​Transmission constraints have been a problem for New South Wales in 2025. They have prevented low-priced renewable generation in the South West from reaching demand centres, creating the conditions for increased volatility. And they’ve made it difficult for batteries in constrained regions to dispatch into these price spikes, costing these systems money.
Smart optimisers have found ways to maximise output during price spikes, even whilst constrained. However, last week, multiple different batteries were caught charging during price spikes - showing constraints can still cause problems.
New South Wales saw back-to-back extreme price spikes on 20 and 21 November, each hitting $14k/MWh for a single interval (13:25 on the 20th, 09:10 on the 21st). Five different batteries charged across the two spikes, costing operators between $600/MW and $1,100/MW per MW, equivalent to around 20% of their November revenue so far.
Despite involving different assets on different days, the two events shared a common root cause: network constraints that triggered locational price adjustments, while demand steeply ramped up between dispatch intervals.
This article examines the conditions that caused the price spikes, the impact on batteries from the two events, and how locational pricing and bid dynamics led batteries to charge whilst prices hit $14k/MWh.
This article was updated on 27 November 2025 following a further two price spikes in New South Wales.
Update: Further price spikes hit NSW as batteries recover losses on 26 November
Following the price spikes on 20 and 20 November, this following week New South Wales saw a further two days with price spikes: 25 and 26 November. Batteries managed to increasingly shift their positions from importing to exporting across both later price spikes, ultimately ending up in a net positive revenue position across the four days.
