Maybe bio-char does have a part to play

Terra preta is the very fertile black soil found mostly in parts of the Amazon basin, and believed to have been created by people mixing fine particles of charcoal and other stuff into the soil. A whole lot of voodoo has grown up around the subject, with unscrupulous charlatans, head in the sand naysayers and all manner of other life forms clustering around the idea. Some people think that one can create terra preta by adding bio-char to the soil, and that miracles will ensue.

I recently dumped on biofuels from a great height because in essence they are mining the soil. Doesn’t matter how slowly; at some point, the fun will have to stop. In the comments on that post, Karl and Anastasia weighed in by saying that bio-char, a potential residue after extracting bioenergy, could be returned to the land to close the loop. I dumped on that idea too.

Now I’m not so sure. Not about bioenergy. I still think that’s a false god, methadone for the oil-addicted masses. But terra preta could just be a solution to excess carbon dioxide in the atmosphere.

Why the change of heart? Because yesterday I went to a very interesting presentation by a very smart, very rich and very tenacious man who has a history of wild and crazy ideas that turn out to be correct, and he talked about terra preta not as a by-product of bioenergy production but as a direct solution to removing carbon dioxide from the atmosphere.1

He had some interesting figures to share, although in my excitement, I didn’t write all of them down. As I remember, to get atmospheric carbon down from 380 parts per million or thereabouts to 280 ppm we would “only” have to spread a 1 mm layer of bio-char each year on, I think, just the cultivated part of agricultural land for 50 years. That amounts to 5 cm of bio-char, and gets us back to pre-industrial levels of atmospheric carbon dioxide.

It didn’t seem all that much.

What struck me, listening, was that the argument was not couched in terms of bioenergy at all. I think reference may have been made to using some of the energy derived from the pyrolysis of plant matter that creates bio-char in order to power the plant.2 It was all about learning to make use of bio-char to create terra preta — which almost certainly needs to be tailored specifically to different growing areas — in order to sequester carbon. The oil addicts will have to take care of themselves. This was about saving the planet for the rest of us.

I still have lots of questions, which under the circumstances I wasn’t able to ask. Like:

  • If the pyrolysis plants have to be large, how will the bio-char be returned to the soils from which it came?
  • If the plants can be small, can they be made simple enough and cheap enough for individual communities to use them?
  • Would it pay? Really?
  • What about the other soil nutrients? Should the bio-char go back whence it came? Or is this a good way of transferring nutrients from reasonably self-sustaining systems (prairie?) to land currently unfit for cultivation? Maybe that just adds costs to transport and incorporate the bio-char.

I know there are lots and lots of people out there working on answers, and they aren’t all charlatans or naysayers. I also know that I cannot now get further involved.

I just wanted to note that maybe bio-char is a useful solution to carbon sequestration, although sustainable bioenergy remains a pipe dream.

  1. I’m not going to name names or give details because I’m honestly not sure how public the idea is; I Googled the guy, obviously, and the idea. He’s there, but he doesn’t seem to be associated with the idea, so I’m keeping mum, for now. []
  2. Pyrolysis requires energy, so the process certainly is not going to be self-sustaining. []

17 Replies to “Maybe bio-char does have a part to play”

  1. so, and I’ve not looked yet so I apologise for being ill educated on this, how does bio-char differ from the old habits of saving the wood ash from the fire or having a bonfire of the weeds or even just a good hot compost pile and spreading the results of that. I can’t see how it locks up carbon. I will go and look now, promise, but I’d never heard of this and those were the questions that came to me.

  2. O.k. I’ve got it now, so please delete my stupid reply above.

    Are you sure this isn’t being funded by those who would like to justify their destruction of the rain forests?

  3. A good hot compost pile does get close, but ash after combustion has lost an awful lot of the carbon to carbon dioxide. No impact on atmospheric CO2, of course, since the plants took up that carbon from the atmosphere in recent time.

    Like I said, there are a good many kooks around the subject, but the person I heard certainly isn’t destroying any rainforests. I can vouch for that.

  4. Don’t know… I’m reading a lot about biochar and I’m not able to make up my mind… just get more and more fuzzed… I’m looking to star a little experimental garden next year but I think the scale is a key factor. Anyway, still mumbling… Thanks for your work.
    (excuse me for my english…)

  5. Great to see that you are checking out biochar. It is gaining widespread interest as a way to address world hunger, climate change, rural poverty, deforestation, and energy shortages… SIMULTANEOUSLY!

    Indeed, James Hansen is now placing it in the center stage of pro-active solutions for the climate crisis.

    If you would like to get out of the noisy arguments and into the positive vision, please check out and beyondzeroemissions.

    The BBC documentary The Secret of El Dorado is what propelled Terra Preta into global awareness and the Australians especially have been providing exciting documentaries about current applications.

    And if you would like to plunge deeper there is a great terra preta forum and information archive here.

    Thanks for giving biochar your consideration.

    Lou Gold

  6. I hope you will come to share my passion in getting the word out on the wonderful solutions provided by Terra Preta soil technology (TP, aka Biochar).

    If pre-Columbian Kayopo Indians could produce these soils up to 6 feet deep over 15% of the Amazon basin using “Slash & CHAR” verses “Slash & Burn”, it seems that our energy and agricultural industries could also product them at scale.

    Harnessing the work of this vast number of microbes and fungi changes the whole equation of energy return over energy input (EROEI) for food and Bio fuels. I see this as the only sustainable agricultural strategy if we no longer have cheap fossil fuels for fertilizer.

    We need this super community of wee beasties to work in concert with us by populating them into their proper Soil horizon Carbon Condos.

    This technology represents the most comprehensive, low cost, and productive approach to long term stewardship and sustainability.Terra Preta Soils a process for Carbon Negative Bio fuels via Pyrolysis of Biomass………, Massive Carbon sequestration via Biochar to soils (1/3 ton C per 1 ton Biomass)……………, 10X Lower CH4 & N2O soil emissions………….., and 3X Fertility Too.

    What’s not to love??

  7. I really don’t mean to be incendiary, but I can’t help but ask – if not biofuels, then what? Unless there is a complete change in the structure of Western society (honestly, everywhere), we’re going to need some type of portable energy. Batteries are basically containers of toxic sludge, hydrogen is a pipe dream, solar and wind don’t apply to cars….

  8. Well, solar and wind can apply to cars if the cars are plug-in hybrids that get charged up by them for the regular commute.

    We’re going to have to do something, because even right now, with gas ONLY at $4/gallon, politicians are talking about doing more drilling, and will probably not blink about approving more coal power plants. Even though the long-term sustainability of biofuels is in question given current methods, surely it must be better than that?

    Welcome to the secret bio-char fan club – I came across it a couple years ago and mentioned it on my show. Since then, it’s been popping up again and again and sounds more promising.

  9. Enhanced Geothermal Systems (EGS) have much to recommend them as ubiquitous sources of energy that can be used to synthesize all manner of commodities – such as liquid fuels for transportation – from air, rocks and water.

    The net energy gain from pyrolysis might be best used for synthesis of fertilizer, squaring the circle so to speak, since it results in more biomass. When integrated into the biochar production system – such as with Eprida’s system of nitrogen doped biochar – the result is a timed release fertilizer that has greater effect and less loss to leaching or denitrifying bacteria, and so fewer GHG emissions. Less fertilizer is needed for increased yield and less environmental stress.

    I think of it as environmental jiu-jitsu, finesse rather than brute force.

  10. The pyrolysis process in itself is endothermic, but it produces three types of products:
    * Charcoal
    * Noncombustible gases (mostly steam)
    * Combustible gases – carbon monoxide, hydrogen, methane, and vaporized organic compounds.

    There is more than enough energy in the combustible gases, if it is burned to heat the pyrolysis chamber, to drive the pyrolysis process. This is shown in barrel kilns, which after an initial startup with an outside fire, are self-sustaining until the process is complete, even with lost heat.

  11. Yes, continuous process pyrolysers are being developed; a batch process is just a simple example of the basic principle.

  12. You must read this
    “The Biochar Revolution” with “The Biochar Solution”

    The Biochar Revolution collects the results and best practical advice that these entrepreneurs have to offer to the biochar community. When practice and theory advance to the point where they meet in the middle, then we will truly see a biochar revolution.

  13. I see several issues…
    1) The person pushing it is “Rich” there is no altruism in his concept so there is going in the long run an environmental disaster down the line.
    2) Bio-char is not just charcoal, it is incompletely combusted wood with some (up to 40%) complex organic compounds. To control the carbonization you will need a extremely sophisticated system to carefully carbonize the wood. Too much it charcoal too little and your feeding termites which may be WORSE.
    3) For it not to be consuming large amount of either wood as fuel or fossil fuels for its transport it would have to be done in small local plants and returned to local farms.
    4) If the spread of the bio-char is not just right you could end up with under soil fires which very difficult to extinguish.
    5) Terrapreta earths are only seen in tropical rainforest’s and may not be applicable or should I say reproducible outside of Tropics.

    Note I am not dumping on the idea of biochar, it is potentially and important part of sustainable environmental solutions. However there need to be quite a bit of research to see if it will work outside of tropical rain forest before we can call it a panacea for human driven global warming.

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