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The National Academies Summit on America’s Energy Future: Summary of a Meeting 9 Transportation The United States currently imports about two-thirds of the petroleum that it uses. This is about the same amount of petroleum that is burned in U.S. vehicles. There is an “absolute compelling need to do more in the area of energy efficiency and energy-enhancing technology development,” said Reuben Jeffery, and improving the efficiency of vehicles will be an essential part of that task. PROSPECTS FOR IMPROVEMENT The fuel economy of the new light-duty vehicle fleet (cars, light trucks, and sport utility vehicles) has declined over the past two decades, Paul Portney observed. “We haven’t been making a lot of progress in making cars that reduce our dependence on oil overall or on imported oil.” But Portney expressed several reasons for optimism. In recent years, fuel economy standards for the light-duty truck segment of the new vehicle fleet have gone up twice. More importantly, the Energy Independence and Security Act of 2007 will require automakers to achieve an average 35 miles per gallon for new cars and light-duty trucks by the year 2020, up from about 25 miles per gallon for new cars and light trucks today. That legislation was a major achievement, Portney said, given the political climate in the United States and the many challenges facing domestic car manufacturers. Furthermore, considerable additional progress is possible. Rodney Nelson cited a recent study done by a Massachusetts Institute of Technology group which concluded that it is technically possible to double the fuel economy of
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The National Academies Summit on America’s Energy Future: Summary of a Meeting U.S. cars and light-duty trucks by 2035 (Cheah et al., 2007). “So the recent legislation went partway. It’s technically possible to go farther,” Nelson said. “It costs money, and the consumer may not necessarily jump up and down to buy one, but it’s technically possible. And it’s the biggest lever the United States has to decrease oil demand.” High gas prices are very painful to people who cannot afford them, Portney said. But high prices also have a positive effect by changing incentives, technologies, and tastes. Gasoline consumption, which had been rising for many years, has begun to decline. And a different mix of vehicles is appearing on U.S. roads. “Hybrids on the road will soon number in the millions rather than the tens or even hundreds of thousands,” Portney said. “We’ve seen the introduction into the United States on a larger scale of cleaner, much better performing diesel engines, which is a very important development in improving fuel economy. And now we’ve begun to see what I think is perhaps the most promising of the so-called conventional technologies—plug-in hybrids, which I think will change the fuel economy picture in the United States significantly.” Another positive effect of high gas prices is that venture capitalists have become much more focused on clean energy and efficient vehicles. They are investing in new battery technologies, lighter materials, and alternative fuels, among other technologies. (The role of the private sector in the energy market is discussed in Part IV.) VEHICLE TECHNOLOGIES Even beyond the projections of the MIT group, great potential exists to improve the efficiency of vehicles and reduce U.S. dependence on imported petroleum, said Amory Lovins, who emphasized the energy savings that could be realized through a wide variety of technological innovations. Indeed, the key to energy efficiency, according to Lovins, is to realize that efficiency is profitable, not costly. “It is cheaper to save fuel than to buy fuel,” Lovins said. “The climate debate should be about profits and competitive advantage. Once it is reframed in that way, any remaining resistance will melt faster than the glaciers. The biggest obstacle is the assumption that climate protection is costly. That is unexamined and clearly untrue, as many smart firms demonstrate [by] making billions of dollars substituting efficiency for fuel.” Lovins’ Rocky Mountain Institute has estimated that the efficiency of cars, trucks, and planes could be tripled with investments that would pay for themselves in 2 years, 1 year, and 4 or 5 years, respectively, if decisions were made to pursue these efficiencies. First, vehicles could be made ultra-lightweight, more efficiently powered, and “slippery,” so that they move through the air and along the road with less resistance (and often with better performance). For example, a diesel-hybrid carbon-fiber concept car from Opal can go 155 miles per hour and get 94 miles per gallon (though not at the same time). Surprisingly, the
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The National Academies Summit on America’s Energy Future: Summary of a Meeting ultra-lightweight construction does not increase mass production costs, because the costlier materials are offset by simpler automaking and a power train that is three times smaller. A major problem with a conventional car, Lovins said, is that seven-eighths of the energy it uses never gets to the wheels. It is consumed in the engine, the driveline, and accessories, as well as in idling. Half of the remaining eighth either heats the tires and road or heats the air through which the car passes. “Only the last 6 percent actually accelerates the car and then heats the brakes when you stop,” Lovins said. Furthermore, only a twentieth of the mass in a car is the person driving it. The rest is the heavy steel car. So only 0.3 percent of the fuel burned by an automobile ends up moving the driver. “This is not very gratifying after 120 years of devoted engineering effort.” Because of this inefficiency, there is enormous leverage in making cars lighter, whether through light metals or advanced polymer composites. A group at the Rocky Mountain Institute completely redesigned a midsize car that can comfortably carry five adults and has 2 cubic meters of cargo space. It weighs less than half as much as the typical car today but still can protect its passengers when run into a sport utility vehicle twice its weight or into a wall at 35 miles an hour. It gets the equivalent of 114 miles per gallon on a fuel cell or 67 miles per gallon as a hybrid with a power train like a Prius, with “quite brisk performance,” according to Lovins. The estimated sticker price is $2,500 higher than a conventional car, not because it is ultralight but because of its hybrid engine. Overall, the car is cheaper to manufacture because it has only 14 body parts, which are suspended from rings rather than built up from a tub (Figure 9.1). “This is like an airframe, not a horse and buggy,” Lovins said. Most of the body parts, which are made from a single low-pressure die set, can be lifted by hand. A steel body would have 10 or 20 times more parts, and each part would have an average of four steel-stamping die sets. The parts precisely snap together for bonding, which means the usual jigs, robots, and welders are not needed, so that manufacturing plants are much less capital intensive. With color in the mold, even paint shops are unnecessary. Lovins displayed a test piece for military helmets that was two-thirds carbon fiber and one-third carbon plastic, which was stronger than titanium. “Plastics have changed since The Graduate,” he said. Such materials can provide aerospace performance at automotives costs. Cars made of such materials are half the weight and save half the fuel. Such materials also absorb 12 times more crash energy per pound than steel, with manufacturing costs about the same as for steel. Lovins acknowledged that composite materials are not the only possible solution; metals can offer some of the same advantages. “The market will sort out which ones win.” Lovins also described a concept car developed by Toyota (Figure 9.2). It has the interior volume of a Prius but uses half as much fuel. It weighs 400 kilograms (880 pounds) as a hybrid, about one-third the weight of a Prius, or
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The National Academies Summit on America’s Energy Future: Summary of a Meeting FIGURE 9.1 Lightweight cars based on composite materials could lead to radically simplifi ed manufacturing. SOURCE: Fiberforge Corporation and Rocky Mountain Institute. FIGURE 9.2 The 1/X concept car, designed by Toyota, that weighs one-third as much as a Prius, uses half as much energy, and yet has the same interior volume. SOURCE: Toyota Motor Corporation.
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The National Academies Summit on America’s Energy Future: Summary of a Meeting 20 kilograms (44 pounds) more with batteries added to the car to make it a plug-in hybrid. “Coincidentally, [this] is exactly what I said in 1991—I think to an Academy group—that a good four-seat carbon car should weigh, to much hilarity from the industry.” Concept cars are often dismissed as bragging, Lovins said, but in this case the company Toray recently announced that it will build a ¥30 billion company to mass produce carbon-fiber autobody panels and other parts for companies like Toyota and Nissan. About the same time, Ford announced that it will reduce the weight of every platform it makes by 250 to 750 pounds starting with the 2012 model year. The following month, Nissan announced an average weight reduction of 15 percent by 2015. “Light-weighting is now the hottest strategic trend in the industry,” Lovins commented. These and other changes in the transportation sector could have a substantial impact on oil imports, Lovins said. Combined with the use of biofuels, the substitution of natural gas for oil, and the generation of hydrogen from renewable energy sources like wind, the projected consumption of oil could be cut from 28 million barrels per day in 2025 to 16 million barrels per day using technologies that are already available, he said (Figure 9.3). Cumulative carbon emissions would go down by more than a trillion tons, and the amount spent to buy petroleum would be reduced by tens of trillions of dollars. Further efficiency gains, greater use of biofuels or natural gas, or the use of hydrogen from natural gas or renewable energy sources could eliminate the need to import any petroleum. (Pathways to a sustainable energy future are described in Part IV.) Even major industries have changed quickly in the past, Lovins pointed out. The auto industry in the 1920s took just 6 years to switch from wood to FIGURE 9.3 Greater efficiency (the second bar in the above graph), combined with greater use of biofuels and natural gas, could reduce or eliminate U.S. reliance on imported petroleum. SOURCE: Rocky Mountain Institute.
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The National Academies Summit on America’s Energy Future: Summary of a Meeting steel auto bodies. At the start of World War II, it took just 6 months for the industry to switch from making cars to the tanks and planes that won the war. Boeing instituted a radically new airframe in the 787 in just 5 years. A small team at General Motors took a battery-powered car from launch to the street in 3 years. Technology diffusion normally takes longer—12 to 15 years for a new technology to go from 10 to 90 percent adoption—but the right policies and innovative business strategies can make adoption much quicker. “Can the U.S. auto industry turn itself around through advanced designs that integrate light materials and new forms of manufacturing?” Lovins asked. Boeing’s experience is evidence that it can. A decade ago, Boeing was “in as deep a crisis as Detroit is now.” No great innovations were in the production pipeline, Airbus was pulling ahead of Boeing, and some people were questioning the company’s future. Boeing’s response was to begin work on the 787 Dreamliner. It used 20 percent less fuel but cost the same. Half of its mass consisted of carbon composites, up from 9 percent in other planes, with bigger windows, a higher-pressure cabin, and other advantages to passengers. “It has had the fastest order takeoff of any jet in history,” Lovins said. “It is sold out well into 2015, and its suite of innovations is being rolled into every plane Boeing makes.” Lovins said that the energy use of six sectors has to change, with at least three probably already past the tipping point. In aviation, Boeing was successful and is now ahead of Airbus. In heavy trucks, Wal-Mart has been leading the way, with much more efficient trucks being introduced into the market where users can buy them. In the military, the Pentagon has emerged as a federal leader in reducing dependence on petroleum. In fuels, there is strong investor interest and industrial activity. And in finance, there has been growing interest in the energy sector, with the clean energy sector getting $117 billion of private risk capital last year. The sixth sector—cars and light trucks—is the toughest sector to change, but progress is being made. The head of Boeing’s commercial airplane division recently moved to Ford to bring ideas from the aerospace industry to the automotive industry. The unions and automobile dealers are keen for innovation, Lovins said, “to save the industry as a tsunami of creative destruction sweeps over them.” The Rocky Mountain Institute has been doing projects with the auto industry. “The level of competition now is producing unthinkable change, and it’s going to change the automakers’ managers, or their minds, whichever comes first.” Governmental policies can hasten these changes. For example, consumers tend to have a very high implicit discount rate, Lovins said, in that they do not consider the fuel savings beyond the first year or two. One way to build the discount rate into the price of a vehicle is through what are called feebates. Consumers pay a fee for buying less efficient vehicles, and the proceeds of that fee are used to offer rebates on more efficient vehicles. “That turns out
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The National Academies Summit on America’s Energy Future: Summary of a Meeting to be extremely powerful and is more profitable for the automakers,” Lovins said, “because to move their offerings from the fee zone into the rebate zone, they add technology content that has a higher [profit] margin than the rest of the vehicle.” The District of Columbia has such a system. “It’s not a feebate, but it walks and quacks like one,” Lovins said. The sales tax for very efficient cars goes to zero, while the sales tax on heavy and inefficient cars, which wear out the streets faster, is higher. It’s an example that “illustrates the opportunities for state-level leadership and experimentation in innovative public policy instruments.” Also, the industry is increasingly interested in feebates as a way of getting more efficient cars on the road faster than with gasoline taxes or standards. As a final example of what is possible, Lovins mentioned the fifth for-profit company that has been spun off from the Rocky Mountain Institute—a company designed to bring a lightweight plug-in hybrid vehicle to market. He said that if half the cars in the country were plug-in hybrids, wind plants could supply them with power, producing as much or more power than all of the nation’s coal plants do now. INITIATIVES UNDER WAY Steven Chu also insisted that new technologies can make a big difference in the transportation sector. For example, in normal use the charge of a battery in a Prius ranges between 40 and 60 percent of its maximum. For a plug-in hybrid or all-electric vehicle, a battery is needed that can discharge 80 or 90 percent of its capacity. For almost a decade, the auto companies and the Department of Energy collaborated on a solid lithium metal battery that had a much higher energy density and could be discharged and recharged more effectively. However, problems with the battery caused the program to be abandoned. Recently, researchers at Lawrence Berkeley National Laboratory have combined a polymer used in the former program with a new compound that overcomes many of the battery’s problems. “After 1,000 deep discharge cycles, 90 percent discharge, [there is] no sign of wear,” Chu said. Extrapolating from that result, such a battery could last for perhaps 10,000 discharge cycles before starting to show signs of wear at 15 years. Dan Reicher also mentioned an effort under way at Google known as RechargeIt. A fleet of hybrid vehicles are being driven by Google employees, with data on their experiences being posted on a publicly available website. The vehicles plug into one of the largest photovoltaic systems in the United States, which covers a large parking structure and many roofs of the company’s buildings. Finally, Ray Orbach mentioned the potential still to be derived from conventional technologies. “Don’t bet against the internal combustion engine,” he
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The National Academies Summit on America’s Energy Future: Summary of a Meeting said. “[Engineers] have worked remarkable things with that engine…. People are coming up with electric drives, but what do we use? Hybrids. I think the internal combustion engine is going to be around for a while.” HYDROGEN AS AN ENERGY SOURCE Hydrogen has many advantages as a fuel for vehicles and as an energy source for buildings, industries, and other energy users, according to Michael Ramage. Its use could reduce petroleum consumption in the United States, making the nation less reliant on foreign sources of oil. It also can be generated from sustainable energy sources, resulting in substantial reductions in greenhouse gas emissions. However, hydrogen also has many hurdles it must overcome before it assumes a major role in any nation’s energy portfolio, Ramage added. Hydrogen must be generated from other energy sources, which can result in greenhouse gas emissions, reliance on uncertain suppliers, or other problems.1 The substantial use of hydrogen would require a massive change in the energy infrastructure of the country. Today, generating hydrogen remains more costly than other sources of energy, and safety issues need to be resolved. Finally, “hurdles to the hydrogen economy are much more than technical,” said Ramage. “They are political and social.” An emphasis on specific problems confronting hydrogen has generated concern and controversy, Ramage noted. Only by viewing hydrogen energy as an integrated system, from production to distribution to use, can its potential as an energy source be assessed. Hydrogen can come from many sources, including fossil fuels, nuclear power, solar power, wind power, or biomass (Figure 9.4). Researchers also are looking at more advanced sources of hydrogen, such as electrolysis of water by genetically engineered microorganisms. Each of these sources has its own advantages and disadvantages. For example, production from fossil fuels releases greenhouse gases, which must either be captured and sequestered or released into the atmosphere. Also, a major source of hydrogen at least initially will be natural gas. But domestic supplies of natural gas are limited, which means that the United States would have to import more natural gas from other countries. Hydrogen production plants can exist at different scales (Figure 9.5). A large central plant could produce on the order of 1 million kilograms of hydrogen per day—enough to fuel about 2 million cars. (A kilogram of hydrogen has about the same energy content as a gallon of gasoline.) Such a plant is about 1 For a full discussion of hydrogen production, see Chapter 6 in NRC and NAE (2004). For more information on the use of hydrogen as an energy source, see NRC (2008a,b).
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The National Academies Summit on America’s Energy Future: Summary of a Meeting FIGURE 9.4 Hydrogen can be produced from many sources. SOURCE: Courtesy of Martin Offutt, IIASA, based on data from L. Burns, General Motors. one-tenth the size of a large U.S. refinery, Ramage said. “For reference, Los Angeles has 10 million cars, and so would need five plants of this size.” A midsize plant could produce enough hydrogen for about 43,000 cars. Such a plant would be a particularly good size for biomass production, Ramage said. Hydrogen production also can be carried out in many small plants, including filling stations for vehicles. The hydrogen could be made at the site through hydrolysis, or it could be generated directly from natural gas. Today the cost of the amount of hydrogen equivalent to a gallon of gasoline made at filling stations from natural gas is about $3.00, assuming a price for natural gas of $6.00 per cubic foot. Such a facility could serve somewhere around 1,000 cars a day. Hydrogen produced from coal would be competitive with gasoline today. But the critical issue is whether the carbon dioxide from the production process would be captured and sequestered. Producing hydrogen from biomass has been getting cheaper, but much more research needs to be done on the use of biomass as an energy source. Considerable research also is needed on the supply system for hydrogen. Hydrogen often will be used as an energy source to power fuel cells that will produce electricity. The performance of fuel cells is therefore a critical issue
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The National Academies Summit on America’s Energy Future: Summary of a Meeting FIGURE 9.5 Hydrogen production plants can be built on different scales. Courtesy of Martin Offutt, IIASA. both during the transition to the widespread use of hydrogen and in the longer term. The cost of power from a fuel cell has fallen from $1,000 per kilowatt in the early 1990s to $300 per kilowatt in the year 2000. For a mass-produced fleet of 500,000 vehicles, the cost would be about $100 per kilowatt today. A feasible but ambitious target would be $30 per kilowatt. The durability of fuel cells also has improved, from 1,000 hours in 2004 to 2,000 hours in 2007. A good target for durability is 5,000 hours, Ramage said. A major challenge for vehicles is to get enough hydrogen onboard the vehicle for it to have a range of about 300 miles, comparable to current vehicles. The best solution appears to be absorbing hydrogen in solid materials, but “this is a major technical challenge,” according to Ramage. At present, automakers are prepared to take vehicles to market that use hydrogen compressed to 10,000 pounds per square inch (psi), and there are already a growing number of demonstration vehicles on the road that have ranges on the order of 300 miles. In the optimally plausible case, which assumes that technical targets are met, that policies are established to support infrastructure change, and that consumers buy the vehicles, hydrogen fuel cell vehicles could make significant inroads into current vehicle markets, Ramage said. If they have a penetration rate comparable to that of hybrid vehicles and then front wheel drive vehicles, there would be a substantial transition toward hydrogen vehicles in the 2025 to
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The National Academies Summit on America’s Energy Future: Summary of a Meeting 2040 time period (Figure 9.6). Such a trend would require a substantial increase in hydrogen production during this period, which would lead to a corresponding reduction in petroleum imports. “Obviously, nobody would assume that hydrogen is going to be our only source of energy,” Ramage said. But such a scenario “shows the kind of impact it could have.” The transition to a new energy regime is discussed in Part IV of this summary, but several points are particular to hydrogen. If hydrogen vehicles become widely available in 2015 and are self-sustaining in 2025, which means that they are cost-effective and people are buying them without government subsidies, the best method of hydrogen distribution during that period will be fueling sites using natural gas. “Natural gas is an energy security issue,” Ramage said, but “you can get a lot of vehicles on the road in the early years with small refining units at the filling station, and most of that technology is in place.” The technology to produce hydrogen from biomass and from coal with sequestration could be developed in the 2020-2025 timeframe, Ramage said. Other large-scale technologies, such as nuclear, solar, and other renewables, then could be developed over a longer timeframe. Under an optimally plausible scenario, U.S. petroleum consumption could be reduced 40 percent by 2035. Energy security would be enhanced, light-duty vehicles would emit half as much carbon dioxide, and 20 percent of the overall U.S. energy used could come from hydrogen. “Equally important,” said Ramage, “it’s a pathway to a sustainable energy future.” FIGURE 9.6 Under an optimistic scenario, fuel cells could account for virtually all vehicle miles traveled in the United States by the middle of the century. ICE, internal combustion engine. SOURCE: Based on Figure 3.1 in NRC and NAE (2004).
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The National Academies Summit on America’s Energy Future: Summary of a Meeting “None of us can really imagine what the energy future is going to look like,” said Ramage. But the transition is sure to require public-private partnering. It also will require public incentives to buy hydrogen-powered vehicles, such as are in place for hybrid vehicles. And the incentives need to be large enough and sustained enough to get through the transition to widespread use of hydrogen. A robust, ongoing program of research and development by both the public and private sectors could make progress on the hurdles hydrogen faces, Ramage said. To name just a few issues: Vehicle and fuel combinations need to be evaluated for their impact on enhancing energy security and reducing carbon dioxide emissions. Details of the transition to hydrogen need to be studied. And strategies to accelerate the innovation process for the needed technologies need to be studied.