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 July 2022 O&M Cost/Customer was $12.85/Customer
  • 24% below monthly target of $16.97/Customer.
    • July O&M costs were $78,761 less than the forecast used to develop the target.
  • 9% more than June's O&M Cost/Customer of $14.15 per customer.
    • O&M costs decreased 9% from $246,278 in June to $223,135.
Actuals are below target due to emergency line services invoice processing also underspending in material purchases and professional services for items such as SRP billings and tree trimming.

The June 2022 O&M Cost/Customer was $14.15/Customer
  • 16% below monthly target of $16.80/Customer.
    • June O&M costs were $39,940 less than the forecast used to develop the target.
  • 6% more than May's O&M Cost/Customer of $13.37 per customer.
    • O&M costs increased 2% from $232,983 in May to $246,278 in June.
Actuals are below target due to underspending in contract services and open positions.

The May 2022 O&M Cost/Customer was $13.37/Customer
  • 20% below monthly target of $16.80/Customer.
    • May O&M costs were $53,235 less than the forecast used to develop the target.
  • 2% less than April's O&M Cost/Customer of $13.69 per customer.
    • O&M costs decreased 2% from $236,997 in April to $232,983 in April.
Actuals are below target due to underspending in contract services and open positions.

The April 2022 O&M Cost/Customer was $13.69/Customer
  • 19% below monthly target of $16.80/Customer.
    • April O&M costs were $49,221 less than the forecast used to develop the target.
  • 28% less than March's O&M Cost/Customer of $19.01 per customer.
    • O&M costs decreased 28% from $330,912 in March to $236,997 in April.
Actuals are below target due to underspending in contract services for the month of April.

The March 2022 O&M Cost/Customer was $19.01/Customer
  • 15% below monthly target of $22.24/Customer.
    • March O&M costs were $48,054 less than the forecast used to develop the target.
  • 19% more than February's O&M Cost/Customer of $15.96 per customer.
    • O&M costs increased 19% from $276,978 in February to $330,912 in March.
Actuals are below target due to underspending in professional services.

The February 2022 O&M Cost/Customer was $15.96/Customer
  • 5% below monthly target of $16.80/Customer.
    • February O&M Costs were $9,240 less than the forecast used to develop the target.
  • 7% less than January's O&M Cost/Customer of $17.23 per customer.
    • O&M costs decreased 7% from $297,827 in January to $276,978 in February.
Actuals are below target due to underspending in professional services.

The January 2022 O&M Cost/Customer was $17.23/Customer
  • 2.5% above monthly target of $16.80/Customer.
    • January O&M costs were $11,609 more than the forecast used to develop the target.
  • 16% more than December's O&M Cost/Customer of $14.90 per customer.
    • O&M costs increased 15% from $258,816 in December to $297,827 in January.
Actuals are above target due to above average wages from employee retention bonus and professional service for calibration of meter testing hardware.



Electric Reliability -  Outage Duration (SAIDI)

The July 2022 Reliability Duration Index: Target = .82 minutes
  • Actual SAIDI was 0.821 minutes of interruptions per customer.
  • 72% below the monthly target of 2.91.
  • 3 non-major events that caused 3 outages.
  • Average customers affected per outage were 40.
Causes for the three (3) outages were attributed to Equipment Failures/Overloads 66% and Mylar balloons 33%.
  • 7-11-22 – 151 E. 1st Ave Circuit 161, 34 customers for 169 minutes TRANSFORMER FAILURE
  • 7-12-22 – 844 N. Grand Circuit 181, 17 customers for 114 minutes TRANSFORMER OVERLOAD
  • 7-23-22 – 326 E. 7th Dr. Circuit 174, 68 customers for 96 minutes MYLAR BALLOONS
There was one (1) Major Event during the month of July that caused 12 separate outages. Sunday evening on July 17, a monsoon storm combined with high winds and lightning caused several power outages in the Mesa electric service area and beyond. COM crews worked throughout the night on into the next day, making repairs and restoring power to the affected customers. Emergency response contract crews also assisted with the repairs the following day. The July SAIDI including major events was 24.83 minutes.

The June 2022 Reliability Duration Index: Target = .17 minutes
  • Actual SAIDI was 0.17 minutes of interruptions per customer.
  • 91% below the monthly target of 1.87.
  • 6 non-major events that caused 6 outages.
  • Average customers affected per outage were 11.
Causes for the six (6) outages were attributed to birds and other wildlife = 67% and Fuse/Overload issues = 33%.
  • 6-8-22 – 262 N. Pioneer Circuit 234, 24 customers for 48 minutes BIRD
  • 6-10-22 – 331 N. Lesueur Circuit 234, 17 customers for 18 minutes TRANSORMER FUSE
  • 6-11-22 – 625 E. 2nd St. Circuit 234, 1 customer for 11 minutes WILDLIFE
  • 6-16-22 – 950 S. Coleman Circuit 234, 12 customers for 98 minutes BIRD
  • 6-23-22 – 661 E. Marilyn Circuit 232, Fraser North Substation, 10 customers for 17 minutes BIRD
  • 6-28-22 – 734 W. Main Circuit 243, Fraser North Substation, 4 customers for 33 minutes TRANSFORMER FUSE
There was also two (2) Major Events during the month of June that caused nine (9) separate outages. On June 16, a crane contacted energized overhead power lines at 2nd Ave and Hobson. The police report indicated that the driver was leaving the jobsite while the boom of the crane was still in the air, when it contacted the energized line pulling down several spans of overhead lines. Multiple poles were also impacted as a result of the lines being contacted. On June 25, a section of static wire on the 69kV system came in contact with the energized conductors causing the 69kV breaker at the SRP Rogers Substation to open. This breaker is one (1) of the two (2) sources which provide power to the City of Mesa Lewis and Kellwood Substation Transformers. These four (4) transformers provide power to nearly half of COM’s electric grid or more specifically, just over 8,000 customers. Lightning was suspected to be the cause of the event. Shortly after the incident, the 69kV static wire was replaced. The June SAIDI including major events was 24.83 minutes:

•  6-16-22 – 2nd Ave and Hobson Circuit 231, Fraser North Substation CRANE IN OVERHEAD LINES
  • 5 customers for 631 minutes
  • 8 customers for 440 minutes
  • 97 customers for 411 minutes
  • 164 customers for 127 minutes
  • 540 customers for 40 minutes
•   6-25-22 – Rogers 692 Line, STATIC LINE ON 69kV LINE DUE TO LIGHTNING STORM
  • Lewis West Substation, 2312 customers for 43 minutes
  •  Lewis East Substation, 979 customers for 44 minutes
  • Kellwood North Substation, 1,843 customers for 42 minutes
  • Kellwood South Substation, 2,873 customers for 41 minutes

The May 2022 Reliability Duration Index: Target = 4.94 minutes
  • Actual SAIDI was 1.462 minutes of interruptions per customer.
  • 70% below the monthly target of 4.94.
  • 2 non-major events that caused 2 outages.
  • Average customers affected per outage were 471.
  • Causes for the two (2) outages were attributed to Mylar Balloons=100%
  • 5-9-22 – Circuit 232, Fraser North Substation, 926 customers for 27 minutes MYLAR BALLOONS
  • 5-11-22 – 232 E. Millett, Circuit 242, 16 customers for 19 minutes MYLAR BALLOONS
There were also one (1) Major Event during the month of May that caused two (2) separate outages. Mylar balloons contacted an open overhead tie switch where two (2) circuits meet. This fault caused both circuits to trip. The May SAIDI including major events was 3.054 minutes:
  • 5-28-22 – Circuit 211, Robson West Substation, 386 customers for 67 minutes MYLAR BALLOONS (ME)
  • 5-28-22 – 142 W. Main, Circuit 244, 17 customers for 100 minutes MYLAR BALLOONS (ME)

The April 2022 Reliability Duration Index: Target = 1.44 minutes
  • Actual SAIDI was 0.032 minutes of interruptions per customer.
  • 78% below the monthly target of 1.44.
  • 3 non-major events that caused 3 outages.
  • Average customers affected per outage were 7.
Causes for the three (3) outages were attributed to Wildlife (BIRD)=66% and a Switching Error=33%.
  • 4-28-22 – 434 W. Main Circuit 243, 1 customer for 50 minutes LINE FUSE-BIRD
  • 4-28-22 – 600 E. University Circuit 164, 11 customers for 17 minutes SWITCHING ERROR (single phase)
  •  4-30-22 – 67 S. Olive Circuit 231, 10 customers for 32 minutes TRANSFORMER FUSE-BIRD

The March 2022 Reliability Duration Index: Target = 2.39 minutes
  • Actual SAIDI was 0.094 minutes of interruptions per customer.
  • 96% below the monthly target of 2.39.
  • 2 non-major events that caused 2 outages.
  • Average customers affected per outage were 22.
Causes for the two (2) outages were attributed to Wildlife (BIRD)=50%, Weather=50%.
  • 3-27-22 – 612 E. Pepper Pl Circuit 234, 13 customers for 57 minutes TRANSFORMER FUSE-BIRD
  • 3-28-22 – 512 W. 3rd St. Circuit 243, 31 customers for 29 minutes LINE FUSE-WEATHER

The February 2022 Reliability Duration Index: Target = 0.21 minutes
  • Actual SAIDI was 0.00 minutes of interruptions per customer. There were no unscheduled outages during the month of February.

The January 2022 Reliability Duration Index: Target = 0.20 minutes
  • Actual SAIDI was 0.00 minutes of interruptions per customer.
There was one (1) Major Event during the month of January where a mylar balloon contacted the primary overhead line which caused a protected way on a switch to operate and isolate the outage. 567 customers were affected by this event where power was lost for 113 minutes. SAIDI for this Major Event was 3.701 and SAIFI was 0.032. This outage is considered a Major Event and is not used in the calculation for Reliability performance metrics.
•   1-2-22 – 915 S. Mesa Dr. Circuit 232, Mylar Balloon (MAJOR EVENT)


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)

July 2022 Reliability Frequency Index: Target = 0.085 Interruptions per Customer
There were three (3) events that caused three (3) outages during the month of July. These reportable outages disrupted power to 68 customers and resulted in a “total” SAIFI (frequency) index of 0.007 interruption per customer and was below the target of 0.085 for the month of July. There were also one (1) major event that caused 12 outages during the month of July. Sunday evening on July 17, a monsoon storm combined with high winds and lightning caused several power outages in the Mesa electric service area and beyond. COM crews worked throughout the night on into the next day, making repairs and restoring power to the affected customers. Emergency response contract crews also assisted with the repairs the following day. The July SAIFI including major events was 0.514 minutes.

June 2022 Reliability Frequency Index: Target = 0.039 Interruptions per Customer
TBD.

May 2022 Reliability Frequency Index: Target = 0.039 Interruptions per Customer
There were two (2) localized events causing two (2) outages during the month of May. These reportable outages disrupted power to 22 customers and resulted in a “total” SAIFI (frequency) index of 0.054 interruption per customer and was above the target of 0.039 for the month of May. These outages were all due to mylar balloons contacting overhead power lines. The average number of customers affected per outage was 942. There was also one (1) Major Event during the month of May that caused two (2) separate outages. Mylar balloons contacted an open overhead tie switch where two (2) circuits meet near the Robson Substation. This fault caused both circuits to trip. The May SAIFI including major events was 0.07 minutes.

April 2022 Reliability Frequency Index: Target = 0.007 Interruptions per Customer
There were three (3) localized events causing three (3) outages during the month of April. These reportable outages disrupted power to 22 customers and resulted in a “total” SAIFI (frequency) index of 0.001 interruption per customer and was below the target of 0.007 for the month of April based on non-major events. These outages were due to blown fuses from birds and a switching error. The average number of customers affected per outage was 7.3. There were no major events during the month of April.

March 2022 Reliability Frequency Index: Target = 0.028 Interruptions per Customer
There were two (2) localized events causing two (2) outages during the month of March. These reportable outages disrupted power to 44 customers and resulted in a “total” SAIFI (frequency) index of 0.003 interruption per customer and was below the target of 0.028 for the month of March based on non-major events. These outages were due to blown fuses from a bird and bad weather. The average number of customers affected per outage was 22. There was no major events during the month of March.

February 2022 Reliability Frequency Index: Target = 0.003 Interruptions per Customer
There were no reported unscheduled outages for the month of February.

January 2022 Reliability Frequency Index: Target = 0.003 Interruptions per Customer
There was one (1) Major Event during the month of January where a mylar balloon contacted the primary overhead line which caused a protected way on a switch to operate and isolate the outage. 567 customers were affected by this event and power was lost for 113 minutes. SAIDI for this Major Event was 3.701 and SAIFI was 0.032. This outage is considered a Major Event and is not used in the calculation for Reliability performance metrics.
•   1-2-22 – 915 S. Mesa Dr. Circuit 232, Mylar Balloon (MAJOR EVENT)


Lost-Time Accidents - Electric
The City of Mesa's Electric Utility has not had a lost-time accident since 8/13/2018. In the 2021 calendar year, it did have one occupational injury that resulted in 11 days of job transfer/restricted duty and one work-related illness that resulted in 10 days away from work. 
In accordance with our department's values to work safely, employees continue to communicate and use safe working practices as part of the daily activities, and safety topics are covered in the weekly tailgate sessions, as well as the monthly department meetings.