Environmental Impact of Alternative Fuels and Vehicle Technologies: A Life Cycle Assessment Perspective

Abstract

Nowadays a wide range of options of vehicles fuels and technologies are commercially available. Still, the complicated nature of environmental impacts caused by each option makes it a tough decision for the consumer, fleet manager, or policy maker to find the best choice. Even policy makers may run into trouble regarding the relative advantages of cleaner options and their relative effects on fuel and vehicle cycle. In light of these, the present paper is an attempt to evaluate the life cycle environmental impacts of road vehicle fuels and available technologies and compare the cleaner options with each other and the main stream fuel/technologies. A complete fuel life cycle assessment (LCA) on petrol, diesel, compressed natural gas (CNG), electric vehicle (EV), hydrogen fuel cell vehicle (FCV), and biodiesel vehicles was made. Results are shown for climate change, air quality effects and Energy resource depletion impact of the different vehicle technologies. As recommended by the results, none of the options dominated the others regarding all dimensions. Instead of mandating a particular solution, such as electric cars or biofuels, probably successful vehicle and fuel policies include established standards of performance and levies to attenuate emissions and let the market to find the best effective alternative.

Full text

Procedia Environmental Sciences 30 ( 2015 ) 205 – 210
1878-0296 © 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of organizing committee of Environmental Forensics Research Centre, Faculty of Environmental Studies,
Universiti Putra Malaysia.
doi: 10.1016/j.proenv.2015.10.037
Available online at www.sciencedirect.com
ScienceDirect
International Conference on Environmental Forensics 2015 (iENFORCE2015)
Environmental impact of alternative fuels and vehicle technologies:
A Life Cycle Assessment perspective
Mohammad Hossein Mohammadi Ashnania,b,c*, Tahere Miremadia, Anwar Joharib and
Afshin Danekarc
aResearch Centre for Science and Technology Policy and Diplomacy, IROST, Tehran, Iran
bInstitute of Hydrogen Economy, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Malaysia
cDepartment of Environmental Sciences, Faculty of Natural Resources Engineering, University of Tehran, Iran
Abstract
Nowadays a wide range of options of vehicles fuels and technologies are commercially available. Still, the complicated nature of
environmental impacts caused by each option makes it a tough decision for the consumer, fleet manager, or policy maker to find
the best choice. Even policy makers may run into trouble regarding the relative advantages of cleaner options and their relative
effects on fuel and vehicle cycle. In light of these, the present paper is an attempt to evaluate the life cycle environmental impacts
of road vehicle fuels and available technologies and compare the cleaner options with each other and the main stream
fuel/technologies. A complete fuel life cycle assessment (LCA) on petrol, diesel, compressed natural gas (CNG), electric vehicle
(EV), hydrogen fuel cell vehicle (FCV), and biodiesel vehicles was made. Results are shown for climate change, air quality
effects and Energy resource depletion impact of the different vehicle technologies. As recommended by the results, none of the
options dominated the others regarding all dimensions. Instead of mandating a particular solution, such as electric cars or
biofuels, probably successful vehicle and fuel policies include established standards of performance and levies to attenuate
emissions and let the market to find the best effective alternative.
© 2015 The Authors. Published by Elsevier B.V.
Peer-review under responsibility of organizing committee of Environmental Forensics Research Centre, Faculty of
Environmental Studies, Universiti Putra Malaysia.
Keywords: Life cycle assessment; fuels and vehicle options; climate change; energy; air pollution; policy
* Corresponding author. Tel.: -
E-mail address: m_h_ashnani@yahoo.com
© 2015 The Authors. Published by Elsevier B.V This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Peer-review under responsibility of organizing committee of Environmental Forensics Research Centre, Faculty of Environmental Studies,
Universiti Putra Malaysia.

206 Mohammad Hossein Mohammadi Ashnani et al. / Procedia Environmental Sciences 30 ( 2015 ) 205 – 210
1. Introduction
The issue of “sustainability” has never been so important in man’s history; so that it is now important more than
other trends such as quality, speed, and production flexibility which were top priorities in the last 25 years. The
attention drawn to sustainability is mainly rooted in social awareness of necessity of reaching a balance between
human development and conservation of the environment [1]. There are more than enough reasons explaining
initiation of transition from the conventional options on the road transport sector toward new options including
increase of oil price, the climate change problems, the increasing restrictions on pollutant emissions, the high
dependence of road transport sector on oil, economic impact, and geological concerns, etc.
Global stability convincingly has never been threatened so persistently like it is by climate change and probably
the threat is the most critical challenge in the way of humanity in this century [2, 3]. To realize what was agreed by
the participating governments at Cancun 2010 [4], which was to limit the rise in global average temperature to less
than 2°C above pre-industrial level, the total carbon dioxide volume that is allowed to be emitted until 2050 should
be around 565-886 billion tonnes (Gt) [5, 6] so that two third of this fuel must stay in the ground to meet the goals of
Cancun summit.
Additionally, fossil fuels are finite and soon there would be no more fossil fuel. Thereby, fossil fuel use should be
“sustainable” as without it, our future generations’ development might be constrained. That is, one of the main vital
challenges to the mankind is the fast decrease of organic fuel resources extracted from entrails of the earth and also
increase of consumption rate of the resources [7]. Increase of world energy consumption led to 12730.4 million
tonnes oil equivalent a year by 2.3% in 2013, which means an acceleration over 2012 (+1.8%) [8]. At currently state
of the curves of energy consumption and production of energy from oil, reserve depletion would between 34-43
years, and this figure for gas is 37-70 [6, 9-11] and for uranium 235 in the beginning of 50-ies of the current century
[7]. To put it another way, the production-consumption balance of energy based on oil, gas, and uranium-235
sources will change from positive to negative [7]. In spite of commonly heard claim that there is enough coal for
hundreds of years (reserve depletion time 106-200) [6, 9-11], in absence of oil and gas, the coal deposits would be
enough until 2088 [12].
The key drivers behind the growth of energy demand are population growth and increase in income per person.
Estimates say that world population reaches 8.7 billion by 2035, which is 1.6 billion increase in energy consumers.
Add to this that GDP per person in 2035 is expected to grow by 75%, which is an increase in productivity equal with
three-quarters of global GDP growth [13]. Thereby, the issue of energy security will challenge us at national and
international levels while a sustainable replacement for fuels and nuclear power is not found [7].
In general, the transport section produces almost a quarter of global energy-rated greenhouse gas emissions. Road
transportation covers the largest portion (more than 70%), followed by marine (15%), and aviation (10%). The main
portion of road transportation emissions comes from light-duty vehicles and trucks [14-16] (Fig. 1).
Fig. 1. The transport sector as a major contributor to global energy-related CO2 emissions
One main cause of air pollution is transport sector [17-19] so that as recommended by estimates, it caused 3.7
million premature death all around the world in 2012. These deaths were caused by exposure to small particles of 10
microns or less in diameter (PM10), which induces cardiovascular and respiratory disease and cancer. About 88% of
these mortalities take place in low-and middle-income countries. The annual cost of air pollution to the developed
countries including India and China is around US$3.5 trillion per year in lives lost and ill health [20, 21].

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Mohammad Hossein Mohammadi Ashnani et al. / Procedia Environmental Sciences 30 ( 2015 ) 205 – 210
Given this introduction, it is essential to make a shift towards a more sustainable transport system by cutting
fossil fuels consumption through finding new vehicle technologies and alternative fuels. The Life Cycle Assessment
(LCA) methodology is of the capacity of being a key management tool to help decision makers to achieve a holistic
insight into the entire system associated with single product/service to be introduced. Still, what we usually
encountered with in such situations is that the “cleaner energy” will always take place in the future, and thereby,
there is always some extent of subjectivity in the analysis, even in the inventory analysis phase of the LCA method,
which is supposedly highly quantitative and objective. This study is aimed at assessing the life cycle environmental
impact of road vehicle fuels and technologies and comparing the cleaner alternatives with each other and also the
mainstream of vehicle fuels/technologies for better transport policies in the future.
2. Methods
Different vehicle technologies are usually assessed from different points in their life cycle using life cycle
assessment (LCA) method. The method is a “cradle-to-grave” approach of evaluating systems or technologies
through compiling a stock of relevant inputs and outputs, assessing the potential environmental impacts associated
with known inputs and outputs, and analyzing the results of inventory and impact phases to achieve better informed
decisions [22].The main areas of using LCAs is to assess and compare the general environmental load from a variety
of competing technologies. The advantage of the approach lies with the fact that, as the analyses is made on a life
cycle basis, materials, products or processes with different resource use and emission pathways can be compared.
The present study is a streamlined LCA using midpoint model. All the data used in this assessment were collected
based on three set questionnaire and the most recent literature reviews and statistics [22-27].
According to reports by International Organization for Standardization (ISO) and the Society for Environmental
Toxicology and Chemistry (SETAC), the LCA methodology is comprised of four interrelated stages: Goal and
Scope Definition, Life Cycle Inventory Analysis (LCI), Life Cycle Impact Assessment (LCIA) and Interpretation
[28-30]. There are two significantly important aspects when it comes to analyzing a new power train/fuel
combination in the automotive sector, which are energy efficiency and pollutant emissions. A standard LCA
estimates energy and material flows pertinent to all stages of product’s life time (Cradle-to-grave). Additionally,
there are two distinguishable life cycles in the automotive life cycle analysis: the vehicle life cycle and fuel life
cycle. The former refers to material production, vehicle assembly, distribution, and disposal. The latter, which is
also known as well-to-wheels analysis (from energy feedstock recovery, “well”, to energy delivering to the vehicle,
“wheels”), can be divided into two key stages: the well-to-tank (energy consumption and emissions to extract raw
materials, to transport them, to produce the desired fuel, to distribute the fuel to consumers, and so on); and tank-to-
wheels (energy consumption and emissions caused by using the fuel by vehicle) [22, 31, 32].
What is provided by the goal and scope of definition of an LCA is a description of the product system in terms of
the system limitations and a functional unit. The functional unit gives us a way to compare and analyze different
goods or services. Within the scope of this paper, it is defined as driving 1km. The vehicles focused in this study are
passenger car weigh 1100-1400 kg. A brief description of the vehicle/fuel life cycle is pictured in Fig. 2.
Fig. 2. Automobile/fuel life c ycle
The life cycle inventory (LCI) analysis takes into account all required resources and all emissions released by the
specific system under investigation and relates them to the defined functional unit [29]. The aim of life cycle impact
assessment (LCIA) is to interpret the LCI data through three steps: characterization, normalization, and weighting.
The impacts that were taken into account are energy (KJ) and greenhouse gases (GHG) and particulate matter (PM).
Primary energy
Raw Materials
Vehicle
Vehicle Use
Vehicle End-of-life
Waste Management
Landfill
Scrap / Recycle
Fuel Production
Fuel Distribution
Maintena
Fixed

208 Mohammad Hossein Mohammadi Ashnani et al. / Procedia Environmental Sciences 30 ( 2015 ) 205 – 210
The three functional metrics are used to determine the anticipated categorical impact of the different vehicles on
resource depletion (energy efficiency), climate change, and air quality respectively. By fuel we refer to gasoline,
diesel, natural gas, biodiesel, electricity, and hydrogen. To compute global warming potential (GWP), the CO2
equivalent factors from the intergovernmental panel on climate change (IPCC) was used [33]. Based on this
procedure, each power train/fuel combination can be used to compare a uniform energy- environmental basis.
3. Results and Discussion
To achieve the full life cycle results for the selected technologies, all results of WTW and vehicle production
stages were used. LCA analysis results are pictured in Fig. 3-5; where Petr stands for gasoline, Dies stands for
diesel, BioD stands for biodiesel, CNG stands for compressed natural gas, EV stands for electric vehicle, and FCV
stands for hydrogen fuel cell vehicle. The findings must be taken into account in the context of the limitations of the
high level, streamlines nature of the study. In addition, the existence of different parameters led us to spread LCA
results, which is shown in the results with error bars.
The best energy life cycle value is filled by FCV (power train) H2 (fuel) combination (Fig. 3). Taking into
account the simple configuration and light weight of conventional vehicle (CV) and the lowest energy use during the
vehicle production stage, CV does result in good performance compared with advance vehicles.
Fig. 3. Energy resource depletion of different fuel/vehicle technologies
Very high values are obtained with Bio-diesel in fact; it suffers from a very high WTWe. From energy viewpoint,
thereby, biofuel options still have to compete with traditional fuels and natural gas. Given their high impact on
WTW and vehicle production stages because of combined effect of 1- the high share of fossil in the mix; and 2- the
low efficiency of conversion technologies in electricity, EV’s performance is not satisfactory. The TTWe. could be
better, but it is constrained by the heavy weight of the battery.
Comparing different car technologies indicates that the climate impact is considerably under the effect of vehicle
technology, the type of fuel and the feedstock used to generate the fuel (Fig. 4). The best position is filled by the
biofuels given their CO2 credit. Results with FCV are satisfactory, which is comparable with those of EV. The
contribution of the lithium ion battery to the overall impact is significant. The traditional fuels have higher GHG
emission and petrol has the highest GHG emission comparing with other options.
Fig. 4. The effect of various vehicle technologies on climate change
0
1000
2000
3000
4000
5000
6000
Petr Dise CNG BioD EV F CV
Energy KJ / KM
Fuel Cycle Vehicle Cycle
0
50
100
150
200
250
300
350
400
Petr Dise CNG BioD EV FCV
greenhouse gas gr / KM
Fuel Cycle Vehicle Cycle

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Mohammad Hossein Mohammadi Ashnani et al. / Procedia Environmental Sciences 30 ( 2015 ) 205 – 210
As pictured in Fig. 5, electric vehicles with average mix electricity have the highest particular emission on a life
cycle basis. The reason is high level of particulates emitted during electricity generation. In addition, diesel and
biodiesel life cycle emissions are also larger than other cases because of significant particulate emission generated
during vehicle operation.
Fig. 5. Air quality impact of different fuel/vehicle technologies
That is, all other cases are notably similar in life cycle particulate which is mainly because of the majority of life
cycle particulate emission of vehicle manufacture. However, all particulate emissions of the other cases are
generated while fuel production are located far away from most major cities- in some cases, refinery, fuel processing
or vehicle manufacturing plants are located in populated region.
4. Conclusion
The key contribution of LCA methods and studies like the present one is helping decision makers to focus better
on the important attributes and avoid focusing only on one aspect of fuel cycle or propulsion system or at only one
media for environmental burdens. Analysis results regarding both energy efficiency and pollutant emissions lead to
notable conclusions: which solution indicates a clear advantage regarding primary sources exploitation, and which
one permits reducing pollutant substances in the overall fuel cycle. Still, a reliable solution as to energy aspects
might not be as good regarding environmental aspects or vice versa. However, taking into account complicacy of
transportation system, modifications to reduce one problem may lead to exacerbation of others. The results also
illustrated that all the fuel-efficient technologies, mainly biodiesel, may improve the GHG over the lifetime of the
vehicle. On the other hand, conventional biofuels are not free of disadvantages as they are too costly and at the
current state they need considerable quantities of fossil resources. These disadvantages may be decreases by
technological advances, as pictured in the 2030 forecast. Due to considerable efficiencies of fuel cycle, the FCV can
achieve minimum energy consumption – i.e. 20% reduction comparing with CV. LCA analyses results showed that
CNG vehicles provide air quality benefits. The study also indicated necessity to focus more on fuel life cycle taking
into account that its weight comparing with vehicle life cycle.
There are many factors to be concerned with in developing a sustainable transportation system; including the
relative roles of public and private transportation, the types of fuels that is available in log-run, geopolitical issues,
primary sources deletion, GHG and pollutant emissions of the fuel/vehicle usage, the life cycle energy and emission
of the vehicle, available fuel infrastructure, safety, affordability and consumer acceptance of fuels and vehicle and
so on. Probably successful vehicle and fuel policies include established standards of performance and levies to
attenuate emissions. Instead of mandating a particular solution, such as electric cars or biofuel, it is far better to set
overarching policy goals and let the market to find the best cost effective alternative. Effective vehicle emission
performance standards compatible with revenue-neutral fuel fees many can be of great reduction of nations’ annual
emission – and save a considerable sums of fuel reserves and money. Vehicle effectiveness improvement needs
more up-front investment, which results in increase of economic growth and more job opportunities. Additionally,
by cutting fuel usage, the improvements leads to higher national security and results in considerable savings to
consumers. Through this, the consumer will enjoy more sources to purchase other goods and services, which leads
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
Petr Dise CNG BioD EV FCV
particulate matter (PM ) gr/KM
Fuel Cycle Vehicle Cycle

210 Mohammad Hossein Mohammadi Ashnani et al. / Procedia Environmental Sciences 30 ( 2015 ) 205 – 210
to better economic condition. By cutting conventional pollutants, the policies also improve public health. Taking
into account the immense change of social and driver goals and availability of technology in the last 50 years,
greater changes are expected in the next 30-40 years, which makes is hard to say which fuel/technology will be the
winner in 2050 [15, 25].
Acknowledgements
We gratefully acknowledge the support and generosity of Research Center for Science and Technology Policy
and Diplomacy (MAPSED) Foundation, without which the present study could not have been completed. The
authors appreciated the support of Universiti Teknologi Malaysia and Malaysian Min. of Higher Education (GUP
grant VOT No. 07H11).
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