Energy Resources Department
Business Objective: Electric


Mission Statement
Provide safe, reliable and efficient electric power to Mesa customers.
Desired Outcomes
  • Electric energy is acquired for and transmitted to Mesa's electric distribution system reliably at the lowest possible costs.
  • Electric energy is distributed safety and reliably to our customers.
  • Our customers' electric energy consumption is accurately and safely measured.
                                                                                                                               Energy Resources Performance Dashboard

Providing Safe, Reliable and Efficient Electric Service for over 100 Years!

The City of Mesa has been offering safe, reliable, and efficient electric utility service for over 100 years. In 1917, the City of Mesa acquired the electric utility that now provides residential and commercial electric utility service to over 17,000 customers within its 5.5 mile radius service area. The City of Mesa Electric Service Area includes the city-center (downtown) and surrounding areas.  

Performance Measures
Electric O&M Cost/Customer
O&M Cost/Customer is a good indicator of whether the costs of our electric staff and operations are growing proportionally in comparison to the growth of the electric system as measured by the change in customers.
Energy Resources uses O&M Cost/Customer as a measure of Performance Improvement by comparing actual O&M Cost/Customer in the current year to the budgeted O&M dollars from the prior year divided by the forecasted customer count (our target values). The data also allows a comparison of how actual O&M Cost/Customer changes from year to year and allows us to measure whether our costs are increasing in proportion to the growth in the number of customers we serve.
Thus, O&M Cost/Customer is a measure of “technical” efficiency where O&M Costs would be the “input” and Customers, when served safely and reliably, would be the measure of output. Efficiency measures how well a business converts inputs such as capital, labor & materials into outputs such as revenue, products and services.

The September 2020 O&M Cost/Customer was $13.63/Customer.
  • 17% below monthly target of $16.49/Customer.
    • September  O&M Costs were $48,260 less than the forecast used to develop the target.
  • 23% more than August's O&M Cost/Customer of 11.04 per customer.
    • O&M costs increased 24% from $187,860 in August to $232,610 in September.
 Actual below target due to underspending in professional services for such things as SRP billings, inspections, tree trimming.

The August 2020 O&M Cost/Customer was $11.04/Customer.
  • 33% below monthly target of $16.49/Customer.
    • August O&M Costs were $93,010 less than the forecast used to develop the target.
  • 5% more than July's O&M Cost/Customer of 10.54 per customer.
    • O&M costs increased 5% from $179,145 in July to $187,860 in August.
 Actual below target due to underspending in materials purchases and professional services for such things as SRP billings, inspections, tree trimming.

The July 2020 O&M Cost/Customer was $10.54/Customer. 
  • 36% below monthly target of $16.49/Customer.
    • July O&M Costs were $101,725 less than the forecast used to develop the target.
  • 38% less than June's O&M Cost/Customer of $16.98 per customer.
    • O&M costs decreased 38% from $289,137 in June to $179,145 in July.
Actuals below target due to underspending in materials purchases, fleet expenditures not posting, and professional services for such things as SRP billings, inspections, tree trimming.

The June 2020 O&M Cost/Customer was $16.98/Customer
  • 5% above monthly target of $16.18/Customer.
    • June O&M Costs were $12,261 more than the forecast used to develop the target.
  • 40% more than May's O&M Cost/Customer of $12.15 per customer.
    •  O&M costs increased 40% from $206,044 in May to $289,137 in June.
Customer count 0.5% or 91 customers below target customer base, which increases actual O&M per customer.  T&D maintenance costs above target budget due to $39,000 in tree trimming invoices.

The May 2020 O&M Cost/Customer was $12.15/Customer.
  • 25% below monthly target of $16.18/Customer.
    • May O&M Costs were $70,832 less than the forecast used to develop the target.
  • 52% less than April's O&M Cost/Customer of $25.08 per customer.
    • O&M costs decreased 51% from $422,005 in April to $206,044 in May.
Substation maintenance costs below target budget due to less SRP Rogers maintenance costs than budgeted. T&D Maintenance costs below target budget due to less tree trimming and steel pole inspection expenditures than budgeted.

The April 2020 O&M Cost/Customer was $25.08/Customer.
  • 18% above monthly target of $21.23/Customer.
    • April O&M Costs were $58,619 more than the forecast used to develop the target.
  • 123% more than March's O&M Cost/Customer of $11.20 per customer .
    • O&M costs increased 120% from $191,808 in March to $422,005 in April.
$75,000 in tree trimming expenses were the major cause of exceeding the monthly target.

The March 2020 O&M Cost/Customer was $11.20/Customer.
  • 31% below monthly target of $16.18/Customer. Customer count 0.1% or 9 customers above target customer base.
    • March O&M Costs were $85,068 less than the forecast used to develop the target.
  • 1% less than February's O&M Cost/Customer of $11.34 per customer.
    • O&M costs decreased 0.08% from $191,962 in February to $191,808 in March.
Substation maintenance costs below target budget due to less SRP Rogers maintenance costs than budgeted. T&D Maintenance costs below target budget due to less tree trimming and steel pole inspection expenditures than budgeted. Three vacancies also are contributing to lower O&M costs.

The February 2020 O&M Cost/Customer was $11.34/Customer.
  • 30% below monthly target of $16.18/Customer. Customer count 1.1% or 183 customers below target customer base.
    • February O&M Costs were $84,914 less than the forecast used to develop the target.
  • 15% less than January's O&M Cost/Customer of $13.41 per customer.
    • O&M costs decreased 15% from $225,659 in January to $191,962 in February.
Substation maintenance costs below target budget due to less SRP Rogers maintenance costs than budgeted. T&D Maintenance costs below target budget due to less tree trimming and steel pole inspection expenditures than budgeted. Three vacancies also are contributing to lower O&M costs.

The January 2020 O&M Cost/Customer was $13.41/Customer.
  • 17% below monthly target of $16.18/Customer.Customer count 1.7% or 293 customers below target customer base. 
    • January O&M Costs were $51,217 less than the forecast used to develop the target.
  • 11% more than December's O&M Cost/Customer of $12.06 per customer.
    • O&M costs increased 10% from $203,439 in December to $225,659 in January.
Substation maintenance costs below target budget due to less SRP Rogers maintenance costs than budgeted. T&D Maintenance costs below target budget due to less tree trimming and steel pole inspection expenditures than budgeted. Three vacancies also are contributing to lower O&M costs.

The December 2019 O&M Cost/Customer was $12.06/Customer.
  • 25% below monthly target of $16.18/Customer. Customer count 1.5% or 255 customers below target customer base. 
    • December O&M Costs were $73,437 less than the forecast used to develop the target.
  • 13% less than November's O&M Cost/Customer of $13.88 per customer.
    • O&M costs decreased 13% from $233,993 in November to $203,439 in December.
Substation maintenance costs below target budget due to less SRP Rogers maintenance costs than budgeted. T&D Maintenance costs below target budget due to less tree trimming and steel pole inspection expenditures than budgeted. Three vacancies also are contributing to lower O&M costs.

The November 2019 O&M Cost/Customer was $13.88/Customer
  • 14% below the monthly target of $16.18/Customer. Customer count 1.5% or 253 customers below target customer base. 
    • November O&M Costs were $42,883 less than the forecast used to develop the target.
  • 31% less than October's O&M Cost/Customer of $20.05 per customer.
    • O&M costs decreased 31% from $339,886 in October to $233,993 in November.
Substation maintenance costs below target budget due to less SRP Rogers maintenance costs than budgeted. T&D Maintenance costs below target budget due to less tree trimming and steel pole inspection expenditures than budgeted. Three vacancies also are contributing to lower O&M costs.

The October 2019 O&M Cost/Customer was $20.05/Customer.
  • 6% below the monthly target of $21.23/Customer.
    • October O&M Costs were $23,500 less than the forecast used to develop the target.
  • 54% more than September's O&M Cost/Customer of $12.98 per customer.
    • O&M costs increased 55% from $218,839 in September to $339,886 in October.
Substation maintenance costs below target budget due to less SRP Rogers maintenance costs than budgeted. Three vacancies also contributed to lower O&M costs.

The September 2019 O&M Cost/Customer was $12.98/Customer.
  • 20% below the monthly target of $16.18/Customer.
    • September O&M Costs were $58,037 less than the forecast used to develop the target.
  • 20% less than August’s O&M Cost/Customer of $16.31 per customer. 
    • O&M Costs decreased 20% from $274,852 in August to $218,839 in September.
Labor and benefits related expenses represented 69% of September's total O&M charges, with materials and supplies from outside vendors representing another 14% of the total. There were no invoices paid in September for outside services, specifically Rogers O&M and Tree Trimming; however, maintaining two (2) vacancies was also a factor in holding down the monthly O&M cost in September.

The August 2019 O&M Cost/Customer was $16.31/Customer.
  • 0.8% above monthly target of $16.18/Customer.
    • August O&M Costs were $2,024 less than the forecast used to develop the target.
    • August customer count was 265 less than the forecast used to develop the target.
  • 55% more than July’s O&M Cost/Customer of $10.52 per customer. 
    • O&M Costs increased 55% from $177,241 in July to $274,852 in August.
Expenditures for salaries and benefits total $196,557, 72% of total O&M expenditures. The labor and benefits expenditures were higher in response to staff spending time performing O&M related work addressing the transmission switch vandalism problem, performing vault inspections, managing outages and other non-CIP work activities. There were $25,251 in expenses for materials and supplies from outside vendors and an invoice for Rogers Substation O&M from SRP in the amount of $5,366.
Customer count was generally unchanged, experiencing a 2-customer decrease from July to August.

The July 2019 O&M Cost/Customer was $10.52/Customer.
  •  35% below monthly target of $16.18/Customer.
    • July O&M Costs were $99,635 less than the forecast used to develop the target.
  • 29% less than June's O&M Cost/Customer of $14.87 per customer.
    • O&M Costs decreased 30% from $253,017 in June to $177,241 in July.
Expenditures for labor were lower in part due to a vacancy and the leave and pay status of some employees. There were $3,608 in expenses for materials and supplies from outside vendors, an invoice for Rogers Substation O&M from SRP in the amount of $2,694 and an invoice for spot tree trimming from West Coast Arborist in the amount of $6,600, 7% of July’s O&M expenditures.

Electric Reliability Outage Duration (SAIDI)

The September 2020 Reliability Duration Index: Target = 1.15 minutes
  • Actual SAIDI was 0.08 minutes of interruptions per customer.
    • 93% below the monthly target of 1.15.
  • 2 non-major event outages affected 22 customers.
    • Average customers affected per outage were 11.
Causes for the two (2) outages were attributed to Blown transformer fuses.
  • 9-6-20 – 1056 N. Wedgewood Circuit 224, 15 customers for 75 minutes BLOWN FUSE CONNECTIONS
  • 9-28-20 – 763 E. 7th Place Circuit 224, 7 customers for 31 minutes BLOWN FUSE UNKNOWN
There was also one (1) Major Event during the month of September. Contractors working on the Robson East rebuild project, inadvertently cut into an energized cable causing a circuit outage. The crew indicated they placed the cutter on the cable to hang it while performing another task and the trigger was engaged when the button contacted the cable below actuating the cut. No one was injured and that employee was removed from the property.  The September SAIDI including major events was 1.37 minutes:
  • 9-9-20 - (MAJOR EVENT) Macdonald and 3rd Place
    • 570 customers for 27 minutes
    • 21 customers for 314 minutes

The August 2020 Reliability Duration Index: Target = 1.05 minutes
  • Actual SAIDI was 0.67 minutes of interruptions per customer.
    • 37% below the monthly target of 1.06.
  • 9 non-major event outages affected 131 customers.
    • Average customers affected per outage were 15.
Causes for the nine (9) outages were attributed to trees = 55% and birds and wildlife = 44%.
  • 8-1-20 – 454 W. 6th Drive Circuit 242, 11 customers for 49 minutes BIRD
  • 8-3-20 – 721 W. Pepper Place Circuit 183, 5 customers for 21 minutes BIRD
  • 8-9-20 – 650 E. 1st. Street Circuit 234, 27 customers for 86 minutes TREE
  • 8-13-20 – 414 E. 3rd Street Circuit 234, 6 customers for 68 minutes BIRD
  • 8-13-20 – 42 N. Harris Circuit 231, 15 customers for 34 minutes WILDLIFE
  • 8-17-20 – 649 N. Date Circuit 183, 36 customers for 151 minutes TREE
  • 8-17-20 – 650 E. 1st Ave Circuit 231, 18 customers for 55 minutes TREE
  • 8-20-20 – 647 E. 3rd Ave Circuit 231, 8 customers for 70 minutes TREE
  • 8-29-20 – 702 W. Pepper Circuit 231 5 customers for 87 minutes TREE
There was also one (1) Major Event during the month of August. Monsoon weather and high winds caused a customer owned palm frond to contact a primary line causing a multiple circuit outage. The customer agreed to remove the palm tree, which was determined to cause multiple outages over several months. The August SAIDI including the major event was 4.96 minutes:
  • 8-5-20 – (MAJOR EVENT) Circuits 244, 171 and 213 CUSTOMER PALM FROND CIRCUIT OUTAGE
    • 1527 customers for 42 minutes
    • 100 customers for 88 minutes

The July 2020 Reliability Duration Index: Target = 2.97 minutes
  • Actual SAIDI was 0.47 minutes of interruptions per customer.
    •  94% below the monthly target of 3.0.
  • 9 non-major event outages affected 165 customers.
    • Average customers affected per outage were 18.
 Causes for the nine (9) outages were attributed to Blown Transformer Fuses 55%, Birds = 33%, Tree =11%.
  • 7-8-20 - 1050 N. Horne Circuit 234, 98 customers for 62 minutes PALM FROND CIRCUIT OUTAGE (tree   trimmer)   
  • 7-11-20 – 1066 N. Wedgewood Circuit 224, 8 customers for 48 minutes BIRD blown transformer fuse
  • 7-11-20 - 725 E. 1st Place Circuit 234, 9 customers for 28 minutes UNKNOWN blown transformer fuse
  • 7-13-20 – 545 N. Lewis Circuit 194, 5 customers for 27 minutes OVERLOADED TRANSFORMER
  • 7-18-20 – 315 N. Fraser Dr. Circuit 222, 8 customers for 39 minutes OVERLOADED TRANSFORMER
  • 7-28-20 – 428 E. Crescent Circuit 222, 16 customers for 21 minutes OVERLOADED TRANSFORMER
  • 7-29-20 – 434 S. Mesa Dr. Circuit 212, 6 customers for 48 minutes UNKNOWN
  • 7-29-20 -- 452 N. Pima Circuit 194, 10 customers for 14 minutes BIRD transformer fuse
  • 7-31-30 – 466 E. Franklin Circuit 232, 5 customers for 24 minutes BIRD transformer fuse
There was also one (1) Major Event during the month of July. Monsoon weather and high winds caused a customer owned palm frond to contact  a primary line causing a multiple circuit outage. The July SAIDI including the major event was 6.40 minutes:
  • 7-24-20 - (MAJOR EVENT) Circuits 244, 171 & 213 CUSTOMER PALM FROND CIRCUIT OUTAGE
    • 1527 Customers for 42 minute
    • 100 Customers for 88 minutes

The June 2020 Reliability Duration Index: Target = 1.91 minutes
  • Actual SAIDI was 0.79 minutes of interruptions per customer.
    • 53% below the monthly target of 1.91.
  • 5 non-major event outages affected 607 customers.
    • Average customers affected per outage were 121.
Causes for the five (5) outages were attributed to birds = 60% and blown transformer fuses = 40%.
  • 6-1-20 – 747 N. Macdonald Circuit 194, 8 Customers for 10 minutes BIRD
  • 6-4-20 – 119 W. 3rd Place Circuit 163, BIRD (transformer fuse blown arrestor)
    • 550 Customers for 18 minutes
    • 36 customers for 76 minutes
  • 6-13-20 – 28 N. Date Circuit 183, 8 Customers for 63 minutes OVERLOADED TRANSFOMRER
  • 6-23-20 – 437 W. Clark, Circuit 243, 5 Customers for 27 minutes BLOWN TRANSFORMER FUSE (transformer was overloaded and later replaced 7-3-20)
There was also one (1) Major Event during the month of June. Monsoon weather and high winds caused a customer owned palm frond to contact a primary line causing a multiple circuit outage. The June SAIDI including the major event was 15.16 minutes:
  • 6-27-20 (MAJOR EVENT) Circuits 244, 171 and a portion of 213, 1,536 customers for 160 minutes. PALM FROND (later determined) These 3 circuits were tied together due to Robson Substation being out for construction.

The May 2020 Reliability Duration Index: Target = 5.04 minutes
  • Actual SAIDI was 0.17 minutes of interruptions per customer.
    • 97% below the monthly target of 5.04.
  • 3 non-major event outages affected 40 customers.
    • Average customers affected per outage were 13.
Causes for the three (3) outages were attributed to blown fuses.
  • 5-1-20 – 251 N. Horne Circuit 222, 20 Customers for 81 minutes PALM FROND
  • 5-6-20 – 743 S. Belleview Circuit 222, 4 Customers for 16 minutes BLOWN TRANSFORMER FUSE
  • 5-15-20 – 921 S. Pioneer Circuit 232, 16 Customers for 75 minutes BIRD
There was also one (1) Major Event during the month of May. A car hit a primary pole causing a circuit outage. The pole was replaced. The May SAIDI including the major event was 5.59 minutes:
  •  5-7-20 – (MAJOR EVENT) 8th Ave. & Hobson Circuit 232, 275 Customers for 335 minutes CAR HIT POLE

The April 2020 Reliability Duration Index: Target = 1.47 minutes
  • Actual SAIDI was 0.19 minutes of interruptions per customer.
    • 87% below the monthly target of 1.47.
  • 3 outages affected 48 customers.
    • Average customers affected per outage were 16.
Causes for the three (3) outages was attributed to birds.
  • 4-12-20 - 245 N. Fraser Dr. E. Circuit 231, 19 customers for 119 minutes BURNED JUMPER on Switch 10160.
  • 4-14-20 - 710 E. Park Place Circuit 234, 9 customers for 34 minutes BIRD (transformer fuse)
  • 4-24-20 – 55 N. Horne Circuit 222, 20 customers for 34 minutes BIRD
There were no major events during the month of April.

The March 2020 Reliability Duration Index: Target = 2.44 minutes
  • Actual SAIDI was 0.04 minutes of interruptions per customer.
    • 98% below the monthly target of 2.41.
  • 2 non-major event outages affected 6 customers.
    • Average customers affected per outage were 3.
Causes for the two (2) outages were attributed to blown fuses.
  • 3-11-20 - 419 N. Drew Circuit 192, 1 customer for 102 minutes BURNED CONNECTION WEATHER HEAD
  • 3-23-20 - 255 N. Fraser Dr. East Circuit 222, 5 customers BLOWN TRANSFORMER FUSE UNKNOWN CAUSE
There was also one (1) Major Event during the month of March. A pad mount switch failed causing a main breaker circuit outage. The March SAIDI including the major event was 33.85 minutes:
•   3-26-20 – (MAJOR EVENT) Kellwood Substation Main Breaker, 3,072 customers for 187 minutes PAD MOUNT SWITCH FAILURE

The February 2020 Reliability Duration Index: Target = 0.21 minutes
  • Actual SAIDI was 0.18 minutes of interruptions per customer.
    • 15% below the monthly target of 0.21.
  • 2 non-major event outages affected 26 customers.
    • Average customers affected per outage were 13.
Causes for the two (2) outages were attributed to blown fuses.
  • 2-2-20 - 222 W. 8th St. Circuit 184, 16 customers for 115 minutes, BLOWN TRANSFORMER FUSE UNKNOWN
  • 2-22-20 – 645 E. 1st Ave Circuit 231, 10 customers for 120 minutes BLOWN TRANSFORMER FUSE CUSTOMER SIDE ISSUE
There was also one (1) Major Event during the month of February. High winds caused a customer owned palm frond to contact a primary line causing a circuit outage. The February SAIDI including the major event was 2.47 minutes:
  • 2-22-20 – (MAJOR EVENT) 251 N. Drew St. Circuit 244 506 customers for 77 minutes CIRCUIT OUTAGE PALM FROND

The January 2020 Reliability Duration Index: Target = 0.20 minutes
  • Actual SAIDI was 0.15 minutes of interruptions per customer.
    • 25% below the monthly target of 0.20.
  • 1 outage affected 56 customers.
    • Average customers affected per outage were 56.
Cause for the outage was attributed to weather.
  • 1-21-20 - 131 N. Horne Circuit 222, 56 customers for 45 minutes WEATHER RELATED
There were no major events during the month of January.

The December 2019 Reliability Duration Index: Target = 0.47 minutes
  • Actual SAIDI was 0.14 minutes of interruptions per customer.
    • 70% below the monthly target of 0.47.
  • 2 outages affected 77customers.
    • Average customers affected per outage were 39.
 Causes for the two (2) outages were attributed to weather = 50% and wildlife = 50%.
  • 12-19-19 – 6th N. Macdonald Circuit 162, 70 customers for 32 minutes CIRCUIT OUTAGE WEATHER
  • 12-24-19 – 661 E. Pepper Circuit 232, 7 customers for 29 minutes WILDLIFE
There were no major events during the month of December.

The November 2019 Reliability Duration Index: Target = 3.23 minutes
  • Actual SAIDI was 0.24 minutes of interruptions per customer.
    • 92% below the monthly target of 3.23.
  • 3 outages affected 67customers.
    • Average customers affected per outage were 22. 
Causes for the three (3) outages were attributed to blown fuses from weather related events.
  • 11-26-19 – 725 E. 1st Place Circuit 234, 8 customers for 21 minutes WEATHER
  • 11-28-19 – 512 W. 3rd Street Circuit 243, 40 customers for 73 minutes WEATHER
  • 11-29-19 – 451 W. 6th Place Circuit 184, 19 customers for 50 minutes WEATHER 
There were no major events during the month of November.

The October 2019 Reliability Duration Index: Target = 2 minutes
  • Actual SAIDI was 0.44 minutes of interruptions per customer.
    • 78% below the monthly target of 2.0
  • 2 outages affected 60 customers.
    • Average customers affected per outage were 12. 
Causes for the two (2) outages were attributed to electrical failure = 50% and bird= 50%.
  • 10-2-19 – 555 S. Lewis Circuit 211 PRIMARY CABLE FAULT
    • 12 Customers for 172 minutes
    • 21 Customers for 145 minutes
    • 2 Customers for 295 minutes
    • Customer for 722 minutes
  • 10-9-20 – 413 S. Mesa Drive Circuit 214, 7 customers for 139 minutes BLOWN FUSE BIRD
There were no major events during the month of October.

The September 2019 Reliability Duration Index: Target = 1.16 minutes
  • Actual SAIDI was 0.07 minutes of interruptions per customer.
    • 94% below the monthly target of 1.16.
  • 5 non-major event outages affected 60 customers.
    • Average customers affected per outage were 12.
Causes for the five (5) outages were attributed to blown transformer fuses = 60% and birds = 40%.
  • 9-3-19 – 719 E. Kino Dr. Circuit 224, 12 customers for 15 minutes BLOWN FUSE UNKNOWN
  • 9-7-19 - 301 E. 7th Dr. Circuit 222, 5 customers for 28 minutes BLOWN FUSE UNKNOW
  • 9-11-19 – 657 E. Marilyn Circuit 232, 10 customers for 23 minutes BIRD
  • 9-19-19 – 544 W. 6th Drive Circuit 242, 11 customers for 24 minutes BIRD
  • 9-23-19 – 46 W. 8th Place Circuit 194, 22 customers for 18 minutes BLOWN FUSE UNKNOWN
There was also one (1) Major Event during the month of September. High winds caused a tree to fall onto single phase primary, causing 3 phase primary downstream feed pole to the north, to break. Both the single-phase overhead tap and the three-phase riser pole were radially fed and could not be refed from another direction. The downed wire from the broken pole caused three fuses to blow.  The September SAIDI including major events was 13.39 minutes:
  • 9-14-19 – (MAJOR EVENT) 621 E. Millet Circuit 232 TREE WEATHER
    • 50 customers for 142 minutes
    • 150 customers for 742 minutes
 
The August 2019 Reliability Duration Index: Target = 1.06 minutes
  • Actual SAIDI was 0.27 minutes of interruptions per customer.
    • 75% below the monthly target of 1.06.
  • 5 non-major event outages affected 43 customers.
    • Average customers affected per outage were 8.
Causes for the two (2) outages were attributed to blown transformer fuses = 80% and mylar balloon = 20%.
  • 8-2-19 – 755 W. 2nd Street Circuit 183, 4 customers for 55 minutes BLOWN TRANSFORMER FUSE
  • 8-7-19 – 517 W. 3rd Street Circuit 243, 30 customers for 63 minutes BLOWN TRANSFORMER FUSE
  • 8-17-19
    • 427 E. Crescent Circuit 174, 16 customer for 35 minutes BLOWN TRANSFORMER FUSE
    • 747 S. Pima Circuit 214, 18 customers for 59 minutes MYLAR BALLOON
    • 331 N. LeSueur Circuit 234, 14 customers for 58 minutes BLOWN TRANSFORMER FUSE
There were also two (2) Major Events during the month of August. One of the ME outages was transmission related, caused by a vandal breaking the lock and opening a gang operated 69kV transmission switch controlling power flow into Robson and Fraser Substations. It disrupted service for approximately 400 minutes. There was also another ME outage caused by a lightning strike. The August SAIDI including major events was 50.72 minutes:
  • 8-03-19 – (MAJOR EVENT) 114 W. 8th Place Circuit 194, 1 customer for 89 minutes LIGHTNING
  • 8-22-19 - (MAJOR EVENT) 69kV Line VANDALISM
    • 2420 customers for 110 minutes
    • 1835 customers for 111 minutes
    • 2435 customers for 90 minutes
    • 1857 customers for 89 minutes

The July 2019 Reliability Duration Index: Target = 3.0 minutes
  • Actual SAIDI was 0.29 minutes of interruptions per customer.
    •  90% below the monthly target of 3.0.
  • 8 non-major event outages affected 1,235 customers.
    • Average customers affected per outage were 154. 
Causes for the eight (8) outages were attributed to birds = 63%, unknown = 25% and utility human error = 13%.
  • 7-2-19 – 251 N. Horne Circuit 222, 12 customers for 22 minutes BIRD
  • 7-4-19 – 856 S. Coleman Circuit 242, 13 customers for 20 minutes UNKNOWN
  • 7-11-19 – 115 S. Country Club Circuit 183, 1 customer for 81 minutes BIRD
  • 7-14-19 – 657 E. Marilyn Ave Circuit 232, 10 customers for 52 minutes BIRD
  • 7-22-19 – 251 N. Horne Circuit 232, 11 customers for 72 minutes BIRD
  • 7-23-19 – 1506 E. Main St. Circuit 231, 5 customers for 67 minutes UNKNOWN
  • 7-29-19 – 640 N. Mesa Dr. Lewis Substation HUMAN (Control Room Switching) ERROR
  • 7-29-19 – 51 E. 7th Dr. Circuit 214, 14 Customers for 25 minutes BIRD
There were also four (4) Major Events during the month of July including a transmission outage caused by equipment failure/malfunction at Rogers. The transmission outage, which disrupted power to the entire Mesa ESA, was treated as a major event since it was associated with the source power supply from Rogers Substation which is operated and maintained by SRP. The other three outages were caused by monsoon weather conditions. The July SAIDI including major events was 148.11 minutes:
  • 7-27-19 – (MAJOR EVENT) Rogers Substation System Outage EQUIPMENT FAILURE
  • 7-30-19 – (MAJOR EVENT) Circuit 234, 586 Customers for 196 minutes TREE
  • 7-30-19 – (MAJOR EVENT) 216 N. Fraser Dr. Circuit 222, 55 customers for 58 minutes TREE
  • 7-31-19 – (MAJOR EVENT) 765 E. 1st. Place Circuit 234, 30 customers for 107 minutes TREE

Average Residential Electric Bill Compared to SRP
Mesa Average Residential Customer Electric bills are 16.7% less than SRP for the period October 2019 to September 2020.

Electric Reliability Outage Frequency (SAIFI)
 
September 2020 Reliability Frequency Index:
There were two (2) localized outages and one (1) Major Event totaling three (3) outages in September. The two outages disrupted power to 22 customers and resulting in a “total” SAIFI (frequency) index of 0.08 interruption per customer was below the target of 1.15 for the month of September based on non-major events. The average number of customers affected per outage was 11. The (1) Major Event during the month of September was caused by a contractors working on the Robson East rebuild project, inadvertently cut into an energized cable causing a circuit outage. The crew indicated they placed the cutter on the cable to hang it while performing another task and the trigger was engaged when the button contacted the cable below actuating the cut. No one was injured and that employee was removed from the property. The two (2) reportable outages in September were localized outages due to a blown transformer fuses caused by bad connections.

August 2020 Reliability Frequency Index:
There were nine (9) localized outages and one (1) Major Event totaling ten (10) outages in August. The nine outages disrupted power to 131 customers and resulting in a “total” SAIFI (frequency) index of 0.008 interruption per customer was below the target of 0.0019 for the month of August based on non-major events. The average number of customers affected per outage was 15. The (1) Major Event during the month of August was caused by a customer owned palm tree. The nine (9) reportable outages in July were localized outages due to a blown transformer fuses caused by trees, birds and other wildlife.

July 2020 Reliability Frequency Index:
There were nine (9) localized outages and one (1) Major Event totaling ten (10) outages in July. The nine outages disrupted power to 165 customers and resulting in a “total” SAIFI (frequency) index of 0.009 interruption per customer was below the target of 0.087 for the month of July based on non-major events. The average number of customers affected per outage was 18.3. The (1) Major Event during the month of July was caused by a customer owned palm tree. The nine (9) reportable outages in July were localized outages due to a blown transformer fuses caused by wildlife, overloaded transformers and a palm frond from tree trimmer.

June 2020 Reliability Frequency Index:
There were five (5) localized outages and one (1) Major Event totaling six (6) outages in June. The five outages disrupted power to 607 customers and resulting in a “total” SAIFI (frequency) index of 0.359 interruption per customer exceeding the target of 0.015 for the month of June based on non-major events. The average number of customers affected per outage was 121.4. The (1) Major Event during the month of June was caused by a customer owned palm tree. The five (5) reportable outages in June were localized outages due to a blown transformer fuses caused by wildlife and an overloaded transformer.

May 2020 Reliability Frequency Index:
There were three (3) localized outages and one (1) Major Event totaling four (4) in May. The three outages disrupted power to 40 customers and resulting in a “total” SAIFI (frequency) index of 0.002 interruption per customer based on non-major events. The average number of customers affected per outage was 13.3. The one (1) Major Event during the month of May was caused by a CAR HIT POLE accident. The “reportable” SAIFI Index in May was 0.002 interruptions per customer which was below the monthly SAIFI target of 0.04 interruptions per customer. The three (3) reportable outages in May were localized outages due to a blown transformer fuse caused by wildlife and palm fronds.

April 2020 Reliability Frequency Index:
There were three (3) outages in April, disrupting power to 48 customers and resulting in a “total” SAIFI (frequency) index of 0.003 interruption per customer based on all outages, major and non-major events. The average number of customers affected per outage was 16. There were no qualifying Major Events during the month of April. The “reportable” SAIFI Index in April was 0.003 interruptions per customer which was below the monthly SAIFI target of 0.007 interruptions per customer. The three (3) reportable outages in April were localized outages due to a blown transformer fuse caused by wildlife and a burned jumper on Switch 10160.

March 2020 Reliability Frequency Index:
There were two (2) localized outages and one (1) multiple circuit outage during the month of March, disrupting power to 1026 customers and resulting in a “total” SAIFI (frequency) index of 0.183 interruption per customer based on  events. The average number of customers affected per outage were 1026. The “reportable” SAIFI Index in March was 0.183 interruptions per customer which was above the monthly SAIFI target of 0.029 interruptions per customer. The two (2) outages in March were localized outages due to a blown transformer fuse and a burned connection at weather head. The one (1) Circuit outage was caused by a pad mount switch failure that caused a multiple circuit outage.

February 2020 Reliability Frequency Index:
There were two (2) localized outages and one (1) Major Event totaling three (3) outages during the month of February. The two reportable outages created 3,040 minutes of interruption resulting in a total SAIFI index of 0.0015, which is below the monthly SAIFI target of 0.003 minutes of interruptions per customer. 26 total customers were affected during the month of February and the average customer affected per outage were 13. The two (2) outages in February were localized outages due to blown transformer fuses. The one (1) Major Event was a circuit outage caused by a customer owned palm frond.

January 2020 Reliability Frequency Index:
There was 1 outage in January, disrupting power to 56 customers and resulting in a “total” SAIFI (frequency) index of 0.00332 interruption per customer based on all outages, major and non-major events. The average number of customers affected per outage was 56. There were no qualifying Major Events during the month of January. The “reportable” SAIFI Index in January, was 0.00332 interruptions per customer which was well below the monthly SAIFI target of 0.004 interruptions per customer. There were no major events during the month of January. The outage in January was a localized outage due to 2 blown transformer fuses caused by a palm frond on Circuit 222 believed to be caused by weather.

December 2019 Reliability Frequency Index:
There were 2 outages in December, disrupting power to 77 customers and resulting in a “total” SAIFI (frequency) index of 0.00457 interruption per customer based on all outages, major and non-major events. The average number of customers affected per outage was 38.5. There was no qualifying Major Events during the month of November. The “reportable” SAIFI Index in December, was 0.00457 interruptions per customer which was well below the monthly SAIFI target of 0.009 interruptions per customer. There were no major events during the month of December. The 2 outages in December were localized outages due to a blown transformer fuse caused by wildlife and a lockout on Circuit 162 believed to be caused by weather.

November 2019 Reliability Frequency Index:
There were 3 outages in November, disrupting power to 67 customers and resulting in a “total” SAIFI (frequency) index of 0.00398 interruption per customer based on all outages, major and non-major events. The average number of customers affected per outage was 22.3. There was no qualifying Major Events during the month of November. The “reportable” SAIFI Index in November, was 0.00398 interruptions per customer which was well below the monthly SAIFI target of 0.02 interruptions per customer. These 3 outages were localized outages resulting from blown fuses which were all weather related.

October 2019 Reliability Frequency Index:
There were 2 outages in October, disrupting power to 43 customers and resulting in a “total” SAIFI (frequency) index of 0.00255 interruption per customer based on all outages, major and non-major events. The average number of customers affected per outage was 8.6. The “reportable” SAIFI Index in October, was 0.00255 interruptions per customer which was well below the monthly SAIFI target of 0.005 interruptions per customer. The 2 localized outages data is as follows: One resulted from a 1/0 primary cable fault and one was the result of 2 blown fuses on a 120/240 open delta transformer bank which a bird is believed to have caused.

September 2019 Reliability Frequency Index:
There were 6 outages in September, disrupting power to 260 customers and resulting in a “total” SAIFI (frequency) index of 0.01544 interruption per customer, based on all outages, major and non-major events. The “reportable” SAIFI Index in September, which is based on non-ME’s and excludes major events, was 0.003562 interruptions per customer which was well below the monthly SAIFI target of 0.010 interruptions per customer.
There was one (1) major event (ME) outage and five (5) non-ME outages. The ME outage resulted in a SAIFI of 0.01188 interruption per customer, affecting 200 customers, 77% of those experiencing and outage in September. High winds caused a tree to fall onto single phase primary, causing 3 phase primary downstream feed pole to the north, to break. Both the single-phase overhead tap and the three-phase riser pole were radially fed and could not be refed from another direction. The downed wire from the broken pole caused three fuses to blow. The five (5) non-ME outages were local, and affected 60 customers. Birds in contact with energized equipment was identified as the cause of 2 of the non-ME outages, while there were no causes identified for the remaining 3, which all had blown fuses.

August 2019 Reliability Frequency Index:
There were 7 outages in August, resulting in a SAIFI index for all events of 0.512292 interruption per customer. The reported August SAIFI, which excludes major events (ME’s), was 0.512233 interruptions per customer, was the result of six (6) non-ME outages and was more than 2500% above the August target of 0.019 interruptions per customer. There was one (1) ME outage in August with a SAIFI of 0.000059 interruptions per customer. Most of the August SAIFI index, was associated with transmission outage caused by a vandal breaking the lock and opening a gang operated 69kV transmission switch controlling power flow into Robson and Fraser. The SAIFI associated with the vandalism incident was 0.50736 interruptions per customer, which is approximately 99% of the August SAIFI and affected 8,544 customers. There was 1 ME caused by a lightning strike, with a SAIFI of 0.000059 interruptions per customer. This single event affected on 1 customer. The other 5 non-ME local outages included a mylar balloon incident and 4 events involving blown fuses of unknown causes. The cumulative SAIFI for the other 5 non-ME outages was 0.00487 interruptions per customer; these outages disrupted service to 82 customers.

July 2019 Reliability Frequency Index:
There were 12 outages in July, 4 were major event outages while 8 were non major event outages. The outages included a transmission outage caused by equipment failure/malfunction at Rogers Substation, and 2 circuit outages.  The transmission outage, which disrupted power to the entire Mesa ESA of 16,840 customer, was treated as a major event since it was associated with the source power supply from Rogers Substation which is operated and maintained by SRP,  as were 1 of the circuit outages and 2 of the local outages on the July 30 and 31. The later three outages were caused by monsoon weather conditions. 
The 12 outages affect 18691 customers and resulted in a SAIFI index of 1.11 interruptions per customer. The 4 major event outages affected 17456 and had a SAIFI index of 1.04 interruptions per customer.
In comparison, the non-major event outages affected 1235 customers and resulted in a SAIFI index of 0.07 interruptions per customer. The July SAIFI was 90% below the monthly target of 0.088 minutes of interruptions per customer. The causes of non-major event outages in July included birds in contact with energized equipment, a switching error (causing a circuit outage) and unknown causes.


Lost-Time Accidents - Electric
The City of Mesa Electric Utility has gone over 793 days without a lost-time accident (since 08/13/2018). The following is a summary of the current fiscal year results for this metric:
July 2019 through June 2020:
In accordance with our department's values to work safely, there have been no lost-time accidents from July 2019 through June of 2020 in the City of Mesa Electric Utility. Employees continue to communicate and use safe working practices as part of the daily activities, safety topics are covered in the weekly tailgate sessions, as well as the monthly department meetings.