Power Grid for 67 Million on Edge as Dire Cold Follows Storm (1)

A deep freeze is gripping the US in the wake of the worst storm so far this season, leaving the country’s biggest electric grid in emergency status and bracing for record wintertime demand.

PJM Interconnection LLC, which serves 67 million people from New Jersey to Chicago, issued a grid emergency for Tuesday and warned demand will exceed 147 gigawatts, an all-time high for winter. With another burst of frigid air expected Friday, electricity demand could remain above 140 gigawatts — roughly the output of 140 large nuclear reactors — through the end of the month.

Freezing temperatures now cover ...