[Terrapreta] ? GHG emissions from Biomass Combustion ?

[Tony Lovell]

Sean

Agreed - natural cyclical GHG's are not a nett contributor - it is only the
non-cyclical and human released GHG's that are of concern. Do you consider
the same distinction applies to CH4 created as a natural part of the
oxidization process by methanogenic bacteria in rumination of grass-fed
animals? For aeons bison, wildebeest, termites etc have been producing CH4,
and this CH4 has been cycling back via atmospheric degeneration into CO2 and
H20, then back into the plants via photosynthesis, and around the cycle once
again.

If the ruminant animals are managed in such a way that their feed intake of
grass and herbage is naturally produced without artificial fossil fuel
inputs then the gasses produced as a result of their oxidization of the
biomass should result in no net gain as well.

Your thoughts please

Thanks

Tony

 

 

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From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Sean K. Barry
Sent: Tuesday, 11 March 2008 12:53 AM
To: terrapreta at bioenergylists.org; Shengar at aol.com
Subject: Re: [Terrapreta] ? GHG emissions from Biomass Combustion ?

 

Hi Erich , Tony,

 

There is an important distinction that needs to be made about what is the
real problem with green house gases (GHGs) in the atmosphere.  Increasing
concentration are the problem.  Biomass can produce gases from combustion
which are classified as GHGs.  However (and this is a critically important
distinction), burning biomass CANNOT increase GHG concentrations in the
atmosphere!  The cellulose, hemi-cellulose, lignin, sugars, and starch, that
are in biomass are made via photosynthesis when the plants are growing and
taking CO2 and H2O from the Biosphere.  Releasing those gases back into the
atmosphere, there is no net gain.

 

Fossil carbon in fossil fuels, though, like liquid petroleum, solid coal,
and natural gas is ~300 million year old carbon which has not been in the
atmosphere for ~300 million years.  EMISSIONS ONLY FROM BURNING FOSSIL
CARBON FUELS OR DECOMPOSTION OF FOSSIL CARBON DERIVATIVES will increase the
relative concentrations of GHG in the atmosphere.

 

There is one caveat about this, though. The emissions of Methane-CH4 or
Nitrous oxide-N2O from products made with biomass reactants can be a
significant contributing factor to Global Warming or Global Climate Change.
CH4 is 23 times more potent as a GHG and N2O is 296 times more potent than
CO2 is at "re-radiating" infrared radiation (heat) back down from the
atmosphere to the surface of the Earth (where the heat came from).

 

Open burning of biomass releases mostly CO2 and H2O (complete combustion
products).  These are both GHG, but again, they do not increase atmospheric
concentration of these gases.  If biomass is heated in an oxygen deprived
environment (like an enclosed kiln), however, then it can release Hydrogen
gas-H2, Carbon Monoxide-CO (neither are GHG), and Methane-CH4 (a powerful
GHG).  The concentration of Methane-CH4 in the "producer gas" coming from
such a reaction will be only 2-3%.  At 3%, the GHG warming effect of that
Methane-CH4 outweighs all of the CO2 or H2O that were produced in the
reaction.

 

So, kiln users must "Flare" or otherwise burn or use the CH4 fuel gas
component exiting from their devices.

 

Regards,

 

SKB

----- Original Message ----- 

From: Shengar at aol.com 

To: terrapreta at bioenergylists.org 

Sent: Sunday, March 09, 2008 10:38 PM

Subject: [Terrapreta] ? GHG emissions from Biomass Combustion ?

 

Hi All, 

Could anyone provide the figures Tony Lovell is asking for below;

 

"Erich

Thanks you for sharing our work with your colleagues at TP. 

Would you or any of your colleagues be able to assist me with finding some
information?

I am looking for general parameters on how much of what GHG's are produced
due to the combustion of biomass. In particular if we were to combust say
1,000kgs dry matter of switchgrass or similar material how much CO2, CH4,
CO, etc etc would be released. 

Any assistance you can provide is greatly appreciated.

Take care,

Tony Lovell

 Soil Carbon (Australia) Pty Ltd

PO Box 157, BOND UNIVERSITY QLD 4229

Suite 102, 20 Lake Orr Drive, VARSITY LAKES QLD 4227

Ph: +61 (0)7 5553 7900 Fax: +61 (0)7 5553 7999 Mob: +61 (0)418 730340
Email:  <mailto:tonyl at soilcarbon.com.au> tonyl at soilcarbon.com.au

 

 

 

Thanks 

Erich






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