APS Summer Peaks Occurring Later than Ever


At 5:15 p.m., average 2016 peak is 45 minutes later than just four years ago

PHOENIX – APS customers, on average, now reach their summer peak energy usage 45 minutes later in the day than they did just four years ago, according to new data compiled this summer.

In 2012, the average peak for the months of June through August occurred around 4:30 p.m. Skip forward two years to 2014, and the average peak jumped to around 5 p.m. In summer 2016, the average time customers used the most amount of energy over the summer was 5:15 p.m., and high usage continued for several hours beyond that.

The shift of 45 minutes in four years is significant, but not surprising. With the broad adoption of rooftop solar, total energy installed on customer rooftops across the state has doubled, often tripled, year over year. The demand for reliable electricity from APS has changed very little, however, instead shifting to later in the day when the sun is descending and solar power on the grid is declining.

“With customers using more energy later in the evening, the more than 10-year-old on-peak hours of noon to 7 p.m. are outdated,” said Stacy Derstine, APS Vice President of Customer Service and Chief Customer Officer. “We recently requested to change on-peak hours to 3 to 8 p.m. in order to align with the actual periods of highest demand. This would send a better price signal to customers to reduce their energy use at the times when resources are most expensive, providing them more savings – especially to those customers on a demand rate.”

No matter the season or time of day, APS (like all utilities) must plan and build its system to meet the annual peak – the greatest amount of electricity the company must supply to its customers at any given moment. APS will continue to track energy trends (and other data) to ensure reliable energy for customers, but expects the peak to continue to fall later in the day.

APS serves about 2.7 million people in 11 of Arizona’s 15 counties, and is the Southwest’s foremost producer of clean, safe and reliable electricity. Using a balanced energy mix that is nearly 50 percent carbon-free, APS has one of the country’s most substantial renewable energy portfolios, and owns and operates the Palo Verde Nuclear Generating Station, the country’s top power producer and largest producer of carbon-free energy. The company is also a proven leader in introducing technology and services that offer customers choice and control over their energy consumption. With headquarters in Phoenix, APS is the principal subsidiary of Pinnacle West Capital Corp. (NYSE: PNW).

Media Contact:

Analyst Contact:

Jenna Shaver

Ted Geisler

(602) 250-4403

(602) 250-3200

Email Alerts


Enter the code shown above.