Heat forecasted for much of the western United States
FOLSOM, Calif. – The California Independent System Operator (ISO) is issuing this heat bulletin in anticipation of persistent above-normal temperatures and increased electricity demand next week in much of California and the West.
The above-normal temperatures and increased electrical demand are expected across California and the West over the Labor Day holiday weekend, intensifying through next week.
Temperatures in California are forecasted to be 6 to 12 degrees warmer than normal on Wednesday, Sept. 4 and Thursday, Sept. 5. The hottest days across the West are forecasted to be Sept. 4 through Sept. 6, with the warmest temperatures predicted for California, the Pacific Northwest and the Desert Southwest.
California ISO forecasters are carefully watching the middle to latter part of next week as the demand for electricity is expected to increase on those days due to high temperatures and air conditioning use.
The ISO has issued Restricted Maintenance Operations (RMO) for Wednesday, Sept. 4, through Friday, Sept. 6 from noon to 10 p.m. each day, due to high loads and temperatures across the state. During the RMO, market participants are cautioned to avoid scheduled maintenance to ensure all available generation and transmission lines are in service.
At this time, the grid is stable and we continue to monitor conditions carefully. While no supply shortfalls are anticipated, it is important to emphasize that extreme heat that lingers for many consecutive days can overtax generators running at high outputs for long periods, increasing the risk of outages and reduced generation. Wildfires can also pose a threat to generators and transmission lines. And the hotter weather, since it is also expected to affect other Western states, could limit the potential for importing energy.
The ISO will provide updates as necessary. If weather or grid conditions worsen, the ISO could issue a series of emergency notifications to access additional resources and prepare market participants and the public for potential energy shortages.
The ISO could also issue a Flex Alert encouraging consumers to voluntarily reduce electricity use from 4 p.m. to 9 p.m. on certain days. Flex Alerts are typically issued for the subsequent day based on day-ahead market outcomes. Learn more about conserving energy or sign up for text notifications at www.FlexAlert.org.
To stay current with forecasted supply and demand conditions and monitor grid status, please visit the ISO’s Today’s Outlook, download the free ISO Today mobile app, and follow us on Twitter/X at @California_ISO.
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California ISO | 250 Outcropping Way | Folsom, CA 95630 | www.caiso.com
The California Independent System Operator (ISO) is a nonprofit public benefit corporation dedicated, with its partners, to continuous improvement and secure operation of a reliable grid operated for the benefit of consumers.
It provides comprehensive grid planning, open and nondiscriminatory access to one of the largest networks of high-voltage transmission power lines in the world, and operates a $9 billion competitive electricity market. Recognizing the importance of the global climate challenge, the ISO is at the forefront of integrating renewable power and advanced technologies that will help provide a sustainable energy future efficiently and cleanly.
The Western Energy Imbalance Market (WEIM) is a real-time wholesale energy trading market that enables participants anywhere in the West to buy and sell energy when needed. The Western Energy Markets Governing Body is the governing authority designed by regional stakeholders and has shared authority with the ISO Board of Governors to resolve rules specific to participation in the WEIM.