The world wastes around a third of all food produced each year.
In Australia, this equates to more than 7 million tonnes of edible food and is estimated to cost the economy more than $36 billion annually, according to a report commissioned by the federal government.
At the same time, many of us cook with gas, which is increasingly expensive and contributes to greenhouse gas pollution.
But there is a growing movement of people and companies looking to kill two birds with one stone.
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Creating biogas at home from food waste, which can then be used for cooking, is getting easier.
Some companies now offer larger-scale systems for restaurants and even refugee camps, as well as basic home installations.
About six years ago, Annett and Paul left city life in Sydney and moved to northern New South Wales, where they built a tiny house off the grid.
As part of this setup, they installed a biogas food digester that feeds food scraps and toilet waste.
From this organic material, the system produces methane, which is fed through a line to a gas stove in your home.
Annett says there are some days in the summer when the system is more productive and they struggle to keep up with the amount of gas they generate, which they use to subsidize their solar-powered electric cooker.
“It’s good. We’re basically using it in the morning or at night when the sun isn’t up,” says Annett.
“We actually have to try to use everything first [the system] fills up.”
Making gas pays for itself
Food waste emissions account for about 3 per cent of Australia’s total greenhouse gas emissions each year, according to data from the former federal government.
Worldwide, it is closer to 8% of emissions.
Ways to reduce the cost of living
While creating biogas at home isn’t a “panacea” for our food-based emissions, it’s a potentially valuable piece of the puzzle, according to the authors of a 2019 Australian study.
In the case study the authors looked at, it also proved to be an economically viable option.
This study found that enough gas was produced from a single household to cook for an average of almost 38 minutes each day.
However, this included some days where no gas was used and others where up to two hours of gas supply was used.
According to their data, a system would pay for itself in just over four years based on savings from gas purchases alone.
And that was based on the lowest gas prices at the time.
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If the fertilizer savings, which is a byproduct of methane creation from food waste, were also taken into account, this payback time would again be shorter.
Like Annett and Paul, Ned lives on an off-grid property near the Hawkesbury River in New South Wales and creates his own biogas.
“It’s probably been about six months now [since we got the system].
“The bladder where the gas is stored lasts about two and a half hours.”
He says he realized the true usefulness of making his own biogas when his family was recently flooded.
“[The delivery driver] he couldn’t get in to deliver a bottle of gas,” he says.
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“This whole idea that you can always go to the store and get stuff … it’s not always like that.”
He says his system doesn’t produce enough gas to cover all of his cooking needs, but it’s great for backup and diverting waste from landfills.
“We probably don’t have as much food waste as [the average family].
“We are a family of five, three young children, the amount of gas cooking we do is probably more than we could generate from purely residential food waste consumption.
“[But] if it’s a few days between uses, it’s a great backup because it’s reliable and it stores.”
Annett says it’s a similar case with her family’s system.
At first, they went to farmers markets to get extra food scraps to feed them, but now they just use gas as a back-up.
“We’re not feeding it as much as we could, you could feed it up to six litres [of food waste]per day, but we only add one or two.
“If you’re just using it to make coffee or tea, you can use it every day, but if you’re preparing food…we have to keep a little watch on it.”
Read more about Australia’s energy crisis:
What if I live in an apartment?
There are other requirements for creating biogas at home as well that make it not a viable option for everyone.
While there are a number of different systems, and some people even make their own custom versions, they all take up quite a bit of space and probably aren’t conducive to apartment living.
This is because, unlike the liquefied natural gas we get in gas bottles, for example, methane produced from food scraps remains in its expanded gaseous form.
Ned is quite practical and is looking for ways to compress homemade methane, but for others this would not be an option.
Another problem is the temperature.
Anaerobic digestion stops below 20 degrees Celsius and has an optimum digestion temperature of about 35 degrees Celsius.
While an electric heating device is an option to maintain production in cold climates, Annett says his system slows down significantly this time of year.
“Right now it’s winter and it’s not as warm as it should be. It’s not as productive as it is in the summer.”
So are there solutions for people without space or in colder climates?
Byron Bay could soon have a large-scale biogas facility fueled by household and commercial food waste. (Provided by Bioenergy Australia)
Western Australia’s City of Cockburn Council has run a trial where they are collecting food waste from partners such as fish and chip shops and bakeries.
They are then delivering this waste to a fertilizer plant where the methane is captured and used to power generators to produce electricity.
At their peak, they estimate that the generators are supplying electricity from biogas to around 3,000 homes.
And while Cockburn’s is just a trial, Byron Shire is looking to implement a similar program on a permanent basis.
Byron already has a three-bin system, with one dedicated to food waste that the green community is behind, according to bioenergy project manager John Hart.
“There’s been a very strong turnout from the residential base up here.”
With this waste collection system already up and running, he says he hopes to see his biogas generator up and running soon.
“We would like to start around February 2023 after the summer holidays and have the facility up and running a year later,” he says.
In addition to being a cheaper alternative to landfill for businesses, Hart thinks that with rising fuel and waste disposal costs, the savings could trickle back down to taxpayers.
“The business case for this facility is that we’re going to keep it local. We’re going to reduce lorry movements and feed green electricity into the council’s biggest treatment plant.
“It makes sense that residential rates will come down, which will be a huge success story for the local residential ratepayer.”
Read more about the cost of living:
A waste treatment solution for refugee camps
Internationally, a company called HomeBiogas is making a system it says can work in apartment buildings and will plug into the sink’s garbage disposal channel.
It is also launching a system targeting restaurants and army bases, and has been supplying refugee camps with systems to help manage food and toilet waste.
“HomeBiogas is supplying biogas systems for the treatment of organic waste to refugee camps in Africa, after winning two UN tenders,” says CEO Oshik Efrati.
Founded by a trio of marine biologists, the company says it has deployed more than 15,000 systems to date, offsetting more than 76,000 tons of CO2 emissions worldwide by 2021.
Mr. Efrati expects these numbers to increase significantly in the coming years as larger products come online.
“Each commercial system can reduce greenhouse gas emissions by up to 1,000 tonnes of CO2 equivalent per year, compared to six tonnes per year for domestic systems.”
He says producing biogas at source is part of a global movement to rethink “waste” as a resource.
“Countries around the world are starting to understand this and have implemented regulations that prohibit sending waste to landfills,” he says.
“We have no other choice, as landfills are filling up and their methane emissions are particularly harmful to the environment.”
The UN and the International Energy Agency agree.
They have estimated that biogas could supply up to 20 percent of our gas demand as we move away from fossil fuels.
Ned says it’s a no-brainer.
“The fact that it can take all the food waste and process it on site … on a community and global level, if people weren’t putting food waste in landfill, that would be huge.”
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