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Home My WebLink AboutStaff Report 2606-64912.Calendar Year 2025 Reliability Metric Update and Annual System Reliability Goal Setting; CEQA status: Not A Project, CEQA Guidelines section 15378(b)(5). (ACTION: 6:35PM – 7:35PM) Staff Presentation Item No.2 Page 1 of 4 Utilities Advisory Commission Staff Report From: Alan Kurotori, Director Utilities Lead Department: Utilities Meeting Date: August 5, 2026 Report #: 2606-6491 TITLE Calendar Year 2025 Reliability Metric Update and Annual System Reliability Goal Setting; CEQA status: Not A Project, CEQA Guidelines section 15378(b)(5). RECOMMENDATION Receive Calendar Year 2025 Reliability Metrics and Provide Recommendations for Annual System Reliability Goals EXECUTIVE SUMMARY During the March 2, 2026 Council meeting, City staff presented 3 system reliability metrics: the system average interruption duration index (SAIDI), system average interruption frequency index (SAIFI), and customer average interruption duration index (CAIDI)1. In this meeting staff recommended goals for each metric, based upon the performance of adjacent electric utilities and utilities nationwide. While the City Council agreed with staff’s recommendations, they also expressed a desire for quantified reductions based upon Palo Alto’s historical performance in SAIDI, SAIFI, and CAIDI. To address City Council’s comments, and in addition to the goals of outperforming PG&E’s DeAnza District in all reliability metrics and remaining within the top quartile nationally for SAIDI and SAIFI when excluding Major Event Days (MED), staff further recommends setting additional goals of maintaining an Average System Availability Index (ASAI) of 99.99% (four-nines) or better and setting a goal for CAIDI at 10% below the previous three-year average. These two additional goals are intended to ensure that Palo Alto’s system performance remains high regardless of local or national industry trends and alleviates potential concerns with full electrification. 1 Link to March 2, 2026 staff report regarding system reliability: https://cityofpaloalto.primegov.com/viewer/preview?id=0&type=8&uid=822448ca-092b-465b-8859- 00ebddae3a2e Item No.2 Page 2 of 4 BACKGROUND SAIDI (System Average Interruption Duration Index): This measures the average duration of a power outage for the average customer within a given period (usually a year). A lower SAIDI means customers experience less time without power, indicating better overall reliability. SAIFI (System Average Interruption Frequency Index): This measures how often the average customer should expect to experience a power outage over a given period (typically 12-months). A lower SAIFI means customers experience fewer power outages, indicating better service reliability. CAIDI (Customer Average Interruption Duration Index): This measures the average time it takes to restore service to customers who have experienced an outage. A lower CAIDI generally means utilities restore power more quickly when outages do occur, reflecting efficient outage response and quick restoration times. Major Event Days Included Major Event Days Excluded CY SAIDI SAIFI CAIDI SAIDI SAIFI CAIDI 2019 132.8 1.065 124.7 25.3 0.225 112.0 2020 46.2 0.830 55.7 20.9 0.165 126.7 2021 39.7 0.277 143.1 9.4 0.029 329.3 2022 71.7 0.622 115.3 13.4 0.070 190.5 2023 154.1 1.182 130.4 43.5 0.176 247.0 2024 134.7 0.844 159.7 67.4 0.474 142.1 2025 68.1 0.614 110.9 27.2 0.111 245.2 Item No.2 Page 3 of 4 nationally. Measuring the performance of other utilities provides a benchmark for Palo Alto’s performance and the value of the service provided to the community. With MED Without MED SAIDI SAIFI CAIDI SAIDI SAIFI CAIDI 2024 PG&E DeAnza District*471.1 2.020 233.2 211.3 1.580 133.7 2024 Alameda Indices*54.9 0.879 62.5 54.9 0.879 62.5 2024 SVP Indices*208.7 0.981 139.7 161.7 0.850 190.3 EIA Top Quartile 2020-2024 Average*88.3 0.842 87.7 82.9 0.632 73.8 *Numbers for 2025 were not publicly available at the time of this report. Therefore, calendar year 2024 numbers are presented. ANALYSIS Major Event Days Included Major Event Days Excluded CY SAIDI ASAI SAIDI ASAI 2019 132.8 25.3 2020 46.2 20.9 2021 39.7 9.4 2022 71.7 13.4 2023 154.1 43.5 2024 134.7 67.4 2025 68.1 27.2 Item No.2 Page 4 of 4 To address the City’s performance in restoring power following an outage, staff is recommending setting a target for CAIDI of 190 minutes annually when excluding MED. 190 minutes represents the most recent three-year average, less 10%. Adopting this goal will increase focus on restoration of customers following an outage and the preventative replacement of aging equipment. FISCAL/RESOURCE IMPACT STAKEHOLDER ENGAGEMENT ENVIRONMENTAL REVIEW AUTHOR/TITLE: August 5, 2026 Electric System Reliability Update and Goal Setting Utility Advisory Commission PaloAlto.gov Presenter: Terry Crowley, Utilities Chief Operating Officer Background •On March 2, 2026 staff presented electric system reliability metrics to City Council, including proposed reliability goals •Council agreed with staff’s recommended goals, but expressed a desire for goals specifically related to Palo Alto’s past performance that would alleviate concerns with electrification •Staff is seeking input from the UAC on staff’s recommended reliability goals prior to presenting those goals to Council for adoption 2 Primary Reliability Metrics •SAIDI (System Average Interruption Duration Index): Average duration of a power outage for the average customer over the year •SAIFI (System Average Interruption Frequency Index): How often the average customer should expect to experience a power outage over the year •CAIDI (Customer Average Interruption Duration Index): Average time in minutes it takes to restore service to customers who have experienced an outage. 3 Reliability Metrics 4 •Major Event Days (MED) are defined as a day where 10% or more of Palo Alto’s customers are impacted by an outage. •In 2023 the City implemented new software that increased accuracy. Numbers prior to 2023 are potentially understated, but still useful for comparison. Regional and National Reliability Metrics 5 •Calendar year 2025 reliability were not publicly available at the time of this report. With MED Without MED SAIDI SAIFI CAIDI SAIDI SAIFI CAIDI 2024 PG&E DeAnza District 471.1 2.020 233.2 211.3 1.580 133.7 2024 Alameda Indices*54.9 0.879 62.5 54.9 0.879 62.5 2024 SVP Indices*208.7 0.981 139.7 161.7 0.850 190.3 EIA Top Quartile 2020-2024 Average*88.3 0.842 87.7 82.9 0.632 73.8 Staff’s Proposed Reliability Goals •Outperform PG&E’s DeAnza District on all reliability metrics when including and excluding Major Event Days (MED) •Remain within the top quartile nationally for SAIDI and SAIFI when excluding MED •Set a target of an Average System Availability equal to or better than four-nines (99.99% available), equivalent to SAIDI of 52.6 or less. •Set an operational target to lower CAIDI to below 190 to speed restoration times following an outage. 6 Proposed System Availability Goal 7 25.3 20.9 9.4 13.4 43.5 67.4 27.2 52.56 52.56 52.56 52.56 52.56 52.56 52.56 2019 2020 2021 2022 2023 2024 2025 HISTORICAL SAIDI & ASAI TARGETS SAIDI 99.99% Staff’s Proposed Reliability Goals 8 112 126.7 329.3 190.5 247 142.1 245.2 190 190 190 190 190 190 190 HISTORICAL CAIDI & GOAL CAIDI Goal Seeking UAC Recommendation •Outperform PG&E’s DeAnza District on all reliability metrics when including and excluding Major Event Days (MED) •Remain within the top quartile nationally for SAIDI and SAIFI when excluding MED •Set a target of an Average System Availability equal to or better than four-nines (99.99% available), equivalent to SAIDI of 52.6 or less. •Set an operational target to lower CAIDI to below 190 to speed restoration times following an outage. 9 10 Questions/Comments?