A heat wave is expected to propel California electricity demand to a summer-like 44,828 Mw Monday, stretching the industry's ability to supply power to the grid.
In August, the peak load adjusted for load shedding was an estimated 45,208 Mw, the ISO said. The nominal peak before the ISO ordered load shedding by companies with interruptible supply contracts was 43,509 Mw in August, compared to the August 1999 peak of 43,925 Mw. Average daily peak loads this August were 39,856 Mw, a 12% increase over the August 1999 average daily peak.
In anticipation of continuing high demand the California Independent System Operator (ISO) has declared today a power watch day, the first in what is expected to be a series this week. The California ISO said it is strongly advising energy conservation as the state enters what weather forecasters predict will be a stretch of hot weather this week.
It ordered a "no touch" day, delaying power plant maintenance without ISO permission and asked for supplemental energy bids. On Sept. 13-14, the ISO declared power emergencies because of fires in northern and southern California which were affecting transmission lines and because some 4,000 Mw of generating capacity was off line.
Power plants totaling 3,964 Mw of electricity were off line Thursday due to mechanical failure or planned maintenance that could not be postponed, the ISO said.
Fire damage to a portion of the crucial California-Oregon Intertie was repaired Friday and the Diablo Canyon Unit 2 nuclear plant, which had been down, was back in operation Monday. Forecasted heat drove prices to a reported $200 Mw-hr.
The ISO reported that under-scheduling of both loads and generation continue to be a problem in the real time market. Loads had been decreasing but weather this week is expected to drive them back up again.
