(Reuters) - The California Independent System Operator (ISO) on Wednesday told customers to be prepared to conserve energy as forecasts of extreme heat this week are set to raise power demand and could strain the grid.

The grid is stable right now, California ISO said, but it said events that linger for days can overtax generators and cause outages. The grid operator expects higher electricity demand on Wednesday and Thursday, with Thursday set to be the hottest day this week.

"If weather or grid conditions worsen, the ISO may issue a series of emergency notifications to access additional resources, and prepare market participants and the public for potential energy shortages," the ISO said.

It said it may also issue a Flex Alert, urging consumers to voluntarily reduce electricity consumption between 4 p.m. and 9 p.m. on certain days.

(Reporting by Anushree Mukherjee in Bengaluru; Editing by Leslie Adler)