Chicken poo revolution: Gippsland farmer extracts electricity, dye and fertiliser from waste

Chris Freney is using chicken poo to save a dollar on power.

The Toongabbie poultry farmer is trialling technology he says could help farmers cut their energy bill. It’s known as anaerobic digestion.

“As a chicken farmer, I've always been conscious of our litter, where it goes and what to do with it,” Freney told the Monitor.

Poultry farmers often sell their litter to other growers to be used as fertiliser, but in 2018  Freney hatched a plan to extract more from the 10,000 tonnes of chicken number twos his broiler farm produces every year.

“Essentially, I put the litter into a very big bucket … add warm water … stir it and I put a tarp over the mouth of the bucket,” Freney said. “After 60 days, the digestion period, I get three things out of the bucket - a gas, a liquid and a solid.”

In 2018, he organised a meeting with Wellington Shire Council to discuss the approvals required to operate a system that would turn his litter waste into fertiliser, natural food dye and electricity.

The farmer has since been refining the technology and hopes it will be fully operational by the end of this year.

How does it work?

On broiler farms, chickens live in large sheds bedded with at least five centimetres of litter, usually a combination of sawdust, wood shavings and chopped straw.

During the five to seven weeks the chooks live in the sheds, their feathers, spilled feed and manure collect in the layer of wood and straw.

The dirty litter can be used as a fertiliser, but by processing it through anaerobic digestion, Freney is getting more out of his chicken waste.

What are the bioproducts?

It’s a gas: The gas produced is methane, which Freney can burn using an internal combustion engine. The end result is electricity. He said most of this energy goes to heating his eight chicken sheds.

• Burning biogas methane still produces emissions, but it is considered renewable by the CSIRO because it uses recent organic waste, whereas burning fossil fuels releases ancient trapped methane into the atmosphere.

Freney said the finished system will be able to process 35,000 tonnes of litter (he’s considering purchasing more manure from other farmers) and generate approximately 8MW of electricity - enough to power roughly 1,200 Australian homes.

• He said roughly half of the electricity generated will be enough to power his farm, the other half he’ll sell back to the grid.

The liquid: The second product extracted after the digestion period is liquid. Anything that is water soluble will be absorbed into the warm water Freney stirred into the bucket. 

“The liquid is a high source of nutrients and a very good fertiliser,” he said.

As a bonus, he’s found a lucrative product that can be made from this liquid - natural food dye.

Freney runs the liquid portion into a shallow pond and grows a blue-green algae known as spirulina. 

“We harvest that spirulina and then we sell it as a natural food colourant.”

The solids: The last product to be removed from the bucket is the solid, which is anything non-water soluble.

“It's sludge that can also be used as a fertiliser,” Freney said.

Why start digesting?

Freney has been a chicken farmer since the late 1980s and said he’s always been concerned about his duty of care to the environment.

By processing more of the chicken litter nutrients earlier, Freney said he can avoid some of the impact his fertiliser will have on surrounding rivers and waterways as runoff.

The other driver has been the cost of electricity. 

In 2023, he installed solar panels on his eight broiler sheds, saving him approximately $40,000 a year on energy bills. The anaerobic digester will allow him to cut energy bills and sell electricity back to the grid.

Freney will be sharing his knowledge on a panel at the Gippsland New Energy Conference in Traralgon on August 19.