PJM announced Thursday the program was a major success.
It said Wednesday's demand response effort helped save an estimated 5,949 megawatts of power across the entire Mid-Atlantic region - the largest amount of demand response the company has ever seen.
PJM executives said the demand response essentially acts like additional generating capacity across the system.
It said the 5,949 megawatts of conserved power roughly translated to the output of about five nuclear plants or generators.
"Generation performance and demand response played significant roles in balancing the supply and demand on the grid during unusual conditions this week," PJM executive vice president Andy Ott said in a statement.
Instead of spiking to 149,000 megawatts Wednesday, PJM recorded the peak demand for electricity for the day as 142,071 megawatts during the 3 p.m. hour.
"PJM continues to see the value and success of demand response participating in PJM markets," Ott said.
The strain on the system abated Thursday as a cold front began sweeping across the northeast.
PJM estimated Thursday's peak power would hit 130,481 megawatts, much lower than the levels recorded earlier this week.
Contact writer Jared Hunt at busin...@dailymail.com or 304-348-4836.