Batteries Beat Gas at Australia's Evening Peak

For the first time in any quarter, grid-scale batteries supplied more of Australia’s National Electricity Market (NEM) evening peak than gas-fired generation, according to the Australian Energy Market Operator’s Quarterly Energy Dynamics report for Q3 2026. Batteries provided 8.0% of total generation during the evening peak (4pm to 9pm), ahead of gas on 5.1%.

The shift reflects how much more work batteries are doing across the day. The report says energy shifted by grid-scale batteries more than tripled year on year: they charged an average of 13.4 gigawatt-hours a day during daylight hours (10am to 4pm) and discharged 10.9 GWh into the evening peak, up from 3.7 GWh and 3.2 GWh respectively in Q3 2025. Battery charging or discharging set the wholesale price in almost half — 48% — of dispatch intervals, up from 18% a year earlier.

In brief

Grid-scale batteries supplied more of Australia’s National Electricity Market evening peak than gas for the first time in any quarter: 8.0% against 5.1%.
Batteries charged 13.4 GWh a day in daylight and discharged 10.9 GWh into the evening peak, set prices in 48% of dispatch intervals, and the fleet passed 10 GW/23 GWh.
Renewables hit a record Q3 share of 44.3% and wholesale prices fell 27% year on year, though wind and solar curtailment reached a new Q3 high.

What the batteries displaced

Gas-fired generation fell by 453 MW (-34%) to its lowest Q3 level, the report says, as cheaper solar charged batteries by day and those batteries covered the evening ramp that gas peakers have traditionally served. Renewables supplied a record Q3 share of 44.3% of NEM generation, up from 41.8% a year earlier, and at one half-hourly peak on Saturday 19 September renewables reached 80.4% of total generation, beating the previous record of 78.6%.

Prices followed. NEM-wide wholesale spot prices averaged $63/MWh, down $23/MWh (-27%) on Q3 2025 and the lowest Q3 average since 2021, which AEMO attributes partly to lower evening-peak demand and growing battery participation flattening the daily price curve. “Electricity use continues to grow, but more solar and storage is changing when energy is produced, drawn from the grid and shifted across the day,” said Violette Mouchaileh, AEMO’s executive general manager for policy and corporate affairs, in the accompanying media release.

Why the evening peak is the one that matters

The evening peak is the hard part of the day for a grid with a lot of solar. Demand rises as households switch on after dark just as rooftop and grid solar fade, and that ramp has long been met by gas peakers and, before them, coal. Batteries charged on cheap midday solar and discharged into that window attack exactly this problem, and the Q3 numbers suggest they are now doing so at scale rather than at the margin: a fleet that has passed 10 GW/23 GWh of installed capacity, setting prices in nearly half of all intervals, is no longer a niche participant. Underlying demand itself hit a new Q3 high of 25,471 MW, up 1.3% year on year, driven in part by data-centre load — in Victoria, data-centre demand rose from 136 MW a year earlier to 225 MW. AEMO also counts 22 data centres totalling 10.1 GW of maximum load working through its transmission connection process, a pipeline that will test how far storage can keep covering the peak as demand climbs.

The curtailment caveat

The quarter was not uniformly good news for renewables. Total network curtailment of wind and solar generation reached a new Q3 high, averaging 281 MW, up 139 MW year on year, with grid-scale solar accounting for most of the increase as network limits bit in New South Wales. In other words, the grid is still spilling clean energy it cannot move or absorb, even as batteries soak up more of it. The milestone is real, but it is a NEM-wide average across the evening peak, not a claim that batteries have replaced gas at every moment or in every region.

TSN has tracked this transition before, from the debate over batteries versus gas peakers in the US to a record 745 MW delivered by home batteries on California’s grid. In Australia, grid constraints remain a live issue: NextDC recently cut its FY27 guidance after grid works stalled at its Melbourne data-centre site.