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 safely 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 2021 O&M Cost/Customer was $16.33/Customer
  • 27% below monthly target of $22.24/Customer.
    • September O&M Costs were $96,652 less than the forecast used to develop the target.
  • 35% more than August's O&M Cost/Customer of $12.13 per customer.
    • O&M costs increased 35% from $12.13 in August to $16.33 in September.
  • Actuals are below target due to Inspections during the month of September were less than projected, SRP billings came in lower than forcasted, tree trimming invoices posted in October due to cycle schedule.

The August 2021 O&M Cost/Customer was $12.13/Customer
  • 28% below monthly target of $16.80/Customer.
    • August O&M Costs were $76,447 less than the forecast used to develop the target.
  • 24% more than July's O&M Cost/Customer of $9.85 per customer.
    • O&M costs increased 22% from $169,773 in July to $209,808 in August. 
Actuals are below target due to underspending in SRP billings, tree trimming, and inspections during the month of August were less than projected. 

The July 2021 O&M Cost/Customer was $9.85/Customer.
  • 41% below monthly target of $16.80/Customer.
    • July's O&M Costs were $116,482 less than the forecast used to develop the target.
  • 41% less than June's O&M Cost/Customer of $14.65 per customer.
    • O&M costs decreased 33% from $253,481 in June to $169,773 in July. 
Actuals are below target due to underspending in material purchases and professional services for items such as SRP billings, inspections and tree trimming. 

The June 2021 O&M Cost/Customer was $16.76/Customer.
  • 2% above monthly target of $16.49/Customer.
    • June's O&M Costs were $10,483 more than the forecast used to develop the target.
  • 58% more than Mays' O&M Cost/Customer of $10.66 per customer.
    • O&M costs increased 57% from $184,496 in May to $291,353 in June. 
Overspent the target due to fleet charges from year end reconciliation and posting one period late from FY end.  

The May 2021 O&M Cost/Customer was $10.66/Customer.
  • 35% below monthly target of $16.49/Customer.
    • May's O&M Costs were $96,374 less than the forecast used to develop the target.
  • 26% less than April's O&M Cost/Customer of $14.47 per customer.
    • O&M costs decreased 26% from $250,350 in April to $184,496 in May.
Underspent the target due to a capital focused workload for the month and professional services were down for SRP billing and tree trimming. Minimal inspections throughout May and vacancies made a slight impact.

The April 2021 O&M Cost/Customer was $14.47/Customer.
  • 33% below monthly target of $21.75/Customer.
    • April O&M costs were $120,092 less than the forecast used to develop the target.
  • 38% more than March's O&M Cost/Customer of $10.39 per customer. The target and actual are higher in April because there are three pay periods in the month.
    • O&M costs increased 39% from $181,498 in March to $250,350 in April.
Actual below target due to underspending in professional services for such things as SRP billings, inspections, and focus on capital work.

The March 2021 O&M Cost/Customer was $10.39/Customer.
  • 37% below monthly target of $16.49/Customer.
    • March's O&M costs were $99,372 less than the forecast used to develop the target.
  • 11% less than February's O&M Cost/Customer of $11.67 per customer.
    • O&M costs decreased 19% from $200,864 in February to $181,498 in March.
SRP billings for O&M at Rogers and tree trimming invoices were lower than budgeted. Heavy capital work focused month along with a couple of vacancies contributed to actuals coming in below target.

The February 2021 O&M Cost/Customer was $11.67/Customer.
  • 29% below monthly target of $16.49/Customer.
    • February's O&M costs were $80,006 less than the forecast used to develop the target.
  • 19% less than January's O&M Cost/Customer of $14.39 per customer.
    • O&M costs decreased 19% from $246,613 in January to $200,864 in February.
O&M cost per customer was below target due to a capital focused workload for the month. Staff vacancies also contributed and lower than projected SRP Rogers O&M costs were a factor.

The January 2021 O&M Cost/Customer was $14.39/Customer.
  • 13% below monthly target of $16.49/Customer.
    • January's O&M costs were $34,257 less than the forecast used to develop the target.
  • 36% more than December's O&M Cost/Customer of $10.55 per customer.
    • O&M costs increased 37% from $180,616 in December to $246,613 in January.
January’s cost per customer was below target for the month due to less tree trimming removals and steel pole inspection expenditures than budgeted. Two vacancies also are contributing to lower O&M costs.

The December 2020 O&M Cost/Customer was $10.55/Customer.
  • 36% below monthly target of $16.49/Customer.
    • December's O&M costs were $100,254 less than the forecast used to develop the target.
  • 13% less than November's O&M Cost/Customer of $12.15 per customer.
    • O&M costs decreased 13% from $208,125 in November to $180,616 in December.
SRP billings for O&M at Rogers and tree trimming invoices were lower than budgeted. Heavy capital work focused month along with a couple of vacancies contributed to actuals coming in below target.

The November 2020 O&M Cost/Customer was $12.15/Customer.
  • 26% below monthly target of $16.49/Customer.
    • November O&M costs were $72,741 less than the forecast used to develop the target.
  • 19% less than October's O&M Cost/Customer of $15.09 per customer.
    • O&M costs decreased 19% from  $258,170 in October to $208,129 in November.
O&M cost per customer was below target due to a capital focused workload for the month. Staff vacancies also contributed and lower than projected tree trimming invoices and SRP Rogers O&M costs were a factor.

The October 2020 O&M Cost/Customer was $15.09/Customer.
  • 31% below monthly target of $21.75/Customer.
    • October O&M costs were $112,272 less than the forecast used to develop the target.
  • 10% more than September's O&M Cost/Customer of $13.63 per customer.
    • O&M costs increased 10% from  $232,610 in September to $258,170 in October.
October’s cost per customer was below target for the month due to tree trimming invoices and steel pole inspection expenditures were less than budgeted. Two vacancies also are contributing to lower O&M costs.

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.
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. Two vacancies also are contributing to lower O&M costs.

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% 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.



Electric Reliability -  Outage Duration (SAIDI)

The September 2021 Reliability Duration Index: Target = 0.125 minutes
Actual SAIDI was 0.125 minutes of interruptions per customer.
• 89% below the monthly target of 1.14.
• 4 non-major events that caused 4 outages.
• Average customers affected per outage were 8.

Causes for the four (4) outages were attributed to Equipment Failure=25%, No Cause=75%.
• 9-6-21 – 341 S. Lesueur Circuit 231, 11 customers for 42 minutes BLOWN TRANSFORMER FUSE
• 9-10-21 – 1012 N. April Circuit 224, 4 customers for 21 minutes BLOWN TRANSFORMER FUSE
• 9-11-21 – 1140 N Dresden Circuit 224, 9 customers for 120 minutes TRANSFORMER FUSE-REPLACED TRANSFORMER
• 9-11-21 – 556 E. Franklin Ave. Circuit 232, 8 customers for 68 minutes BLOWN TRANSFORMER FUSE

There was also two (2) Major Events during the month of September that caused four (4) separate outages. Monsoon weather, high winds and lightning caused damage to overhead equipment and trees. The September SAIDI including major events was 5.342 minutes:
• 9-18-21 –Monsoon STORM (MAJOR EVENT) • 125 N. Fraser Dr. East Circuit 231, 8 customers for 17 minutes BLOWN LINE FUSE
• Lewis West Circuit 194, 735 customers for 79 minutes MAJOR EVENT-WIND/TREES
• 463 W. 3rd Place Circuit 243, 31 customers for 111 MAJOR EVENT-BLOWN LINE FUSE
• 9-22-21 – Robson West Circuit 212, 521 customers for 55 minutes MICROBURST (MAJOR EVENT) EZUP

The August 2021 Reliability Duration Index: Target = 1.04 minutes
• Actual SAIDI was 0.123 minutes of interruptions per customer.
• 78% below the monthly target of 1.04.
• 5 non-major events that caused 5 outages.
• Average customers affected per outage were 6.6.

Causes for the five (5) outages were attributed to Wildlife (BIRD)=56%, Equipment Failure=22%, Overloads=22%.
•   8-2-21 – 456 S. Lesueur Circuit 174, 7 customers for 60 minutes TRANSFORMER FUSE-BIRD
•   8-3-21 – 510 N. Horne Circuit 223, 9 customers for 53 minutes TRANSFORMER FUSE-BIRD
•   8-21-21 – 554 W. Clark Circuit 243, 3 customers for 39 minutes TRANSFORMER FUSE-BIRD
•   8-27-21 – 34 N. Harris Circuit 231, 12 customers for 46 minutes BLOWN TRANSFORMER FUSE
•   8-28-21 – 52 S. Beverly Circuit 181, 2 customers for 283 minutes TRANSFORMER REPLACEMENT (BUSHING)

There was also three (3) Major Events during the month of August that caused nine (9) separate outages. Monsoon weather, high winds and lightning caused damage to overhead equipment and trees. The August SAIDI including major events was 9.948 minutes:
•   8-16-21 –Monsoon STORM (MAJOR EVENT)
• Circuit 232, 926 customers for 118 minutes LOCKOUT PALM FRONDS
• 509 S. Hobson Circuit 232, 5 customers for 75 minutes PALM FRONDS
• 705 N. Date Circuit 184, 75 customers for 248 minutes PINE TREE
•   8-17-21 – 64 S. Ashland Circuit 231, 66 customers for 32 minutes Monsoon STORM (MAJOR EVENT)
•   8-18-21 – Kellwood South Substation Circuit 243 Monsoon STORM (MAJOR EVENT) TREE IN PRIMARY
• Circuit 243, 1 customer for 361 minutes
• Circuit 243, 1 customer for 295 minutes
• Circuit 243, 41 customers for 149 minutes
• Circuit 243, 556 customers for 56 minutes
• Circuit 243, 7 customers for 257 minutes

The July 2021 Reliability Duration Index: Target = 2.94 minutes
• Actual SAIDI was 0.64 minutes of interruptions per customer.
• 78% below the monthly target of 2.94.
• 7 non-major events that caused 9 outages.
• Average customers affected per outage were 14.

Causes for the seven (7) events that included nine (9) outages were attributed to Wildlife (BIRD)=56%, Equipment Failure=22%, Overloads=22%.
•   7-4-21 - 414 S. Lebaron Circuit 214 BIRD
• 10 customers for 55 minutes
• 2 customers for 161 minutes
•   7-5-21 – 221 S. Sirrine Circuit 212, 8 customers for 45 minutes BLOWN FUSE (overload)
•   7-14-21 – 251 N. Horne Circuit 222 BIRD-RISER SWITCH REPAIR
• 55 customer for 111 minutes
• 29 customers for 78 minutes
•   7-17-21 – 660 E. Broadway Rd. Circuit 231, 1 customer for 50 minutes BIRD
•   7-26-21 – 623 S. County Club Circuit 171, 6 customers for 14 minutes BLOWN FUSE (overload)
•   7-28-21 – 756 S. Morris Circuit 171, 14 customers for 63 minutes BLOWN FUSE (overload)
•   7-29-21 – 725 N. Grand Circuit 194, 5 customers for 81 minutes BLOWN FUSE (overload)
There was also one (1) Major Event during the month of July that caused two (2) separate outages. Monsoon weather, high winds and lightning most likely caused damage to overhead equipment. The July SAIDI including major events was 0.86 minutes:
•   7-23-21 – Monsoon STORM (MAJOR EVENT)
• 733 W. Main 6 customers for 440 minutes
• 150 W. 9th St. 13 customers for 95 minutes

The June 2021 Reliability Duration Index: Target = 1.89 minutes
• Actual SAIDI was 7.038 minutes of interruptions per customer.
• 272% above the monthly target of 1.89.
• 12 non-major events that caused 16 outages and four (4) Major Events during June.
• Average customers affected per outage were 186.

Causes for the twelve (12) events that included sixteen (16) outages were attributed to Equipment Failure=50%, Wildlife=13%, Overloads=13% Unknown=13%
•   6-2-21 – Lewis Substation, Temperature gauge on transformer monitor battery failure
• Circuit 191- 650 Customers for 43 minutes
• Circuit 192- 902 Customers for 44 minutes
• Circuit 193- 18 Customers for 37 minutes
• Circuit 194- 734 Customers for 44 minutes
•   6-6-21 – 501 N. Ashland Circuit 223, 11 customers for 42 minutes BIRD
•   6-8-21 – 319 N. Mesa Dr Circuit 234, 13 customers for 26 minutes BIRD
•   6-11-21 – 715 E. Brown Circuit 224, 13 customers for 45 minutes BLOWN FUSE (overload)
•   6-12-21 – 726 W. 2nd Ave Circuit 243, 6 customers for 79 minutes BLOWN FUSE (overload)
•   6-16-21 – 710 W. 1st Street Circuit 183, TRANSFORMER WING POT IFD
• 14 customers for 85 minutes
• 14 customers for 177 minutes
•   6-17-21 – 526 W. 1st Ave Circuit 183, 88 customers for 74 minutes UNKNOWN (stinger burned)
•   6-17-21 – 514 N. Cherry Circuit 184, 10 customers for 26 minutes BLOWN FUSE (overload)
•   6-19-21 – 508 E. 9th Ave Circuit 232, 4 customers for 30 minutes BLOWN FUSE
•   6-19-21 – 614 W. 2nd Ave Circuit 183, 14 customers for 35 minutes BLOWN FUSE
•   6-20-21 – 657 E. 7th Place Circuit 224, 12 customers for 30 minutes BLOWN FUSE (overload)
•   6-29-21 – Robson Substation Circuit 212, 465 customers for 16 minutes NON-RECLOSE (unknown)

The May 2021 Reliability Duration Index: Target = 4.99 minutes
  • Actual SAIDI was 0.016 minutes of interruptions per customer.
    • 99% below the monthly target of 4.99.
  • 1 non-major event outages affected 15 customers.
    • Average customers affected per outage were 15.
Cause for the (1) outages was attributed to Blown transformer fuse, due to age.
  • 5-27-21 431 E. Crescent , Circuit 174, 15 customers for 19 minutes BLOWN TRANSFOMER FUSE AGE
There were no major events during the month of May.

The April 2021 Reliability Duration Index: Target = 1.45 minutes
  • Actual SAIDI was 0.21 minutes of interruptions per customer.
    • 86% below the monthly target of 1.45.
  • 4 non-major event outages affected 33 customers.
    • Average customers affected per outage were 8.25.
Cause for the (4) outages was attributed to Blown line fuse, transformer fuse and a transformer failure due to age.
  • 4-8-21 115 S. Country Club, Circuit 244, 2 customers for 25 minutes BLOWN TRANSFOMER FUSE FROM BIRD
  • 4-17-21 414 S. Lebaron, Circuit 214, 5 customers for 84 minutes BLOWN LINE FUSE AGE
  • 4-30-21 546 S. Country Club, Circuit 213, 14 customers for 198 minutes TRANSFORMER FAILURE AGE
  • 4-30-21 546 S. Country Club, Circuit 213, 12 customers for 30 minutes TRANSFORMER FAILURE AGE
There were no major events during the month of April.

The March 2021 Reliability Duration Index: Target = 2.42 minutes
  • Actual SAIDI was 0.037 minutes of interruptions per customer.
    • 98% below the monthly target of 0.21.
  • 2 non-major event outages affected 9 customers.
    • Average customers affected per outage were 4.5.
Cause for the (2) outages were attributed to weather blowing palm fronds into secondaries and a blown transformer fuse.
  • 3-3-2021 654 W. 1st Street, Circuit 243 - 2 customers for 150 minutes
  • 3-26-2021 61 N. Miller Street, Circuit 232 - 7 customers for 50 minutes
No Major Events for the month of March.

The February 2021 Reliability Duration Index: Target = 0.208 minutes
  • Actual SAIDI was 0.14 minutes of interruptions per customer.
    • 33% below the monthly target of 0.21.
  • 2 non-major event outages affected 41 customers.
    • Average customers affected per outage were 20.5.
Cause for the (2) outages were attributed to human error tree trimming contractor
  • 2-10-2021 709 East Park Place, Circuit 232 - 28 customers for 49 minutes
  • 2-10-2021 709 East Park Place, Circuit 232 - 13 customers for 80 minutes
No Major Events for the month of February.

The January 2021 Reliability Duration Index: Target = 0.20 minutes
  • Actual SAIDI was 0.10 minutes of interruptions per customer.
    • 50% below the monthly target of 0.20.
  • 1 non-major event outages affected 21 customers.
    • Average customers affected per outage were 21.
Cause for the (1) outage was attributed to Blown line fuse from TREE
  • 1-06-20 – 729 N. Date  Circuit 1844, 21 customers for 59 minutes Failed Termination.
No Major Events for the month of January.

The December 2020 Reliability Duration Index: Target = 0.47 minutes
  • Actual SAIDI was 0.00 minutes of interruptions per customer. There were no outages during the month of December.

The November 2020 Reliability Duration Index: Target = 3.20 minutes
  • Actual SAIDI was 0.19 minutes of interruptions per customer.
    • 94% below the monthly target of 3.20.
  • 1 non-major event outages affected 45 customers.
    • Average customers affected per outage were 45.
Cause for the (1) outage was attributed to Blown line fuse from TREE
  • 11-20-20 – 466 E. Royal Palms Circuit 224, 45 customers for 70 minutes BLOWN FUSE TREE BRANCH
There was also one (1) Major Event during the month of November. A mylar balloon was found in the primary overhead line causing a SF6 sectionalizing switch to open, which prevented a circuit outage. The October SAIDI including major events was 1.29 minutes:

  • 11-24-20 - (MAJOR EVENT) 562 S. Hobson
  • 57 customers for 37 minutes MYLAR BALLOON

The October 2020 Reliability Duration Index: Target = 0.99 minutes
  • Actual SAIDI was 0.04 minutes of interruptions per customer.
    • 96% below the monthly target of 0.99.
  • 3 non-major event outages affected 30 customers.
    • Average customers affected per outage were 10.
Causes for the three (3) outages were attributed to Blown transformer fuses from BIRDS
  • 10-15-20 – 522 W. Pepper Place Circuit 243, 10 customers for 31 minutes BLOWN FUSE BIRDS
  • 10-20-20 – 522 W. Pepper Place Circuit 243, 10 customers for 29 minutes BLOWN FUSE BIRDS
  • 10-21-20 – 504 W. Pepper Place Circuit 243, 10 customers for 14 minutes BLOWN FUSE BIRDS
Outreach was done and it was discovered that a neighbor was feeding the birds in the area. We discussed the results and customer agreed to refrain from future feeding.
There was also one (1) Major Event during the month of October. A mylar balloon was found in the primary overhead line causing a SF6 sectionalizing switch to open, which prevented a circuit outage. The October SAIDI including major events was 1.29 minutes:
  • 10-10-20 - (MAJOR EVENT) 455 E. 8th Ave
  • 352 customers for 60 minutes MYLAR BALLOON

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

Average Residential Electric Bill Compared to SRP
Mesa Average Residential Customer Electric bills are 4.8% less than SRP for the period October 2020 to September 2021.

Electric Reliability Outage Frequency (SAIFI)

September 2021 Reliability Frequency Index:
There were four (4) localized events causing 4 outages during the month of September. These reportable outages disrupted power to 32 customers and resulted in a “total” SAIFI (frequency) index of 0.002 interruption per customer and was below the target of 0.010 for the month of September based on non-major events. These outages were due to blown fuses and equipment failures. The average number of customers affected per outage was 8. There was two (2) major events that caused four (4) outages during the month of September due to wind and weather-related activity from monsoon storms. SAIFI including major events was 0.077.

August 2021 Reliability Frequency Index:
There were five (5) localized events causing 5 outages in the month of August. These reportable outages disrupted power to 30 customers and resulted in a “total” SAIFI (frequency) index of 0.002 interruption per customer and was below the target of 0.019 for the month of August based on non-major events. These outages were due to equipment failures, birds and overloads. The average number of customers affected per outage was 6.6. There was three (3) major events that caused nine (9) outages during the month of August due to monsoon storms. SAIFI including major events was 9.948. 

July 2021 Reliability Frequency Index:
There were seven (7) localized events causing 9 outages in the month of July. These reportable outages disrupted power to 130 customers and resulted in a “total” SAIFI (frequency) index of 0.007 interruption per customer and was below the target of 0.086 for the month of July based on non-major events. These outages were due to equipment failures, birds and overloads. The average number of customers affected per outage was 14. There was one (1) major event that caused two (2) outages during the month of July due to a monsoon storm. SAIFI including major events was 0.008. 

June 2021 Reliability Frequency Index:
There were twelve (12) localized events causing 16 outages in the month of June. These reportable outages disrupted power to 2,968 customers and resulted in a “total” SAIFI (frequency) index of 0.172 interruption per customer and was above the target of 0.015 for the month of June based on non-major events. These outages were due to equipment failures, birds and overloads. The average number of customers affected per outage was 186. There were four (4) major events during the month of June due to storms and a car hit transformer accident.  

May 2021 Reliability Frequency Index:
There was one (1) localized outage during the month of May. The reportable outage disrupted power to 15 customers and resulted in a "total" SAIFI (frequency) index of 0.0008 interruption per customer that was below the target of 0.039 for the month of May based on non-major events. The one (1) localized outage in the month of May was due to a blown transformer fuse, due to age. The average number of customers affected per outage was 15. There were no major events during the month of May. 

April 2021 Reliability Frequency Index:
There were four (4) localized outages during the month of April. The reportable outages disrupted power to 33 customers and resulted in a "total" SAIFI (frequency) index of 0.002 interruption per customer that was below the target of 0.007 for the month of April based on non-major events. The four (4) localized outages in the month of April were due to transformer and line fuse failures and a pad mount transformer failure due to age. The average number of customers affected per outage was 8.25. There were no major events during the month of April. 

March 2021 Reliability Frequency Index:
There were two (2) localized outages during the month of March. The reportable outages disrupted power to 9 customers resulting in a “total” SAIFI (frequency) index of 0.0005 interruption per customer that was below the target of 0.028 for the month of March based on non-major events. The average number of customers affected per outage was 4.5. The two (2) reportable outages in March were localized outages due to weather (high winds) and a transformer fuse failure.

February 2021 Reliability Frequency Index:
There were two (2) localized outages as part of one (1) event in February. The reportable outages disrupted power to 41 customers resulting in a “total” SAIFI (frequency) index of 0.002 interruption per customer that was below the target of 0.003 for the month of February based on non-major events. The average number of customers affected per outage was 20.5. The two (2) reportable outages in February were localized outages due to a tree-trimming contractor dropping a limb on an overhead line.

January 2021 Reliability Frequency Index:
There was one (1) localized outage in January. The reportable outage disrupted power to 21 customers resulting in a “total” SAIFI (frequency) index of 0.001 interruption per customer that was below the target of 0.003 for the month of January based on non-major events. The average number of customers affected per outage was 21. The one (1) reportable outage in November was a localized outage due to Failed Termination on a riser switch.

December 2020 Reliability Frequency Index:
There were no outages during the month of December.

November 2020 Reliability Frequency Index:
There was one (1) localized outage and one (1) Major Event totaling two (2) outages in November. The reportable outage disrupted power to 45 customers and resulted in a “total” SAIFI (frequency) index of 0.003 interruption per customer that was below the target of 0.019 for the month of November based on non-major events. The average number of customers affected per outage was 45. The (1) Major Event during the month of November was caused by a mylar balloon in a primary overhead line that resulted in a blown fuse. The one (1) reportable outage in November was a localized outage due to a blown transformer fuse caused by a tree branch.

October 2020 Reliability Frequency Index:
There were three (3) localized outages and one (1) Major Event totaling four (4) outages in October. The three outages disrupted power to 30 customers and resulted in a “total” SAIFI (frequency) index of 0.001 interruption per customer that was below the target of 0.005 for the month of October based on non-major events. The average number of customers affected per outage was 10. The (1) Major Event during the month of October was caused by a mylar balloon in a primary overhead line that resulted in a SF6 switch activating to prevent a circuit outage. The three (3) reportable outages in October were localized outages due to blown transformer fuses (wildlife protection in place) caused by birds.

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 resulted in a “total” SAIFI (frequency) index of 0.08 interruption per customer that 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 cutting into an energized cable resulting in 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 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 resulted in a “total” SAIFI (frequency) index of 0.008 interruption per customer that 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 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 resulted in a “total” SAIFI (frequency) index of 0.009 interruption per customer that 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.




Lost-Time Accidents - Electric
The City of Mesa Electric Utility has gone over 1,172 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 2020 through September 2021:
In accordance with our department's values to work safely, there have been no lost-time accidents from July 2020 through September of 2021 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.