CIS-backed big battery hits full power and passes final tests to join the grid

The 240 MW Mornington battery in Victoria has passed final commissioning tests and reached full capacity. The project took more than five years from proposal to operation and changed hands twice, most recently moving into joint ownership by BW ESS and Gaw Capital Partners (via Valent Energy) in 2024. It was one of 16 projects to secure federal underwriting under the Capacity Investment Scheme.

Where this fits

This is a data point on reliability, not a solution to it. A 480 MWh battery can discharge at full power for only two hours before depleting entirely. On a grid where wind and solar output can slump for days, a big battery buys time measured in multiples of hours, not the days or weeks that a cold front or high-pressure system can suppress renewable generation. The Mornington asset adds dispatchable capacity, as the operator rightly notes, but it remains a firming aid to weather-dependent sources, not a replacement for firm baseload power. The project's ownership path through Hong Kong and Singapore firms also reflects a pattern: Australia builds storage and renewable infrastructure financed and, increasingly, controlled offshore, while the supply chain for batteries, inverters and panels runs through China's factories.

What it means

The battery will help smooth volatility and meet peak demand on good days for wind and solar. It does not solve the core problem of a grid increasingly dependent on weather, on Chinese manufacturing of critical components, and on gas plants as the only dispatchable backup at scale. A firm, low-material, long-lived alternative, nuclear, remains prohibited by law. Australia is building the transmission, storage and gas infrastructure to support renewables at high whole-system cost, while foreclosing the lower-emission firm option.