Grid-scale batteries in CAISO earned $1.88/kW-month in July 2026, down 19% from July 2025's $2.33/kW and 26% below June's $2.55/kW.

Day-ahead TB4 spreads widened from $3.26/kW-month to $3.34/kW-month year-over-year. But revenues reported in the ME BESS CAISO index declined due to recorded losses in the Real-Time FMM energy market.

Batteries, on aggregate, charged during periods of elevated evening prices. Evening prices spiked this July on high-load evenings when demand was met by natural gas.

Read last month's report here.

Key Takeaways

• Battery revenues fell 19% year-over-year to $1.88/kW-month, level with February 2026 as the lowest monthly figure since December 2025.
• Fifteen-minute market revenue turned negative, at -$0.25/kW-month. It is the only negative month in the index history.
• The evening real-time basis flipped. Five-minute prices settled $3.40/MWh above the day-ahead clear, against $9.16/MWh below it a year earlier.
• Day-ahead conditions improved. TB4 spreads widened to $3.34/kW-month and hours above $60/MWh tripled from 20 to 61.
• Average demand rose 10% and gas generation rose 29%, while daily solar volume held flat.
  
  TB4 is the spread between the four highest and four lowest hourly prices in a day. IFM is the Integrated Forward Market (day-ahead), FMM the Fifteen-Minute Market, and RTD Real-Time Dispatch (five-minute).
  
  If you have any questions about our CAISO research, please reach out to ovais@modoenergy.com.

CAISO Real-time TB4 spreads rose 42% as gas and imports meet high demand

Real-time TB4 spreads reached $4.19/kW-month across the CAISO footprint in July 2026, up 42% from $2.94/kW-month a year earlier. Day-ahead spreads rose 3%, from $3.26/kW-month to $3.34/kW-month.