Gas produced by landfill is being captured and turned into energy to power Canberra homes

Energy generated from methane produced by Canberra’s main rubbish tip is expected to power 10,800 homes and further cut greenhouse gas emissions under an expanded capture project.

About 300,000 tonnes of waste go to landfill each year in the territory, with roughly half of that amount classified as organic waste, such as food and wood products.

When organic waste decomposes it generates harmful gases, including methane, which is 28 times more potent than carbon dioxide at producing the greenhouse effect driving global warming.

Since 2020, gases emitted from organic waste at the Mugga Lane landfill in Canberra’s south have been captured and then converted into electricity for homes and businesses in the territory.

LGI chief operating officer Jarryd Doran said the facility, along with a landfill gas flaring project in West Belconnen, had already helped the ACT government reduce carbon emissions by 963,000 tonnes.

“You’d need to plant 16 million trees to achieve an equivalent or comparable level of abatement,” he said.

“It’s a very efficient way of reducing emissions. The beauty of it as well is it’s measurable and it’s irreversible.” 

Now the ACT government and renewable energy provider LGI are expanding the facility, with the addition of two gas-to-electricity generators, on top of the four existing ones.

A 12-megawatt battery storage will also be added, as well as a 20-megawatt grid connection with Evoenergy.

Mr Doran said those upgrades would take the current 4-megawatt facility to 20 megawatts, producing 50,000 megawatt hours of “dispatchable” energy per year. 

“With the 4-megawatt facility we’ve produced enough energy to power around 7,500 homes on a typical yearly basis, and this upgrade will allow us to power more than 10,000 homes,” he said.

How the capture and conversion process works

The organic waste in the landfill generates methane, carbon dioxide and other gases as it decomposes.

A network of vertical wells and horizontal pipes embedded in the landfill capture that gas under vacuum.

The captured biogas is then combusted in a gas engine, to generate renewable electricity, which is exported via a transformer to the electricity grid.

Excess gas is burned off through a flaring unit, which, like the combustion process, stops the methane from going into the atmosphere by converting it into CO2 and water. 

“There is still a by-product of that overall outcome, but the by-products are significantly less than if the gas from the landfill had gone directly to the atmosphere,” Mr Doran said. 

“So, there’s a massive reduction in the impact there in a positive way.”

LGI says the landfill gas can also be temporarily stored so the facility can generate and dispatch electricity when demand peaks.  

ACT City Services Minister Chris Steel said capturing landfill emissions was a key part of the territory’s waste strategy with organic waste still being sent to the tip. 

The rollout of the government’s food organics and garden organics (FOGO) collection service and the construction of a new processing facility were pushed back after fire destroyed Canberra’s recycling facility at Hume. 

“We can’t capture all of it, so, we’re trying to stop organic material going in there in the first place,” Mr Steel said. 

“But there will be some organic material in there still for decades to come. 

“So, the opportunity to be able to generate electricity from that methane gas and stop it going into the atmosphere is a really good one.”

‘A stable energy source’ 

Mr Doran said an under-appreciated benefit of the Mugga Lane facility was that it could be a stabilising energy source for the territory, when solar and wind contributions to the distribution network dipped.

“By capturing that biogas and converting it into electricity you can end up with a very reliable, very predictable form of renewable energy, unlike the variability of wind and solar,” he said. 

“The batteries coming in the distribution network will also help bolster and stabilise the grid for the energy transition [to renewables].” 

Work on the new facilities has already begun and is expected to be completed by the end of 2025. 

“The two extra generators have arrived on site … and our plan is to have them online by the middle of next year,” Mr Doran said.

“The batteries we’re hoping would be on site about 12-18 months after that.”