Extreme Heat and Aging Power Grids Are a Deadly Combination
As temperatures hovered over 110F (43C) for a fourth consecutive week in Phoenix, heat-related illness calls for emergency services spiked to more than double the level seen at this time last year.
The numbers illustrate just how fragile humans are in extreme heat. And this single indicator showing the limit of human endurance shot up at a time when power systems functioned well and no blackouts occurred.
Last year, Europe experienced over 60,000 heat-related deaths due to uncharacteristically hot weather, according to a recent analysis. The problem was, in part, a lack of cooling infrastructure. But it suggests the fatalities that might occur in the US after a prolonged grid failure.
In other words, things could be much worse.
Blackouts and heat are a deadly combination. Half the population of Phoenix would land in the emergency room if a multi-day blackout struck during a heat wave, and nearly 13,000 people would die, according to a study published in May in the journal Environmental Science and Technology.
Most people in the US tend not to worry about blackouts because they still tend to be fairly uncommon and brief. Even in Phoenix, with its record-breaking stretch of daily highs at or above 110F, the grid is holding.
But that’s not a sure thing going forward. Last week the largest US grid — serving 65 million customers from Washington, DC to Illinois — issued an emergency alertraising concern about its ability to maintain enough power reserves as people crank up their air conditioners.
Fragility is commonplace across US energy infrastructure. “The wires and poles are getting older, and the weather is getting more difficult, and the population’s getting bigger,” says Michael Webber, a professor of energy resources at the University of Texas at Austin.
Most big blackouts in the US are triggered by storms physically damaging the grid — ripping down power lines, snapping poles or flooding substations. But extreme temperatures, hot or cold, can turn out the lights, too. Winter Storm Uri in February 2021 froze gas pipelines across Texas and knocked out power plants whose owners had ignored prior warnings to weatherize their gear. Roughly 4.5 million homes and businesses went dark in sub-freezing temperatures, many of them without electricity for days. More than 200 people died.
Federal data shows that in recent years, as increasingly extreme weather driven by climate change collides with an aging grid, blackouts have been happening more often and lasting longer. A decade ago, the average US home experienced a sustained outage 1.2 times per year, lasting three hours on average, according to the US Energy Information Administration. In 2021 — the most recent year for which data is available — the average number of blackouts per customer had risen to 1.4, with the power out for more than 5 hours.
Emergency managers are acutely aware of the threat. “Electricity is really the cornerstone of disaster recovery,” said Bryan Koon, vice president of homeland security and emergency management at IEM, a disaster management consulting firm. “When you don’t have it, everything is hard. When you have it, everything becomes a little bit easier.”
That said, it’s not the government’s job to restore power, it’s utilities’. While they do their work, most of us rely on backups that kick in in stages.
Immediately after an outage, the first and foremost line of protection is privately owned small generators. Many hospitals and nursing homes are required to have their own. This is in part because of Hurricane Irma in 2017, which knocked out power to more than 6 million Floridians. A dozen people died in a Hollywood, Florida, nursing home due to lack of air conditioning.
There are a lot of generators out there, but still not nearly enough to keep an entire city cool in the midst of the kind of heat waves that are fast becoming the new normal. And most generators still burn fossil fuels, which not only contribute to global warming that is making the heat worse in the long run, but may be hard to acquire in an emergency situation.
Most localities also have some backup generators, or contracts for private generators and fuel suppliers to come to their aid if necessary. However, getting this system into place can take hours or days. And once it’s deployed, officials have to make decisions on which critical infrastructure to prioritize. Power at this point is very limited and competition for it is steep. Cooling centers for the general populace have to fight it out with water and sewage plants and law enforcement.
The next biggest challenge, says Ron Coleman, a spokesman for the emergency management office of Maricopa County, Arizona, is reaching unhoused and low-income residents, who may not have the resources to help themselves. County data from 2022 shows that the biggest culprit in that year’s indoor heat deaths wasn’t a lack of air conditioning, but AC units that were broken.
This month emergency rooms in Arizona have seen an influx of patients with burns from falling on scorching asphalt. Many were elderly or unhoused or were working outside and overcome by the heat. Hospitals in Phoenix are also treating some people with heat illness by immersing them in body bags filled with ice to lower their body temperature.
Maricopa County experienced some of the highest temperatures in the nation in July, joined by Arizona’s Yuma, La Paz and Pima counties, Eddy County in next-door New Mexico and most of southern Texas along the border with Mexico. And Maricopa is one of the fastest-growing places in the US — meaning that, worryingly, more Americans are moving into harm’s way.
If an urban area’s power outage were to extend over a long period of time, more resources could be brought to bear. Both state and federal emergency management services could be called in and would have enough generators at their disposal that they could power a stadium-sized cooling center. And though it would take far longer, the US Army Corps of Engineers could be tasked with building a backup emergency power system. After Hurricane Maria knocked out power to 1.5 million people in Puerto Rico, the Corps assisted local authorities with rebuilding the grid, supplied generators and even erected microgrids in remote parts of the island. But the power was still out for months.
In theory, in Maricopa, healthy people with resources have the ability to flee if the situation is life-threatening. “Flagstaff is only two hours away,” Coleman says, referring to the city which has a higher elevation and therefore is usually cooler than greater Phoenix.
It’s likely that many would do just that, but fleeing requires forethought. Many home garage openers and pumps at gas stations are powered with electricity. And how Flagstaff or other Western cities would manage hundreds of thousands of refugees from Phoenix is anyone’s guess.
As heat danger spreads, there are fewer safe harbors to run to. Where heat mortality is worse does correlate with high temperatures — but not precisely. Multiple other variables are likely at play, including demographics and built environment factors such as the extent of tree cover in neighborhoods.
While the American emergency response system is robust, it still might not be adequate to the task. “We are not anywhere prepared enough,” says Samantha Montano, an assistant professor of emergency management at Massachusetts Maritime University. “On an individual level, if you lose electricity, there is not a lot you can do to mitigate the problem.”
Whether it is fire or hurricanes or flooding or heat that poses danger, emergency management professionals advise that it is always better to make your own preparations. Have adequate insurance, water on hand, gas to fill the tank and a personal plan for staying cool if all else fails.