MARY LOUISE KELLY, HOST:
The country's fifth-largest city, Phoenix, is enduring its longest heat wave in recorded history, and that is driving record-breaking demand for electricity. Katherine Davis-Young from member station KJZZ visited a power station to see how utilities are keeping up.
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KATHERINE DAVIS-YOUNG, BYLINE: For one Phoenix-area utility, Salt River Project, more than three weeks of temperatures above 110 have meant turning on extra natural gas turbines.
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DAVIS-YOUNG: Bob Ellis is the plant director at SRP's Agua Fria Generating Station. This is where SRP turns for additional power when the system sees peak demand. The oldest turbines have been here since the late 1950s. And while they still work, they take 12 to 14 hours to power up.
BOB ELLIS: You've got a big hunk of steel - that steam turbine - and you have to warm that up. And you have to make sure it's evenly warmed before you actually put it online.
DAVIS-YOUNG: SRP can predict when they'll need extra power, but they can't always plan hours ahead. So this year, SRP installed two new turbines at this plant. Ellis says those can start generating enough power for 22,000 homes in under 10 minutes. Ellis says that helps SRP be better prepared for disruptions.
ELLIS: We get a lot of fluctuations from maybe another power plant trip. It could be a monsoon that came in and wiped out a bunch of transmission lines. But we use these to smooth out the grid.
DAVIS-YOUNG: That's crucial, especially this summer. This is the longest heat wave in Phoenix history. Daytime temperatures have hit 119, and overnight lows have hovered in the 90s. SRP and Phoenix's other utility, APS, have both reported the highest power use ever.
PAM SYRJALA: Air conditioning is probably one of our single largest loads.
DAVIS-YOUNG: Pam Syrjala is with SRP. She says it's not just that summers are getting hotter. The metro-area population has also more than doubled in 30 years. To meet growing demand, power companies say they're relying on a mix of sources, from renewables to natural gas.
SYRJALA: No one resource really solves the whole energy need, so you have to make sure that you have the right mix of resources in your portfolio to ensure reliability.
DAVIS-YOUNG: That's why, Syrjala says, SRP continues to look for ways to add backup power to that mix, like the new turbines at the Agua Fria plant. They're also investing in battery storage that could keep homes powered if other sources were disrupted because, if Phoenix did experience a power outage during this heat, the results could be catastrophic. A recent study in the journal Environmental Science & Technology found, in that worst-case scenario, nearly half the city's population would need emergency care. Nearly 13,000 would die.
DAVID HONDULA: In hot cities, air conditioning is a critical lifeline.
DAVIS-YOUNG: David Hondula directs Phoenix's Office of Heat Response and Mitigation, and he was among the study's co-authors. According to the study, extreme weather and natural disasters nationwide are making blackouts more common than they used to be. But Hondula doesn't expect Phoenix will see a deadly power outage anytime soon.
HONDULA: We're talking about slivers of a fraction of a percent of possibility.
DAVIS-YOUNG: Still, Hondula says the study serves as a reminder that lowering temperatures even a few degrees could save lives. That's why he wants Phoenix to plant more shade trees and increase the use of cool-roof technology.
HONDULA: A cooler city would be a much safer one - a much more protective one against adverse impacts from this type of event.
DAVIS-YOUNG: Climate change is making heat waves more intense and more frequent, and Phoenix's population is still growing. Hondula says that's why the city will have to continue to find ways to adapt beyond just AC.
For NPR News, I'm Katherine Davis-Young in Phoenix. Transcript provided by NPR, Copyright NPR.
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