[Gasification] Biochar - Carbon Negative?

[Gerald Kutney]

While biomass is carbon neutral in principle, its use seldom is as the collection and processing of it is not.  The claim of carbon neutrality in the use of biomass has opened the industry to valid criticism as over-stating its benefits.  Bioenergy and biofuels are better than fossil fuels, but carbon neutrality is a hyperbole, in my opinion.

And while biochar is carbon negative in principle, not all of it is fixed and some appears to be vulnerable to biological activity.  Proving the degree of sequestration is challenging, and few jurisdictions have officially accepted this aspect of biochar.  

That said, bioenergy, biofuels and biochar are all (usually) beneficial to fight climate change (compared to fossil fuels), but we should be careful not to overstate the degree that this takes place.


Gerald Kutney, Ph.D.
Managing Director
Sixth Element Sustainable Management
“Innovation can move the world”
www.6esm.com (613) 425-0619

From:  Gasification <gasification-bounces at lists.bioenergylists.org> on behalf of Anand Karve <adkarve at gmail.com>
Reply-To:  Discussion of biomass pyrolysis and gasification <gasification at lists.bioenergylists.org>
Date:  Wednesday, April 20, 2016 at 4:43 AM
To:  Discussion of biomass pyrolysis and gasification <gasification at lists.bioenergylists.org>
Subject:  Re: [Gasification] Biochar - Carbon Negative?

Dear Doug,
biomass is formed by the process of photosynthesis. Burning biomass is considered to be carbon neutral, because the carbon dioxide produced in this process was originally already in the atmosphere before it got sequestered in plants by photosynthesis. After being released into the atmosphere by burning, it would be sequestered again in plants by photosynthesis. Therefore, the carbon dioxide added to the atmosphere is zero. if any of the biomass is converted into char and buried into the soil, it creates a negative carbon dioxide balance, irrespective of the proportion of char going into the soil.
Yours
A.D.Karve

***
Dr. A.D. Karve

Chairman, Samuchit Enviro Tech Pvt Ltd (www.samuchit.com)

Trustee & Founder President, Appropriate Rural Technology Institute (ARTI)

On Wed, Apr 20, 2016 at 11:24 AM, Doug Williams <doug.williams.nz at gmail.com> wrote:
Hi Mark,

You ask:
> After gasification, approximately 5% of the woody biomass remains a biochar
> which sequesters carbon, hence a 'carbon negative' claim can be made.

Qualify which type of gasification, because 5% would only apply to a
high performance gas making system. If however it was a pyrolysing char
making system, about 1/3rd of the fuel weight would be char, but two
thirds would be consumed by combustion to become a CO2 emission. So not
honestly carbon negative in my opinion (other than replacing fossil
carbon). Restoration of the environmental CO2 balance would be a tricky
calculation.

> Alternatively, if the woody waste is left to rot in situ, the carbon
> sequestration is 0% (all carbon is released/transformed into CO2 and other
> gasses).

That fits the normal explanations, we all go back to CO2 and CH4 if
left to rot(:-)

> True?

Truth can be very elastic sided when claims are made about
gasification, so take care to confirm all calculations regarding the
process in question.There is a lot of attention paid to carbon credits
as an intensive to cheat in the Souther Hemisphere, and one should be
careful if included in any proposals.

Doug Williams,
Fluidyne.

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