Tucson Electric Power’s service was more reliable last year than ever before as we rose to the challenge of serving our customers’ energy needs amid record-setting heat and a public health crisis.

TEP, which ranks in the top quartile of all electric utilities across the country for our reliability scores, just wrapped up our best year on record, with 99.99% reliability.

TEP tracks the duration of outages attributed to maintenance, equipment failure, weather and other factors with a metric called the System Average Interruption Duration Index, or SAIDI. Essentially, the metric represents how many minutes, on average, each customer spent without power over the course of a year.

After posting a SAIDI of 65 minutes in 2017, we improved our scores in 2018 and 2019 to 51 and 54 minutes, respectively. In 2020, despite record heat that placed constant stress on our infrastructure and equipment, we achieved a SAIDI of 48 minutes. That’s three minutes better than our previous record.

About 34 percent of our customers had zero outages last year. Of those who did, their outages averaged 73 minutes. Average customer outage times have been reduced by about 17 minutes over the past few years.

In addition to a mild monsoon storm season, several key prevention programs helped us achieve those remarkable results in 2020.

“We’re constantly seeking ways to help us improve our system so we can deliver even better results for our customers,” said David Wagner, Director of Line Construction and Metering. “It’s a testament to the programs we have in place, but also to the skill and expertise of our teams.”

Visual inspections of our local energy grid help us identify potential problems before they can cause outages. Patrollers evaluate every one of the 109,000 poles in our distribution system, identifying about 270 high priority repairs over the past two years. “This proactive approach helps us identify and address potential issues, so we can continue to minimize service disruptions,” Wagner said.

TEP’s investments in grid upgrades play a large role in our reliability, as does a comprehensive evaluation of outages to detect trends. We have gained process efficiencies and expanded our replacement of wood poles with sturdier steel poles over the past few years as well.

“We’ve predicted that the effects of these programs will be cumulative each year, as we continue to meet or exceed our goals to decrease the number and duration of outages, and so far, that has proven true,” Wagner said. “We’re really proud of the results we’ve been able to achieve.”

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