Charging Ahead: Modeling Batteries and the Future Grid at CAISO
Thomas Saito is a junior studying Energy Science and Engineering.
About CAISO
What does it take to keep the lights on in the fourth-largest economy in the world?
This summer, I’m getting a front-row seat as an intern with the Resource Assessment & Planning (RA&P) team at the California Independent System Operator (CAISO), the organization responsible for the economics, engineering, planning, and reliability for the majority of California’s electric grid. CAISO’s mission includes ensuring grid reliability, managing real-time power flows across high-voltage transmission lines, overseeing transmission planning, and operating the state’s wholesale power markets, often in coordination with California Energy Commission and the California Public Utilities Commission. In addition to its role as a balancing authority, CAISO is also responsible for operating the Western Energy Imbalance Market and serves as the Reliability Coordinator for much of the Western United States.
About my project
For my project this summer, I’m coalescing generator fleet information and writing scripts to optimize battery behavior for a long-term study, which aims to evaluate the operational characteristics of the fleet of the future. California’s electric grid has experienced tremendous growth in the amount of renewables, even making headlines this summer for their role in providing ⅔ of California’s energy in 2023. Although the headlines reaffirm the incredible progress California has achieved towards meeting its ambitious climate goals, behind the scenes, operators face real-time challenges of integrating renewable resources, particularly the sharp fluctuations in net loads, commonly referred to as the duck curve. The combination of continued electrification and build out of renewable resources, alongside the retirement of baseload and flexible generation make these operational challenges more severe. Batteries are already helping to meet demand during critical periods like the evening ramp and the morning load increase, and their importance will only grow. Due to the novelty of battery resources and their growing role in future energy fleets, there is significant room for improvement in how their behavior is represented in deterministic resource adequacy stack models, and this summer, I’m exploring new methods to better capture their behavior and value.
A typical day
Most of my team is remote, so I typically attend meetings virtually and do work at my desk in the morning. I’ll usually make myself lunch and whenever they’re hosted, attend the organized lunch-and-learn series where interns can learn about current employees and their role at the ISO. After lunch, I’ll check-in with my manager, and do more work. I’ve also gotten the opportunity to work in-person at CAISO, and this week the HR team arranged travel and events for all interns to be on-site together. I’ve also been making an effort to explore some of the restaurants and nature in and around Folsom. No filter needed here!
The learning journey
One of the speakers at the lunch-and-learn series described the learning curve for new employees at the ISO as a “learning mountain” and after sitting in some of these meetings, I’d have to agree with his characterization. Even though this wall of economic, political, and technical challenges may feel overwhelming at times, each day, I’m gaining a deeper understanding of the grid and even greater appreciation of the engineering complexity and effort that it takes to run an efficient and reliable electric grid. For some further reading, I highly recommend this 2024 Special Report on Battery Storage written by the DMM at the CAISO, and for some of the work my team publishes, I’ve included their annual 2025 summer loads assessment. Energy veterans always say it's such an interesting time to be in energy and from the conversations I’ve had with those at the ISO and data I’ve explored in my project, I think so too. Load is changing, supply is changing, and there’s always something new to investigate. What began as a “learning mountain” has turned into a rewarding climb, and I’m excited to keep ascending! Time to charge ahead! 🔋⚡
