Sep 7, 2021 — Atlanta, GA

Brian Stone’s five-year study of heat waves in the US found that temperatures in cities like Atlanta, Detroit, and Phoenix are hotter than they used to be.

But what really surprised him, as an expert on urban environmental phenomenon, was learning that power outages concurrent with high temperatures have more than doubled since 2015.

That means that the number of major blackouts affecting 50,000 people or more has increased by more that 100%, he said, and they increase most rapidly in the summer.

Additionally, “In just the last five years, we discovered that the blackouts impacting more than a million people have lasted for an average of five days,” Stone said.

When the power is out, and the weather is hot, that’s a gravely threatening condition, he said. “A widespread blackout during an intense heatwave may be the deadliest climate-related event we can imagine,” he told the New York Times.

Usually, power outages happen due to big storms, like hurricanes, Stone said. “Those storms are coming through in the summer. The hurricane is threatening, but there’s also a lot of really hot weather and high temperatures that immediately follow the hurricane.”

Stone’s research simulated heatwave temperatures as well as those inside people’s houses to better understand the human risks of power outages. As a professor in the Georgia Tech School of City and Regional Planning, Stone teaches his students to prepare for intense heat, and how to protect local populations.

Stone’s colleague in the Georgia Tech School of Public Policy, Daniel Matisoff, thinks about resilience to heat and power supply in three levels: individual resilience, neighborhood resilience, and community resilience.

“At the individual level, maybe we just need more air conditioners, and affordable, renewable energy that is more reliable. At the neighborhood level, maybe we’re thinking about using new building technologies, or planting trees to keep the area cool. At the community level, we’re thinking about social services, like places people can go to cool down if they’re hot,” he said.

Matisoff’s research in green market transformation, especially around the built environment, centers around adoption and diffusion of innovative energy and environmental technologies.

“I think we’ve tried to ignore natural resilient systems and replace them with air conditioning or engineered systems,” he said, “but how this interacts with power outages is another story, because an air conditioner won’t work if you don’t have electricity.”

A better way to find resilience for this nightmare scenario is collaborative heat management, Matisoff said. “The idea is we take advantage of local knowledge, we match solutions with appropriate contexts and preferences, and get more citizen and stakeholder input – so that we’re not trying to impose engineered solutions.”

It turns out, Georgia Tech and institutes like it are a key part in that diffusion of information, he said. Pilot building projects like “The Living Building” share innovative technologies and building practices with local industries and communities.

If an organization like Georgia Tech is, “talking about skins of buildings that reflect heat or ways that allow the built environment to build resilience into the electricity system, solar power,” he said, “it demonstrates to the market that this technology is commercially viable.”

Practices like regularly retro commissioning campus buildings, and research into distributed energy generation and micro grids are just a few of the contributions Georgia Tech shares with the city of Atlanta and nationally, he said.

There’s a limit to what the built environment can do to protect people from extreme heat, said Tarek Rakha, Assistant Professor in the School of Architecture and the director of the High Performance Building Lab.

“People don’t know how to react to heat,” Rakha said. “When it gets too hot you need to be in some form of shade. There’s a minimum amount of clothing you should wear, and you need to have access to water. You need to be hydrated all the time. And after that, you’re in trouble.”

For example, Rakha said, sitting or sleeping on the roof of a structure that is exposed to the sky is much better than being indoors in a structure that encloses the heat and does not dissipate it using natural ventilation. It’s not intuitive for many city-dwellers to do that, he said.

As more people move to cities, they are more reliant on air conditioning, he said. But when cities face high heat, “it’s a risk of lives, a risk of infrastructure.”

“When we are talking about communities that are significantly affected by heat, we are talking about vulnerable populations such as the elderly or those without the means to air condition,” he said. The most vulnerable populations in cities often live in older buildings that have deteriorating roofs, falling facades, or windows that are broken. In many cases the people living in these inefficient structures cannot afford to cool them. 

But even without air conditioning, there are several other types of equipment used in buildings that city dwellers rely on, Rakha said. "Aside from contributing to the overall heat in the built environment, these machines may not be resistant or resilient in an extreme heat event," he said, "and that puts our lives at immediate risk."

The best defense against high heat is to plan ahead, he said. Rakha suggests cities invest in smart grids to keep the power on during a heat event. Specifically, "smart grids that work on demand response that are able to manage peak loads. Interaction with users should be related to how the energy is supplied," he said.

As for the buildings themselves, he suggests retrofitting roofs, adding more insulation, fixing windows, and adding renewable energy sources like solar power.