Rio Tinto is assessing a 360 MWh thermal battery to replace fossil fuels in alumina refining, with the proposed Australian project potentially cutting annual emissions by 67,000 metric tons of carbon dioxide.
Mining giant Rio Tinto and thermal energy storage specialist Rondo Energy have commenced front-end engineering and design on a project seeking to integrate a 30 MW/360 MWh heat battery into the existing steam system at the Yarwun alumina refinery near Gladstone.
The companies said if delivered, the project would be one of the first large-scale demonstrations of thermal energy storage for industrial process heat globally, and a world-first for the alumina industry.
Kira Rundel, head of Rondo in Australia, said the project will help validate the role of thermal energy storage in reducing fossil fuel use in energy-intensive industries and pave the way for similar projects in other sectors.
“This project shows how Australia’s abundant energy can become a competitive advantage for industry,” she said. “Heat batteries allow manufacturers to use low-cost electricity to produce the reliable, round-the-clock heat their operations need.”
The project, supported by a grant from the Australian Renewable Energy Agency (ARENA), will seek to integrate a 30 MW / 360 MWh thermal energy storage unit into the Yarwun refinery’s existing steam system.
Rondo said its heat batteries, built on proven refractory brick materials as the thermal storage medium, can store low-cost grid electricity generated during sunny and windy hours as high-temperature heat for days and release it when needed to generate steam for industrial operations. The company said the heat is typically delivered as steam or hot air up to 1,000°C and the technology has a round-trip efficiency of more than 98%.
California-headquartered Rondo said for energy-intensive industries such as alumina refining, the heat batteries offer a fast, low-cost pathway to electrification that addresses both emissions and energy costs.
“Because the heat battery slots into the existing steam network, the facility’s processes run exactly as before, the only thing that changes is the energy for that heat: no longer from fossil fuels, but sourced from low-cost electricity instead,” the company said.
The Yarwun study will assess the technical and economic viability of integrating the technology into the refinery operations.
Alumina refining is a notoriously hard-to-abate industry and Rio Tinto Pacific Operations Managing Director Armando Torres said industrial process heat remains one of the toughest decarbonization challenges.
“Reducing emissions from alumina refining is complex, particularly when it comes to generating the high-pressure steam needed for our operations,” he said.
“This study will help us determine whether thermal energy storage can provide a technically and economically viable alternative to fossil fuels for part of Yarwun’s steam requirements.”
If the Yarwun project is progressed, it is expected to cut onsite emissions by about 67,000 tonnes of carbon dioxide each year.
ARENA’s funding for the project will be delivered in two phases, with an initial AUD 3.6 million ($2.5 million) to complete front-end engineering and design work, followed by up to AUD 38 million for full-scale construction and commissioning should the project proceed, as well as up to AUD 33.3 million in conditional contingency support.
ARENA Chief Executive Officer Darren Miller said technologies such as thermal energy storage need to be tested in real large-scale operating environments before they can be adopted more broadly across Australian industry.
“This project will test whether thermal energy storage can provide a practical pathway to lower emissions from industrial heat in a real-world operating environment, where reliability, performance and integration are critical,” he said. “Demonstrations like this will help build the evidence industry needs to make future investment decisions so the value of this project extends well beyond a single refinery.”
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