Optimise alumina processing temperature at Yarwun refinery (Revoked)

Optimise alumina processing temperature at Yarwun refinery (Revoked) was an industrial energy efficiency project located at the Rio Tinto Yarwun Alumina Refinery, approximately 10km north-west of Gladstone in Central Queensland. Registered in September 2018, the project operated within the heavy industrial zone of the Gladstone State Development Area. While the immediate site is dedicated to large-scale alumina processing and port activities, the broader Gladstone region is characterized by a mix of cattle grazing, forestry, and significant industrial infrastructure.

The project was registered under the Carbon Credits (Carbon Farming Initiative-Industrial Electricity and Fuel Efficiency) Methodology Determination 2015. This methodology credits activities that improve the energy efficiency of industrial equipment, such as boilers, furnaces, or heating systems, by upgrading technology or optimizing control systems to reduce fuel or electricity consumption. In this specific instance, the project focused on optimizing processing temperatures to reduce the fuel required for process heat. The project was voluntarily revoked in December 2022, just prior to the broader methodology being replaced by the new Industrial and Commercial Emissions Reduction (ICER) method in January 2023.

Environmentally, the Gladstone region experiences a subtropical climate with summer-dominant rainfall, averaging around 800mm to 900mm annually. The soils in the surrounding area are variable, often consisting of texture-contrast soils such as chromosols and sodosols, alongside coastal claypans and calcareous loams found in the undulating rises north of the city.

An interesting development at the Yarwun site is Rio Tinto's shift toward more advanced decarbonization technologies. Following the revocation of this efficiency project, the refinery has become the site of a world-first hydrogen calcination pilot program. Partnering with Sumitomo Corporation and supported by ARENA, Rio Tinto is constructing a hydrogen plant to trial replacing natural gas with hydrogen in the alumina refining process, marking a significant evolution from the earlier temperature optimization activities.