Work is underway on Mugga Lane landfill gas-to-energy.
Project description
Capturing gas produced in landfill is an important part of managing our impact upon the environment and reducing pressure on natural resources.
The ACT generates approximately one million tonnes of waste each year, of which it recovers about 70%. The remaining waste that can’t be reused, recycled or recovered is disposed of in landfill.
Mugga Lane is the main ACT landfill site and has been in use since the 1970s.
The problem
Over time the organic matter buried in a landfill undergoes anaerobic decomposition (without oxygen) and generates gases including methane. When released into the atmosphere, methane acts as a greenhouse gas trapping heat and contributes to global warming at 25 times the rate of carbon dioxide. Up to 50% of all waste in landfill is organic matter such as food, textiles, timber and household waste.
The solution
Landfill gas capture and processing technology transforms waste into a valuable resource: energy. LGI Limited (LGI) is contracted to the ACT Government to undertake gas capture and power generation at the Mugga Lane landfill gas power station.
In 2023 the ACT Government extended the existing partnership with LGI to deliver a landfill gas-to-energy expansion project at the Mugga Lane landfill. The expansion project will take place on an additional parcel of land adjacent to the current site and will further enhance the capabilities for capturing harmful methane emissions generated at Mugga Lane landfill and transforming them into reliable renewable energy for the ACT. Key features of the expansion include the establishment of two additional 1 MW generators, the installation of 12 MW of battery storage and a grid connection with Evoenergy with a 20 MW capacity.
The gas collected and processed by LGI at the Mugga Lane landfill gas-to-energy facility can power 5,700 homes. Four biogas fuelled generators have been installed by LGI which each generate 1.06 MW per hour, resulting in an estimated 37,000 MWh of green electricity every year.
Once the expansion project is complete it is anticipated the Mugga Lane landfill gas facility will generate 50,000 MWh of dispatchable energy, which is enough energy to power approximately 10,800 homes in the ACT for one year.
The benefits to the community include:
- reduction in greenhouse gas emissions
- power generation
- less demand on fossil fuel sources.
The capture also reduces health and safety issues such as odour emissions and the potential for landfill fires exacerbated by gases. The ACT Government is committed to reducing waste generation and increasing resource recovery.
How it works
- The gas must be continually extracted under pressure from the landfill to prevent the landfill gas escaping and allow back up capacity to be available for maintenance.
- The captured landfill gas first enters the thermal chamber of the facility and is cooled to below 6 degrees Celsius.
- Cooling the gas enhances the removal of condensation, the foul-smelling hydrogen sulphides, ultimately drying the landfill gas.
- The dried landfill gas is then pressurised and directed into a scrubber/filter which removes the siloxanes that would otherwise clog the internals of the engines. The main source of siloxanes in a landfill are body wash, shampoo and soap products. The scrubber has a self-cleaning cycle where it shuts down and regenerates the media to ensure maximum siloxane removal occurs. The landfill gas is now dry, clean, and pressurised in preparation for the engines.
- The gas is burnt in the combustion chamber of the four V20 gas engines, driving the generators, producing the green electricity exported to the local power grid.
- There are two back up flares used to burn off the excess gas, if necessary.
