Thanks for sharing this, Tony. What time period were you assuming for the 1 kg of biomass per square meter to be produced? Since you must be figuring dry mass, this cannot be an annual figure, can it?
500-600 g of charcoal would amount to a pretty impressive volume, I'm guessing. If it is going to be incorporated into the primary root zone, that would be the top 6 inches. Is that plausible? "This is about 10% of the carbon mass based on the 3% land area scenario. In other words, if 3% of the earth's land area were devoted to biomass production and associated carbon sequestration following pyrolysis to char, atmospheric CO2 would be reduced by 100ppm every 10 years." You lost me there. I couldn't discern the chain of reasoning that got you to that conclusion. Could you elaborate? Joel At 07:56 PM 1/15/08 -0500, you wrote: >Here are some simple estimates related to biochar. Please point out any >mistakes. >For rough estimate purposes, suppose the equivalent STP atmosphere is 1 >km thick. Each square km of the Earth's surface thus contains roughly >10^12 liters of gas and at 22.3 L/mole contains 4x10^10 moles of gas. >To reduce CO2 by 100 ppm requires removal of 4x10^6 moles of carbon or 4 >moles of C per square meter (e.g. about 60 grams). The top foot of soil >weighs about 500 kg so 60g of C amounts to only 0.1% of this soil mass. >If 1% of the earth's surface (3% of land area) were utilized to >sequester 100ppm equivalent C, then the soil concentration of C would be >about 10% by weight. Carbon is bound up as biomass at a variety of >annual rates depending on growing region, vegetation type, and weather. >Assuming 1 kg of biomass production per square meter, about half of this >mass could be returned to the soil as char (500 g/m^2). This is about >10% of the carbon mass based on the 3% land area scenario. In other >words, if 3% of the earth's land area were devoted to biomass production >and associated carbon sequestration following pyrolysis to char, >atmospheric CO2 would be reduced by 100ppm every 10 years. The >associated worldwide level of biomass production is about 4x10^12 kg/yr >(4 billion tons/yr). > >Tony Nekut > >-----Original Message----- >From: [EMAIL PROTECTED] >[mailto:[EMAIL PROTECTED] ><mailto:[EMAIL PROTECTED]> ] On Behalf Of >Joel and Sarah Gagnon >Sent: Tuesday, January 15, 2008 2:57 PM >To: Sustainable Tompkins County listserv >Subject: Re: [SustainableTompkins] Inspiring article on Biochar, a high >leverage solution > >This comment points to the problem I see. Since the biochar process >would require harvesting only a fraction of the energy in the biomass, >there would be an economic disadvantage to doing that instead of >capturing as much of the available energy as possible by "going all the >way to ash". >That would have to be subsidized somehow -- perhaps using carbon >credits. > >I think that the main benefit of this carbon sequestration may well lie >in the soil-amending properties and not in the CO2 capture. Compared to >the huge amount of carbon released to the environment from digging up >and burning already-sequestered fossil carbon, this is a drop in the >bucket. > >If you haven't yet taken a look at the article recommended to us by Tom >Shelley yesterday, you are missing an excellent resource. Full of >interesting and relevant information, and well written! Here is the >link: >http://www.stanford.edu/group/efmh/jacobson/WindEnergy0108.pdf ><http://www.stanford.edu/group/efmh/jacobson/WindEnergy0108.pdf> . It >makes a convincing argument that electricity is the power of the future, >with wind and solar-electric the primary sources, if we are to >rationally address the need to reduce carbon emissions as well as wean >ourselves off of dwindling supplies of fossil fuels. > > >Joel > > At 03:19 PM 1/14/08 -0500, you wrote: > >As a followup to this, I should note that the wood-driven vehicle > >conversions I referred to don't stop the combustion process at just the > >right point for biochar but actually burn the stuff down to ash. So > >this process is properly "gasification" rather than "pyrolysis." As > >far as I can tell, the difference between the two is a matter of how > >far the process is allowed to go, but clearly the biochar-producing > >power plants I was fantasizing about will be a good deal more > >complicated than the simple wood gasification units that were deployed > >in WW2. > > > >It still amazes me that you can run an ordinary gasoline engine on wood > >chips, though. > > > >Jon > > > >Jon Bosak wrote: > > > Thanks to Elan for forwarding the "Birth of a New Wedge" article. > > > Figuring out the carbon accounting is the next step in the growing > > > terra preta movement we first noticed last year. This is indeed an > > > inspiring development. > > > > > > Biochar is one of two unalloyed pieces of good news to come out of > > > 2007, the other being the finding that organic farms can be as > > > productive per acre as conventional farms (albeit much more > > > labor-intensive). This means that in theory we can decouple food > > > production from synthetic fertilizers -- a lucky thing for us, since > > > such fertilizers are created from natural gas, the North American > > > production of which has been declining for several years now. The > > > much greater input of hand labor required for organic farming at > > > this level of intensity suggests that most of us will eventually > > > have to spend at least part of each day involved in individual or > > > team-oriented food production -- a small price to pay when you > > > consider the alternatives. Besides, it's good for ya. > > > > > > Biochar is almost magic, and to my mind the most believable > > > technical fix so far proposed for greenhouse gas reduction. It's a > > > biomass energy production scheme with a carbon *negative* byproduct > > > that also appears to be the world's best long-term soil amendment. > > > So the more energy you extract this way, the more carbon you > > > sequester from the atmosphere and the more productive (over a number > > > of years) you make the soil.... which makes the biomass grow better. > > > > This circle almost seems to contradict the laws of physics, but > > > really all that's going on is an efficient and intelligently > > > directed use of the sunlight falling on the growing area. > > > > > > Here's a technofix vision for you: a farm tractor run off gases > > > generated by a wood-chip or grass-pellet pyrolizer (which requires > > > minimal modification to the engine itself), the carbon-rich biochar > > > from the pyrolizer fed out directly onto the land as a long-term > > > soil amendment.... > > > > > > A member of last year's peak oil discussion group showed how easily > > > he converted his mom's pickup to run on a wood-chip pyrolizer. It's > > > not rocket science; anyone with a welding kit could do this. During > > > WW2, conventionally powered vehicles all over the world were > > > retrofitted with locally made pyrolizing gas generators. It > > > shouldn't take long to engineer pyrolizers that eject the leftovers > > > at just the right point now that we know what we're looking for. > > > This would never produce enough gas to run our current > > > transportation system, but it could certainly produce enough to keep > > > some tractors running. > > > > > > We haven't gotten much really good news on the energy descent front > > > in recent years, but the prospect of a believable carbon > > > sequestration scheme that also provides enough to eat and some farm > > > machinery to help out finds me much cheerier going into 2008 than I > > > was going into 2007. Now if we can only teach our leaders the > > > concept of long-term planning.... > > > > > > Jon > > > > > > Elan Shapiro wrote: > > > > Birth of a New Wedge > > > > By Kelpie Wilson > > > > t r u t h o u t | Report > > > > > > > > Thursday 03 May 2007 > > > > http://www.truthout.org/docs_2006/050307R.shtml ><http://www.truthout.org/docs_2006/050307R.shtml> > > > > >>>Also see other articles on Biochar , or Agrichar, in this > > > > listserve last May, when this article came out > > ... > > > Agrichar is the term not for the biomass fuel, but for what is > > > > left over after the energy is removed: a charcoal-based soil > > > > amendment. In simple terms, the agrichar process takes dry biomass > > > of > any kind and bakes it in a kiln to produce charcoal. The > > > process is > called pyrolysis. Various gases and bio-oils are > > > driven off the > material and collected to use in heat or power > > > generation. The > charcoal is buried in the ground, sequestering > > > the carbon that the > growing plants had pulled out of the > > > atmosphere. The end result is > increased soil fertility and an > > > energy source with negative carbon > emissions. > > > > > > > > > > > > > > _______________________________________________ > > > RSS, archives, subscription & listserv information for: > > > [email protected] > > > http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins ><http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins> > > > free hosting by http://www.mutualaid.org <http://www.mutualaid.org> > > > > > > > > > >_______________________________________________ > >RSS, archives, subscription & listserv information for: > >[email protected] > >http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins ><http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins> > >free hosting by http://www.mutualaid.org <http://www.mutualaid.org> >_______________________________________________ >RSS, archives, subscription & listserv information for: >[email protected] >http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins ><http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins> >free hosting by http://www.mutualaid.org <http://www.mutualaid.org> > > >_______________________________________________ >RSS, archives, subscription & listserv information for: >[email protected] >http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins >free hosting by http://www.mutualaid.org _______________________________________________ RSS, archives, subscription & listserv information for: [email protected] http://lists.mutualaid.org/mailman/listinfo/sustainabletompkins free hosting by http://www.mutualaid.org
