A Comprehensive Sustainability Assessment of Battery Electric Vehicles, Fuel Cell Electric Vehicles, and Internal Combustion Engine Vehicles through a Comparative Circular Economy Assessment Approach

Abstract

Transitioning to zero-emission vehicles (ZEVs) is thought to substantially curb emissions, promoting sustainable development. However, the extent of the problem extends beyond tailpipe emissions. To facilitate decision-making and planning of future infrastructural developments, the economic, social, and technological factors of ZEVs should also be addressed. Therefore, this work implements the circular economy paradigm to identify the most suitable vehicle type that can accelerate sustainable development by calculating circularity scores for Internal Combustion Engine Vehicles (ICEVs) and two ZEVs, the Battery Electric Vehicles (BEVs), and Fuel Cell Electric Vehicles (FCEVs). The circularity assessment presents a novel assessment procedure that interrelates the environmental, economic, social, and technological implications of each vehicle type on the three implementation levels of the circular economy (i.e., The macro, meso, and micro levels). The results of our analysis suggest that not all ZEVs are considered sustainable alternatives to ICEVs. BEVs scored the highest relative circularity score of 36.8% followed by ICEVs and FCEVs scoring 32.9% and 30.3% respectively. The results obtained in this study signify the importance of conducting circular economy performance assessments as planning tools as this assessment methodology interrelate environmental, social, economic, and technological factors which are integral for future infrastructural and urban planning.

1. Introduction

The transportation sector is solely responsible for over a quarter of the Greenhouse Gases (GHG) emitted globally [1]. In the United States (U.S.), transportation is responsible for the largest portion (29%) of the total GHG emissions, out of which 58% are emitted by Light Duty Vehicles (LDVs) (i.e., passenger vehicles and light trucks) [2]. In addition to their direct contribution to global warming, some GHG and other LDVs’ emissions, such as nitrogen oxides, sulfur oxides, ozone, volatile organic hydrocarbons (VOCs), and particulate matter (PM_2.5 and PM₁₀), have been proven to cause direct health implications for humans [3]. It is estimated that air pollution will cause 6 to 9 million premature deaths annually and 176 billion USD in healthcare spending by 2060 [4]. In terms of energy, the transportation sector is responsible for 26% of the total energy consumption in the U.S., of which more than 55% is driven by LDVs [5]. These figures are mainly caused by the intensive use of fossil fuels in the automotive industry, since more than 90% of LDVs in the U.S. are conventional Internal Combustion Engine Vehicles (ICEVs) running on fossil fuels (i.e., gasoline, petroleum, or diesel) [6].

As a natural progression of the efforts spent on suppressing the aforementioned effects of conventional ICEVs, and to meet the Paris Agreement’s global target of maintaining the increase in the global average temperature below 2 °C [7], alternatives to ICEVs have emerged in the automotive industry. Zero Emission Vehicles (ZEVs), such as Battery Electric Vehicles (BEVs) and Fuel Cell Electric Vehicles (FCEVs), have been heavily advertised as the solution to mitigate climate change and the rapid resource uptake caused by the use of ICEVs [8]. However, this might not always be true. Statistics mentioned earlier have been sought to represent the impact of LDVs on the environment, the economy, and the public. However, they only present a fraction of the actual impacts of LDVs. Direct emissions are the main drivers of these numbers. While emissions produced and resources consumed during upstream processes, such as the production of fuel and materials, are usually not accounted for and are categorized along with other industrial categories. As a result, the negative impacts of some ZEVs may be equal to, if not greater than that of conventional ICEVs. There are growing concerns over indirect emissions produced during the upstream and downstream processes involved in the production of the electricity and batteries used in ZEVs [9].

In addition to indirect emissions, several other factors play an important role in determining the most adequate vehicle technology that is to be adopted to accomplish the Paris Agreement’s targets and other local and global initiatives aiming to suppress global warming and achieve the three sustainability pillars (i.e., environmental, economic, and social developments [10]). For example, users are directly influenced by incentives and both the initial and running costs of the vehicles. Thus, it is crucial to take these factors into consideration when conducting assessments as the will influence the adoption rate of ICEV alternatives in the coming years. Life Cycle Assessments (LCAs) performed on ICEVs, BEVs, and FCEVs present the preferred vehicle type from one perspective only: the environmental perspective. In this perspective, the type that emits the least amount of greenhouse gasses and consumes the least amount of energy and water during its life cycle is preferred [11,12]. However, there are several other factors that need to be taken into consideration for policymakers to make informed decisions to achieve carbon neutrality and sustainable development. As a solution, this work aims to utilize the Circular Economy (CE) paradigm by conducting a novel circularity assessment to obtain a single score (i.e., circularity score) that represents the CE performance of the vehicles.

The Circular Economy (CE) is a conservative system intended to replace the current linear model [13]. It aims to enable energy decarbonization by exclusively using clean energy sources and promote the circularity of materials by limiting the use of raw materials through the high-quality recycling of components and products and limiting waste generation by extending the lifetime of products [13]. Along with its environmental benefits, the CE model positively enhances economic growth and social development [14]. Economically, applying a CE model decreases the geopolitical interconnectedness of materials and products, in which a scarcity of one material causes a scarcity of another, resulting in economic instability within nations [15]. Socially, by applying the CE model, the cost of products can be cut by up to 30%, thereby lowering consumer spending [14]. Unlike conventional LCAs, assessing a vehicle based on how circular it is gives us a comprehensive indication of its overall environmental, economic, and social performances along the different stages of its life cycle, beginning with resource uptake and ending with recycling. Indicators used in the circularity assessments are of three CE implementation levels: the macro, meso, and micro. Macro indicators collect data on an international or national level, the meso indicators gather this information that is of societal interest on a national level, and micro indicators target users, products, and services [16]. With the limited resources, and the growing complications caused by pollution and global warming, a circularity assessment of LDVs is crucial to determine the strategies and policies needed to accelerate sustainable development.

In this work, ICEVs, BEVs, and FCEVs are assessed in terms of circularity using a number of indicators that captures the different stages of each vehicle type on the macro, meso, and micro levels of CE implementation. The paper is divided as follows. Firstly, a literature review section is presented to review the different assessments conducted on the three vehicle types by the scientific community. This is followed by the methods section which presents how the selected indicators’ data are obtained and the methods used to conduct the circularity assessment. Lastly, the results of the circularity assessment are presented and discussed in the results and discussion section followed by a conclusion summarizing the important findings of this work.

2. Literature Review

The concept of circularity has been linked to the automotive industry on a few occasions in the literature. Martens et al. developed a model to support the development of a full circular vehicle. The authors defined 15 different circular practices to promote the development of the circular vehicle concept [17]. Moreover, Bobba et al. used material flow analysis (MFA) coupled with LCA to study the effects of remanufacturing and other resource-efficient strategies in the automotive industry on the materials and the environment [18]. Results showed that the materials cause the highest amount of emissions when compared to energy and shredding that occurs at the end of the life of the vehicle. While MFA results showed that remanufacturing can contribute to the circularity of LDVs by allowing 150,000 tonnes of materials to circulate within the economy.

The literature lacks assessments based on the circularity of ICEVs, BEVs, and FCEVs. The assessments present in the literature often utilize LCA methods to assess the vehicles based on their environmental impacts. This was captured in several papers that have conducted LCAs on BEVs [19,20,21,22]. Additionally, the material footprint LCA (MF-LCA) method was used to assess the environmental impacts of BEVs from the materials perspective [23]. Similarly, other papers have assessed the environmental impacts of BEVs and compared them to that of ICEVs using LCA [24,25,26,27]. In addition to the environmental impacts, some papers have assessed the economic aspects of BEVs as well. For example, one study investigated the possible positive environmental and economic impacts of the adoption of BEVs in the U.S. [28]. Similarly, another paper conducted a techno-economic and environmental impact analysis on BEVs using Life Cycle Cost Analysis (LCCA) [29]. Moreover, Ajanovic and Hass reviewed the economic and environmental prospects of both BEVs and FCEVs [30]. Similarly, Miotti et al. assessed FCEVs and compared them to BEVs and ICEVs from environmental and economic perspectives [31]. Others focused on the economic aspect alone. For example, one study revealed that consumers in the U.K. can save up to 35% per annum on electricity bills by using a BEV [32].

The social impacts of the vehicles have been either studied alone, or along with the economic impacts, as both pillars have several mutual indicators such as the initial and running costs. Some papers have assessed or investigated the social aspects alone of BEVs and FCEVs [33,34]. Very few papers have assessed the vehicles from the environmental, economic, and social perspectives together. For example, Wang et al. conducted a comprehensive evaluation of the sustainable development of BEVs versus ICEVs in China using Life Cycle Sustainability Assessment (LCSA), LCA, Life Cycle Costing (LCC), and Social Life Cycle Assessment (SLCA) [35]. However, the study excludes FCEVs and neglects the fuel life cycle in the assessment. Additionally, few works assessed the three types of vehicles at once. Wong et al. used LCA to compare the environmental impacts of ICEVs, BEVs, and FCEVs [36].

Table 1. A review of the different types of assessments conducted on ICEVs, BEVs, and FCEVs from the literature.

Reference	Assessment Type	Vehicle(s) Assessed			Sustainability Pillar(s) Targeted
		ICEV	BEV	FCEV	Environment	Economy	Society
[19]	LCA		✓		✓
[20]	LCA		✓		✓
[21]	LCA		✓		✓
[22]	LCA		✓		✓
[23]	MF-LCA		✓		✓
[24]	LCA	✓	✓		✓
[25]	LCA	✓	✓		✓
[26]	LCA	✓	✓		✓
[27]	LCA	✓	✓		✓
[28]	Other		✓		✓	✓
[29]	LCCA		✓		✓	✓
[30]	Review		✓	✓		✓
[31]	LCA	✓	✓	✓		✓
[32]	Other		✓			✓
[33]	Other		✓				✓
[34]	Other		✓	✓			✓
[35]	LCSA, LCA, LCC, SLCA					✓	✓
[36]	LCA	✓	✓	✓		✓

summarizes the aforementioned literature review by indicating the type of vehicle(s) assessed and the sustainability pillar(s) targeted by each assessment.

It can be noticed from the conducted literature review that most assessments conducted utilized LCA methods. While none has assessed ICEVs, BEVs, and FCEVs in terms of circularity. In other words, the literature lacks an assessment procedure that can establish a comprehensive score that can provide policymakers with a concise indication of the overall environmental, economic, and social performances of each vehicle type on the macro, meso, and micro implementation levels of the circular economy. Other gaps include the exclusion of upstream processes involved in the production of fuels (i.e., gasoline, electricity, and hydrogen), transportation of resources and fuels during the well-to-pump phase (Macro to meso phase), and the direct social and economic impacts on end-users. Thus, this work aims to present a comprehensive assessment that compares ICEVs, BEVs, and FCEVs from the circular economy perspective to obtain a comprehensive circularity score for each vehicle type. The assessment is carried out on the three implementation levels of the CE, the macro, meso, and micro levels. These levels cover all stages along the lifetime of the vehicles beginning with resource uptake and ending with recycling. The circularity scores obtained, thus, provide a holistic overview of the vehicles’ sustainability performance as it takes the environmental, economic, and social aspects into consideration. As a result, these scores provide policymakers and end-users with a meaningful reference that they can rely on to take impactful decisions targeting the achievement of sustainable development.

3. Materials and Methods

This section presents the methodology for obtaining the data associated with the indicators selected. In this work, we assess the relative circularity of ICEVs versus BEVs versus FCEVs, by analyzing a number of selected indicators that measure individual vehicles’ environmental, economic, and social impacts on the macro, meso, and micro implementation levels as presented in Figure 1, to determine the most adequate vehicle technology that would facilitate our transition to a carbon neutral and a sustainable future. The procedure of indicators selection is based on a multi-level circular economy assessment framework by [37]. The analysis will cover 10 years of operation to account for FCEVs which have a relatively lower lifetime compared to ICEVs and BEVs. Yet, the lifetime of each vehicle will be taken into consideration during the assessment. Additionally, the analysis will be based on an expected driving range of 23,013.6 km per year [38], and will be carried out on sedan/wagon-type vehicles. The average fuel consumption of an ICEV used throughout the analysis is 10.93 km per liter [39]; this translates to a total of 21,055.4 L used during the assessment period. The electricity consumption of a BEV is taken as 18.95 kWh per 100 km [40], translating to a total of 43,610.8 kWh. Similarly, the hydrogen consumption of an FCEV is taken as 1.02 kg per 100 km [41] resulting in a total of 2347.4 kg of hydrogen consumed during the assessment period. These parameters are presented in

Table 2. Fixed parameters used throughout the analysis.

Parameter	Value Used in the Study	Reference/ Assumption
Distance driven	230,136 km	[38]
Fuel consumption (E10)	21,055.4 L	[39]
Electricity Consumption	43,610.8 kWh of electricity	[40]
Hydrogen Consumption	2347 kg of hydrogen	[41]

.

The indicators selected are the ones that showed significant variation between the three vehicle types only. Other indicators that showed slight or no variations were eliminated. For instance, the assembly and distribution of the vehicles are two integral stages within the CE. However, their influence on the results is negligible since these stages are almost identical for the three vehicle types. As well, the different amounts of money spent along the supply chain including upstream processes are considered to be carried over to the total cost of operation. It should be noted that emissions here refer to carbon dioxide (CO₂), volatile organic compounds (VOCs), carbon monoxide (CO), nitrogen oxides (NO_x), particulate matter (PM_2.5 and PM₁₀), sulphur oxides (SO_x), methane (CH₄), black carbon (BC), and primary organic carbon (POC). However, CO₂ is the most dominant emission produced with a weight percentage of more than 98%, which means that more than 98% by weight of the emissions produced are composed of CO₂. The following section presents the methodology used to obtain the indicators’ data. The selected indicators categorized by the three sustainability dimensions are presented in Figure 2.

3.1. Macro Level Indicators

Macro-level indicators mainly focus on collecting parameters associated with the upstream processes on both the national and international levels and are involved in the production of fuels and materials used in the vehicles and the batteries. Indicators are collected to account for the energy consumed (energy demand) and water consumed (water footprint) and the emissions produced during production stages and during transportation. These indicators were collected by conducting analyses on the GREET software that was developed by the Argonne National Laboratory (ANL), a U.S. Department of Energy (DOE) multidisciplinary science and engineering research center [42].

3.1.1. Fuel Production

This section presents the different Macro level indicators associated with the production of the different fuels used by the assessed powertrains using data generated by the GREET software. These fuels are gasoline (E10) for ICEVs, electricity for BEVs, and hydrogen for FCEVs. The indicators obtained are mainly energy consumed, water consumed (water footprint), and emissions produced by the production of each fuel.

Gasoline: Almost all the gasoline sold in the U.S. is 10% ethanol (E10) by volume [43]. Thus, the analysis carried out will consider E10 as the fuel used for ICEVs. The upstream processes involved in the production of E10 are presented in Supplementary Figure S1. The U.S. refineries produce crude oil from a mixture of conventional crude oil, synthetic crude oil, bitumen, and shale oil. Gasoline is then refined from the crude oil produced and the gasoline blendstock is transported to bulk terminals. Gasoline blendstock is mixed with denatured ethanol to produce reformulated gasoline (E10). The analysis considered all upstream processes, such as ethanol production from different sources, as highlighted in Supplementary Figure S1. Different transportation processes were also taken into consideration when calculating the total resources consumed and emissions produced. Supplementary Table S1 presents a breakdown of the emissions produced and the resources consumed by the upstream processes involved in the production of crude oil in U.S. refineries. This was obtained by running the GREET model for the specified processes. The production of one liter of E10 consumes approximately 11.76 kWh of energy and produces around 0.562 kg of different emissions. For the defined fuel consumption (i.e., 10.93 km per liter) and the distance travelled during the assessment period (i.e., 23,036 km), 21,055.5 L of E10 are consumed. Thus, an ICEV’s lifetime fuel consumption produces around 11.8 tonnes of different emissions and consumes 124.35 m³ of water and 247.59 MWh of electricity. A further breakdown of the findings is presented in Supplementary Table S2.

Electricity: The emission factors are based on EPA and EIA databases, while the types of electrical generation are taken to be the typical U.S. mix, which consists of 39.57% natural gas, 20.42% nuclear power, 19.50% coal, 8.89% wind power, 7.37% hydroelectric power, 2.22% solar power, 0.47% biogenic waste, 0.40% geothermal power, 0.37% oil-fired power, and 0.32% biomass, as presented in Supplementary Figure S2 [44]. It is presumed that the electricity is transmitted and distributed to charging stations with an efficiency of 95.12%. According to the conducted GREET analysis, the generation of one kWh of electricity from the sources stated earlier requires 2.05 kWh of energy, consumes 2350.64 cm³ of water, and produces 0.412 kg of emissions. A BEV consumes about 43,615 kWh of electricity during the assessment period (i.e., 10 years). As a result, the electricity required over the lifetime of a BEV consumes about 89 MWh of electricity and 102.5 m³ of water and produces 17.97 tonnes of emissions. A further breakdown of the findings is presented in Supplementary Table S3.

Hydrogen: In the United States, 95% of the hydrogen is produced from reforming natural gas [45]. Thus, the analysis was conducted on the process of obtaining hydrogen from natural and shale gases as presented in Supplementary Figure S3. The production of 1 kg of hydrogen consumes around 120.6 kWh of energy and 20,660.2 cm³ of water and produces 11.64 kg of emissions. Thus, the production of hydrogen used by an FCEV during the assessment period (i.e., 2347.4 kg in 10 years) consumes 134.52 MWh of electricity and 48.5 m³ of water and produces around 27.32 tonnes of different emissions. A further breakdown of the findings is presented in Supplementary Table S4.

3.1.2. Vehicle Components Material Production

This section presents a breakdown of the emissions produced, and the resources consumed from the production of materials used in manufacturing each vehicle’s components. The vehicle components considered are the vehicle’s body, powertrain, transmission system/gearbox, and chassis, as well as the traction motor, generator, electronic controller, and fuel cell onboard storage, if applicable. According to the analysis conducted on GREET, it is assumed that the ICEV weighs approximately 1386 kg, the BEV weighs 1315 kg, and the FCEV weighs 1670 kg. This excludes the weight of the batteries. A breakdown of the composition of the main materials used in the manufacturing of each vehicle is presented in Supplementary Table S5. Upstream processes involved in the production of the main materials used in the manufacturing of the components of the three vehicles are presented in Supplementary Figures S4–S13. Energy and water consumed, and the emissions produced during the production of each material are recorded in Supplementary Tables S6–S19. The analysis shows that production of the materials involved in the manufacturing of FCEVs consumes the most energy and water and produces the largest amount of emissions compared to ICEV and BEV materials.

3.1.3. Battery Production

Batteries vary depending on the vehicle type. ICEVs are equipped with lead-acid batteries while BEVs and FCEVs are equipped with lithium-ion (Li-ion) batteries and nickel metal hydride (Ni-MH) batteries respectively, in addition to the lead-acid battery. The lead-acid battery weighs 16.3 kg for the ICEV, and 10 kg for both the BEV and FCEV, while the Li-ion batteries weigh 397.6 kg in a BEV, and the Ni-MH battery weighs 47.9 kg in a FCEV. A breakdown of the main materials used in the manufacturing of the batteries is presented in Supplementary Table S20.

Lead-Acid Battery: The emissions released, and the energy and water consumed by the production of the lead-acid battery materials, which are listed in Supplementary Table S20, were then gathered and summarized in Supplementary Table S21. An analysis shows that the production of the materials used in a single lead-acid battery in an ICEV consumes 55.1 kWh of energy and 19.6 m³ of water and emits 7.5 kg of emissions, while the smaller lead-acid battery used in both BEVs, and FCEVs consumes 33.5 kWh of electricity and 12 m³ of water and emits 3 kg of emissions.

Lithium-ion Battery: The emissions released, and the energy and water consumed by the production of the materials for the Li-ion batteries, which are listed in Supplementary Table S20, are gathered and summarized in Supplementary Table S22. An analysis shows that the production of the materials used by a single lead-acid battery consumes 17.9 MWh of energy and 34.5 m³ of water and emits 4064.6 kg of emissions.

Nickel Metal Hydride Battery (NiMH): The emissions released, and the energy and water consumed by the production of the materials for the NiMH batteries, which are listed in Supplementary Table S20, are gathered and summarized in Supplementary Table S23. An analysis shows that the production of the materials used by a single nickel metal hydride battery consumes 1.4 MWh of energy and 1.8 m³ of water and emits 300 kg of emissions.

3.2. Meso Level Indicators

The emissions released, and the energy and water consumed by the production of the materials for the NiMH batteries, which are listed in Supplementary Table S20, are gathered and summarized in Supplementary Table S23. An analysis shows that the production of the materials used by a single nickel metal hydride battery consumes 1.4 MWh of energy and 1.8 m³ of water and emits 300 kg of emissions.

3.2.1. Number of Refueling Stations across the U.S.

Infrastructure readiness is presented through the number of refueling stations available across the U.S. for each vehicle type. Currently, there are more than 150,000 gasoline fueling stations for ICEVs [46], 46,067 electric charging stations for BEVs [47], and only 48 hydrogen refueling stations for FCEVs out of which 47 are located in California and one in Hawaii [47].

3.2.2. National Incentives

Incentives are a strategy that promotes the adoption of certain technologies that are of national significance. There are about 286 different initiatives that target BEV users and 35 that target FCEV users across the different states [48]. In contrast, a federal law has been introduced to phase out the sale of any non-zero emission vehicles, such as ICEVs, by 2035 [49].

3.2.3. Recyclability Rate

Recyclability percentage here refers to the percentage of materials that can be reclaimed and reused after being recycled. Since the materials used to manufacture the main components of the three vehicles are similar, we will only consider the power source of each vehicle which are the internal combustion engine (ICE), the Li-ion batteries, and the fuel cells. By referring to the GREET database, 42.4% of the components of an ICE are made up of steel, 27% are made of aluminum, 19% are made of plastic, 6.8% are made up of copper and the rest consists of other components, such as rubber, in smaller quantities. Since steel, aluminum, and copper are recyclable, it can be said that around 76% of the engine is recyclable [50,51,52]. According to some recent life-cycle analyses, the recycling of lithium-ion batteries is not yet an attractive option for electric car manufacturers due to the low economic value of the batteries. Additionally, a similar percentage, if not more, of greenhouse gas emissions are produced compared to primary production [53]. However, companies working on Li-ion recycling state that they can recover up to 95% of all basic materials found in lithium-ion batteries [54,55,56]. Similarly, in the case of a fuel cell, a source states that more than 95% of the membrane electrode assembly of the precious metals in a fuel cell could be reclaimed by recycling [57].

3.3. Micro Level Indicators

Micro-level indicators are indicators that represent the products and the users. For example, the users are directly affected by the total cost of operation, while some of the product’s characteristics are its efficiency and lifetime.

3.3.1. Total Cost of Operation

The total cost of operation (TCO) for different car types varies. A breakout of the TCO proposed by Liu et al. (2021) [58] divides the TCO into two main cost categories. The first category is the capital cost (initial cost), which is the summation of the vehicle’s price, initial registration fees, and home charger costs in the case of BEVs. The second category is the annual operation costs, which cover the repair and maintenance costs, fuel consumption costs, insurance costs, annual registration fees as well as additional state fees for BEVs and FCEVs [58]. In this analysis, the TCO will consist of six sub-indicators: the capital cost, energy costs, insurance costs, registration and state fees, maintenance and repair costs, and the home charging installation cost if applicable.

Capital cost (powertrain cost): The capital cost presented is the cost of the powertrain of each type of vehicle. Capital costs obtained from the literature are 14,317 USD for an ICEV, 23,805 USD for a BEV, and 20,523 USD for an FCEV [59].

Energy cost: Energy costs are represented by the current average gasoline cost for ICEVs, electricity cost for BEVs, and hydrogen cost for FCEVs. The prices of energy sources were assumed to be fixed throughout the assessment period, due to the unpredictable volatile price changes of gasoline and other energy sources. An ICEV would consume 5564.2 gallons (21,055.4 L) of gasoline during the assessment period. With a 10-year average gasoline price of 3.18 USD per gallon [60], the energy cost for ICEVs is approximately 17,694.17 USD, while the average price of electricity is 0.1157 USD per KWh [61]. Thus, the total cost of electricity used by a BEV would be approximately 5046.256 USD. Finally, with the current hydrogen price of 16.51 USD per kilogram, running an FCEV would cost 38,695.64 USD during the assessment period [62].

Insurance cost: Vehicle insurance is usually estimated based on many factors, such as the vehicle type, driver’s age, driving history, credit score, and annual milage. The insurance costs presented in this section are an estimated average from different providers filtered from Supplementary Table S24. Five out of the most common insurance providers in the U.S. were selected from the table. The selected insurance providers covered all states in addition to Washington D.C. and have an average customer satisfaction rating of four and above on a scale of five. Based on the estimated average insurance costs provided in Supplementary Tables S25–S27 and assuming a constant insurance rate throughout the 10 year period, the insurance costs are estimated to be 13,968 USD for an ICEV, 21,471 USD for a BEV, and 20,648.4 USD for a FCEV.

Registration and state (R and S) fees: The average state fees vary across the different states. Usually, BEV owners are charged more than ICEV owners. At the current time, there are no direct state fees specified for FCEVs. This is mainly due to the modest market for FCEVs that is limited to California. However, a few states categorize FCEVs as a hybrid vehicle. This includes South Carolina and West Virginia, where they impose an additional 60 USD and 100 USD respectively [63]. Additionally, FCEVs can be categorized under alternative fuel vehicles in other states such as Georgia, Missouri, and Virginia. Hence the average state fees of FCEVs were determined based on the abovementioned states. According to the data obtained from the National Conference of State Legislature (NCSL), which is summarized in Supplementary Table S28, the average state fees imposed on ICEVs, BEVs, and FCEVs are 655.65, 1370.11, and 1417.13 USD respectively [63,64].

Maintenance and repair (M and R) costs: The maintenance and repair of vehicles are directly influenced by the powertrain type. For instance, unlike electric motors, internal combustion engines require consumables such as engine oil, oil filters, engine air filters, and fuel filters to maintain a smooth and fault-free operation during the vehicle’s lifetime. An analysis of the scheduled maintenance costs per milage conducted by Argonne National Laboratory showed that maintenance costs for BEVs were approximately 40% less compared to ICEVs [65]. Given that FCEVs are similar to BEVs in that they do not have many moving parts, a similar cost breakdown for FCEVs was conducted and presented in Supplementary Table S29. The results show that both BEVs and FCEVs cost approximately the same with a small variation due to the smaller battery size of the FCEV. Results of the analysis show that the scheduled maintenance of ICEVs is the most expensive costing approximately 14,014 USD. In contrast, it costs BEV and FCEV owners 8294 USD and 8151 USD respectively. According to the ANL, the repair cost per mile in a given year can be calculated by taking into consideration the vehicle type, powertrain type, and the manufacturer-suggested retail price (MSRP) in the year in which a new vehicle was sold [65]. Using the data presented in Supplementary Table S30, the repair costs of an ICEV, BEV, and FCEV are 2583.60 USD, 2903 USD, and 1946 USD respectively.

Home charging installation (HCI) costs: Home charging installation is an optional one-time fee that applies to BEVs only. The charging equipment is classified into three levels based on the rate of charging. Level 1 charges 2 to 5 miles of range per 1 h of charging, Level 2 provides 10 to 20 miles of range per 1 h of charging, while Level 3 (DC fast charging) provides 60 to 80 miles of range per 20 min of charging [66]. Homes are usually equipped with either Level 1 or Level 2 charging equipment, which can cost from 813 USD to 3127 USD [67]. For this analysis, an average of 1970 USD was considered.

3.3.2. Vehicle’s Lifetime

One of the main goals of CE is to enhance the product’s lifetime in order to decrease resource uptake; hence, the vehicle’s lifetime is an important factor to be considered when conducting circularity assessments. The lifetimes of the vehicles are determined based on the lifetimes of the main components of each vehicle’s powertrain. That includes the ICE for the ICEVs, the lithium-ion battery for the BEVs, and the fuel cells of the FCEVs. The lifetime of each component in years is determined by dividing the driving range capacity for each vehicle type, by the average distance driven per year (i.e., 23,014 km/year). While a fuel cell can last up to 150,000 miles (241,402 km) [12] which translates to around 10.5 years, the lifetime of the lithium-ion battery pack of a BEV is influenced by charging/discharging rates, overcharging, and climate conditions [68]. Most BEV manufacturers offer a 100,000-mile (160,934.40 km) warranty for their batteries [69]. In ideal conditions, batteries can last for a long time as degradation occurs gradually over the years. Thus, a BEV battery can last for up to 200,000 miles (i.e., 321,868.80 km) or 14 years. Similarly, a well-maintained ICE can last for more than 200,000 miles or 14 years [70].

3.3.3. Refueling/Recharging Time

Long refueling and recharging times can cause delays in our daily schedule to a point where it can be considered a burden and an extra cost for users. Thus, it is very important to consider the time it takes to refuel or recharge each vehicle in the assessment. Across the U.S., there are almost 46,067 electric charging stations providing around 114,858 units of electric vehicle supply equipment (EVSE). Out of these EVSE, 19.7% are DC fast chargers. Only 1% are Level 1 chargers, while 79.3% are Level 2 chargers [47]. Thus, Level 2 EVSE, which have an average charging time of 2–3 h, were used in the analysis as the standard means of charging BEVs [71]. In comparison, it takes around 2–3 min to refuel ICEVs and FCEVs [30,72].

3.3.4. Tailpipe Emissions

Both BEVs and FCEVs do not produce any tailpipe emissions throughout their lifetime. ICEV tailpipe emissions depend on the fuel economy of the vehicle and the type of fuel used. For example, considering an ICEV running on gasoline with an average fuel economy of 25.7 mpg, the combustion equation would be as follows:

2C₈H₁₈ + 25O₂ → 16CO₂ + 18H₂O,

(1)

This indicates that for each mole of octane, eight moles of carbon dioxide are produced (114 g of octane produces 352 g of carbon dioxide). The density of gasoline is 739 g per liter; hence, the mass of gasoline required per mile is as follows:

$$\frac{1\mathrm{gallon}}{25.7\mathrm{miles}}\ast \frac{739\mathrm{grams}}{1\mathrm{Liter}}\ast \frac{3.785\mathrm{Liters}}{1\mathrm{gallon}}\ast \frac{25.7\mathrm{miles}}{41.36\mathrm{km}}=67.6\frac{\mathrm{grams}\mathrm{gasoline}}{\mathrm{km}}$$

(2)

Equation (2) aims to convert gallon/miles to grams/kilometer. The amount of CO₂ produced per mile is therefore 208.73 g per km, and 48,036 kg over 10 years.

3.3.5. Required Maintenance Frequency (RMF)

To ensure a fair comparison, the RMF was based only on the distinct powertrain components. Mutual parts, such as tires, brake pads, and cabin air filters were not considered. ICEVs required more frequent maintenance due to the presence of several consumable components. Such components include the engine oil and the oil filters, which require service every 12,000 km [65]. In comparison, the only consumable material in the powertrains of BEVs and FCEVs is the battery coolant, which is changed after 200,000 km [65].

3.3.6. Vehicle Efficiency

Each vehicle’s efficiency was calculated by determining the efficiency of the main driving component. These are electric motors for BEVs and FCEVs, and the ICE for ICEVs. Electric motors convert electrical energy to mechanical energy (motion) with an 85% efficiency compared to 40% for ICEs [73]. Hence, ICEVs, BEVs, and FCEVs can have a theoretical maximum efficiency of 40%, 85%, and 85% respectively, assuming no losses in the other powertrain components.

3.3.7. Energy Source Utilization

More than 77% of the electrical energy from the grid is converted to power at the wheels of BEVs [74]. Likewise, an FCEV system can utilize about 60% of the fuel’s energy [75], while only 12% to 30% of the energy stored in gasoline is converted to power to the wheels in ICEVs [74].

3.3.8. Range on Full Tank/Battery

ICEVs are equipped with a 50-L gasoline tank on average [76]. With an average fuel economy of 10.93 km per liter, a fully filled ICEV would cover 546.5 km. On average, the battery capacity of a BEV is 59.6 kWh [77]. For an average consumption of 18.95 kWh per 100 km, a fully charged battery would last for about 314.48 km. In contrast, an FCEV can cover an average of 584.19 km on a full tank of hydrogen [78].

3.3.9. Technology Readiness Level (TRL) Scale

The TRL is a scale developed by the National Aeronautics and Space Administration (NASA). It is used to assess where technology is on its journey from the initial idea to market on a scale of TRL 1 (the lowest) to TRL 11, (the highest) [79]. Lithium-ion batteries score an average of TRL 7 while a PEM fuel cell scores TRL 8 and an ICE scores TRL 9 [79,80].

3.3.10. Range Anxiety

Due to the relatively lower range of BEVs and the limited number of recharging stations, users tend to develop a form of psychological stress labeled as range anxiety [81]. Similarly, FCEV users face range anxiety due to similar reasons. In contrast, ICEV owners do not face such issues due to the fully developed fueling infrastructure. As mentioned earlier, BEV charging stations are currently being developed at a fast pace unlike hydrogen fueling stations. As a result, such anxiety would decrease over time for BEV owners. Hence, over a span of 10 years, range anxiety could be labeled as moderate for BEV owners, high for FCEV owners, and low for ICEV owners.

3.4. Circularity Scores Calculation

After all the indicators were collected, the values obtained are aggregated to be assessed using Multi-Criteria Decision-Making Methods (MCDMs). The qualitative indicator such as range anxiety can be converted to numbers in which low is changed to 100, medium to 50, and high to zero. Three MCDMs will be used to increase the accuracy of the results. The methods that will be used are the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS), the Grey Relation Analysis (GRA), and the Complex Proportional Assessment (COPRAS).

Regarding the TOPSIS method, firstly, a scoring matrix is constructed using the values obtained from the analysis as follows:

	Indicator 1	Indicator 2	Indicator 3	Indicator 4
ICEV (r = 1)	x11	x12	……	x1w
BEV (r = 1)	x21	x22	……	x2w
FCEV (r = 1)	x31	x32	……	x3w

The next step is to normalize the score matrix using the following Equation (3):

$${\overline{x}}_{rw}=\frac{x_{rw}}{\sqrt{{\sum }_{w=1}^m{x}_{rw}^2}}$$

(3)

where the alternative number is denoted by r and the indicator number is denoted by w, and m is the total number of indicators. In this study, the number of alternatives is three and the number of indicators is 22. However, as the scores of each implementation level are obtained separately, the number of indicators at the macro level is eight, the number of indicators at the meso level is three, and the number of indicators at the micro level is ten. The ideal best $(V_w^{+}$) and ideal worst ($V_w^{-}$) of each indicator are then obtained. For a beneficiary value such as efficiency, the ideal best is the maximum number and the minimum number is the ideal worst. However, for the non-beneficiary values such as emissions, the minimum number is the ideal best, and the maximum number is the ideal worst. The Euclidean distance from the ideal best and ideal worst are then obtained using the following Equations (4) and (5):

$$S_r^{+}={\left[\sum _{w=1}^m{\left(V_{rw}-V_w^{+}\right)}^2\right]}^{0.5}$$

(4)

$$S_r^{-}={\left[\sum _{w=1}^m{\left(V_{rw}-V_w^{-}\right)}^2\right]}^{0.5}$$

(5)

The performance scores are then calculated for each alternative (Vehicle type) using the following Equation (6):

$$P_r=\frac{S_r^{-}}{S_r^{+}+S_r^{-}}$$

(6)

Alternatives are ranked based on their performance scores where the highest scores are ranked the best. Refer to reference [82] for more details on the other MCDM methods (GRA and COPRAS) used.

4. Results and Discussion

This section summarizes the indicators obtained and presents the results of the MCDM methods that are used to calculate the final relative circularity scores and rank the vehicles accordingly.

4.1. Macro Level Indicators

As mentioned earlier, macro-level indicators are intended to calculate the energy and water consumed and the emissions produced during production stages and during transportation. The analysis conducted shows that a single ICEV’s lifetime fuel production produces around 11.8 tonnes of emissions and consumes 124.35 m³ of water and 247.59 MWh of energy. While the production of electricity for the lifetime of a single BEV consumes about 89 MWh of energy and 102.5 m³ of water and produces 17.97 tonnes of emissions. Lastly, the production of the hydrogen used by a single FCEV during the assessment period consumes 134.52 MWh of energy and 48.5 m³ of water and produces around 27.32 tonnes of emissions. The analysis showed that in terms of energy consumption, E10 and hydrogen production consume 247.6 MWh and 134.5 MWh of energy respectively compared to 89.26 MWh for electricity. In terms of water consumption, the production of E10 consumes 124.35 m³ compared to the 102.5 m³ and 50 m³ consumed by the production of electricity and hydrogen respectively. With regards to emissions, the production of hydrogen releases the most emissions: 25.14 tonnes compared to the 11.8 tonnes and 17.96 tonnes produced from the production of E10 and electricity respectively.

In terms of each vehicle component’s production, analysis shows that the production of the materials involved in the manufacturing of FCEVs consumes the most energy and water and produces the most emissions compared to the production of materials for ICEVs and BEVs. The production of materials used in FCEVs consumes 27.1 MWh and 33.5 m³ of water and produces 5.5 tonnes of emissions. In comparison, the production of materials used in BEVs requires 15.9 MWh and 22 m³ of water and produces 3.4 tonnes of emissions, and the production of materials used in ICEVs requires 17.4 MWh of energy and 25.7 m³ of water and produces 3.4 tonnes of emissions.

In terms of battery production, the production of the materials used by a single lead-acid battery in an ICEV consumes 55.1 kWh of energy and 19.6 m³ of water and emits 7.5 kg of different emissions. In comparison, the smaller lead-acid battery used in both BEVs, and FCEVs consumes 33.5 kWh of electricity and 12 m³ of water and emits 3 kg of different emissions. The production of the materials used by a single lithium-ion battery consumes 17.9 MWh of energy and 34.5 m³ of water and emits 4064.6 kg of different emissions. The production of the materials used by a single nickel metal hydride battery consumes 1.4 MWh of energy and 1.8 m³ of water and emits 0.3 kg of different emissions. A summary of the results in this section is presented in Figure 3, Figure 4 and Figure 5.

4.2. Meso Level Indicators

Meso-level indicators represent data that is of societal interest. In this analysis, three indicators were selected to represent the meso level. Firstly, the number of refueling stations across the U.S. is determined. Currently, there are more than 150,000 gasoline fueling stations for ICEVs, 46,067 electric charging stations for BEVs, and only 48 hydrogen refueling stations for FCEVs. Another indicator considered is the number of national incentives for each vehicle type. There are about 286 different initiatives that target BEV users and 35 that target FCEV users across the different states. On the other hand, there are no existing initiatives for ICEVs. The third indicator at the meso level is the recyclability percentage. In general, an internal combustion engine (ICE) is 76% recyclable, the Li-ion batteries are 95% recyclable, and the fuel cells are 95% recyclable.

4.3. Micro Level Indicators

As mentioned earlier, the micro indicators represent the products and users. One of the most important indicators at this level is the total cost of operation (TCO). The total cost of operation (TCO), presented in Figure 6, consists of six sub-indicators: the capital cost, energy costs, insurance costs, registration and state fees, maintenance and repair costs, and the home charging installation cost if applicable. Capital costs are estimated to be 14,317 USD for an ICEV, 23,805 USD for a BEV, and 20,523 USD for an FCEV. Energy cost is the cost spent by a consumer on refueling during the assessment period. An ICEV owner is expected to spend about 17,694.17 USD on E10 refueling, while a BEV owner will spend 5046.3 USD on electricity, and an FCEV owner will spend 38,695.64 USD on hydrogen. The insurance costs for 10 years are estimated to be 13,968 USD for an ICEV, 21,471 USD for a BEV, and 20,648.40 USD for an FCEV. Registration and state (R and S) fee is paid once during the registration of the vehicle. The average state fees imposed on ICEVs, BEVs, and FCEVs are 655.65 USD, 1370.11 USD, and 1417.13 USD respectively. Maintenance refers to regular services intended to lengthen the vehicle’s lifetime and prevent damage during its operation. These can include scheduled and unscheduled maintenance. In comparison, repair refers to the repair of malfunctioning parts that impede the vehicle’s functionality. The maintenance and repair (M and R) costs 16,597 USD for an ICEV, 11,197 USD for a BEV, and 10,097 USD for an FCEV during their lifetimes. Lastly, the home charging installation applies to BEVs only. It is estimated to cost around 1970 USD. The previously mentioned costs and expenses result in a total cost of operation of 63,286 USD for an ICEV, 64,859 USD for a BEV, and 100,389 USD for an FCEV in 10 years period.

Other micro indicators are the refueling/recharging time, tailpipe emissions, required maintenance frequency, vehicle efficiency, energy source utilization percentage, range on full tank/battery, technology readiness level (TRL) scale, and range anxiety are summarized in

Table 3. Summary of the indicators used to assess the circularity of ICEVs, BEVs, and FCEVs as obtained in Section 3.1, Section 3.2 and Section 3.3.

Level	Indicator		Unit	ICEVs	BEVs	FCEVs
Macro Indicators	1	Energy consumed during the production of fuels	MWh	247.6	89.3	134.5
	2	Water consumed during the production of fuels	m3	124.4	102.5	48.5
	3	Emissions produced during the production of fuels	tonne	11.8	18.0	27.3
	4	Energy consumed during the production of materials involved in the manufacturing of the vehicle	MWh	17.4	15.9	27.1
	5	Water consumed during the production of materials involved in the manufacturing of the vehicle	m3	25.7	22.0	33.5
	6	Emissions produced during the production of materials involved in the manufacturing of the vehicle	tonne	3.7	3.4	5.5
	7	Energy consumed during the production of battery materials	kWh	55.1	17,922.8	1423.1
	8	Water consumed during the production of battery materials	m3	0.2	34.5	1.8
Meso Indicators	10	Number of refueling stations across the U.S.	#	150,000	46,067	48
	11	National incentives	#	0	286	35
	12	Recyclability rate	%	76	95	95
Micro Indicators	13	Total cost of ownership	USD	63,286.0	64,859.0	100,381.0
	13.1	Capital cost	USD	5000.0	20,500.0	30,871.2
	13.2	Energy cost	USD	17,694.2	5046.3	38,695.6
	13.3	Insurance cost	USD	13,968.0	21,471.0	20,648.4
	13.4	Registration and state fees	USD	655.7	1370.1	1417.1
	13.5	Maintenance and repair costs	USD	16,597.0	11,197.0	10,097.0
	13.6	Home charging installation	USD	0	1970.0	0
	14	Vehicle’s lifetime	years	14	14	10.5
	15	Re-Fueling/Charging time	minutes	2.5	155	2.5
	16	Tailpipe emissions	kg Co2	48,036	0	0
	17	Required maintenance frequency	km	12,000	200,000	200,000
	18	Vehicle’s efficiency	%	40	85	85
	19	Energy source utilization percentage	%	77	60	30
	20	Range on a full charge/tank	Km	546.5	314.5	584.2
	21	Technology readiness level	#	9	7	8
	22	Range anxiety	Low Medium High	Low	Medium	High

along with the other level indicators.

4.4. Final Circularity Scores

Based on the CE assessment framework [37], the indicators are grouped and the GRA, TOPSIS, and COPRAS methods are used to obtain the circularity results and rank the three vehicle types. The BEVs ranked first, ICEVs ranked second, and FCEVs ranked last.

Table 4. Circularity scores and rankings obtained using GRA, TOPSIS, and COPRAS methods.

	MCDM Methods Scores			Rankings			Circularity Scores (Average)
	GRA	TOPSIS	COPRAS	GRA	TOPSIS	COPRAS
ICEV	33.90	32.80	31.96	2	3	2	32.9
BEV	34.15	35.95	40.28	1	1	1	36.8
FCEV	31.95	31.26	27.76	3	3	3	30.3

presents the scores and rankings obtained using the three MCDM methods used, and the average relative circularity scores of each vehicle type.

Results showed that BEVs scored the highest in terms of circularity, suggesting that they are the most suitable vehicle type to use on a large scale to facilitate our transition to a CE model. This, however, does not necessarily mean that by replacing the current LDV fleet with BEVs, a carbon-neutral goal would be achieved. The analysis has shown that BEVs produce 64.5% more emissions than ICEVs on the macro level. ICEVs, however, bypass emission production at the micro level due to the additional 48 tonnes of tailpipe emissions produced during the usage stage of the vehicles. More than 70% of the BEV- associated emissions produced on the macro level are caused by the generation of the electricity that is used to operate the vehicle during its lifetime. These are referred to as indirect emissions. While indirect emissions are as significant as direct emissions, they are often ignored when promoting BEVs to the public. Both BEVs and FCEVs are labelled as ZEVs (i.e., zero-emission vehicles), which can be misleading to some extent. For BEVs and FCEVs to be ZEVs, indirect emissions should be completely eliminated.

The energy mix plays a significant role In determining the amounts of indirect emissions. The energy mix used in this analysis is the U.S. energy mix. In the U.S., almost 60% of electricity is generated from fossil fuels, mainly natural gas (66.7%) and coal (33.3%), and the other 40% is generated from clean energy sources, mainly nuclear power (52.6%), wind power (22.9%), hydroelectric power (18.8%), and solar power (5.7%). To further increase the circularity of BEVs, the energy mix that is used to generate electricity can be made more environmentally friendly by increasing the clean energy content of the mix. Figure 7 illustrates the amount of emissions produced by different energy mixes used in the production of the electricity used by a single BEV during its lifetime. It can be noticed that as the share of clean energy sources in the energy mix increases, a noticeable decrease in emissions is observed, reaching almost zero when 100% of the energy mix is clean. Despite the decrease in emissions, water consumption continues to increase. This can be explained by the high ratio of nuclear power in the clean energy sources used in the analysis, which was maintained at 52.6% of the total clean energy share to match the current U.S. energy mix. Water is used in nuclear plants to transport heat from the reactor to the steam turbines and acts as a coolant and a moderator inside the reactor vessel [83]. The water disposed back into bodies of water is usually at a higher temperature, which is a potential cause of thermal pollution. Hence, it is very important to utilize other forms of clean energy along with nuclear power to reduce any form of stress on the environment and achieve higher circularity.

It is also worth noting that energy mixes along with other factors such as fuel economy and fuel-type, play an important role in determining the carbon debt pay-off period of BEVs and FCEVs. Based on the analysis, a BEV and an FCEV produce an additional 9.8 and 17.2 tonnes of CO₂, respectively, when compared to ICEVs at the macro level. As presented in Figure 8, it takes a BEV around 46,951 km or 2 years to pay off its carbon debt, while it takes an FCEV around 82,634 km or 3.6 years to pay off its carbon debt. These results may vary between vehicle types and when other types of energy mixes are used. For example, if the clean energy content is to increase in the energy mix, the carbon debt payback period of BEVs will decrease accordingly.

Several other parameters can also be improved to enhance the circularity of BEVs. For example, the amount of water and energy consumed, and the emissions produced when Li-ion batteries are being produced can be reduced. The assessment showed that Li-ion batteries are responsible for 14.5% and 21.7% of the total energy and water consumed, and 16% of the emissions produced by BEVs on the macro level. To decrease these numbers, retired Li-ion batteries can be reused, remanufactured, repurposed, or recycled. These solutions will have positive environmental, economic, and social impacts. Several resources, such as lithium, nickel, cobalt, and manganese, are used in Li-ion batteries. By implementing the aforementioned solution, we decrease and limit biodiversity loss, soil degradation, and pollution caused by mining activities [84]. It will also prevent conflicts caused by diverting scarce water resources away from local communities toward mining sites [84]. The analysis also highlighted that although the initial cost of a BEV is high, the overall running costs (including the initial costs) of ICEVs and BEVs are similar, with an expected reduction in the capital cost of BEVs as battery technologies advance, making BEVs more favorable in terms of running costs in the coming years. In contrast, FCEVs cost 57% more to run over a period of 10 years. This, along with the lack of hydrogen refueling stations and the substantially larger amounts of emissions that FCEVs cause at the macro level, makes it a nonpractical alternative. In fact, ICEVs are currently more circular than FCEVs, making the latter the least favorable option.

It is evident that the adoption rate of BEVs will be on the rise in the upcoming years. As this study has shown, BEVs are currently considered the most sustainable vehicle option. This, along with the development and optimization of charging infrastructure [85,86], improvement of electrical grid infrastructure [87], and increased public awareness of environmental issues will further facilitate the adoption rate of BEVs [88].

5. Conclusions

The results of this work suggest that in order to reach global goals of sustainable development in the LDV transportation sector, the current LDV fleet should consist mostly of BEVs. In addition, it is crucial to increase the content of clean energy sources in the energy mix while maintaining low water consumption by diversifying the clean energy sources. As well, all Li-ion batteries need to be recycled in a sustainable manner, or at least reused, to minimize and preferably eliminate the mining of further resources. The results also concluded that in their current state, FCEVs are considered neither a functional nor a sustainable alternative to ICEVs. The main findings of the paper are summarized below:

–

Results show that BEVs are the most suitable alternative to ICEVs to promote the transition to circular economies and to accelerate sustainable development.

–

The upstream processes involved in the production of BEVs and FCEVs fuels, produces substantial amounts of emissions.

–

To enhance the circularity of electricity production, clean energy share should increase in the energy mix used. However, by increasing the clean energy share in the energy mix, water consumption also increases. This is mainly due to the increase in the nuclear energy share.

–

Different energy mixes should be further investigated to obtain an optimum clean energy mix that will not use substantial amounts of resources.

–

Similarly, to increase the circularity of hydrogen production, natural gas should be substituted by water as the source of hydrogen. However, the process of electrolysis that produces hydrogen from water uses a considerable amount of electricity. Thus, electricity should be generated from clean energy sources only to sustain circularity.

–

The average costs of purchasing a BEV or FCEV are higher than that of an ICEV. However, by adding the operational costs of the three vehicles throughout the assessment period of 10 years, a BEV will only cost an additional 1573 USD. On the other hand, an FCEV will cost an additional 37,103 USD. These cost differences decrease as technologies improve.

–

BEVs enabling infrastructure is improving, making it socially more acceptable and convenient. Yet, FCEVs are not a convenient option at the time being, given the very limited available hydrogen refueling stations.

–

95% of BEVs and FCEVs main components can be recycled making their end-of-life handling better than that of ICEVs.

–

Overall, BEVs are considered more circular than both ICEVs and FCEVs. However, several improvements are yet to be made to achieve the global environmental targets of carbon neutrality and sustainable development.