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Electric Reliability

The reliability of an electrical system is an aspect that many of us don't appreciate until it starts failing. FPUA recognizes that outages not only cause an inconvenience to residents, but they can also impact the profitability of businesses that rely on us to maintain production or services. This is why FPUA takes a multifaceted approach to maintaining a level of reliability that exceeds our customer's expectations.

Electric utility reliability is gauged using several indicators commonly used by the industry that, in general terms, measure the length and frequency of power outages. The following explains some of the most commonly tracked indicators. In each case, a lower indicator means higher reliability for our customers. A three year trend of FPUA's performance in these areas is presented and compared to Florida Power and Light1 (FPL), our neighboring investor-owned electric utility.

The System Average Interruption Frequency Index (SAIFI) provides the average number of times a customer experiences an outage during the year. In 2013, FPUA customers experienced interruptions at an average rate of 0.51 times per year.


The System Average Interruption Duration Index (SAIDI) measures the cumulative duration of interruptions for the average customer. This is a measure of service unavailability. If all FPUA customers were out of service for the same amount of time in 2013, the total length of interruption would have been thirty-two (32) minutes. Stating it differently, FPUA customers had available power 99.994% of the time.


The weighted average length of an interruption for customers affected during a specified time period can be measured by the CAIDI indicator. CAIDI equals the sum of customer-minutes off for all sustained interruptions.


The time a utility company takes to restore service following an interruption can be measured by the L-Bar indicator. L-Bar measures the average length of time of single service interruptions.


In every case above, FPUA's reliability outperforms that of FPL. Lower rates of interruption and faster response times are only some of the many advantages of having a hometown utility serve you.