[Terrapreta] ? GHG emissions from Biomass Combustion ?

[Sean K. Barry]

Hi Tony,

 

Methane-CH4 is a very important GHG, even without being synthetic in origin.
Potential natural sources of Methane-CH4 emissions include termites,
ruminent animals, volcanos, permafrost frozen wetlands and other temperate
and tropical wetlands, rice patties, and sea floor methyl hydrate stores
(frozen CH3OH).  Human sources include landfills, biomass burning, waste
treatment, and some industrial oil refining operations, I think.
Methane-CH4 has 23 times the GHG potential as CO2 for 100 years.  Its actual
effect is 62 times more potent with a life of about ~8 to ~10 years.  There
are Methane-CH4 sinks too, but total atmospheric concentrations are still
rising.

 

See this page -> http://en.wikipedia.org/wiki/Methane 

 

There is a section on that page ...

 

Sudden release from methane clathrates 

At high pressures, such as are found on the bottom of the ocean, methane
forms a solid clathrate <http://en.wikipedia.org/wiki/Clathrate>  with
water, known as methane hydrate
<http://en.wikipedia.org/wiki/Methane_clathrate> . An unknown, but possibly
very large quantity of methane is trapped in this form in ocean sediments.
The sudden release of large volumes of methane from such sediments into the
atmosphere has been suggested as a possible cause for rapid global warming
<http://en.wikipedia.org/wiki/Global_warming>  events in the Earth's distant
past, such as the Paleocene
<http://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum>
-Eocene Thermal Maximum of 55 million years ago.

One source estimates the size of the methane hydrate deposits of the oceans
at ten trillion tons (10 exagrams)[citation needed
<http://en.wikipedia.org/wiki/Wikipedia:Citation_needed> ]. Theories suggest
that should global warming cause them to heat up sufficiently, all of this
methane could again be suddenly released into the atmosphere. Since methane
is twenty-three times stronger (for a given weight, averaged over 100 years)
than CO2 as a greenhouse gas; this would immensely magnify the greenhouse
effect, heating Earth to unprecedented levels (see Clathrate gun
<http://en.wikipedia.org/wiki/Clathrate_gun_hypothesis>  hypothesis).


[edit
<http://en.wikipedia.org/w/index.php?title=Methane&action=edit&section=18> ]
Release of methane from bogs


Although less dramatic than release from clathrates, but already happening,
is an increase in the release of methane from bogs as permafrost
<http://en.wikipedia.org/wiki/Permafrost>  melts. Although records of
permafrost are limited, recent years (1999 to 2007) have seen record thawing
of permafrost in Alaska <http://en.wikipedia.org/wiki/Alaska>  and Siberia
<http://en.wikipedia.org/wiki/Siberia> .

Recent measurements in Siberia show that the methane released is five times
greater than previously estimated [17]
<http://en.wikipedia.org/wiki/Methane#_note-14> .

and ...

Slightly over half of the total emission is due to human activity.[11]
<http://en.wikipedia.org/wiki/Methane#_note-Technical_summary> 

This points to some potential problems with Methane-CH4 and/or things to
watch for, I think.  Although now, about ~1/2 of Methane-CH4 emissions are
man-made, with continued temperature rise, the natural sources like
permafrost frozen wetlands and bogs, and thawing sea floor methyl hydrate
releases may become more frequent and tip the balance towards more natural
emissions of Methane-CH4.  Apparently human activity emits less Methane now
in the most recent decade than we have since in times since the industrial
revolution began.  So, we perform better with anthropogenic Methane-CH4
emissions now, but it might not matter, if the climate makes one of these
chaotic complex system "slips" and the radical heat rise, cause a radical up
tick in natural releases/emissions of Methane-CH4.

Folke Gunthur says this very clearly in his paper (attached) and Power Point
Presentation:  levels of GHG in the atmosphere are already too high (the
Folke's .ppt is available on http://terrapreta.bioenergylists.org site, I
think).  Now, reducing human emissions rates of GHGs alone won't solve the
problem.  Actual reductions of atmospheric concentrations of GHG is the only
workable solution for the problem at hand.

The formation of Terra Preta, strictly as a means to reduce levels of CO2 in
the atmosphere by sequestering charcoal (carbon)-in-soil is one very viable
way of "mining CO2 (carbon) from the atmosphere".  In the process of
harvesting and processing biomass into charcoal, some energy can also be
harvested.  Doing both (making charcoal-for-soil and harvesting energy) from
biomass sources has the treble effect: 1) it fights correctly (with a real,
workable problem mitigation strategy) against rising atmospheric
concentrations of GHG (and the resulting rising temperatures and climate
changes), 2) it could improve the fertility and agricultural potential of
the soils containing the charcoal, and 3) it can do these and also provide a
renewable energy resource to replace fossil fuel energy sources as they
deplete (or become illegal to use because they emit to much CO2!).

Humans should be wary of all Methane-CH4 emissions, and carefully in control
of synthetic sources, but we should really concentrate on getting the
concentrations of ALL of the main GHGs down as close to pre-industrial
levels as we can, as fast as we can.  We are kind of playing with "fire",
with this anthropogenic induced climate change, I think.  The main GHG
concentrations in the atmosphere are now CO2@~380ppm, CH4@~1750ppb, and
N2O@~317ppb.  These all need to be lowered before something happens and
cause a runaway "feedback" cycle like, (heat up <=> more natural releases of
Methane-CH4).  We could be praying for an Ice Age to reoccur.

Nitrous oxide-N2O emissions come primarily from decomposition of
industrially produced, fossil fuel based, high nitrogen fertilizers.
TP soils do not need as much high nitrogen fertilizers as native soils.
Make TP, reduce fertilizer use, and reduce N2O emissions.

Regards,

SKB

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

From: Tony Lovell <mailto:tonyl at soilcarbon.com.au>  

To: 'Sean K. Barry' <mailto:sean.barry at juno.com>  ;
terrapreta at bioenergylists.org ; Shengar at aol.com 

Sent: Monday, March 10, 2008 6:56 PM

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

 

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

 

 


  _____  


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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