Eastern US Power Grid Orders Cuts Amid System-Wide Emergency

PJM, a vast electric grid that stretches from Illinois to New Jersey, has declared a rare, system-wide emergency and is ordering some customers to curtail demand as a vast winter storm sends power use soaring. This is a rare event and PJM is taking necessary precautions to ensure the safety of the grid and its customers.

PJM Interconnection LLC, the grid operator, has declared a Stage 2 emergency. This requires customers who have agreed to curtail power during times of extreme need to do so. PJM has also appealed to people to conserve electricity as much as possible during the holiday weekend, from 4 a.m. Eastern on Saturday to 10 a.m. the next day, because of frigid conditions.

The last thing a grid manager can do to avoid a Stage 3 emergency is to plead directly to consumers. This has meant in the past that rolling blackouts are imminent or already in effect. Such widespread cutoffs would be devastating for as many as 65 million people relying on the grid for power just as an enormous winter storm batters swaths of US and Canada.

Demand for electricity soared more than 9 gigawatts above forecasts Friday evening — much faster and higher than anticipated. That’s the equivalent of about 9 million homes just popping up on the grid on a typical day.

PJM spokeswoman Susan Buehler said in an interview that the Stage 2 emergency will "certainly be enough" to avert rotating shutoffs. She said that the grid operator had not forecast how quickly temperatures would drop, but that millions of people turning on their heaters had created a sudden demand for electricity.

A Stage 2 emergency is very rare for PJM. The last time it declared an emergency of this kind was in March 2014 when a polar vortex caused problems for the system for months.

The grid operator said in an emailed statement that asking consumers to voluntarily cut usage is another measure to keep power flowing in extreme weather, something that was effective in California.

This week's storm has already knocked out power to hundreds of thousands of people in more than 25 states, from Maine to Texas. The Tennessee Valley Authority, which provides electricity to several states, has ordered rolling blackouts to cope with overwhelming demand.

Stage 2 emergencies require businesses enrolled in so-called demand response programs to curtail power use. As part of these programs, companies agree to cut consumption when called upon in exchange for payments. This helps to prevent blackouts and other power disruptions.