As data centers and extreme weather events test the electrical grid, the possibility of a brownout in the D.C. region is unlikely, in part because of energy-saving programs that various utility companies offer, experts said.
Brownouts happen when a utility intentionally lowers the voltage on distribution power lines going into a home or business. When the voltage is reduced, lights appear to be a brownish color, though the impact is sometimes so minimal it goes unnoticed.
Heat waves and the increasing presence of data centers have “pushed demand to record levels,” said Bob Hobbs, Schad professor of environmental management at Johns Hopkins University.
“The last five years have been a big change,” Hobbs said. “We’ve seen, of course, an increasing frequency of heat waves. We’ve seen the data centers and crypto, which also consumes a lot of power.”
As the D.C. region sweltered under 100-degree temperatures earlier in July, regional grid operator 鈥� an estimated 168,158 megawatts between 5 p.m. and 6 p.m. on July 2, according to preliminary data. PJM edged out a previous peak record set Aug. 2, 2006.
However, there haven’t been any weather-related events on the PJM system that have led to brownouts, a spokesman told WTOP in an email.
Similarly, a Dominion Energy spokesman told WTOP that while it hasn’t been confirmed yet, “I suspect that we set multiple all-time peak load records” during the heat wave over the July Fourth weekend. A similar record was set during the extreme cold weather in late January; in a 24-hour period this winter, load demand increased 25%, the spokesman said.
Brownouts are generally deemed a last resort, Hobbs said, because if voltage drops too much, the quality of service deteriorates. It could mean a less bright light bulb, a toaster oven that’s less hot or a small rise in the household temperature, even if the air conditioning unit is operating at full capacity.
Some residents have signed up for energy saving programs, which help prevent brownouts. Pepco, for one, offers customers who enroll bill credits in exchange for the ability to adjust the air conditioning unit or heat pump during peak times.
Similar programs exist for factories and manufacturing facilities, Virginia Tech electrical engineering professor Saifur Rahman said. In exchange for the ability to temporarily shut down power, they get a lower rate.
“If you have significant shortages of capacity, the first thing a utility does is, their customers that it’s contracted with to interrupt them during shortage periods, in exchange for which they get a lower price, those get interrupted first,” Hobbs said.
While data centers require significant power, the arrangements are preplanned, Rahman said. So, when a company agrees to give a data center power, it has to arrange for extra power to be brought in through transmission lines or local generation.
During this month’s heat wave, the U.S. Department of Energy gave PJM the authority to direct utilities to move data centers to backup generation. However, the company didn’t need to take that step, it said.
PJM didn’t direct utilities to temporarily cut power in targeted areas, and doesn’t anticipate needing to do it as 100-degree temperatures return this week, a spokesman said.
When power is lost because of a storm, Hobbs said, the result is a blackout. But brownouts generally refer to “an imbalance of overall supply and demand because of heat increasing demand and at the same time decreasing supply.”
“It’s not like we’re going to be living with brownouts every day for a year or anything like that,” Hobbs said. “It’s going to be short in duration, but of course, at precisely the time that you really need the power for you, the air conditioning.”
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