WattClarity Says 19 GW of Batteries Will Eviscerate Australian Coal Profits
A new analysis of Australia's utility storage pipeline projects that coal generators will lose their last reliable revenue window once the buildout is complete.
A WattClarity analysis published Sunday (2026-09-06) concluded that some coal generators in Australia's National Energy Market face closure once a projected 19 GW and 55 GWh of utility-scale battery storage reaches full operation. The judgment was direct: coal profits "will be eviscerated."5
The evening peak has been coal's commercial last stand. As solar generation collapses after sunset, demand holds, giving coal plants the pricing window they need to recover fixed costs. Batteries sized at 55 GWh are built to eliminate that window, absorbing midday cheap solar and discharging through peak hours. WattClarity's analysis takes its title from precisely that mechanism: what the incoming battery fleet should do to coal's evening peak.5
Australia has moved quickly to get there. Reneweconomy reported in late May (2026-05-25) that the country had become the world's third-largest utility-scale battery market. On the household side, 268,675 home batteries were purchased in 2025, up from 74,582 in 2024, with discharge levels more than doubling across all states.1
That buildout helped push renewables to 42.7 per cent of Australia's full-year electricity mix in 2025, up from 39 per cent in 2024, the first time, Reneweconomy noted, renewables had crossed that threshold in Australian history.1
The WattClarity analysis does not dismiss the risks. Drought can restrict hydro, particularly in Tasmania. Wind can drop. Heat can push demand above seasonal norms. The analysis argues that even stacking those factors together, the economics for coal darken once 19 GW of storage is operating.5
That claim will be tested against the grid's real behaviour. In the week of 22 June 2026, the NEM suffered a prolonged wind drought alongside low winter solar output, leaving the system heavily dependent on coal and gas. Grid analysts observed at the time that network adequacy must be designed around worst-case events, not average conditions.4
The AEMO had been keen to highlight storage successes from the previous Australian summer. CEO Daniel Westerman, writing in June (2026-06-12), cited 27 January performance in Victoria as evidence of battery reliability under stress. But a two-day heatwave around the same period in June depleted battery reserves and drove gas costs sharply higher, nearly doubling quarterly settlement costs in parts of the NEM, according to Reneweconomy.3
Coal's current market position reflects pressure from both ends. Newcastle thermal coal physical prices sat at $138.75 per tonne as of 2026-09-09, while the COAL sector ETF fell 1.35 per cent in the same session. Wholesale electricity in Australia has averaged around $100 per MWh since the post-2022 spike following Russia's invasion of Ukraine, roughly double the pre-conflict level, according to industry participants quoted by the ABC in February (2026-02-07). That elevated average has provided coal operators some revenue cover. The storage pipeline threatens to remove it.2
The 19 GW and 55 GWh figure is a pipeline projection, not a connected fleet. Project timelines, grid connection delays, and battery performance across back-to-back stress events — a repeat of the June wind drought paired with a heatwave — remain the key variables. The June experience showed the gap between pipeline ambition and operational reality is not yet closed.5,4,3