Biochar remains promising

A recent commenter on Hot Topic made critical reference to biochar, providing links to publications from Biofuelwatch. Since I have written posts in the past highlighting the favourable possibilities which biochar may offer I thought it was perhaps time to revisit the matter. Biofuelwatch is an organisation which works “to raise awareness of the negative impacts of industrial biofuels and bioenergy on biodiversity, human rights, food sovereignty and climate change”.  It has recently published a report Biochar: A Critical Review of Science and Policy which sets out its disagreement with the claims of biochar advocates.

First, on the claim that biochar can act as a means of sequestering carbon over a long period, the review agrees that it is clear that charcoal can in some cases be stable over long periods, but adds that it is also clear that this is not always the case, and that the reasons for this variability are not well understood or controllable.

To the claim that biochar increases soil fertility the review responds that studies of soil fertility effects to date are all short term and therefore do not represent the impacts over time. It therefore objects to the promotion of biochar as a technology for improving the livelihoods of subsistence farmers in the developing world.

Overall the review accuses the biochar advocates of hype unsupported by scientific research or experience on the ground.

Biofuelwatch is clearly concerned that looming behind the advocacy of biochar on a large scale may be the spectre of forest monocultures and corresponding threats to biodiversity. That’s a proper concern, and it has already become apparent in the area of biofuels and bioenergy that some practices and proposals are unsustainable.

I certainly felt dismay when I read in the review that the only multinational so far lending support to biochar is ConocoPhillips and their main interest appears to be in a new source of carbon offsets for their tar sands investments in Canada. That’s not my interest. The attraction of carbon capture through biochar is that it might be a technology which enables us to pull down the current level of atmospheric CO2, not one that seemingly allows exploitation of fossil fuels to continue unabated.

However, it was difficult to understand why Biofuelwatch was so insistently negative about biochar’s possibilities, and there was a notable lack of specific reference to back up their objections. Even a company like World Stove, which makes pyrolysis stoves for the developing world, producing gas and leaving a residue of biochar, is criticised.

I had a look at World Stove’s response to the Biofuelwatch review and, seeking somewhere to start in a single post on a complex and contentious issue, thought I’d report some of what they have to say in their very reasonable eight-page statement.  They are somewhat bemused at the criticisms handed out by Biofuelwatch since they consider their stoves are intended “to empower small farmers, increase food sovereignty, and decrease forestation, thereby preserving ecosystems and mitigating climate change”, aims very much in sympathy with what Biofuelwatch stands for.

Some 20 percent of the small waste biomass used to power the pyrolytic stoves is converted to biochar, and in this respect World Stove claims their process is actually carbon negative in leaving a residue which can be sequestered in the soil.

One of the criticisms levelled at them is that the amount of biochar produced is inadequate for the purpose of increasing crop yields, which needs to be at the rate of 20 tonnes per hectare to be effective. World Stove’s reply is that the common agricultural practice of side dressing allows even small amounts of char to achieve the high concentrations that are acknowledged as being beneficial to plants and soil.

The question of whether there is sufficient waste matter to supply biochar manufacture on a large scale is frequently raised, and it appears in Biofuelwatch’s criticism. World Stove has an impressive array of figures in response, of which I’ll mention only a few here. They quote one study which estimates that just 30 percent of crop waste from five major crops would provide 600 million tons of residue safely available for charring without reducing soil fertility or increasing danger of erosion.  Another study reports that in Egypt alone 20 million tons of rice straw are burned annually for disposal. Food waste is of enormous proportions; in the US alone it has been calculated to be the energetic equivalent of annual extraction from oil and gas reserves off the nation’s coastlines. All this is part of the biomass resource which can be accessed immediately, and World Stove repeats that biomass processing with a balance of energy and char products is the only method of producing energy that is potentially carbon negative.

Finally, World Stove offers some explanations to those presuming that small stoves in developing countries can hardly make much difference to the climate challenge the world is facing. The figures surprised me. People in developing nations have been calculated to use between 0.36 and 1.4 metric tons of wood, per capita, per year, for cooking and heating. The lower of these equates to emissions of 1,650,150,000 metric tons of CO2 per year from all traditional cooking stoves and open cook fires. Changing open burning to pyrolysis stoves would save that carbon already sequestered in trees. Using waste biomass for pyrolysis stove fuel would sequester another 265,530,000 metric tons of CO2 per year. A combination of the two values gives a total of 1,917,680,000 metric tons of CO2 saved per year by not harvesting trees and by creating biochar from waste biomass. That’s the equivalent of nearly two Pacala/Socolow wedges. For comparison, this would be similar to adding four times the current nuclear capacity to replace coal-burning power plants worldwide.  Of course, changing open burning to pyrolizing stoves throughout the developing world would be difficult, but on these figures it’s well worth attempting.

No doubt biochar can be over-hyped.  But I wouldn’t have thought that was the case with World Stove. Nor is it the case with the painstaking research being conducted in many centres in many countries. One of those is the New Zealand Biochar Research Centre at Massey University. An excellent Our Changing World programme on radio NZ gives a good idea of the range of the detailed research being undertaken there, and along the way outlines the issues associated with both the carbon sequestration and the soil enrichment aspects of biochar.  Well worth half an hour of listening time. It still looks a promising technology to me.

11 thoughts on “Biochar remains promising”

  1. I think the key problem of hype around biochar is its promotion as some kind of panacea. There may well be a role and pyrolysis stoves offer some other benefits (air quality and fuel security) but take care with ‘US food waste’ and ‘Egypt’s rice straw’ – Returning food waste to land as compost may be a better environmental outcome than pyrolysis and biochar, and US food waste has to be minimised. Likewise, there may be better ways to return rice straw to land (direct, farmyard manure, composted with other wastes) than as biochar.
    I don’t know of any results yet of comparative lifecycle assessments, and more importantly, the long term assessments of biochar returns on C sequestration and soil functional capacity for key land use systems.
    I do hope that the promise manifests to offer a marginal improvement over current (underutilised/squandered) opportunities in some circumstances. Realistically that is the best that I think we can hope for from biochar.

  2. “Returning food waste to land as compost may be a better environmental outcome than pyrolysis and biochar…”

    Here, here. If people want to read a really good synopsis of sustainable agriculture, then check out “Dirt: the erosion of civilizations, by David R. Montgomery”. A very important component is maintaining a good depth of organic matter in topsoil, and the farming techniques that best achieve this. Note that the carbon cycle is a small part of the story. Retaining nutrients/moisture, preventing erosion is another important part and can mean reducing the need for fertiliser and irrigation. Note also that there is scope to store carbon in soil as organic matter, if it is farmed appropriately. The Montgomery book covers ancient civilizations that have withstood the test of time and those that collapsed due to land mismanagement. I would strongly advocate that we follow the principles of those that survived, rather than shooting for the technofix option that attempts to address only a small part of the problem.

  3. Both the Organic and Agricultural chemical schools of soil science recognize Biochar as a powerful tool to
    foster biodiversity and nitrogen efficiency in soils.

    Recent work by C. Steiner, at U of GA, showing a 52% reduction of NH3 loss when char is used as a composting accelerator. This will have profound value added consequences for the commercial composting industry by reduction of their GHG emissions and the sale of compost as an organic nitrogen fertilizer.

    The Paleoclimate Record shows agricultural-geo-engineering is responsible for 2/3rds of our excess greenhouse gases. The unintended consequence, the flowering of our civilization. Our science has now realized these consequences and has developed a more encompassing wisdom. Wise land management, afforestation and the thermal conversion of biomass can build back our soil carbon. Pyrolysis, Gasification and Hydro-Thermal Carbonization are known biofuel technologies, What is new are the concomitant benefits of biochars for Soil Carbon Sequestration; building soil biodiversity & nitrogen efficiency, for in situ remediation of toxic agents, and, as a feed supplement cutting the carbon foot print of livestock. Modern systems are closed-loop with no significant emissions. The general life cycle analysis is: every 1 ton of biomass yields 1/3 ton Biochar equal to 1 ton CO2e, plus biofuels equal to 1MWh exported electricity, so each energy cycle is 1/3 carbon negative.

    Beyond Rectifying the Carbon Cycle;
    Biochar systems Integrate nutrient management, serving the same healing function for the Nitrogen and Phosphorous Cycles. A 50% reduction of NH3 loss when composting. Ag manure char absorbs phosphorus for nutrient credit income, CHP, Biomass Crop & energy grants and when carbon comes to account, another big credit. The compounding soil benefits; reduced nitrogen loss & soil Nitrous-oxide
    emissions and a 17% increased water efficiency are documented in trials across soil types and climates. The production of ammonia and char from biomass and other third generation companies aiming for drop-in fuels, can free agriculture from fossil energy.

  4. This link offers a thorough discussion regarding the issues surrounding biochar:

    What seems apparent is that biochar may be a can of worms, much like the GE crop panacea. When attempting to introduce a new technology to solve a problem, you run the risk of creating new problems. This seems to be the human way. We don’t like adopting traditional methods that we know have worked for thousands of years. We embark into the great unknowns.

    My biggest concern is that considerable land use will be dedicated to biochar production, when we should be aiming to increase permanent forest sinks, which are far better in promoting biodiversity, and improving the health of dying ecosystems.

    Biodiversity is critical as indicated here:

  5. econexus. is criticizing from the first academic book, they totally avoid the facts that small clean gasification & pyrolitic cook stoves, that can take any biomass & produce char, have such low emissions that the use at scale replacing open fire cooking would equal the eradication of Aids & malaria combined

    They are voicing concerns on the “black
    box” nature of biochar effects. My reviews of the field trials & literature
    clearly show consistent positive effects in temperate & tropical soils, what is not known, and in debate, are the mechanisms, particularly the enhancing effects on sorbtion & binding when soil biology is added to the mix.
    DuPont’s work exemplified this, their lab bench results showed good binding
    but did not hit 95% reductions in food web uptake until the in situ study
    with the full complement of microbes, fungi and the bioturbations’ of macro fauna. The majority of soil wee-beasties are not characterized and only now can be studied with current techniques like meta-Genomic assays, because most can not be cultured individually outside their symbiotic environments.

    This same problem remains for explanation of the mechanisms of other char applications, The internal biology changes when char is used as a feed ration for live stock, The role of Phosphorous chars for both plant
    availability and an heavy metal binding remediation techniques. The
    intricacies of fostering increased aerobic conditions into deeper soil
    horizons, I’m just so glad we have all these positive affects that tantalize
    researchers and will build funding support to answer the mechanism
    What the CFC/Ozone success story was for raising the importance atmospheric
    chemistry, I feel biochar will be for carbon soil chemistry, Mycology and

    The Ozzie’s for 6 years now in field studies
    The future of biochar – Project Rainbow Bee Eater

    The Japanese have been at it decades:
    Japan Biochar Association ;

    UK Biochar Research Centre

    ICHAR, the Italian Biochar Association

    Virginia Tech is in their 6 th year with the Carbon Char Group’s “CharGrow” formulated bagged product. An idea whose time has come | Carbon Char Group
    The 2008 trials at Virginia Tech showed a 46% increase in yield of tomato transplants grown with just 2 – 5 cups (2 – 5%) “CharGrow” per cubic foot of growing medium.

    USDA in their 3 nd year by Dr. Jeff Novak at ARS
    There are dozens soil researchers on the subject now at USDA-ARS.
    and many studies at The ASA-CSSA-SSSA joint meeting;

    Nikolaus has been at it 4 years. Nikolaus Foidl,
    His current work with aspirin is Amazing in Maize, 250% yield gains, 15 cobs per plant;

    My 09 field trials with the Rodale Institute & JMU ;
    Alterna Biocarbon and Cowboy Charcoal Virginia field trials ’09

  6. Dear Tony,
    Your concerns are addressed in the links I will post, but the short answers I take One at a time;
    “What seems apparent is that biochar may be a can of worms,”
    YES, a very Good can of worms, worms seek it out in the compost pile, worms take char down to deeper horizons, internally & by bioturbation. My field test showed a 25% increase year 1, a doubling of worms in year 2, Worms profoundly destroyed the eastern forest ecology, as we did, when they invaded in 1607. we took the tops, they took the duff down, then we mined it for our crops. Char carbon sequestration is reverse soil carbon mining.

    “much like the GE crop panacea.”
    As you observe, new systems to overcome the limits to growth create new problems. Biochar soil research is addressing many of these problems. Particularly toxc agents.

    ” We embark into the great unknowns.”
    Always have , Always will, Like the great unknown of the Ag revolution 10 thousand years ago.

    “My biggest concern is that considerable land use will be dedicated to biochar production,”
    Biomass should never be burnt, instead it should be fractionated to it’s high value uses.

    “when we should be aiming to increase permanent forest sinks, which are far better in promoting biodiversity, and improving the health of dying ecosystems.”
    Biochar can even accelerate Dr. Hansen’s new plan for 100 GtC of afforestation, through utilizing this substantial new addition to today’s land-based NPP of about 60 GtC/yr and Biochar allows the soil food web to build much more recalcitrant organic carbon, (living biomass & Glomalins) in addition to the carbon in the biochar.
    “The Case for Young People and Nature: A Path to a Healthy, Natural, Prosperous Future”.

    Biochar Soils enable Husbandry of whole new Orders & Kingdoms of life as allies to save the Biosphere!

    “Biodiversity is critical as indicated here:”
    YES!, That is why biochar systems are endorsed by NASA’s Dr. Jim Hansen, and Gaia’s own Dr. James Lovelock,
    Nobel laureates; Al Gore and Dr. Mario Molina, (CFC/Ozone)
    Politicians; Tony Blair, Tony Abbott, Secretaries Salazar & Vilsack,
    Environmentalist; Tim Flannery, Bill McKibben, Richard Branson & his Carbon War Room.
    Both the Organic and Agricultural chemical schools of soil science recognize Biochar as a powerful tool to foster biodiversity and nitrogen efficiency in soils;
    Dr. Elain Engham of the “Soil Food Web” & Head Scientist at Rodale,
    The most cited soil scientist in the world, Dr. Rattan Lal at OSU,

    Dr. Lal was impressed with this talk, given to the EPA chiefs of North America, commending me on conceptualizing & articulating the concept.
    The Talk is Titled;
    The Establishment of Soil Carbon as the Universal Measure of Sustainability
    A Report on my talk at Commission for Environmental Cooperation, and complete text & links are here:

  7. Thanks Erich.

    This is what James Hansen says about biochar:

    He is adamant that it is not the panacea required to overturn climate change. It may have some application, but touting it as any more than that would be over-hyping it.

    Secondly, there are a lot of better options to biochar, and you will just have to watch this space.

    Prof. Lal is an advocate of building soil stocks, but I think you will find that all his published work deals with organic carbon not biochar. Show me the link where Lal thinks biochar is better than organic carbon for building soil stocks.

  8. Organic carbon and Biochar are synergistic, this is the reason Dr. Lal lauded my talk, thanking & commending me,
    The responses from USDA & DOE were also as gratifying.

    Returning from the Montreal event, reflecting on the talk, given all the dire news coming from the oceanographer community, I should have opened the talk with the list of endorsements. Dr. Lovelock’s “ONLY hope for mankind”, now supported by Dr. Jim Hansen’s work and since so many Molina Center representatives were there at CEC, gone strait into Dr. Molina’s Nobel work. How the ozone story has been the most powerful success story of science saving the world from ecological disaster, adding, how his current PNAS report will now do the same concerning carbon.

    Yes, there are no Panaceas, char systems are however a solid carbon wedge, much more needed now if the Germans follow through with a nuke stand down.

    My hope is to wed the best Ag practices & technical pathways for both the organic and agricultural chemical schools of soil science. Both recognize Biochar as a powerful tool to foster biodiversity and nitrogen efficiency in soils.
    Biochar effects on soil biota – A review
    Soil Biology and Biochemistry journal, a review of international work by Lehmann & Janice Thies;

    FAO on Conservation Agricultural:
    “In general, soil carbon sequestration during the first decade of adoption of best conservation agricultural practices is 1.8 tons CO2 per hectare per year. On 5 billion hectares of agricultural land, this could represent one-third of the current annual global emission of CO2 from the burning of fossil fuels (i.e., 27 Pg CO2 per year).”

    Adding just 1 Ton of Biochar per hectare, (800 lbs / acre), would cover 100% Current Annual Fossil CO2 Emissions.

    “Greenhouse Gas Mitigation Potential of Agricultural Land Management in the United States: A Synthesis of the Literature”
    An extensive scientific literature review providing a side-by-side comparison of the biophysical greenhouse gas (GHG) mitigation potential of more than 40 agricultural land management activities in the United States.

    The IBI now has 33 biochar affiliates around the world — including in China, India, Japan UK, US, Australia, Korea, Canada, Italy and Israel.
    Note also that our Japanese colleagues in the Japan Biochar Association have a very long tradition of biochar use and have been developing “modern methods” over the last thirty years. A governmental act officially acknowledged charcoal as a “soil ameliorator” back in 1988 and have completed work using Biochar as an in situ sorbent of Cd, and starting work on heavy metal radionuclides.

  9. “Adding just 1 Ton of Biochar per hectare, (800 lbs / acre), would cover 100%
    Current Annual Fossil CO2 Emissions.”

    OK where will you derive the biomass to cover 5 billion hectares with biochar?

    The link you provide doesn’t suggest that biochar increases soil biodiversity only that a lot more research will be needed to determine the effects. The only studies I know of are on earthworms and in controlled environments.

  10. Erich,

    One more question. How much biochar can you add to soil before you are well into overloading the system? If you add 1 ton per hectare, is that as far as it goes, or can you add more after that, assuming that there is ample research showing no adverse effects on soil biota. Also, in arid/semi-arid regions, how do you ensure that the char doesn’t get blown away in a strong wind.

  11. RE: overload
    “Surprisingly, after one year and after two years, soil carbon levels were higher in the “control” plots (no biochar added) than in the plots to which 20 tons/ha of biochar had been added.” – ‘First medium-term, peer-reviewed biochar field trial | What happened to all the carbon?’ :

    RE: where will you derive the biomass to cover 5 billion hectares with biochar?
    Well, in Nature, the International Biochar initiative, the world’s main Biochar lobby group / network has suggested that an area one and a half times the size of India should be put aside for biochar production globally.

    Here is Friends of the Earth Australia’s briefing on biochar :

    Heres ETC group’s communications on Biochar ;

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