Cairns Regional Council - Portsmith Landfill Gas Project

Cairns Regional Council - Portsmith Landfill Gas Project is a landfill gas (LFG) project located in the industrial suburb of Portsmith, approximately 3km south of the Cairns CBD in Far North Queensland. Registered in February 2014, the project operates at the Portsmith Landfill, a facility that serviced the region from 1985 until its closure to putrescible waste around 2011. While the exact project area is listed as unknown in the registry, the landfill site itself covers approximately 20 hectares.

The project operates under the Carbon Credits (Carbon Farming Initiative, Landfill Gas) Methodology Determination 2015. This methodology focuses on the capture and combustion of methane generated from decomposing organic waste. Specifically, this project targets "legacy waste", waste deposited prior to July 2012. By installing a gas collection system and flaring the captured methane, the project converts it into carbon dioxide, a gas with a significantly lower global warming potential. This activity prevents potent greenhouse gases from entering the atmosphere and generates Australian Carbon Credit Units (ACCUs).

The Portsmith area is situated in a tropical monsoon climate zone characterized by high rainfall and high humidity. The landfill was originally constructed on sensitive coastal land near mangrove wetlands and the Great Barrier Reef Marine Park. Consequently, the underlying soils are naturally marine clays and mangrove muds. The site underwent a major remediation and closure process involving the installation of a composite clay and geomembrane cap to manage leachate and gas migration in this wet, porous environment.

An interesting note about this project is its role in the council's broader environmental strategy. The landfill was originally unlined, making the closure and gas capture critical for protecting the adjacent World Heritage marine environment. As of 2025, Cairns Regional Council reported holding nearly 50,000 ACCUs generated from this project, debating whether to sell them for revenue or surrender them to meet internal "net zero" targets. The project previously held a contract with the Australian Government (CAC102466), which has been successfully completed.