[Terrapreta] Terra Preta Trials 2007

[Ron Larson]

Answer to question from Robert Niederman, asking today:

> I have a question.  I've run across this concept that making charcoal
> actually ""sequesters" carbon.  Sequester a beautiful word.  But what
> does it actually mean when it comes to making charcoal?  Every fire I
> have seen, including those made with charcoal have lots of smoke.  Yes,
> we have carbon in the charcoal.  But we also have about half of it in
> the atmosphere. Where does the "sequestering" come in?  Are we saying
> that by making charcoal we are pulling the carbon out of the
> decomposition chain which occurs when we compost?

     I would say you have the idea behind the word "sequester" approximately 
correct. But making the charcoal is not enough, since the charcoal itself 
can be later burned.  The sequestering comes when the charcoal is 
sufficiently well mixed in the soil that it cannot be "un-mixed."

    Re your last sentence, I would add that we have to also remind people 
that the photosynthesis process is taking CO2 out of the atmosphere (using 
sunlight) to create the biomass that can be pyrolyzed ("charcoaled").  You 
are of course correct about compost decomposition being prevented, and we 
need to educate that charcoal is "almost" unable to be decomposed.

    Most discussion on the web about "sequestration" assumes that CO2 from 
burning fossil (almost always talking coal) resources is liquified and 
"stored/sequestered" at great depths.  Despite billions of federal dollars 
in so called "clean coal" research, there are no real-world working examples 
of CCS = carbon capture and sequestration.  I exclude EOR enhanced oil 
recovery as a realistic CCS alternative, since that approach leaves lots of 
chance for release through the thousands of drill-holes in most oil and gas 
fields.  When you see the word IGCC, there is an implied CCS option about 
which there is rarely any discussion.   Terra Preta soils as an alternative 
means of sequestration avoids huge costs and uncertainties that the utility 
and coal industries have chosen to procrastinate on when they are not 
ignoring the topic.  IGCC itself has very serious cost problems - but the 
main problem is with the CCS portion of the duo.

    You also give me a chance to raise the question from several weeks ago 
about placing coal dust rather than charcoal into the soil.  I have looked 
and found nothing meaningful - but think this is apt to be a real loser. 
Coal is the major source of uranium.  Coal has none of the porosity 
characteristics of charcoal.  Has anyone found anything to suggest coal 
could replace charcoal?

Ron