PJM Interconnection, the electricity grid operator for more than 61 million people in 13 states and the District of Columbia, experienced one of its biggest weather challenges during the month of January.

In its nearly 87-year history, this January's prolonged cold was record-breaking. Eight of the 10 highest winter demands for electricity ever recorded in the PJM region occurred last month as the extraordinary arctic cold gripped a large part of the U.S. and all of PJM for extended periods.

PJM's new all-time winter peak of 141,312 MW was recorded the evening of Jan. 7. Temperatures broke a record for cold that day in several locations in the PJM region. 

PJM employed a number of emergency procedures at various times during the month, including calling on demand response resources – businesses and industries that are paid for cutting back their use of electricity. They currently are not required to act in the winter months, but many demand resources did so.

With electricity supplies tight, PJM also issued appeals to the public for conservation on several occasions to help reduce high electricity demand.

"PJM again thanks consumers for responding to our requests to conserve electricity," said PJM President and CEO Terry Boston. "January was a challenging month, and the public response to our calls to conserve helped us manage the impact of the extremely cold weather across the entire PJM footprint.

"We also appreciate the performance of our members throughout the month of extended cold. Their cooperation and teamwork helped the region get through the challenging conditions without interruptions."

Among the challenges for PJM and its members in maintaining grid reliability during the month were unplanned generator shutdowns from the cold and the stress of extended run times, natural gas curtailments and fuel-oil delivery problems. All conventional forms of generation, including gas, coal and nuclear plants, were challenged by the extreme conditions. Because the frigid weather also affected neighboring grid areas, the availability of imported power to help meet demand and increase reserves was frequently limited.

These challenges came against the backdrop of extraordinary winter demand conditions in which usage for much of January was significantly higher than normal levels for the month – with many days 15,000 to 20,000 megawatts above normal. The additional demand is about as much power as would be used by the greater Washington and Baltimore subregion.

Because consumers used so much more electricity during the cold temperatures, their bills are likely to be higher than normal. Cold weather also pushed up wholesale power prices; however, the overall impact to consumers from higher wholesale prices should have little immediate effect on most residential bills.