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Methodology: LIPASTO unit emissions database

The following links help navigate the LIPASTO unit emission general description and mode-specific methodology descriptions.

 |  General |  Road transport  |  Rail transport |  Waterborne transport |  Air transport |  Working machines, etc. | 


Road transport

Introduction

There is a lot of information on energy consumption and emissions from road transport, which is why LIPASTO unit emission factors for road contains more than 10 000 figures. Publicly available information, that is based on real measurements, is nevertheless scarce as measurements are expensive. Road vehicle fleets renew fast compared to trains and ships. New emission regulations are also introduced in every couple of years or so. This is why unit emission factors for road are in dynamic change and it is important to use latest information.

The principle of the LIPASTO unit emission pages is to present emissions and energy consumption per passenger or net tonne of freight transported over one kilometre. Emissions are shown to empty and full freight vehicles as well as typical loads. Vehicles of different EURO classes are shown, but also an average vehicle is modelled if information of EURO class is not available. Highway driving and urban driving are very different modes of operation, and emission factors for these are given respectively. Typical combination of these in delivery driving is also modelled

Definitions

  • Gross vehicle mass means weight of the vehicle and payload capacity.
  • Pay load capacity means maximum freight weight.
  • Highway driving means average driving on Finnish public roads, taking into account average speeds.
  • Urban driving means average driving on streets, with journey speed of 30 km/h and about three stops per kilometre.
  • Emissions per vehicle kilometre (g/km) mean emissions of the vehicle per kilometre. All weight carried by the vehicle is included in computing emission factors, including e.g. weight of a container.
  • Passenger kilometre is the transport of one passenger over one kilometre. Passenger kilometres of a bus from point A to point B are calculated by multiplying the distance transported by the number of passengers. Emissions are caused also by an empty bus, even if passenger kilometres do not accumulate.
  • Emissions per passenger kilometre [g/pkm] means average emissions caused by one passenger over one kilometre. For passenger cars, the driver is included in passenger count.
  • Net load (net tonnes) means effective weight of the load. Weight of a container is not included but any fixed packaging is. The weight of e.g. a container, which contributes to amount of energy consumed, has been acknowledged in the weight of the vehicle when computing unit emissions.
  • Tonne kilometre means net tonnes of freight transported over one kilometre. Tonne kilometres of a trip are calculated by multiplying the distance transported by the weight of freight. Emissions are caused also by an empty trips, even if tonne kilometres do not accumulate.
  • Emissions per tonne kilometre [g/tkm] mean average emissions caused by one net tonne of freight over one kilometre.
  • Full load means maximum use of pay load capacity of a vehicle.
  • Emission standard means EURO classes of vehicles, which roughly correlates to vehicle production year.
  • Mileage share tables in the end of data tables are based on LIPASTO LIISA model. They show the share of vehicles of different age in the total mileage.
  • Average row in the bottom of each table means a weighted average (based on mileage share) of vehicles of different EURO classes. If information of EURO class is missing, this row can be used.
  • Gas driven vehicles are those using natural gas or bio gas as well as liquid fuel. It is important to know the share of driving on gas and on liquid fuel and calculate emissions accordingly.
  • Electric vehicles (battery electric vehicles, BEV) only have an electric engine and are emission free in the operational phase (driving).
  • Plug-in hybrid electric vehicles (PHEV) have both electric and combustion engine. Driving causes emissions only when using the combustion engine. Energy consumption and emissions of such a vehicle are calculated according to shares of driving using each engine.
  • Hybrids (mild and full) are vehicles that have both electric and combustion engine but cannot be charged with electricity. These are not considered as electric vehicles.

Sources of information

  1. Handbook Emission Factors for Road Transport Handbook Emission Factors for Road Transport (HBEFA). Umweltbundesamt Berlin (UBA) et al. Version 3.3 (25.4. 2017).
  2. VTT’s own measurements. Juhani Laurikko, (e-mail: name.lastname@vtt.fi).
  3. LIISA. VTT’s calculation model for road transport emissions.
  4. Information from ERMES (European Research Group on Mobile Emission Sources).
  5. Emissions for two-wheelers and microcars are based on VTT’s LIPASTO calculation sub-model MP-LIISA. It uses EMEP/EEA Emission inventory guidebook 2013. Motorcycles and mopeds use gasoline, whereas microcars use diesel.

Biofuels

In this section we discuss biofuels from the unit emission point of view. More information on the biofuel topic in general can be found e.g. by the Finnish Petroleum and Biofuels Association.

In transport biofuels can be used as such or blended with fossil fuels. The use phase carbon dioxide emissions from biofuels have been agreed to count as zero. The combustion of biofuels does of course result carbon dioxide emissions, but as they originate from biogenic materials (and not fossil resources) they are perceived to absorb into biogenic materials again in the so called carbon cycle. the production phase of biofuels may nevertheless cause other carbon dioxide emissions, but they are calculated not as transport emissions but as e.g. agricultural or energy production industry emissions. If transport emissions are calculated using life cycle assessment (LCA), both production phase and use phase emissions should be taken into account. Both these two phases are included in emission calculations using standard EN 16258.

There are numerous biofuel options available. The most typical are ethanol and renewable diesel, i.e. hydrotreated vegetable oil (e.g. NEXBTL by Neste). Blending ethanol with gasoline has technological limitations, and 98E5 gasoline allows maximum 5 % and 95E10 maximum 10 % of ethanol in terms of volume. E85 blend contains maximum 85 % ethanol, but it suits only flexible-fuel vehicles (FFV). Renewable diesel in turn can be used as such or as a blend in any diesel vehicle. Other biofuels include biogasoline and ethanoldiesel ED95.

The EU objective for transport is to elevate the share of renewable energy to 10 % of energy content by 2020. Finland has adopted nationally a more ambitious objective of 20 %. It should also be noted that carbon dioxide reductions achieved by biofuels produced from e.g. wood or waste are counted as double, which makes it easier to reach these goals. National legislation on distribution obligation of biofuels gives a stepwise development plan for transport biofuels in Finland until the 20 % target in 2020. The objective needs to be achieved by fuel producers, who may choose which fuel types and which blends they produce and bring to markets as long as the total quota is fulfilled. As gasoline blending has limits, the efforts in the coming years focus on increasing bio-share in diesel.

For LIPASTO unit emission factors this biofuel blending situation, which fluctuates annually and differs case by case, is difficult. The methodological solution of choice is to use calculated shares for renewable energy based on yearly targets set by law. The bio-based component (in terms of volume) is always announced in unit emission tables. Emission calculations are done using volume-based replacement of fossil fuels by biofuels (not based on energy content).

In Finland the target without double-counting is 13.5%. This contains first generation biofuels maximum 7 % and double-countable biofuels 6,5 % (7 % + 6,5 % = 13,5 %). When double counting is exercised, this amounts to 20 % (7 % + 2 * 6,5 % = 20 %).

Electric and hybrid vehicles

Electric vehicles can be divided into two groups:

Battery electric vehicles (BEV) that have only an electric engine and a battery that is charged with electricity from an external source. BEVs are emission free in the operational phase (driving).

Plug-in hybrid electric vehicles (PHEV) that have both electric and combustion engine. These vehicles can drive using conventional fuels (either gasoline or diesel) and/or using electricity. They also have a battery that can be charged with electricity from an external source.

Vehicles that cannot be charged with electricity but have an electric engine and combustion engine are called mild or full hybrids. This technology reduces fuel consumption, but all power nevertheless comes from the fuel. These vehicles are not considered electric cars. Emissions for these cars can be estimated to be same as emissions from a corresponding conventional vehicle with a reduction of 20 %.

Vehicle manufacturers report CO2 emissions of PHEVs according to standard driving cycle. In practice the emissions depend on how the vehicle is being used, i.e. share of driving on fuels and on electricity. We recommend emissions calculations based on estimated shares of driving using each engine. For the share of electric driving emission factors for BEVs can be used. For other driving emission factors of corresponding conventional vehicle with a reduction of 20 % can be used.

Background data

Values used for computing unit emission factors are available in the background data table.