Microgrids and Energy Storage Helped Arizona Utility Prevail on Hot & Dark Days

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It’s been a tough year for North American electric grids — hurricanes, heat, fires, an eclipse. But an Arizona utility is reporting that it did just fine with some help from new microgrids and energy storage.

“Driving past a microgrid or energy storage unit, many customers wouldn’t look twice, but those technologies are playing an increasingly important role in delivering efficient energy on the hottest days of the year,” said Jacob Tetlow, vice president of transmission and distribution operations at Arizona Public Service (APS), which serves about 2.7 million people.

APS recently developed a 25-MW military microgrid operating at an air station in Yuma, Arizona and a 63-MW data center microgrid in Phoenix for Aligned Data Centers. The utility uses a business model where microgrids provide grid services when they are not acting as islanded back-up generation for their hosts.

The microgrids came into operation in time to help the utility navigate record high temperatures. The Phoenix metro area experienced the third hottest June, with a peak of 119 degrees on June 20, so hot that commercial aircraft were grounded.

The heat drove electric demand to a new high of 7,367 MW, breaking the previous record of 7,236 MW set in 2006. And as planned, the microgrids kicked in to assure that supply met demand, providing power to surrounding communities.

Meanwhile, energy storage showed its worth for APS during the August 21 solar eclipse. The event evoked a great deal of talk nationwide about the loss of solar power as the moon totally blocked the sun. In the Arizona cities of Surprise and Buckeye, batteries helped ensure reliability as solar output dropped substantially, according to the utility. The batteries also supply power within the communities during the evening.

The utility plans to install additional energy storage, this time in Punkin Center, where batteries will avert the need to rebuild 20 miles of power lines. APS describes the project as one of the first of its kind in the nation. The utility expects to begin using the battery units in summer 2018

The microgrids and energy storage were reinforced by the utility’s new advanced distribution management system (ADMS), designed to increase grid resiliency and shorten outages. The advanced operating system increases the utility’s visibility and accessibility to power lines across the state.

The system also helped APS control power lines remotely during the Goodwin fire in June, which burned tens of thousands of acres of national forest. The utility said that its crews worked with state and local officials to de-energize power lines and later re-energize them after the fire was extinguished.

“Our customers’ needs are changing, technology is progressing and APS is ready for both,” said Tetlow. “Thoughtfully implementing these technologies makes our grid smarter, faster and stronger.”

The utility also credited a diverse mix of traditional resources in helping ensure reliability during difficult times in 2017. These include existing nuclear power and quick-start natural gas-fired plants.

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About Elisa Wood

Elisa Wood is the chief editor of MicrogridKnowledge.com. She has been writing about energy for more than three decades for top industry publications. Her work also has been picked up by CNN, the New York Times, Reuters, the Wall Street Journal Online and the Washington Post.


  1. Eric Ackerman says:

    Hi Elisa. I’d like to invite you to cover a mini-summit on Puerto Rico. October 27 on capital hill. Send me an email and I’ll send you the details.

    Eric Ackerman


  1. […] Arizona Public Service won approval for cost recovery for two microgrids and over the summer experienced the fruits of the technology when record high temperatures put the central grid under strain. […]