Grid Stands Up to Heat Wave & Fires

California’s grid handled a heat wave that ended Aug. 17 without missing a beat as temperatures soared above the century mark in the coastal valleys of Southern California and above 90 degrees in inland valleys in the Bay Area beginning Aug. 13.

The Central Valley and Southern California desert areas also were scorching hot.

Heading into the heat wave last week, utilities appealed for conservation. The grid operator ordered generators and utilities to defer routine maintenance on power plants and transmission lines to keep all facilities in service.

High temperatures helped fuel wildfires up and down the state, including one known as the Warm Fire east of Lake Castaic in Southern California that forced two 500 kV transmissions lines out of service for about an hour on Aug. 16, according to Steven Greenlee, California Independent System Operator spokesperson.

The Cuesta Fire in San Luis Obispo County forced out a couple of 230 kV lines on Aug. 17 and 18, but did not impact grid reliability, said Greenlee. Lower temperatures since then have eased concerns.

Fires elsewhere came close to other lines, but not near enough to cause any threat or to interrupt service.

As temperatures rose, demand on the grid spiked Aug. 13 at 47,709 MW, up from 39,428 MW the day before. Peak demand hit 42,345 MW Aug. 14, 42,625 MW Aug. 15, 43,554 MW Aug. 16, and rose again on Aug. 17 to 44,346 MW.

The National Weather Service was predicting cooler temperatures Aug. 18 into the weekend. Weather forecasters predicted another heat wave next week, although milder than the one that began Aug. 13. —William J. Kelly