SACRAMENTO, Calif. (KTXL) — California’s power grid operator asked residents to voluntarily conserve energy starting Wednesday afternoon. 

The Flex Alert was issued by the California Independent System’s Operator for Wednesday from 4 p.m. to 9 p.m. in anticipation of high temperatures. Wednesday is expected to have temperatures above 100 in Sacramento. 

According to CAL ISO, high temperatures are expected in much of California, which could lead to added stress on energy supplies. 

“Consumers are urged to conserve electricity, especially during the late afternoon and early evening, when the grid is most stressed due to higher demand and less solar energy,” Cal ISO said.

Before the Flex Alert begins, Cal ISO recommends pre-cooling homes to 72 degrees. It also advises residents to use major appliances such as washers, dryers and dishwashers before 4 p.m. 

Ovens and stoves should also be used to pre-cook and prepare meals prior to the Flex Alert. 

During the Flex Alert, residents are asked to set their thermostats to 78 degrees or higher. Those with health concerns are exempt. Residents should avoid using their major appliances and turn off lights that are not in use.