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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