Batteries in SPP South had the potential to earn $14.2/kW-month in August 2026, or roughly $170/kW-year annualized. That was 46% above July's $9.7/kW-month.

August was the first month energy arbitrage overtook ancillary services as the dominant part of the potential SPP battery revenue stack. Not because ancillary pricing weakened, but because day-ahead spreads at the South Hub more than doubled compared to August 2025.

Optimal revenues consisted of 53% energy arbitrage and 47% ancillary services. This is much higher than 23% from energy a month earlier. Regulation is still the single largest product, but its dominance eased last month.

Continue reading to learn why energy arbitrage revenues grew in August.

To see how batteries performed last month, read the July 2026 SPP benchmark report.

If you have any questions about our SPP research, please reach out to ovais@modoenergy.com.

​High wind and load widened TB4 spreads at both SPP East hubs

Day-ahead TB4 spreads reached $10.1/kW-month at the South Hub and $8.2/kW-month at the North Hub in August.

The South hub more than doubled year-over-year, up 105%, and the North widened 61%. SPP West cleared $7.9/kW-month.