2.G.4 - Use of Lubricants

Short description

In source category 2.G.4 - Other Product Use: Lubricants, emissions from both stationary and mobile application of lubricants are reported.

Category Code Method AD EF
2.G.4 T1, T2 NS, M CS, D
covering emissions from:
use of lubricants in stationary applications T2 NS CS
use of lubricants in mobile applications T1 NS, M D

Click to view Legend

Click to hide Legend

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 L/T NA NA NA NA NA NA NA -/- NA

Click to view Legend

Click to hide Legend

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

Use of lubricants in stationary applications

Method

This sub-category comprises the entire use phase including the process stages of input and output. The products or lubricants covered here, are:

  • Compressor oils
  • Turbine oils
  • Gear oils (automotive oils including automatic transmission fluids, industrial-gear oils)
  • Hydraulic oils
  • Insulating oils
  • Machine oils
  • Process oils
  • Other industrial oils not for lubricating purposes
  • Metal working fluids fluids (hardening oils, water-miscible and not water-miscible metal working fluids, anticorrosive oils)
  • Greases
  • Base oils
  • Extracts from lubricant refining

2-stroke engine oils are excluded here as they are considered to be part of the 2-stroke fuel and are therefore burned intentionally in 2-stroke engines as applied in road vehicles (mopeds) and other mobile machinery (chainsaws, lawn mowers etc.). In contrast, emissions from the unintended co-incineration of lubricants in mobile machinery and vehicles are reported in Use of lubricants in mobile applications.

‘NMVOC’ is defined in keeping with the VOC definition found in the EC solvents directive. For purposes of the definition of solvents, the term ‘solvent use’ is also defined in keeping with the EC solvents directive.

The consumption of lubricants in Germany has remained at a relatively constant level since 1990, apart from a sharp decrease in the crisis years 2009 and 2020. In 2022 the consumption of lubricants falls to the margin of 588456 t after a slight rebound in 2021.

Activity data

The emissions calculation method follows a Tier-2 approach. It uses national statistical data [Lit. 1] for the quantities placed on the market specific per lubricant types as activity rate and specific emission factors for each lubricant type. It is assumed that the amount of lubricants placed on the market per year equals the lubricant use (consumption) in the same year.

Emission factors

Along the life cycle of the different lubricant types, different kinds of losses occur. Only some types of losses are of relevance with regard to air emissions and the different lubricants types differ significantly from each other. Relevant emitted pollutants identified for lubricants are NMVOC and CO2. But only for engine oils used in machinery and in vehicles emission of both could be accounted for due to combustion of a small fraction of lubricating oils directly resulting in CO2 emissions.

For Insulating oils [Lit. 3, 5], Process oils [Lit. 4, 10, 11], Greases [Lit. 10, 11] and Extracts from lubricant production [Lit. 2, 10, 11] no emissions expected.

All emission factors are are constant in the entire time series. They were determined in a research project (UBA, 2018) [Lit. 14].

Table 1: Tier 2 emission factors for specific lubricant-type groups in percent

NMVOC
Lubricant-type group Proportion range of total sales since 1990 Default Range Reference
Compressor oils =< 1 % 1.5 % 1 - 2 % [Lit. 2 - 7]
Turbine oils < 1 % 0.5 % 0 - 1 % [Lit. 2, 3, 5]
Automotive gear oils 5 - 10 % 1 % 0 - 2 %
Industrial gear oils 2 - 3 % 1.5 % 1 - 2 %
Hydraulic oils 6 - 15 % 1.5 % 1 - 2 %
Machine oils 1 - 7 % 2.5 % 0 - 5 % [Lit. 2, 5, 9]
Other oils not for lubricating purposes 2 - 7 % 25 % 0 - 50 % [Lit. 3, 10 - 12]
Metalworking fluids 5 - 9 % 5 % 0 - 10 % [Lit. 2, 4, 13]
Base oils 4 - 16 % 10 % 5 - 15 % [Lit. 14]

In 1995 four categories fell away/ceased to exist (Table 2) and three type groups were newly introduced due to modifications/changes in the Mineral Oil Statistics concerning lubricants. A slight adjustment of the procedure for the years 1990-1994 was needed. Table 2 shows the affected categories as well as the ways in which they were handled in the calculation procedure.

Table 2: Handling of categories in the Mineral Oil Statistics, 1990-1994

Category Remarks concerning the procedure NMVOC emission factor
Other lubricating oils, specialty and other lubricating oils, non-specialty These are handled like the “machine oils” group, which is lacking in the 1990-1994 period. This group includes various specialty and non-specialty libricationg oils. 2.5 %
Other mineral oils for special applications This category contains no lubricating oils. It is handled like the category “Other industrial oils not used for lubrication” which is lacking in the 1990-1994 period. 25 %
Light-coloured plasticisers and extender oils Extender oils and plasticisers are classified with the process oils. They are handled accordingly. 0 %
Uncertainties

For activity data, an uncertainty of 5 percent is assumed considering the well developed national statistics.

The emission factors are based on a broad review of literature and results from relevant research projects and have been discussed with senior lubricant experts. The experts suggested using ranges which are provided in the emission factor table 1.

The modifications of the Mineral Oil Statistics in 1995 show no impact of overall amount of lubricants. Only a reclassification of lubricants from unspecified application categories to specified application categories was made. The emissions for the years 1990-1994 could therefore be just up to 25% to high.

Recalculations

With activity data and emission factors remaining unrevised, no recalculations were carried out compared to the previous submission.

Planned improvements

No category-specific improvements are planned.

Bibliography

Lit. 1: Official Mineral-oil Data (amtliche Mineralöldaten) of the Federal Office of Economics and Export Control (BAFA).)
Lit. 2: Ökopol. Consultation of different senior lubricant experts and manufacturers: Hamburg, 2017.)
Lit. 3: Zimmermann, T.; Jepsen, D. Return rates for used lubricant oils in Belgium: Study on Waste Oil Return in Belgium; Ökopol, 2017.)
Lit. 4: Jepsen, D.; Zimmermann, T.; Sander, K.; Wagner, J. Erhebung der Struktur des Altölsammelmarktes und Optimierungspotenziale für bessere Altölqualitäten im Kontext der Abfallhierarchie; Hg. v. Umweltbundesamt (UBA). Ökopol: Dessau-Roßlau, 2016.)
Lit. 5: Sander, K.; Jepsen, D.; Zangl, S.; Schilling, S. Stoffstrom- und Marktanalyse zur Sicherung der Altölentsorgung. Forschungsbericht 204 31 32 UBA-FB 000883: Dessau-Roßlau, 2006.)
Lit. 6: Kline & Company. Lubricant Consumption and Used Oil Generation in California: A Segmented Market Analysis: Part II: Collectable Used Oil Availability in California, 2000-2011. published 03/03/2015: Sacramento, CA, USA, 2012.)
Lit. 7: UNEP. Compendium of Recycling and Destruction Technologies for Waste Oils: Osaka, Japan, 2012.)
Lit. 8: VSI. Getriebeöle; https://www.vsi-schmierstoffe.de/index.php.)
Lit. 9: Vidal-Abarca, G. C.; Kaps, R.; Oliver, W.; Escamilla, M.; Josa, J.; Riera, M. R.; Benedicto, E. Revision of European Ecolabel Criteria for Lubricants. Preliminary Report: Sevilla, 2016.)
Lit. 10: Möller, U. J. Altölentsorgung durch Verwertung und Beseitigung; Kontakt & Studium Bd. 253; Expert Verlag: Renningen, 2004.)
Lit. 11: Bartz, W. J.; Springer, G.; Blanke, H.-J. Expert Praxislexikon Tribologie Plus: 2010 Begriffe für Studium und Beruf, 2., völlig neubearb. Aufl. des Lexikons der Schmierungstechnik von G. Vögtle; Expert Verlag: Renningen, 2000.)
Lit. 12: VSI. Grundöle; https://www.vsi-schmierstoffe.de/index.php.)
Lit. 13: Kolshorn, K.-U.; Wiesert, P.; Götz, R.; Rippen, G. Ermittlung von Altölvermeidungspotentialen: UBA-Forschungsvorhaben Nr. 103 60 111; Trischler und Partner GmbH: Darmstadt, 1996.)
Lit. 14: UBA, 2018: Zimmermann, T.; Jepsen, D. (2018) Entwicklung von Methoden zur Berechnung von Treibhausgas- und Luftschadstoffemissionen aus der Verwendung von Schmierstoffen und Wachsen.)


Use of lubricants in mobile applications

In sub-category 2.D.3.i - Other product use: Use of lubricants in mobile applications, the German air pollutant emisisons inventory includes emissions from the unintentional co-incineration of lubricants in mobile sources.

As emissions from the use of lubricants in stationary machinery result mostly from the evaporation whereas emissions from mobile machinery result mostly from the unintentional co-incineration within the engine, the methods for emission calculation differ widely.

Therefore, the approaches for estimating emissions from these two areas of lubricant application are looked at in separate sub-chapters linked below.

Methodology

Activity data

Basically, the amounts of lubricants unintentionally co-incinerated in engines other than 2-strokes is estimated from the annual amounts of fuels used in these engines, excluding the amounts of fuels used for international aviation and navigation.

Here, the majority of lubricant co-incineration takes place in road vehicles. These related amounts of co-incinerated lubricants are calculated directly within TREMOD 1).

Table 1: Annual amounts of lubricants co-incinerated in mobile vehicles and machinery - excluding 2-stroke engines, in terajoules

1990 1995 2000 2005 2010 2015 2016 2017 2018 2019 2020 2021 2022
1,400 1,601 1,713 1,757 1,804 1,922 1,951 1,977 1,985 1,999 1,770 1,778 1,812

source: own estimations and TREMOD 2)

The emission factors are derived from chapter 1.A.3.b.i-iv Road transport 2019, Table 3-87 of the EMEP/EEA air pollutant emission inventory guidebook 2019 3).

These default values were transferred via a NCV of 0.03985 GJ/kg into the following energy-related values:

Table 2: tier1 emission factors for heavy-metal emissions from co-incinerated lubricants, in g/TJ

As Cd Cr Cu Hg Ni Pb Se Zn
0.00 114 482 19,523 0.00 800 0.81 114 11,297

With default emission factors applied, emissions' trends depend solely on the amounts of unintentionally co-incinerated lubricants (see Table 1).

Table 3: Annual heavy-metal emissions from co-incinerated lubricants, in metric tonnes

1990 1995 2000 2005 2010 2015 2016 2017 2018 2019 2020 2021 2022
As NA
Cd 0.16 0.18 0.20 0.20 0.21 0.22 0.22 0.23 0.23 0.23 0.20 0.20 0.21
Cr 0.67 0.77 0.83 0.85 0.87 0.93 0.94 0.95 0.96 0.96 0.85 0.86 0.87
Cu 27.3 31.3 33.4 34.3 35.2 37.5 38.1 38.6 38.8 39.0 34.6 34.7 35.4
Hg NA
Ni 1.12 1.28 1.37 1.41 1.44 1.54 1.56 1.58 1.59 1.60 1.42 1.42 1.45
Pb 0.0011 0.0013 0.0014 0.0014 0.0015 0.0016 0.0016 0.0016 0.0016 0.0016 0.0014 0.0014 0.0015
Se 0.16 0.18 0.20 0.20 0.21 0.22 0.22 0.23 0.23 0.23 0.20 0.20 0.21
Zn 15.8 18.1 19.3 19.9 20.4 21.7 22.0 22.3 22.4 22.6 20.0 20.1 20.5

Recalculations

Activity data (annual amounts of unintentionally co-incinerated lubricants) have been revised slightly for the entire time series.

Table 4: Revised annual amounts of unintentionally co-incinerated lubricants, in terajoules

1990 1995 2000 2005 2010 2015 2016 2017 2018 2019 2020 2021
current submission 1,400 1,601 1,713 1,757 1,804 1,922 1,951 1,977 1,985 1,999 1,770 1,778
previous submission 1,400 1,601 1,713 1,746 1,792 1,916 1,946 1,971 1,977 1,990 1,765 1,745
absolute change 0.14 0.04 0.08 11.1 11.3 6.23 5.27 5.47 8.33 8.54 4.86 32.9
relative change 0.01% 0.00% 0.00% 0.64% 0.63% 0.33% 0.27% 0.28% 0.42% 0.43% 0.28% 1.88%

On the other hand, the tier1 emission factors applied so far, remain unaltered compared to last year's submission.

Therefore, the canges in the emission estimates reported for this sub-category result solely from the named revisions in activity data.

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

Planned improvements

Although there are no improvements planned for this specific sub-category, several routine model revisions are scheduled for mobile sources with impact on fuel consumption data and, hence, the amounts of unintentionally co-incinerated lubricants.

4). 5)


1), 2), 4) Knörr et al. (2023a): Knörr, W., Heidt, C., Gores, S., & Bergk, F.: ifeu Institute for Energy and Environmental Research (Institut für Energie- und Umweltforschung Heidelberg gGmbH, ifeu): Fortschreibung des Daten- und Rechenmodells: Energieverbrauch und Schadstoffemissionen des motorisierten Verkehrs in Deutschland 1960-2035, sowie TREMOD, im Auftrag des Umweltbundesamtes, Heidelberg & Berlin, 2023.
3), 5) EMEP, 2019: EMEP/EEA air pollutant emission inventory guidebook 2019, URL: https://www.eea.europa.eu/publications/emep-eea-guidebook-2019/part-b-sectoral-guidance-chapters/1-energy/1-a-combustion/1-a-3-b-i/view; Copenhagen, 2019.