Appendix 2.2 - Additional Methodological Information: Road Transport

Last updated on 29 Aug 2019 09:29 (cf. Authors)

Derivation of activity rates

Cross-check with Energy Balance

The Energy Balance is also used to model transport-quantity structures in TREMOD. For example, the German Economic Institute (DIW) carries out a fuel-consumption calculation in order to derive total mileage travelled (DIW, 2002). Some of the results of the calculation, for automobile transports, are entered into TREMOD. The DIW uses a fuel-consumption calculation in order to determine total domestic mileage; TREMOD uses some other sources and assumptions to estimate total domestic mileage – especially for goods transports (cf. the detailed description in (Knörr, W., Höpfner, U., & Lambrecht, U. (2002)) [1]). This estimate also takes the basic figures of the Energy Balance into account.

On the other hand, due to the many dependencies and uncertainties in the model, and to the basic data that must be taken into account, no feasible means is available for comparing mileage and energy consumption, for each year and each vehicle layer, in such a manner that the results yield the Energy Balance sum and the mileage and average energy consumption figures in the time series are plausible. For this reason, the TREMOD results for the fuel consumption are corrected, at the end of the process, in such a manner that the total for each reference year corresponds to the relevant figure in the Energy Balance.

Since TREMOD calculates fuel consumption in tonnes, the results first have to be converted into terajoule [TJ]. For this purpose the net calorific values of the Working Group on Energy Balances (AGEB) are used.

Table 1: Net calorific values for gasoline and diesel oil
Year Gasoline Diesel Oil
1990-1992 43.543 MJ/kg 42.704 MJ/kg
since 1993 43.543 MJ/kg 42.960 MJ/kg

Source: Working Group on Energy Balances (Arbeitsgemeinschaft Energiebilanzen)

The correction factors are derived in TREMOD separately for the various vehicle categories, as follows:

  • Firstly, a correction factor for gasoline is derived from the calculated petrol consumption for all vehicle categories and from petrol sales pursuant to the Energy Balance.
  • The correction factor for gasoline is then also used to bring fuel consumption of vehicles with diesel engines, among automobiles and other vehicles ≤ 3.5 t (light duty vehicles (LDV), and of motor homes and motorcycles (MC)), in line with the Energy Balance.
  • The difference between the corrected diesel-fuel consumption of automobiles and of other vehicles ≤ 3.5 t and the Energy Balance is then allocated to heavy duty vehicles and busses.
  • The correction factor for heavy duty vehicles and busses is then calculated from their energy consumption, as calculated in accordance with the domestic principle, and the pertinent difference, as calculated for this group, from the Energy Balance.
Table 2: Correction factors for adjustment of TREMOD estimates to the National Energy Balance
Gasoline Diesel oil
(incl. Bioethanol) (incl. Biodiesel)
Area PC, LDV, 2W PC, LDV HDV, Bus
1990 OGL 1.035 1.035 1.126
1990 NGL 1.051 1.051 1.390
1991 OGL 1.032 1.032 1.084
1991 NGL 1.050 1.050 0.983
1992 OGL 1.035 1.035 1.166
1992 NGL 0.990 0.990 1.169
1993 OGL 1.039 1.039 1.277
1993 NGL 0.970 0.970 1.126
1994 OGL 0.981 0.981 1.181
1994 NGL 0.981 0.981 1.181
1995 G 0.993 0.993 1.205
1996 G 0.994 0.994 1.183
1997 G 0.991 0.991 1.186
1998 G 0.984 0.984 1.247
1999 G 0.987 0.987 1.305
2000 G 0.957 0.957 1.334
2001 G 0.944 0.944 1.236
2002 G 0.939 0.939 1.193
2003 G 0.926 0.926 1.134
2004 G 0.933 0.933 1.080
2005 G 0.923 0.923 1.074
2006 G 0.921 0.921 1.090
2007 G 0.918 0.918 1.032
2008 G 0.919 0.919 1.021
2009 G 0.913 0.913 1.056
2010 G 0.902 0.902 1.088
2011 G 0.913 0.913 1.060
2012 G 0.893 0.893 1.134
2013 G 0.916 0.916 1.147
2014 G 0.936 0.936 1.084
2015 G 0.904 0.904 1.143
2016 G 0.918 0.918 1.152
2017 G 0.927 0.927 1.170

Source: TREMOD 5.81 (Knörr, W. et al. (2018a)) [2]

Allocation of biofuels, petroleum and LPG to the structural elements

The Energy Balance lists data for biofuels, petroleum and LPG for the transport sector. For purposes of importing into the CSE, the results for these fuels are derived as follows:

  • Biodiesel is allocated to all structural elements with diesel engines, in keeping with their percentage shares of consumption of conventional diesel fuel.
  • Bioethanol is allocated to all structural elements with gasoline engines, in keeping with their percentage shares of consumption of conventional gasoline.
  • Petroleum is allocated to busses on roads outside of municipalities – and, thus, to the structural elements SV - BUS - KOAO and SV - BUS - MTAO – in keeping with their percentage shares of consumption of conventional diesel fuel.
  • LPG is allocated to conventional automobiles, with petrol engines, on municipal roads (CSE nomenclature: SV - PKWO - KOIO).

Activity rate for evaporation

The activity data for evaporation emissions is set as total gasoline consumption, on municipal roads, pursuant to TREMOD; the corresponding figure for mopeds is the total consumption. The values corrected for the Energy Balance are used.

Motor-vehicle-fleet data

For western Germany from 1990 through 1993, and for Germany as a whole as of 1994, car ownership was calculated on the basis of the officially published ownership and new registration statistics of the Federal Motor Transport Authority (KBA). The car ownership analysis for East Germany in 1990 was based on a detailed analysis of the Adlershof caremissions-testing agency in 1992 and the time series in the statistical annuals of the GDR. For the period between 1991 and 1993, it was necessary to estimate the figures with the aid of numerous assumptions.

Fleet data for the TREMOD model, for the reference years 2001 through 2003, are obtained from the database of the Federal Motor Transport Authority (KBA). The supplied data include vehicle fleets for each reference year, broken down as required for emissions calculation, i.e. in accordance with the following characteristics: type of engine (petrol, diesel, other), size class, vehicle age and emissions standard. For each reference year, the mid-year fleet is assumed to be representative of the fleet's composition for the year. The fleet figures for the years 2004 through 2007 were calculated with the help of a fleet-shifting module in TREMOD that extrapolates past fleet-growth trends.

Mileage

Mileage data were updated on the basis of the "2002 mileage survey" ("Fahrleistungserhebung 2002"; Institute of Applied Transport and Tourism Research (IVT, 2004 [3]), the "2005 road-transport census" "Straßenverkehrszählungen 2005"; Federal Highway Research Institute (BASt), 2007 [4]) and data on growth of transports on federal highways (BASt, 2008).

Shifting of fuel purchases to other countries

Because fuel prices in Germany are higher – significantly, in some cases – than in almost all of Germany's neighbours (Denmark is the only exception), for some time the fuels used in Germany have included fuels purchased in other countries and brought into the country as "grey" imports.

At present, no precise data are available on this phenomenon, which is significant for Germany's border regions and which is referred to as "refuelling tourism" ("Tanktourismus"). Although several detailed studies have been carried out, no reliable overall picture of the situation is yet available (cf. Lenk et al., 2004 [5]). The sources that have documented shifting of consumers' fuel purchases to other countries (along with the resulting negative impacts on neighbouring countries' own emissions inventories) have included a study published by the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW, 2005 [6]).

Emission factors

All emission factors are listed in the "Handbook Emission Factors for Road Transport 3.3" (Keller et al., (2007) [7]), a reference work prepared via co-operation, between the environmental protection agencies of Germany, Switzerland and Austria also supported by Sweden, Norway, France as well as the JRC (European Research Center of the European Commission), in derivation of emission factors for road traffic. The emission factors in the manual originate predominantly from the measurement programmes of TÜV Rheinland (TÜV, Technical Control Association) and RWTÜV. Those programmes have included fundamental surveys for the reference years 1989/1990. In those surveys, a new method was used, for both passenger cars and heavy duty vehicles, whereby emission factors were derived according to driving habits and the traffic situation. Within the context of field monitoring data, the passenger-car emission factors were updated for cars produced up to 1994. Version 3.3 of the "Emission-factor Manual for Road Transports" ("Handbuch der Emissionsfaktoren des Straßenverkehrs": HBEFA), which is used for the current emissions calculations, draws on findings of the EU working group COST 346 and the ARTEMIS research programme. The emission factors are derived from the development of the various vehicle layers and from the data provided by the HBEFA. The emissions reduction achieved via the introduction of sulphur-free fuels was estimated by the German Environment Agency.

Derivation of emission factors

Emission factors from TREMOD

In the CSE, emission factors for the "engines" ("Antrieb") category are listed in [kg/TJ], while those for the "Evaporation" category are given in [kg/t]. For gasoline, diesel oil, LPG and CNG, these values can be derived from TREMOD for all structural elements. To this end, emissions (in tonnes [t]) and energy consumption (in terajoules [TJ]; converted from the results "energy consumption in t", using the net calorific values) are derived from the TREMOD results and allocated to the relevant structural elements. The emission factor for each structural element then results as the quotient resulting from emissions, in tonnes per structural element, divided by the energy consumption, per structural element, in terajoule.

A similar procedure is used to obtain the emission factors for fugitive emissions, in [kg/consumption on municipal roads], in tonnes [t]). For purposes of this derivation, TREMOD results without correction to the Energy Balance are used, since such correction is already contained in the activity data for the CSE. Use of the corrected values (emissions and energy consumption) leads to the same results, however, since the correction factor cancels out in calculation of mean emission factors (emissions corrected / energy corrected = emissions uncorrected / energy uncorrected).

Emission factors for biodiesel, bioethanol, petroleum, Liquefied Petroleum Gas (LPG), and Compressed Natural Gas (CNG)

The emission factors for biodiesel and petroleum are set at the same values as those for conventional diesel fuel. The emission factors for bioethanol are set at the same values as those for conventional gasoline.

Exception:

  • The SO2 emission factor for petroleum is set to 24 kg/TJ for those years in which diesel fuel has a higher value. In all other years, the lower value for diesel fuel is used.

Derivation of data for western and eastern Germany, 1994

TREMOD distinguishes between old and new German Länder only until 1993. Since the CSE also requires such differentiation for 1994, a relevant breakdown must be made using simplifying assumptions. The framework conditions include:

  • The sum total of activity rates for engines (Antrieb) must correspond to the relevant Energy Balance values (in each case, old and new German Länder).
  • In the overall result, emissions resulting from linking activity rates with emission factors must correspond to the TREMOD results for Germany.
  • With these framework conditions, the present study can carry out a relevant breakdown only under the following assumptions:
  • The emission factors for old and new German Länder are set, for all structural elements, to the relevant values for all of Germany in 1994.
  • The structural elements' percentage shares of the activity rates, for each fuel, are considered to be the same in each case for the old and new German Länder, and they are the same as the relevant values for all of Germany in 1994.

With these assumptions, the aforementioned conditions are fulfilled. A third condition is not fulfilled, however: the plausibility of emissions results in the time series, in each case, for the old/new German Länder.


Bibliography
1. Knörr et al. (2002): Knörr, W., Höpfner, U., & Lambrecht, U. (2002): Aktualisierung des "Daten- und Rechenmodells": Energieverbrauch und Schadstoffemissionen des motorisierten Verkehrs in Deutschland 1980-2020 : Endbericht / Wolfram Knörr (Projektleiter): Heidelberg [u.a.] 2002.
2. Knörr et al. (2018a): 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 1960-2030, sowie TREMOD 5.81, im Auftrag des Umweltbundesamtes, Heidelberg & Berlin, 2018.
3. IVT, 2004: Institut für angewandte Verkehrs- und tourismusforschung e.V.: Fahrleistungserhebung 2002, Teil: Begleitung und Auswertung. Untersuchung im Auftrag der Bundesanstalt für Straßenwesen, Projektnummer FE 82.201/2001. Heilbronn/Mannheim.
4. BASt, 2007: Federal Highway Research Institute (Bundesanstalt für Straßenwesen, BASt): Unterreihe Verkehrstechnik; V 164: "Straßenverkehrszählung 2005: Ergebnisse", Thorsten Kathmann, Hartmut Ziegler, Bernd Thomas; 62 Seiten; Bergisch Gladbach, 2007
5. Lenk et. al (2004): Lenk, T., Vogelbusch, F., & Falken, C.: Auswirkungen des Tanktourismus auf das deutsche Steueraufkommen – eine finanzwissenschaftliche Bestandsaufnahme. Paper presented at the UNITI Bundesverband mittelständischer Mineralölunternehmen e. V. - Mitgliederversammlung 2004, München.
6. BMLFUW, 2005: Federal Ministry for Agriculture, Forestry, Environment and Water Management (Bundesministerium für Land- und Forstwirtschaft, Umwelt und Wasserwirtschaft): Abschätzung der Auswirkungen des Tanktourismus auf den Treibstoffverbrauch und die Entwicklung der CO2-Emissionen in Österreich.; Wien, 2005.
7. Keller et al., (2007): Keller, M., Hausberger, S., Matzer, C., Wüthrich, P., & Notter, B.: Handbuch für Emissionsfaktoren des Straßenverkehrs (HBEFA) Version 3.3. from MK Consulting GmbH, INFRAS AG & IVT / TU Graz; http://www.hbefa.net/d/documents/HBEFA33_Hintergrundbericht.pdf; http://www.hbefa.net/d/documents/HBEFA33_Documentation_20170425.pdf; Graz, 2017.
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License