|In 1973, petroleum shortages
caused by the OPEC oil embargo launched the world's industrialized nations on a search for
more efficient homes, factories, and transportation systems. After two decades of attempts
to economize, energy use in the residential sector is about the same, industrial energy
use is down, and transportation energy use is up. Today, we are more concerned with the
other side of the coin - the environmental problems and long-term economic perils of
unbridled energy consumption.
Trends in Transportation Energy Consumption:
Transportation now consumes more than 20% of the world's total primary energy and
produces much of the world's air pollution. In just 30 years, the number of cars in the
world will soar from today's 400 million or so, to more than one billion. Private
transportation will then need 2-1/2 times more energy and produce 2-1/2 times more air
pollution. If global trends are projected to year 2100, the world will need 10 times more
total energy, and transportation will consume 40% of this much larger pool.(1)
Energy Use, Global Warming, and Climatic Changes:
Energy use and emissions trends point to significant economic, political, and social
problems for future generations. The greenhouse effect alone could have devastating
effects on economies. Without intervention, the buildup of greenhouse gases could reach
twice the pre-industrial level as early as 2030. The resulting global warming effect could
raise sea levels enough to threaten wetlands, increase coastal flooding, and accelerate
coastal erosion. The Intergovernmental Panel on Climate Change (IPCC) estimated that sea
levels will rise an average of 6 to 20 inches by 2050. In addition, many unmanaged
ecosystems will probably be lost. Changes in rainfall patterns will likely result in more
severe droughts, more intense tropical storms, and ultimately, dislocations and reductions
in agricultural output. (Despite the increased crop yield associated with higher carbon
dioxide levels, the resulting climatic changes are expected to shift agricultural
production to regions having less productive topsoil, which would then result in
diminished total yields.)
About 75% of human emissions of carbon dioxide, the most important man-made greenhouse
gas, is caused by the use of fossil fuels. Fossil fuel use has caused an imbalance in the
earth's normal carbon cycle. Normally, biologic growth absorbs carbon from the environment
and then releases it back into the environment when it decays or is burned. New growth
then absorbs the carbon again, and the amount of carbon in the environment remains roughly
the same. Since the last ice age, the level of carbon in the atmosphere (in the form of
carbon dioxide) has varied only about 5%. However, fossil fuel use has upset the balance.
Over the earth's history, large amounts of carbon had been removed from the environment
and become locked away beneath the surface where it was ultimately transformed into fossil
fuel deposits. Since the industrial revolution, humankind has been removing these
deposits, burning the fuel, and releasing the carbon into the atmosphere. The result is a
rapid buildup of atmospheric carbon dioxide that is unprecedented in the history of human
life on earth. No one knows the precise effects, but for better or for worse, average
temperatures will increase and global weather patterns will change.
Limited Supplies of Traditional and Inexpensive Energy:
Nearly 40% of the world's energy now comes from petroleum, and another 21% comes from
natural gas.(2) Together, these finite natural resources supply about 60% of the world's
energy. If oil and natural gas consumption continued to double every 15 to 20 years as it
had for the 100 years preceding 1973, the earth's entire original endowment of these
resources would be 80% depleted in another 30 years or so. As early as 1970, new oil and
gas discoveries had dramatically declined and have remained low. In the '80s, experts
estimated that U.S. reserves would last about 35 years at existing pumping rates. More
recently, estimates have been revised downward. Considering known reserves and estimated
undiscovered deposits, U.S. oil will be depleted in about 10-12 years at present pumping
rates. And new finds will make little difference on a worldwide scale. A new Prudhoe Bay
discovery would provide the world with about six months' oil supply, and a new North Sea
find would equate to about three years' supply.(3)
Each year, the demand for oil is increasing by an amount equal to Kuwait's entire
annual production, and for the first time, OPEC has no substantial excess production
capacity. Because of declining and more costly-to-recover petroleum reserves, prices are
expected to begin rising in the mid to late '90s, and continue to rise thereafter.(4)
The challenge of alternative fuels is primarily an economic one. Although the
volumetric cost of methanol (made from natural gas) and ethanol (made from corn) is on par
with gasoline, a car running on ethanol consumes 50 percent more fuel and an ethanol car
consumes about twice the fuel per mile traveled, in comparison to a car running on
gasoline. Consequently, per-mile fuel costs are greater. Natural gas is less costly on a
per-mile basis than today's gasoline, but supplies are finite and the high cost of natural
gas vehicle systems generally offset the lower cost of the fuel itself. Although
environmentally friendly, hydrogen is both technically and economically challenging due to
its high production costs and the difficulty of storing hydrogen on-board vehicles.
Alternative fuels do not save primary energy, but they are cleaner than gasoline. Carbon
dioxide levels remain essentially unchanged when alcohol fuels are made from renewable
Renewable biomass fuels, such as ethanol and methanol, may become economically
competitive with petroleum motor fuels by year 2000. But much remains uncertain about the
world's capacity to produce biomass in quantities sufficient to meet future energy needs.
Already, about half the world's solar energy captured by photosynthesis is used by humans,
primarily for food and forest products. Total primary energy use in the U.S. amounts to
about 31 times more energy than is harvested as crops and forest products, and about 40%
more energy than is captured by all forms of U.S. vegetation, combined. Considering all
agricultural crops, forests, lawns, gardens and wild vegetation, the energy contained in
annual U.S. vegetation growth totals about 54 quads (quadrillion BTUs), and in year 1990
total U.S. primary energy consumption amounted to approximately 81 quads.
Because of limitations in water supplies, nutrients, and arable lands, the amount of
energy obtainable from the world's agricultural resources is limited. Even in the U.S.,
which has more arable land per capita than any other nation on earth, it may be infeasible
to produce biomass fuels in quantities sufficient for the nation's energy needs. According
to Dr. David Pimentel, Cornell University, the U.S. has the agricultural capacity to
support a population of about 200 million on biomass energy - only if per capita energy
consumption were reduced to half its present level. Worldwide, the ability of the
ecosystem to sustain a population at an equivalent of U.S. consumption in the '90's is
probably limited to about two billion people, or one-third of the existing population.(5)
Unfortunately, U.S. population is expected to reach 500 million in 60 years, and worldwide
population will reach 12-15 billion near the end of the 21st century.
The world is entering a period of escalating consumption, declining reserves of
traditional energy feedstocks, higher energy costs, and increasing environmental stress,
which could have vast economic, political, and social ramifications. As environmental
limitations are approached, ecosystems become more unstable. In the future, ecosystem
management and environmental maintenance will become more the responsibility of humans
rather than nature. The economic impact of higher energy costs will be compounded as the
cost of environmental protection and repair is included in the fundamentally higher cost
of energy. As a result, varying degrees of negative economic effects are likely.
Ultimately, a fundamental restructuring of the way in which energy is produced and
consumed, as well as its value and role in the economy, must occur, regardless of the
particular energy technology. Reducing the energy intensity of industrialized societies is
the most environmentally sound and least economically harmful strategy. Energy use must be
constrained if the interrelated problems of energy supplies, environmental degradation,
and economic well-being are to be solved.
Transportation is essential to modern economies, and that sector is almost totally
dependent on oil as a source of energy. The ability to freely and inexpensively move goods
and people is a fundamental link in the economic chain. Today, large changes in the price
or supply of oil send shock waves rolling through the world's financial institutions.
Transportation is the most rapidly growing consumer of the world's energy, and the largest
share of transportation's energy goes to passenger travel. In developed countries,
passenger travel accounts for about 70% of the total energy consumed by transportation.
The Automobile's Impact on Transportation Energy Consumption:
The automobile is responsible for nearly 90% of the energy consumed for travel in the
U.S., about 80% in Western Europe, and nearly 60% in Japan.(6) Today, there are
approximately 400 million cars in the world, and sometime around year 2030 the world's
automobile population will surpass one billion. If driving habits remain unchanged, cars
will have to become nearly three times more energy-efficient by 2030 just to maintain that
sector's present consumption. If energy use trends are projected to year 2100,
transportation would then have to be twenty times more energy-efficient, which roughly
equates to 400 mpg cars (automobile fleet-average fuel economy is now about 20 mpg).
Cars in the U.S. have become more energy-efficient over the past two decades, but other
developed countries are losing ground and actually consuming more fuel per passenger mile
traveled.(7) Europeans are turning more to private cars, and as a result transportation
trends and energy use patterns are converging with those of the U.S. But the greatest
increase in transportation energy consumption will occur in the developing world. By year
2010, India is expected to have 36 times more cars than in 1990. China will have 91 times
more cars, Mexico will have 2-1/2 times more cars, and Eastern Europe and the countries of
the former U.S.S.R. will probably double their automobile population. The rest of the
developing world will experience a 300% increase over the same period. In comparison, the
number of cars in the U.S., Canada, Western Europe, and Japan will have grown by only
The Automobile's Role in Atmospheric Pollution:
In a typical U.S. city, motor vehicle emissions account for 30%-50% of hydrocarbon,
80%-90% of carbon monoxide, and 40%-60% of nitrogen oxide emissions. Cars and light trucks
are responsible for about 20% of the nation's carbon dioxide, which is a powerful
greenhouse gas. Motor vehicle carbon emissions are essentially proportional to total fuel
consumed.(9) Unfortunately, in the coming decades the greatest growth in the automobile
population will occur in developing countries which can least afford clean technologies.
The United Nations Fund for Population Activities estimates that, because of rapidly
increasing automobile populations, developing countries will be emitting 16.6 billion tons
of carbon dioxide annually by year 2025, or about four times as much as developed nations.
Problems Are Interdependent:
Transportation energy consumption and environmental health are interrelated issues.
Relieving the demand side of the equation simultaneously relieves the rest. If vehicle
fuel economy were doubled, for example, transportation emissions would be essentially cut
in half, even if there were no improvement in emission control technologies. If petroleum
consumption were cut in half, reserves would be effectively doubled, even though no new
deposits had been discovered. With a doubling of vehicle fuel economy, the same number of
vehicle miles could be supported on half the investment in exploratory drilling, half the
recovery, refining, and delivery expenses, and half the damage to the environment. The
same interrelationships would exist with alternative energy sources, regardless of the
Although each problem, from emissions and resource burdens to economic factors, may
yield to their own targeted efforts, alleviating the fundamental problem simultaneously
reduces the entire spectrum of associated difficulties.
The Automobile as a Transportation System:
Mass transit is often mentioned as an alternative to private cars, but the most
effective mass transit system in the world is the automobile. An automobile transportation
system provides schedules and routes that are tailored to individual needs. In addition,
users individually purchase, maintain, and fuel the transportation device, and only the
relatively inexpensive roadways require public funding.
The primary tradeoffs for this otherwise ideal system are high energy intensity and
high emissions.(10) However, if the automobile is to survive as an economically sound and
viable transportation system its energy consumption and harmful emissions must be reduced.
The Potential Impact of New Technologies:
Today, automobiles operate at approximately 15% efficiency, which means that about 15%
of the energy contained in the fuel is delivered to the drive wheels as useful work.
According to the best estimates, it may be possible to double automobile energy efficiency
(using conventional powertrains) to about 30% before we run out of ideas. At 30%
powertrain efficiency a 20- to 25-mpg sedan would then achieve fuel economy of 40 to 50
mpg. Advanced power systems and reduced vehicle roadloads are necessary in order to make
significant gains in automobile energy intensity.
Electric cars produce significantly fewer harmful emissions, and they save about 10% to
30% in primary energy (over the entire energy chain). Advanced fuel cell vehicles using
methanol reformed on-board into hydrogen may be as much as 2-1/2 times more efficient than
today's cars. Practical automobile fuel cells, however, present enormous economic and
In the final analysis, technology alone may not be able to solve the world's energy
problems: partly because of the limitations of technology, but primarily because of the
economic realities of alternative energy systems. And even the most optimistic estimations
of the energy savings obtainable with advanced-technology systems still fall short of
accommodating the long-term forecasts of transportation's energy needs.
A reduction in personal transportation energy intensity is essential in order to reduce
the economic impact and technical hurdles of new energy systems and more costly energy
supplies. Energy conservation is the most economically sound and environmentally friendly
Factors That Affect Personal-Transportation Energy Consumption:
Transportation energy consumption depends on the mass being transported and the distance
it is transported. The technologies employed determine the efficiency at which the mass
is transported. Consequently, energy consumption can be reduced by developing more
efficient transportation technologies, or by reducing the transported mass and/or
the distance traveled.
The factors of distance and mass are determined largely by social and
economic structures, and by vehicle layout and configuration. In order to reduce the distance
and mass factors, Paulo Solaria envisions self-sufficient cities like Arcosanti in
Arizona in which automobiles are no longer needed. Telecommuting, or working at home and
transferring information, rather than people, is another approach designed to reduce
overall distance and mass.
With revised architectures, and new business and social structures, it is possible to
significantly reduce society's transportation energy needs. The difficulties of such
revisions arise from the economic burdens of restructuring cities, and the psychological
resistance to large scale changes in social and business structures. The technologies,
however, are largely available or just on the horizon.
Reducing the transported mass, independently of the distance traveled,
can also fundamentally reduce transportation's energy requirements. Moreover, mass
reduction need not affect travel habits, social and business structures, or the
architecture of cities. The opportunity for a large reduction in mass becomes
apparent when one considers that the vehicle itself is responsible for approximately 92%
of the transported mass, while the occupants account for only 8%.(11) Most of the
automobile's energy is consumed to transport itself. Mass reduction alone can save more
energy than the most advanced powertrain concepts.
Matching Vehicle Size to Trip Requirements:
From the traditional perspective, the "identified problem" contributing to
the automobile's high energy intensity is low vehicle occupancy. Transportation energy
intensity is a measure of the energy consumed per passenger mile traveled. When a vehicle
is lightly loaded, energy intensity goes up because the vehicle consumes about the same
amount of energy (fuel), regardless of the number of occupants. Operating large,
multi-passenger cars with only one or two occupants is therefore considered the most
wasteful habit affecting the world's consumption of transportation energy.
Worldwide, automobiles operate, on average, with about 1.6 to 1.8 occupants. In the
U.S., approximately 87% of all automobile trips occur with two or fewer occupants. The
average for work related trips is 1.1 occupants per vehicle. One- and two-occupant trips
account for approximately 83% of all vehicle miles traveled in the U.S.(12)
If the same number of travelers were condensed into half the cars (car pooling), total
automobile energy consumption would be reduced by half. But condensing occupants into
fewer vehicles essentially defeats the automobile's primary benefit. Trips must then
accommodate the needs of other occupants, and the automobile is no longer a private and
personal means of transportation.
Traditionally, occupancy-rate is considered a behavioral by-product and therefore
outside the bounds of vehicle technology. However, if the "identified problem"
were redefined, it can easily become a simple technical problem. If the definition were
"inappropriate vehicle size" (rather than underutilization of large cars), the
solution would then be to resize vehicles so they more closely match trip requirements.
Since one- and two-occupant trips predominate, it naturally follows that a category of
smaller vehicles designed for one- and two-occupant local and commuting trips would be
Low-Mass Vehicle Safety:
Small, lightweight cars are normally associated with an increased risk of harm. Traffic
accident statistics generally support the relationship between vehicle size and
injury/fatality rates, with the potential for harm increasing in proportion to the
decrease in vehicle size. (The exception is in Japan, where a special category of
lightweight "kei" cars actually have a lower fatality rate than conventional
large cars.) But with better vehicle designs, historical data can quickly become outmoded.
Cars built today are four times safer than vehicles built in 1969, and they are
approximately 10% smaller and 20% lighter. This is due primarily to improved safety
engineering and modern safety systems.
Although occupant protection becomes more challenging as vehicle size is reduced, it is
technically feasible to produce significantly smaller and lighter vehicles that have a
high degree of safety. Advanced "hard shell" concepts designed to increase
low-mass vehicle safety are already under development in Switzerland. This new approach
utilizes a rigid exterior that is largely identical to the rigid passenger compartment of
conventional cars. During a collision, the rigid exterior of the smaller car causes the
less rigid deformation zone of the larger car to yield and absorb energy. Passenger
ride-down space (for deceleration) in the low-mass car is provided inside the vehicle,
rather than by the traditional exterior deformation zone. Occupant deceleration is
controlled by elastic restraints and air bags. (13)
Vehicle use patterns and operating environment are also important. Cars that operate
primarily in the urban environment do not necessarily have to match the crashworthiness of
larger cars in order to provide equally safe transportation.
New Products and New Market Appeals - The Giant Oil Well Under Detroit:
Market positioning, the implied messages in a product's theme and advertising appeals,
can capitalize on today's environmental and energy concerns, and ultimately have a
powerful effect on energy consumption and pollution. The necessary consumer motivations
and interests already exist. A shift in thinking that disengages manufacturers and
consumers alike from the association of size and mass in relation to value in automobile
design is an essential part of reducing transportation's energy consumption.
Significantly smaller and lighter cars, both electric and conventionally powered, are
normally envisioned as cheap, underpowered, and unsafe vehicles that have little appeal.
Once this premise is accepted, vehicle attributes consistent with the vision naturally
emerge and an outline of market potential, profitability, and even vehicle styling and
safety then follows suit according to the core idea. These details can quickly change when
the vehicle and the market are seen from a different perspective.
By adopting a new perspective on automobile design, new marketing opportunities and new
product ideas can begin to take shape. By emphasizing innovative safety features, visually
impressive driver information systems, advanced vehicle control and crash avoidance
systems, and attractive vehicle layouts and styling, smaller urban cars and commuter cars
can emerge as safe, marketable, and even superior, transportation products. Innovative
product packaging and marketing appeals are essential for a successful transition to
electric urban cars and fuel-efficient commuter cars.
Despite today's "green" orientation, sacrifice and conservation are not
especially marketable attributes. New vehicle types must satisfy consumers' complex
psychological needs while appealing to their broad social concerns. Energy conservation
and environmental protection must be positioned as an upscale product attribute, rather
than as a necessary sacrifice in the name of economic and environmental health. Energy
conservation and emissions reduction are not primary consumer benefits. When manufacturers
address environmental concerns with attractive new vehicle themes that satisfy consumers'
psychological needs, a marketable new category of products will have emerged, and
passenger-travel energy consumption could be reduced by nearly two-thirds.
A Sustainable Paradigm for a Fully Industrialized World:
Alternative cars alone will not create a system for long-term sustainability with the
expected populations. Although transportation will be tomorrow's largest single energy
consumer (as much as 40% in the long term), combined industrial and residential needs will
account for a larger portion of society's total energy needs.
Future generations will probably have to adapt to more expensive energy, and use the
world's resources more prudently. This does not necessarily point to a world of stifling
scarcity, but more to a new sense of responsibility, and a new paradigm for product design
and the lifestyles that interrelate to form the overall production/consumption/pollution
matrix. Changes in attitudes and behavior patterns can have an enormous impact on the cost
to the ecosystem in resources and pollution. Population control and new business and
social structures are essential; and new technologies are needed as well.
Today's developed economies, which account for only one-fourth of the world's
inhabitants, have been fortunate to have abundant and cheap fossil energy supplies to fuel
their transition into an industrialized world. In a sense, today's developed societies are
similar to yesterday's pioneers, blazing the technology trail to a new frontier of
sufficiency and sustainablity for the world's future community of developed nations.
Abundant and clean energy from nuclear fusion, along with fuel cell cars and
rapid-recharging, extended-range, battery-electric cars, are probably the best hopes for
meeting long-term transportation and energy needs. And new frontiers must be pioneered in
attitudes and values, which ultimately convert to resource consumption and environmental
degradation as they guide behavior. Just as alternative cars do not necessarily imply dull
product design or reduced transportation quality, new values and social structures do not
necessarily imply compromised lifestyles.