Rio Tinto and California-based Rondo Energy are studying a large thermal battery at the Yarwun alumina refinery near Gladstone, Queensland. The system would use electricity to heat refractory bricks, then release that heat as steam for the refinery's existing network, replacing part of the coal and natural gas currently used. Rondo describes it as Australia's largest planned thermal storage project and a first for alumina refining.
The proposed battery would store 360 MWh of heat and deliver up to 30 MW, with an electrical charging capacity of 78 MW. Rio Tinto estimates it could meet about 5% of Yarwun's steam demand and cut direct emissions by roughly 67,000 metric tons of CO2 annually. The broader alumina sector accounts for about 175 million tonnes of CO2 equivalent each year, so the project is a test case for cutting industrial heat emissions.
The feasibility study will take about 12 months. ARENA is contributing A$3.6 million for the study, with Rio Tinto matching that amount. If the project proceeds, ARENA could provide up to A$38 million for deployment plus A$33.3 million in contingency support, and Rio Tinto says its total investment would exceed that. The companies say the battery would let the refinery use low-cost electricity to produce reliable, round-the-clock heat, though the study will need to confirm the economics and integration with existing equipment.