Rio Tinto wants to store cheap midday power as heat in bricks to cut fossil fuel use at an Australian refinery

Rio Tinto has begun engineering work on a heat battery that would soak up cheap midday electricity, store it as heat in refractory bricks and hand it back as steam at its Yarwun alumina refinery near Gladstone, Queensland. The study was announced on Oct. 21 and is expected to run about 12 months.

Save more, waste less: The Cool Down’s newsletter sends smart, simple changes that help you and the planet in your everyday life.

Subscribe to The Cool Down →

We may earn a commission if you sign up.

Alumina refining depends on large volumes of steam, and the plan is aimed at cutting the fossil fuel used to make it. Armando Torres, managing director of Rio Tinto Pacific Operations, described generating high-pressure steam as the hardest part of cutting emissions from the industry, and the company is now testing whether stored solar-hour power can take over part of that job. Nothing has been built yet, and Rio Tinto says the study’s findings will inform whether the project moves to execution. Torres said the study will help the company determine whether thermal energy storage can be both technically and economically viable at the refinery, which is the real question behind the engineering.

Rondo’s refractory-brick heat battery

The technology comes from California-based Rondo Energy. According to Rio Tinto’s own announcement, the system converts electricity into heat held in refractory bricks, the same heat-resistant material that lines furnaces and kilns, and releases that heat as steam. Rio Tinto said it chose the approach for its technical maturity. Electrek’s report on the plan put it in plain terms: the company wants to store cheap midday electricity as heat in bricks, and the stored heat would produce steam after sunset, when solar output has faded and the refinery still needs a steady supply.

The design details matter because they explain why the idea is attractive. Energy-Storage.News reported a storage capacity of 360 megawatt-hours, charging at up to 78 megawatts and discharging heat at up to 30 megawatts, enough to run for about 12 hours at full output. Rondo says Australia regularly has four to six hours of surplus midday solar power, and the battery stretches those hours into round-the-clock heat.

Because the battery plugs into the refinery’s existing steam network, the plant’s processes would run as they do now. Only the energy source changes. Rondo adds that its systems began delivering heat and power at scale in 2023, so the underlying equipment is not experimental even if this particular installation would be the largest of its kind planned in the country. Kira Rundel, Rondo’s head of Australia, said the project shows how “Australia’s abundant energy can become a competitive advantage for industry.”

ARENA’s A$3.6 million study grant and the money behind it

Public money is doing much of the early lifting. The Australian Renewable Energy Agency is providing A$3.6 million for the front-end engineering and design study, and Rio Tinto says it will match that amount. If the study succeeds and the project proceeds, ARENA has indicated up to A$38 million for deployment, plus as much as A$33.3 million in conditional support for defined risks, among them electricity costs and cost overruns. Rio Tinto expects its own total investment to exceed ARENA’s contribution if construction goes ahead.

ARENA’s chief executive, Darren Miller, called industrial heat one of the toughest decarbonisation challenges facing heavy industry, and the Yarwun study is one test of whether stored electricity can replace fuel for that heat.

Five percent of Yarwun’s steam and 67,000 tonnes of carbon dioxide

The expected benefit is real but modest. Rio Tinto estimates the heat battery could supply about 5% of Yarwun’s steam requirements and cut the refinery’s direct, Scope 1 emissions by about 67,000 tonnes of carbon dioxide a year. That is a meaningful slice for a single demonstration unit, yet it leaves the other 95% of the steam to existing boilers, which is why the company describes the work as a demonstration rather than a full conversion. The refinery’s boilers would keep running for the bulk of its steam, and the economics of the battery depend heavily on how cheap the midday electricity actually is, one of the risks the ARENA contingency money is meant to cover.

The wider stakes are larger. The Electrek report cites roughly 175 million tonnes of carbon dioxide-equivalent a year from refining in the global aluminium sector, so a technology that proves out at Yarwun could be copied at plenty of other plants. Rondo calls the project the largest planned thermal storage installation in Australia and a first for the alumina industry.

Heated bricks are already moving into other industries

The Yarwun study follows other brick-based heat batteries. In Germany, Rondo and the chemical company Covestro began work in January 2026 on a 100 megawatt-hour unit at Brunsbüttel that is expected to supply about 10% of that site’s steam. A trade report on the Yarwun plan calls it potentially a world first for the alumina industry, a claim that only the completed study, and then a working plant, can test.

Energy-Storage.News also lists other recent thermal storage moves in the region and beyond. In May 2026, MGA Thermal and Knode began a study for a 195 megawatt-hour system at Tronox’s Kwinana facility in Western Australia, backed by A$2.95 million from ARENA. In October, Antora Energy announced a 5.8 gigawatt-hour multi-day storage project for a biorefinery in Kansas, and Rondo’s own next unit, a 100 megawatt-hour system for a European chemical plant, is under construction. ARENA’s Industrial Transformation Stream, which funds the Yarwun work, has a third round open for applications.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

Save more, waste less: Subscribe to The Cool Down →

We may earn a commission if you sign up.