1. Revision of chapter 5.B. Anaerobic digestion at biogas facilities
© m.paterson
Revision of chapter 5.B. Anaerobic digestion at biogas facilities
Sebastian Wulf, Hans-Dieter Haenel
TFEIP-meeting Krakow,

2. Schedule
17.May 2016: TFEIP meeting in Zagreb. Discussion on revised chapter 5.B.2. for EMEP 2016 guidebook:
- Need of improvement for existing revised chapter
ad-hoc group of the Ag&N-panel established
suggestion to be elaborated by Hans-Dieter Haenel (Thünen Institute) Sebastian Wulf (KTBL)
08.July 2016: suggestion for improved chapter sent to ad-hoc group
22.July 2016: deadline for response by ad-hoc group
04.Aug 2016: revision based on the remarks of group members sent to the ad-hoc group
17.Aug 2016: deadline for response by ad-hoc group
19.Aug 2016: final version sent to chairs of Ag & N-panel

3. Reasons for ad hoc group
Improvement of needed, because:
3B (manure management) described mass flow of N from manures going into anaerobic digestion, but no corresponding N-flow was accounted for in chapter 5B.2 (anaerobic digestion)
Missing definitions (processes, technologies, …)
Emission equations not properly based on mass flow considerations.
Emission factors given were related to fresh matter and could not be applied to the amounts of N (or rather TAN) in animal manures used as feedstock.
Guidance was missing how to account for the emissions from spreading of digestates -> should be reported in 3D under 3Da2c
Uncertainties of water content

4. Aim of revision
Due to the restricted time of revision, the following decision was made by the ad-hoc group:
Restrict the chapter to NH3 (as in existing chapter)
Description of all relevant aspects of biogas process. No detailed parameters not relevant for described methodology.
Check the emission factors based on Cuhls et al. for consistency with other calculations.
Establish links to 3B (slurries entering AD) and 3D (digestate spreading).
Assumption: all digestates spread in agriculture

5. Major changes
Technology description shortened/restricted to described methodology
EF were checked and decided to stick to Cuhls et al. (other options not possible within time frame)
Calculations and EF were transformed to be based on N-mass in feedstock (instead fresh matter)
Information on N-content of various feedstocks for AD is given in case only fresh matter masses are known.
Tier 1 method introduced (was missing so far)
For emission control, reference is given to chapter 3B (storage)
Clear linkages to chapter 3B (slurries entering AD) and 3D (digestate spreading) introduced.
General structure not changed

6. Major changes
Technology description shortened/restricted to described methodology
EF were checked and decided to stick to Cuhls et al. (other options not possible within time frame)
Calculations and EF were transformed to be based on N-mass in feedstock (instead fresh matter)
Information on N-content of various feedstocks for AD is given in case only fresh matter masses are known.
Tier 1 method introduced (was missing so far)
For emission control, reference is given to chapter 3B (storage)
Clear linkages to chapter 3B (slurries entering AD) and 3D (digestate spreading) introduced.
General structure not changed

7. Future More detailed mass flow concept
Thorough review on emission factors (now: only based on one study)
Inclusion of other N-flows (N2,N2O, NOx)
Consideration of changes in TAN-contents through digestion ….
Revision should be aligned with IPCC revision process

8. Thanks to the members of the ad-hoc group
Barbara Amon
Carlo Trozzi
Christoph Lampert
J. Webb
Jan Vonk
Michael Anderl
Stephanie Voshaar
Ulrike Döring