​Grid-scale battery revenues in the National Electricity Market (NEM) rose 12% month-on-month to $49k/MW/year in September 2026. This was the highest monthly level since April, but remains below the 12-month average and 41% lower than September last year.

NEM energy prices fell across the board, but fastest in the middle of the day, creating the opportunity for cheaper charging. Rising spring solar output and lower demand pushed midday prices below zero across states. Negative price intervals doubled in South Australia and Victoria to 30% and 24% of periods respectively.

Standard daily spreads drove revenues, which widened in every state except Victoria. No interval cleared above $500/MWh, and FCAS offered little support, with energy arbitrage making up 98% of revenue.

​This article reviews grid-scale battery revenues for September 2026, including energy and FCAS contributions, state-level outcomes, and asset-level performance. Find August’s NEM BESS revenue report here.

​Executive summary

• NEM-wide battery revenues rose 12% in September to $49k/MW/year, the highest since April 2026.
• South Australia saw the largest increase, but remained behind other states. New South Wales led all states at $56k/MW/year, overtaking Queensland.
• Spring conditions brought negative prices, which comprised 20% of price intervals across the NEM - up from 9% in August.
• Most batteries didn’t capture the biggest price spread of the month in New South Wales, Victoria and Queensland. Prices peaked in the early hours of the morning on the 24th of September.

​Revenues increased in all states and South Australia caught up

​September's increase came from energy arbitrage with NEM-wide energy revenue rising 12% to $48k/MW/year. The gap between the strongest and weakest states reduced to $17k/MW/year.