So far the gasoline engine has dominated road transportation, and many in the oil and gas industry think its role remains secure. Yet it is difficult to discount the arguments of proponents of alternative fuels, who see the flowering of cleaner motor fuels as inevitable.
A number of factors are likely to affect the future of the automobile and therefore future fuel requirements.
Among these are the potential for further combustion engine development, increasing concerns over pollution, oil and gas supply and demand, and anticipated developments in alternative fuels technologies.
Although forecasters avoid specific forecasts of fuel requirements, preferring instead to talk in terms of scenarios, they generally agree the outlook for fuel requirements can be split into three periods:
- At least 30 years in which gasoline remains clearly the supreme fuel, although alternative fuels become increasingly competitive.
- A crunch period estimated to occur in 2025-2030 in which one or more alternative fuels may become as viable as gasoline and diesel.
- A period of decline for gasoline and diesel fuel and ascent for one or more alternatives, although which alternatives are most promising is open to debate.
While this three period approach is a sketch of current thinking, there is a strong lobby within the oil industry that reckons there is enough potential left with combustion engines to rule out wide use of alternatives until the world's oil reserves run out.
FUEL DEMAND
The World Energy Council (WEC) says transport is the fastest growing sector for energy demand and has been virtually the only growth area for oil demand during the past 20 years.
WEC figures show some countries in the Organisation for Economic Cooperation & Development (OECD) have almost 600 cars/1,000 people, while most non-OECD countries average less than 20 cars/1,000 people.
"This suggests an enormous potential for road transport expansion and an associated increase in energy consumption and transport infrastructure," said WEC in a draft report being prepared for publication this year.
WEC's report looks as far ahead as 2020. It foresees interest in the problem of global warming restricted to OECD countries, while non-OECD countries will concentrate on their own problems.
The study is based on three scenarios: Green Shock, under which growth in transport sector energy demand is halted abruptly; Muddling Through; and Markets Rule, in which energy demand for transport grows by 175%.
WEC says a common trend in the scenarios is diminishing importance of cars in comparison with trucks and air transportation. Cars are expected to consume only 30% of transportation energy in 2020, compared with 50% today.
The number of cars expected by WEC to be on the road by 2010 varies from 1.118 billion under the Markets Rule vision to 775 million under the Green Shock outlook. Even the latter is an increase from today's figures.
Roger Booth, head of renewable energy in supply and marketing for Shell International Petroleum Co. Ltd., estimates there are now 600 million vehicles on the road worldwide.
They burn more than 600 million metric tons/year of gasoline and 370 million metric tons/year of diesel fuel. This, said Booth, equals a fuel use rate of 40,000 I./sec.
"The potential for fuel efficiency improvements is significant," says WEC, "with a 50% reduction from today's average level clearly feasible by 2020. It is thus obvious that a substantial reduction in total passenger car energy demand is within the range of possibility."
Today's fuel is burned at an efficiency of 10-30% in traditional combustion engined vehicles, Booth says. He reckons that, taking into account increasingly efficient engines and growth in world demand, there will be enough fuel to keep running combustion engine cars well beyond 2050.
And beyond 2050, there will be enough reserves of natural gas, heavy oil, oil shale, coal, and biomass fuels to serve as viable feedstocks for gasoline.
ALTERNATIVES
The World's Main Users of Alternative Motor Fuels (85078 bytes)
Booth points out there are three basic engine types: steam, which requires any fuel that will burn; compression ignition, requiring fuels with high cetane level; and spark ignition, requiring fuels with high octane level.
Booth said, "There are only four alternative fuels to gasoline for spark ignition engines, the best of which by far is liquefied petroleum gas."
After LPG comes compressed natural gas (CNG), then methanol and ethanol. "All four have higher octane numbers than motor gasoline," Booth said.
For compression ignition engines, Booth said, the only alternatives to diesel fuel are cetane fuels derived from vegetable oils such as rape seed oil.
"Vegetable oils all suffer from moderate cetane levels," Booth said. "Also, they have relatively high viscosity and high freezing points. Although they will operate as a diesel substitute, they perform significantly better if converted with methanol to esters such as rape methyl ester."
Booth said there are only three reasons to justify a change from gasoline or diesel fuel: if an alternative fuel is cheaper, if an alternative offers significantly better performance and lower emissions, or if an indigenous alternative fuel can be used instead of imported oil.
"Bulk LPG is cheaper than gasoline," Booth said, "but vehicles need to be converted. For big fleets in cities, LPG has some environmental advantage over gasoline and diesel."
CNG has the advantage of established natural gas networks in many countries. In Italy and New Zealand, for example, drivers buy compressors so they can charge their fuel tanks overnight or use public compressor stations.
Booth said, "CNG is used commercially, but there is a need for further investment in infrastructure. Again, CNG is a good fuel for urban vehicle fleets such as buses and taxis."
In countries where there are large underused reserves of natural gas, CNG would be a more cost effective way to use the gas for transport fuel rather than converting to methanol.
Methanol fuel is about 20% more expensive than gasoline or diesel, Booth reckons.
"But there are problems with methanol. It is highly toxic and can be absorbed through the skin. And it is 100% miscible with water, so a spill into water would present a serious hazard to aquatic life."
Fuels based on vegetable oil are four or five times more expensive than gasoline and diesel, Booth says, and they have little or no comparable environmental benefit.
"They are being pushed by the agricultural lobby," Booth said. "But if you want to use surplus agricultural land for energy, it is better to grow crops for electricity generation."
Booth said it is 18 times more cost effective to grow coppiced wood as a fuel for power generation than it is to grow rape seed for rape methyl ester fuel.
DOE STUDY
The U.S. Department of Energy has completed one part of a study on the feasibility of alternative fuels. Among its aims was assessment of the Ion term feasibility of alternative fuels and in particular the chances of alternatives accounting for at least 10% of fuel used by 2000 and at least 30% of fuel used by 2010.
A DOE official said the report will not be a prediction of market conditions but an analysis of market behavior, given a set of assumptions about future market conditions.
The study presupposes that alternative fuels and vehicles have made the transition to economic and technical viability and widespread availability, said the official,"...but we have little idea of what it will take to get there."
Results so far indicate that for 2000, the aim of 10% displacement of conventional and reformulated gasoline appears feasible under existing practices and government policies.
The 2010 goal of 30% displacement also appears feasible, DOE says, given a fully established refueling infrastructure and widespread vehicle availability in that year.
"Our analysis suggests the market would sustain this level of alternative fuel use without continuous policy support," DOE said.
DOE is studying the likely nature and costs of transition to its 2010 scenario of widespread alternative fuels and vehicles. A draft report on the 2000-2010 analysis is expected in March. Preliminary results of the transition analysis will be completed late this year.
POLLUTION FOCUS
The U.S. and European countries are pushing for reduced pollution from road vehicles, but the two regions are pushing in slightly different directions.
The U.S. is targeting urban air quality through mandatory cleaner fuels legislation, while Europe is looking at a broader picture that covers urban pollutants and global pollutants such as carbon dioxide.
Europe is seeking the best balance in various environmental tradeoffs through collaboration among the oil and auto industries and lawmakers.
"U.S. reformulated gasoline legislation is driven by ozone and carbon monoxide air issues," said Andrew Harrison, fuels development manager for Shell U.K. Ltd. "Europe is also driven by clean air issues, but they are different and less acute than in the U.S. and may require different solutions."
Air quality problems in U.S. cities are typically worse than those in Europe, Harrison said. There are many cities in the U.S. classed as carbon monoxide nonattainment areas, whereas in the U.K., for example, CO levels are not considered a serious problem.
Europe's approach is the tripartite Initiative, which includes a $12 million research program in pursuit of lasting air quality improvements.
At the time of the program's launch, Harrison said dramatic reductions in traffic emissions can be expected by 2010 despite a predicted growth in traffic (OGJ, Nov. 7, 1994, p. 40).
But beyond 2000, Harrison warns, the easy technological solutions will have been implemented. From then on, progress will be driven by specific air quality targets and their implementation costs.
"Europe is following behind the U.S. and building on what has been learned there to identify what is best for Europe," Harrison said. "The reformulated gasoline 'solution' appropriate to the U.S. will almost certainly not be appropriate for Europe."
European fuels have already been reformulated to reduce emissions, he said, as is shown by the move to unleaded gasoline, reductions in vapor pressure, and lower sulfur levels in diesel fuel. "Reformulation is only another way of specifying gasoline, however. There is no magic formula."
Harrison sees further control of fuel composition as only one of a number of options for reducing emissions.
"However," he said, "changes to fuel composition can be very expensive and involve major capital investment. It is vital that we identify the most cost effective means of meeting our air quality objectives."
The European Petroleum Industry Association (Europia) said much of Europe's changes to fuel and engine systems has been driven by continuing tightening of vehicle exhaust limits.
"By the time the next change becomes effective in 1996," Europia said, "these limits will have been reduced six times since first introduced in 1970.
"Dramatic though overall improvement by 2000 will be, each new change has contributed less and the cost of implementing the technology necessary to cope with increasingly stringent requirements has increased dramatically."
A European Commission program of air quality modeling, known as the Auto-Oil program, is being coordinated by the joint Research Institute at Ispra, Italy.
Europia said, "This work will quantify what additional improvements may still be needed to attain agreed air standards. The Auto-Oil study will be completed in mid-1995 and will be the basis for establishing the next tranche of vehicle emissions limits for 2000."
CAR RESEARCH
"This close collaboration will become even more important if we are to continue to satisfy customers' needs for mobility and society's environmental needs at the same time."
In September 1993, the three U.S. auto giants-Ford, General Motors, and Chrysler-decided to collaborate under a program called the Partnership for a New Generation of Vehicles (PNGV).
PNGV research aims to develop a tripled efficiency "clean car" within a decade. Amory B. Lovins, research director at Rocky Mountain Institute (RMI), Denver, wrote in January's Atlantic Weekly magazine that this project aims to create a leapfrog mentality.
"The fuel efficiency of cars has been stagnant for the past decade," Lovins said. "Yet the seemingly ambitious goal of tripling it in the next decade can be far surpassed.
"Well before 2003, competition, not government mandates, may bring to market cars efficient enough to carry a family coast to coast on one tank of fuel, more safely and comfortably than they can travel now, and more cleanly than they would with a battery-electric car plus the power plants needed to charge it."
Lovins reckons automakers add new gadgets to cars each year to compensate a little more each time for the inherent inefficiencies in powering "steel behemoths." He said, "We need to design cars less like tanks and more like airplanes. When we do, magical things start to happen, thanks to the basic physics of cars."
HYPERCAR
Lovins and his RMI colleagues are working to develop Hypercar, which incorporates new thinking in propulsion and materials in an ultralight, hybrid engined design.
"Adding hybrid-electric drive to an ordinary car increases its efficiency by about a third to a half," Lovins wrote. "Making an ordinary car ultralight but not hybrid approximately doubles its efficiency. Doing both can boost a car's efficiency about tenfold."
Hypercar's wheels are driven by small electric motors, which in turn are fueled by burning "any convenient fuel" in a 10-20 hp engine, fuel cell, gas turbine, or other power plant.
Hypercar's body would be a molded monocoque structure made from materials combining plastics with embedded fibers such as carbon and glass.
RMI reckons the Hypercar will weigh only 900 lb and will use 5-20 times less fuel and emit 100-1,000 times less pollution than conventional steel bodied cars powered by an internal combustion engine.
Lovins believes all the key technologies needed to make Hypercars are in place. They need only to be properly combined, he says.
RMI cites these examples of progress in projects similar to Hypercar:
- A General Motors concept car built in 1991 that achieved 62 mpg using a conventional combustion engine and mechanical drive train.
- A Western Washington University student project in which a two seater hybrid car achieved 202 mpg last April in a test by DOE.
- A four seat light hybrid auto built by Swiss design firm Esoro that achieved the equivalent of 150 mpg in October 1994 despite 500 lb of batteries needed to provide a 60-70 mile combustion free range.
- Prototype composite delivery vans made by a Florida firm that weigh less laden than conventional steel vans weigh empty.
- An ultralight hybrid train designed by an Idaho inventor, which is said to cost 5-10 times less than existing hybrid trains.
Although none of these is the same as the Hypercar concept, RMI says they have enough common elements to support the practicality and performance of Hypercar. RMI believes Hypercars could reach the U.S. market as early as 1998.
RMI said, "The technologies already exist, the prototyping and tooling are faster than for today's cars, and there is a strong incentive to bring Hypercars to market before others do."
DOE last November unveiled a natural gas vehicle said to have a driving range of 300 miles between fuel stops, trunk space only 25% less than that of a conventional car, and performance as good as a gasoline equivalent.
The Advanced Natural Gas Vehicle (ANGV) was developed by Johns Hopkins University Applied Physics Laboratory, Laurel, Md. It is a converted Geo Prism car, which DOE said would cost $2,000-3,000 more on the road than a standard model if the ANGV were mass produced.
CRUNCH
The expected crunch period, in which gasoline and diesel fuels are matched in viability by one or more alternative fuels, could be caused by one or more of a number of issues, said Shell U.K.'s Harrison.
First on his list is environmental concerns. But he is not certain emissions issues will cause a crunch because he believes gasoline and diesel can be made competitively clean burning.
Fuel supplies are another potential crunch cause, but Harrison said supply is not expected to be a key issue for another 40 years.
And there is politics, which Harrison said already has shown significant effects, particularly in the U.S., where agriculture derived oxygenates have been mandated, and France, where vegetable derived components have been encouraged by tax incentives.
Harrison points out that fuel economy plays a major role in reducing carbon dioxide emissions. Reduced car weights and novel design concepts such as hybrid power systems and braking energy recovery could yield vast improvements in fuel mileage.
"There is more to fuel economy than technical advances," Harrison said. "There are plenty of ways fuel economy can be improved without technical change, such as purchase of smaller, less powerful cars. This, however, is not what customers want. The trends are exactly the opposite."
WEC expects average fuel efficiency of road vehicles to double by 2020, leading to a consumption of 5 I./100 km for cars in OECD Europe and Japan.
"Fuel efficiency in the U.S. and the developing world is expected to remain lower," WEC said, " due to the larger size of American cars and generally poor road conditions in the developing world."
One factor that may bring increased pressure on use of gasoline and diesel fuels is a growing political perception of what should be done about global warming. Booth reckons the pressure to reduce emissions could increase early in the next century.
"Then improved efficiency of combustion engines will be the most effective way to reduce emissions," Booth said. "If you compare cars of 1955 with those of today, think what the cars of 2035 will be like if we make the same level of changes again."
Booth sees cooperation with engine and automakers as crucial to further evolution in road transport: "There is no point making a fuel for a car that will not exist."
Worldwatch Institute, a Washington, D.C., energy think tank, believes natural gas and electricity will become the next generation of transportation fuels.
They will take off after the next decade, said Christopher Flavin, Worldwatch vice-president of research, because they are very clean on a life cycle comparison basis and have an infrastructure for distribution.
Flavin foresees Southeast Asian developing countries taking a lead in natural gas transportation because they will have booming economies, indigenous natural gas reserves, and will be building fueling networks largely from scratch.
"You can argue that for countries starting out today, it will take less effort to build infrastructure for alternative fuels," Flavin said.
Electric vehicles, Flavin argues, constitute a fundamental change in automotive technology with undeniable benefits for urban transport.
He warns against statistics that compare emissions from gasoline engines with those from electric vehicles for which it is assumed coal fired power generation is the ultimate source.
"Electricity is increasingly generated using gas fired plants," Flavin said. "There is no question that electric vehicles coupled with gas fired electricity generation is cleaner than even the best gasoline engine."
THE LONG VIEW
Hybrids, including hydrogen fuel cells, are technologies Booth sees dominating research into long term transportation needs.
However, there are major roadblocks to development of hydrogen fuel cell solutions. First is storage. Booth said with current storage methods only about 3% of the total weight of the fuel store is hydrogen. The rest is container.
A high efficiency fuel cell must have a relatively light load, Booth says, which means a larger, heavier cell.
And then there is safety. Booth is concerned about a highly explosive gas being used by the public.
He suggests it is too early to write off the combustion engine in comparison with fuel cell hybrid vehicles.
Hybrid vehicle designs with optimized combustion engines, combined with lighter vehicles and energy storage, are yielding better than 28% efficiency, Booth said.
A combustion engine auto with energy storage such as a high speed flywheel and regenerative braking is ultimately capable of 40% energy efficiency, Booth figures. No new network would be required for fueling,
A hydrogen fuel cell hybrid vehicle could be 50% efficient, Booth says, but widespread use would require a new fueling network.
"In the latter part of the 21st century, when gasoline and diesel fuels will be higher in cost, alternative fuels will become viable," Booth said.
"The steps toward very low emissions will be small because there is a large transportation system involved. The process will be evolution, not revolution. But looking back after 40 years it may seem like a revolution."
A 1993 report by the International Energy Agency (IEA) concluded that recent electric vehicles had achieved ranges of 100-250 km and top speeds of more than 100 km/hour.
"The attractiveness and market penetration of electric vehicles will improve as consumers learn more about these vehicles and as their technology advances and prices fall," IEA said.
"Other contributing factors will be sharper awareness among vehicle users that range is less crucial than imagined and that, in fact, every vehicle does not need to serve every driving purpose."
Flavin believes hydrogen is the ultimate fuel for the distant future, although storage problems of such a light molecule will have to be solved.
Flavin said he recently came across the idea of using ammonia as a fuel, a concept he described as "...the favorite among my wild cards" for future transportation.
"If you think of the ammonia molecule as a hydrogen carrier, the idea makes sense. Ammonia would be a carbon-free fuel, it can be carried by pipeline, and it already has a very substantial infrastructure."
Ammonia is the most common nitrogen fertilizer, hence the large amount of storage currently devoted to its use.
The U.S. Army is said to have tested ammonia for fuel use in the 1960s, although the experiment was abandoned. Now Johns Hopkins University is studying an ammonia fueled car.
Reverting to more developed alternative concepts, Flavin said the hybrid car, with wheels driven by electric motors, is the most likely development.
"I'm willing to bet big money that in 20 years most cars will have some sort of electric drive," Flavin said. "If you step back from energy industry politics, it seems to be the most logical way to go."
Copyright 1995 Oil & Gas Journal. All Rights Reserved.
