The high temperatures had more people using their air conditioners, which increased the risk of the power grid being overloaded.
The California Independent System Operator reported the power grid hit an all-time record demand of more than 52,000 megawatts.
More demand could have prompted rotating power outages for some Californians.
The threat was so serious the state's office of emergency services sent out an emergency push alert, similar to ones sent for Amber Alerts.
In part, it said "Conserve energy now to protect public health and safety. Extreme heat is straining the state energy grid."
With triple-digit temperatures forecast in the Valley for the next several days, PG&E equipment could be pushed to its limit again.
Thousands of people in Clovis spent hours without electricity on Tuesday due to the extreme heat.
PG&E said it had to cut off some customers because equipment was close to failing.
"It's like driving your car 100 MPH down the freeway without stopping, eventually if you keep running at that speed, the tires will wear down more quickly," said Jeff Smith, spokesman for PG&E.
In the case power does need to be shut off by PG&E in an emergency situation, there will not be advance notice. The utility says customers should prepare for an outage -- most likely to happen later in the day.
"When people are coming home from work or school and may not have had their air conditioner running all day and they turn that on, that can be very taxing for the system," said Smith.