[Digestion] FW: Biogas and CO2 equivalents

[James Fidell]

> 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