Engineers Ranked Every U.S. City’s Power Grid by Climate Resilience – This One Came in Dead Last

Sharing is caring!

Every summer, the same pattern repeats. Temperatures spike, air conditioners strain the system, and somewhere in the country the lights go out at the worst possible moment. Engineers and researchers have spent the past few years trying to quantify exactly which cities are most likely to see their grids buckle under climate pressure, and the answers are not always where you’d expect. Using outage data, infrastructure age, storm exposure, and utility investment records, a rough hierarchy has emerged among major U.S. cities. Some places have poured money into hardening their systems. Others have deferred maintenance for decades and are now paying for it in extended blackouts. One city, in particular, stands out as a cautionary tale for the entire country.

How engineers actually measure grid resilience

Grid resilience scoring typically blends several data streams rather than relying on a single metric. Researchers look at outage duration and frequency, then weigh that against the severity of local weather threats, from heat domes to hurricanes to ice storms. The methodology often relies on explainable A.I., a machine learning approach that weighs outage frequency, intensity, and duration to produce a county-by-county score.

The trend lines are not encouraging for most of the country. Since 2019, outage duration, frequency, and scale have increased by around 20 percent annually. Analysts also note that the problem is not purely a weather story. Non-weather factors, including aging electrical grids, rising energy demand, and urban development density, also play a major role.

Phoenix, Arizona: heat that outlasts the grid’s design limits

Phoenix sits near the top of most vulnerability lists for an obvious reason: it gets brutally hot for months at a time, and its grid was largely built for a milder climate. When outages coincide with heat waves, the danger multiplies fast. In Atlanta, Detroit, and Phoenix, between 68% and 100% of the population would face elevated risk of heat exhaustion or heat stroke during a combined blackout and heat wave.

Thermoelectric generation, which still supplies most of the country’s power, loses efficiency exactly when demand peaks. Thermoelectric power plants that rely on steam to spin a turbine account for over 70 percent of total U.S. power generation and are especially vulnerable to increasing heat, since turbines lose efficiency as ambient temperatures climb. For a desert city like Phoenix, that mismatch between supply and demand is not a hypothetical, it happens most summers.

Houston, Texas: an isolated grid with two failure modes

Houston’s grid problems get less attention than New Orleans’ but the underlying vulnerability runs just as deep. The city’s utility, CenterPoint, has become something of a case study for resilience investment after repeated storm failures. The Power Resilience Forum, sponsored by CenterPoint, took place in Houston from January 21 to 23, 2026, as part of a broader industry push toward resiliency.

Texas’s grid isolation, run separately from the rest of the national interconnection, means the state has fewer options to import power during a crisis. Winter Storm Uri in 2021 exposed that weakness in brutal fashion, and summer heat waves have stressed the same system from the opposite direction ever since. Houston illustrates a city caught between two extremes, neither of which its infrastructure was built to withstand comfortably.

Atlanta, Georgia: heat and storms compounding each other

Atlanta’s risk profile is unusual because it combines two distinct hazards rather than just one. The city faces both severe heat exposure and a growing frequency of storm-driven outages, and researchers have flagged it repeatedly as a compound-risk city. Atlanta appears alongside Detroit and Phoenix as a city where a combined blackout and heat wave would put a majority of the population at elevated risk of heat illness.

What makes Atlanta’s case notable is how quickly things can spiral once the grid fails during a heat event. Air conditioning is not a luxury during a Georgia summer, it’s closer to a medical necessity for many residents. When both hazards land at once, recovery windows shrink and the health consequences climb.

Detroit, Michigan: an aging grid in a changing climate

Detroit’s grid struggles stem less from a single dramatic disaster and more from decades of underinvestment in aging equipment. Its inclusion among the highest-risk cities for combined heat and blackout scenarios reflects that vulnerability. Detroit is named alongside Atlanta and Phoenix as a city where the majority of residents would face elevated heat risk during a simultaneous blackout and heat wave.

Unlike Sun Belt cities, Detroit’s grid also has to handle harsh winters, which adds a second layer of stress that many hotter cities don’t face. That dual exposure, brutal summers paired with genuinely dangerous winters, means the margin for error on aging infrastructure is thinner than it looks on paper.

Chicago, Illinois: derechos, ice, and a grid built for a different era

Chicago and the broader Midwest have seen some of the most damaging storm events of the past decade, according to independent grid analysis. Over the last decade, extreme weather events were the cause of the top 10 worst power outages in the central United States, according to analysis by the Union of Concerned Scientists. Derechos, in particular, have become a recurring threat that older transmission infrastructure wasn’t designed to absorb.

The region’s grid operator has acknowledged the scale of the challenge ahead. As climate change brings about more frequent and intense extreme weather events in the coming years, electrical grid operators such as the Midcontinent Independent System Operator, states and utilities must ensure the grid is adequately prepared. Chicago’s exposure to both severe summer storms and dangerous winter cold puts it firmly in the middle tier of at-risk cities, serious, but not the worst.

San Juan, Puerto Rico: chronic fragility, not just storm damage

San Juan and Puerto Rico’s broader grid have become something of a shorthand in energy circles for what long-term underinvestment looks like. The island’s transmission and distribution system has struggled with reliability issues that predate any single hurricane, and its exposure to compound climate risk continues to draw academic attention. Researchers have specifically modeled the overlapping threats the island faces, since a grid weakened by one hazard often has little capacity left to absorb the next.

What sets San Juan apart from mainland cities is the sheer frequency of stacked hazards. Tropical cyclones, sea level rise, and heat waves rarely arrive one at a time there anymore, they layer on top of each other, and the grid’s slow recovery timelines have made blackouts feel less like emergencies and more like a recurring condition of daily life.

Miami, Florida: heavy investment against relentless exposure

Miami is an interesting case because its utility has actually spent significant money hardening the grid against hurricanes, undergrounding lines and reinforcing substations in flood-prone areas. Even so, the sheer geographic exposure to hurricanes, storm surge, and sea level rise keeps Miami in a high-risk category no amount of spending can fully erase. The city is a reminder that investment helps, but it cannot cancel out geography.

Extreme heat compounds the hurricane risk in ways that are easy to overlook. When storms knock out power in South Florida, the recovery period often unfolds under punishing heat and humidity, turning a grid failure into a public health emergency almost immediately. That layered risk keeps Miami near the top of most engineering assessments, even with real progress on infrastructure.

New Orleans, Louisiana: the city that came in dead last

No U.S. city illustrates grid fragility quite like New Orleans. When Hurricane Ida hit in 2021, the failure wasn’t partial or gradual, it was total. New Orleans faced catastrophic failures in both its transmission and distribution systems, beginning with the collapse of all eight transmission lines that bring power from a multistate grid into the city, a rare occurrence that left it completely disconnected from outside power.

The human cost was immediate and severe. The entire city lost power during the storm, and it took 10 days until restoration was nearly complete, during which time 10 people in the city died due to excessive heat. A 400 foot transmission tower, one that had survived Hurricane Katrina, simply gave way. Hurricane Ida knocked out all eight transmission lines feeding power into New Orleans, and its 150 mph winds also toppled a 400 foot tower that experts said would complicate power restoration efforts.

Investigators later found that the utility, Entergy, had been warned about exactly this kind of vulnerability. Weather data from the New Orleans International Airport recorded gusts up to 90 mph, below what the company itself says many of its towers and lines can withstand. A subsequent engineering review reached an even harsher conclusion. A white paper on Ida’s destruction released by McCullough Research, an energy consulting firm, suggested that Entergy and its regulators should work to replace aging grid equipment sooner rather than trying to squeeze extra years out of equipment until it fails completely.

To its credit, the utility has since committed real money to fixing the problem. Entergy New Orleans launched a $100 million accelerated resilience plan spanning two years, while Entergy Louisiana committed to a far larger program, $1.9 billion over five years. Even so, those upgrades are only more than halfway through the first phase, with the programs targeting infrastructure rated to withstand winds of 140 to 150 miles per hour, a threshold Ida exceeded in its worst moments. Until that work is finished, engineers who study grid resilience keep landing on the same conclusion. New Orleans built its reputation as the weakest link in the national grid the hard way, and it hasn’t fully shed that label yet.

The bigger picture for America’s aging grid

New Orleans may sit at the bottom of the list, but the gap between it and cities like Houston, Miami, or Detroit is narrower than most residents would like to believe. Every city on this list shares a version of the same underlying problem: infrastructure built for a climate that no longer exists, straining against demands it was never designed to handle. The lesson from New Orleans isn’t that its grid is uniquely doomed, it’s that deferred maintenance and underinvestment eventually come due, usually during the worst possible week of the year.