© m.paterson
Activity data and methods for German
Biogas reporting
Sebastian Wulf, Sven Grebe, Dieter Haenel, Claus Rösemann
Krakow, May 11th, 2017
Sources of emissions in AD
(CO2)
CH4
CH4
CH4
(CO2)
CHP
CH4 NH3
PS
Fermenter
CH4
N2O NH
3
storage
N2O NH
3
System boundaries
sewage
treatment
gas capture
landfills
CHP
electricity/
heat
biowaste
gas
processing
Biomethane
energy
crops
Flare
slurry, solid
manure
biogas
production
digestate
storage /
processing
Agriculture
Waste
2
Energy
application
fertilizer
Calculation methodology
Waste sector
 Calculation from official statistics on treated waste products
 Cumulated emission factors including storage before digestion,
storage and application of digestates.
Agricultural sector
 No official statistics on input data available
 Tier 3 Method used for calculation
Methodology – CH4
ECH4, dig
MCF %
 VS dig    Bo   CH4 
100 %
MCF % residues 

MCF %  MCF % ps  (100 %  MCF % ps )   (1   rg )  Lprod   rg 

100
%


MCF % residues  xgts  (100  Lsto, gt )  (1  xgts )  MCF % residues,crust
Important parameters:
• Overall input of organic carbon (VSdig)
• Methane production potential of the input material(Bo)
• Residual gas potential as share of Bo (µrg)
• Leakage rate from the fermenter/gas tight system (Lprod/Lsto,gt)
• Relative share of gastight storage (xgts)
60-70% in Germany
Methodology – NH3
 Per definition = 0 for fermenter and gastight storage
 for storage without cover emission factor equals slurry storage
(with crust)
 Changes in TAN-content during digestion is accounted for
E NH3- N, dig, residues  (TAN dig  f TAN  N org, dig )    (1  xgts )  EFNH3- N, dig, residues,crust

Slurries: Survey showed, that mean TAN rises from 45% to 62%
fTAN = 0.32

Energy crops: mean TAN of digestates from energy crops: 56 % of Ntot .
fTAN = 0.56
Activity data needed
 Amount of nitrogen (and VS) entering the biogas plant
 Amount of animal manures entering biogas plant („saved emissions“)
 Relative share of gas tight storage
Information needed on:
- different input materials into digestion
- conditions of digestate storage
 No official statistics available
7
Data sources used
 Data from grid operators (Übertragungsnetzbetreiber)
- Amount of electricity fed into the grid by individual plants
- Code giving information on the feed-in tariff for the individual plant
-> identification of biogas-plants possible (in most cases)
 Survey of a private company on input subtrates into 1660 German
biogas plants (2010-2012)
 Bo (potential CH4 yield of substrates)
-> good availability for manure an energy crops
 Survey of DBFZ (German Biomass Research Centre):
Data on digestate storage (2012)
8
Substrate input
Substrate input into German biogas plants needs differentiation between:
Federal states:
• In some states larger share of manure input (e.g. Thuringia),
in others larger share of energy plants (Lower Saxony and
Saxony Anhalt)
16 federal states
Size of biogas plants:
• In smaller plants larger share of manure input
5 plant size groups
Type of substrates:
• Cattle, pig slurry and poulty manure (in order to account für
„saved emissions“ in these animal categories)
• Different gas yields (in order to calculate mass of input from
energy production)
10 substrate types
Substrate input
Specific gas yield of substrates
Electrical efficiency of CHP
Electricity produced
(per plant size and
federal state)
Substrate mix
(per plant size
and federal state)
mass of different substrates
being used
(per federal state)
N-content of
substrates
N-input with
different
substrates into AD
10
(per federal state)
Share of gas-tight storage
Survey data (DBFZ) for 2012 does not apply to current status.
 Change in renewable energy act 2012
-> all new plants need gas-tight storage
Data needed for calculation:
For each plant size group and federal state:
 Number of plants operating 2012: O2012
 Number of individual plants not operating in 2015 compared to 2012
(closed plants): C2015
 Numbers of plants operating in 2015: O2015
Share of gas-tight storage
Number of plants operating 2015 (initial operation before 2012):
P2015_old = O2012 - C2015
Xgts from survey
for 2012
Number of plants operating 2015 (initial operation after 2012):
P2015_new = O2015 - P2015_old
Xgts = 1
Weighing for produced energy of each plant size group:
Xgts per federal state
Effect on reported emissions
Increase/decrease of reported emissions, if input is considered of:
Difference in emissions [kt a-1]
manure only
manure and energy crops
60
52
50
40
30
20
8
10
0
-36
1
0
6
-10
-20
-30
-40
CH4
N2O
NH3
(Submission 2015)
Effect on reported emissions
Increase/decrease of reported emissions, if input is considered of:
Difference in emissions [kt a-1]
manure only
manure and energy crops
60
52
50
40
30
20
8
10
0
-36
1
0
6
-10
-20
-30
-40
CH4
N2O
NH3
(Submission 2015)