Batteries in SPP South had the potential to earn $9.96/kW-month in June 2026, or roughly $119/kW-year annualized.

That was down from $12.20/kW-month in May 2026.

A battery operating with perfect foresight at the South Hub earned 78.6% of its revenue from Regulation. Day-ahead Regulation Up cleared at $12.35/MW, the RTO's highest-priced ancillary service.

RTO West continues to show the highest revenue potential, out-earning both the South and the North. That lead came almost entirely from Ancillary Services, where the West cleared higher in both Regulation Down and Spinning Reserves.

But that opportunity is shallow. SPP West is a thin market with low generation and load. Higher clearing prices reflect an early, lightly contested market rather than a deep revenue pool. Most operating batteries in SPP today sit in the South.

The remainder of this analysis breaks down what drove the revenue opportunity for battery storage in SPP in June 2026.

To learn about the price spreads at the launch of RTO West, read last month's May 2026 SPP benchmark report.

Regulation provided 80% of simulated revenues in June 2026

Ancillary Services provided 80% of modeled revenue in June, with Regulation alone making up 78% of the total.

Day-ahead Regulation Up prices cleared at an average of $12.35/MW in June, up 1.8% year-over-year - the highest-priced product in the stack. This service allows the system operator to make up for shortfalls in its dominant wind production. The high payments reflects of flexible gas, coal and hydro to cure short-term imbalances.

Day-ahead Spinning Reserve fell 22% to $3.8/MW, and day-ahead Ramp Up dropped 38.9%.

Read our guide to SPP’s Ancillary Services to learn more about how batteries participate in each market.

Day-Ahead TB4 spreads in SPP South fell to $4.7/kW

Day-ahead TB4 price spreads measure the value of cycling a battery between the four highest- and lowest-priced hours in a day.

Across June, a four-hour battery performing a single cycle a day with perfect foresight earned $4.75/kW-month in SPP South, down 11.2% year-over-year. SPP North totaled $4.42/kW-month, easing 1.8%, while SPP West totaled $3.66/kW-month.

Real-Time TB4s totaled $7.34/kW-month in the South, $6.47/kW-month in the North, and $9.19/kW-month in the new RTO West.

For batteries, Real-Time price fluctuations provide the highest arbitrage opportunity. But these spreads are the product of intermittent shortfalls in the RTO’s dominant wind generation. Prices spike for short five-minute intervals.

Operators capitalizing on these opportunities must forecast and time charges and discharges well, unlike solar-dominant grids, where the daily trough and peak are better defined.

A handful of days carried the month. June 17 cleared the top decile at both SPP South and SPP West. The daily TB4 spread reached $307/MW in the South and $216/MW in the West. SPP North's biggest day came later, on June 30. At $370/MW, it was the single widest daily TB4 spread of the month at any hub.

Rising wind pulled net load down 6% year-over-year

Wind generation averaged 14.3 GW, up 19% year-over-year. Coal fell 7%, while gas held roughly flat and solar rose 125% off its small base.

While demand continues to rise, wind has risen faster. Average SPP load climbed 3.5% year-over-year to 36.8 GW, and peak load reached 51.4 GW. But net load fell 6.1% to 21.8 GW. The added wind more than absorbed the year's load growth.

Excess wind absorbed the load growth and more, resulting in the grid dispatching fewer thermal generators than a year earlier, diminishing peak prices.

​June 17 offered the highest price spreads in both the South and West. It paired a wind-heavy, deep net-load trough with a sharp evening ramp. The steepest single net-load ramp of the month reached 4,915 MW hour-over-hour.