Electric/Hybrid-Electric/Hydrogen Capsule Summary
No easy alternatives to the internal combustion engine
Toyota Foresees Combinations of Advanced Technologies In Future Cars
With more than 1 billion cars expected to be on the road by 2020, a top Toyota engineer says advanced technologies are needed for the automobile to remain an effective means of transportation.
Hiroyuki Watanabe, managing director and a member of the board for Toyota Motor Corporation (TMC), told the Society of Automotive Engineers' 2000 Future Car Congress that the concern is not only in developing new technologies, but also improving technologies that already exist.
"I believe that the opinion that the end of the internal combustion engine era will come, and that it will be replaced by the fuel cell era, and that hybrids will be used as an interim measure, is not correct," said Watanabe, who is responsible for hybrid and fuel cell development for TMC. "Rather, I believe that there will be a time when various engines and power sources will exist simultaneously."
Watanabe believes that in order for an environmentally-friendly vehicle to have a genuine impact on the automotive world and society, it needs to be accepted by consumers. In order for this to happen, the vehicle must be user-friendly, use a fuel that is readily available and be sold at an affordable price. He stated that consumers should not have to put up with reduced performance in return for environmentally-friendly automobiles. "It is our firm belief that the hybrid vehicle offers many benefits to consumers and will become the turning point in environmentally conscious technology for the future," continued Watanabe.
According to Watanabe, one vehicle that meets these criteria is the Toyota Prius hybrid, a roomy, five-passenger family sedan that will go on sale in the U.S. this summer. The Prius is the world's first mass-produced gasoline/electric hybrid vehicle powered by both a conventional four-cylinder engine and a clean, quiet electric motor. The Japan-market Prius has sold more than 34,000 units since December 1997. In contrast, the number of pure-electric vehicles sold worldwide since their introduction has reached just under 30,000 units, but has taken 30 years to achieve.
Watanabe sees potential in another type of hybrid, the Fuel Cell Hybrid Vehicle. He expects that in the future, there will be new energy storage technology and new drive system technology that will foster a variety of new hybrids. An important challenge to future hybrid advancements is worldwide commonality and compatibility of fuel choice. "It will require the teamwork of manufacturers, government and industry to determine a standard for both fuel and infrastructure," Watanabe said.
Watanabe stated that excessive emissions of CO2 is a global problem that must be addressed by all industries. Watanabe believes that Toyota understands the importance of developing new technologies, but at the same time recognizes the need to work within an existing infrastructure that does not readily support the use of alternative fuels.
"At Toyota, we firmly believe that there is more than one answer to the issue of personal transport systems for the 21st century," ," said Watanabe. "Toyota is committed to making a true impact on a global scale to eco-projects, and to contributing to the sustainability of the automotive world."
Electricity and hydrogen are the two cleanest sources of power available, and can reduce emissions of all air pollutants by 75-100%, depending on the manner in which they are generated. However, the technology to store and use these energy sources on board vehicles is limited in capacity and is presently significantly more expensive than gasoline or diesel technology. With the possible exception of certain short- or medium-range hybrid electric vehicles, whose air quality impacts depend on the fuel used in the auxiliary power unit, vehicles powered by electricity or hydrogen are not projected to be significant in the context of the ICTC.
Executive Summary
Electric and hybrid electric propulsion systems are beginning to move from prototype vehicles to production vehicles in a number of market niches. For example, battery-powered electric buses have been in use in Santa Barbara, California and Chattanooga, Tennessee for over five years now, and electric passenger cars will be launched into the U.S. marketplace later this year by the major U.S. manufacturers. In fact, electric propulsion systems were originally the most prevalent in the first decades of the automotive age.
Electric vehicles suffer from the current limitations of energy storage technology. Batteries, the current state of the art, are heavy and slow to refuel (without special high-current equipment). The low production volumes to date have also made electric vehicles expensive, in some cases almost twice the price of a comparable gasoline- or diesel-powered vehicle. Consequently, electric vehicles are initially expected to best suited for short-range light duty applications, such as commuter cars or postal fleets.
Hybrid electric vehicles offer significant performance improvements over electric vehicles, because of the extended range and continuous battery charging that the hybrid auxiliary power unit offers. However, because of the auxiliary power unit, hybrid vehicles create more air pollution than do electric vehicles, in quantities directly related to the type of fuel used. A number of hybrid electric vehicle development projects are underway, which may result in short- to medium-range hybrid electric class 6, 7, or 8 trucks being introduced commercially by the turn of the century.
Finally, hydrogen propulsion is considered by many observers to be the next paradigm for transportation in the 21st century. Whether used in electrochemical fuel cells or burned in an engine, hydrogen produces either very low emissions or no emissions at all. However, hydrogen-powered internal combustion engines are still in the development stages and fuel cells are currently still too expensive for any but the highest value transportation market niches. The infrastructure issues also associated with this fuel make it unlikely that hydrogen power will be viable for heavy-duty vehicle applications until many years into the next century.
General Description and Status as a Vehicle Fuel
Electricity has been used for decades as a vehicle fuel, and in fact, was the predominant form of propulsion for automobiles in the early years of this century, being eclipsed by petroleum fuel only once the automatic starter was introduced. Electricity can be provided to a vehicle either via direct connection to the vehicle (such as overhead catenaries, third rails or even in-roadway inductive systems) or via on-board storage (batteries) or energy conversion devices (motor generators, fuel cells, etc.)
Examples of electrical propulsion using direct vehicle connections include railways in Europe; the world's major urban subway systems; electric trolley buses in San Francisco, Seattle, and elsewhere; and other similar applications. Examples of battery-powered electrical propulsion include plant and industrial vehicles, such as courtesy carts in airports, electric forklifts and small trucks; golf cars; shuttle and transit buses in Santa Barbara, California, Chattanooga, Tennessee, and other locations; and fleets of passenger cars and light-duty trucks being operated by utilities in the U.S., Europe and Japan. Examples of vehicles powered by electricity delivered by energy conversion devices include diesel-electric locomotives (the predominant form of railroad propulsion in the U.S.); and hybrid-electric buses now being tested in California, Illinois, New York, Germany and Japan. The auxiliary power units on these hybrid electric buses use a variety of fuels, including compressed natural gas, gasoline or diesel fuel used in internal combustion engines; and hydrogen used in a fuel cell. Fuel cells are electrochemical devices which combine hydrogen and oxygen in a non-combustive chemical reaction to produce electricity and water. This white paper will only examine battery-powered electric vehicles and hybrid-electric vehicles.
Electric vehicles are extremely clean, producing no emissions of air pollutants from the vehicle. Even when the emissions from the electricity generating stations are considered, electric vehicles are still significantly cleaner than gasoline- or diesel-powered vehicles. Recent studies have shown that the mix of electric power generation stations that would supply battery-powered vehicles in California are over 90% cleaner than gasoline- or diesel-powered vehicles. Even in locations with higher proportions of coal-fired power plants, such as the Northeastern U.S., battery-powered electric vehicles have been shown to be over 70% cleaner than gasoline- or diesel-powered vehicles.
Hybrid-electric vehicles are only as clean as the source of energy for the on-board energy conversion device. Those vehicles powered by natural gas can be very clean, ranging from "zero-emission vehicle equivalent" levels of air pollutant emissions from gas turbines with catalytic combustors, to reciprocating engines which have been optimized to produce on the order of 1.5 grams of nitrogen oxides (NOx) per brake horsepower-hour and essentially no emissions of non-methane organic gases (NMOG). Propane-powered vehicles have also been demonstrated to be significantly cleaner than gasoline- or diesel-powered vehicles, and similar results would be expected from propane-powered hybrid-electric vehicles.
Fuel cell-powered vehicles are also essentially emissions-free. Those fuel cell-powered vehicles which used bottled hydrogen produce no air pollutant emissions, generating only water as a by-product. Fuel cells can also be powered by methanol or natural gas, which are converted to hydrogen in on-board reformers. Vehicles powered by these fuel cells do produce emissions of NOx and carbon monoxide, although at levels substantially below gasoline- or diesel-powered vehicles. A final category of hydrogen power is direct combustion of hydrogen, usually in a reciprocating spark-ignited engine. These engines, when coupled either directly to the transmission of a vehicle or when used to generate power for an electric drive train, are also extremely low emission, producing primarily NOx.
Engine and Vehicle Technology Issues and Commercialization Status
DC motors and controllers are available from a variety of manufacturers in a variety of sizes, and a number of different types are currently in use in transportation applications from locomotives to golf cars. AC motors produce better performance, providing higher power over a broader range of speeds than DC motors (thereby eliminating the need for multiple-geared transmissions in certain applications). However, AC motors are more expensive and have been limited to date to applications where power requirements are higher and the differential cost is not a significant issue. A number of suppliers, including Delco Electronics, Northrup-Grumman, Indramat and others, have begun to develop lower-cost AC drive systems, aided primarily by the continuing cost reductions in power electronics. These drive systems are being developed for passenger cars, light trucks and buses, although the larger-size systems would also be applicable to class 6,7, and 8 trucks - running the gamut from local delivery vehicles to long-distance tractor-trailer combinations.
Energy storage devices are a critical component for electric and hybrid-electric vehicles, and their development into commercially-viable transportation systems has been slow. Most battery-powered vehicles on the road today use lead-acid batteries, which have good power density (related to acceleration performance), but suffer from low energy densities (related to vehicle range) - on the order of 30-45 wH/kg - and usually only last 300-500 charging cycles (1-2 years of daily use). Depending on the size of the battery pack and the charging power level used, lead-acid batteries require from 3 to 15 hours to completely recharge. As a result, lead-acid battery-powered vehicles are used primarily for applications that do not require daily driving ranges greater than 30-50 miles. In some cases, vehicles are designed to accommodate battery packs which can be removed and replaced quickly, thereby giving an operating range limited only by the number of completely-charged battery packs available.
Nickel-cadmium batteries are also currently in use in transportation applications, and they provide almost double the range and life of lead-acid batteries. Unfortunately, nickel cadmium batteries are also at least twice as expensive as lead-acid batteries, creating problems for organizations interested in electric-powered transportation, but who also have capital investment limitations (such as transit districts). However, battery producers such as SAFT and Acme have stated that increased production levels will drive the price of nickel cadmium batteries down, and that they would be interested in participating in battery leasing programs, to reduce the initial costs for users.
Other energy storage alternatives are being developed, including advanced batteries, such as nickel metal hydride, sodium nickel chloride, lithium ion and zinc-air. These batteries are currently in research or prototype phases and are a number of years away from commercialization. Some vehicles are available with nickel metal hydride batteries, such as Solectria Corporation's Force, an electric conversion of the Geo Metro model, but the battery pack is very expensive for this vehicle. Flywheel energy storage systems and ultracapacitors are also under development for use as power augmentation devices, but these systems are not expected to be commercially available until the early years of the next century. There are buses in Germany which use low-speed metal rotor flywheels and hybrid-electric refuse trucks using flywheels for power augmentation are planned for Tokyo during the next couple of years, but composite-rotor flywheels are still in the early stages of development for transportation applications.
As for auxiliary power units, a number of engine/generator combinations are currently available from various manufacturers, including Onan, Hercules, Cummins, and Fisher. Turbogenerators are under development by Allison, Allied-Signal and Capstone Turbine, in sizes ranging from 24 to 50 kW. These auxiliary power units can operate on various fuels, ranging from diesel to hydrogen, with corresponding emissions characteristics. Engines that burn pure hydrogen have not been developed by major manufacturers, however, some conversions of gasoline- or natural gas-powered engines have been completed and are in demonstration programs in various locations.
The selection of electric, hybrid-electric and hydrogen-powered vehicles is currently quite limited. Electric passenger cars and pickup trucks are available from Solectria and B.A.T., and General Motors, Ford and Chrysler will all be introducing electric vehicles in the western U.S. in late 1996 and early 1997. Electric buses are available from APS Systems, Inc., Blue Bird, AVS and U.S. Electricar, and a number of bus manufacturers are developing hybrid-electric versions (including Gillig, Orion, El Dorado National, and others). Prototype fuel cell-powered buses have been developed by Ballard Power Systems and by the U.S. Department of Energy, but no commercial versions are available. No local delivery or long-distance trucks are currently available in electric or hybrid-electric versions, although Volvo and Freightliner are pursuing the development of hybrid-electric trucks in classes 6-8.
Availability of Electricity and Hydrogen as a Motor Fuel
The electricity supply infrastructure is probably the most ubiquitous of all transportation energy sources, being available in a number of different power levels almost anywhere there is human population. The suppliers have traditionally been the regulated utility companies, although with the development of low-cost distributed power units and with restructuring activities proceeding in the utility industry, electrical power may be available from a variety of new sources in the near future. Electric power is relatively inexpensive, and recent studies of fueling costs show that gasoline and diesel are approximately twice as expensive as electricity as a transportation fuel.
Hydrogen is not widely available, on the other hand. The most cost-effective means of producing hydrogen currently is steam reformation of natural gas, requiring a significant investment in capital facilities. Because of its use in the petroleum refining process, hydrogen is available in larger quantities near refineries, and can be obtained from industrial gas suppliers. Hydrogen is not easily stored or transported, because of its highly reactive nature (which causes accelerated fatigue in metal storage and transportation equipment). Hydrogen is typically supplied as a compressed gas, with handling characteristics similar to natural gas.
Key Stakeholders in Commercializing Electricity and Hydrogen as Motor Fuels
Some Pluses and Minuses of Electricity and Hydrogen as Motor Fuels
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Strategic Opportunities
Strategic Threats
Suggested Key Elements of a Commercialization Strategy for Electric, Hybrid-Electric and Hydrogen Power
No easy alternatives to the internal combustion engine
by Joseph L. Bast
As Vice President and Presidential candidate Al Gore was reiterating his controversial call for "phasing out" the internal combustion engine in less than 25 years, the Energy Information Administration, a department of the Administration's Department of Energy, was saying it couldn't be done.
Skepticism about how fast viable alternatives to the internal combustion engine could emerge was a central theme of a presentation by David M. Chien, a senior transportation and forecasting analyst for the Energy Information Administration, at the EIA's Annual Energy Outlook Conference held in Washington DC in March.
Chien predicted that fewer than one million of the seven million cars expected to be sold in the year 2020, about 10 percent, will have something other than a conventional internal combustion engine under its hood.
With some 200 million cars currently on the roads in the U.S., it will take decades before the existing fleet turns over and more than a small fraction of cars on the road are powered by something other than conventional gasoline and diesel engines.
Candidates to replace the ICE
Three propulsion technologies currently lead the competition to replace the internal combustion engine, or ICE. They are:
- Hybrids: A small ICE, probably fueled by gasoline, diesel, or natural gas, is paired with an electric motor that is recharged by the energy used in braking. The electric engine assists the main power plant when additional speed or acceleration is needed. Toyota and Honda both sell small gasoline-electric cars in the U.S., and Ford has said it will begin making a family-sized hybrid electric vehicle by 2003.
- Fuel Cells: Fuel cells generate electricity by combining hydrogen and oxygen electrochemically, without combustion. The absence of a national infrastructure for providing hydrogen to motorists means most fuel cell vehicles will have to "reform" hydrogen from gasoline or methanol using an on-board device. Some technological barriers remain to be solved, such as finding ways to reduce the size and weight of the device that "reforms" the traditional fuel or a way to safely store hydrogen on-board at room temperature.
- Electric: Electric motors are powered by on-board batteries that are charged at night or when the vehicle is not in use. Electric cars themselves produce zero emissions, but their production is not zero-emission. Carbon dioxide and sulfur are produced by centralized electric generation plants, and lead is released during the production and handling of batteries. Electric cars are now widely thought to be an inferior option due to their short range, high cost, and limited performance. Detroit will build them only to meet the zero-emission requirements of a few states such as California and Massachusetts.
Advantages of ICE
The perseverance of ICEs and conventional fuels predicted by Chien won't be due to inertia or "foot-dragging" by car and truck manufacturers. Rather, current automotive technologies hold several advantages over their competitors.
First is low purchase price. EIA's Chien expects hybrids to cost between $10,000 and $15,000 more than conventional cars, in constant 1998 dollars, from the time of their introduction around 2003 through 2020.
Fuel-cell powered vehicles are expected to cost between $45,000 and $65,000 more than conventional cars when they become available in 2005. However, Chien forecasts the price of fuel-cell cars will gradually fall until they are "only" about $15,000 more in 2020. Chien did not forecast the prices of electric cars, probably because of barriers to commercial production described above.
The second advantage of ICEs is their low cost of operation: With inexpensive gasoline and diesel readily available, owners of cars with conventional internal combustion engines enjoy operating costs of only $0.05 per mile and have no difficulty finding fuel. Hybrids are expected to have an advantage over ICEs due to their superior fuel economy, but fuel cells and electric cars will be at a decided disadvantage.
Chien forecasts that the number of refueling stations offering hydrogen or methanol will be just over 2 percent of the number of stations offering gasoline and diesel in the year 2011, and only 3.5 percent by 2020.
A third consideration is vehicle range. A typical new car with a gasoline ICE has a range between refuelings of approximately 345 miles. If modified to reduce weight, rolling resistance, etc., such a car can go 545 miles before refueling. Electric cars can't approach either range, and barring an unexpected breakthrough in battery technology, it is unlikely they ever will.
Down-weighted fuel-cell cars with hydrogen stored on-board have ranges of 402 miles, comparable to current cars but about one-third less than a similarly down-weighted conventional car. Fuel-cell cars that "reform" hydrogen from gasoline do better (845 miles), and hybrids do best of all (1,090 miles).
A fourth problem for technologies seeking to upset the internal combustion engine is that American drivers consistently demand higher performance from new vehicles, about 3.5 percent more horsepower per year, according to Chien. Electric cars are competitive in this regard . . . for about one hour. Quick starts and high speeds quickly sap the power from the batteries of electric cars, greatly reducing their range.
The promoters of hybrids and fuel-cell cars believe they can deliver performance that is comparable to that of traditional internal combustion engines, but so far hybrids (such as Honda's new Insight) rely on down-weighting and other tricks to achieve parity--changes that conventionally powered cars are likely also to adopt in the coming years. Scientists and engineers are still searching for ways to downsize and lighten fuel cells and fuel "reformers."
A final consideration is safety. In the event of an accident, acid-filled batteries may leak and pressurized canisters of hydrogen may explode. Recharging batteries and refilling pressurized tanks present significant safety risks that few people are now accustomed to managing. The extensive down-weighting proposed to offset the added weight of fuel cells and batteries makes those vehicles less safe in a collision with other cars or stationary objects.
At a time when many new car buyers choose large sport utility vehicles because of their perceived superior safety, it is not unrealistic to imagine that a large share of the buying public will take a pass on electric and fuel-cell vehicles for this reason alone.
Lessons for environmentalists
The slow rate of introduction for alternatives to the conventional internal combustion engine shows that solving the technological challenges of new engine designs and fuels is not the primary difficulty they face. More important is producing a product with features that consumers are known to prefer, such as safety and performance.
Conventional engine and fuel technologies are moving targets, in the sense that they are continuously being improved at rates that probably approach the rate of improvement being reported by alternative technologies. Emissions from new cars in the year 2005 will probably be so low that the even-lower emissions of hybrids and fuel-cell cars won't be a selling point.
Today's cars and trucks produce consumer benefits often overlooked by their critics and those who think finding substitutes will be easy. A customer-oriented approach to automobility begins by asking drivers what they want, not what the latest technology can deliver.
Too many environmentalists and government regulators ignore revealed customer preferences, and then wonder why Detroit "drags its feet" when it comes to commercializing new technologies.
Joseph L. Bast is president of The Heartland Institute, publishers of Environment & Climate News, and coauthor of "The Increasing Sustainability of Cars, Trucks, and the Internal Combustion Engine," a Heartland Policy Study published on June 22, 2000.