Grid-scale batteries in CAISO earned $2.77/kW-month in April 2026. That is below March's $3.70/kW (-25.1%), and the third sub-$3/kW month so far this year.

Temperatures held within a degree of last April. With weather neutral, price compression came from the supply side: a battery fleet over 16 GW absorbed midday surplus and discharged enough volume after sundown to cap evening peaks, displacing gas from the supply stack.

CAISO wind production rose 32%, hitting new records for peak production supported by the 3.5 GW SunZia wind site coming online in New Mexico.

Solar generation fell 6.5% year-over-year. The two forces squashed both ends of the price spread: the lower midday solar peak raised midday prices, while stronger overnight and evening winds held evening prices below last year's peaks.

​Read last month's report here.

TB4 spreads narrowed from $189/MW to $123/MW year-over-year

Daily average TB4s fell from $189/MW to $123/MW year-over-year. The strongest day of April 2026 was April 4 at $169/MW, which would have been a below-average day in April 2025. The weakest day, April 25, posted just $74/MW.