Key Performance Metrics

Service Reliability

The North American Electric Reliability Council's definition of reliability encompasses two concepts: adequacy and operating reliability. Adequacy is defined as "the ability of the system to supply the aggregate electric power and energy requirements to the consumers at all times." Operating reliability is defined as "the ability of the system to withstand sudden disturbances such as electrical short circuits." The level of reliability is typically measured by the frequency, duration, and magnitude of the loss of service to total customers.

For the Hawaiian Electric Companies, the most recent four main causes of outages are the following:

  • "Equipment Deterioration" which is mainly attributed to overhead equipment deterioration
  • "Cable Faults" which are due to underground cable system failures
  • "Auto Accidents" which include automobiles and other light vehicles impacting poles and other equipment
  • "Vegetation" which includes downed trees, tree branches in power lines, and overgrown vegetation, some of which falls outside of the Companies' scope of clearance

Other high contributing outage causes were high winds, lightning, heavy rain, and scheduled maintenance which caused service interruptions but not as significantly as the most recent top four outage causes listed above.

The following Service Reliability indices are commonly used in the electric power utility industry as a method of measuring system reliability performance. Consistent with utility practice across the country, reliability metrics shown here for SAIDI, SAIFI, CAIDI, and MAIFI are based on "normalized" data (i.e., excluding atypical events such as system problems due to unusually severe weather). While it is important to measure reliability data for all events, normalized data is more reflective of day to day reliability and generally provides a better indication of reliability and reliability trends.1

1 In 2016, Hawaiian Electric adopted procedures established by IEEE Standard 1366‐2003, and revised in 2012. IEEE Standard 1366, “IEEE Guide for Electric Power Distribution Reliability Indices” was developed to foster uniformity in the development of distribution service reliability indices and to provide tools for internal and external comparisons. In addition to providing definitions for key reliability indices, IEEE‐1366 provides a consistent and objective method for identifying and removing major event days for the purpose of studying reliability under normal daily operation. Q1 and Q2 indices for 2017 have been updated using a consistent methodology based on IEEE-1366 and the latest available outage data.


System Average Interruption Duration Index

System Average Interruption Duration Index (SAIDI) measures the average interruption time for all customers served during a given period of time, typically one year. It is the sum of the restoration time multiplied by the number of interrupted customers for each interruption event divided by the total number of customers served by the company. SAIDI is an indication of overall system reliability because it incorporates the impact of frequency and duration of outages on the Companies' total customer base. To view the calculation formula for SAIDI, click here.

Hawaiian Electric Companies

SAIDI

Hawaiian Electric Company

SAIDI

Maui Electric Company

SAIDI

Hawaii Electric Light Company

SAIDI

Please click the button below for historical normalized and non-normalized data (in Excel format).

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System Average Interruption Frequency Index

System Average Interruption Frequency Index (SAIFI) measures the average number of interruptions experienced by all customers served during a given period of time, typically one year. It is all the customer interruptions divided by the total number of customers served by the company. To view the calculation formula for SAIFI, click here.

Hawaiian Electric Companies

SAIFI

Hawaiian Electric Company

SAIFI

Maui Electric Company

SAIFI

Hawaii Electric Light Company

SAIFI

Please click the button below for historical normalized and non-normalized data (in Excel format).

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Customer Average Interruption Duration Index

Customer Average Interruption Duration Index (CAIDI) measures the average interruption duration per customer interrupted during a given period of time, typically one year. CAIDI is calculated by dividing the sum of all customer interruption durations by the number of customers interrupted during that period. CAIDI can also be found by dividing SAIDI by SAIFI. To view the calculation formula for CAIDI, click here.

Hawaiian Electric Companies

CAIDI

Hawaiian Electric Company

CAIDI

Maui Electric Company

CAIDI

Hawaii Electric Light Company

CAIDI

Please click the button below for historical normalized and non-normalized data (in Excel format).

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Momentary Average Interruption Frequency Index

Momentary Average Interruption Frequency Index (MAIFI) measures the average frequency of known momentary interruptions per customer during a given period of time, typically one year. MAIFI is calculated as the total number of momentary customer interruptions divided by the total number of customers served. The Companies define momentary interruptions as outages that have a duration of one minute or less. To view the calculation formula for MAIFI, click here.

Hawaiian Electric Companies

MAIFI

Note: Hawaii Electric Light did not previously track MAIFI and therefore does not have any historical data. The Company began reporting MAIFI in 2015.

Hawaiian Electric Company

MAIFI

Maui Electric Company

MAIFI

Hawaii Electric Light Company

MAIFI

Please click the button below for historical normalized and non-normalized data (in Excel format).

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Emergency Response Time

The emergency response time metric measures the average time it takes the Companies to respond to an emergency event. The Companies define "emergency event" as an event involving the electric utility equipment that may pose an immediate threat to public safety or welfare. These events may include, but are not limited to: fire calls, dislodged manhole covers, energized lines down (sparking lines), downed poles, motor vehicle accidents involving utility equipment that result in lane closures or possible contact with energized utility lines.

This metric tracks (1) the start time when the utility has adequate and accurate information concerning the emergency event, (2) the average time it takes for the utility personnel to arrive onsite, and (3) the average time to safely and adequately secure the scene from any identified electrical hazard to the public, and to report back to the Companies' operations centers after the scene has been secured. This metric will be tracked in minutes.

The Hawaiian Electric Companies did not previously track the minute intervals for the measures listed above. The Companies began reporting this metric starting in the first quarter of 2015.

Hawaiian Electric Companies

Emergency Response Time

Hawaiian Electric Company

Emergency Response Time

Maui Electric Company

Emergency Response Time

Hawaii Electric Light Company

Emergency Response Time

Please click the button below for historical normalized and non-normalized data (in Excel format).

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