CAISO October 2026: Battery revenues rose to $3.09/kW-month following early-month heatwave
CAISO October 2026: Battery revenues rose to $3.09/kW-month following early-month heatwave
Battery revenues in CAISO rose to $3.09/kW-month, up 52% from $2.03/kW-month in September and 3.6% above $2.99/kW-month in October 2025.
A heatwave in early October was responsible for most of the increase. The first eight days made up 49.5% of the month's revenue.
Southern California sat under National Weather Service extreme heat warnings until 8 October, following CAISO's Restricted Maintenance Operations from 5 to 8 October. Demand peaked at about 46 GW on 5 October, 98% of the CEC's 1-in-2 planning peak of 46.8GW, resulting in batteries earning $349/MW that day.
Standalone batteries earned $4.34/kW-month in October 2026, 40% above the index
Standalone batteries in CAISO could have earned $4.34/kW-month in October 2026, 40% above the ME BESS CAISO index. These backtests come from Modo Energy's virtual benchmarks, providing a view of near-perfect foresight asset-level performance in the California ISO.
About the simulations
| Setting | Value |
|---|---|
| Batteries simulated | 102 standalone CAISO batteries of 10MW or more |
| Capacity | 7,908MW across 36 owners |
| Price node | Each battery's price node |
| Markets | Day-ahead (IFM), real-time (FMM, RTD), regulation, spinning and non-spinning reserve |
| Round-trip efficiency | 88% |
| Cycling | Up to two cycles a day |
| Contracts | None |
| Foresight | Perfect foresight of prices within each operating day |
| Calibration | Revenue derated to 90% to account for typical availability issues and imperfect foresight |
Aypa Power topped the owner ranking with Cald, a 100MW, four-hour battery in Los Angeles County and Aypa's only battery in CAISO.
On 5 and 6 October, real-time daily TB4 price spreads at Cald's node averaged $2,293/MW-day, more than six times the $359/MW-day at the SP15 hub. Its four cheapest hours averaged $44/MWh, close to the hub's $37/MWh. But its four most expensive hours averaged $617/MWh against $126/MWh at the hub, with congestion making up 86% of that price.
Those two days made up 55% of Cald's simulated revenue. During the rest of the month, Cald earned $3.56/kW-month, compared with $3.37/kW-month for the average battery.
Read last month's report here.
Unlock the rest of the article to find out:
- What drove price spreads in each zone?
- How did individual assets perform this October?
- How did battery bidding change?
If you have any questions about our CAISO research, please reach out to ovais@modoenergy.com.
Real-time TB4 spreads rose 6.7% year-over-year while day-ahead rose 18%
Real-time daily TB4 spreads averaged $154/MW-day across CAISO's battery nodes in October, up 6.7% from $144/MW-day a year earlier. Day-ahead daily TB4 spreads rose 18% to $159/MW-day.
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