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Sam McWilliam
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Friday, August 29, 2008
Fuel Cell vs Plug in Electric Vehicles
A Cost Comparison of Fuel-Cell and Battery Electric Vehicles
Stephen Eaves*, James Eaves
Eaves Devices, Charlestown, RI, Arizona State University-East, Mesa, AZ
Abstract
This paper compares the manufacturing and refueling costs of a Fuel-Cell Vehicle (FCV)
and a Battery Electric Vehicle (BEV) using an automobile model reflecting the largest
segment of light-duty vehicles. We use results from widely-cited government studies to
compare the manufacturing and refueling costs of a BEV and a FCV capable of delivering
135 horsepower and driving approximately 300 miles. Our results show that a BEV
performs far more favorably in terms of cost, energy efficiency, weight, and volume. The
differences are particularly dramatic when we assume that energy is derived from
renewable resources.
Keywords: Battery-Electric Vehicle; Fuel-Cell Vehicle; Well-to-Wheel; Energy Pathway
* Corresponding author. Tel.: 401-315-0547; E-mail: stepheneaves@eavesdevices.com
1. Introduction
Both the federal and state governments have enacted legislation designed to promote
the eventual widespread adoption of zero-emissions vehicles. For instance, California
enacted the Zero-Emissions-Vehicle (ZEV) program mandating automakers to claim
ZEV credits for a small percentage of total vehicle sales starting in 2003.
Further, the last version of the 2003 energy bill included over a billion dollars
in incentives for automakers to develop technology related to Fuel-Cell Vehicles.
Currently, the Fuel-Cell Vehicle (FCV) and the Battery Electric Vehicle (BEV)
are the only potential ZEV replacements of the internal combustion engine,
however, no studies have directly compared the two technologies in terms of performance
and cost when considering the most recent advances in battery and fuel-cell technology.
Below, we compare BEV and FCV technologies based on a vehicle model that is capable
of delivering 100 kW of peak power, and 60 kWh total energy to the wheels.1 This translates
into a vehicle that is capable of delivering 135 horsepower and driving
approximately 300 miles. The vehicle characteristics are comparable to a small
to midsize car, such as a Honda Civic, representing the largest segment of the
light-duty vehicle class [1]. We first compare the relative efficiency of the vehicles
well-to-wheel pathways. This allows us to calculate the amount of energy a power plant
must produce in order to deliver a unit of energy to the wheels of a FCV and a
BEV. Next, we compute the volume, weight, and refueling costs associated
with each vehicle. We make these calculations first assuming that the
hydrogen for the FCVs and the electricity for the BEVs are generated using nonfossil
fuel sources. After, we relax this assumption to consider the case where
hydrogen is reformed from natural gas and the electricity for BEVs is generated
using a mix of fossil fuel and non-fossil fuel sources, such as wind and
hydroelectric, as is the norm today.
2. Analysis and Discussion
2.1. Energy Efficiency Comparison assuming energy is derived from renewable resources
A vehicle?s well-to-wheel pathway is the pathway between the original source
of energy (e.g. a wind farm) and the wheels of the car. The pathway?s
components are the energy conversion, distribution, and storage stages required
to transport and convert the energy that eventually moves the automobile. Thus,
analyzing the efficiency of each vehicle?s well-to-wheel pathway allows us to
determine the total amount of energy required to move each vehicle.
Fig. 1 and Fig. 2 illustrate the pathways for BEVs and FCVs, respectively. The first
stage of both pathways is the generation of electricity. Since presumably we are
concerned with the long-run development of a sustainable transportation infrastructure,
we first assume that the electricity is generated by a non-fossil fuel resource
like hydroelectric, solar, wind, geothermal, or a combination. All of
these sources are used to generate energy in the form of electricity. The only
established method to convert electricity to hydrogen is through a process known
as electrolysis, which electrically separates water into its components of
hydrogen and oxygen.
For BEVs, the electricity is delivered over power lines to a battery charger.
The battery charger then charges a Lithium-ion battery that stores the energy
on-board the vehicle to power the vehicle?s drivetrain. In addition to one
storage and two distribution stages, the BEV pathway consists of two conversion
stages (the conversion of, say, wind to electricity in stage 1 and the conversion
of electricity to mechanical energy in stage 2). The figure shows that the entire
pathway is 77% efficient; approximately 79 kWh of energy must be generated in
order to deliver the necessary 60 kWh of electricity to the wheels of the car.
The FCV?s well-to-wheel pathway, illustrated in Fig. 2, is believed by experts
to be the most likely scenario, with some exceptions that are addressed below [2].
In this case, the energy from the electric plant is used for the electrolysis process
that separates hydrogen gas from water. The hydrogen gas is then compressed
and distributed to fueling stations where it can be pumped into and stored aboard
individual fuel-cell vehicles. The onboard hydrogen gas is then combined
with oxygen from the atmosphere to produce the electricity that powers the
vehicle?s drivetrain.
In addition to one distribution and one storage stage, the FCV pathway consists
of four conversion stages (the conversion of, say, wind to electricity in stage 1, the
conversion of electricity to hydrogen in stage 2, the conversion of hydrogen back
to electricity in stage 3, and finally, the conversion of electricity to mechanical
energy in stage 4). Due largely to the fact that there are two additional
conversion stages relative to the BEV and the fact that the onboard conversion
stage is only 54% efficient, the FCV pathway is only approximately 30%
efficient.3 The result is that the pathway requires the production of 202 kWh of
electricity at the plant, to deliver the necessary 60 kWh to the vehicle, or 2.6
times the requirements of the BEV pathway [3]. Obviously, this means that
there would need to be 2.6 times as many wind farms or solar panels to power the
FCVs versus the BEVs. Arguably, a more efficient FCV pathway would be based on-board
fossil fuel reforming or liquid hydrogen storage. However, attempts at these
alternative methods have proven uncompetitive compared to a system based on compressed
hydrogen gas. As a consequence, the pathway illustrated in Fig. 2 is considered by the
DOE and industrial experts to be the most feasible
[2]. However, contrary to our present assumption, the DOE?s support for the
distribution pipeline of Fig. 2 is based on the assumption of initially using fossil
fuels as the source of hydrogen. In the case of renewable energy, it would be
more cost effective to transport the electricity over power lines and perform
the electrolysis at local ?gas stations?, thus eliminating the need for the
expensive and less efficient hydrogen pipeline [4]. Elimination of the hydrogen
pipeline stage significantly increases the overall efficiency of the
pathway, however, 188 kWh is still necessary to deliver 60 kWh to the
FCV?s wheels, or 2.4 times the energy required to power a BEV.
The results of the non-fossil fuel analysis are impacted by the fact that we
do not consider the cost of constructing and maintaining a hydrogen
infrastructure. A renewable hydrogen infrastructure would consist of a network
of electrolysis plants, supported by an intra-national pipeline, which, in turn,
would supply a myriad of hydrogen refueling stations. The cost of hydrogen
production from electrolysis is already well characterized from existing
installations, but accurately projecting the downstream costs of a massive
transportation and distribution infrastructure is much more difficult.
The practical implication of only considering the production costs is that
our estimate of the FCV?s refueling cost is lower than it would be if we
considered infrastructure costs. For instance, the cost of building the
hydrogen refueling stations alone is estimated between $100 billion and $600
billion.[5] The U.S. Department of Energy estimates the costs of the
hydrogen trunk pipelines and distribution lines to be $1.4 million and $0.6 million
per mile, respectively[6]. A BEV infrastructure would be largely based on
the current power grid, making its construction vastly less costly.2
The inefficiency of the FCV pathway combined with the high capital and
maintenance costs of the distribution system results in significant differences in
the refueling cost between a FCV and BEV, particularly if the source is
5 renewable. For example, Pedro and Putsche [7] estimate that using wind
energy, hydrogen production costs alone will amount to $20.76 per tank to drive
our FCV 300 miles compared to $4.28 per tank (or per charge) for the BEV.4
2.2. Comparison of Weight, Volume and Cost Maintaining the same performance
assumptions, we next compare the projected relative weight, volume, and
unit costs of each vehicles propulsion system. The results are reported in Table
1 and Table 2. When interpreting the tables it is important to note that the
limiting factor in FCV performance is the amount of power that can be delivered,
which affects vehicle acceleration and hill climbing. For BEVs, the limiting factor
is the amount of energy that can be delivered, which affects total vehicle
range. This means that the scaling factors for weight, volume, and cost for
the FCV are based on how many Watts (of power) that can be delivered per unit
of weight, volume, or cost. For the BEV it is the amount of Watt·hours (of
energy) that can be delivered per unit of weight, volume, or cost.
Table 1
Estimated weight, on-board space, and mass-production cost requirements of the FCV
propulsion system.
Component Weight Volume Cost Reference
Fuel-Cell 617 kg 1182 liters $23,033 ADL(2001)
3.2 kg storage tank 51 kg 215 liters $2,288 Padro and Putsch(1999)
Drivetrain 53 kg 68 liters $3,826 AC Propulsion,
Inc.(2001),
Total 721 kg 1465 liters $29,147 SolectriaCorp (2001)
Table 2
Estimated weight, on-board space, and mass-production cost requirements of a BEV
propulsion systems
Component Weight Volume Cost Reference
Li-ion Battery 451 kg 401 liters $16,125 Gaines and Cuenca(2000)
Drivetrain 53 kg 68 liters $3,826 Cuenca and Gains
Total 504 kg 469 liters $19,951
2.3. Weight Comparison
According to the DOE report on the status of fuel-cells conducted by Arthur
D. Little [8], a modern fuel cell is presently capable of delivering 182 Watts
of power per kg of fuel-cell. Including the required FCV drivetrain components
and their losses [9,10] and the weight of the storage tank5, a fuel-cell propulsion
system capable of meeting our performance constraint must weigh
approximately 721 kg. According to the National Renewable Energy Laboratory
(NREL) working group report on advanced battery readiness [11], a
Lithium-ion battery is capable of delivering 143 Watts·hours of energy per
kg of battery. Considering an equivalent drivetrain to the one assumed for the
FCV, the battery system must weigh 504 kg to satisfy our performance constraint.6
2.4. Volume Comparison
The Arthur D. Little study reports that the fuel-cell delivers 95 Watts per
liter of fuel-cell, which combined with the volume of the hydrogen storage tank
[12] and the volume of the electric drivetrain components produces a total
volume of 1465 liters.7 A Lithium-ion battery delivers 161 Watt·hours per liter
of battery.8 When combined with the electric drivetrain volume, this results in
a total volume of 469 liters. 2.5. Cost Comparison Finally, The Arthur D. Little
study reports a cost of $205 per kW for a 100kW fuel-cell.9 Adding to this the cost
of the electric motor, control electronics and hydrogen-storage tank implies that
the total cost of $29,147 for the fuel-cell propulsion system(The electric drivetrain
components are $3,826 for the BEV and FCV.) [13]. For the BEV, the cost of a
Lithium-ion battery is estimated to be $250/kWh [14]. Considering the electric
drivetrain, this implies a total cost of $19,951 for the BEV?s propulsion system.
2.6. Energy Efficiency Comparison assuming energy is derived from Fossil Fuels
Most experts are imagining that for many years to come, fossil fuels will be
the main source of the hydrogen or the electricity that powers zero emission
vehicles. In light of this, one should consider the near term case where the
electricity for BEVs is generated using a mix of fossil fuel and non-fossil fuel
sources and the FCV?s hydrogen is reformed from natural gas, as is the norm today.
A 2001 study conducted for the California Air Resources Board found
that when electricity for BEVs is generated using a mix of fossil fuel and
non-fossil fuel and hydrogen is created from natural gas, a BEV pathway is
about 8% more efficient than a FCV pathway. The study also concluded that
the BEV pathway would generate lower greenhouse gas emissions. Although the
efficiency comparison of the two vehicles is much closer than for the non-fossil fuel
case, if the substantial cost of building and maintaining the hydrogen
infrastructure necessary to support the FCV is considered, then the BEV would
clearly be more attractive than the FCV. Further, if renewable energy sources will
eventually replace fossil fuels, then the hydrogen pipeline would at best be
inefficient, and at worst be obsolete. This is because hydrogen producers
would find it more economical to make hydrogen locally by using renewable
electricity to hydrolyze water, rather than purchasing hydrogen transported via
pipeline. Since the nation?s electricity is already generated using an array of fossil
and non-fossil fuel resources, the optimal design of the BEV infrastructure would
not change in the conversion to a nonfossil fuel economy. Lastly, when the non-fossil
fuel assumption is relaxed, the refueling costof a BEV is still far less than that
of the FCV. Pedro and Putsch estimate the retail cost of hydrogen from fossil fuel to
be $2.42 per kg [7]. Given the 3.2 kg of hydrogen necessary to meet our rangeperformance
constraint, this results in a fill-up cost of $7.77 for the FCV.
Accounting for efficiency losses between a BEV?s battery and its wheels,
64.5kWh of energy must be delivered to the BEV battery to assure that 60 kWh is
delivered to its wheels. Considering a 0.89 charger efficiency and a 0.94 battery
efficiency, this implies that 77 kWh of energy must be purchased from the utility
company. Since BEVs will typically be charged at night, an off-peak cost of
$0.06/kWh is applied for the electricity generated from a mix of fossil and nonfossil
fuels. This implies a ?fill-up? cost of $4.63 for the BEV, which is about
40% lower than that of the FCV.
3. Conclusion
We use widely-cited government studies to directly compare the costs
associated with producing and refueling FCVs and BEVs. The analysis is based
on an automobile model (similar to a Honda Civic) that is representative of the
largest segment of the automobile market. A comparison is important since
the government and industry are devoting increasing amounts of resources
to the goal of developing a marketable ZEV and the BEV and the FCV are
currently the only feasible alternatives. We find that government studies
indicate that it would be far cheaper, in terms of production and refueling costs,
to develop a BEV, even if we do not consider the substantial cost of building
and maintaining the hydrogen infrastructure on which the FCV would
depend. Specifically, the results show that in an economy based on renewable
energy, the FCV requires production of between 2.4 and 2.6 times more energy
than a comparable BEV. The FCV propulsion system weighs 43% more,
consumes nearly three-times more space onboard the vehicle for the same power
output, and costs approximately 46% more than the BEV system. Further, the
refueling cost of a FCV is nearly threetimes greater. Finally, when we relax the
renewable energy assumption, the BEV is still more efficient, cleaner, and vastly
less expensive in terms of manufacturing, refueling, and infrastructure investment.
REFERENCES
1 U.S. Environmental Protection Agency, Light-Duty Automotive Technology and Fuel
Economy Trends 1975-2001, 2001.
2 Northeast Advanced Vehicle Consortium (under contract to Defense Advanced Research
Projects Agency), Interviews with 44 Global Experts on the Future of Transportation and
Fuel Cell Infrastructure and a Fuel Cell Primer, Agreement No. NAVC1099-PG030044,
2000.
3 General Motors, Argonne National Laboratory, BPAmoco, Exxon Mobile, and Shell,
Well-to-Wheels Energy use and Greenhouse Gas Emissions of Advanced Fuel/Vehicle
Systems, 2001.
4 CA Energy Commission and the Air Resource Board, A Fuel Cycle Energy Conversion
Efficiency Analysis, 2000.
5 CA Energy Commission and the Air Resource Board, A Fuel Cycle Energy Conversion
Efficiency Analysis, 2000.
6 U.S. Department of Energy, Annual Progress Report, 2003.
7 Padro, C., V. Putsche, Survey of Economics of Hydrogen Technologies, National
Renewable Energy Laboratory Study NREL/TP-570-27079, 1999.
8 Arthur D. Little, Inc. report to Department of Energy, Cost Analysis of Fuel Cell System
for Transportation, Ref. No. 49739, SFAA No. DESC02-98EE50526, 2001.
9 AC Propulsion Inc., AC150 GEN-2 EV Power System Specification Document, 2001.
10 Solectria Corp., DMC0645 AC Motor Controller Specification, 2001.
11 National Renewable Energy Laboratory, Advanced Battery Readiness Ad Hoc Working
Group Meeting Report 2000.
12 Padro, C., V. Putsche, Survey of Economics of Hydrogen Technologies, National
Renewable Energy Laboratory Study NREL/TP-570-27079, 1999.
13 Cuenca, R., L. Gaines, A. V., Evaluation of Electric Vehicle Production and Operating
Costs, Center for Transportation Research, Argonne National Laboratory, 1999.
14 Gaines, L., R. Cuenca, Costs of Lithium Ion Batteries, Center for Transportation
Research, Argonne National Laboratory, 2000.
Copyright 2008. Sam McWilliam. All rights reserved.
Stephen Eaves*, James Eaves
Eaves Devices, Charlestown, RI, Arizona State University-East, Mesa, AZ
Abstract
This paper compares the manufacturing and refueling costs of a Fuel-Cell Vehicle (FCV)
and a Battery Electric Vehicle (BEV) using an automobile model reflecting the largest
segment of light-duty vehicles. We use results from widely-cited government studies to
compare the manufacturing and refueling costs of a BEV and a FCV capable of delivering
135 horsepower and driving approximately 300 miles. Our results show that a BEV
performs far more favorably in terms of cost, energy efficiency, weight, and volume. The
differences are particularly dramatic when we assume that energy is derived from
renewable resources.
Keywords: Battery-Electric Vehicle; Fuel-Cell Vehicle; Well-to-Wheel; Energy Pathway
* Corresponding author. Tel.: 401-315-0547; E-mail: stepheneaves@eavesdevices.com
1. Introduction
Both the federal and state governments have enacted legislation designed to promote
the eventual widespread adoption of zero-emissions vehicles. For instance, California
enacted the Zero-Emissions-Vehicle (ZEV) program mandating automakers to claim
ZEV credits for a small percentage of total vehicle sales starting in 2003.
Further, the last version of the 2003 energy bill included over a billion dollars
in incentives for automakers to develop technology related to Fuel-Cell Vehicles.
Currently, the Fuel-Cell Vehicle (FCV) and the Battery Electric Vehicle (BEV)
are the only potential ZEV replacements of the internal combustion engine,
however, no studies have directly compared the two technologies in terms of performance
and cost when considering the most recent advances in battery and fuel-cell technology.
Below, we compare BEV and FCV technologies based on a vehicle model that is capable
of delivering 100 kW of peak power, and 60 kWh total energy to the wheels.1 This translates
into a vehicle that is capable of delivering 135 horsepower and driving
approximately 300 miles. The vehicle characteristics are comparable to a small
to midsize car, such as a Honda Civic, representing the largest segment of the
light-duty vehicle class [1]. We first compare the relative efficiency of the vehicles
well-to-wheel pathways. This allows us to calculate the amount of energy a power plant
must produce in order to deliver a unit of energy to the wheels of a FCV and a
BEV. Next, we compute the volume, weight, and refueling costs associated
with each vehicle. We make these calculations first assuming that the
hydrogen for the FCVs and the electricity for the BEVs are generated using nonfossil
fuel sources. After, we relax this assumption to consider the case where
hydrogen is reformed from natural gas and the electricity for BEVs is generated
using a mix of fossil fuel and non-fossil fuel sources, such as wind and
hydroelectric, as is the norm today.
2. Analysis and Discussion
2.1. Energy Efficiency Comparison assuming energy is derived from renewable resources
A vehicle?s well-to-wheel pathway is the pathway between the original source
of energy (e.g. a wind farm) and the wheels of the car. The pathway?s
components are the energy conversion, distribution, and storage stages required
to transport and convert the energy that eventually moves the automobile. Thus,
analyzing the efficiency of each vehicle?s well-to-wheel pathway allows us to
determine the total amount of energy required to move each vehicle.
Fig. 1 and Fig. 2 illustrate the pathways for BEVs and FCVs, respectively. The first
stage of both pathways is the generation of electricity. Since presumably we are
concerned with the long-run development of a sustainable transportation infrastructure,
we first assume that the electricity is generated by a non-fossil fuel resource
like hydroelectric, solar, wind, geothermal, or a combination. All of
these sources are used to generate energy in the form of electricity. The only
established method to convert electricity to hydrogen is through a process known
as electrolysis, which electrically separates water into its components of
hydrogen and oxygen.
For BEVs, the electricity is delivered over power lines to a battery charger.
The battery charger then charges a Lithium-ion battery that stores the energy
on-board the vehicle to power the vehicle?s drivetrain. In addition to one
storage and two distribution stages, the BEV pathway consists of two conversion
stages (the conversion of, say, wind to electricity in stage 1 and the conversion
of electricity to mechanical energy in stage 2). The figure shows that the entire
pathway is 77% efficient; approximately 79 kWh of energy must be generated in
order to deliver the necessary 60 kWh of electricity to the wheels of the car.
The FCV?s well-to-wheel pathway, illustrated in Fig. 2, is believed by experts
to be the most likely scenario, with some exceptions that are addressed below [2].
In this case, the energy from the electric plant is used for the electrolysis process
that separates hydrogen gas from water. The hydrogen gas is then compressed
and distributed to fueling stations where it can be pumped into and stored aboard
individual fuel-cell vehicles. The onboard hydrogen gas is then combined
with oxygen from the atmosphere to produce the electricity that powers the
vehicle?s drivetrain.
In addition to one distribution and one storage stage, the FCV pathway consists
of four conversion stages (the conversion of, say, wind to electricity in stage 1, the
conversion of electricity to hydrogen in stage 2, the conversion of hydrogen back
to electricity in stage 3, and finally, the conversion of electricity to mechanical
energy in stage 4). Due largely to the fact that there are two additional
conversion stages relative to the BEV and the fact that the onboard conversion
stage is only 54% efficient, the FCV pathway is only approximately 30%
efficient.3 The result is that the pathway requires the production of 202 kWh of
electricity at the plant, to deliver the necessary 60 kWh to the vehicle, or 2.6
times the requirements of the BEV pathway [3]. Obviously, this means that
there would need to be 2.6 times as many wind farms or solar panels to power the
FCVs versus the BEVs. Arguably, a more efficient FCV pathway would be based on-board
fossil fuel reforming or liquid hydrogen storage. However, attempts at these
alternative methods have proven uncompetitive compared to a system based on compressed
hydrogen gas. As a consequence, the pathway illustrated in Fig. 2 is considered by the
DOE and industrial experts to be the most feasible
[2]. However, contrary to our present assumption, the DOE?s support for the
distribution pipeline of Fig. 2 is based on the assumption of initially using fossil
fuels as the source of hydrogen. In the case of renewable energy, it would be
more cost effective to transport the electricity over power lines and perform
the electrolysis at local ?gas stations?, thus eliminating the need for the
expensive and less efficient hydrogen pipeline [4]. Elimination of the hydrogen
pipeline stage significantly increases the overall efficiency of the
pathway, however, 188 kWh is still necessary to deliver 60 kWh to the
FCV?s wheels, or 2.4 times the energy required to power a BEV.
The results of the non-fossil fuel analysis are impacted by the fact that we
do not consider the cost of constructing and maintaining a hydrogen
infrastructure. A renewable hydrogen infrastructure would consist of a network
of electrolysis plants, supported by an intra-national pipeline, which, in turn,
would supply a myriad of hydrogen refueling stations. The cost of hydrogen
production from electrolysis is already well characterized from existing
installations, but accurately projecting the downstream costs of a massive
transportation and distribution infrastructure is much more difficult.
The practical implication of only considering the production costs is that
our estimate of the FCV?s refueling cost is lower than it would be if we
considered infrastructure costs. For instance, the cost of building the
hydrogen refueling stations alone is estimated between $100 billion and $600
billion.[5] The U.S. Department of Energy estimates the costs of the
hydrogen trunk pipelines and distribution lines to be $1.4 million and $0.6 million
per mile, respectively[6]. A BEV infrastructure would be largely based on
the current power grid, making its construction vastly less costly.2
The inefficiency of the FCV pathway combined with the high capital and
maintenance costs of the distribution system results in significant differences in
the refueling cost between a FCV and BEV, particularly if the source is
5 renewable. For example, Pedro and Putsche [7] estimate that using wind
energy, hydrogen production costs alone will amount to $20.76 per tank to drive
our FCV 300 miles compared to $4.28 per tank (or per charge) for the BEV.4
2.2. Comparison of Weight, Volume and Cost Maintaining the same performance
assumptions, we next compare the projected relative weight, volume, and
unit costs of each vehicles propulsion system. The results are reported in Table
1 and Table 2. When interpreting the tables it is important to note that the
limiting factor in FCV performance is the amount of power that can be delivered,
which affects vehicle acceleration and hill climbing. For BEVs, the limiting factor
is the amount of energy that can be delivered, which affects total vehicle
range. This means that the scaling factors for weight, volume, and cost for
the FCV are based on how many Watts (of power) that can be delivered per unit
of weight, volume, or cost. For the BEV it is the amount of Watt·hours (of
energy) that can be delivered per unit of weight, volume, or cost.
Table 1
Estimated weight, on-board space, and mass-production cost requirements of the FCV
propulsion system.
Component Weight Volume Cost Reference
Fuel-Cell 617 kg 1182 liters $23,033 ADL(2001)
3.2 kg storage tank 51 kg 215 liters $2,288 Padro and Putsch(1999)
Drivetrain 53 kg 68 liters $3,826 AC Propulsion,
Inc.(2001),
Total 721 kg 1465 liters $29,147 SolectriaCorp (2001)
Table 2
Estimated weight, on-board space, and mass-production cost requirements of a BEV
propulsion systems
Component Weight Volume Cost Reference
Li-ion Battery 451 kg 401 liters $16,125 Gaines and Cuenca(2000)
Drivetrain 53 kg 68 liters $3,826 Cuenca and Gains
Total 504 kg 469 liters $19,951
2.3. Weight Comparison
According to the DOE report on the status of fuel-cells conducted by Arthur
D. Little [8], a modern fuel cell is presently capable of delivering 182 Watts
of power per kg of fuel-cell. Including the required FCV drivetrain components
and their losses [9,10] and the weight of the storage tank5, a fuel-cell propulsion
system capable of meeting our performance constraint must weigh
approximately 721 kg. According to the National Renewable Energy Laboratory
(NREL) working group report on advanced battery readiness [11], a
Lithium-ion battery is capable of delivering 143 Watts·hours of energy per
kg of battery. Considering an equivalent drivetrain to the one assumed for the
FCV, the battery system must weigh 504 kg to satisfy our performance constraint.6
2.4. Volume Comparison
The Arthur D. Little study reports that the fuel-cell delivers 95 Watts per
liter of fuel-cell, which combined with the volume of the hydrogen storage tank
[12] and the volume of the electric drivetrain components produces a total
volume of 1465 liters.7 A Lithium-ion battery delivers 161 Watt·hours per liter
of battery.8 When combined with the electric drivetrain volume, this results in
a total volume of 469 liters. 2.5. Cost Comparison Finally, The Arthur D. Little
study reports a cost of $205 per kW for a 100kW fuel-cell.9 Adding to this the cost
of the electric motor, control electronics and hydrogen-storage tank implies that
the total cost of $29,147 for the fuel-cell propulsion system(The electric drivetrain
components are $3,826 for the BEV and FCV.) [13]. For the BEV, the cost of a
Lithium-ion battery is estimated to be $250/kWh [14]. Considering the electric
drivetrain, this implies a total cost of $19,951 for the BEV?s propulsion system.
2.6. Energy Efficiency Comparison assuming energy is derived from Fossil Fuels
Most experts are imagining that for many years to come, fossil fuels will be
the main source of the hydrogen or the electricity that powers zero emission
vehicles. In light of this, one should consider the near term case where the
electricity for BEVs is generated using a mix of fossil fuel and non-fossil fuel
sources and the FCV?s hydrogen is reformed from natural gas, as is the norm today.
A 2001 study conducted for the California Air Resources Board found
that when electricity for BEVs is generated using a mix of fossil fuel and
non-fossil fuel and hydrogen is created from natural gas, a BEV pathway is
about 8% more efficient than a FCV pathway. The study also concluded that
the BEV pathway would generate lower greenhouse gas emissions. Although the
efficiency comparison of the two vehicles is much closer than for the non-fossil fuel
case, if the substantial cost of building and maintaining the hydrogen
infrastructure necessary to support the FCV is considered, then the BEV would
clearly be more attractive than the FCV. Further, if renewable energy sources will
eventually replace fossil fuels, then the hydrogen pipeline would at best be
inefficient, and at worst be obsolete. This is because hydrogen producers
would find it more economical to make hydrogen locally by using renewable
electricity to hydrolyze water, rather than purchasing hydrogen transported via
pipeline. Since the nation?s electricity is already generated using an array of fossil
and non-fossil fuel resources, the optimal design of the BEV infrastructure would
not change in the conversion to a nonfossil fuel economy. Lastly, when the non-fossil
fuel assumption is relaxed, the refueling costof a BEV is still far less than that
of the FCV. Pedro and Putsch estimate the retail cost of hydrogen from fossil fuel to
be $2.42 per kg [7]. Given the 3.2 kg of hydrogen necessary to meet our rangeperformance
constraint, this results in a fill-up cost of $7.77 for the FCV.
Accounting for efficiency losses between a BEV?s battery and its wheels,
64.5kWh of energy must be delivered to the BEV battery to assure that 60 kWh is
delivered to its wheels. Considering a 0.89 charger efficiency and a 0.94 battery
efficiency, this implies that 77 kWh of energy must be purchased from the utility
company. Since BEVs will typically be charged at night, an off-peak cost of
$0.06/kWh is applied for the electricity generated from a mix of fossil and nonfossil
fuels. This implies a ?fill-up? cost of $4.63 for the BEV, which is about
40% lower than that of the FCV.
3. Conclusion
We use widely-cited government studies to directly compare the costs
associated with producing and refueling FCVs and BEVs. The analysis is based
on an automobile model (similar to a Honda Civic) that is representative of the
largest segment of the automobile market. A comparison is important since
the government and industry are devoting increasing amounts of resources
to the goal of developing a marketable ZEV and the BEV and the FCV are
currently the only feasible alternatives. We find that government studies
indicate that it would be far cheaper, in terms of production and refueling costs,
to develop a BEV, even if we do not consider the substantial cost of building
and maintaining the hydrogen infrastructure on which the FCV would
depend. Specifically, the results show that in an economy based on renewable
energy, the FCV requires production of between 2.4 and 2.6 times more energy
than a comparable BEV. The FCV propulsion system weighs 43% more,
consumes nearly three-times more space onboard the vehicle for the same power
output, and costs approximately 46% more than the BEV system. Further, the
refueling cost of a FCV is nearly threetimes greater. Finally, when we relax the
renewable energy assumption, the BEV is still more efficient, cleaner, and vastly
less expensive in terms of manufacturing, refueling, and infrastructure investment.
REFERENCES
1 U.S. Environmental Protection Agency, Light-Duty Automotive Technology and Fuel
Economy Trends 1975-2001, 2001.
2 Northeast Advanced Vehicle Consortium (under contract to Defense Advanced Research
Projects Agency), Interviews with 44 Global Experts on the Future of Transportation and
Fuel Cell Infrastructure and a Fuel Cell Primer, Agreement No. NAVC1099-PG030044,
2000.
3 General Motors, Argonne National Laboratory, BPAmoco, Exxon Mobile, and Shell,
Well-to-Wheels Energy use and Greenhouse Gas Emissions of Advanced Fuel/Vehicle
Systems, 2001.
4 CA Energy Commission and the Air Resource Board, A Fuel Cycle Energy Conversion
Efficiency Analysis, 2000.
5 CA Energy Commission and the Air Resource Board, A Fuel Cycle Energy Conversion
Efficiency Analysis, 2000.
6 U.S. Department of Energy, Annual Progress Report, 2003.
7 Padro, C., V. Putsche, Survey of Economics of Hydrogen Technologies, National
Renewable Energy Laboratory Study NREL/TP-570-27079, 1999.
8 Arthur D. Little, Inc. report to Department of Energy, Cost Analysis of Fuel Cell System
for Transportation, Ref. No. 49739, SFAA No. DESC02-98EE50526, 2001.
9 AC Propulsion Inc., AC150 GEN-2 EV Power System Specification Document, 2001.
10 Solectria Corp., DMC0645 AC Motor Controller Specification, 2001.
11 National Renewable Energy Laboratory, Advanced Battery Readiness Ad Hoc Working
Group Meeting Report 2000.
12 Padro, C., V. Putsche, Survey of Economics of Hydrogen Technologies, National
Renewable Energy Laboratory Study NREL/TP-570-27079, 1999.
13 Cuenca, R., L. Gaines, A. V., Evaluation of Electric Vehicle Production and Operating
Costs, Center for Transportation Research, Argonne National Laboratory, 1999.
14 Gaines, L., R. Cuenca, Costs of Lithium Ion Batteries, Center for Transportation
Research, Argonne National Laboratory, 2000.
Copyright 2008. Sam McWilliam. All rights reserved.
Time For Evs
*The Problem
Something must be done. I'll bet you have said these very words about the HIGH price of gasoline?
Well, it seems that there are a lot of people doing something. Those are the people converting their cars to plug in electric. The big auto manufacturers are talking up hybrids. They are a step in the right direction but not the ultimate answer. Electric vehicles are the answer. If Joe Blow can do it in his garage, why can't GM? Fuel cells require a whole new infrastructure. Electric is there now! Oil companies shudder when electric is mentioned.No need for their product. Too bad
our Government is so beholden to these leaches. Parasites flock together( just like birds). Do you realize that every time the price of gas rises they get more of our money to squander on themselves! The "war" also puts lots of money in the pockets of the military and the oil companies. Why isn't the rebuilding of Iraq paid for with their oil? They had a 50 billion dollar surplus while we Had a 400 billion deficit!
*What can be done
Get the word out that elctric vehicles can be as user friendly , need less repairs ,and cost less to run than internal combustion vehicles. Continue to retrofit our own cars with plug in electric.
*Why hasn't this been done
1 Not in big oil's interest (obvious)
2 politicians want their bribes from big oil and taxes on fuel. It keeps them in office and pays the high salary
and perks.
3 big auto companies make more money on the ICE engine and all the repairs necessary. Not to mention the price
to you and I (think Suv's and Hummers).
* What is being done
People like you and I all over the world are taking it into their own hands and not waiting for the big auto
companies to make electric cars. They are doing it themselves.
Something must be done. I'll bet you have said these very words about the HIGH price of gasoline?
Well, it seems that there are a lot of people doing something. Those are the people converting their cars to plug in electric. The big auto manufacturers are talking up hybrids. They are a step in the right direction but not the ultimate answer. Electric vehicles are the answer. If Joe Blow can do it in his garage, why can't GM? Fuel cells require a whole new infrastructure. Electric is there now! Oil companies shudder when electric is mentioned.No need for their product. Too bad
our Government is so beholden to these leaches. Parasites flock together( just like birds). Do you realize that every time the price of gas rises they get more of our money to squander on themselves! The "war" also puts lots of money in the pockets of the military and the oil companies. Why isn't the rebuilding of Iraq paid for with their oil? They had a 50 billion dollar surplus while we Had a 400 billion deficit!
*What can be done
Get the word out that elctric vehicles can be as user friendly , need less repairs ,and cost less to run than internal combustion vehicles. Continue to retrofit our own cars with plug in electric.
*Why hasn't this been done
1 Not in big oil's interest (obvious)
2 politicians want their bribes from big oil and taxes on fuel. It keeps them in office and pays the high salary
and perks.
3 big auto companies make more money on the ICE engine and all the repairs necessary. Not to mention the price
to you and I (think Suv's and Hummers).
* What is being done
People like you and I all over the world are taking it into their own hands and not waiting for the big auto
companies to make electric cars. They are doing it themselves.
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