Clean energy from trash

The City of Sydney has drafted a waste management plan that could see rubbish that would previously have been sent to landfill converted into renewable gas energy.

The proposed plan would deliver energy from waste by recovering material and energy resources from non-recyclable waste, converting non-recyclable waste to renewable and non-fossil fuel gases, and converting these gases into substitute natural gases to inject into the gas grid to deliver low-carbon energy.

Lord Mayor Clover Moore said landfill sites produce huge amounts of methane, a greenhouse gas with 25 times the global warming potential of carbon dioxide.

“It’s estimated this new technology could prevent around 196,000 tonnes of greenhouse gas emissions a year, equivalent to taking 43,556 cars off the road.

“The technology will also save ratepayers about $3.9 million a year by avoiding the waste levy costs of landfill. Every tonne of waste to landfill incurs a NSW waste levy of over $100.”

Under current estimates of population growth, Sydney’s current landfill sites would be full around 2021, with the next nearest facility 250km away.

“Currently over 40,000 tonnes of household rubbish a year is processed to remove recyclables and produce low-grade compost but one third of waste still goes to landfill.

“The advanced waste treatment plant could reduce this amount to virtually nothing.

“If we don’t try to reduce our waste, by 2030 the household waste of city residents is predicted to grow to 80,000 tonnes.

“This means after recycling and treatment, 27,000 tonnes of non-recyclable household waste would end up in landfill, equivalent to the weight of a cruise ship.”

Operating under NSW’s current regulatory environment, advanced waste treatment can be effectively used to deliver renewable gas straight to the grid.

This substitute natural gas can be used for electricity generation, heating, cooking and air-conditioning.

This system is also designed to be able to fully integrate with future trigeneration plants to produce clean, local electricity, heating and cooling.

In Australia there are multiple facilities generating power from wastes such as sugar cane residue, recycling rejects and commercial food waste.