A life-cycle assessment tool for heavy-duty vehicles

Report no.7/26: This report is the supporting document to the life-cycle assessment tool for heavy-duty vehicles (HDVs) developed by IFP Energies nouvelles and commissioned by Concawe that was published in
July 2023. It describes the simulation background behind the tool.

Transport related GHG emissions represent approximately a quarter of the European Union (EU) greenhouse gases (GHG) emissions, of which, commercial road transport represents approximately a third. Therefore reducing GHG emissions from heavy duty road vehicles is an important part of the EU's target to become carbon neutral by 2050. Several technologies can contribute to heavy duty transport decarbonisation: Battery Electric Vehicles (BEVs, or their derivative, Catenary Electric Vehicles (CEVs)), Internal Combustion Engines Vehicles (ICEVs) running on low-carbon fuels (renewable diesel, renewable gas, low carbon hydrogen), Hybrid Electric Vehicles (HEVs), Plug-in Hybrid Electric Vehicles (PHEVs)) and Fuel Cell Electric Vehicles (FCEVs). Understanding the benefits and drawbacks of each solution from a life-cycle perspective for a given use case is difficult. The LCA tool described in this report aims at improving this understanding and assist in decision making.

HDVs have numerous vehicles categories, use cases and have access to many powertrains and energy carriers combinations. The tool allows to combine the following parameters to define specific use cases:

• 7 Powertrains and their efficiencies: ICEV (fuelled by diesel or diesel-like fuels, gas (compressed (CNG) or liquefied (LNG)) or hydrogen), HEV, PHEV, FCEV and BEV (and CEV);
• 5 Vehicle categories: Long-haul truck (Class5), delivery truck (Class2), city bus, coach, and refuse truck (for garbage collection);
• 5 categories of energy carriers: Diesel (fossil-based and derivatives such as B7, B30, B7+25%HVO), Diesel-like fuels with renewable characteristics (including HVO, B100 (100%
FAME), e-Diesel, biomass-to-liquid, etc.), hydrogen (grey, blue or green), CNG and LNG (fossil based, bio-based, e-fuel based), and Electricity (with variation on carbon intensity);
• Sensitivities around battery, fuel cell capacity and hydrogen tank production emissions;
• Number of battery packs used in the lifetime of the vehicle;
• Use cases (payload, trip profile, charging frequency)

Vehicle simulations were developed using Simcenter Amesim™ sketches. First, the simulations were calibrated using the “VECTO” tool (simulator for HDVs developed by the European Commission) on the “mainstream” ICEV configurations: this showed a good fit, with a less than 2% difference on fuel consumption on typical driving cycles. Then, the simulations were expanded to alternative powertrains (HEV, PHEV, FCEV, BEV). The vehicles configurations (powertrain characteristics, weight, efficiencies, battery capacity, etc.) and their conditions of use (driving cycles, payload) were selected based on a literature review of existing vehicles. The simulations results (energy consumptions) were cross-checked with data found in the literature and showed a fairly good consistency considering that the driving cycles used in the literature may vary and are not always described. Eventually, the vehicles simulations provide an energy consumption (expressed in L/100km, kg/100km or kWh/100km) for each vehicle configuration featuring the combined parameters mentioned above.

This energy consumption is converted in CO2eq emissions using the emission factors (tank-to wheel, well-to-tank and recycled CO2 contributions) of the different energy carriers (liquids, gases and electricity). On top of that are added the exhaust non-CO2 emissions (CH4 and N2O contributions, that are powerful GHGs, even when emitted in small quantities) and the emissions of manufacturing the vehicle (powertrain, chassis, battery, tank, tires), giving the life-cycle emissions of the vehicles expressed in gCO2eq/t.km (where “t” are the tons of goods transported).

An extensive use of this LCA tool for HDVs shows that the optimal options for decarbonization are highly dependent on the use case considered.