Grid-scale batteries in CAISO earned $2.55/kW-month in June 2026.

That is down 4.6% from May's $2.67/kW and $0.52/kW below June 2025's $3.07/kW, a 16.9% year-over-year decline.

Revenues continue to hold around $2.5-2.7/kW for the third consecutive month.

Average daily highs reached 82.3°F against 83.0°F a year earlier, and average lows held at 55.4°F versus 55.3°F. With temperatures flat, the compression came from the supply side.

Wind generation rose by 31.5% year-over-year as the New Mexico-based SunZia continues to dampen prices.

Greenhouse Gas (GHG) price adders have begun printing non-zero prices for the first time since their launch in 2013.

The shift in greenhouse gas adders is a consequence of market enhancements introduced in May 2026 alongside CAISO’s Extended Day-Ahead Market (EDAM).

Prices during out-of-solar hours are expected to increase through this GHG component, as fossil fuel imports from the WECC rise. Batteries wil to benefit from higher peak discharge prices.

Within the Ancillary Services, Regulation Down prices fell from $5.36/MWh to $3.07/MWh, a 42.7% drop.

Read last month’s report here.

Edit (July 15th): An inaccuracy in the paragraph above attributed CAISO’s new GHG methodology to increases in market prices. This have since been amended for clarity.

CAISO TB4 price spreads compressed 14% year-over-year

Daily average Top-Bottom four-hour (TB4) price spreads fell from $135/MW to $116/MW year-over-year.

The strongest day of June 2026 was June 21 at $159/MW. The weakest day, June 24, posted just $64/MW.

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