Demand response saves PJM’s bacon in sizzling fall heat

Feeling the heat from unusually hot weather, which this week created two of the highest electricity use days of the year in the 13-state region served by PJM Interconnection, PJM said Sept. 12 that demand response has been a big help.

Demand response is a voluntary reduction by a consumer in power use, which has played a vital role in keeping the power grid stable and air conditioners running, PJM noted.

Although September typically brings lower temperatures and lower demand for electricity, soaring temperatures in the last few days pushed electricity use to record levels for the month. Demand for electricity on Sept. 10 and Sept. 11 was higher than any day this summer except July 18.

Consumer use of electricity on Sept. 10 reached a record-setting 144,370 MW. Electricity use was headed even higher on Sept. 11 until PJM called for demand response. An estimated 5,949 MW of demand response resources (the largest amount of demand response PJM has ever received) were called on Sept. 11, comparable to five nuclear plants or generators. Demand response resources act like generation resources on the system.

“Generation performance and demand response played significant roles in balancing the supply and demand on the grid during unusual conditions this week,” said Andy Ott, PJM executive vice president – Markets. “PJM continues to see the value and success of demand response participating in PJM markets.”

The peak demand for electricity on Sept. 11 was 142,071 MW. By comparison, the peak demand for this summer on July 18 was 157,509 MW. Last year, the highest demand for electricity in September was 129,959 MW.

The extreme heat on Sept. 10, combined with local equipment problems, created localized emergency conditions in Indiana, Michigan, Ohio and Pennsylvania. PJM was forced to direct local utilities in those areas to immediately and temporarily reduce demand by small amounts to avoid the possibility of an uncontrolled blackout over a larger area that would have affected many more people. Of the 144,370 MW being served on Sept. 10, an estimated 150 MW were cut back to keep the grid stable.

PJM ensures the reliability of the high-voltage electric power system serving 61 million people in all or parts of Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and the District of Columbia.

About Barry Cassell 20414 Articles
Barry Cassell is Chief Analyst for GenerationHub covering coal and emission controls issues, projects and policy. He has covered the coal and power generation industry for more than 24 years, beginning in November 2011 at GenerationHub and prior to that as editor of SNL Energy’s Coal Report. He was formerly with Coal Outlook for 15 years as the publication’s editor and contributing writer, and prior to that he was editor of Coal & Synfuels Technology and associate editor of The Energy Report. He has a bachelor’s degree from Central Michigan University.