GHG emission is inevitably combined with all non-renewable energy use and furthermore with a number of other
processes in the biogas system. Methane emission takes place during electricity production and biogas upgrading
and possibly from leakage of methane from the digester and the digestate storage. On the other hand, methane
emission from manure storage can be largely avoided, which explained the very high efficiency especially for liquid
manures. Nitrous oxide emission takes place after soil application of the digestate, but the emission from soil
application of crop residues and manure is avoided. Furthermore, the N2O emission from manufacturing and
application of the saved mineral fertiliser nitrogen is avoided.