California warns residents of 'very possible' blackouts, declares energy emergency as heat wave strains the state's energy grid

• California's grid operator warns of "very possible" blackouts as the heat wave strains the state's power grid.
• The peak electricity demand in the state is forecast at more than 52,000 megawatts, an all-time high for the grid.

California's power grid manager alerted residents that blackouts were "very possible" Tuesday evening as the western US continues to experience a nearly week-long heat wave, straining the state's energy supply.

California's grid operator California ISO raised the energy emergency alert status to the highest possible level on Tuesday, urging residents to reduce their power use. The peak electricity demand in the state is forecast at more than 52,000 megawatts, an all-time high for the grid, according to a statement.

As of 6 p.m. local time, California ISO has not yet called for rotating power outages to protect the energy grid, which is the next step after declaring a stage 3 alert.

"If outages are initiated, consumers can expect to receive notifications from power providers on areas affected and time duration," the grid operator said in a statement.