It’s a Saturday morning and all around the grounds of the Desert Palm United Church of Christ in Tempe are tables with information about the city’s emergency preparedness initiatives. At one booth, a big poster asks: What do you think is the biggest risk our community faces?
Participants weigh in by placing a sticker next to categories like public health outbreaks, food insecurity or air quality. But the threat that has gathered the most stickers is extreme heat. That’s where longtime church member Kathy Lange puts her sticker, too.
“It’s a biggie, and there’s a lot of people that would need help with that, especially the homeless,” Lange said.
Extreme heat is also one of the biggest concerns for Tempe officials. That’s part of the reason for this event. The city is planning to create a network of trusted, neighborhood spaces, like this church, to serve as Resilience Hubs – buildings that would be prepared to open their doors in a disaster, specifically, a widespread power outage during a heat wave.
Tom Martinez is senior pastor here. He said the concept fits right in with the church’s mission to serve the community.
“We said, ‘Absolutely, yes, let’s have a conversation,’” Martinez said.
This summer was the hottest on record in the Valley, and local governments are grappling with how to respond to the growing threat of extreme heat. In Tempe, Resilience Hubs are a key part of the city’s climate plan. Eventually, Tempe officials want some of these hubs to have back-up power sources, so that if a major power outage ever occurred during triple-digit temperatures, the city would have a network of buildings where food could stay refrigerated, phones and emergency equipment could stay charged, and residents could come to escape dangerous heat.
Martinez said Tempe has already begun assessing how the Desert Palm United Church of Christ building could be retrofitted to offer such emergency services.
“Engineers from the city of Tempe have come, and they’ve looked at the electrical system to see what might be required if there were a major power outage, how could we power up the air conditioner, turn this into a place of respite, a sanctuary,” Martinez said. “Pun intended.”
The city may start by providing traditional generators for some Resilience Hubs, but in the long term, the idea is for these spaces to operate as microgrids – meaning they would have solar panels and also battery storage that could connect to the main power grid, but could also function independently, even if the greater grid experienced an outage.
“It’s really just making sure that we’re diversified in the city of Tempe so that we can stand up in the event of a disruption,” said Carissa Fowler, Tempe’s heat mitigation and resilience coordinator. “We want to make sure that our facilities that offer essential services, that offer services related to shelter or can operate during an emergency, we want to make sure that they’re backed up so they can operate in that way.”
Heat kills hundreds of people in Maricopa County every summer. But a 2023 study in the journal Environmental Science & Technology found if a multi-day power outage were to knock out air conditioning for Phoenix during a heat wave, nearly 13,000 people would die and about 800,000 more would need emergency care.
The authors of the study stressed the scenario is extremely unlikely. Major utility providers in the Phoenix area also say they are well prepared to prevent such a disaster.
“But [Tempe officials] really just want to make sure that we’re prepared anyways,” Fowler said. “We’re entering new territory with climate change. It’s going to keep getting hotter, and I think even now we’re seeing the effects a little bit sooner than we thought we were going to.”
While major blackouts are still rare, the study showed climate change-driven natural disasters are making these events more common. Outages impacting more than 50,000 customers for over an hour more than doubled in frequency from 2015 to 2020, the study found.
“It seems as though, given the increases and intensity of the heat, that even though the probability is low, it’s getting higher,” said Nate Johnson, director of Arizona State University’s Laboratory for Energy And Power Solutions, or LEAPS, which researches microgrid technology and provides workforce training for the microgrid industry.
Amid this summer’s relentless heat, major Phoenix-area utilities reported record-breaking energy demand. Johnson said local utilities – and municipalities like Tempe – are feeling more pressure to come up with plans for how they would respond if electricity and air conditioners were to be interrupted in summer.
“For a few minutes, that’s annoying; if it’s hours, that’s unpleasant; but if it’s days, it’s deadly,” Johnson said.
Tempe’s plan to mitigate the risks of a potential summer outage by installing microgrid systems for several Resilience Hubs around the city would likely cost millions. Fowler’s office is currently putting together a feasibility study to calculate the costs and logistics of establishing the microgrids. Her office plans to present the study to Tempe City Council in the spring.
Fowler thinks federal grant money could put the technology within reach, and she thinks city leaders have a real interest in strengthening local-level disaster preparation.
“We’re entering new territory with climate change. It’s going to keep getting hotter, and I think even now we’re seeing the effects a little bit sooner than we thought we were going to.”Carissa Fowler, Tempe’s heat mitigation and resilience coordinator
“Right now, our current emergency management system – FEMA, Red Cross – it’s very top-down,” Fowler said. “We’re really trying to create a local approach to emergency management by tapping into what’s already available in the community.”
Johnson said he thinks preparing for disasters at the local level is wise. And he said Tempe is not the only entity doing it.
Microgrids still account for just a small fraction of the country’s energy production. But microgrid capacity in the U.S. has been increasing by more than 30% per year, according to the renewable energy data analytics firm Wood MacKenzie. The boom is driven by investments coming from a range of industries, Johnson said.
“Data centers, casinos, community buildings and properties, military bases, you name it,” Johnson said.
While the technology is costly, Johnson said even if microgrid systems are never needed for a disaster, they can still generate power that goes back into the main grid the rest of the time.
“One of the best value propositions of a microgrid is, it’s not just an emergency asset; it provides value all the time,” Johnson said.
Back at the Desert Palm United Church of Christ, Martinez said Tempe’s plan to coordinate churches and other community sites as Resilience Hubs could also provide year-round value.
“It’s not just waiting until there’s a disaster,” Martinez said. “It’s recognizing that if we can make ourselves stronger now by pulling together, meeting our neighbors, creating some pathways of communication, then we’re going to be more resilient when there is a disaster.”
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