Rio Tinto has signed an agreement with Australian bioenergy company SuperChar (SCL) to reduce reliance on fossil fuels at its Gladstone alumina refineries.

Under the five-year agreement, SCL will supply locally produced bio pellets, with deliveries targeted to commence in 2028.

The deal follows Rio Tinto operational trials and a feasibility study.

It represents the next stage in assessing the use of bio pellets as one of several potential solutions the company is exploring to reduce reliance on fossil fuels in alumina refining.

The trials tested a range of bio pellet and coal blends and demonstrated that bio pellets, under trial conditions, could replace up to 30% of the coal used to generate steam in the refinery boilers.

Under the agreement, Rio Tinto plans to undertake a range of operational demonstrations and assessments of bio pellet blends - ranging from 5 to 50% bio pellets - as a supplement to coal used in boilers at its Gladstone alumina refineries.

Initial use of SCL's bio pellets is expected to begin at Yarwun, followed by increasing volumes at Queensland Alumina, subject to appropriate approvals and operational readiness at both sites.

Armando Torres, Rio Tinto Aluminium Pacific Operations Managing Director, said: “Reducing our alumina refineries’ reliance on fossil fuel will require a mix of technologies, innovation and partnerships, and bio pellets are one of the practical options we are exploring as part of that.

"The recent trials and feasibility study have given us valuable insights, and this agreement allows us to take the next step in understanding how bio-pellets could work in practice and be scaled for use at our Gladstone operations.”

The initial offtake agreement with SCL will enable Rio Tinto to further assess the potential role of bio pellets, with scope to increase supply over time if the project is successful.

SCL plans to establish a bio pellet production facility in the Gladstone region which will use locally grown bana grass as the feedstock.

Bana grass is a high-yielding perennial energy crop suited to Central Queensland.

It can be planted and harvested using conventional sugar cane equipment and remains productive for more than 15 years.

The facility will initially have capacity to produce 35,000 tonnes of bio pellets a year.

At full contract volumes, it could reduce reported Scope 1 emissions by up to 90,000 tonnes of CO₂e annually, under Australia’s current National Greenhouse and Energy Reporting framework.

SCL is targeting the progressive roll-out of bana grass planting from late 2026, with the production of bio pellets processing to begin in 2028.