The call for conservation between 4 p.m. and 10 p.m. came as excessive-heat warnings expanded to all of Southern California and up into the Central Valley, and were predicted to spread into Northern California later in the week.
The initial Flex Alert was issued for Wednesday, Aug. 31. It was later extended to Thursday, Friday, then Saturday, Sunday, Monday, and now Tuesday.
Labor Day was expected to strain the state's power grid the most.
On Wednesday, Governor Gavin Newsom discussed the heat wave expected to impact California and the West Coast, lasting through Labor Day weekend until next Wednesday.
"We are anticipating this extreme heat to be a length in duration to the lengths that it hasn't been in sometime," said Newsom
He shared ways Californians can stay safe from extreme heat, the strain the extreme weather will place on the grid, and state actions to respond to the immediate emergency and accelerate the state's transition away from fossil fuels that worsen extreme heat.
Triple-digit temperatures or close to it expected across California through the weekend and into next week.
"I think if you go back five years there were some of those but they weren't quite as intense and they were a little bit further between, but now every week almost we're getting smacked in the face with some big new extreme weather event somewhere," said Meteorologist Alison Bridger of San Jose State University.
Bridger referring to not only the extreme heat, drought, and fire conditions here in California, but extremes elsewhere too.
"China has had extreme hot weather, unprecedented hot weather. India had a heat wave back in spring before the monsoon. Now the monsoon is causing mass devastation in Pakistan and we've had similar events in the United States this year," said Bridger.
Climate scientist and Stanford professor Noah Diffenbaugh says that going forward, more of these type of weather events are likely to happen due to climate change.
"We have clear evidence that the probability of unprecedented heat events is going up, and it will continue to go up in the future as we do get more global warming in the coming decades," said Diffenbaugh.
Diffenbaugh says in California extreme heat events are happening in late summer and early fall when warming is happening more rapidly.
As for this year, with hot temps already here, there is hope, but fear over another dry La Niña going into the New Year.
"I kind of had been hoping for a normal winter, and there's still a chance that we could get one, but when you throw La Nina on top of everything we're more likely to be like the last couple of years and that's frightening and depressing at the same time," says Bridger.
RELATED: Extreme heat dangers and safety tips - What you need to know
[Ads /]
What to do in a Flex Alert
During a Flex Alert, people are asked to reduce energy use between 4 p.m. and 9 p.m.
VIDEO: What is a Flex Alert?
VIDEO: What's a Flex Alert?
If things get bad, there's potential for rolling blackouts.
[Ads /]
During this heat wave, CAL ISO says it will be using available resources and tools to meet the heightened demand for electricity.
That includes cutting back on scheduled maintenance between noon to 6 p.m. starting Wednesday through Tuesday of next week to make sure all available generation and transmission lines are in service.
The CEO of CAL ISO released a video statement urging all residents to do our part.
"Like the extreme weather events we've seen throughout the summer, our best bet for getting through a challenge like this is when we all pitch in and do what we can," said Elliot Mainzer.
CAL ISO encourages people to raise their thermostat to 78 degrees, avoiding the use of large appliances and turning off unnecessary lights.
[Ads /]
Those with electric vehicles are asked to charge their cars prior to 4 p.m. when more solar energy is available.
The Associated Press contributed to this report.