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5.2 ERMUSR 04-08-20254r.;, Elk Riv Municipal Utilities UTILITIES COMMISSION MEETING TO: FROM: ERMU Commission Mike Tietz— Technical Services Superintendent MEETING DATE: AGENDA ITEM NUMBER: April 8, 2025 5.2 SUBJECT: 2024 Annual Reliability Report ACTION REQUESTED: Receive the 2024 Annual Reliability Report BACKGROUND: Minnesota Rules Chapter 7826 Public Utilities Commission Electric Utility Standards cover safety, reliability, service, and reporting requirements. Per 7826.0100(A), municipal utilities are exempt from these requirements. However, the Elk River Municipal Utilities Commission adopted several parts of this chapter as a Distribution Reliability Standard policy requiring annual reporting on system reliability. DISCUSSION: In 2024, our reliability index numbers remained impressive. These reliability index numbers demonstrate the condition of our solidly built electrical system as well as the excellent response times our line crews provide. The utility's commitment to accountability, long term visioning of system design, and ongoing system maintenance are also reflected by these numbers. The table below reflects the number of customer outage minutes for the last 10 years. Year # of Customers # of Outage Minutes # of Outages 2015 9449 225,337 41 2016 10862 432,310 59 2017 11489 354,625 40 2018 12158 117,055 51 2019 12463 312,885* 59 2020 12604 197,884 51 2021 13038 628,670 61 2022 13228 174,500 50 2023 13543 187,469 51 2024 13797 575,509 43 *118,978 of these minutes are due to two separate transmission outages. Page 1 of 3 170 Listed below are several reliability indices that are used within the electric industry to make it easier to compare performance among utilities along with ERMU's 2023 and 2024 statistics. Average Service Availability Index (ASAI) ASAI is a measure of the average availability of the sub -transmission and distribution systems to serve customers. It is the ratio of the total customer minutes that service was available to the total customer minutes available in a time period. This is normally expressed as a percentage. ERMU's 2024 ASAI is 99.992% Availability ERMU's 2023 ASAI is 99.9973% Availability Customer Average Interruption Duration Index (CAIDI) CAIDI is defined as the average duration (in minutes) of an interruption experienced by customers during a specific time frame. It is calculated by summing the customer minutes off during each sustained' interruption in the time period and dividing this by the number of customers experiencing one or more sustained' interruptions during the time period. The resulting unit is minutes. The index enables utilities to report the average duration of a customer outage for those customers affected. ERMU's 2024 CAIDI is 118.931 minutes ERMU's 2023 CAIDI is 84.827 minutes System Average Interruption Duration Index (SAIDI) SAIDI is defined as the average interruption duration (in minutes) for customers served during a specified time period. It is determined by summing the customer minutes off for each sustained' interruption during a specified time period and dividing that sum by the average number of customers served during that period. The resulting unit is minutes. This index enables the utility to report how many minutes' customers would have been out of service if all customers were out at one time. ERMU's 2024 SAIDI is 42.083 minutes ERMU's 2023 SAIDI was 14.077 minutes System Average Interruption Frequency Index (SAIFI) SAIFI is defined as the average number of times that a customer is interrupted during a specified time period. It is determined by dividing the total number of sustained' interrupted customers in a time period by the average number of customers served. The resulting unit is "interruptions per customer." ERMU's 2024 SAIFI is 0.354 ERMU's 2023 SAIFI was 0.166 ' Only outages lasting longer than five minutes are included in the calculations, as defined by IEEE 1366. Page 2 of 3 171 Staff review these statistics in detail to find ways to continually improve our system. These statistics are very good when compared with other utilities. As indicated by the following pie chart and statistics list, you can see the causes of the outages experienced in 2024. Other Outage Cause Count View 12% 16 0 Bird 2% Squirrel 11 0 Overhead 2% Vehicle Accident 4 m Wildlife Tree 5% 37% Equipment 3 m Wildlife 2 0 Equipment Overhead 1 m 7% _ Bird 1 0 Non -Utility Excavation 1 0 Vehide Accident Underground 1 0 9% Lightning 1 0 Wind 1 0 Utility Human Error 1 0 Squirrel 2696 Total 43 Many investor -owned and cooperative run utilities "storm normalize "their reliability numbers by removing "major outages" due to storms from their reliability index number calculations. Our reliability numbers have not been storm normalized. Our numbers reflect these major outages and represent what our customers experienced in 2024. Overall, our electric distribution system is very resilient, and our system reliability remains excellent. Please receive the attached American Public Power Association's (APPA) eReliability Annual Report which contains published averages that can be used to better understand the performance of our electric system relative to other utilities nationally and to those within their region or size class. ACTION REQUESTED: Staff requests the Commission receive and file the APPA eReliability Tracker 2024 Annual Report for Elk River Municipal Utilities. ATTACHMENT: • APPA eReliability Tracker 2024 Annual Report for Elk River Municipal Utilities Page 3 of 3 172 %n(-l)-q Elk River Municipal Utilities '* ANNUAL 0 BENCHMARKING N REPORTTRR""BKER American Public Power Association A M E R I CA N DErljPUBLIC W.-E . RESEARCH & DEVELOPMENT ASSOCIATION Powering strong communities 173 I. About This Report This report focuses on distribution system reliability across the country and is customized to each utility that participates in the American Public Power Association's eReliability Tracker f etvitm. APPA created the eReliability Tracker Annual Report to assist utilities in their e understand and analyze their electric system. In 2012, APPA developed the eReliability Tracker fftffm*De\aetppntEfntOD15E[)emonstration of Energy & E program. Ebds dz0a time eReliability Tracker from January 1, 2024 to December 31, 2024 EbO�youalytil togibb gsriifgedyde not have a full year of data in the system. The report includes data recorded as of February 25, 2025. fledsalbdttylnestoric and ongoing engineering investment decisions within a utility. Proper use of reliability metrics ensures that a utility is performing its intended function and is ffctivildringrseev.ice in a consistent and e While the primary use of reliability statistics is for self -evaluation, you can use these statistics ff6armQ�a�ar�lycsralt�}i�c�liiiir utilities. However, di fiamation, ambient environment, weather conditions, and number of customers served typically limit most utility -to -utility comparisons. Due to the diverse range of utilities that use the eReliability Tracker, this report endeavors to improve comparative analyses by grouping utilities by size and region. Since this report contains data for all utilities that use the eReliability Tracker, it is important to €fatiE;bJBphwM ticbWidyidar�ae3sEmall utility can a the issues associated with comparability, each utility's reliability statistics are weighted based on customer count when aggregated. This means that all utilities are equally weighted, and all individual statistics are developed on a per customer basis. EHERRO@4regate statistics in this report are calculated from the 350 utilities with veri outage data. Utilities that experienced no outages in 2024, or did not upload any data, will 6altd,vD�eetia�rir`i@I'udas� in their report for utility-speci the aggregate analysis. Also note that log -normal data with a z-scoreM greater than 3.25 may i<y Widt&1f ith9j jgregate statistics. f*� kaFec me: mnd atfeartiostxnoebmzsiolorpaifiBa5 indicates that the data point is three and one -quarter standard deviations from the mean. A z-score of 0 indicates that the data point is identical to the mean. 174 dd1hyClassi This report separates utilities into groups according to geographic region and the number of customers served. Table 1 shows the range of customer counts for utilities that use the >iilRdiaM4gTrnmaoerobppproximately 107 utilities per group. Your utility is in size class bnd region 3 Table 1. Customer count range per size class Customer Count Range Class 1 >0 Class 2 >1,527 Class 3 >3,582 Class 41 >7,526 Class 5 >14,528 Each utility is also grouped with all other participating utilities within their region. Figure 1 shows the number of utilities using the eReliability Tracker in each region and Figure 2 shows the states and territories included in each region. Figure 1. Number of utilities subscribed to the eReliability Tracker by region 140 120 Ln N 4- 100 L 4 80 - O (U 60 E Z) 40 Z 20 0 Regions 175 Figure 2. Regions r- AMERICAN GUAM NORTHERN PUERTO U.S. VIRGIN SAMOA MARIANA RICO ISLANDS ISLANDS REGION 8 176 II. IEEE Statistics I imithmtnet;i=ee1iability, the industry standard metrics are de Electrical and Electronics Engineers' Guide for Electric Power Distribution Reliability Indices, or IEEE 1366 guidelines. For each utility, the eReliability Tracker performs IEEE 1366 calculations for System Average Interruption Duration Index (SAIDI), System Average Interruption Frequency Index (SAIFI), Customer Average Interruption Duration Index (CAIDI), Momentary Average Interruption Frequency Index (MAIFI), and Average Service Availability Index (ASAI). It is important to note how major events (MEs) are calculated and used in this report. An example of an ME includes severe weather, such as a tornado or hurricane, that leads to unusually long outages in comparison to your distribution system's typical outage. This report uses the A9113hAlVdium ftildctly on the SAIDI for speci rather than a daily SAIDI. The APPA ME threshold allows a utility to remove outages that exceed the IEEE 2.5 beta threshold for outage events, which considers up to 10 years of the utility's outage history. In the eReliability Tracker, if a utility does not have at least 36 outage events prior to the year being analyzed, then no threshold is calculated. If this is the case for OWiatudilfbft tiabul,,ectiomlh idveutNULL value in the following MEs in the SAIDI, SAIFI, CAIDI, and ASAI sections of this report will be the same as the calculations with MEs for your utility. More outage history will provide a better threshold for your utility. VvA&dtifity's APPA major event threshold is For each of the reliability indices, this report displays your utility's metrics alongside the mean values for all utilities using the eReliability Tracker and within the same class and region as gk=btdivyi.tft-eeach of the following subsections allows you to better understand the performance of your electric system relative to other utilities nationwide and to those within your same region or size class. The second table breaks down the national data into quartile ranges, a minimum value, and a maximum value. All indices, except MAIFI, are calculated for outages with and without MEs. Furthermore, the tables show indices for scheduled and unscheduled outages. Note that scheduled and unscheduled calculations include MEs. Also note that wherever MEs are excluded, the exclusion is based on the APPA ME threshold for your system. 177 II.1. System Average Interruption Duration Index SAIDI is the average duration (in minutes) of an interruption per customer served by the utility f NffiMfrwpeci &rrrdrSM(E9 is a sustained interruption index, only outages lasting longer than are included in the calculations. SAIDI is calculated by dividing the sum of all customer minutes of interruptioni2�SdittlirinafronpaLby the average number of customers served during that period. For example, a utility with 100 customer minutes of interruption and 100 customers would have a SAIDI of 1. Note that in the tables below, scheduled and unscheduled calculations include MEs. Also note that wherever MEs are excluded, the exclusion is based on the APPA ME threshold for your system. T&Wmg.e SAIDI with and without MEs In minutes All No MEs Unscheduled Scheduled Your utility 42.08 9.8 42.08 NULL Utilities that use the eReliability Tracker 120.3 54.49 113.49 13.19 Utilities in your region 50.0 32.24 48.83 3.0 Utilities in your size class 96.25 39.74 93.5 4.31 16abteT3ary SAIDI data from the eReliability Tracker In minutes All No MEs Unscheduled Scheduled Minimum 0.08 0.08 0.08 <0.01 First Quartile 19.39 11.07 18.77 0.19 Median 44.37 26.79 40.95 1.24 Third Quartile 131.4 55.66 127.24 5.03 Maximum 1,639.92 776.98 1,634.25 629.54 [2]: Customer minutes of interruption is calculated by multiplying total customers interrupted and total minutes of interruption. 178 Figure 3. Average SAIDI by region 350 Ln Q1 + 300 7 C r- 250 M 200 5 Regions 179 II.2. System Average Interruption Frequency Index SAIFI is the average instances a customer on the utility system will experience a sustained fn&numduring a speci &nrrd MR isre sustained interruption index, only outages lasting longer than included in the calculations. SAIFI is calculated by dividing the total number of customers that experienced sustained interruptions by the average number of customers served during that period. For example, a utility with 150 customer interruptions and 200 customers would have a SAIFI of 0.75. Note that in the tables below, scheduled and unscheduled calculations include MEs. Also note that wherever MEs are excluded, the exclusion is based on the APPA ME threshold for your system. T&Wm4e SAIFI with and without MEs In interruptions All No MEs Unscheduled Scheduled Your utility 0.35 0.14 0.35 NULL Utilities that use the eReliability Tracker 0.78 0.54 0.75 0.06 Utilities in your region 0.52 0.4 0.51 0.03 Utilities in your size class 0.65 0.43 0.63 0.03 %ytefrSary SAIFI data from the eReliability Tracker In interruptions i All No MEs I Unscheduled IScheduled Minimum <0.01 <0.01 <0.01 <0.01 First Quartile 0.21 0.14 0.19 <0.01 Median 0.54 0.36 0.53 0.01 Third Quartile 1.16 0.77 1.1 0.04 Maximum 3.63 2.43 3.63 2.32 :1 Figure 4. Average SAIFI by region 1.2 Ln c 0 1.0 Q 0.8 0.6 LL Q N 0.4 0) ra i U1 0.2 Q 0.0 5 Regions 181 II.3. Customer Average Interruption Duration Index CAIDI is the average duration (in minutes) of an interruption experienced by customers during a fil&de frame. &nrrejrCL#1RI is a sustained interruption index, only outages lasting longer than are included in the calculations. CAIDI is calculated by dividing the sum of all customer minutes of interruption by the number of customers that experienced one or more #viBrduptjuersadierQngtdmt-perapdr.iThi emetric re (minutes of duration) during an outage. Note that in the tables below, scheduled and unscheduled calculations include MEs. Also note that wherever MEs are excluded, the exclusion is based on the APPA ME threshold for your system. ltaWEage CAIDI with and without MEs In minutes All No MEs Unscheduled Scheduled Your utility 118.93 67.46 118.93 NULL Utilities that use the eReliability Tracker 135.22 92.4 138.62 153.96 Utilities in your region 95.65 83.74 95.41 105.79 Utilities in your size class 1143.62 86.471 143.611 157.41 Tatbtei7ary CAIDI data from the eReliability Tracker In minutes All No MEs Unscheduled Scheduled Minimum 11.21 11.21 10.52 7.82 First Quartile 62.85 51.38 62.41 61.8 Median 93.56 81.55 93.94 95.16 Third Quartile 143.73 110.8 144.19 162.66 Maximum 1,923.68 402.94 2,012.24 1,899.69 182 Figure S. Average CAIDI by region 7200 v C E 150 U 100 QJ cn (0 ? 50 Q 5 Regions 183 II.4. Momentary Average Interruption Frequency Index MAIFI is the average number of momentary interruptions a utility customer will experience during a filerie frame. V�natJi$taksiuith a duration of MAIFI is calculated by dividing the total number of customers that experienced momentary interruptions by the total number of customers served by the utility. For example, a utility with 20 momentary customer interruptions and 100 customers would have a MAIFI of 0.20. ffl&nbeittacy inrndruCiPtieaYvWmbtancffetdmated outage management system might not log these interruptions; therefore, some utilities have a MAIFI of zero. im§.e MAIFI In interruptions Your utility Utilities that use the eReli Utilities in your region Utilities in your size class All NULL Tracker 0.45 0.7 0.66 Tabte-Sary MAIFI data from the eReliability Tracker In interruptions All Minimum <0.01 First Quartile <0.01 Median 0.06 Third Quartile 0.53 Maximum 5.0 Figure 6. Average MAIFI by region 0.7 0 0.6 a-� Q 7 i 0.5 U1 a-� 0.4 LL 0.3 0.2 i j 0.1 Q 0.0 5 Regions 185 II.5. Average Service Availability Index ASAI is the percentage of time the sub -transmission and distribution systems are available to serve fid§#wrfev rcturing a speci This load -based index represents the percentage availability of electric service to customers within the period analyzed. It is calculated by dividing the total hours in which service is available to customers by the total hours that service is demanded by the customers. For example, an ASAI of 99.99% means that electric service was available for 99.99% of the time during the given period. Note that the higher your ASAI value, the better the performance. In the tables below, scheduled and unscheduled calculations include MEs. Also note that wherever MEs are excluded, the exclusion is based on the APPA ME threshold for your system. Table 10. Average ASAI with and without MEs In percentage All No MEs Unscheduled Scheduled Your utility 99.992 99.9981 99.992 NULL Utilities that use the eReliability Tracker 99.9775 99.9898 99.9787 99.9976 Utilities in your region 99.9905 99.9939 99.9907 99.9994 Utilities in your size class 99.9817 99.9924 99.9823 99.9991 Table 11. Summary ASAI data from the eReliability Tracker In percentage All I No MEs Unscheduled Scheduled Maximum 99.9999 99.9999 99.9999 99.9999 First Quartile 99.9963 99.9978 99.9964 99.9999 Median 99.9916 99.9949 99.9922 99.9997 Third Quartile 99.9755 99.9894 99.9765 99.999 Minimum 99.6888 99.86 99.6899 99.8856 Figure 7. Average ASAI by region 100.000 Q 99.975 m C 99.950 UJ u N 99.925 a Q99.900 Ln Q 99.875 N En 99.850 v 99.825 99.800 5 Regions 187 II.6. Energy Information Administration Form 861 Data Form EIA-861 collects annual information on electric power industry participants involved in the generation, transmission, distribution, and sale of electric energy in the United States and its territories. In 2014, Energy Information Administration (EIA) began publishing reliability statistics in Form EIA-861; therefore, APPA included these statistics in this report for informational purposes. Please note that the following data includes 174 investor -owned, 467 rural cooperative, and S2J-hptNodifL0bE4Ar8ft1lities that were large enough to be required to form. The statistics do not include data from utilities that complete the EIA 861-5 form, which smaller entities complete. Note that the 327 participating public power utilities include fid IAJasinunicipal, political subdivision, and state. In addition, since the collection and release of EIA form data lags by a year, the data is based on 2023 data that was published October 10, 2024. Therefore, we suggest you only use the aggregate statistics contained herein as an informational tool for further comparison of reliability statistics. In Form EIA-861, an entity provides SAIDI and SAIFI including and excluding ME days in accordance with the IEEE 1366-2003 or IEEE 1366-2012 standard. Although EIA collected other reliability -related data, the tables below only include SAIDI and SAIFI data including and excluding ME days. You can download the full set of data at: www.eia.gov/electricity/data/eia861 /. Table 12. Your utility's SAIDI and SAIFI with and without IEEE ME days SAIDI with IEEE ME SAIDI without IEEE SAIFI with IEEE ME days SAIFI without IEEE ME days (minutes) ME days (minutes) interruptions) days (interruptions) 42.08 9.48 0.35 0.14 Table 13. Summary SAIDI data from Form EIA-861, 2023 In minutes Average All No MEs 376.90 149.41 Minimum 0.20 0 First Quartile 80.88 51.59 Median 178.01 101.18 Third Quartile 392.12 175.32 Maximum 10,820.00 2,475.09 Table 14. Summary SAIFI data from Form EIA-861, 2023 In interruptions All No MEs Average 1.71 1.26 Minimum 0.01 0 First Quartile 0.82 0.60 Median 1.30 0.99 Third Quartile 2.14 1.54 Maximum 17.38 16.92 M0 III. Outage Causes Equipment failure, extreme weather events, wildlife, and vegetation are some of the most common causes of electric system outages. The following pie chart shows the percentages of the primary causes of outages for all utilities using the eReliability Tracker in 2024. Vdeather -"v 19.3°/a Equipment 21.2% VVildlife 16.4% 0.7% Utility Human Error 1.2% Power Supply 4.4% Public 9.7% 16.2% Unknown 11.0% Vegetation r Scheduled Figure 8. Primary causes of outages in 2024 Certain factors, such as regional weather and animal/vegetation patterns, can make some bajnm.Ep 6rAiptiEel-Ehefotlevftisection includes graphs depicting common causes of outages for your utility, all utilities in your region, and all utilities using the eReliability Tracker. @ifwi es: rmtaining aggregate information are customer -weighted to account for di utility size for a better analytical comparison. For example, a particularly large utility may have a large number of outages compared to a small utility. To avoid skewing the data toward large utilities, the number of cause occurrences is divided by customer size to account for the €fi-ences. In Figures 9 to 14, the data represent the number of occurrences for each group 190 of 1,000 customers. A customer -weighted occurrence rate of I" means an average of one outage from that cause occurred per 1,000 customers in 2024. Note that the sustained outage cause analysis is more comprehensive than the momentary outage cause analysis due to a larger and more robust sample size for sustained outages. Regardless, tracking both sustained and momentary outages helps utilities understand and reduce outages. To successfully use the outage information tracked by your utility, it is imperative to classify and record outages in detail. The more information provided per outage, the more conclusive and practical your analyses will be. 191 IIIA. Sustained Outage Causes In general, sustained outages are the most commonly tracked outage type. In analyses of sustained outages, utilities tend to exclude scheduled outages, partial power, customer - related problems, and qualifying major events from their reliability indices calculations. While this is a valid method for reporting, these outages should be included for internal review to make utility -level decisions. In this section, we evaluate common causes of sustained outages for your utility, corresponding region, and for all utilities that use the eReliability Tracker. It is NPor"atrl�norttelbadtagetaghat] Iasnages are classi b gll lg(e Figure 9ADpauses of sustained outages for all utilities that use the eReliability Tracker 2.5 0 0 O 2.0 () d 1.5 a) V C 1.0 7 u u O 0.5 0.0 Outage Cause Types €Fe patesMof sustained outages for your utility [31 1.2 - o 1.0 0 a i 0.8 (J a O 0.2 0.0 - 1.17 0.81 0.22 0.15 Tree Squirrel Vehicle Accident Equipment Wildlife Outage Cause Types [3]: The number of occurrences for each cause is divided by the utility's customer count (in thousands) to create an occurrence ffitwithl#tl4rsiae2ompared across di 192 €ikjoatest4.of sustained outages in your region 20,40 20.0 O 17.5 0 15.0 L a 12.5 V 10.0 C N 7.5 7 u 5.0 270 � . 2.5 1.23 0.0 Non -Payment Utility Maintenance and Repairs Squirrel Weather Tree Outage Cause Types 193 III.2. Momentary Outage Causes Mkt eb&ptraitWk m me iltaByysbutugdmtan be di due to the hazard they pose for electronic equipment, it is important to track and analyze the causes of momentary outages. This section evaluates the common causes of momentary outages for your utility, region, and size class as well as common causes for all utilities that faeafthreiI4�bEility Tracker. Please note that only outages lasting less than #iW0ffiyrMfrUefflMy,,I&bWyures 12 number of occurrences for each cause is divided by that utility's customer count (in ffrreatarbidtYt6ze3--ate an occurrence rate that can be compared across di € Ejpmes*2.of momentary outages for all utilities that use the eReliability Tracker 0.s p 0.7 0 0. 0.6 L U 0.s u 0.4 C N � 0.3 UU 0.2 0 0.1 0.0 Equipment Replacement Other - Vegetation Non -Payment Utility Maintenance and Repairs Unknown Outage Cause Types €nes43.of momentary outages for your utility 0.04 O O O rl 0.02 N PLO 0.oa 0.000 0.000 0.000 0.000 0.000 V C N L -0.02 U U 0 —0.04 None None None None None Outage Cause Types 194 €kjpntisN.of momentary outages in your region o, 0 0 6 L W a5 U u 4 c a� i 3 V U 2 0 345 0.55 0.54 0.37 Non -Payment Unknown Heat Storm Manufacturing Defect Outage Cause Types 195 Thank you for your active participation in the eReliability Tracker service. We hope this report is useful to your utility in analyzing your system. If you have any questions regarding the material provided in this report, please contact: APPA's Reliability Team Paul Zummo Ji Yoon Lee Matthew Atienza Gregory Obenchain Reliability@PublicPower.org For more information on reliability, visit https://www.publicpower.org/reliability-tracking Copyright 2025 by the American Public Power Association. All rights reserved. 196 AMERICAN PUBLIC p%'��R® ASSOCIATION Powering Strong Communities 2451 Crystal Drive Suite 1000 Arlington, VA 22202-4804 www.PublicPower.org #PublicPower