Rio Tinto and Sumitomo Corp. plan to build a first-of-a-kind hydrogen plant in Gladstone, Queensland as part of a A$111.1 million program aimed at lowering carbon emissions from the alumina refining process.

The Yarwun Hydrogen Calcination Pilot Demonstration Program received the green light after a A$32.1 million co-funding boost from the Australian Renewable Energy Agency (ARENA). The program is aimed at demonstrating the viability of using hydrogen in the calcination process, where hydrated alumina is heated to temperatures of up to 1,000°C. It involves construction of a hydrogen plant at the refinery and the retrofit of refinery processing equipment. If successful, the program could pave the way for adoption of the technology at scale globally.

The project will consist of construction of a 2.5-MW on-site electrolyzer to supply hydrogen to the Yarwun refinery and a retrofit of one of Yarwun’s four calciners so it can operate at times with a hydrogen burner. Rio Tinto will conduct a series of tests of the hydrogen calciner under differing operating conditions to validate suitability and performance. 

The trial is expected to produce the equivalent of about 6,000 metric tons (mt) of alumina per year while reducing Yarwun’s carbon dioxide emissions by about 3,000 mt per year. Converting the entire plant to green hydrogen could reduce emissions by 500,000 mt per year, which is the equivalent of taking about 109,000 internal combustion engine cars off the road, according to Rio Tinto.

Construction will start in 2024. The hydrogen plant and calciner are expected to be in operation by 2025. If successful, the project will demonstrate the viability of hydrogen calcination and pave the way for adoption at scale across other alumina refineries. 

Sumitomo will own and operate the electrolyzer at Yarwun and supply the hydrogen to Rio Tinto directly. The electrolyzer will have a production capacity of more than 250 mt of hydrogen annually.

The pilot plant follows the success of a A$1.2 million feasibility study co-funded by Rio Tinto and ARENA that was announced in 2021. Rio Tinto Aluminum Pacific Operations Managing Director Armando Torres said the pilot plant is an important step in testing whether hydrogen can replace natural gas in Queensland alumina refineries.