Navigating the Summer Heatwaves: How CAISO Ensured Grid Reliability
Strategic Reliability Reserve Program units were instructed to start but were not needed.
The California Independent System Operator (CAISO) faced significant challenges during the July and September 2024 heatwaves. With soaring temperatures across California and the Western United States, electricity demand surged, testing the resilience of the grid. Leveraging the Strategic Reliability Reserve (SRR) program and demand response initiatives, CAISO effectively maintained reliability without triggering Flex Alerts or Energy Emergency Alerts (EEAs). Here’s an in-depth look at how CAISO managed these critical periods.
Strategic Reliability Reserve Program: A Critical Asset
CAISO’s Strategic Reliability Reserve Program was pivotal in ensuring the grid’s stability during both heatwaves. The program includes Long-Start Strategic Reserve Resources (LS-SRR), which are designed to provide additional supply during periods of heightened demand and reliability risk. Below is a ChatGPT breakdown of its deployment during the July and September events:
The source documents are - See section “11 Strategic Reliability Reserves and Non-Market Demand Response” here - https://www.caiso.com/documents/summer-market-performance-report-september-2024.pdf and here - https://www.caiso.com/documents/summer-market-performance-report-july-2024.pdf
July 10-11: Proactive Preparation
Forecasted Challenges:
CAISO anticipated heightened electricity demands across California and the broader Western region due to a developing heatwave.
Risks included potential overtaxing of generators operating at high outputs for prolonged periods, active wildfires threatening grid infrastructure, and limited energy imports due to widespread heat.
Proactive Measures:
LS-SRR units were instructed to start and remain on standby at minimum operating levels starting July 11.
Outcome:
As grid conditions improved during the day, LS-SRR resources were not required to dispatch beyond minimum levels. The fleet was shut down by the end of July 11 as temperatures and demand subsided.
September 5-6: Preparing for Peak Demand
Forecasted Challenges:
CAISO projected significant heat and elevated electricity demands across California and the broader Western region.
Risks included overtaxing generators running at high outputs for extended periods and limited access to imported energy due to regional heatwaves.
Proactive Measures:
On September 5, LS-SRR units were started and maintained at minimum operating levels to ensure readiness.
By late afternoon, CAISO instructed these resources to ramp to dispatchable minimum operating levels (DPmin) to prepare for evening peak and net peak periods.
Outcome:
Despite high system demands, LS-SRR units were not required to dispatch above DPmin levels as grid conditions improved closer to peak hours. CAISO shut down the LS-SRR fleet after September 6, as forecasts indicated subsiding temperatures and demand.
September 9: A Second Wave of Caution
Renewed Risks:
Persisting high temperatures and potential strain on generators prompted CAISO to activate three LS-SRR units on standby at minimum operating levels.
Outcome:
Improved grid projections eliminated the need for dispatch beyond minimum levels, and the resources were deactivated after September 9.
Demand Response Programs: A Supporting Role
CAISO’s collaboration with the California Energy Commission (CEC) and the California Public Utilities Commission (CPUC) was instrumental in managing demand during both heatwaves. Two key programs provided additional support:
Demand Side Grid Support (DSGS):
Trigger:
DSGS Option 3 was activated when CAISO’s day-ahead DLAP prices exceeded $200/MWh.
Impact:
While specific load reductions are yet to be assessed, DSGS played a vital role in mitigating demand peaks without requiring broader emergency measures.
Emergency Load Reduction Program (ELRP):
July:
DSGS and ELRP subgroups were triggered when the ISO issued an EEA Watch on July 24, providing additional support during peak demand.
September:
No Flex Alerts, EEA Watches, or other EEA levels were called during the September heatwave, so most ELRP subgroups were not triggered.
Future Evaluation:
CAISO plans to coordinate with the CEC and CPUC later this year to analyze the actual load reduction impacts of both DSGS and ELRP programs.
Challenges Faced
Environmental and Grid Stressors:
Prolonged heat across the Western U.S. strained generation resources and limited energy imports.
Wildfires posed additional risks to grid infrastructure during July, although these were not a direct factor in September.
Balancing Precaution and Cost:
The LS-SRR fleet’s activation ensured readiness, but careful planning avoided unnecessary dispatch, reducing operational costs.
Key Takeaways and Future Directions
Strategic Reliability Reserve Program Effectiveness:
The SRR program demonstrated its value in providing a reliable safety net without requiring full-scale deployment. Its flexibility allows CAISO to respond adaptively to evolving grid conditions.
Demand Response as a Crucial Tool:
DSGS and ELRP are increasingly integral to grid stability, especially during extreme weather events. Future evaluations will refine these programs to maximize their efficacy.
Proactive and Measured Approach:
CAISO’s decision to activate LS-SRR units at DPmin and its ability to avoid triggering Flex Alerts or EEA levels highlight the effectiveness of a cautious yet efficient strategy.
Collaboration Across Agencies:
Coordination with the CEC and CPUC underscores the importance of inter-agency efforts in managing California’s energy system.
Looking Ahead
As extreme weather events become more frequent due to climate change, CAISO’s ability to leverage reserves and demand response programs will be critical. Continued investments in flexible resources, enhanced forecasting, and robust demand-side management strategies will position California’s grid to handle future challenges.
The July and September heatwaves underscored the resilience of California’s energy system, thanks to proactive planning and innovative programs. As CAISO works with its partners to analyze and improve its strategies, these lessons will serve as a blueprint for managing future grid reliability challenges.
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