[Digestion] FW: Biogas and CO2 equivalents

[Randy Mott]

You cannot simply use the methane destroyed to derive credits. You have to
demonstrate that the methane destroyed would have otherwise gone into the
atmosphere. So a 1 MW biogas plant that actually destroys 116,000 tons of
CO2 equivalents a year, will typically receive only about 20-40,000tons of
actual credit. There are elaborate formulas for this calculation .....

See http://cdm.unfccc.int/methodologies/index.html

Randy Mott
CEERES
Warsaw



-----Original Message-----
From: digestion-bounces at lists.bioenergylists.org
[mailto:digestion-bounces at lists.bioenergylists.org] On Behalf Of James
Fidell
Sent: Tuesday, December 21, 2010 1:07 PM
To: digestion at lists.bioenergylists.org
Subject: Re: [Digestion] FW: Biogas and CO2 equivalents

> How do you convert M3 of biogas produced to CO2 equivalents or Carbon 
> Credits - is it 1000 m3 = 1 tonne of CO2 equivalents ?? of 100 m3 of 
> biogas to 1 tonne of CO2 equivalents  and we don't have to be to 
> precise, just general  !!

I'm only familiar with the UK metrics because they're the ones I'm dealing
with at the moment, but in the case of biogas I'd imagine they're very
similar all over the world (some energy sources have different metrics
between countries and even for different areas of the same country).

The biogas figure I have comes from the 2010 DEFRA/DECC GHG metrics and
gives 2040kg of CO2 equivalents per tonne or 0.246kgCO2e per kWh (net
CV) of biogas as a mixture of 60% CH4 and 40% CO2.  I don't have figures for
emissions by volume, but my schoolboy chemistry suggests that's likely to be
more difficult given the need to account for variations in temperature and
pressure.

James

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for more information about digestion, see Beginner's Guide to Biogas
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