LEILA FADEL, HOST:
During the intense heat of the last few summers, utilities in the Phoenix area saw record high demand on the power grid. Katherine Davis-Young from member station KJZZ reports on a new tactic from the utilities to manage the load.
KATHERINE DAVIS-YOUNG, BYLINE: In Irina Levin's house in Tempe, Arizona...
(SOUNDBITE OF DOOR KNOCKING)
IRINA LEVIN: Hey.
DAVIS-YOUNG: Hello. How you doing?
She has a shiny Google Nest mounted on the wall of her hallway.
LEVIN: That's it (laughter).
DAVIS-YOUNG: It's a typical air conditioning system, except for the way her utility company, Salt River Project, sometimes uses it.
LEVIN: They can take control of our thermostat.
DAVIS-YOUNG: Maybe that sounds a little spooky, but this is an increasingly common way for utilities to manage energy demand. Six or seven times throughout the summer, the utility remotely turns the temperature down a little to pre-cool Levin's house. Then in the afternoon when it's really hot and the grid is under the most strain, SRP dials Levin's temperature up about 4 degrees hotter than she'd usually set it so her AC stops blowing full blast for a couple hours.
LEVIN: Sometimes we're just not home, so it's not really a thing. But if we're home, I've never been like, no, no, no, this is too hot.
DAVIS-YOUNG: She can ramp the AC back up but usually waits until the conservation event is over to do that. SRP gave her $50 to sign up for the program and pays her 25 for each year she stays enrolled. Levin's thermostat is one of more than 100,000 devices SRP can now adjust this way. SRP's Casaundra Donahoe says turning the AC down in all those households allows the utility to conserve up to 125 megawatts at a time.
CASAUNDRA DONAHOE: Which is enough to power around 50,000 homes, depending on their energy usage.
DAVIS-YOUNG: Arizona's three biggest utilities all have programs like this now, and they offer similar incentives to commercial customers. Even the local NFL stadium takes part. They're all trying to keep up with population growth and intensifying summer heat. SRP projects demand will soar 50% in the next decade. Traditionally when utilities plan for growth, they build more power plants, says Michael Webber, a professor of energy resources at the University of Texas.
MICHAEL WEBBER: We build this whole system to meet that peak demand. And that's really expensive because on average, we use the grid like 50% of the time because we don't have it that hot all the time.
DAVIS-YOUNG: But if utilities couldn't meet those highest loads, they'd risk blackouts, which could be deadly during a heat wave. So Webber says it makes sense for utilities to look for ways to turn down demand. Smart thermostats offer an easy solution.
WEBBER: It's really just a few hours of a few days of the year, and the benefits are really tremendous.
DAVIS-YOUNG: Electric providers nationwide are catching on, says Jessie Guest. She's with EnergyHub, a company that makes the software utilities use to manage these programs. Guest says in a decade, EnergyHub's clientele has grown to include 80 utilities.
JESSIE GUEST: We're in Arizona, California, now Oregon. We're in the Midwest, we're in Florida, New England.
DAVIS-YOUNG: The Phoenix area program is one of the largest. Even so, only about 10% of SRP customers have enrolled since its launch five years ago. Some customers just might not want to give up control of the AC, even just a few days a year. And Webber says the incentives for these programs tend to be small.
WEBBER: If they pay, they don't pay very much.
DAVIS-YOUNG: But he thinks utilities should double down on growing these programs because whatever it might cost to pay incentives to get more customers enrolled would still be much cheaper than building new power plants. And that, he says, would save all customers money.
For NPR News, I'm Katherine Davis-Young in Phoenix.
(SOUNDBITE OF BOREAL MONKEY'S "FEAR AND FORCE") Transcript provided by NPR, Copyright NPR.
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