The study concerns the life cycle assessment (LCA) of a prototype electric racing car, Formula Student, developed by students of the Poznan University of Technology under the name of eVarta. The main objective of this study is to identify critical environmental points and indicate key elements of the vehicle's life cycle, along with the impact of the assumptions made. In the first part of the work, a literature review and standard review are conducted to organise the information and methodological steps for the LCA components and their application in the subsequent stages of the study. The work focusses on defining the right assumptions, the process of data collection and its appropriate aggregation, as well as the creation of a functional structure for the object under study. SimaPRO software is used to perform the assessment. The results of the evaluation show the high importance of the vehicle transportation stage in the entire life cycle and the significant impact of the transport-related processes, mostly considering the fact that the eVarta is a concept racing car, used only in specific conditions of Formula Student races around the world. Most of the distances between races are covered using external transport means, and eVarta is used only for racing. The second main source of environmental impacts is related to the use of resources associated with the production of the high-voltage traction battery and the use of aluminium and related processes. eVarta is a custom concept race car, designed and built by the team of students from different faculties at Poznan University of Technology (Poland). As a prototype, eVarta demonstrates high levels of environmental burden related to the production of materials and techniques. The proportion of these impacts may be limited by using a 3D CAD model to improve the information flows regarding the production of all parts. Moreover, the reduction of the environmental impacts may be reached by: (a) enhancement of production of traction battery, (b) substitution of construction materials, and (c) improvements during use, e.g. implementation of energy recovery systems during braking.
B. Ros, J. Selech and J. Kasprzak have contributed equally to this work.
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Introduction
Life cycle assessment (LCA) research in the field of battery electric vehicles (BEVs) exhibits a range of focusses and depths (Bossche et al. 2006; Matheys et al. 2008). Some studies focus exclusively on specific BEV components such as the traction battery and power electronics, often relying on confidential life cycle inventories (Daimler 2010; Majeau-Bettez et al. 2011; Ellingsen et al. 2014).
On the contrary, other research adopts a more holistic approach, examining the environmental impact of both electric and hybrid vehicles by considering the entire vehicle. This broader perspective is evident in other studies (Ellingsen et al. 2014; Frischknecht and Flury 2011; Faria et al. 2012; Bartolozzi et al. 2013). These works typically utilise aggregated data from public sources and investigate the production aspects of BEV powertrains and batteries with varying degrees of detail and transparency. Some of these studies also focus on specific stages of the vehicle life cycle, such as use or production (Donateo et al. 2013; Nanaki and Koroneos 2013; Girardi et al. 2015; Casals et al. 2016).
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The most comprehensive and detailed environmental comparisons between conventional and electric vehicles are found in the studies, which assess the full life cycle of vehicles, including high-voltage batteries and other components, using well-detailed inventories (Pero et al. 2018a; Notter et al. 2010; Bauer et al. 2015; Lombardi et al. 2017; Tagliaferri et al. 2016; Naranjo et al. 2021; Silvestri et al. 2019). These articles evaluate the entire life cycle of the vehicle, including both the high-voltage battery and other car components, and stand out for their use of detailed inventories and model parameters to assess various environmental impacts. These studies have shown that electric vehicles (EVs) can provide climate benefits, although the results depend considerably on several elements such as battery size or the CO2 content of the electricity (Bauer et al. 2015; Naranjo et al. 2021), battery effective production and disposal (63). Other studies presented a well-to-wheel assessment of CO2 emissions and costs for current light-duty vehicles (Elgowainy et al. 2016; Bieker 2021; Szumska et al. 2022; Alanazi 2023). They found that plug-in hybrid electric vehicles (PHEVs) offer attractive carbon emissions abatement costs under certain conditions. Some studies emphasises that only battery electric vehicles (BEVs) and hydrogen fuel cell electric vehicles (FCEVs) have the capability to achieve significant reductions in life-cycle greenhouse gas (GHG) emissions, which is essential for meeting the objectives of the Paris Agreement.
Currently, registered BEVs in regions such as Europe, the United States, China, and India already exhibit lower life cycle GHG emissions compared to similar gasoline cars—approximately 66–69% in Europe, 60–68% in the United States, 37–45% in China, and 19–34% in India (Bieker 2021). By 2030, as the energy mix becomes more decarbonised, this emissions gap is projected to increase further, although the BEVs registered today already demonstrate a substantial decrease in average GHG emissions over the life cycle.
Due to their advantages and the urgent need to address climate change and energy stability, various countries are actively supporting electric vehicles (EVs). In the United States, the number of plug-in electric vehicles (PEVs) on the road has increased significantly since 2011, with more than 275,000 PEVs in use. Since their market introduction in 2010, EV sales in Europe have seen a fourfold increase annually, reaching more than 2 million sales by September 2021. China, which is rapidly moving towards the adoption of electric vehicles, aims to make electric vehicles comprise 20% of total new car sales by 2025 and targets all new cars sold as new energy vehicles (NEV), including electric and plug-in hybrids, by 2035.
However, despite these efforts and the numerous benefits of electric vehicles, they still represent a small fraction of global car sales, accounting for only 14% of all passenger cars. One major hurdle for the widespread adoption of electric vehicles is the current state of battery technology, which presents challenges such as limited range, long charging times, and high initial costs (Alanazi 2023; Burzyński 2022). Additionally, the scarcity of charging infrastructure poses another significant barrier. This creates a "chicken-and-egg" dilemma: drivers are hesitant to switch to EVs without extensive charging networks, yet the lack of EVs on the road discourages substantial investment in charging infrastructure development.
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Over time, as environmental awareness has grown, numerous sustainable transportation strategies have been adopted worldwide. These include the exploration of alternative fuels, the enhancement of public transportation, the introduction of innovative design concepts, and the development of alternative powertrains, notably electric vehicles (EVs). Although electric vehicles promise reduced tailpipe GHG emissions, they come with their own set of challenges. For example, battery production can account for up to 50% of a vehicle's CO2-equivalent emissions during its manufacturing. Furthermore, the environmental benefit of electric vehicles is dependent on the energy source used to power them. If electricity is derived primarily from fossil fuels, the environmental advantage diminishes.
Electric mobility is increasingly being viewed as a key solution to reduce carbon emissions in the transport sector, leading to a surge in scientific papers evaluating the environmental impacts of electric vehicles (EVs). However, the growing body of the literature also presents conflicting findings. Some reviews, such as that of Hawkins et al. (Hawkins et al. 2012), point to the absence of a comprehensive and transparent life cycle inventory (LCI) as a major gap in life cycle assessment (LCA) studies.
However, electric vehicles (EVs) have now emerged as the leading alternative, which includes various technologies such as hybrid electric vehicles (HEV), fuel cell electric vehicles (FCEV), and plug-in hybrid electric vehicles (PHEVs) (Fajardo et al. 2018). EVs have several advantages over traditional internal combustion engines, including zero emissions, reduced maintenance, and greater efficiency (Hawkins et al. 2013). Using electricity instead of fossil fuels can significantly reduce greenhouse gas emissions, with potential savings of 90% for electric vehicles, 25% for hydrogen vehicles and 50–80% for PHEVs (Tagliaferri et al. 2016). However, the selection of energy storage devices for electric vehicles depends on multiple factors, including energy density and life cycles (Abumeteir and Vural 2016). Although electric vehicles are rapidly gaining market share, there remain challenges, especially with regard to environmental impacts during their manufacturing, use, and disposal.
This is because the global economy and social advances have accelerated urbanisation, leading to a surge in automobile demand (Nimesh et al. 2021). Traditional vehicles are mainly based on fossil fuels, leading to environmental concerns such as climate change, air pollution, and energy scarcity (Marmiroli et al. 2020). Consequently, many regions are moving to electric vehicles (EVs) as a sustainable alternative (Verma et al. 2022). The global market for power batteries is also expected to grow, reaching 3555 GWh by 2030.
Understanding the environmental implications of electric vehicles, especially their batteries, is crucial for their sustainable integration (Sharma et al. 2013; Duce et al. 2016). There is a debate about the eco-friendliness of electric vehicles. Their production has higher environmental impacts than traditional vehicles, but the impact of their operational stage varies depending on the power source (Pero et al. 2018b; Qiao et al. 2017). The disposal could offset some production impacts, but concerns remain, especially with respect to tyre and brake wear particulate emissions (Samaras and Meisterling 2008; Sisani et al. 2022). A comprehensive life cycle assessment (LCA) can provide information on the environmental viability of electric vehicles compared to traditional vehicles (Andersson and Börjesson 2021; Tagliaferri et al. 2016).
Motorsport, especially Formula-E racing, offers a platform for driving technological advances in electric vehicles. Historically, motorsport has been a catalyst for innovation, promoting the development of high performance, efficient and lightweight solutions (Institution of Mechanical Engineers. History of Formula Student(2023).https:, , www.imeche.org, events, formula-student, about-formula-student, history-of-formula-student.Accessed 03 Mar 2023. 2023; Ros 2023). As the Formula E championship evolves, there is an opportunity to optimise motor designs for maximum performance while minimising the use of critical materials (Ros 2023).
In this study, life cycle assessment (LCA) studies have been conducted to assess the environmental impact of electric vehicles, the Formula Student Car, especially focussing on their design options (Ros 2023; EPSA Team. Formula Student Competitions 2023). This knowledge will enable the Race Up Team to make informed decisions about material selection for future car models, potentially opting for alternative materials for the most impactful components to enhance environmental performance. The primary objective of this dissertation is to implement the life cycle assessment (LCA) technique, according to ISO standards, on a single seat racing vehicle constructed by a group of engineering students. The focus is on analysing the environmental effects of each individual system within the vehicle. Although evaluating the overall environmental footprint of the vehicle would be beneficial, the absence of comparative LCA data on similar category race cars precludes a broader comparative analysis (Verma et al. 2022). Therefore, the investigation will not take into account the general environmental implications of the vehicle. Comparative LCAs would be valuable if there were existing studies on comparable vehicles; however, the application of an LCA to a Race Up Team vehicle is an innovative approach, leaving no benchmark for comparison with other vehicles. Consequently, environmental impact comparisons will be internal and examine different components within the same vehicle rather than between multiple vehicles. Although some studies have focused on complete vehicles or their traction batteries, others have examined specific stages of the life cycle. However, there is a research gap on traction motors for electric vehicles, particularly with respect to material wastage during production (Hirz and Brunner 2015). These motors often incorporate elements of rare earth that have environmental, economic, and strategic implications.
Section "Methods" introduces LCA, a method for quantifying environmental impacts. Sections "Results" and "Discussion and Interpretation of results" discuss the environmental impacts of electric vehicles and their batteries, respectively. Conclusions and recommendations are drawn in Section "Conclusions".
Methods
Vehicle lifecycles are influenced by a number of elements, such as technical attributes, energy sourcing and provision, operational duration, and the techniques employed in both production and recycling (Ros 2023). A crucial component in technical attributes is the propulsion mechanism, a factor that buyers frequently scrutinise to ensure a harmonious balance between resource and energy expenditure. Traditional propulsion mechanisms employ internal combustion engines that predominantly consume fossil fuels during their operational duration. In contrast, for electric vehicles (EVs), most of the resources are expended during the production stage, particularly in the fabrication of batteries, storage mechanisms, and drivetrains. Thus, the provision of resources and energy is the secondary factor, the third shaped by the techniques used in production and the recycling approach at the end of the product’s life. Operational duration encompasses lifecycle-associated factors including transportation needs, individual driving habits, and the energy and resources (like fuel and electricity) used to maintain equilibrium (Ros 2023).
Life cycle assessment (LCA)—methodological remarks
The International Organisation for Standards (ISO) recognises ISO 14040 and ISO 14044 standards as benchmarks for executing LCA (ISO 14040:2006. 2006; ISO 14044:2006. 2006). This method offers a quantitative evaluation of a product or system's environmental footprint throughout its existence, from raw material extraction to its eventual recycling or disposal.
LCA typically comprises four primary phases: (1) determining goals and scope, (2) inventory analysis, (3) life cycle impact assessment, and (4) interpretations.
Determining goals and scope
This phase ensures that the LCA is tailored to a specific functional unit within set system boundaries and a defined analysis time frame. The boundaries of the system can range from expansive to limited, depending on the product or service under scrutiny (Finnveden et al. 2009). Given the intricate nature of modern supply chains, expansive boundaries aid in pinpointing processes with significant environmental implications. The system boundary delineates which processes are included in the LCA, based on initial assumptions, intended use, and exclusion criteria. The functional unit provides a reference point, facilitating the comparison of fundamentally different systems (Rebitzer et al. 2004). The duration of the analysis can significantly influence LCA outcomes, especially as energy consumption during processes evolves over time. The reliability of LCA results is also dependent on the quality of the data used.
Inventory analysis
This phase examines the amount of energy and materials consumed or produced at each supply chain node. It encompasses three primary steps: creating a flow diagram, collecting data on material inputs, products, by-products, solid waste, and emissions, and calculating each in relation to the functional unit (Babu 2006).
Life cycle impact assessment
This phase calculates the cumulative environmental impact after the inventory analysis. Environmental impacts include freshwater, marine, and terrestrial eutrophication, human toxicity levels, ozone depletion, land alteration, and climate change (Hauschild 2017; Messagie et al. 2010; Lee and Inaba 2004). For each impact factor, category indicators are chosen. There are several life cycle impact assessment methods, such as the Tool for Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI) and ReCiPe (Sleeswijk et al. 2008; Huijbregts et al. 2016; Bare et al. 2003; Murray 2003; Bare 2011, 2012).
In the LCIA step, the mandatory activities listed in the ISO standard are carried out to assess the impact of elementary flows obtained in the inventory analysis phase, which are basically the amounts of emissions or substances calculated from the inventory (Bare et al. 2003; Murray 2003; Bare 2011; European Environment Agency 1997). The software used for the subsequent LCA phases was SimaPRO version 9.4.0.2. Impact categories are assigned according to the selected impact assessment method.
The representation of the characterisation results includes a total of 18 different impact categories, named midpoint impact categories. For the purpose of legible graphical representation, acronyms have been used, which, along with the associated unit of equivalence, are presented in Table 1, in order of appearance in the graphs of the characterisation results.
Table 1
The description of midpoint impact categories in the ReCiPe 2016 method (Huijbregts et al. 2016)
Acronym
Impact category
Impact indicator unit
Gl. warming
Global Warming
kg CO2 eq
Str. ozone depl
Stratospheric Ozone Depletion
kg CFC11 eq
ionising rad
Ionising Radiation
kBq Co-60 eq
Ozone form. HH
Ozone Formation, Human Health
kg NOx eq
Fine PM form
Fine Particulate Matter Formation
kg PM2.5 eq
Ozone form. ES
Ozone Formation, Terrestrial Ecosystems
kg NOx eq
Terr. acid
Terrestrial Acidification
kg SO2 eq
Freshwater eutro
Freshwater Eutrophication
kg P eq
Marine eutro
Marine eutrophication
kg N eq
Terr. ecotox
Terrestrial Ecotoxicity
kg 1,4-DCB
Freshwater ecotox
Freshwater Ecotoxicity
kg 1,4-DCB
Marine ecotox
Marine ecotoxicity
kg 1,4-DCB
Human CT
Human carcinogenic toxicity
kg 1,4-DCB
Human NCT
Human non-carcinogenic toxicity
kg 1,4-DCB
Land Use
Land Use
m2a crop eq
mineral res. scarcity
Mineral Resource Scarcity
kg Cu eq
Fossil res. scarcity
Fossil resource scarcity
kg oil eq
Water consumption
Water Consumption
m3
Drawing interpretations
This final phase of the LCA offers a systematic approach to interpret the results of the evaluation. It summarises and evaluates the results based on the LCA analysis, with the aim of ensuring the confidence level in the final results and communicating them transparently (Hauschild 2017).
eVarta case study
Objective of the study
The goal of the study is to assess the environmental impact of the prototype Formula Student race car, which is composed of 5 different subsystems (functional groups of components). This LCA is supposed to help identify environmental hotspots and facilitate further design decisions considering environmental criteria, so the results obtained should be used internally.
This study focusses on the comparison of all subsystems of the car, divided according to the criteria of their purpose. The presented results will allow one to highlight the most impactful areas of the prototype car, and they are mostly directed to members of the Poznan University of Technology–Motorsport Team (and possibly other teams contributing in similar competitions), in order to introduce information on the environmental burdens of each individual group of components to be used in the next constructions.
Scope and functional unit
As mentioned, eVarta is a unique vehicle, designed and manufactured for a specific purpose, participation in races of similar cars created by student science clubs from various countries and universities. The use phase is particularly specific, because the car is built for only one racing season (about 12 months). After this time, in accordance with competition regulations, the prototype cannot be reused in an unchanged form, and creating subsequent iterations of the vehicle is the primary goal of development in the student team. No form of final disposal takes place; after a year, the expired prototype is kept as a kind of showpiece/exhibit. The considered system boundaries are defined in Fig. 1.
Fig. 1
eVarta case study system boundaries
×
Based on PUTM internal data, the estimated distance that the vehicle will cover in total over its full life cycle is 2,000km. (The value was averaged based on historical data, participation in international competitions, and test sessions.) Based on the assumed distance, one full cycle of competition (equivalent to 2,000km driven in various activities) was defined as the functional unit.
Data assumptions and limitations
According to the methodological approach described in Nordelöf et al. (2014), the presented study is carried out as an analysis of the “life cycle of equipment” (according to the terminology used in ISO 14040:(2006). (2006)), with a limitation on the final disposal of the vehicle.
Creating the vehicle model required setting certain assumptions, without which virtualisation of the research object would not have been possible. The assumptions apply to all stages of the vehicle's life cycle and have been adapted to the available data, geographic position, or technology used. The most important assumptions made include the following:
(1)
The manufacturing data or records required for processes’ energy consumption are based on the Cost and Manufacturing document, which is an official documentation prepared by the PUT Motorsport team for the competitions’ judges.
(2)
All of the measurements have been taken directly from the 3D CAD model, which represents the object with nearly 95% accuracy.
(3)
The transportation data have been calculated based on historical data of PUTM participation in international competition, using the geography of Poland.
(4)
In the model structure, there are three groups of components: in-house, outsourced, and bought. Within the Bought components, the manufacturing data were insufficient, so they are modelled as the mass input of the raw material. For outsourced components, the generic data have been used due to high differentiation of part suppliers. Data quality information is presented in Tab. II; the raw data for LCI are presented in Tab. III in Supplementary Information.
(5)
The use stage includes the energy use of the car, as well as the additional (spare) parts. The energy use corresponds to 2,000km driven in various activities; the Polish energy mix (Low-Voltage Electricity PL) and energy mixes appropriate for the countries where the race sessions took place were used; the list of spare parts is presented in Tab. IV in Supplementary Information; and data for energy use and transport-related processes are presented in Tab. V in Supplementary Information.
(6)
Specific assumptions have been defined for transport-related processes, because eVarta is a vehicle for a specific purpose, dedicated to track racing. As such a vehicle, eVarta does not travel independently to racing destinations, but its relocation is accomplished by other means of transport. In each case, a diesel powered light commercial vehicle (LCV) with a payload of up to 3.5 t, characterised by emission levels in accordance with the EURO6 standard, was used.
(7)
Due to specific assumptions related to the end-of-life part of eVarta (as reported in Section "Scope and functional unit"), this stage has been omitted.
(8)
The source data sets for modelling the research object have been taken from ecoinvent v3.8 databases.
Data structure and vehicle model
To facilitate the exploration of resources, the vehicle assembly has been divided into five basic structural groups containing main components, while in the lower layer, there are individual parts, including fasteners (standardised elements). The main structure of an assembly, which was applicable during the entire data collection and modelling into the LCA software, is presented in Table 2.
Table 2
The structure of the assembly of the CAD model with weight distribution
No
Part group
Description
Unit mass [kg]
Mass share [%]
Quantity
1
PUTM-F-Assembly
Frame/chassis assembly
68
30
1
2
PUTM-A-Assembly
Aerodynamics components
7
3
1
3
PUTM-G-Assembly
Electronic modules and harnesses
12
5
1
4
PUTM-H-Assembly
High-voltage components
85
38
1
5
PUTM-S-Assembly
Suspension components
56
24
1
Vehicle mass
229
As shown in Table 2, the overall weight of the vehicle is 229 kg, in comparison with the stated 235 kg in a ready-to-drive state, which gives approximately 2.5% of divergence (Tab. I in Supplementary Information). The percentage mass share between components of each functional assembly is also presented in Table 2.
Due to the specifics of the research object as its unit production of a vehicle according to specific assumptions (regulations), all data on production processes and materials used are from the technical documentation of the PUT Motorsport team. Additional information that was necessary for the data collection has been taken from the Cost and manufacturing report document.
The first form of documentation to create a BOM of individual vehicle systems was 3D documentation. Due to technical and design requirements, a great emphasis was placed on creating a 3D model with very high accuracy, due to mass accuracy criteria. The overview of the eVarta CAD model is shown in Fig. 2.
Fig. 2
The complete CAD assembly of eVarta
×
The chassis assembly consists of high-strength steel tubes that are joined using TIG welding technology. In addition to the tubes, which are structural elements, brackets and auxiliary elements made of flat steel sheets are additionally connected. The geometry of these elements is obtained using laser cutting technology. Second, there is an impact energy absorber at the front, which consists of a steel plate together with a composite actuator. The frame structure, including the supports, was powder coated for protection. The overview of chassis components is presented in Fig. 3.
Fig. 3
The chassis assembly of eVarta
×
The suspension system assembly, shown in Fig. 4, is the most extensive in terms of the number of components in the model being prepared. The vast majority of the components are made of high-strength aluminium alloy, while the processes involved in chip machining (CNC) dominate within this group of parts.
Fig. 4
The suspension assembly of eVarta
×
Parts classified in the electronics group are related to the operation of low-voltage systems. The main component here is the low voltage battery, which consists of cells that are identical to the traction battery, but with fewer cells and configurations. In addition to the battery, there are also electrical harness components or telemetry modules, responsible for the acquisition of data collected during driving. The overview of this system is illustrated in Fig. 5.
Fig. 5
Electronics assembly of eVarta
×
The parts included in aerodynamics represent, in terms of weight, the smallest percentage of the entire car assembly. Hand-lay-up laminated composites mainly make up this assembly. There are also aluminium-alloy machined brackets and laser cut elements included. The graphical representation of aerodynamics components is shown in Fig. 6.
Fig. 6
Aerodynamics assembly of eVarta
×
The last group resulting from the adopted structure is the high voltage (HV) assembly, whose 3D graphical representation is shown in Fig. 7.
Fig. 7
High-voltage assembly of eVarta
×
The components included in the HV group represent the most complex structure, especially due to the traction battery layout and other multi-material components, such as cooling system, electric switches, and power cables.
Results
The results of the characterisation of the eVarta lifecycle are presented in Fig. 8, corresponding to the designations assumed in Table 1. Values represent the percentage contribution of the different stages of the life cycle of eVarta, with respect to the total impact for each category.
Fig. 8
Results of the characterisation of the eVarta life cycle
×
The manufacturing stage consists of all the resources and processes required for the ready-to-drive state of the vehicle. The use stage is related to the use of electrical energy for battery charging (635 kWh for lifespan), transport (approximation of 1500 tkm), spare parts (additional tyre sets, rims, and replacement parts required for vehicle operation) and the battery charger unit. Following the established assumption, the final disposal has been omitted due to the specificity of the project and its prototype nature.
Manufacturing leads significantly over the other stages in the categories of mineral resource scarcity, human cancerogenic and noncancerogenic toxicity, terrestrial, freshwater and marine ecotoxicity, and marine eutrophication. It is possible to recognise a deviation from this trend where the transportation stage has a dominant or closely similar influence compared to the production. This includes the categories of impact on global warming, stratospheric ozone depletion, ozone formation (both human health and terrestrial ecosystems), land use, and fossil resource scarcity.
The other elements of the vehicle life cycle, in general, present a much lower impact compared to the production and transportation stages. Taking these elements into account, the largest deviation is seen for the water consumption category: electricity (use stage) has a strong influence within this category.
The characterisation results of the eVarta manufacturing stage are presented exclusively in Fig. 9. The values represent the percentage contribution of the eVarta subassemblies, with respect to the total impact for each category.
Fig. 9
Environmental impact of subassemblies of the eVarta race car—characterised results for 18 impact categories (ReCiPe 2016)
×
The contribution of each subassembly varies with respect to the subsequent impact categories, and the dominant contribution of components from the suspension group is clearly seen in the categories of global warming, PM formation, ozone formation, as well as human carcinogens and fossil resource scarcity. The second group, considering the percentage contribution is the high voltage assembly, leads to high impact for terrestrial ecotoxicity, freshwater ecotoxicity, or marine ecotoxicity—in that case, after analysing the process contribution tree, the use of copper-based materials within the HV and electronics group is casing the significant impact compared to the suspension group. In Tab. VI in Supplementary Information, the characterisation results (equivalent values) for the entire vehicle are listed.
Among all the impact categories selected, the four categories that appear most frequently in publications on vehicle environmental assessment and are closest to current issues in the automotive industry were selected. The following graphs correspond to:
Global warming,
Ozone formation—human health,
Mineral resources scarcity,
Scarcity of fossil resources.
Furthermore, the results representation for each group of vehicle components is provided with mass data to better determine the importance of the mass input of the components with respect to its environmental score. This format of result representation facilitates the overview of impacts corresponding for selected impact categories and enables direct comparison between the construction (component) groups or lower-layer parts. “Group mass” refers to the total mass of each subassembly, while “Group score” refers to the total amount of environmental impact related to the subassembly.
In the characterisation results for the global warming category, it is noticeable that by far the largest share of impact is visible for components in the suspension group. The second largest score is achieved by the HV components, with nearly 50% less CO2 equivalent score than the leading Suspension assembly. Although the overall mass of the chassis group is relatively large, it does not affect the result that much. The complete representation is shown in Fig. 10.
Fig. 10
Comparison of the results of the global warming category in eVarta
×
For the category of ozone formation, the overall distribution is very similar to the representation of global warming, with suspension components leading the HV group by nearly 30%. The complete representation is shown in Fig. 11.
Fig. 11
Comparison of the results of the category of ozone formation in eVarta
×
Within the mineral resource scarcity category, as presented in Fig. 12, the leading group is the HV components with Suspension in second place. The most visible change in trend is in the field of electronics, with a much higher score that is relevant to the mass value.
Fig. 12
Comparison of the results of the mineral resources scarcity category in eVarta
×
The category of fossil resource scarcity is shown in Fig. 13. The leading group is the suspension assembly with the HV components following.
Fig. 13
Comparison of fossil resource scarcity category results in eVarta
×
The following four graphs represent the characterisation results (four selected impact categories) for the parts that make the greatest contribution to the results within each group of components. The exact representation is shown in Figs. 14, 15, 16, 17.
Fig. 14
Comparison of the scores of the category of global warming—the parts most contributed
Fig. 15
Comparison of scores of the ozone formation category—the most contributed part
Fig. 16
Comparison of mineral resource scarcity scores: the most contributed parts
Fig. 17
Comparison of fossil resources scarcity category scores: the most contributed parts
×
×
×
×
In the categories of fossil resource scarcity, ozone formation, and global warming, the leading part is the Rim (made of magnesium alloy). The second impactful component within the categories analysed is the battery pack (containing lithium cells). In all cases, the impact of undertray and main frame is relatively low, as represented in the aggregate data for each construction group (Figs. 10, 11, 12, 13).
Having analysed the characterisation results for the entire vehicle, the next step is to review the relative contribution for individual subsystems. For the suspension system, consisting of the largest number of modelled components, resulting from the adopted structure, the characterisation results are shown in Fig. 18. For the impact categories of global warming, fine PM formation, and fossil resource scarcity, the leading impactful component is the Rims set. In categories such as terrestrial acidification, eutrophication, and mineral resource scarcity, the front uprights have the greatest impact. This is dictated by the complex machining, the use of aluminium, and the high waste factor.
Fig. 18
Environmental impact of suspension of the eVarta race car—characterised results, ReCiPe 2016
×
Components such as engine mounts and rear uprights maintain a similar distribution in the subsequent impact categories due to their nearly identical technological process and material, but differ in mass contribution. The greatest variation is observed in the category of impacts on terrestrial ecotoxicity. In the graph, the values for the tyre set present a particular spike, which, having analysed the contribution of the process, is caused by the bead wire; the main process that causes the high environmental score is the acquisition of ferronickel.
Another group of components under review is the chassis assembly, whose results are presented in Fig. 19. By a wide margin, the highest score in all impact categories is the main frame, consisting of steel tubes and contributing welding processes; the high impact is caused by the largest mass share in the entire subassembly.
Fig. 19
Environmental impact of the chassis of the race car eVarta—characterised results, ReCiPe 2016
×
Noticeable differences in the trend are visible in the stratospheric ozone depletion impact category. For components such as the driver seat and exterior panels, the raw materials involved in the manufacturing of composite plastics have a significantly greater impact, compared to steel and its associated processes. The pedalbox assembly shows a noticeable impact across most categories, caused by the aluminium processing and machining. Similarly, the impact actuator appears as the third most impactful component, with a considerable contribution of steel and laminated composite processing.
Among the components of the high voltage group, the characterisation results of which are presented in Fig. 20, the significantly greatest impact of the battery packet for freshwater ecotoxicity, terrestrial ecotoxicity, human carcinogens, and scarcity of mineral resources can be observed.
Fig. 20
Environmental impact of high voltage of the race car eVarta—characterised results, ReCiPe 2016
×
An important impact on global warming, ionising radiation, and fossil resource scarcity flows from the battery box, which is the second largest in terms of percentage contribution to the considered impact categories. Fasteners or cooling systems have the smallest percentage contribution in all categories analysed. The impact on marine eutrophication shows the greatest variation between components, with a significant peak in values for the engine. When the process contribution is analysed, this distribution may be caused by the high proportion of processes associated with rare-earth concentrates, which are used in permanent magnet production.
The electronics group, along with the aerodynamics assembly, is second last considering the mass share of the entire vehicle. Figure 21 represents the characterisation results for all components of the electronics group. The overall distribution for global warming, stratospheric ozone depletion, ionising radiation, and freshwater and marine eutrophication shows a nearly 50% impact share by the PDU system. This component individually shows the greatest impact in most categories.
Fig. 21
Environmental impact of electronic devices of the race car eVarta—characterised results, ReCiPe 2016
×
The electrical harness, similar to the former construction groups, presents a much higher relative impact on terrestrial ecotoxicity due to the high proportion of copper throughout the component unit of the power cables.
The last group discussed are the components, whose result representations are shown in Fig. 22. This subassembly is sharing only 3% of the entire vehicle mass.
Fig. 22
Environmental impact of aerodynamics of the race car eVarta—characterised results, ReCiPe 2016
×
When assessing the results, it can be noticed that the distribution presented among different impact categories is found even. The uniformity is due to the use of almost the same types of raw materials and production processes (hand lamination), with different proportional mass inputs, resulting in a similar distribution in all impact categories. With the largest mass share, the undertray elements contribute more than 50% in the categories of global warming, ionising radiation, PM formation, human cancerogenic toxicity, or mineral resource scarcity.
The greatest diversity is seen in the categories of human cancerogenic toxicity and mineral resource scarcity. When tracing the contribution of processes to these categories, the use of energy for processes related to steel production affects the results.
Discussion and interpretation of results
According to European Environment Agency (1997), during the interpretation phase, one should pay attention to several issues concerning: hotspot analysis, LCI level (data analysis), LCIA level (sensitivity in each phase of assessment), and uncertainty analysis. This study performs hotspot analysis and analysis from the LCI point of view. Sensitivity analysis is performed for one variable (LCV transport—differences in distance).
By analysing the process tree, it was possible to structure the information and allow to determine the environmental hotspots within the vehicle structure. Following the review of the characterisation results, the high-voltage and suspension groups dominate by a large percentage. For each of the impact categories examined, the traced leading process/resource use is presented in Table 3.
Table 3
The summary of the largest contribution of components for all impact categories
No
Impact category
The highest contribution
Leading component
Comment (leading process/resource use)
1
Global Warming
Suspension
Rim
high use of electrical energy, aluminium ingots
2
Stratospheric Ozone Depletion
HV
Battery packet
gold, printed electric circuits processing
3
Ionising Radiation
Suspension
Front/rear uprights
use of electricity, aluminium processing
4
Ozone Formation, Human Health
Suspension
Rim
use of electricity, aluminium processing, magnesium cast alloy;
5
Fine Particulate Matter Formation
Suspension
Rim
magnesium cast alloy processing, use of electricity
6
Ozone Formation, Terrestrial Ecosystems
Suspension
Rim
aluminium processing, magnesium cast alloy processing, high use of electricity
7
Terrestrial Acidification
HV
Battery packet
graphite for lithium batteries, copper (cathode)
8
Freshwater Eutrophication
HV
Battery packet
graphite for lithium batteries, copper (cathode)
9
Marine eutrophication
HV
Engine
Rare-Earth Concentrate Extraction, Permanent Magnet for Electric Motor Production
10
Terrestrial Ecotoxicity
HV
Battery packet
copper (cathode), graphite for lithium battery production
11
Freshwater Ecotoxicity
HV
Battery packet
Electrorefining of copper, production of copper—mine operation
12
Marine ecotoxicity
HV
Battery packet
Electrorefining of copper, production of copper—mine operation
13
Human carcinogenic toxicity
Suspension
Front/rear uprights
aluminium and processing
14
Human non-carcinogenic toxicity
HV
Battery packet
copper production, copper electrorefining
15
Land Use
HV
Battery packet
Electrorefining of Copper
16
Mineral Resource Scarcity
HV
Battery packet
Electrorefining of Copper
17
Fossil resource scarcity
Suspension
Rim
magnesium cast alloy, coal gas usage
18
Water Consumption
HV
Battery packet
copper electrorefining
As can be seen from Table 3, of the 18 impact categories analysed, the greatest impact was recorded in the suspension and high-voltage components. (The contribution of all the assemblies of eVarta may be found in Fig. 9, and all the parts for both the most contributing assemblies are presented in Figs. 18 and 20.) When analysing the processes and resources included in these subassemblies, one can notice the following.
(1)
The use of aluminium and all the associated processing, which usually are connected with high energy consumption—caused by manufacturing of front or rear uprights or elements with similar manufacturing path, but these two are the most important in consideration of their unit mass,
(2)
The use of magnesium alloy for manufacturing the Rims set, which shows a high impact mainly on global warming, ozone formation or ionising radiation,
(3)
In the high-voltage group, the battery packet, which contains multiple lithium battery cells, is introducing the strongest impact across all the recorded results. The main reasons for this are the processes associated with copper or graphite production. The difference is noticeable for the ozone depletion category, where an important input from gold mining activities involvement has been traced,
(4)
For the marine eutrophication category, the engine was the leading component, with the great importance of extraction of rare earth concentrates within permanent magnet production.
When all elements of the life cycle are evaluated (with exclusion of end-of-life stage, as stated in the assumptions in Section "Methods"), the significant impact of the transportation factor is evident. For almost half of the impact categories investigated (global warming, stratospheric ozone depletion, ozone formation (both human health and terrestrial ecosystems), land use, and fossil resource scarcity), transportation activities play a crucial role in the contribution to the results. This fact is related to the specifics of the project: the vehicle, which is a prototype build, used for competition purposes by a group of students, requires more resources for relocation (long distances) than the energy input required to power it during competition or testing. As mentioned in the assumptions, the relocation processes were carried out using a diesel-powered LCV with emission levels meeting the EURO6 standard.
In Fig. 23, the graphical representation of the comparison between three different transportation scenarios is shown, where:
Scenario 1 stands for the basic assumption of 1500 [t x km]—a distance covered with 12 trips to track tests—a total of 300 km, and 2 trips for races (459 km to Autodrom Most Czechia and 459 km back; 891 km to Hockenheim Ring Germany and 891 km back),
Scenario 2 with an extended transport quantity of 2000 [t x km]—distance covered with 12 trips to track tests—a total of 300 km, and 2 trips for races (459 km to the Most Czechia Autodrom and 459 km back; 1391 km to the Riccardo Paletti Circuit Italy and 1391 km back),
Scenario 3 with an extended transport quantity of 2500 [t x km]—distance covered with 12 trips to track tests—a total of 300 km, and 2 trips for races (459 km to Autodrom Most Czechia and 459 km back; 1459 km to Silverstone Circuit UK and 1459 km back).
Fig. 23
Comparison of transportation scenarios in the eVarta lifecycle
×
In each scenario, the estimated payload (encompassing the race car, spare parts and charger, additional tyres, and servicing equipment) is equal to 0.5 t.
The purpose of this analysis is to determine the possible effects of assumed quantities by examining the different scenarios or variants within the selected stages of the product lifecycle.
By setting the differentiated transportation scenarios, it was possible to screen the sensitivity of the results and calculate the relative differences in the indicators of the impact of global warming, as presented in Table 4. It is possible to conclude that the transportation stage has considerable relevance, as seen in Scenario 3, and can prevail over the manufacturing stage within the results of the global warming indicator. The relative differences between scenarios vary up to 20% over the initial assumption.
Table 4
Environmental impact of the eVarta race car transportation scenarios: characterised results, ReCiPe 2016
Scenario 1
Scenario 2
Scenario 3
Unit
Characterisation results for different scenarios (global warming impact)
eVarta
4411.64
4411.164
4411.64
[kg CO2 eq]
Electricity, low voltage (use stage)
679.33
679.33
679.33
Transport, freight, light commercial vehicle
2772.05
3696.07
4620.08
Charger
175.47
175.47
175.47
Spare parts
1152.06
1152.09
1152.09
Total
9190.57
10,114.59
11,038.6
Relative difference
–
10
20
[%]
The LCIA results obtained are consistent, while the assumptions made in terms of the data collection phase and the way of modelling the object made it possible to achieve the discussed conclusions. The results of the hotspot analysis also show logical consistency with the assumptions and compliance with the project-specific framework and its unique, single-unit nature, especially by analysing all of the lifecycle components.
The authors understand that the presented structure of the obtained results is unusual in all aspects, compared to the vast majority of case studies concerning life cycle analyses of vehicles using various forms of electricity for propulsion. In these studies—e.g. comparisons of the life cycle impacts of electric vehicles and combustion engines (Pero et al. 2018a), most of the case studies reported in the review works of Nordelöf et al. (Nordelöf et al. 2014) and Idris (Idris and Koestoer 2023)—it is reported that the production and use of electricity to power vehicles during use are the source of the most serious environmental impacts. Moreover, most of the case studies present a well-to-wheel approach, where the main attention is paid on the production and use of energy needed to power during use.
In this case study, the greatest impacts are related to the eVarta manufacturing stage and its transport to testing and racing sites. This is because—unlike the commercial road vehicles analysed in most case studies, whose main task is to transport passengers (and goods)—the eVarta is a racing car that runs (and therefore is powered) only on the track, during testing and races, while all distances between the location and the race tracks are covered loaded on board of another vehicle (LCV). It should be noted that during the literature review, no case studies were found dedicated to LCA of racing vehicles. The only analysis found concerns a racing car designed and built by students of the Università degli Studi di Padova, but powered by an internal combustion engine, and does not include the stages of operation (e.g. expenditures related to fuel consumption) and transport.
Conclusions
This research delves into the life cycle assessment (LCA) of a Formula Student racing vehicle, with the aim of spotlighting principal environmental concerns. The study's objectives included the establishment of fundamental assumptions, emphasising meticulous data collection, aggregation, and classification. The primary objectives were met successfully, along with addressing the additional facets of the study. The results obtained were instrumental in discerning environmentally critical systems, and the subsequent analysis phases underscored the salient issues in project data administration, data voids, and iterative assumptions.
A significant outcome was the delimitation based on the functionality of the component groups and their alignment with the design team's organisational makeup. The data representation offers a comparative impact view for each category. This ranges from overarching assemblies and their environmental contributions to an intricate breakdown of every component constituting the vehicle's functional zones.
When evaluating all stages of the life cycle, the transportation stage emerges as a dominant factor affecting the results, as corroborated through varied scenarios presented in the sensitivity analysis focussing on the category of impact of global warming. A detailed assessment of the component groups revealed the pronounced environmental footprint of materials such as aluminium and aluminium–magnesium alloys, the procedures associated with their processing, and the processes related to lithium battery cells and copper production.
A proposed enhancement is the incorporation of manufacturing data within a 3D CAD model to streamline and standardise the information flow regarding parts fabrication. A pivotal consideration involves embedding additional attributes to all components, encompassing material characteristics and weight. Such attributes can be enriched by introducing supplier details, categorisation of the part (be it be outsourced or internally produced), or the specific material utilised. Often, procuring direct information on processes and materials from layout or component manufacturers proves challenging, necessitating reliance on generic data. Further recommendation:
Enhance the production methods of the traction battery to minimise environmental harm,
Explore eco-friendly substitutes for constructing the vehicle's chassis and exterior,
Implement advanced features like energy recovery during braking to boost the vehicle's ecological efficiency.
As mentioned, this case study concerns a customised vehicle, made in one piece and intended for very specific tasks. However, it is worth noting that in the case of such a rapidly developing economic sector as transport and the use of electric vehicles, the results of environmental analyses may quickly become outdated with the development of new, more efficient, and more environmentally friendly materials and production technologies and, above all, energy storage.
Most of the authors of case studies on electric vehicles and review works in this field (e.g. (Pero et al. 2018a; Bieker 2021; Alanazi 2023; Nordelöf et al. 2014; Idris and Koestoer 2023; Cox et al. 2018, 2020)) report that the main factor influencing the environmental nuisance of the use of electricity in vehicle drives is the way of its production, which is highly dependent on the energy mixes used. In addition, Nordelof et al. (2014) point out that most case studies lack a prospective vision.
In this light, it seems rational to postulate the repetition of eVarta racing car (or its successors) environmental analyses in the perspective of several years, taking into account the variable and changed conditions regarding the currently diagnosed hotspots (including the use of electricity and transport processes). Since a dynamic expansion of electric vehicles is currently observed in Poland (as in the whole world), the next version of the case study could include the realisation of transport processes of the eVarta racing car using a light commercial vehicle powered by this medium. It is also possible, as reported in Spreafico et al. (2023), to use methods based, among others, on patent analysis techniques, in order to include the potential information found in specific forms of documentation in the LCI process.
Declarations
Competing interests
The authors declare no competing interests.
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