SAN FRANCISCO — The operator of California’s electric grid says up to 3.3 million homes may lose power as part of rolling outages to ease pressure on the state’s energy grid.

The California Independent System Operator says it will likely order utility companies to turn off power starting around 4 p.m. Monday as demand for electricity to cool homes soars during the hottest part of the day beyond the power available in the grid.

More shutoffs have been ordered because of an energy shortage caused by a heatwave engulfing the West Coast.

The head of the system says those affected can expect to lose power for about two hours.