[Digestion] Contents of digestion digest

[David]

Bill,

On 1/1/2011 11:53 PM, Bill Rucks wrote:
> Some one must have a idea on that very simple equation 1000 - 10 m3 of biogas is equal to 1 tonne of co2 equivalents ??????  We will never build a large multiple of these system unless we have a idea on that ratio -  an surly building lots of small systems will benefit lots more people - than big companies - the big companies have got us into this predetermine that we find our selves in !!!

Do forgive me if it was not clear, but if you consider my previous 
answer carefully, you will see that CO2 equiv is not a fixed metric-- 
there is no such fixed ratio between volume of biogas produced and CO2 
equiv saved, /it does not and cannot exist/, to be quite clear about 
it-- but rather is situational. In order to earn carbon credits, one 
must demonstrate, in a rather specific way and for a specific 
situation, that a given digester or group of digesters is likely to be 
saving a certain tonnage of CO2 equiv. Explore the UNFCCC website, and 
if you can wade through the somewhat unsatisfactory search process 
provided, you can uncover a wealth of documents about small biogas 
digester projects that have gone through the process and produced 
their answers.

My exploration of those documents and a wealth of other information 
leads me to believe that it should be possible in many situations to 
experience an annual CO2 equiv savings of a bit better than a tonne 
and a half per cu m digester, but so many factors intervene that one 
must also assert that the ballpark is rather large. For example, if 
the digesters built for a given project have a tendency to leak, then 
by rights the very powerful effect of methane as a GHG should be 
factored in to the calculations, and might even erase a major portion 
of the claimed savings.

You've simply got to widen the scope of your question in order to come 
to any reasonable answer. What is the situation now, how many tonnes 
of CO2 equiv are presently being produced, and, under the 
circumstances that apply-- weather, number of animals per family, size 
of digester, etc., etc.-- how much of that can be offset by using the 
expected biogas?



d.
-- 
David William House
"The Complete Biogas Handbook" |www.completebiogas.com|
/Vahid Biogas/, an alternative energy consultancy |www.vahidbiogas.com

|
"Make no search for water.       But find thirst,
And water from the very ground will burst."
(Rumi, a Persian mystic poet, quoted in /Delight of Hearts/, p. 77)

http://bahai.us/
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