the coal handling equipment. The rotoclones control the particulate emissions associated with the coal handling equipment. V. Justification for Selected Performance Indicators Visible emissions, was selected as a performance indicator based on our experience operating the rotoclones and the need to comply with the particulate emissions limits. Any visible sign of emissions indicates a reduction in the particulate removal efficiency of the rotoclone.
Page 16 of 23Inspection/maintenance was selected as a performance indicator based on our experience operating the

rotoclones and the need to comply with the particulate emissions limits. A plugged drain or a poor spray pattern of water in the rotoclone indicates a reduction in the particulate removal efficiency of the rotoclone. VI. Record Keeping and Reporting Methods All visible emissions and inspection/maintenance records will be stored in the station file at the plant. These records will include the identification of the emission unit, description of maintenance if needed, date and the name of person completing the inspection. A semi-annual monitoring/permit deviation report will submitted to the North Dakota Department of Health.

Page 17 of 23Attachment B Consent Decree - July 27, 2006 Amendments to Permit No. T5476009

Page 18 of 23