The ISO expects demand to peak at 47,847 megawatts. Last summer, unexpectedly high temperatures caused the demand to reach 50,270, a historic high on July 24, 2006.
Despite the increase in supply, ISO vice president of operations Jim Detmers said voluntary conservation will be needed to balance supply and demand.
"We will count on consumer to do their part to reduce electricity use on peak days when the California appetite for megawatts rises with the mercury," he said. "New power plants, transmission additions and demand response resources will help us keep pace with load growth, but margins will be tight on peak days, especially in Southern California."