Biochar: untested and unproven — or political football?

Tuesday, 24 February, 2009


The global warming challenges we face have been linked to our addiction to digging 'black stuff' out of the ground and using it to fuel our growth and prosperity. Biochar technology offers society the opportunity to pay back this historic greenhouse burden — by taking renewable resources, converting them into 'black stuff', or biochar, which can be beneficially sequestered in the ground. The good news is that biochar sequestration actually adds value by increasing soil productivity, so it can contribute to ongoing prosperity rather than coming at a huge cost to society.

The Federal Minister for Agriculture, Fisheries and Forestry, Tony Burke, stated: “There are many different technologies that can be used to try to deliver [carbon sequestration in soil] and biochar is one of them. It’s untested, it’s unproven.” He expressed that the opposition party’s enthusiastic support of the technology is “a long way in advance of where the scientists are at”.

The fundamental premise of the stability of charcoal in the environment is well established in many scientific disciplines. For example, archaeologists routinely use carbon dating of charcoal created tens of thousand of years ago.

So what is the view of prominent scientists on biochar’s potential as a climate solution? Professor James Hansen, Climatologist and head of the NASA Goddard Institute for Space Studies, has published in a peer-reviewed scientific journal that “Biochar […] can be used to restore soil fertility while storing carbon for centuries to millennia […] [and] could provide a CO2 drawdown.”

Veteran environmentalist and accomplished chemist Professor James Lovelock, when interviewed for New Scientist on solutions for our time, concluded: “There is one way we could save ourselves and that is through the massive burial of charcoal.”

In the Ecopolis documentary made for 'Discovery Channel', Daniel Kammen, Nobel Prize-winning Professor of Energy at the University of California, Berkeley, concluded: “Finding places to store carbon — to sequester it — is a rare commodity that pushes biochar into the lead and makes it a clear winner.”

In Australia, Evelyn Krull, soil carbon expert at Commonwealth Scientific and Industrial Research Organisation (CSIRO), says: “Biochar technology is a research priority for us because it can be an opportunity for Australia to help mitigate carbon emissions and assist agriculture to combat decline in soil health.”

Professor Tim Flannery, environmental scientist and Australian of the Year 2007, has been a champion of biochar technology for several years. Flannery has said: “I think this is one of the most exciting and important new technologies out there, in terms of stabilising our climate,” and that “it does seem to look too good to be true but I've looked at it from every angle and I fail to see the fault in the system”.

On the ground, NSW Department of Primary Industries (DPI) has been conducting biochar trials for Australian agricultural systems since 2006. This work has been assisted by the supportive NSW state government. Senior Scientist Dr Lukas van Zwieten says: “We have scientifically demonstrated that biochar products can increase soil carbon levels, offering an opportunity to restore the carbon levels of Australia’s depleted soils. Our trials have also shown improvements in crop productivity and soil health, which is obviously a win-win situation for farmers.”

The challenge facing researchers in Australia is that the proposed exclusion of biochar carbon sequestration from the government's Carbon Pollution Reduction Scheme (CPRS) means there is no incentive for the industry investment required to establish the demonstration biochar production facilities that are necessary to measure and verify the actual greenhouse balance across the process and have enough biochar for large-scale, scientifically verified studies.

The biochar process has several advantages in terms of greenhouse accounting. As a controlled and engineered production process the monitoring and verification required for greenhouse accounting is straight forward compared with other accounting challenges such as growing trees. Professor Johannes Lehmann of Cornell University published in Nature: “Biochar is a lower-risk strategy than other sequestration options, in which stored carbon can be released, say, by forest fires, by converting no-tillage back to conventional tillage, or by leaks from geological carbon storage.” Lehmann has done extensive work on the Terra preta soils of South America that provide a biochar sequestration case study set up by pre-Columbian Indians centuries ago.

The technology required for the large-scale production of biochar is far from unproven. The production of charcoal is in fact one of the oldest industrial processes. Traditional charcoal making, however, does not usually include energy recovery and therefore does not have a promising greenhouse balance. Biomass gasifiers, for the production of renewable energy, have also been in commercial operation for decades and can be used for biochar production. Their traditional focus on energy production via a gaseous fuel (syngas) results in only a mineral ash remaining in the solid form, with little stabilised carbon or char. The greenhouse challenge has brought the attention of engineers to optimising the co-production of charcoal and bioenergy, in effect incorporating these two concepts to provide a true climate change solution.

Proof of concept of the technology has been achieved in Australia, with  Best Energies Australia and NSW DPI winning the 2007 United Nations Association of Australia (UNAA) World Environment Day Prize for this achievement. Best Energies has a pilot plant in NSW which has successfully produced biochar and ‘carbon-negative’ green electricity from a range of waste organic material. It has designs for commercial systems and could start construction tomorrow given the required investment.

Inclusion of the technology as an option for greenhouse gas mitigation in the CPRS will ensure that the technology is subject to the accreditation and auditing regulations and any offsets generated are verified.

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