Plans for an ambitious $1.8 billion pumped hydro project in northern New South Wales have collapsed after developer Alinta Energy deemed the infrastructure commercially unviable, dealing another blow to the state's transition.
The proposed 600-megawatt Oven Mountain Pumped Hydro Energy Storage scheme, situated between Armidale and Kempsey, had been earmarked as a vital component of the New England Renewable Energy Zone. The facility was designed to provide long-duration firming power capable of supplying up to 72 hours of continuous electricity into the National Electricity Market.
However, ABC News NSW reported that Alinta Energy has formally halted development after an extensive assessment concluded that surging capital costs and complex geological parameters made the project economically untenable.
Blow to state's clean energy pipeline
The abandonment of Oven Mountain strips a cornerstone asset from the state government’s blueprint to replace its ageing fleet of coal-fired generators. Under the Electricity Infrastructure Roadmap, NSW requires significant dispatchable capacity to maintain grid reliability as baseload facilities near the end of their operational lives.
State energy authorities had previously declared the scheme a Critical State Significant Infrastructure project, conferring priority assessment status and backing it with millions of dollars in preliminary planning grants. Despite this regulatory support, macroeconomic headwinds facing the broader construction and civil engineering sectors proved insurmountable.
Escalating costs derail Oven Mountain
Alinta’s decision underscores the severe commercial headwinds facing large-scale pumped hydro developments across Australia. Engineering requirements for deep underground caverns, steep water conduits, and remote transmission connections have consistently driven project budgets well beyond initial feasibility estimates.
Supply chain disruptions, inflationary pressures on heavy industrial machinery, and acute shortages of specialised tunnelling labour have compounded the difficulty of delivering civil works on time and on budget. Similar cost blowouts have affected other major storage developments across the country, most notably the federal government's Snowy 2.0 initiative, dampening commercial appetite for massive civil-heavy ventures.
Storage deficit looms over coal closures
The cancellation intensifies pressure on energy planners to secure alternative medium and long-duration storage before the scheduled retirement of major coal assets. While the Minns government negotiated an extension to keep the Eraring power station operating until 2027, the window to commission replacement firming capacity remains exceedingly narrow.
Energy market analysts warn that while short-duration chemical battery systems are deploying rapidly across NSW, they cannot readily replicate the multi-day energy reserves offered by pumped hydro during periods of prolonged cloud cover and subdued wind generation.
With Alinta relinquishing its interest in Oven Mountain, regional stakeholders and grid planners face an uphill battle to restore investor confidence in complex storage infrastructure, leaving the state increasingly reliant on large-scale battery developments and gas peakers to bridge the energy deficit.