Disarming the Biochar Wars

peaceSince we posted on the growing debate over biochar, the Internet and the twitterverse have ignited into a firestorm of controversy over biochar. In general, it seems that a lack of information is pervading both sides of the debate. As a seasoned group of biochar enthusiasts, entrepreneurs and researchers, re:char presents the following items which we believe will clear up the most common misconceptions about biochar. We urge our readers to link to this article, as anti-biochar crusaders have resorted to unacceptable tactics such as spamming notable scientists like Dr. James Hansen and Prof. Johannes Lehmann.

Biochar=biofuel: NO. In our research, this is the #1 criticism of the biochar concept, and unfortunately it is very misguided. It stems from the criticisms of 1st-generation biofuels– namely that they use food based feedstocks, have a low or negative energy balance and are generally unsustainable. We agree that 1st-gen biofuels are highly problematic, but to equate them with biochar and pyrolysis is simply not correct.

First of all, the majority of biochar advocates promote the use of agricultural wastes as a feedstock. Ag wastes are NOT FOOD. Instead, they are products that are typically mulched, composted or simply left in-field to rot.

Second, there are many different types of pyrolysis processes and technologies that produce varying quantities of biochar, combustible gas and bio-oil. Slow pyrolysis technologies produce primarily biochar, while fast pyrolysis technologies are designed to produce bio-oil. Bio-oil is not biodiesel nor is it ethanol. It is a hydrocarbon emulsion that can act as a low grade heating oil or bunker fuel substitute. Many groups are working on technologies to refine bio-oil into high-value chemicals or transportation fuels. In general, most fast pyrolysis plants have a parasitic load between 10 and 25%. This means that only 10-25% of the energy produced is used to power the pyrolyzer, making the process highly efficient.

How can burning wood be carbon negative? This issue has come up frequently on the blogosphere as well, and again demonstrates many of the problems that come from misinformation. The skeptics are correct: combustion of wood (burning) is carbon positive. However, biochar is NOT made by burning wood. Biochar is produced via a process called pyrolysis. Pyrolysis is a carbon negative process, meaning upwards of 90% of the CO2 that would be released through combustion is captured as biochar.

Okay but what if you burn the biofuel…. I mean bio-oil? Yes, combustion of bio-oil in an engine, boiler or turbine will release CO2. However, in general these emissions are more than offset by the carbon that is sequestered in the biochar. In addition, bio-oil combustion results in remarkably low emissions of NOx and SOx. Finally, remember that bio-oil is produced from waste which would otherwise decompose completely into CO2 and methane.

Industrial Scale Biochar Production will result in deforestation: UNLIKELY. This is the argument leveled by George Monbiot which has appeared to spark the Biochar Wars. To his credit, Monbiot is correct that industrial scale biochar production could provide an incentive for land-clearing in the developing world. If biochar were accepted under the Clean Development Mechanism as a bankable carbon offset, and if the price of carbon were high enough to justify it, farmers could be incentivized to generate as much biochar as humanly possible.

However, there is a glaring problem with Monbiot’s argument. Currently, there are a handful of companies developing pyrolysis technologies, and a slightly larger handful of scientists who support biochar. Of these two handfuls, we cannot find anyone that is advocating industrial scale biochar. Why? Because everyone in the biochar community already knows it won’t work.

The scientists know that industrial scale biochar production is simply unsustainable. The entrepreneurs know that unless the price of a carbon offset were astronomically huge, there is no way large-scale biochar production would make any economic sense. The cost of transporting a low-value, low-density product like biomass over a distance greater than a couple of kilometers is herculean. This reality is part of what has damned 1st-gen biofuels. The biochar concept works with agricultural waste on the small scale, because these are products that farmers already collect and move to a centralized location for mulching and composting. On the industrial scale, the economics simply don’t work. They never have and they never will.

If, for some reason, the price of carbon did increase 100 fold, it would also allow a host of other dubious offsets to become economically viable. Given that the price of 1 tonne of CO2 currently hovers around $20-30 in Europe, we just don’t see that happening.

Biochar is not a longterm carbon storage mechanism: VISIT THE AMAZON BASIN. There, you will find an intact layer of charcoal in the soil roughly the size of France. Biochar has been shown to be stable in soils for up to 2000 years. That is an order of magnitude longer than any other carbon storage technology.

We hope this article will clear up some of the misinformation surrounding biochar. Obviously, people are weary of any new solution to climate change after the promises of biofuels, wind and solar. Still, let’s not jump to conclusions and make biochar the next betamax. As of yet, it is the only technology that has shown any promise at reducing our concentration of atmospheric CO2. If we ever want to get back below 350 ppm, let’s give biochar a chance.

Ashoka: Innovators for the Public are hosting Tech 4 Society, a conference exploring technology, invention and social change, in Hyderabad, India, in February 2009. Find out more about the conference here. This blog post is an entry in their competition to find the official blogger to travel to and cover the event.

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9 Responses to Disarming the Biochar Wars

  1. Tom G April 8, 2009 at 5:10 pm #

    Biochar is like a piece of meat between the big dogs: Agriculture, Energy, the Environment. Those same dogs are going to be fighting over carbon credits for the next 20 years, so Biochar is going to see some teethmarks. But biochar -the end product- won't power your car or heat your house or put food on your table. The making of biochar will never be as profitable as making fuel directly or food directly, even with carbon subsidies. Besides, you probably will have to bury it before you get paid. That's a lot of work. So I doubt that biochar will be causing the next dystopia.

  2. Kevin Chisholm April 9, 2009 at 9:39 am #

    What would you propose as a definition of "Biochar?"



  3. David Pollard April 13, 2009 at 3:44 am #

    One of the advantages of microwave heating for pyrolysis is said to be that energy is delivered into the bulk of the material, rather than just to one surface of the vessel when external heating is used or to the surface of material chips when hot gas circulation or a transfer medium is used.

    Heating by microwave energy does indeed entail energy loss. If pyrolysis plant can be made at a sufficiently low capital cost, however, there is a possibility to use it at a low duty cycle. Using, say, off-peak nuclear energy the losses are not so much of a concern. The additional capture/recycling of the 20% or so of material otherwise used to drive the pyrolysis would be a useful gain.

    A particularly interesting possibility is to use wind generated electricity as the power source. Microwave pyrolysis with gas storage provides an opportunity to convert this inconveniently erratic supply so that it can be used as and when energy is required.

  4. J A Ginsburg April 13, 2009 at 9:26 am #

    re Tom G's comment: "But biochar -the end product- won’t… put food on your table." Biochar is what make terra preta fertile. It creates a matrix around which microbe and all sorts of good things can work to improve soil. That's food. On the table. And pretty wonderful.

  5. Nando July 24, 2009 at 6:11 am #

    The economics of shifting biomass over distance isn't the only problem with the argument that biochar would drive deforestation, especially if the price on carbon was high enough. Carbon accounting methods used in emission reduction markets extended to biochar would look to the decomposition rate of the biomass used as feedstock as a baseline, (what else could be used???) and factor that in on a year over year basis. So in the case of standing forest, even if it would be allowed to clear the wood under certain circumstances to be uses as the feedstock in a biochar carbon market methodology, the slow decomposition rate of the baseline case would mean that carbon credits based on the carbon sequestered would only accrue very, very, very slowly, over perhaps 50 to 100 years. In effect, you'd have to wait a long time to realize the monetary benefit from the carbon credit, so long that it would be worthless.

  6. Mark Chapin December 8, 2009 at 11:16 pm #

    As a small farmer I would disagree with some comments. I feel bio char will be a huge asset to agriculture, or it should be. Right now 100 pounds of fertilizer may have over 50 pounds of inert products (waste products). That inert ingredient should be carbon which will help rebuild the organic matter in our soils. I agree that hauling light weight bulky carbon cross country does not make any sense. Every Farm/Ranch in the country should be making carbon or at least a local COOP. But the design needs to be economical to construct. Remember farmers/ranchers pay retail and sell wholesale. Thus the margins in agriculture are very slim. I have tried numerous methods for making carbon. Presently I am using waste vegetable oil to heat my oven. I use WVO to power all my diesel equipment. The WVO that is not suitable for power equipment I am using to produce heat for my carbon oven. Keep up the good work

    • Dan Young April 7, 2010 at 8:40 pm #


      Reading your comments about Disarming the Biochar Wars, I think you're right on. Ag waste is the right fuel for biochar production, and it needs to be done right on the farm. I'm a nut for doing it efficiently and not wasting any heat. And it must be done in the cheapest possible way! Ideally it should drive a combined heat and power system. I have some ideas as to the best way to do some of it but not all of it. Got any ideas for controling the moisture content of the feed?

      Its hard to do it the best possible way and still do it cheap! Still, I'd like to talk to someone experienced.

      Dan Young


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