The California Independent System Operator called on voluntary interruptible load customers to reduce electrical usage by 1,000 Mw Wednesday, citing higher than expected demand and fires burning near transmission lines in southern California that have limited ability to move power.
Some 3,600 Mw of generating capacity is out of service for maintenance, "but it's the fires that are really hurting us," said spokesman Patrick Dorinson. "It's also very humid."
The ISO declared a Stage 2 electrical emergency, after a Stage 1 alert earlier in the day failed to reduce demand enough. The ISO was predicting a peak load of 41,561 Mw Wednesday. At 2:40 p.m. PST, loads had reached 40,456 Mw.
Stage 1 of the state's electrical emergency plan is called when reserves drop below 7%. If conservation measures don't lower demand for power, the ISO initiates a Stage 2 emergency, signifying reserves have dropped below 5%. On Tuesday, the ISO called a Stage 1 alert, as electricity consumption peaked at 39,908 Mw. It blamed high temperatures and humidity for the late afternoon surge in power usage.
California has grappled all summer with the effect of high demand coupled with not enough supply. CEO Terry Winter noted in testimony Monday that he and his staff must wage a near-daily battle just to keep the lights on in California because of market uncertainty.