VALLEY FORGE, Pa., Jan. 9 (UPI) -- A call to conserve energy expired for U.S. consumers digging out after a severe winter blast strained the region's energy grid, a utility company said.
The Weather Channel forecast a steady warming trend beginning Thursday. That follows an arctic blast brought on by a weather phenomenon known as a polar vortex, which pushed temperatures well below the freezing point in U.S. states east of the Mississippi River.
PJM Interconnection, a company operating the electric grid for more than a dozen Midwest and mid-Atlantic states, lifted a call for conservation Wednesday as the cold spell began to moderate.
The company, which services more than 61 million people, said its grid was strained by the intense cold weather. Several natural gas-fired plants reported issues, though PJM said that represented a "relatively small percentage" of energy problems blamed on the extreme cold.
The company said it broke a record for electricity use twice Tuesday, with a morning peak of 138,000 megawatts and an evening peak of 141,312 MW. The previous record of 136,675 MW was set in 2007.
Early this week, PJM called on its consumers to reduce electricity use because of the cold snap. Conservation calls were made to avoid widespread power outages.
Chicago, which reported temperatures as low as minus 16 Fahrenheit Monday, can expect mostly cloudy skies Thursday with a high of 27 degrees.