. "Appendix H:Other NRC Assessments of Benefits, Costs, and Readiness of Fuel Economy Technologies." Assessment of Fuel Economy Technologies for Light-Duty Vehicles. Washington, DC: The National Academies Press, 2011.
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Assessment of Fuel Economy Technologies for Light-Duty Vehicles
FreedomCAR committee recommended that the Partnership do a thorough cost analysis of the Li-ion batteries under development to account for recent process and materials costs and for increased production rate costs.
A 50 percent reduction in total vehicle weight at no additional cost is another key goal of the Partnership; it would rely on the widespread application of advanced high-strength steels, aluminum alloys, cast magnesium, and carbon-fiber-reinforced plastics. The NRC FreedomCAR committee concluded that the goal of price parity for the lightweight materials is insurmountable within the time frame of the Partnership (NRC, 2008b). However, the 50 percent weight reduction goal is critical for the Partnership’s overall vision of a hydrogen-fueled car. The NRC FreedomCAR committee went beyond that, saying the weight reduction would be mandatory even with the associated cost penalty, because the alternative adjustments to the engine and batteries would cost more. The NRC report recommends maintaining the 50 percent weight reduction goal and analyzing cost-effectiveness to confirm that the added cost of weight reduction can be offset by modifying the fuel cell and battery goals.
THE HYDROGEN REPORT
The tasks of the Committee on Assessment of Resource Needs for Fuel Cell and Hydrogen Technologies (the NRC hydrogen committee) was to establish the maximum practicable number of vehicles that could be fueled by hydrogen by 2020 and to discuss the public and private funding needed to reach that number. The NRC hydrogen committee assumed that (1) the technical goals for fuel cell vehicles, which were less aggressive than those of the FreedomCAR Partnership, are met; (2) that consumers would readily accept such vehicles; (3) that government policies would drive the introduction of fuel cell vehicles and hydrogen production and infrastructure at least to the point where fuel cell vehicles are competitive on the basis of lifecycle cost; and (4) that oil prices are at least $100 per barrel by 2020 (NRC, 2008a). Thus, the scenarios developed in the hydrogen report are not projections but a maximum possible future market if all assumptions are met. The NRC hydrogen committee concluded that although durable fuel cell systems at significantly lower costs are likely to be increasingly available for light-duty vehicles over the next 5 to 10 years, the FreedomCAR Partnership goals for 2015 are not likely to be met. The NRC hydrogen committee also concluded that commercialization and growth of these hydrogen fuel cell vehicles could get under way by 2015 if supported by strong government policies. Those conclusions are more optimistic than the conclusions on fuel cells contained in this report, whose committee (though it did not consider the potential impact of policies on fuel cell market potential) does not expect progress on fuel cell costs and technology to be as rapid as expected by the NRC hydrogen committee. Further, one OEM that is aggressively pursuing fuel cell vehicles will probably not be in a position to begin significant commercialization until at least 2020, 5 years later than the target date assumed in the hydrogen study.
The task also called for the NRC hydrogen committee to consider whether other technologies could achieve significant CO2 and oil reductions by 2020. The NRC hydrogen committee considered improvements to spark-ignition (SI) engines, compression-ignition (CI) engines, vehicle transmissions, and hybrid vehicle technologies as well as reductions in weight and other vehicle load reductions. Improvements also could come in the form of reductions in weight and similar improvements. The technical improvements that can be applied to SI engines include variable valve timing and lift, camless valve actuation, cylinder deactivation, the use of gasoline direct injection with turbocharging, and intelligent start-stop, which involves engine shutoff when the vehicle idles. Improvements in vehicle transmissions include the use of conventional 6/7/8-speed automatic transmissions and automated manual transmissions. This report repeats an estimate from Duleep (2007) that combining the projections for improvements in the engine, transmission, weight, parasitic loss (including friction losses, rolling resistance, and air drag), accessories, and idle-stop components could reduce fuel consumption in 2015 by 21 to 29 percent relative to today’s vehicles and in 2025 by 31 to 37 percent. Table H.1 shows the improvements estimated for SI engines attributable to these approaches. The NRC hydrogen report also quotes studies by Heywood and colleagues at Massachusetts Institute of Technology (MIT) on the fuel efficiency of lightduty vehicles (Weiss et al., 2000; Heywood, 2007; Kasseris and Heywood, 2007; Kromer and Heywood, 2007). The fuel economy improvements noted in the MIT work result from changes to the engines and transmissions and appropriate reductions in vehicle weight. The MIT work assumes that the improvements are aimed entirely at reducing fuel consumption. Table H.2 shows the improvements in fuel economy compared to a 2005 SI engine vehicle that MIT estimates could be achieved by 2030, although the NRC hydrogen committee assumed that these levels of fuel economy would not be available as quickly.
TABLE H.1 Potential Reductions in Fuel Consumption (gallons per mile) for Spark-Ignition Vehicles Expected from Advances in Conventional Vehicle Technology by Category, Projected to 2025
Engine and transmission
Weight, drag, and tire loss reduction
NOTE: Values for 2016-2025 include those of 2006-2015.