The operator of the nation's largest electric grid says power supplies in its region should be sufficient to meet consumers' forecasted peak usage this summer. PJM Interconnection, which manages the electricity grid in all or parts of 13 states and the District of Columbia, expects peak demand for electricity this summer to be less than last summer's record.

"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 of electricity.

PJM expects to have 160,680 MW of firmly committed generating capacity available. This amount, along with another 3600 MW of additional capacity that could be available in peak conditions, brings PJM's reserve margin to 18.8 percent for committed capacity and 21.4 percent for total capacity. Both amounts exceed the required reserve margin of 15 percent. 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, 2007. 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 said. "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 world-record peak of 144,644 MW. The extraordinary weather conditions were a once-in-35-years event. In the PJM region, demand for electricity typically peaks in the summer because of high air conditioning use.

PJM expects to have 3103 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 3103 MW, about 1,70 MW is expected to be under PJM's control and interruptible for reliability reasons. Demand response also has been shown to reduce wholesale electricity spot market prices on peak electricity use days.

While PJM does not produce electricity, it manages the flow of it across the region and regularly plans for future use to make sure there is adequate supply.

The forecast assumes normal summer weather conditions. It is a standard "50-50" forecast, meaning there is a 50 percent chance that actual peak summer usage will be higher than the forecast, and a 50 percent chance that it will be lower.