Travel 25 miles north of Philadelphia to find the region's first line of defense against the summer sizzle - a command post where technicians warily eye a nearly two-story-high electronic wall map and banks of computer monitors 24 hours a day, seven days a week.
The mission: Keep the megawatts flowing to 23 million people from New Jersey to Virginia - even during a heat wave.
The Valley Forge command post belongs to the PJM Interconnection LLC, an independent system operator that controls the region's power grid - 8,000 miles of transmission wires connected to 540 power plants. At the top of the wall map a red neon sign tracks the grid and shows how many megawatts are in use.
During July's heat wave, system emergencies, brownouts and rolling blackouts hit parts of the East Coast, as electric utilities and power companies struggled to balance the demand for energy with supply.
As an early spell of hot weather in May strained the region's power system again, the question at hand is: Will there be enough electricity to meet consumer demand this summer?
Electricity demand, fueled by a booming economy, is rising while power generation and transmission network capacity have remained relatively constant, forcing PJM to operate close to its reserve margins on occasion.
In fact, the North American Electric Reliability Council (NERC), an electric utility trade group, recently projected that peak demand this year will be 1.7 percent above 1999's level, and parts of the nation - including the Northeast and the Southwest - may not have enough electricity to meet consumer demand during the hottest days. In its monthly short-term energy outlook, the U.S. Energy Information Administration, a statistical agency of the U.S. Department of Energy, said shortages cannot be ruled out if there is a repeat of last summer's record heat.
Furthermore, a recent U.S. Energy Department report said the nation's electricity supply has become less reliable because of the open competition among utilities.
While areas such as New England, New York, California, Arizona, and New Mexico have been identified as most at risk for outages this summer, PJM, is also gearing up for a possibly hectic summer.
"We can't predict what this summer will be like," said Melissa Singleton Josef, a spokeswoman for PJM. "This summer will automatically be better, system-wise, because of what we learned last year."
Problems in 1999
