In a warehouse near the border of Victoria and NSW is a decommissioned machine that sums up how hard it is to find solutions to the climate crisis.
In a warehouse somewhere near the border of Victoria and NSW sits a hulking machine built to fight the climate crisis.
When it ran, it ran perfectly, taking carbon that would have entered the atmosphere and sequestering it in the ground – essentially forever.
Today, it is silent. Decommissioned.
The machines heat material in very low-oxygen environments. Without oxygen, pyrolysis – thermochemical decomposition – is attained instead of combustion. The water and volatile compounds within the wood boil away, chemical bonds break down, and what is left is a relatively unreactive lattice of mostly carbon atoms known as biochar. It looks like dirt or charcoal.
Biochar is an intriguing substance for two reasons. The carbon atoms are baked together into a highly stable structure – think of it as locking the carbon together. It can be buried in the soil and the carbon should stay there, instead of being released into the atmosphere, for thousands of years.
The second attribute is more unexpected and more exciting. Industrial agriculture strips nutrients from the soil, which farmers replace with fertiliser (fertiliser production is responsible for
1 to 2 per cent of global emissions). Biochar’s carbon lattice can hold nutrients in the soil, where they can be slowly released to support plant growth.
While plants respond differently to biochar,
studies of its application show it led to an average increase of 20 per cent in crop yield. Plus, biochar generation can earn high-quality carbon credits, which
traded at $US165 ($257) per metric tonne in 2024.
So why is Campbell’s biochar machine sitting silent?
Balwant Singh, a professor of soil science at the University of Sydney, might be best placed to explain that.
“I have researched almost every aspect of biochar. We have published more than 20 papers on this. I published a book,” he says. “It has very little potential if you consider all the factors and processes.”
The problem, as with many purported climate solutions, is not the final product – biochar seems to work. It is the extraordinary difficulty of building a low-cost, zero-carbon supply chain in a carbon-addicted world.
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Biochar production is enormously energy-intensive. And you need vehicles to gather the waste, distribute the biochar and bury it in the soil. “It all costs energy – and energy is CO2,” says Singh.
To get the price down, you need scale. But different feedstocks – wood, straw, manure, waste food – produce different biochars that are suitable for different soils and crops. There are concerns about contamination.
The federal government has funded two national biochar initiatives. “I was part of both. We finished them seven or eight years ago. If it was a very viable technology, it would have been taken up,” says Singh.
Former climate commissioner Tim Flannery was one of biochar’s strongest early advocates. But as more has become known about the difficulty of scaling the technology up – particularly achieving economies of scale – his enthusiasm has cooled.
“If you’re looking at scalable solutions, it is not ready yet and may not be in the future. It will always have a niche role. But it’s not going to be a scalable solution,” Flannery says.
This is also the problem Campbell’s machine faced: after energy, labor and fuel costs are factored in, his machine is simply too expensive to run. It has become a stranded solution. “The figures don’t add up.”