Energy from waste and a circular economy

Food scraps sent to the waste-to-energy plant at Wollert, in Melbourne's north, feed a hungry beast.

The plant owned and run by Yarra Valley Water can process up to 33,000 tonnes of food waste every year, enough to power about 2,000 homes.

The process begins when food waste is delivered from airlines, commercial suppliers and the nearby Melbourne Wholesale Fruit and Vegetable Market.

The waste is scooped up and fed into the mouth of the machinery, where it's chewed into smaller pieces and piped into giant tanks.

"It just works exactly like a stomach," says Yarra Valley Water's managing director, Pat McCafferty.

"What we're basically doing here is converting food waste to renewable energy using the gas that's produced when you starve the waste of oxygen."

The gas is burned off to power two turbines, generating enough electricity to power the neighbouring water treatment plant.

About 70 per cent of the power generated is fed back into the grid, and Mr McCafferty says the process creates about a twentieth of the amount of methane that it would in landfill.

"In Victoria we're producing over two million tonnes of food waste per annum so there's a hell of a lot more that can be used," he says.

"We're planning a second plant ourselves and there's definitely a lot more scope."

Waste to green energy? It's complicated

Waste-to-energy is in its infancy in Victoria relative to the rest of the world, but there are about 20 small-scale plants in operation and proposals to build more.

The Yarra Valley Water plant uses an anaerobic digestive model, but others would incinerate or create gas from household rubbish.

China's ban on low-grade recyclables has sent governments and industry scrambling for solutions, and then-environment minister Josh Frydenberg championed waste-to-energy as one option.

But apart from taking several years to build, environment groups are concerned building large-scale waste-to-energy plants would embed a reliance on generating waste as fuel.

Nick Aberle from Environment Victoria said waste-to-energy was a complicated question.

"It's not a simple 'yes or no waste-to-energy is good, waste-to-energy is bad', it really depends on individual circumstances for each proposed plant," he says.

Even a plant relying on food waste has its issues, he says.

"One of the questions that we would have is [is] this actually the best use for our food scraps? We know that organics can be converted into compost which acts as a fertiliser so that is potentially a better option."

But when it comes to burning household rubbish, Dr Aberle has concerns it would undermine recycling while damaging the environment.

"The more plastic you're burning you're basically running a fossil-fuelled power station which is what we're trying to get away from."

Waste-to-energy the only operation at scale

The Wyndham City Council, in Melbourne's west, recently agreed on planning permissions for a new waste-to-energy plant at Laverton North that would process 600 tonnes of residual household waste.

The council's director of city operations Stephen Thorpe says it is one of the few that still operates its own waste services and is looking to move away from reliance on landfill.

He recently took part in a tour of waste facilities in Europe, where he saw waste-to-energy in action.

"In the long run as an alternative to landfill it was the only thing we saw operating at scale in Europe," he said.

The Victorian Government was developing a policy on waste-to-energy, releasing a discussion paper canvassing the issues.

However it has now been shelved while it develops a broader strategy for reducing waste.

Energy and Environment Minister Lily D'Ambrosio is firm on the issue.

"Waste-to-energy cannot be something that incentivises or encourages the creation of more waste," she says.

"It cannot undermine a focus on developing up a very strong recycling sector.

"The actual production of energy shouldn't be the goal of a waste-to-energy project, it's an important by-product, absolutely… but the first principle of the waste hierarchy is you encourage people to create less waste."

Mr Thorpe from the Wyndham City Council agrees.

"At the end of the day the amount of material going into landfill or waste-to-energy is materials lost, so the more people can do to minimise the amount the better," he says.

However he says Victoria should adopt similar policy positions to those in Europe, diverting waste from landfill and taxing what does end up at the tip.

"Because every option that's available as an alternative to landfill [in Australia] is more expensive."

Creating a circular economy

The Victorian Government is due to finalise a circular economy policy by 2020 — a series of actions to reduce how much waste goes into landfill, encourage recycling and recycling-based manufacturing.

But businesses like Close the Loop in Melbourne's north are already in action.

Close the Loop collects printer toner cartridges and soft plastics, working with construction company Downer to create a road surface built from recyclables.

Close the Loop's Peter Tamblyn says for the circular economy to work, customers need to purchase recycled products.

"We need those end markets, if we don't have end markets we don't have a circular economy, it's as simple as that," he says.

"We're facing a waste crisis, we've got a solution that is part of the answer to that waste crisis, particularly around soft plastics.

"The challenges are shifting the thinking to innovation, shifting the thinking from just purchasing a road to purchasing a road but also solving a waste crisis… we're not the answer but we're part of the answer."

Rethinking the use of "stuff"

According to Jenni Downes from the Institute for Sustainable Futures at the University of Technology Sydney, the circular economy is about more than recycling.

She points to car share schemes as an example of the principles in action.

"Instead of owning things we might borrow or share them, products are designed to be shareable," she says.

She says despite kerbside recycling collections across the country, Australia has not been a big recycler.

"What we think of recycling here in Australia is actually sorting, so we collect material and sort it into different streams and then we look for other people to recycle it and send it off overseas," Ms Downes said.

"And that's something that the China ban has really highlighted and made it clear that that's one of the things to progress towards a circular economy that we need to be doing here in Australia is actually using that material in our own products."

Environment Minister Lily D'Ambrosio says the Government has changed its procurement policies to encourage consumption of recycled products.

She says they have also injected more funds into the recycling sector to help them adjust to China's policy.

"There's more to do, absolutely there is more to do," she says.

"And that is why a circular economy policy will be an all-encompassing set of policies, objectives and actions."

While the recycling crisis means governments are struggling to cope with plastics in the short term, Ms D'Ambrosio insists it should not undermine confidence in the system.

"Victorians have always wanted to do the right thing by our environment and they are always looking for opportunities to do more. And we encourage Victorians to keep recycling, keep separating out your household rubbish."

ABC article