1.A3.b ii - Transport: Road Transport: Light Duty Vehicles

In sub-category 1.A.3.b ii - Road Transport: Light Duty Vehicles emissions from fuel combustion in Light Duty Vehicles (LDVs) are reported.

Specific consumption data for light-duty vehicles (LDV) are generated within TREMOD ¹⁾. - The following table provides an overview of annual amounts of fuels consumed by LDV in Germany.

Table 1: Annual fuel consumption of light duty vehicles, in terajoules

Table 2: Annual mileage of electric light-duty vehicles, as of 2012, in [km]

The majority of emission factors for exhaust emissions from road transport are taken from the 'Handbook Emission Factors for Road Transport' (HBEFA, versions 4.1 and 4.2) ²⁾,³⁾ where they are provided on a tier3 level mostly and processed within TREMOD ⁴⁾.

However, it is not possible to present these highly specific tier3 values here in a comprehendible way .

For heavy-metal (other then lead from leaded gasoline) and PAH exhaust-emissions, default emission factors from the 2023 EMEP/EEA Guidebook (EMEP/EEA, 2023), Table 3-86 have been applied ⁵⁾ (see super-ordinate chapter here ).

Regarding PCDD/F, tier1 EF from (Rentz et al., 2008) ⁶⁾ are used instead.

The following table provides an overview of the EF. Please note, that the values for heavy-metal (in [g/TJ]) and PAH (in [mg/TJ]) exhaust-emissions have been estimated from the EMEP/EEA defaults provided in [ppm/wt].

Table 3: Overview of tier1 EF applied for heavy metals and POPs exhaust-emissions

¹ values differ from EFs applied for fossil diesel oil to take into account the specific NCV of biodiesel
² no specific default available from ⁷⁾; value derived from CNG powered busses
³ no specific default available from ⁸⁾; values available for CNG also applied for biogas
⁴ no specific default available from ⁹⁾; value derived from LPG powered passenger cars

Table 4: Outcome of Key Category Analysis

NO_x emissions increased steadily until 2002 following the shift to diesel engines. During the last ten years, emissions decline steadily due to catalytic-converter use and engine improvements resulting from ongoing tightening of emissions laws and improved fuel quality.

As for the entire road transport sector, the trends for sulphur dioxide and ammonia exhaust emissions from passenger cars show charcteristics very different from those shown above.

Here, the strong dependence on increasing fuel qualities (sulphur content) leads to an cascaded downward trend of emissions, influenced only slightly by increases in fuel consumption and mileage.

For ammonia emissions the increasing use of catalytic converters in gasoline driven cars in the 1990s lead to a steep increase whereas both the technical development of the converters and the ongoing shift from gasoline to diesel cars resulted in decreasing emissions in the following years.

Starting in the middle of the 1990s, a so-called “diesel boom” began, leading to a switch from gasoline to diesel powered passenger cars. As the newly registered diesel cars had to meet the EURO2 standard (in force since 1996/'97) with a PM limit value less than half the EURO1 value, the growing diesel consumption was overcompensated qickly by the mitigation technologies implemented due to the new EURO norm. During the following years, new EURO norms came into force.

With the still ongoing “diesel boom” those norms led to a stabilisation (EURO3, 2000/'01) of emissions and to another strong decrease of PM emissions (EURO4, 2005/'06), respectively. Over-all, the increased consumption of diesel in passenger cars was over-estimated by the implemented mitigation technologies.

Compared to submission 2024, activity data have only been revised for 2022 and 2023.

Table 4: Revised fuel consumption data, in terajoules

Due to the variety of tier3 emission factors applied, it is not possible to display any changes in these data sets in a comprehendible way.

Besides a routine revision of the underlying model, no specific improvements are planned.