Last holiday season, we wrote about the challenges of the darker, colder part of the year for the CAISO battery fleet. In ‘‘Tis (Not) the Season for Batteries’, written in December of 2023, we explored the batteries’ tendency to miss out on both the lowest prices of the day for charging and the highest prices of the day for discharging in both Q1 and Q4. The growth of dispatch this year is clear; peak dispatch this December has grown by 1.7 GW on average while the typical morning is seeing around 0.9 GW more dispatch. With lower day-ahead and real-time energy prices this year compared to the last couple of years, batteries attempting to capture arbitrage already have less opportunity in 2024. In this report, we’ll investigate how the battery fleet is faring this winter so far and if it’s been able to improve strategy to better capture the available arbitrage opportunities.

Figure 1 | CAISO Battery Generation Year-on-Year