Grid batteries set the NEM spot price in 36% of intervals in the June quarter, up from 17%, and the discharge price fell to $107
AEMO's June quarter 2026 report says grid batteries set the National Electricity Market spot price in 36% of dispatch intervals, up from 17% a year earlier. When battery discharge set the price, the average was $107/MWh, down from $478. These are grid batteries, not the box on a factory wall.
The batteries that set the wholesale price are not the box in a warehouse. In the June quarter they were in the market a lot more, and the price they set on the way out was much lower.
AEMO's Quarterly Energy Dynamics for 1 April to 30 June 2026 says grid-scale battery charging and discharging set the National Electricity Market spot price in 36% of dispatch intervals. A year earlier the share was 17%. Charging set the price in 19% of intervals. Discharging set it in 17%. AEMO says each of those two rose 9 percentage points on the year. 19 plus 17 is 36, by our arithmetic, which matches the combined figure in the report.
When discharge was the price-setter, the average price was $107 a megawatt-hour. In the June quarter of 2025 that average was $478. AEMO says batteries are setting prices across ordinary hours now, not only in the spikes. The fall from $478 to $107 is $371 a megawatt-hour, by our arithmetic.
The whole-market average spot price was $74/MWh, down $66, or 47%, on the year. AEMO calls it the lowest June-quarter average since 2020.
The clock matters. In the evening peak, 4pm to 9pm, battery discharge set the price in 46% of intervals, up 24 percentage points. In daylight, 10am to 4pm, battery charging set the price in 41% of intervals, up 21 percentage points. Daytime charging volume rose by 1,009 MW, or 211%. Evening discharge rose by 1,066 MW, or 228%.
By state, in the same report: Queensland charging 24% of intervals and discharging 21%. New South Wales is listed as 25% and 21% in that same charge-then-discharge order. Victoria's charge and discharge together were 39% of intervals. South Australia's were 40%.
Analogy: the spot market is a cattle auction. A year ago the battery bidder mostly showed up when the price went wild. This June quarter it was in the ring for more than a third of the lots, and the lots it cleared on the way out averaged $107, not $478.
This is grid-scale storage. It is not a quote for the battery on a factory wall. A workplace battery does not bid in the spot market on its own. A retailer or an aggregator stands in between. A demand charge is a different line on the bill, and this report does not price it.
The report is dated July 2026. AEMO's media release is 28 July 2026. It is the latest Quarterly Energy Dynamics on the operator's page. It is not this week's prices.
On 14 October 2026 a pv magazine Australia column aimed the 36% and 17% figures at commercial buyers. Those two figures match the report. The column also walks a made-up 500 kW / 1 MWh battery buying at $50/MWh and selling at $300/MWh, and it says the $220 gap is not profit. Those prices are the author's illustration. They are not in the AEMO report. We are not using them as a market price.
Good: A public report, a before-and-after share, and a clear drop in the price batteries set when they are the marginal unit.
Bad: The quarter closed on 30 June. A factory signing a battery this month is not trading into these exact hours. Network charges, retail margins and export limits sit outside the $107.
Ugly: A design sold on last year's $478 spike is aimed at a price that shrank. And a battery emptied into the evening peak can be empty when the site's own peak arrives. One box does not do both jobs in the same hour.
Soft next step: split the bill into demand charges and energy charges, and ask who controls a battery at 4pm if wholesale trading is part of the pitch. Then a short consult at Sovryn Energy /consult if you want that read against 12 months of interval data.
Source: AEMO, Quarterly Energy Dynamics Q2 2026 (July 2026). Primary for 1 April to 30 June 2026, batteries setting the spot price in 36% of dispatch intervals versus 17% in Q2 2025, charge 19% and discharge 17% (each +9 percentage points), discharge marginal price $107/MWh versus $478/MWh, NEM average $74/MWh (down $66, or 47%), evening peak (1600-2100) discharge price-setting 46% (+24 percentage points), daylight (1000-1600) charging price-setting 41% (+21 percentage points), daytime charging +1,009 MW (+211%), evening discharge +1,066 MW (+228%), Queensland 24% / 21%, New South Wales 25% / 21%, Victoria 39% and South Australia 40% combined. AEMO media release, 28 July 2026. Date and the $74/MWh, 47% fall summary. pv magazine Australia, 14 Oct 2026 - Beyond peak shaving. The column's 36% and 17% match the report. Its $50 / $300 / $220 trading sketch is the author's hypothetical, not an AEMO price. $371/MWh and 19 + 17 = 36 are our arithmetic.