Life Cycle Assessment of a vehicle

Life cycle assessment is a methodology that accounts for emissions during the life cycle of a product or service. It estimates the impacts on several impact categories, such as climate change and air quality, from the extraction of the vehicle materials to its end-of-life. It allows a technology-neutral comparison of the different vehicles.

Figure 1: Overview of the life cycle phases for a Vehicle Source: Messagie et al. (2014)

The figure illustrates the different processes assessed for the vehicle’s life cycle. It considers both the production of the fuel and the production of the vehicle’s components, the use phase and the end-of-life management. For each process, the impacts on every category are aligned with the scope of the study. The indicators and their definition can be found here. 

To carry out the analysis, the Life Cycle Assessment methodology is divided into the following phases:

In the context of decarbonising the vehicle fleet, the LCA allows the comparison of vehicles’ technology in an objective and technology-neutral way. The figure below shows results obtained for the LCA of a passenger car with different fuel use. The impact category assessed is climate change. It is characterised by all the emissions from greenhouse gas (GHG) due to both biological and, mainly, anthropogenic processes. The emissions from different GHG are aggregated into one unit CO2 equivalent. It means that the intensity of emissions of each substance is weighted based on the impacts relative to CO2. The values are multiplied by a characterisation factor called Global Warming Potential defined by the IPCC.

Figure 2: Impact on climate change of the LCA of passenger cars for different fuel use Source: De Clerck et al. (2020)

Figure 2 shows the impact on climate change of different vehicle powertrains. Excluding electric vehicles and fuel cell electric vehicles (FCEV), most emissions originate in the tank-to-wheel stages. Thus, electric vehicles are the less polluting vehicle in general. For FCEV, while there are no tailpipe emissions, the impact of the car depends mainly on the production processes of hydrogen, which is very carbon-intensive. Green hydrogen produced through electrolysis based on a low-carbon  electricity mix could offer a solution to reduce the impact of the well-to-tank processes for such cars’ development in the future. 

The potential of electric vehicles to decarbonise the transport sector could increase with the goal also to decarbonise electricity production. Indeed, EV impacts depend on the electricity mix of countries. This mix can greatly affect the overall effects on climate change. Figure 3 shows the impacts of electric vehicles compared to diesel vehicles for different electricity production sources in Europe.

Figure 3: Impact on climate change of  the LCA of electric passenger cars depending on the electricity production sources Source: Messagie (2021)

It shows that the bigger impacts reduction are obtained for countries where the electricity mixes rely on less polluting production processes (renewables or nuclear power). Thus, decarbonating the electricity production will also make electric vehicles an even more promising alternative for cleaner mobility and transport in terms of climate change potential. 

Biofuels are other alternative options with the potential to reduce the WTW impacts of ICE vehicles. However, while the CO2 uptake compensates CO2 tailpipe emissions during the feedstock growth, the emissions from the WTT phases are mainly due to the agricultural processes and the indirect land-use change impact (ILUC). Indirect land-use changes refer to the unintended emissions due to the land use change to produce biofuels (i.e., deforestation). 

Figure 4 shows the effect on climate change of different biofuels production, including ILUC for different regions of the world compared to diesel and gasoline WTW processes. This study from ICCT illustrates that biofuel can be more carbon-intensive than diesel and gasoline in some cases. For this reason, second-generation biofuels (i.e., based on wastes) could be an alternatives to avoid the ILUC impacts and the growing processes of more biological materials. 

Figure 4: Impacts of the more relevant biofuel production pathway for Europe, the US, China and India compared to the production and combustion of gasoline and diesel Sources: Bieker (2021)

References and useful link:

LCA Framework: Life cycle assessment

Messagie M, Boureima F-S, Coosemans T, Macharis C, Mierlo JV. (2014) A Range-Based Vehicle Life Cycle Assessment Incorporating Variability in the Environmental Assessment of Different Vehicle Technologies and Fuels. Energies, 7(3),1467-1482. https://doi.org/10.3390/en7031467

De Clerk, Q., Hooftman, N., Mommens, K., Nuyttens, J., & Vanhaverbeke, L. (2020). Etude d’impact sur la mobilité, sur les aspects économiques et sociaux et sur l’énergie et roadmap vers une sortie des véhicules thermiques – Rapport final du volet 1, Partie 1 : Evolutions technologiques, étude d’impact sur l’environnement et l’énergie – STRATEC Bruxelles Environnement 

Messagie M. (2021). Life Cycle Analysis of the Climate Impact of Electric Vehicles – Transport & Environment

Bieker, G. (2021). A GLOBAL COMPARISON OF THE LIFE-CYCLE GREENHOUSE GAS EMISSIONS OF COMBUSTION ENGINE AND ELECTRIC PASSENGER CARS. www.theicct.orgcommunications@theicct.org

The ecoscore methodology is based on a well-to-wheel approach that is explained here. For the LCA approach, this phase is included and is extended to all the phases from the life cycle. It means that the production of the vehicle, but also its end-of-life, is included. Besides, while climate change, air quality and noise pollution are the parameters assessed in the Ecoscore methodology, the LCA method includes extended assessments over more indicators such as land use or resource depletion. 

Given the context of the materials’ extraction with batteries and EV development, social LCA (S-LCA) is becoming more important. Its methodological methodology framework is similar to LCA. However, it focuses on estimating and quantifying social risks within the life cycle. Indicators for S-LCA include child labour or injuries in the workplace.