 Bloomberg -- California utilities are carrying out rolling blackouts across the state for the first time since the 2001 U.S. energy crisis as a prolonged and extreme heat wave threatens to blanket much of the state through the middle of next week.The California Independent System Operator, which oversees the state grid, declared a Stage 3 emergency late Friday, initiating the outages with demand soaring from people blasting fans and air conditioners to keep cool. Temperatures were forecast to reach 112 degrees Fahrenheit 44 Celsius Friday in the San Joaquin Valley. Los Angeles was set to reach 96.The grid operator didnt immediately say how many homes and businesses may be affected by rotating outages but said the outages will occur throughout the state. Sempra Energys San Diego Gas Electric utility said 1-hour rotating shutoffs will be widespread across its territory in San Diego and southern Orange counties.The intense heat is hitting at an especially vulnerable time for the region with the pandemic forcing people to remain at home. Its the first time the state has declared a Stage 3 emergency since electricity shortages plunged hundreds of thousands in the region into darkness, forced Californias largest electric utility into bankruptcy and sent power prices surging to record levels in 2000 and 2001.The California ISO is working closely with California utilities and neighboring power systems to manage strain on the grid and to restore the power grid to full capacity, the agency said in a statement late Friday.California is joining regions around the world that have been grappling with extreme weather brought on by climate change in recent months. What was forecast as one of the worst heat waves in more than a century gripped parts of Europe in August. The eastern U.S. is just emerging from July temperatures that were expected to topple daily records in Manhattan and Boston dating to the 19th century.Fire CutoffsThe rolling outages in California also come less than a year after utilities in the region deliberately cut off power to millions of customers in an effort to prevent their power lines from igniting wildfires amid unusually strong winds -- another consequence of increasingly extreme weather.The state wont see a respite from the high temperatures until later next week as the National Weather Service forecast a long-duration heat wave starting this weekend. The weather agency posted excessive heat warnings for much of California for Friday through Wednesday.Further complicating matters, cloud cover from the remnants of tropical storm Elida is expected to crimp output from the states solar generators, leading to tighter supplies, the grid operator said in a statement Friday.Electricity prices have already hit two-year highs as weather forecasters called for extreme temperatures. Spot power prices surged past 1,000 a megawatt-hour across California on Friday evening. Natural gas prices in Southern California more than doubled on the increased need for the fuel for power production, according to report from BloombergNEF.Updates with scope of outages in third paragraphFor more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.2020 Bloomberg L.P. 