1.A.4.b ii - Residential: Household and Gardening: Mobile

Last updated on 20 Mar 2020 10:24 (cf. Authors)

Short description

Under sub-category 1.A.4.b ii - Residential: Mobile Sources in Households and Gardening fuel combustion activities and resulting emissions from combustion engine driven devices such as motor saws and lawn mowers are being reported.

NFR-Code Source category Method AD EF Key Category 1
1.A.4.b ii Residential: Household and Gardening: Mobile T1 NS, M CS, D L/T: CO
Lawnmower.PNG

Method

Activity data

Activity data are taken from annual fuel delieveries data provided in line 66: 'Households' of the National Energy Balances (NEB) for Germany (AGEB, 2019) [1].

Table 1: Sources for consumption data in 1.A.4.b ii
Relevant years Data Source
through 1994 AGEB - National Energy Balance, line 79: Households
since 1995 AGEB - National Energy Balance, line 66: Households

Here, given the rare statistics on sold machinery, these activity data is of limited quality only (no annual but cascaded trend).

As the NEB only provides primary activity data for total biomass used in 'households', but does not distinguish into specific biofuels, consumption data for bioethanol used in NFR 1.A.4.b ii are calculated by applying Germany's official annual shares of biogasoline blended to fossil gasoline.

Please note: Data on gasoline used in households as provided in the National Energy Balances represents a "residual item" following the allocation of the majority of this fuel to road and military vehicles.
Here, fuel sales to road vehicles might also include gasoline acquired on filling stations but used for household equipment.

Due to these reasons, activity data for gasoline consumption in households machinery and, hence, several emission estimates show no realistic trend but a stepwise development with significant jumps.

Table 2: Annual over-all fuel deliveries to residential mobile sources, in terajoules
1990 1995 2000 2005 2010 2011 2012 2013 2014 2015 2016 2017 2018
gasoline 2,177 2,395 2,395 2,395 3,379 4,069 3,995 3,720 3,946 4,228 4,228 4,228 4,070
biogasoline 0 0 0 16 131 167 177 159 172 183 184 178 183
Ʃ 1.A.4.b ii 2,177 2,395 2,395 2,411 3,510 4,236 4,172 3,879 4,118 4,411 4,412 4,406 4,253

source: AGEB, 2019 [1] and TREMOD MM [2]

These primary activity data can be distributed onto 2- and 4-stroke engines used in households via annual shares from Knörr et al. (2019b) [2].

Table 3: Annual shares of 2- and 4-stroke engines
1990 1995 2000 2005 2010 2011 2012 2013 2014 2015 2016 2017 2018
2-stroke 72% 50% 34% 31% 27% 27% 26% 25% 25% 24% 24% 24% 24%
4-stroke 28% 50% 66% 69% 73% 73% 74% 75% 75% 76% 76% 76% 76%
TOTAL 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100% 100%

source: TREMOD MM [2]

Table 4: Resulting estimates for fuel consumption in 2- and 4-stroke engines, in terajoules
1990 1995 2000 2005 2010 2011 2012 2013 2014 2015 2016 2017 2018
2-stroke engines
gasoline 1,563 1,204 803 749 920 1,084 1,019 923 968 1,027 1,018 1,010 966
biogasoline 0 0 0 5 36 44 45 40 42 45 44 43 43
4-stroke engines
gasoline 614 1,191 1,592 1,646 2,459 2,985 2,976 2,797 2,978 3,201 3,210 3,218 3,104
biogasoline 0 0 0 11 95 122 132 120 129 139 139 136 140
Ʃ 1.A.4.b ii 2,177 2,395 2,395 2,411 3,510 4,236 4,172 3,879 4,118 4,411 4,412 4,406 4,253

Emission factors

The emission factors used here are of rather different quality:
For all main pollutants, carbon monoxide and particulate matter, annually changing values computed within TREMOD-MM (Knörr et al. (2019b)) [2] are used, representing the development of mitigation technologies and th effect of fuel-quality legislation.

Here, as no such specific EF are available for biofuels, the values used for gasoline are applied to bioethanol, too.

For lead (Pb) from leaded gasoline and corresponding TSP emissions, additional emissions are are calculated from 1990 to 1997 based upon contry-specific emission factors from [2].)

Table 5: Annual country-specific emission factors from TREMOD MM1, in kg/TJ
1990 1995 2000 2005 2010 2011 2012 2013 2014 2015 2016 2017 2018
4-stroke machinery
NH3 1 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09 0.09
NMVOC - exhaust 1,2 727 819 809 781 774 771 769 768 766 765 764 764 763
NMVOC - evaporation 1,3 475 1,289 1,604 1,634 1,632 1,632 1,632 1,632 1,633 1,633 1,633 1,633 1,633
NOx 1 51.0 85.3 103 108 121 124 126 128 130 132 134 135 136
SOx 1 10.1 8.3 3.2 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37 0.37
BC 2.5 0.31 0.27 0.24 0.23 0.24 0.25 0.25 0.25 0.26 0.26 0.26 0.26 0.26
PM 2.4 6.29 5.46 4.85 4.63 4.87 4.94 5.00 5.06 5.11 5.15 5.19 5.22 5.24
CO 1 39,998 32,154 28,346 27,235 28,035 28,317 28,584 28,827 29,042 29,222 29,366 29,473 29,544
2-stroke machinery
NH3 1 0.07 0.07 0.07 0.07 0.07 0.08 0.08 0.08 0.09 0.09 0.09 0.09 0.09
NMVOC - exhaust 1,2 5.962 5.692 5.537 5.439 5.372 4.894 3.898 3.270 3.115 2.969 2.835 2.716 2.613
NMVOC - evaporation 1,3 1,387 1,129 510 394 290 299 317 329 334 338 342 346 349
NOx 1 23.5 28.6 37.4 53.9 63.5 61.6 57.0 55.0 56.0 56.9 57.7 58.3 58.9
SOx 1 10.1 8.3 3.2 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4
BC 2.4 5.14 4.79 4.76 4.76 4.80 4.95 5.25 5.45 5.53 5.60 5.67 5.73 5.78
PM 2,5 103 95.8 95.3 95.2 96.1 99.0 105 109 111 112 113 115 116
CO 1 25,505 22,501 16,571 15,061 13,624 13,963 14,734 15,251 15,423 15,593 15,757 15,909 16,045
4- and 2-stroke machinery
TSP6 2.35 0.82
Pb6 1,471 516

1 due to lack of better information: similar EF are applied for fossil and biofuels
2 from fuel combustion
3 from gasoline evaporation
4 EF(PM2.5) also applied for PM10 and TSP (assumption: > 99% of TSP consists of PM2.5)
5 estimated via a f-BC 0.05 as provided in [3], Chapter 1.A.2.g vii, 1.A.4.a ii, b ii, c ii, 1.A.5.b i - Non-road, note to Table 3-1: Tier 1 emission factors for off-road machinery
6 from leaded gasoline (until 1997)

NOTE: For the country-specific emission factors applied for particulate matter, no clear indication is available, whether or not condensables are included.

For information on the emission factors for heavy-metal and POP exhaust emissions, please refer to Appendix 2.3 - Heavy Metal (HM) exhaust emissions from mobile sources and Appendix 2.4 - Persistent Organic Pollutant (POP) exhaust emissions from mobile sources.

Discussion of emission trends

NFR 1.A.4.b ii is no key source.

Given the limited quality of gasoline-deliveries data from NEB line 66, the following emission trends are of limited significance only.

Unregulated pollutants (NH3, HMs, POPs, …)

For all unregulated pollutants, emission trends directly follow the trend in fuel consumption.

Here, as the emission factors for heavy metals (and POPs) are derived from tier1 default values, the emission's trend is stronlgy influenced by the share of 2-stroke gasoline fuel (containing lube oil with presumably higher HM content) consumed.

Regulated pollutants

Nitrogen oxides (NOx), Sulphur dioxide (SO2)

For all regulated pollutants, emission trends follow not only the trend in fuel consumption but also reflect the impact of fuel-quality and exhaust-emission legislation.

Particulate matter (BC, PM2.5, PM10, and TSP)

Over-all PM emissions are by far dominated by emissions from diesel oil combustion with the falling trend basically following the decline in fuel consumption between 2000 and 2005.
Nonetheless, the decrease of the over-all emission trend was and still is amplified by the expanding use of particle filters especially to eliminate soot emissions.

Additional contributors such as the impact of TSP emissions from the use of leaded gasoline (until 1997) have no significant effect onto over-all emission estimates.

Here, as the EF(BC) are estimated via fractions provided in [3], black carbon emissions follow the corresponding emissions of PM2.5.

Recalculations

As all emission factors remain unchanged, recalculations occur only for 2017, resulting from the application of activity data from the now finalised National Energy Balance 2017.

Table 7: Revised total inland fuel deliveries 2017 for household-related consumption, in terajoules
gasoline biogasoline
total 2-stroke 4-stroke total 2-stroke 4-stroke
Submission 2020 4,228 1.010 3,218 178 42.6 135.7
Submission 2019 4,228 1.010 3,218 180 43.0 137.0
absolute change 0 0 0 -2 -0.4 -1.3
relative change 0.00% 0.00% 0.00% -0.96% -0.98% -0.96%

For specific information on recalculated emission estimates for Base Year and 2017, please see the pollutant specific recalculation tables following chapter 8.1 - Recalculations.

Uncertainties

Uncertainty estimates for activity data of mobile sources derive from research project FKZ 360 16 023 (Knörr et al. (2009)) [5]: "Ermittlung der Unsicherheiten der mit den Modellen TREMOD und TREMOD-MM berechneten Luftschadstoffemissionen des landgebundenen Verkehrs in Deutschland".

Uncertainty estimates for emission factors were compiled during the PAREST research project. Here, the final report has not yet been published.

Planned improvements

Besides a routine revision of the TREMOD MM model, no specific improvements are planned at the moment.

FAQs

Why are similar EF applied for estimating exhaust heavy metal emissions from both fossil and biofuels?

The EF provided in [4] represent summatory values for (i) the fuel's and (ii) the lubricant's heavy-metal content as well as (iii) engine wear. Here, there might be no heavy metal contained in biofuels. But since the specific shares of (i), (ii) and (iii) cannot be separated, and since the contributions of lubricant and engine wear might be dominant, the same emission factors are applied to biodiesel and bioethanol.


Bibliography
1. AGEB, 2019: Working Group on Energy Balances (Arbeitsgemeinschaft Energiebilanzen (Hrsg.), AGEB): Energiebilanz für die Bundesrepublik Deutschland; URL: http://www.ag-energiebilanzen.de/7-0-Bilanzen-1990-2017.html, (Aufruf: 29.10.2019), Köln & Berlin, 2019.
2. Knörr et al. (2019b): Knörr, W., Heidt, C., Gores, S., & Bergk, F.: ifeu Institute for Energy and Environmental Research (Institut für Energie- und Umweltforschung Heidelberg gGmbH, ifeu): Aktualisierung des Modells TREMOD-Mobile Machinery (TREMOD MM) 2019, Heidelberg, 2019.
3. EMEP/EEA, 2019: EMEP/EEA air pollutant emission inventory guidebook – 2019, Copenhagen, 2019.
4. Rentz et al., 2008: Nationaler Durchführungsplan unter dem Stockholmer Abkommen zu persistenten organischen Schadstoffen (POPs), im Auftrag des Umweltbundesamtes, FKZ 205 67 444, UBA Texte | 01/2008, January 2008 - URL: http://www.umweltbundesamt.de/en/publikationen/nationaler-durchfuehrungsplan-unter-stockholmer
5. Knörr et al. (2009): Knörr, W., Heldstab, J., & Kasser, F.: Ermittlung der Unsicherheiten der mit den Modellen TREMOD und TREMOD-MM berechneten Luftschadstoffemissionen des landgebundenen Verkehrs in Deutschland; final report; URL: https://www.umweltbundesamt.de/sites/default/files/medien/461/publikationen/3937.pdf, FKZ 360 16 023, Heidelberg & Zürich, 2009.
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