Some Washington utilities saw all-time usage highs in the historic heat, and a state commission is investigating their preparedness after planned outages

The Washington Utilities and Transportation Commission will investigate how utility companies prepared and responded amid record-setting heat statewide earlier this week that led to all-time usage highs and planned outages for some of them.

As part of the investigation, the commission will look into utility infrastructure and customer communications related to the heat wave, which saw record-high temperatures across much of Eastern Washington, said Emilie Brown, a commission spokesperson. The results of the investigation, which will likely take anywhere from six to 18 months , will be posted publicly with gathered documentation.

“Staff can make recommendations in their investigation report for the Commission to consider,” Brown said in an email, “and ultimately the Commission will decide what measures to take both for the recent event and to prepare for similar events in the future.”

The commission has asked utilities to address weather patterns, and how those impact demand and load, in their integrated resource plans, Brown said.

The required plans, updated every two years, share how utilities will obtain future energy resources for customers at the lowest cost to ratepayers, she said.

“Commission staff thoroughly review those plans, and any staff recommendations or Commission orders that come out of those reviews will be posted in the appropriate dockets,” Brown said.

While the National Weather Service’s forecast through Wednesday for Spokane shows temperatures in the 90s, triple-digit heat earlier this week resulted in record-high system loads for several utility companies across the Inland Northwest.

Representatives with Avista Utilities, which provides electrical service to 400,000 customers across parts of Washington, Idaho and Oregon, have said the company’s load Monday would have exceeded the previous systemwide peak of around 2,300 megawatts by “several hundred megawatts.”

That day, approximately 24,000 customers lost power as Avista implemented rolling blackouts in areas where the system was the most stressed. Additional blackouts took place Tuesday.

Meanwhile, the 110.9 megawatts recorded around 3 p.m. Tuesday was a record-high summer load for the Kootenai Electric Cooperative, which serves more than 30,000 meters in parts of Kootenai, Benewah, Bonner and Spokane counties.

Vera Water and Power, which services 12,800 meters in Spokane Valley, reached an all-time summer peak load that same day with 58.11 megawatts. That’s up from 49.46 megawatts July 31, 2020, when temperatures in Spokane reached 102 – the city’s hottest day of the year.

Tuesday reached 109 degrees in Spokane, the highest temperature ever recorded in the city. It was 105 on Monday.

Heather Rosentrater, Avista’s senior vice president for energy delivery, previously said the electrical system Monday reached threshold limits faster than anticipated, while some of the system’s infrastructure was unable to operate as planned.

Avista customers were not alone in contending with unplanned outages, however.

A total of 933 Kootenai Electric Cooperative customers were affected by unplanned heat-related outages Sunday, said spokesperson Erika Neff. Another wave of heat-related outages Monday affected 1,252 customers.

In all instances, Neff said the power was restored by adjusting equipment settings to accommodate the load.

“The cooperative’s substations and feeders have performed without capacity issues or power supplier and transmission constraints this week,” Neff said in an email. “With the unprecedented temperatures, some isolated areas on the distribution system experienced outages due to extreme load above what was forecasted in the engineering model.”

Inland Power and Light, Northern Lights Inc. and Vera Water and Power did not sustain any heat-related outages, representatives said. The Pend Oreille Public Utility District similarly reported no outages due to the hot weather, “other than for a few small fires.”

Amber Gifford, a spokesperson for the public utility district, said the district’s system “doesn’t get overly stressed during summer heat.”

“Only about 25% of our customers have air conditioning. We did have work scheduled prior to the heat wave and we assured that all the equipment was back in normal service,” Gifford said. “Our winter load is still higher than the load experienced in the heat wave.”

Inland – which serves more than 43,000 meters in 13 counties across eastern Washington and North Idaho – also has peak usage in winter, typically in late January/early February, said Inland spokesperson Jennifer Lutz.

“We monitor our system 24/7 and determined our system was in good shape,” Lutz said in an email, noting none of the “minimal” outages Inland experienced since Saturday were weather-related. “We did not have any discussions on blackouts as we did not see that as an action we would need to take this week.”

Area utility companies, including Northern Lights Inc. and Kootenai Electric Cooperative, used past load data to prepare for the heat wave.

Kristin Mettke, engineering and operations manager with Northern Lights, said the utility kept an eye on equipment that was heavier loaded than historical levels. Meanwhile, Northern Lights line crews were among the many utility workers who started earlier in the day to avoid the peak afternoon heat.

Kootenai Electric Cooperative analyzed eight-year historical load data to help plan ahead for the heat wave. That same data is used by the utility to develop a growth trend forecasting the next four years. As such, the cooperative has various projects in the works from now through 2024, including a new substation.