Just outside a blink-and-you’ll-miss-it-town about three hours’ drive north-west of Melbourne at Kia-Ora Piggery, brothers Jarad and Caleb Smith are turning pig poo into power.

If this isn’t unconventional enough, they are using 12 pre-loved Ford Falcon engines to do it.

Seven years ago their father Tom, with his mate Brendan Mason, set out to design an “industry orientated” biogas test system specifically for smaller piggeries. Substituting second-hand car engines for new generators, they created an innovative, one-of-a-kind biogas system that turns pig waste into energy.

While the Smith family’s wrangling of the technology may be unusual, they are far from alone in going down this path.

Piggeries across the country are looking for innovative solutions to their waste and odour problems, along the way reducing their carbon footprint and saving on power bills.

As industry and governments move to haul back rising greenhouse gas emissions, experts anticipate that converting waste to power could become a crucial part of Australia’s transition to renewables in the agricultural sector. Some expect it could also provide some solutions for the national waste crisis, but if it’s going to realise this potential, it’s got a few hurdles to overcome yet.

The first is around the technology. Though the system at work on the Smith brothers’ farm is not particularly sophisticated, getting it right can be tricky.

Pig effluent is pumped into a deep dam that is covered and sealed by a plastic cover. In this anaerobic (oxygen free) environment, naturally occurring bacteria breaks down the effluent, releasing a mixture of gases – primarily methane, some carbon dioxide and small portions of other gases such as hydrogen sulphide.

The captured gas is then filtered to remove the hydrogen sulphide, and is either flared or burned through a generator to make electricity.

After a bumpy start, Kia-Ora’s system now collects 120,000 tonnes of pig manure annually. This has resulted in an 81 per cent reduction in greenhouse gas emissions at the site from 16,598 tonnes a year to 3121 tonnes a year. It has also meant a saving of more than $100,000 on the Smiths’ annual power bill.

The implications of applying this kind of technology on a broader scale in agriculture are huge. Globally, the livestock industry is believed to contribute about 14 per cent of human-related greenhouse gas emissions.

Progress on hauling this down is beginning to be made as farmers realise the need to clean up their act. Last year, Meat and Livestock Australia (MLA) told the ABC that a national zero carbon footprint was possible by 2030 through a combination of planting trees, using different feed and biogas solutions.

While biogas technology has been implemented on some dairy and poultry farms, there’s been particular momentum in the pig industry.  Jared Smith believes this is because piggery owners tend to be progressive in their practices, and are becoming “better educated on ways to improve their systems to work with the environment.

“It’s becoming more and more critical for piggeries to make sure they are controlling their environmental impact.”

Biogas technology makes a lot of sense in an agricultural context, due to the abundance of biological feedstock – in other words, poo. On top of that, the heat that is produced as a byproduct of the process has a variety of uses back on the farm.

At Kia-Ora, the heat is used to warm piglets, helping to significantly reduce the farm’s power bill, which is typically a major portion of expenditure.

Biogas expert Dr Bernadette McCabe, principal scientist at the University of Southern Queensland’s Centre for Agricultural Engineering, also sees great potential for the technology in urban areas where biogas production is almost non-existent.

Given Melbourne is Australia’s fastest growing city, with a population projected to reach 9 million by 2031, there’s an urgent need to improve the management of food waste in urban areas, and McCabe sees an opportunity here rather than a problem.

“I see an untapped potential in food waste,” says McCabe, who is also Australia’s team leader on the International Energy Agency Bioenergy taskforce.

In Victoria, around 55 per cent of kerbside waste sent to landfill is organic material, with around 36 per cent of this being food waste. When this waste gets to landfill, it is broken down by micro-organisms and releases methane, a greenhouse gas which is 25 times more potent than carbon dioxide. Harnessing organic material in cities could be a win-win, reducing gas emissions while also producing a source of renewable energy.

Economist Dr Samuel Alexander, a research fellow of the University of Melbourne’s Sustainable Society Institute, tested out this technology in an experiment in his suburban backyard. Three years ago, in a quest to actively investigate sustainable energy practices, he bought a home biogas unit off the internet for $1000 and was “blown-away” by the results.

After taking meticulous daily data he calculated the averages. A kilogram and a half of organic waste could produce 37.8 minutes of cooking gas each day, usually enough for his household to prepare three meals a day.

“Over a two-year period we’ve put on the electric stovetop maybe a dozen times to supplement cooking when there’s been insufficient biogas,” says Alexander.

Although the compost bin has suffered losses, Alexander is not worried as the unit produces a rich, organic sludge in the process which is a nutrient dense fertiliser he puts on the garden.

“Biogas isn’t a panacea. We’re not going to be able to run all household energy demands on biogas,” he says.

“But if for example most suburban households used biogas to cook on, it would significantly reduce demand firstly for fossil fuels, and secondly it would reduce their demand on the grid at peak times.”

However, McCabe is more cautious about the prospects for backyard operators. She’s concerned about the potential for fugitive emissions – the risk of trapped methane gas escaping into the atmosphere if the system was not functioning correctly.

“I do not want to see a developed country do that when we’ve got so much potential to do something else,” says McCabe. “The better way to go would be if there was a kerbside collection system where you have municipalities collecting food waste which would then go to a centralised anaerobic digester.”

In the ongoing political mire of Australia’s energy policy, the issue that comes up again and again is around the capacity and reliability of renewables to provide baseload power.

According to McCabe, biogas is one of the most reliable of the bunch, something which “doesn’t get enough airplay”.

Biogas has the potential to be used in combination with solar and wind to balance the grid and flatten out peaks and troughs from wind and solar sources, she says.

With terms like “closed-loop” and the “circular economy” becoming buzzwords in the conversation around renewables, the usefulness of biogas seems obvious. And yet while the technology is common and hugely successful in other parts of the world including China, Germany and the United States, Australia – with the exception of agricultural pathfinders like the Smith brothers – has been slow to catch on.

A 2016 report on biogas by the International Energy Agency found that renewable energy provided 14.8 per cent of Australian electricity generation during 2015-16, with biogas contributing to an estimated 10.1 per cent of that renewable generation – just 1.5 per cent of total generation.

But according to a 2019 report by Bioenergy Australia in partnership with the federal government’s Australian Renewable Energy Agency (ARENA), the total estimated biogas potential is equivalent to almost 9 per cent of Australia’s total energy consumption – comparable to Germany’s current biogas production.

It also found the investment opportunities for biogas to be estimated at $3.5 to 5 billion, with the potential to avoid up to 9 million tonnes of CO2 emissions each year.

The biggest obstacle the technology must overcome to realise its potential, says McCabe, is the lack of funding.

Kia-Ora’s Jarad Smith found that getting the technology working was, in many ways, a simpler task than navigating through state regulatory requirements. Cutting through the red tape was “absolutely painful”, he recalls.

But having overcome those hurdles, his poo-powered piggery continues to deliver benefits that he hopes will inspire other farmers to explore their biogas potential.