3.I - Agricultural: Other

Short description

Category Code Name of Category Method AD EF
3.I Agriculture: other
consisting of / including source categories:
3.I Storage of digestate from energy crops T2 (NH3, NOx) Q, PS CS (NH3, NOx)

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Method(s) applied
D Default
T1 Tier 1 / Simple Methodology *
T2 Tier 2*
T3 Tier 3 / Detailed Methodology *
C CORINAIR
CS Country Specific
M Model
* as described in the EMEP/EEA Emission Inventory Guidebook - 2019, in category chapters.
(source for) Activity Data
NS National Statistics
RS Regional Statistics
IS International Statistics
PS Plant Specific
As Associations, business organisations
Q specific Questionnaires (or surveys)
M Model / Modelled
C Confidential
(source for) Emission Factors
D Default (EMEP Guidebook)
CS Country Specific
PS Plant Specific
M Model / Modelled
C Confidential

NOx NMVOC SO2 NH3 PM2.5 PM10 TSP BC CO Heavy Metals POPs
-/- NA NA -/- NA NA NA NA NA NA NA

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L/- key source by Level only
-/T key source by Trend only
L/T key source by both Level and Trend
-/- no key source for this pollutant
IE emission of specific pollutant Included Elsewhere (i.e. in another category)
NE emission of specific pollutant Not Estimated (yet)
NA specific pollutant not emitted from this source or activity = Not Applicable
* no analysis done

Country specifics

In 2022, NH3 emissions from category 3.I (agriculture other) reached up to 0.49 % from total agricultural emissions, which is equal to ~ 2.3 kt NH3. NOx emissions from category 3.I contribute 0.12 % (~ 0.12 kt) to the total agricultural emissions. All these emissions originate from the storage of digestate from energy crops (for details on anaerobic digestion of energy crops see Vos et al. 2024, Chapter 5.11). The emissions resulting from the application of energy crop digestates as organic fertilizer are dealt with under 3.D.a.2.c.

Activity Data

Time series of activity data have been provided by KTBL (Kuratorium für Technik und Bauwesen in der Landwirtschaft / Association for Technology and Structures in Agriculture). From these data the amount of N in energy crops fed into anaerobic digestion was calculated.

Table 1: N amount in energy crops fed into anaerobic digestion, in [kt N]

1990 1995 2000 2005 2010 2015 2016 2017 2018 2019 2020 2021 2022
0.0 0.6 5.3 45.1 163.0 293.7 292.2 287.4 283.2 283.2 289.3 283.8 283.8


Table 2: Distribution of gastight storage and storage in open tank of energy crop digestates, in [%]

1990 1995 2000 2005 2010 2015 2016 2017 2018 2019 2020 2021 2022
gastight 0.0 4.7 9.4 15.8 42.2 64.0 65.6 67.1 68.7 70.2 71.8 73.3 73.3
non-gastight 100 95.3 90.6 84.2 57.8 36.0 34.4 32.9 31.3 29.8 28.2 26.7 26.7

Methodology

The calculation of emissions from storage of digestate from energy crops considers two different types of storage, i.e. gastight storage and open tank. The frequencies of these storage types are also provided by KTBL (see Table 2). There are no emissions of NH3 and NO from gastight storage of digestate. Hence the total emissions from the storage of digestate are calculated by multiplying the amount of N in the digestate leaving the fermenter with the relative frequency of open tanks and the emission factor for open tank. The amount of N in the digestate leaving the fermenter is identical to the N amount in energy crops fed into anaerobic digestion (see Table 1) because N losses from pre-storage are negligible and there are no N losses from fermenter (see Vos et al. 2024, Chapter 5.1).

Emission factors

As no specific emission factor is known for the storage of digestion residues in open tanks, the NH3 emission factor for storage of cattle slurry with crust in open tanks was adopted (0.045 kg NH3 -N per kg TAN). This choice of emission factor is based on the fact that energy crops are, in general, co-fermented with animal manures (i. e. mostly slurry) and that a natural crust forms on the liquid digestates due to the relatively high dry matter content of the energy crops.

The TAN content after the digestion process is 0.56 kg TAN per kg N. The NO emission factor for storage of digestion residues in open tanks was set to 0.0005 kg NO-N per kg N.

The following table shows the resulting implied emission factors for NH3 -N and NO-N. NOx emissions are related to NO-N emissions by the ratio of 46/14. This relationship also holds for NO-N and NOx emission factors.

Table 3: IEF for NH3 -N and NO-N emissions from storage of digested energy crops

1990 1995 2000 2005 2010 2015 2016 2017 2018 2019 2020 2021 2022
IEF in kg NH3-N per kg N in digested energy crops 
0.0252 0.0240 0.0228 0.0212 0.0146 0.0090 0.0086 0.0083 0.0079 0.0075 0.0071 0.0067 0.0067
IEF in kg NO-N per kg N in digested energy crops 
0.00050 0.00048 0.00045 0.00042 0.00029 0.00018 0.00017 0.00016 0.00016 0.00015 0.00014 0.00013 0.00013

Trend discussion for Key Sources

NH3 and NOx from storage of anaerobically digested energy crops are no key source.

Recalculations

All time series of the emission inventory have completely been recalculated since 1990.

The following table shows the effects of recalculations on NH3 and NOx emissions from storage of anaerobically digested energy crops.

Differences to last year’s submission occur in all years and due to the update of activity data (see main page of the agricultural sector, Chapter 5 - NFR 3 - Agriculture (OVERVIEW), recalculation No. 13). For further details on recalculations see Vos et al. (2024), Chapter 1.3.

Table 4 - REC-1: Revised NH3 and NOx emissions, in kilotonnes

1990 1995 2000 2005 2014 2015 2016 2017 2018 2019 2020 2021 2022
Ammonia
current submission 0.0015 0.0180 0.1482 1.1624 3.2281 3.2124 3.0579 2.8835 2.7108 2.5822 2.5074 2.3137 2.3137
previous submission 0.0015 0.0190 0.1563 1.2267 3.2814 3.3428 3.3004 3.2741 3.2013 3.1419 3.1782 3.1782
absolute change 0.00 0.00 -0.01 -0.06 -0.05 -0.13 -0.24 -0.39 -0.49 -0.56 -0.67 -0.86
relative change [%] -5.19 -5.19 -5.19 -5.24 -1.62 -3.90 -7.35 -11.93 -15.32 -17.81 -21.11 -27.20
Nitrogen oxides
current submission 0.0001 0.0010 0.0080 0.0624 0.1733 0.1725 0.1642 0.1548 0.1455 0.1386 0.1346 0.1242 0.1242
previous submission 0.0001 0.0010 0.0084 0.0659 0.1762 0.1795 0.1772 0.1758 0.1719 0.1687 0.1706 0.1706
absolute change 0.00 0.00 0.00 0.00 0.00 -0.01 -0.01 -0.02 -0.03 -0.03 -0.04 -0.05
relative change [%] -5.19 -5.19 -5.19 -5.24 -1.62 -3.90 -7.35 -11.93 -15.32 -17.81 -21.11 -27.20

For pollutant-specific information on recalculated emission estimates for Base Year and 2021, please see the tables following chapter 8.1 - Recalculations.

Uncertainty

Details are described in chapter 1.7.

1)
Vos C, Rösemann C, Haenel H-D, Dämmgen U, Döring U, Wulf S, Eurich-Menden B, Freibauer A, Döhler H, Steuer B, Osterburg B, Fuß R (2024) Calculations of gaseous and particulate emissions from German agriculture 1990 – 2022: Report on methods and data (RMD) Submission 2024. www.eminv-agriculture.de