 San Francisco-based power provider PGE Corp said on Friday it has started rotating power outages at the direction of Californias grid operator, impacting about 200,000 to 250,000 customers at a time, given the strain on the power grid during the statewide heatwave. PGE said its outages, directed by the California Independent System Operator, are expected to impact up to 250,000 customers at a time in rotations of one hour each. PGE will not be able to inform customers in advance of the shut-offs that could occur anywhere within the companys service area, the statement said. 