Summer demand on the regional power grid is down 2 to 3 percent, according to PJM Interconnection, which manages electricity transmission in Pennsylvania and a dozen other states.
That’s likely due to the economic slowdown during the coronavirus pandemic: When shutdowns took effect in March and April, the grid saw a 10 percent drop in demand. And though people are now cranking the AC at home, many over-air-conditioned offices and other spaces are shuttered.
Still, utility companies are in overdrive to keep the electricity flowing, as thunderstorms and hot weather continue to stress the grid.
Hollie Geitner, a spokesperson for Duquesne Light, said the utility has seen about 27,000 customers lose power since temperatures began to climb July 3. She notes that some of those outages were caused by non-heat related issues, such as a car accident. But heat does play a role in outages: about 4,000 East End customers lost power earlier this week when soaring temperatures caused a cable to fail. Duquesne announced this week it will increase its staff to have more crews ready to respond to reported outages.
While thunderstorms and high temperatures are out of a utility’s control, companies like Duquesne Light take precautionary steps to prevent outages in the summer, like managing vegetation around a powerline.
“The heat can cause [power lines] to expand and sag,” Geitner said. When that happens, lines can droop down onto trees and other vegetation causing the lines to short circuit. So utilities send out crews to manage how vegetation is growing below or near a powerline.
It’s easier to move electricity in colder temperatures. The higher the temperature, the lower the amount of electricity a transmission line can carry. On top of that, customers are using the most electricity of the year during the hottest months.
“The good news is, when we design the system we plan for the very high usage on very hot days,” said Mike Bryson, senior vice president of operations at PJM Interconnection. His company manages where electricity goes, like air traffic control for kilovolts.
Duquesne Light’s Geitner says her company heavily relies on its customers to inform them when there is an outage. “I think some folks believe there’s this magic board where we’d be able to see when there’s an outage somewhere. That’s not how it works,” she said.
Historically, pole-mounted transformers haven’t provided data to predict outages due to overloading conditions. Newer smart meters do transmit that data to Duquesne Light, and a spokesperson said they are beginning to use it to predict overloading conditions on their distribution lines and transformers.
For larger substation transformers, real-time data is provided to DLC’s Operations Center and to companies like PJM Interconnection. In these cases when thermal ratings get too hot, companies can manually switch off equipment – causing a temporary outage – to prevent the transformer from permanent damage and, in some cases, exploding.
While some outages are unavoidable, there are things customers can do to help keep the grid from being overloaded in the summer, according to Geitner. Energy efficient devices are key, but she said people should consider turning up their thermostat a few degrees on the warmest days. The U.S. Department of Energy suggests setting a thermostat at 78 degrees when the house needs cooling, and higher when no one is home.