TTW-data for heavy duty road vehicles fueled by CNG, LNG and ED95 (including CBG and LBG) has been added in this amendment.

Vehicle categories and size classes

The following vehicle types are included:

• Articulated City bus
• City bus
• Coach (no ED95)
• Regional bus (no ED95)
• Rigid truck <7.5 tonnes
• Rigid truck 7-5.12 tonnes
• Rigid Truck > 12 tonnes
• Truck with Trailer

Size classes for trucks are based on available HBFEA 4.1 segments for alternative fuels and current EU emission legislation A Rigid truck >12 tonnes has a permissible maximum weight of 14-20 tonnes, and a Truck with Trailer has a permissible maximum weight of 34-40 tonnes. Fuel consumption needs to be adjusted accordingly or manually defined if there is a large deviation in permissible maximum weight.

Fuels

CNG/LNG is assumed to be 100% fossil and CBG/LBG 100% renewable. The emissions factor for CO₂ is valid for a fuel with 90-99% methane (e.g. Swedish vehicle gas, or European average mix). If e.g. a national gas mix with both CNG and CBG is used, fossil and biogenic CO₂ needs to be adjusted accordingly. Other pollutants will not change. ED95 is assumed to contain >90% bioethanol and remaining additives to be biobased.

Emission factors for ED95 trucks are currently missing in HBEFA. These have been derived by combining known emissions factors from ED95-busses with traffic situation data for trucks, as well as validation data.

Pollutants

Emissions factor has been added for CO, HC, CH4, NOx and PM2.5 (exhaust) for all vehicles. Emission factor for SO2 has been added for ED95 vehicles only, due to low sulfur content in CNG/LNG (no SO2 emissions). N2O emissions mainly stem from NH3 and SCR-systems in diesel fueled vehicles and are negligible for CNG, LNG and ED95-fuelled vehicles.

Traffic situations and gradients

Average, motorway, rural and urban traffic situations are chosen from HBEFA for all road types except “Inner City”. Road type “Inner City” has been defined by combining selected traffic situations so that HBEFA 4.1 emissions factors aligns with validation data.

Data sources and validation

The main source of emission factor has been HBEFA 4.1. HBEFA 4.1 contain several new fuels for trucks (e.g. CNG and LNG), but also a major revision of traffic situation and driving cycles compared to HBEFA 3.3.

Three main validation activities have been carried out.

1. i) Fuel consumption for CNG-buses has been compared with data from a Swedish public transport authority. The selection of traffic situation for road types (Inner City and Suburb) is aligned with fuel data from the public transport authority.
2. ii) emission factors from HBEFA for CO, HC, NOx, and PM has been checked and partly corrected in accordance to recommendations from an independent engine test company.

iii) Emissions factors for CO2 and fuel properties has been compared to a number of literature sources.

References

HBEFA 4.1, https://www.hbefa.net/e/index.html

Swedish Energy Agency, Heating Values for Swedish fuels (LHV ED95) https://www.energimyndigheten.se/fornybart/hallbarhetskriterier/drivmedelslagen/vaxthusgasutslapp/

Swedish Gas Association, methane content for Swedish gas fuels (LHV CNG, CBG, LBG and LNG) https://www.energigas.se/fakta-om-gas/biogas/faq-om-biogas/vad-aer-energiinnehaallet-i-naturgas-biogas-och-fordonsgas/

SS 155437:2015 Automotive fuels – Ethanol for ethanol based fuel (ED95) for modified compression ignition engines – Requirements and test methods (Density ED95)

EMEP/EEA air pollutant emission inventory guidebook 2019, Passenger cars, light commercial trucks, heavy-duty vehicles including buses and motor cycles (EF, CNG/LNG adjusted for methane content)

JRC (2013). Tank-to-wheels Report Version 4.0. Joint Research Centre (JRC) Technical Reports.

Concawe, Eucar & JRC, European Commission, Luxemburg.

(EF, CNG/LNG adjusted for methane content)

NTM data assessed by IVL Swedish Environmental Research Institute