With the expectations that peak demand for electricity this summer will be less than last summer’s record, PJM Interconnection, which manages the nation’s largest electricity grid spanning all or parts of 13 eastern states and the District of Columbia, said last week that power supplies in its region should be sufficient to meet consumers’ forecasted peak usage this summer.

“We expect no issues or concerns with the transmission system this summer,” said Michael J. Kormos, PJM senior vice president-Reliability Services. “The system and our members performed extremely well last summer during a period of challenging record demands, and we anticipate the same performance this summer.”

PJM’s forecasted 2007 summer peak usage is 136,961 MW. The operator said it expects to have 160,680 MW of firmly committed generating capacity available. This amount, along with another 3,600 MW of additional capacity that could be available in peak conditions, brings PJM’s reserve margin to 18.8% for committed capacity and 21.4% for total capacity. Both amounts exceed the required reserve margin of 15%. Reserve margin provides a “cushion” of generating capacity to meet unexpected high usage levels or equipment problems.

PJM’s new capacity construct, the Reliability Pricing Model (RPM), requires resources owners to firmly commit their generation to PJM for a full delivery year, which begins June 1. Previously, owners could decide on a daily basis to make their generation unavailable to PJM and to sell it elsewhere.

“RPM, which goes into effect June 1, is showing an immediate benefit,” Kormos added. “RPM’s requirement for firmly committed capacity better ensures that the system will meet peak demands.”

Last summer, extreme temperature and humidity across the entire PJM region drove customers’ use of electricity to a record peak of 144,644 MW. PJM noted that the extraordinary weather conditions were a once-in-35-years event.

PJM expects to have 3,103 MW of interruptible demand and load management programs this summer. Customers in these programs typically receive either a special rate or payments for stopping or reducing their use of electricity during peak load hours. Of this 3,103 MW, about 1,670 MW is expected to be under PJM’s control and interruptible for reliability reasons. The operator added that demand response also has been shown to reduce wholesale electricity spot market prices on peak electricity use days.

PJM said the reliability forecast assumes normal summer weather conditions. It is a standard “50-50” forecast, meaning there is a 50% chance that actual peak summer usage will be higher than the forecast, and a 50% chance that it will be lower.

PJM serves 51 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. The region’s transmission grid includes 6,038 substations and 56,250 miles of transmission lines.

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