Jean-Paul Rodrigue (2017), New York:
Routledge, 440 pages.
Transportation and Energy
Authors: Dr. Jean-Paul Rodrigue and Dr. Claude Comtois
Human activities are closely dependent on the usage of several
forms and sources of energy
to perform work. Energy is the potential that allows movement
and/or the modification of matter (e.g. making steel by
combining iron and carbon). The
energy content of an energy
source is the available energy per unit of weight or volume,
but the challenge is to effectively extract and use this
energy. Thus, the more energy consumed the greater the amount
of work realized and it comes as no surprise that economic
development is correlated with greater levels of energy
consumption. There are four types of physical work related
to human activities:
There are enormous reserves of energy able to meet the future
needs of mankind. Unfortunately, one of the main contemporary
issues is that many of these reserves are not necessarily
available at competitive costs, such as solar energy, or
are unevenly distributed around the world, such as oil.
Still, the competitiveness of an energy source can improve
with technological development and even if some energy sources
are extracted far from where they are consumed, the massification
of transportation enables to move them. Through the
history of mankind's use of
energy, the choice of an energy source depended on a
number of utility factors which involved a
transition in energy systems
from solid, liquid and eventually to gas sources of energy.
Since the industrial revolution, efforts have been made
to have work being performed by
machines, which considerably improved industrial productivity.
The development of steam engine and the generation and distribution
of electric energy over considerable distances have also
altered the spatial pattern of manufacturing industries
by liberating production from a direct connection to a fixed
power system. While in the earlier stages of the industrial
revolution factories located close to sources of energy
(a waterfall or a coal field) or raw materials, mass conveyances
and new energy sources (electricity) enabled a much greater
Industrial development places large demands on fossil fuels.
At the turn of the 20th century, the invention and commercial
development of the internal combustion engine, notably in
transport equipment, made possible the efficient movement
of passengers and freight and incited the development of
a global trade network. With globalization, transportation
is accounting for a growing share of the total amount of
energy spent for implementing, operating and maintaining
the international range and scope of human activities. Energy
consumption has a strong correlation with the level of development.
Among developed countries, transportation now accounts between
20 and 25% of the total energy being consumed. The benefits
conferred by additional mobility, notably in terms of a
better exploitation of comparative advantages, have so far
compensated the growing amount of energy spent to support
it. At the beginning of the 21st century, the transition
reached a stage where fossil
fuels, notably petroleum, are dominant. Out of the
world’s total power
production, 87.1% is derived from fossil fuels.
2. Transportation and Energy Consumption
Transportation and energy is a start a standard physics
application where giving momentum to a mass (people, vehicles,
cargo, etc.) requires a proportional amount of energy. The
relationship between transport and energy is a direct one,
but subject to different interpretations since it concerns
different transport modes,
each having their own utility and level of performance.
There is often a compromise between speed
and energy consumption, related to the
desired economic returns. Passengers and high value goods
can be transported by fast but energy intensive modes since
the time component of their mobility tends to have a high
value, which conveys the willingness to use more energy.
Economies of scale, mainly those achieved by maritime transportation,
are linked to low levels of energy consumption per unit
of mass being transported, but at a lower speed. This fits
relatively well freight transport imperatives, particularly
for bulk. Comparatively, air freight has high energy consumption
levels linked to high speed services. Transportation markets
are particularly impacted by three energy issues:
- Modification of the environment. All the activities
involved in making space suitable for human activities,
like clearing land for agriculture, modifying the hydrography
(irrigation), and establishing distribution infrastructures,
as wells as constructing and conditioning (temperature and
light) enclosed structures.
- Appropriation of resources. Involves the extraction
of agricultural resources from the biomass and raw materials
(minerals, oil, lumber, etc.) for human needs. It also includes
the disposal of wastes, which are in an advanced industrial
society very work intensive to safely dispose of (e.g. collection,
treatment and disposal).
- Processing resources. Concerns the modification
of products from the biomass, of raw materials and of goods
to manufacture according to economic needs. Over the last
200 years, work related to processing was considerably mechanized
(e.g. assembly lines).
- Transfer. Involves the movement of freight, people
and information from one location to another. It aims to
attenuate the spatial inequities in the location of resources
by overcoming distance. The less energy costs per ton or
passenger - kilometer, the less importance have transfers.
Overcoming space in a global economy requires a substantial
amount of work and thus energy and has consequently been
subject to massive economies of scale.
A trend that emerged since the 1950s concerns the growing
share of transportation in the world's
total oil consumption; transportation
accounts for approximately 25% of world energy demand and
for about 61.5% of all the oil used each year. The impacts
of transport on energy consumption are diverse, including
many that are necessary for the provision of transport facilities:
- The price level
and volatility of energy sources which are dependent
on the processes
used in their production. Stable energy sources are obviously
- Technological and technical changes
in the level of energy performance
of transport modes and terminals. An important goal is thus
to improve this energy performance since it is linked with
direct economic benefits for both operators (lower operating
costs) and users (lower rates).
- Environmental externalities related
to the use of specific modes and energy sources and the
goal to reduce them.
Energy consumption has strong modal variations:
- Vehicle manufacture, maintenance and disposal.
The energy spent for manufacturing and recycling vehicles
is a direct function of vehicle complexity, material used,
fleet size and vehicle life cycle.
- Vehicle operation. Mainly involves energy used
to provide momentum to vehicles, namely as
fuels, as well as for intermodal
operations. The fuel markets
for transportation activities are well developed.
- Infrastructure construction and maintenance.
The building of roads, railways, bridges, tunnels, terminals,
ports and airports and the provision of lighting and signaling
equipment require a substantial amount or energy. They have
a direct relationship with vehicle operations since extensive
networks are associated with large amounts of traffic.
- Management of transport business. The expenses
involved in planning, developing and managing transport
infrastructures and operations involves time, capital and
skill that must be included in the total energy consumed
by the transport sector. This is particularly the case for
- Energy production and trade. The processes of
exploring, extracting, refining and distributing fuels or
generating and transmitting energy also require power sources.
The transformation of 100 units of primary energy in the
form of crude oil produces only 85 units of energy in the
form of gasoline. Any changes in transport energy demands
influence the pattern and flows of the world’s energy markets.
Further distinctions in the energy consumption of transport
can be made between passenger and freight movements:
- Land transportation accounts for the great majority
of energy consumption. Road transportation alone is consuming
on average 85% of the total energy used by the transport
sector in developed countries. This trend is not however
uniform within the land transportation sector itself, as
road transportation is almost the sole
mode responsible for additional
energy demands over the last 25 years. Despite a falling
market share, rail transport, on the basis of 1 kg of oil
equivalent, remains four times more efficient for passenger
and twice as efficient for freight movement as road transport.
Rail transport accounts for 6% of global transport energy
- Maritime transportation accounts for 90% of cross-border
world trade as measured by volume. The nature of water transport
and its economies of scale make it the most energy efficient
mode since it uses only 7% of all the energy consumed by
transport activities, a figure way below its contribution
to the mobility of goods. For terminal operations, figures
vary, but a container terminal usually have 70% of its energy
consumption provided by fossil fuels (e.g. yard equipment)
and 30% by electricity (e.g. portainers).
- Air transportation plays an integral part in
the globalization of transportation networks. The aviation
industry accounts for 8% of the energy consumed by transportation.
Air transport has high energy consumption levels, linked
to high speeds. Fuel is the second most important cost for
the air transport industry accounting for 13-20% of total
expenses. Technological innovations, such as more efficient engines
and better aerodynamics, have led to a continuous improvement
energy efficiency of each new generation of aircrafts.
3. Petroleum: The Transport Fuel
Almost all transportation modes depend on a form of the
internal combustion engine, with the two most salient
technologies being the diesel engine and
the gas turbine, since they are the lynchpin
of globalization. While ship and truck engines are adaptations
of the diesel engine, jet engines are an adaptation of the
gas turbine. Transportation is almost completely reliant
(95%) upon petroleum products with the exception of railways
using electrical power. While the use of petroleum for other
economic sectors, such as industrial and electricity generation,
has remained relatively stable, the growth in oil demand
is mainly attributed to the
growth in transportation demand. What varies is the
type and the quality of petroleum derived fuel being used.
While maritime transportation relies on low quality bunker
fuel, air transportation requires a specialized fuel with
It is worth having a closer look at the chemical combustion
principle of hydrocarbons. For the majority of internal
combustion engines, gasoline (C8H18;
four strokes Otto-cycle engines) serves as fuel, but other
sources like methane (CH4; gas turbines), diesel
(mostly trucks), bunker fuel (for ships) and kerosene (turbofans
of jet planes) are used. In a complete and perfect
combustion of gasoline the following chemical reaction is
- Passenger transportation accounts for 60 to 70%
of energy consumption from transportation activities. The
private car is the dominant mode but has a
poor energetic performance,
although this performance has seen
since the 1970s, mainly due to growing energy prices and
regulations. Only 12% of the fuel used by a car actually
provides momentum. There is a close relationship between
rising income, automobile ownership and distance traveled
by vehicle. The United States has one of the highest levels
of car ownership in the world with one car for every two
people. About 60% of all American households owned two or
more cars, with 19% owning three or more. Another trend
has been the increasing rise in ownership of minivans, sport
utility vehicles and light-duty trucks for personal use
and the corresponding decline in fuel economy. Fuel consumption
is however impacted by
implying that higher levels of fuel efficiency involve declining
marginal gains in fuel consumption. Also, the growth of
vehicles-miles travelled is
correlated with changes
in energy prices and is entering a phase of maturity
in several developed countries.
- Freight transportation is dominated by rail and
maritime shipping, the two most energy efficient modes.
Coastal and inland waterways also provide an energy efficient
method of transporting passengers and cargoes. A tow boat
moving a typical load of 15 barges in tow holds the equivalent
of 225 rail car loads or 870 truck loads. The rationale
for favoring coastal and inland navigation is based on lower
energy consumption rates of shipping and the general overall
smaller externalities of water transportation. The United
States Marine Transportation System National Advisory Council
has measured the distance that one ton of cargo can be moved
with 3.785 liters of fuel. A tow boat operating on the inland
waterways can move one ton of barge cargo 857 kilometers.
The same amount of fuel will move one ton of rail cargo
337 kilometers or one ton of highway cargo 98 kilometers.
Gasoline produces around 46,000 Btu per kilogram combusted,
which requires from 16 to 24 kg of air. The energy released
by combustion causes a rise in temperature of the products
of combustion. Several factors and conditions influence
the level of combustion in an internal combustion engine
to provide momentum and keep efficient operating conditions.
The temperature attained depends on the rate of release
and dissipation of the energy and the quantity of combustion
products. Air is the most available source of oxygen, but
because air also contains vast quantities of nitrogen, nitrogen
becomes the major constituent of the products of combustion.
The rate of combustion may be increased by finely dividing
the fuel to increase its surface area and hence its rate
of reaction, and by mixing it with the air to provide the
necessary amount of oxygen to the fuel.
If all internal combustion engines worked according to the
above equation, emissions and thus local environmental impacts
of transportation would be negligible (except for carbon
dioxide emissions). The problem is that combustion in internal
combustion engines is imperfect and incomplete
for two reasons:
- (2) C8H18 + (25) O2
= (16) CO2 + (18) H2O
In addition to the imperfect and incomplete combustion of
hydrocarbons, three major factors
influence the rate of combustion and thus emissions of pollutants,
which are the characteristics of vehicles (where technological
improvements can play a role), driving characteristics (where
planning and regulation can play a role), and atmospheric
conditions. The internal combustion engine, mostly due to
friction, converts less than a third of the energy they
consume into momentum. For electric motors, this figure
is above 80%.
4. Transportation and Alternative Fuels
All other things being equal, the energy source with the
lowest cost will always be preferred. The dominance of petroleum-derived
fuels is a result of the relative simplicity with which
they can be stored and efficiently used in the internal
combustion engine vehicle. Other fossil fuels (natural gas,
propane, and methanol) can be used as transportation fuels
as well but require a more complicated storage system.
The main issue concerning the large-scale uses of alternative
vehicle fuels is the large capital investments required
in distribution facilities as compared with conventional
fuels. Another issue is that in terms of energy
density, these alternative fuels have lower efficiency
than gasoline and thus require greater volume of on-board
storage to cover the equivalent distance as a gasoline propelled
vehicle if performance is kept constant.
Alternative fuels in the form of non-crude oil resources
are drawing considerable attention as a result of the non-renewable
character of fossil fuels and the need to reduce emissions
of harmful pollutants. The most prevalent alternatives being
- First, the fuel and the oxider are not pure,
causing an imperfect combustion. Although the refining process
provides a "clean" fuel, gasoline is known to
have impurities such as sulfur (0.1 to 5%), sometimes lead
(anti-knock agent being phased out) and other hydrocarbons
(like benzene and butadiene), while air is composed of 78%
nitrogen and 21% oxygen. Thus, other chemical components
are part of the combustion process.
- Second, in part because of the first reason and in part
because of the technology of the engine, incomplete combustion
emits other residuals. Combustion in an engine occurs
at an average rate of 25 times per second, leaving limited
time for a complete combustion process. Besides carbon dioxide
and water, a typical internal combustion engine will produce
carbon monoxide (CO), hydrocarbons (benzene, formaldehyde,
butadiene and acetaldehyde), volatile organic compounds
(VOC), sulfur dioxide (SO2), particulates, and
nitrogen oxides (NOx). These combustion products
are the main pollutants emitted in the environment by transportation.
The diffusion of non-fossil fuels in the transportation
sector has serious limitations. While the price of
oil has increased over time, it has been subject to significant
fluctuations. The comparative costs of alternative energy
sources to fossil fuels are higher in the transportation
sector than in other types of economic activities. This
suggests higher competitive advantages for the industrial,
household, commercial, electricity and heat sectors to shift
away from oil and to rely on solar, wind or hydro-power.
Transportation fuels based on renewable energy sources might
not be competitive with petroleum fuels unless of significant
5. Transportation and Peak Oil
The extent to which conventional non-renewable fossil fuels
will continue to be the primary resources for nearly all
transportation fuels is subject to debate. But the gap between
demand and supply, once considerable, is narrowing,
an effect compounded by the
peaking off of global oil production. The steady surge
in demand from developing economies, particularly China
and India, requires additional outputs. This raises concern
about the capacity of major oil producers to meet this rising
world demand. The producers are not running out of oil,
but the existing reservoirs may not be capable of producing
on a daily basis the increasing volumes of oil that the
world requires. Reservoirs do not exist as underground lakes
from which oil can easily be extracted. There are geological
limits to the output of existing fields. This suggests that
an additional reserves need to be found to compensate for
the declining production of existing fields. Reserves additions
may not be enough to offset this growing demand. The bitumen
reserves in Alberta, Canada for instance are estimated at
170 billion barrels, second in the world in terms of oil
reserves, behind Saudi Arabia. But extracting heavy oil
from sands bitumen necessitates much energy and water. The
production of 1 barrel of bitumen requires burning 10-20%
of the energy content of the resulting crude oil in the
form of natural gas.
Others argue that the history of the oil industry is marked
by cycles of shortages and surplus. The rising price
of oil will render cost effective oil recovery in difficult
areas. Deep water drilling, extraction from tar sands and
oil shale should increase the supply of oil that can be
recovered and extracted from the surface. But there is a
limit to the capacity of technological innovation to find
and extract more oil around the world and the related risks
can be very high. Technological development does not keep
pace with surging demand. The construction of drilling rigs,
power plants, refineries and pipelines designed to increase
oil exploitation is a complex and slow process. The main
concern is the amount of oil that can be pumped to the surface
on a daily basis. Some studies predict that carbon sequestration
in the form of CO2 capture and storage, if technically and
economically viable, could enhance the recovery of oil from
conventional wells and prolong the life of partially depleted
oil fields well into the next century.
High fuel prices
could stimulate the development of alternatives, but
automotive fuel oil is relatively inelastic. Higher prices
result in very marginal changes in demand for fuel. While
the equivalent of $100 per barrel was for a long time considered
a threshold that would limit demand for automotive fuel
and lead to a decline in passenger and freight-km, evidence
suggests that higher oil prices had limited impact on the
average annual growth rate of world motorization. The analysis
of the evolution of the use of fossil fuels suggests that
in a market economy the introduction of alternative fuels
is leading to an increase in the global consumption of both
fossil and alternative fuels and not to the substitution
of crude oil by alternative fuels. This suggests
that in the initial phase of an energy transition cycle,
the introduction of a new source of energy complements existing
supply until the new source of energy becomes price competitive
to be an alternative. The presence of both renewable and
non-renewable types of fuels stimulates the energy market
with the concomitant result of increasing greenhouse gas
emissions. The production of alternative fuels adds up to
the existing fossil fuels and does not replace it.
The main concern is the amount of oil that can be pumped
to the surface on a daily basis, especially where major
oil fields have reached peak capacity. Under such circumstances,
oil prices are bound to rise in a substantial way, sending
significant price signals to the transport market. How the
transport system will respond and adapt to
higher energy prices
is obviously subject to much debate and interpretations.
The following potential consequences can be noted:
- Biofuels such as ethanol, methanol
and biodiesel can be produced from the fermentation of food
crops (sugar cane, corn, cereals; often called first generation
biofuels) or the biomass (such as wood and grasses; called
second generation biofuels). Their production however requires
large harvesting areas that may compete with other types
of land use. This limit is related to the capacity of plants
to absorb solar energy and transform it through photosynthesis.
This low productivity of the biomass does not meet the energy
needs of the transportation sector. Besides, the production
of ethanol is an energy-intensive process. Biodiesel
can also be obtained from a variety of crops. The choice
of biomass fuel will largely depend on the sustainability
and energy efficiency of the production process.
- Hydrogen is often mentioned as the energy source
of the future. The steps in using hydrogen as a transportation
fuel consist in producing hydrogen by electrolysis of water
or by extracting it from hydrocarbons. Then, compressing
or converting hydrogen into liquid form and storing it on-board
a vehicle. Finally, using fuel cell to generate electricity
on demand from the hydrogen to propel a motor vehicle. Hydrogen
fuel cells are more efficient than gasoline and generate
near-zero pollutants. But hydrogen suffers from several
problems, particularly since a lot of energy can be wasted
in its production, transfer and storage. Hydrogen manufacturing
requires electricity production. Besides, hydrogen has a
very low energy density and requires very low temperature
and very high pressure storage tank adding weight and volume
to a vehicle. This suggests that liquid hydrogen fuel would
be a better alternative for ship and aircraft propulsion.
- Electricity is being considered as an alternative
to petroleum fuels as an energy source. A pure battery electric
vehicle is considered a more efficient alternative to hydrogen
fuel propelled vehicle as there is no need to convert energy
into electricity since the electricity stored in the battery
can power the electric motor. Besides an all electric car
is easier and cheaper to produce than a comparable fuel-cell
vehicle. The main barriers to the development electric cars
are the lack of storage systems capable of providing driving
ranges and speed comparable to those of conventional vehicles.
The low energy capacity of batteries makes the electric
car less competitive than internal combustion engines using
gasoline. The current technological level of electric cars
has a range around 430 kilometers, which is steadily increasing.
As technology improves, the energy and cost effectiveness
of batteries is getting better. For instance, between 2010
and 2015, the cost of lithium-ion batteries fell by 65%.
Electric vehicles are eminently suitable for urban transportation
for both passenger and freight because of the lower ranges
- Hybrid vehicles consisting of propulsion system
using an internal combustion engine supplemented by an electric
motor and batteries, which provides opportunities combining
the efficiency of electricity with the long driving range
of an internal combustion engine. A hybrid vehicle still
uses liquid fuel as the main source of energy but the engine
provides the power to drive the vehicle or is used to charge
the battery via a generator. Alternatively, the propulsion
can be provided by the electricity generated by the battery.
When the battery is discharged, the engine starts automatically
without intervention from the driver. The generator can
also be fed by using the braking energy to recharge the
battery. Such a propulsion design greatly contributes to
overall fuel efficiency. Given the inevitable oil depletion,
the successful development and commercialization of hybrid
vehicles appears on the medium term the most sustainable
option to conventional gasoline engine powered vehicles.
Higher energy prices will trigger notable changes in usage,
modes, networks and supply chain management. From a macro
perspective, and since transportation is a very complex
system, assessing the outcome of high energy prices remains
hazardous. What appears very likely is a strong rationalization,
a shift towards more energy efficient modes as well as a
higher level of integration between modes to create multiplying
effects in energy efficiency. As higher transport costs
play in, namely for containers,
many manufacturing activities will reconsider the locations
of production facilities to sites closer to markets (near-sourcing).
While globalization was favored by cheap and efficient transport
systems, the new relationships between transport and energy
are likely to restructure the global structure of production
and distribution towards regionalization.
- Road. As far as the automobile is concerned,
higher oil prices could trigger changes in several phases.
Initially, commuters would simply absorb the higher costs
either by cutting on their discretionary spending. Depending
on their level of productivity, many economies could show
a remarkable resilience. The next phase would see changes
in commuting patterns (e.g. carpooling), attempts to use
public transit, a rapid adoption of vehicles with high gasoline
efficiency (in the United States, this could mark the downfall
of the SUV) and a search for other transport alternatives.
The existing spatial structure could also start to show
signs of stress as the unsustainability of car dependent
areas become more apparent. There is already evidence that
car mobility may have been reached in the United States.
As high commuting costs and the inflationary effects of
high oil prices on the economy become apparent many would
no longer be able to afford living in a suburban setting.
Cities could start to implode. The trucking industry would
behave in a similar way, first by lowering their profits
and their operating expenses (e.g. scheduling, achieve FTL),
but at some point, higher prices will be passed on to their
- Rail. This mode is set to benefit substantially
from higher energy prices as it is the most energy efficient
land transportation mode. Rail is about three times more
energy efficient than trucking. The level of substitution
for passengers and freight remains uncertain and will depend
on the current market share and level of service they offer.
In North America, passenger rail has limited potential while
in Europe and Pacific Asia passenger rail already assume
a significant market share. For rail freight, North American
freight distribution has an advantage since rail account
for a dominant share of tons-km while this figure is less
significant for other regions of the world, mainly due to
the distances involved and the fragmentation of the system.
In many cases, there could a pressure towards the electrification
of strategic long distance corridors and the development
of more efficient cargo handling facilities. Thus, growing
energy prices are likely to affect long distance rail transportation
differently depending on the geographical setting and the
conditions of the existing system.
- Air. This mode could be significantly impaired,
both for passengers and freight. Air transportation is a
highly competitive industry and the profit margins tend
to be low. Fuels account for about 15% of the operating
expenses of an air carrier, but because most of the other
costs are fixed any variations in energy prices is reflected
directly on air fares. A long term increase in energy prices,
is likely to impact discretionary air travel (mainly tourism),
but air freight, due to its high value, may be less impacted.
Technological developments are helping maintaining the competitiveness
of air transportation with
more fuel efficient planes.
- Maritime. This mode is likely to be relatively
unaffected as it is the most energy efficient, but fuel
is an important component of a ship's operating costs.
The response of maritime shippers over higher energy prices
tends to be lowering speed (slow
steaming), which may have impacts on port call scheduling.
On the long run, higher energy prices may however indirectly
impact maritime transportation by lowering demand for long
distance cargo movements and incite port calls at ports
having the most direct and efficient hinterland connections.
In addition, this context may favor the development of short
coastal and fluvial services where possible.