Credit: BEST Energies
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Plans for large-scale use
These promising observations have prompted scientists to look closely at how biochar could be used in Australia. Both Krull and Cowie say that there's still much research to be done to get the most out of biochar, with the activity of biochar made from different feedstocks and the response of different crops and soil types a particular concern.
However, some growers are already importing biochar from the Philippines, Cowie says, and some Australian government agencies are also showing interest.
Government agencies in New South Wales have already been scouting out suitable sites for commercial-scale pyrolysis plants, Cowie says, and have identified "half a dozen locations" where a plant could be supplied with 50,000 tonnes of biomass a year, the amount of feedstock a commercial plant could burn.
Locating pyrolysis plants close to the biomass supply is important, Cowie says, because transporting the feedstock too far could release more emissions than the biochar sequesters.
"We've determined that a transport distance of maybe a couple of hundred kilometres to such a plant would be reasonable," Cowie said.
Just using material already available, like urban green waste, sawmill residues and crop waste, biochar could cut Australia's greenhouse gas emissions by two per cent, or 11.5 million tonnes of carbon dioxide, Cowie says.
That's equivalent to the annual greenhouse gas emissions generated by 400,000 Australians.
"[Even] using conservative assumptions…biochar does have a substantial greenhouse mitigation benefit," Cowie says.
However, Cowie points out that while two per cent is an important contribution to climate mitigation, biochar can't offset the emissions caused by our current standard of living.
"It's certainly not going to stop us needing to reduce our fossil fuel emissions," she warns.