Purpose
A literature review is undertaken to understand how well existing studies of the environmental impacts of hybrid and electric vehicles (EV) address the full life cycle of these technologies. Results of studies are synthesized to compare the global warming potential (GWP) of different EV and internal combustion engine vehicle (ICEV) options. Other impacts are compared; however, data availability limits the extent to which this could be accomplished.

Environmental impacts of hybrid and electric vehicles—a review

As concerns of oil depletion and security of supply remain as severe as ever, and faced with the consequences of climate change due to greenhouse gas emissions, Europe is increasingly looking at alternatives to traditional road transport technologies. Battery Electric Vehicles (BEVs) are seen as a promising technology, which could lead to the decarbonisation of the Light Duty Vehicle fleet and to independence from oil. However it still has to overcome some significant barriers to gain social acceptance and obtain appreciable market penetration. This review evaluates the technological readiness of the different elements of BEV technology and highlights those technological areas where important progress is expected. Techno-economic issues linked with the development of BEVs are investigated. Current BEVs in the market need to be more competitive than other low carbon vehicles, a requirement which stimulates the necessity for new business models. Finally, the all-important role of politics in this development is, also, discussed. As the benefit of BEVs can help countries meet their environmental targets, governments have included them in their roadmaps and have developed incentives to help them penetrate the market.

A review of Battery Electric Vehicle technology and readiness levels

The purpose of this review article is to investigate the usefulness of different types of life cycle assessment (LCA) studies of electrified vehicles to provide robust and relevant stakeholder information. It presents synthesized conclusions based on 79 papers. Another objective is to search for explanations to divergence and “complexity” of results found by other overviewing papers in the research field, and to compile methodological learnings. The hypothesis was that such divergence could be explained by differences in goal and scope definitions of the reviewed LCA studies. The review has set special attention to the goal and scope formulation of all included studies. First, completeness and clarity have been assessed in view of the ISO standard’s (ISO 2006a, b) recommendation for goal definition. Secondly, studies have been categorized based on technical and methodological scope, and searched for coherent conclusions. Comprehensive goal formulation according to the ISO standard (ISO 2006a, b) is absent in most reviewed studies. Few give any account of the time scope, indicating the temporal validity of results and conclusions. Furthermore, most studies focus on today’s electric vehicle technology, which is under strong development. Consequently, there is a lack of future time perspective, e.g., to advances in material processing, manufacturing of parts, and changes in electricity production. Nevertheless, robust assessment conclusions may still be identified. Most obvious is that electricity production is the main cause of environmental impact for externally chargeable vehicles. If, and only if, the charging electricity has very low emissions of fossil carbon, electric vehicles can reach their full potential in mitigating global warming. Consequently, it is surprising that almost no studies make this stipulation a main conclusion and try to convey it as a clear message to relevant stakeholders. Also, obtaining resources can be observed as a key area for future research. In mining, leakage of toxic substances from mine tailings has been highlighted. Efficient recycling, which is often assumed in LCA studies of electrified vehicles, may reduce demand for virgin resources and production energy. However, its realization remains a future challenge. LCA studies with clearly stated purposes and time scope are key to stakeholder lessons and guidance. It is also necessary for quality assurance. LCA practitioners studying hybrid and electric vehicles are strongly recommended to provide comprehensive and clear goal and scope formulation in line with the ISO standard (ISO 2006a, b).

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Environmental impacts of hybrid, plug-in hybrid, and battery electric vehicles—what can we learn from life cycle assessment?

Electric and hybrid vehicles are associated with green technologies and a reduction in greenhouse emissions due to their low emissions of greenhouse gases and fuel-economic benefits over gasoline and diesel vehicles. Recent analyses show nevertheless that electric vehicles contribute to the increase in greenhouse emissions through their excessive need for power sources, particularly in countries with limited availability of renewable energy sources, and result in a net contribution and increase in greenhouse emissions across the European continent. The chemical and electronic components of car batteries and their waste management require also a major investment and development of recycling technologies, to limit the dispersion of electric waste materials in the environment. With an increase in fabrication and consumption of battery technologies and multiplied production of electric vehicles worldwide in recent years, a full review of the cradle-to-grave characteristics of the battery units in electric vehicles and hybrid cars is important. The inherent materials and chemicals for production and the resulting effect on waste-management policies across the European Union are therefore reported here for the scope of updating legislations in context with the rapidly growing sales of electric and hybrid vehicles across the continent. This study provides a cradle-to-grave analysis of the emerging technologies in the transport sector, with an assessment of green chemistries as novel green energy sources for the electric vehicle and microelectronics portable energy landscape. Additionally, this work envisions and surveys the future development of biological systems for energy production, in the view of biobatteries. This work is of critical importance to legislative groups in the European Union for evaluating the life-cycle impact of electric and hybrid vehicle batteries on the environment and for establishing new legislations in context with waste handling of electric and hybrid vehicles and sustain new innovations in the field of sustainable portable energy.

Electric vehicle battery technologies: From present state to future systems

This paper proposes methodologies to estimate the electric energy and power consumption by light-duty plug-in electric vehicles (PEVs). Using the travel patterns of light-duty vehicles in the U.S. obtained from the 2009 National Household Travel Survey, the PEVs' energy and power consumption are estimated for two uncontrolled charging scenarios.

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Electric Energy and Power Consumption by Light-Duty Plug-In Electric Vehicles

In this paper, an environmental comparison of electric, hybrid, LPG and gasoline passenger vehicles is performed through a Life Cycle Assessment (LCA) approach. Thanks to a range-based modeling system, the variations of the weight, the fuel consumption and the emissions within the family car category are considered instead of the average values. Unlike in a classic LCA, the use phase of vehicles has been modeled to cover vehicles with both a short and long lifespan in such way that the number of times a vehicle needs to be produced to cover the comparison basis or functional unit is taken into account. According to the assumptions and the used impact calculation method, the greenhouse effect of the LPG hybrid and battery electric vehicles are respectively 20.27 %, 27.44 % and 78.27% lower than for the gasoline vehicles. The assessment of the impact on human health and the air acidification give the best environmental score to the battery electric vehicle. A sensitivity analysis has allowed the assessment of the correlation between the respiratory effects and the euro emission standards.

Comparative LCA of electric, hybrid, LPG and gasoline cars in Belgian context

In this paper it is examined how environmentally friendly conventional and new vehicle technologies are and how their environmental effects can be compared. An automotive Life Cycle Assessment (LCA) is being performed for small family passenger vehicles in Belgium. Next to the well-to-wheel (WTW) emissions (related to fuel production, distribution and fuel use in the vehicle), the LCA also includes cradle-to-grave emissions (related directly and indirectly to the vehicle production, transportation, maintenance and the end-of-life (EoL) processing of the vehicle). The considered impact categories are: air acidification, eutrophication, human health and greenhouse effect (GHE). Thanks to a range-based modeling system, the variations of the weight of the vehicles, the fuel consumption and the emissions are taken into account. The results show that the battery electric vehicle (BEV) has the best environmental score for all the considered impact categories. Petrol vehicles have the worst impact on the greenhouse effect, but hybridization of the drive train has a positive influence on this impact category. The impact of the hybrid vehicle is considerably lower than of the equivalent petrol vehicle. On the other hand, when assessing the acidification impact, one can notice that the hybrid car has a high impact. Without the recycling of the NiMH battery, the results for the hybrid vehicle would be even higher than for the equivalent petrol vehicle. This is due to the production of the nickel contained in the NiMH battery. Vehicles running on diesel have the highest impact on eutrophication. The tank-to-wheel (TTW) part contributes the most to the overall impact on eutrophication, as a result of the NO X emissions. The evaluation of the impact on human health shows that the petrol vehicle has the highest impact, due to the high NO X , particulate matter (PM) and SO X (WTT) emissions.

Nele Sergeant

Papers

Comparative LCA of electric, hybrid, LPG and gasoline cars in Belgian context

Life Cycle Assessment of conventional and alternative small passenger vehicles in Belgium

Clean Vehicle Research: LCA and Policy Measures (CLEVER)

How green is the car purchase decision? A Review

Comparative LCA of Electric, Hybrid, LPG and Gasoline family cars in a Belgian context