Gunvor Takes 600MW South Australia Supply Position as NEM Contracts Shift Toward Time-of-Delivery Value
A 12-year Firmus deal illustrates how commodity capital is moving into structured NEM supply arrangements priced on when energy is delivered, not just how much.
Swiss commodity trading firm Gunvor has agreed to a 600MW, 12-year renewable supply contract covering South Australia with developer Firmus, a deal WattClarity cited on Wednesday (2026-09-23) as an example of how power purchase agreements in the National Electricity Market are being repriced around delivery timing rather than volume alone.4
WattClarity framed the contract in the context of a broader market evolution: from agreements built around volume delivery toward structures that price the ability to supply energy at the right time and in the right location. ERM Power had made a version of this argument in early 2025, contending that a critical market segment had been overlooked by the energy transition. South Australia's day-ahead spot power stood at A$111.36/MWh on Wednesday (2026-09-23), a market where intraday price spreads can be wide enough to make delivery timing commercially significant.4
August 2026 battery fleet data illustrate both the opportunity and the gap between intent and execution. Australia's 58 grid-scale battery systems in the NEM generated a combined AU$28.79 million in estimated gross energy and frequency control ancillary services revenue during August, according to NEMPulse — up 6% from July's AU$27.22 million. Normalised for fleet growth and time, revenue fell 4% to AU$103/MW/day over the same period.3
The divergence reflects a fleet growing faster than its collective capacity to capture available value. Total NEM battery capacity reached 8,983MW and 21,539MWh by end-August 2026, NEMPulse reported. The fleet's capture rate — the share of revenue earned against a perfect-foresight trading strategy — improved from 48% in July 2026 to 54% in August. An estimated AU$23.35 million remained uncaptured across the month.3
Performance varies sharply across the fleet. Limondale Battery led on energy capture at 81%, followed by Woolooga BESS at 77% and Supernode BESS at 76%, while Bulgana Green Power Hub, Phillip Island BESS and Pine Lodge posted materially weaker results, NEMPulse data show. The spread between top performers and the fleet average measures how much value-based contracting can improve on simple volume offtake — if the trading infrastructure can keep pace.3
Spread compression is working against pure arbitrage strategies. The average daily price spread across the NEM's five regions — the top two hours minus the bottom two hours — fell 27% to AU$110/MWh in August. Intraday spreads at that level still reward precise dispatch, but they leave less room for error as the battery fleet scales.3
Curtailment data reinforce the market's direction. Across the mainland NEM, the Curtailed Flexibility Dividend — a measure of the economic value of generation curtailed rather than dispatched — rose from AU$27 million in 2020 to AU$328 million in 2025, PV Magazine Australia reported. Energy is being spilled increasingly during periods with real earning potential, not just predictable midday oversupply.1
New demand is adding weight to the shift. Origin Energy's March 2026 quarterly report showed data centres drove a 4% increase in NEM electricity sales volumes compared with the March 2025 quarter. Data centre load — large, stable, and creditworthy — tends to attract bilateral supply structures rather than spot exposure, pushing demand toward contracts that can guarantee delivery on a defined schedule.2
For Gunvor, the 12-year position is a bet that it can monetise NEM price shape across a decade of grid evolution, network constraint changes, and regulatory shifts that neither party has publicly mapped out. The AU$23.35 million left on the table by Australia's 58 NEM batteries in August 2026 alone suggests that closing the capture gap — not just designing value-based contracts — is where the next margin will be won or lost.3,4