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HomeMy WebLinkAbout20190730Dempsey Exhibit 3.pdfDAVID J. MEYER VICE PRESIDENT AND CHIEF COUNSEL FOR REGULATORY AND GOVERNMENTAL AFFAIRS AVISTA CORPORATTON I4I I E. MISSION AVENUE P . O. BOX 3727 SPOKANE, WASHINGTON 99220 PHONE: (509) 489-0500, FAX: (509) 495-8851 RECEIVED i0l9 J,JL 30 PIl 2: l8 i-., i- i,l.iiiLlU* r: i i rt; ilf;l,ihllssloN BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION TN THE MATTER OF THE POWER COST ) ADJUSTMENT (PCA) ANNUAL RATE ) ADJUSTMENT FILING OF AVISTA )C0RPORATTON ) CASE NO. AVU-E-L9-O9 EXHIBIT NO. TCD-3 THOMAS C DEMPSEY FOR AVISTA CORPORATION TALEN Gordon Criswell o Director, Environmental & Compliance PO Box 38 o 580 Willow Avenue o Colstrip, MT 59323 (406) 748-5002. gordon.criswell@ta lenenergy.comM O N TA N I\ September L7,2018 David L. Klemp Air Quality Bureau Chief Montana Department of Environmental Quality Sent via email to: DKlemp@mt.eov Dear Mr. Klemp, ln response to your August 3t,20t8letter requesting information related to compliance with the Mercury & Air Toxics Standard for Colstrip, the following response is provided. Each requested item identified in the 8/3U18 letter is stated first, followed by the response. 1. The daily calcrrlatiort of the u,eigltted 30-boilet operntiug day rolliug avel"ge ernission rate CVAER) tbr each of Units 1-4 as specitied byEquation 2a at $63.10009(bX2), t}onrSeptember 8,2016 to present. The calculation nnrst identi$ the eurissions {ate used tbr each uuit ancl the soruce of the 30-day total heat input (HI) tbr that trnit tbr each daily calculation. Provide a description of dre calctrlation urethoclology, ilcluding rationde tbr dre chosen nredrodology, and citation of applicable rules to iusti$ tlte rnethodology used. A. The daily calculation of the weighted 30-boiler operating day rolling average emission rate (WAER) for each of Units 1-4 as specified by Equation 2a at 63.10009(b)(2), from September 8, 2016 to September 72,2018 is provided in the attached excel spreadsheet titled Colstrip PM MATS DEQSubmittal 2018-09-17, tab DEQ ltems 1&2. Note thatthe calculation is not performed "for each of Units 1-4", but data from each of Units 1-4 is used to calculate site-wide weighted 30-day rolling average emission rate per Equation 2a and it is identified in column R. B. The emission rate used for each unit, which is the most recent MATS Method 5 stack test result for that unit for each day, is identified in columns F-1. C. The daily heat input for each unit is identified in columns J-M and the rolling 30-boiler operating day heat input for each unit is identified in columns N-Q. Note that the spreadsheet also contains heat input data from 8/9116 through 917 /t0 so that a rolling 30-day average could be caf culated starting September 8,20L6. These data are in gray cells. 2019 ldaho PCA - Dempsey Exhibit No. TCD-3 Page 1 of8 D. The relevant equation for calculating WAER is Equation 2-A from 40 CFR 63.10009. The equation as provided addresses'both calculations for pollutants using continuous monitoring (the terms that include a summation from i=1 to p, on the left side of the equation) as well as for pollutants using stack testing (on the right side of the equation). For these calculations which are based on stack testing, only the right side of the equation is relevant. ll.[&r0lsn x firn,fl r ffirClen xntr)(f;q.2a)TI'JfE =,Pr,)t + E?rfitit Where: llerr = hourly emlsslon ra,te (e.o.. ltvMMBbu. lh,'}11!'h) fronr unlt I'E CEMS for t'he pre- cedlng 80-croup botl€r opgraclns days, R.nrr = hourly heat tnput or gnosE output fronr unlt I for th€ precedlnc glgroup bouer opemtlnr dave. p = nurnbBr of EOLis tn smlsslonB averaglng sroup t'h&t roly on CDME or sorbsnt trap monltorlnE. n = number of hours thet hourly r&tas arg collected over SGsoup bollor operattnf days. t'er, = gploloni rate from rnoEt rcc€nG eml6- slons test of unlt, I ln tsrms of lhteab ,npu[ or thtross output. Rh = Total beat lnput or grors outpuL of unltt for Ehe precedlnr il0-Dotler op€ratlns dal's. arrd m = number of EGUs ln emls8lons aysraglnE rroup that rels on emisslons tostlng. a. The numerator i. First multiplies two terms 7. Teri, the unit-specific emission rate from the most recent emissions test in lblMMBtu 2, Rti, the unit-specific heat input in MMBtu for the preceding 30 boiler operating days 3. The product of which equals mass emissions for that unit (lbs.) ii. Then sums the mass emissions for each unit across the four units b. The denominator is simpler and just sums Rtifor each unit across the four units (MMBtu's) E, The 30-boiler operating day heat input is developed consistent with the definition in 40 CFR 63.10042. Boiler operating day means a 24-hour period that begins ot midnight and ends the following midnight during which ony fuel is combusted ot any time in the EGU, excluding startup periods or shutdown periods. lt is not necessary for the fuel to be combusted the entire 24-hour period. a. Boiler operating day is determined using hourly data for each unit b. Hours when the unit is in startup or shutdown are excluded consistent with the definition c. To determine whether any fuel is combusted, both heat input and power output values are reviewed on an hourly basis. ln a day, if there is an hour that is not startup or shutdown which has a non-zero value for either power output or heat input (or both), that day is a boiler operating day. d. The 30-boiler operating day heat input value for a unit is calculated by summing the calculated daily heat input values for the current (or most recent) boiler operating day plus the 29-preceding boiler operating days. 2019 ldaho PCA - Dempsey Exhibit No. TCD-3 Page 2 of 8 2. Records of the daily heat input (HI) tbt each of Units 1-4 ti'onr Septernbet 8,2076 to preseut. Pleasc cleatly denronstrate hov, drese daily HI valtres are used in calculatirlg the \i/AER. The daily heat input (Hl) for each of Units 1-4 from September 8, 20L5 to September 12, 2018 is also provided in the attached spreadsheet columns J-M. A daily heat input value is presented for a unit, if there was at least one hour of non-startup/shutdown heat input within that day. Each day's calculated 30-boiler operating day (BOD) heat input for a unit (in columns N-Q for Units L-4, also referred to as Rti in equation 2a, is the total of the preceding 30 heat input values for the unit corresponding to the unit's preceding 30 boiler operating days (i.e., the last 30 days when there is at least one hour of operations under non-startup/shutdown condition). To sum values for the preceding 30 boiler operating days for a unit, the 30 boiler operating days do not have to be consecutive. 3. Records of the occuuelrce and dtuatiou of each starnrp and/or shut do*,u tbt each of Units 1-4 ti'orn Septernber 812016 to present. Provide a natrative description of horvTaleu conrplies with the 'nvodr practice standards of N{ATS durirg these occtrlrences and denronstrate how drese situations ate addressed in the WAER calculations. The occurrence and duration of each startup and/or shut down for each of Units 1-4 from September 8, 2016 to September 12,20t8 is provided in the attached spreadsheet titled Colstrip PM MATS DEQ Submittal 20L8-09-17, tab DEQ ltem 3. The data in thls tab are on an hourly basis and each startup and/or shut down hour is identified by a 1 designation. Unit 1 startup times are found in column E and Unit 1 shut down times are found in column D. Unit 2 startup tirnes are found in column I and Unit 2 shut down times are found in column H. Unit 3 startup times are found in column M and Unit 3 shut down times are found in column L. Unit 4 startup times are found in column Q and Unit 4 shut down times are found in column P. The Colstrip Steam Electric Station complies with the MATS work practice standards during startup and shut down by taking the following actions: All Continuous Emission Monitoring Systems (CMS) are operated during startup and shut down periods. Clean fuel, Liquefied Petroleum Gas (LPG) for Units 1&2 and Low Sulfur #2 Diesel Fuel Oil for Units 3&4, are used for startup. When firing on coal, all the applicable control technologies (Low-NOx systems, Mercury Control systems, and Wet Venturi Scrubber systems) are in operation. Records of startup/shut down periods are maintained. Dates of most recent boiler tune-ups and burner inspections are provided in the MATS Serni- annual Reports submitted to MDEQ. Periods of startup and shut down are not included in the site-wide weighted average emission rate (wAER). 2019 ldaho PCA - Dempsey Exhibit No. TCD-3 Page 3 of 8 4. A description of all non-rotrtirre rvor* peltbnned, any operatioual changes, arxl any chauges to the coal supply or quality at Units 3 and 4 tbr the period between the tbumh quartet 2017 and the second qualter 2018 drat nray have irnpacted the Pi\{ errrissious pertbmrance. A review of activities from 4ft quarter 2OL7 lo 2nd quarter 2018 was conducted with engineers, operations, and.maintenance; including the boiler and scrubber crews, to get a thorough understanding of any changes that may have impacted the PM emissions performance. Coal supply or quality - all coal burned from 4th quarter 2017 through 2nd quarter 2018 were from the normal permitted mine areas. Coal quality analysis was reviewed including ash content, heating value, moisture, sulfur and ash characteristics. The coal quality varied during this period but was within contract specifications. Relevant work and Operational changes between 4th quarter 2077 and 2nd quarter 2018 Scrubber makeup water (pond return wafer) increased in solids concentration for two reasons; o Pond return level (3&4 EHP B Cell) was low due to forced evaporation of pond water during 2Ot7 to eliminate water in the ash ponds and help ensure protection of groundwater. This level was raised to provide required make-up volume by transferring water from the 3&4 EHP F Cell which contained higher solids. o Additional water was transferred from the 3&4 EHP F Cell (higher solids) to pond return (3&4 EHP B Cell) to facilitate liner repairs at the 3&4 EHP F Cell and help ensure protection of groundwater. Low-NOx tuning at Units 3&4 boilers - optimizing the SmartBurn Low-NOx system to rninimize NOx emissions. Although neither the continuous Opacity Monitors nor the PM CEMS provided an indication of an increased PM emission level across the time frame indicated, it appears that the characteristics of the PM had changed. The change, potentially the particle size distribution in the stack, appears to have changed the ratio of PM mass to detected concentration, i.e., the correlation curve of the PM CEMS. ln other words, particles of a different size with more total mass may have been emitted, but the Opacity Monitors and PMCEMS were still "seeing" the same concentration in the stack gas. Colstrlp is still investigating this issue to determine what could be done to prevent it from happening in the future. 2019 ldaho PCA - Dempsey Exhibit No. TCD-3 Page 4 of 8 5. A description of all iuspection, rnaintenance, and operation activities associated rvith the boilers and verrturi scrubbers since dre deviations. Quarterly MATS PM Test results were received on June 28,20L8 that indicated a deviation of the MATS PM limit. MDEQ was notified on June 28 and Unit 3 was removed from service on June 28 and Unit 4 was removed from service on June 29. Talen proposed and MDEQ acknowledged that llmited operation of Units 3&4 for evaluation of a corrective action or for data gathering related to potential corrective action was a prudent approach to solving the issue. An extensive inspection of the Units was conducted including the coal mills, boiler, ductwork, air preheater, scrubbers, and the stack. Cleaning, adjustments, and repairs were conducted as needed. Areas of inspection included: CoalMills Classifiers Air flow controls Windboxes Separated Over Fire Air (SOFA) dampers Top Over Fire Air (TOFA) dampers Burners Ductworko Air Preheater o Scrubber inlet ducts o Scrubber outlet ducts Scrubbers Venturi/Plumb Bob area Venturi/Plumb Bob sprays Venturi & Absorption pumps Absorption sprays Wash Trays Wash Tray sprays Mist Eliminators Mist Eliminator sprays Reheaters Reheater soot blowers liner Unit 3 was off from June 28 - July 8 for this work, Unit 4 was off from June 29 - July L7 for this work. No major equipment issues were identified during these outages. Additional outages and inspections continued to occur as needed during the trouble shooting period as corrective actions were evaluated and implemented. o o er o o o o Boil o o o o o o o o o o Stack o 2019 ldaho PCA - Dempsey Exhlbit No. TCD-3 Page 5 of I Four main areas were investigated to determine and address the cause of the 2nd quarter MATS PM test results on Units 3&4: Compliance Test Method FuelQuality Boiler Combustion Scrubber Performance Nationally recognized expertise was brought on-site to help conduct the investigation and implement corrective actions: AECOM - overall root cause investigation & scrubber expertise GE/Alstom - boiler combustion expertise SmartBurn - boiler combustion expertise Power Technical Services - boiler combustion expertise Munters - scrubber mist eliminator expertise Bison Engineering - stack testing expertise Air Control Techniques - stack testing & pollution control expertise Compliance Test Method Qualified Source Testing lndividuals (QSTI Certified) conducted the PM tests. They verified that the proper method, procedures, QA/QC, and calculations were used. An audit of the testing was conducted following the EPA Air Emissions Testing Body (AETB) Manual. lndependent side-by-side testing was conducted for single run tests, with consistent results between test groups. FuelQuality Coal analysis including proximate analysis and ultimate analysis was reviewed. While variations in coal quality were observed, the results were within contract specifications. Boiler Combustion Coal mill performance was evaluated and compared to target guidelines related to coal grind (fineness) as well as fuel distribution in the boiler. Minor adjustments were made to some mills to rneet the target guidelines. Some fouling/slagging was observed in the boiler which was cleaned up and adjustments and minor repairs were made to the furnace to help reduce slagging/fouling. Boiler conditions were evaluated and adjusted to establish a focus on overallfurnace condition compared to the low-NOx focus that had recently occurred. Boiler conditions were also evaluated to ensure excess SO3/acid mist, a condensable PM that could affect the results, was not being formed and emitted. Scrubber Performance The entire scrubber system from the inlet ductwork to the stack were inspected. Cleaning, adjustments, and repairs were completed as necessary. Evaluation of scrubber performance focused on three maln areas - liquid spray flow, flue gas flow, and scrubber chemistry. 2019 ldaho PCA - Dempsey Exhibit No. TCD-3 Page 6 of 8 Liquid spray flow - the wet venturi scrubbers remove both particulate and SO2 and proper spray flow to the different sections of the scrubber are important, The scrubber sprays include the venturi sprays, plumb bob sprays, absorption sprays, wash tray sprays, and mist eliminator sprays. All sprays were inspected and evaluated during operation to verify proper spray. Adjustments were made (flow orifices installed) to the venturi/plumb bob sprays to provide a more effective balance of sprays in this area. This venturi/plumb bob section of the scrubber is where most of the particulate removal occurs. Flue gas flow - overall flue gas flow and proper distribution of the flue gas is important to etfective scrubber operation. The mist eliminator section of the scrubber controls carry-over of droplets from the wet scrubbing process. These droplets contain solids which can contribute to particulate emissions. Testing of the mist eliminator section of the scrubber indicated that, although meeting manufacturer specifications, flue gas flow through the mist eliminators was not optimally balanced, resulting in areas of higher flows. A mist eliminator flow distribution plate was installed on all scrubbers to better balance the flue gas flow through this area of the scrubber and help keep velocities at a level for proper mist eliminator performance. A more detailed description of this work is described in the De Minimis Notification for Changes to Colstrip Units 3&4 Scrubbers - Scrubber Flow Distribution Plates that was submitted to MDEQon August 24,2018 (this notification is attached). Scrubber Chemistry - A review of scrubber chemistry, primarily scrubber solids, was conducted to evaluate previous levels in comparison to current levels. There are two separate scrubber water supplies that were evaluated, scrubber recycle tank water and scrubber wash tray water. Historic levels of scrubber recycle tank solids range from 25-30% solids. Levels in early 2018 were up to 35% solids. Historic levels of scrubber wash tray solids range from LO-!S% solids. Levels in early 2018 were up to 17% solids. Testing of scrubber chemistry indicates that a target of 20-25% recycle tank solids and L0- 15% wash tray solids is good point that balances the benefits of lower solids in regards to carry-over and PM emissions with the benefits of higher solids that help prevent scale buildup which results in equipment shutdown for cleaning. Scrubber additives were also tested to determine if scrubber performance could be improved, with the results from that testing indicating little to no improvement in scrubber performance. 6. Records of the date and tinre (start and errd) tbr each period of norrcompliancc ftom.|true 21, 2018 to pr-esent. MATS PM Deviations are recorded for daily rolling 30-day site-wide average above 0.030 lb/mmbtu from June 21, 2018 through September 5,20t8. Data provided in response to Request for lnformation #1 shows compliance with the site-wide MATS PM limit from September 6,2078 to present. Unit 4 MATS PM Compliance Test conducted on 9/61t8 demonstrated a PM emission rate of 0.02L f b/mmbtu. Unit 3 MATS PM Compliance Test conducted on 911U1,8 dernonstrated a PM emisslon rate of 0.O24lblmmbtu. 2019 ldaho PCA - Dempsey Exhibit No. TCD-3 Page 7 of 8 lf you have any questions regarding this response to your information request, please don't hesitate to contact me at 406-748-5002 or sordon.criswel l@talenenersv.com. Sincerely, ;{o*^ h,.*t{ Gordon Criswell Director, Environmental & Compliance Talen Montana 2019 ldaho PCA - Dempsey Exhibit No. TCD-3 Page 8 of 8