NERC: Reliable Electricity This Summer, Barring Extreme Weather

Electricity capacity is expected to be able to ensure reliable electric service throughout North America this summer, under normal summer weather conditions, according to Rick Sergel, president and CEO of the North American Electric Reliability Corporation (NERC). However, widespread and sustained hot and humid weather could threaten that reliability. NERC will release this and other conclusions in its 2007 Summer Assessment.

"The numbers tell us we will be OK, but the weather has been challenging in recent years. If areas of North America experience extended periods of extreme weather this summer, utilities may need to implement emergency procedures to reduce customer demand," said Rick Sergel, president and CEO of NERC.

In summer 2006, when extreme weather was experienced across much of North America, some utilities issued emergency alerts and public appeals, implemented voltage reductions, and exercised contracts with customers that allowed them to interrupt electricity supply in return for lower rates. All these actions helped keep supply and demand in balance and maintained the reliability of the bulk power system.

Extreme weather can impact the electricity grid in numerous ways. Higher demand for electricity, mainly from air-conditioning, stresses the electricity supply and delivery system. Generating units cannot be cooled as easily so their output has to be reduced to maintain appropriate operating temperatures. The amount of electricity flowing over transmission lines must be limited during extreme heat to prevent excessive line sagging and damage.

Several issues highlighted in NERC's Long-term Reliability Assessment issued in October 2006 are being addressed. The amount of demand represented by customer Interruptible Demand and Direct Control Load Management programs increased since last year by more than 10 percent in Florida, 13 percent in other parts of the southeastern United States, and almost 20 percent in the western United States and Canada. Many regions are studying the interdependence of fuel delivery and reliability, and improving coordination between fuel suppliers and generators.

For more information, see the NERC Web site.