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Rio Tinto and Rondo Energy begin design work on Australia's largest thermal battery at the Yarwun alumina refinery

Rio Tinto and Rondo Energy have started front-end engineering and design on a 360 MWh Rondo Heat Battery at the Yarwun alumina refinery in Queensland, backed by staged ARENA funding of A$3.6 million for the study and up to A$38 million for deployment - a world-first application of thermal storage to alumina refining.

By Greener Numbers Editorial Team · Published October 21, 2026 · Updated 10/21/2026

Rio Tinto and Rondo Energy have started front-end engineering and design (FEED) on a 360-megawatt-hour thermal energy storage project at Rio Tinto's Yarwun alumina refinery near Gladstone, Queensland, the companies announced on October 21, 2026.

The planned Rondo Heat Battery is rated at 360 MWh of storage, 78 megawatts of electrical charging capacity and 30 megawatts of thermal discharge. If the study supports construction, it would be Australia's largest thermal energy storage project, one of the first large-scale demonstrations of thermal storage for industrial process heat anywhere, and a world-first for the alumina industry.

The Australian Renewable Energy Agency is funding the project in stages under its Industrial Transformation Stream: an initial A$3.6 million for the FEED study, up to A$38 million for deployment if the study succeeds, and a further A$33.3 million in conditional contingency support that would only be released in defined circumstances such as cost overruns or elevated electricity costs. ARENA expects the unit to cut on-site emissions by around 67,000 tonnes of carbon dioxide a year.

Alumina refining depends on round-the-clock, high-pressure steam that today comes almost entirely from burning fossil fuels. Rondo's design charges refractory brick with low-cost electricity during Queensland's midday solar surplus, then releases the energy continuously as steam or hot air at up to 1,000 degrees Celsius directly into the refinery's existing steam network, so the plant's processes run unchanged.

The FEED framing matters: this is a design and viability study, not a construction commitment. Rio Tinto said the study will assess whether thermal storage is technically and economically viable for part of Yarwun's steam requirements, and ARENA's later tranches depend on its outcome. Rondo's Head of Australia, Dr. Kira Rundel, said the project would show that factories can cut emissions without increasing energy costs.

If built, the project would test a decarbonization path for one of the hardest-to-abate industrial processes - continuous high-temperature steam - using a storage medium (brick) with no scarce minerals and no degradation-limited cycle life, at a refinery scale that other Australian smelters and refineries could follow.

Official source: rondo.com ↗