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Using 2014 U.S. light duty PEV registrations by make and model, this paper assesses the causes of Plug-in Electric Vehicle (PEV) success across U.S. states focusing on areas that had incentive and utility programs supporting PEV adoption. Market segments investigated were (1) luxury/performance (&gt, $60,000 list price), (2) mid-market ($40-50,000), (3) mass market (&lt, $40.000), and (4) total. States with either exclusive or preferential BEV incentives are a focus. BEV-biased incentives proved to be very effective in promoting mass market BEVs. After controlling for these attributes, case studies for several utility service areas were conducted to gauge whether PEVs were more or less successfully implemented via outreach by those utilities. These investigations suggest ways that utilities can successfully increase PEV registrations, after taking local climate and state incentives into consideration.

An international comparative analysis of causes of variation of PEV sales rates per capita in selected U.S. states, Canadian provinces, and European Nations is conducted. 2014-15 light-duty PEV registrations/sales by make and model are examined, drawing heavily on 2014 data for aggregate comparisons. States, provinces, and nations with PEV success, but with widely varying PEV purchase incentives and charging infrastructure installations are examined. The paper focuses particularly presence or absence of long daily distance charging options for PEVs. Four questions are addressed. (1) European evidence is that PHEV powertrains are a very marketable option for large family vehicles. For small BEVs BMW i3 sales patterns indicate that range extension beyond 120 km but less than 240 km via gasoline significantly increases market share. BEV inter-city functionality provided by aggressive installation of DC fast charging was critical to overall PEV success in Norway. Norway, like Northern Europe and Canada has a utility network that is winter peaking, which allows provision of peak summer BEV long-distance charging needs without difficulty. This is not the case for the U.S., which is summer peaking. The reviewed states, provinces, and nations vary considerably in seasonal peak temperature extremes. These climate differences have a significant bearing on the local viability of PHEVs vs. BEVs. The long distance DC fast charging infrastructure investments needed to support BEV market success are not as large when PHEVs are preferred by consumers.

Vehicles with electrified powertrains such as hybrid electric vehicles, plug-in hybrid electric vehicles (PHEVs), and all-electric vehicles (AEVs, which use grid-supplied battery energy exclusively) are potentially marketable because of their low operating costs. However, each vehicle type incurs a significant initial cost penalty compared with a conventional vehicle powered by an internal combustion engine. Three PHEV cars and an AEV car are selected to assess cost-effectiveness from the consumers' perspective. Daily travel to and from work is isolated from other vehicle travel data from the U.S. National Household Travel Survey, and five daily distance categories are investigated. Three driving cycle runs are used: one developed by following cars in Los Angeles, California, in 1992, the Worldwide Harmonized Light-Duty Test Cycle, and a real driving record selected from the Kansas City metropolitan area in Kansas and Missouri. Probable charging patterns for each PHEV and the AEV are investigated for three of five daily distance categories. Overnight charging and workplace charging also are examined. The possibility for multiple charges at work is considered, as is the possibility of a charge after work, before the day's end. The degree of importance of spending a given pool of money to upgrade a residential (versus workplace) charging station is discussed. Two indicators of effectiveness of battery pack utilization are developed [a charge-depleting effectiveness factor and grid kilowatt-hours used per day per dollar of incremental vehicle expense (cost-effectiveness)], and target markets for cars used for work for each powertrain type are suggested.

Plug-in electric vehicle (PHEV) technology is seen as promising technology for reducing oil use, improving local air quality, and/or possibly reducing GHG emissions to support a sustainable transportation system. This paper examines the usage of household vehicles to support assessment of the market potential of plug-in hybrid electric vehicles (PHEVs), the higher purchase price of which requires high usage rates to pay off the investment in the technology. According to the 2009 National Household Travel Survey (NHTS), about 40% of household vehicles were not used on the survey travel day [1]. This study analyzed household vehicle use and non-use by vehicle type, age, area type (metropolitan statistical area [MSA] and non-MSA), and population density. Vehicles used on survey day with or without a reported travel time and distance in the survey are considered “vehicles used”. All others are referred to as “vehicles not used”. We divided the “vehicles not used” into three categories: 1) left at home while other household vehicles were used; 2) not used because travelers used other modes; and 3) no household trips. The “vehicle used” consists of two categories: 1) those with distance and time data and 2) those with no travel data. Within these five categories, vehicles were subdivided according to four vehicle types: car, van, SUV, and pickup. Each vehicle type was further subdivided in two age groups: 10 years or less (≤10) and more than 10 years (>10). In addition, vehicle usage was compared in both MSAs and non-MSAs and during weekdays and weekends. Results indicate that most vehicles—especially pickups—are not used because the households own and use other vehicles. Moreover, SUVs—especially newer SUVs (≤10 years)—are the most utilized vehicle type and should be strongly considered as a primary vehicle type for PHEVs, in addition to cars.

This paper analyses the cost competitiveness of different electrified propulsion technologies for the German auto market in 2020. Several types of hybrid electric vehicles including parallel hybrids (with and without external charging) and a serial range extended electric vehicle are compared to a conventional car with SI engine, a full battery electric vehicle and a hydrogen powered fuel cell vehicle. Special focus lies on the maintenance and repair cost and the expected resale value of alternative vehicles, which have been integrated within one extensive total cost of ownership model. The assessment shows that the current TCO gaps for alternative drivetrains will decrease significantly by 2020 mainly driven by the reduction in production cost. Furthermore hybrid electric vehicles will profit from lower maintenance and repair cost and a higher expected resale value compared to conventional cars. Therefore, hybrid electric vehicles will be an attractive option in particular for users with high annual mileages, who can benefit from the low operating cost of EVs in combination with unlimited driving range. The analysis concludes that there will not be one dominant powertrain design in the midterm future. Hence, automakers have to manage a wide portfolio of competing drivetrain architectures, which will increase the risk and complexity of strategic decisions.

Using the 2009 National Household Transportation Survey (NHTS), an analysis of opportunity charging potential during daytime, for the time interval when a car or SUV is parked for the longest duration, is presented here. We focus on charging at 3.3 kW or less, either using the charger at the dwelling unit a second time per day (a one charger solution), or using a second charge point at work. Our earlier research with the 2009 NHTS indicates that nearly 60% of vehicles within this sample were driven to work, or returned to home between 6:00 AM and 6:00 PM. In this analysis we consider the potential for daytime charging before summertime afternoon utility load peaks, anticipating that Public Utility Commissions (PUCs) supporting smart grid pricing strategies may impose much higher electricity costs at these times. We consider kW ratings of typical opportunity chargers versus overnight chargers. We consider the plug-in hybrid with 28 km of urban electric range (PHEV28), the extended range electric vehicle with 56 km of universal all-electric operation capability (EREV56) and the battery electric vehicle with 117 km of electric range (BEV117). Electricity demand and gasoline fueled miles reduction is examined for the average circumstance in two daily distance brackets (48-80 km, 80-160 km) and for two charging behaviors – (1) overnight and (2) both overnight and during the longest duration parking event of daytime hours, from 6 am to 6 pm.

This study systematically examined the potential impacts of recharging scenarios for multiple plug-in hybrid electric vehicles (PHEVs) in the western United States—in particular, the service area of the Western Electricity Coordinating Council (WECC)—in 2030. The goal of the study was twofold: to examine the impact of scenarios for market penetration and charging of PHEVs on the electric utilities and transmission grid and to estimate the potential reductions in petroleum use and greenhouse gas (GHG) emissions attributable to PHEV miles traveled on primarily grid electricity. Three charging scenarios for PHEVS were examined: (a) begin recharging upon arrival at home at the end of the last daily trip, (b) complete recharging of batteries just before the start of the first daily trip, and (c) any additional charging opportunity during the daytime. The three charging scenarios produced distinct hourly electric load profiles, with the opportunity-charging scenario resulting in a significant increase in load during the daytime. However, when the utility dispatch simulations were run for these charging scenarios in the WECC area, they all exhibited similar marginal-generation mixes (dominated by the natural gas combined-cycle technology) to satisfy the PHEV load, and GHG emissions were within 2% of each other. A well-to-wheel analysis revealed that the marginal-generation mixes produced 40% to 45% lower GHG emissions by PHEVs than did conventional gasoline internal combustion engine vehicles.

This paper delineates the various issues involved in developing reliable estimates of the petroleum use reduction that would result from the widespread introduction of plug-in hybrid electric vehicles (PHEVs). Travel day data from the 2001 National Household Travel Survey (NHTS) were analyzed to identify the share of vehicle miles of travel (VMT) that could be transferred to grid electricity. Various PHEV charge-depleting (CD) ranges were evaluated, and 100% CD mode and potential blended modes were analyzed. The NHTS data were also examined to evaluate the potential for PHEV battery charging multiple times a day. Data from the 2005 American Housing Survey (AHS) were analyzed to evaluate the availability of garages and carports for at-home charging of the PHEV battery. The AHS data were also reviewed by census region and household location within or outside metropolitan statistical areas. To illustrate the lag times involved, the historical new vehicle market share increases for the diesel power train in France (a highly successful case) and the emerging hybrid electric vehicles in the United States were examined. A new vehicle technology substitution model is applied to illustrate a historically plausible successful new PHEV market share expansion. The trends in U.S. light-duty vehicle sales and light-duty vehicle stock were evaluated to estimate the time required for hypothetical successful new PHEVs to achieve the ultimately attainable share of the existing vehicle stock. Only when such steps have been accomplished will the full oil savings potential for the nation be achieved.

In this paper, we assess the performance of the BEA series “value of motor vehicle output” as an indicator of the business cycle over the period 1968–2007. We statistically assess the causal relationship between real motor vehicle output (RMVO) and real gross domestic product (RGDP). This is accomplished by standard estimation and statistical methods used to assess vector autoregressive models. This assessment represents the initial results of a more encompassing research project, the intent of which is to determine the dynamic interaction of the transport sector with the overall economy. It’s a start to a more comprehensive assessment of how transport and economic activity interrelate.

Estimation of the potential of plug-in hybrid electric vehicles’ (PHEV’s) ability to reduce U.S. gasoline use is difficult and complex. Although techniques have been proposed to estimate the vehicle kilometers of travel (VKT) that can be electrified, these methods may be inadequate and/or inappropriate for early market introduction circumstances. Factors that must be considered with respect to the PHEV itself include (1) kWh battery storage capability, (2) kWh/km depletion rate of the vehicle (3) liters/km use of gasoline (4) average daily kilometers driven (5) annual share of trips exceeding the battery depletion distance (6) driving cycle(s) (7) charger location [i.e. on-board or off-board] (8) charging rate. Each of these factors is actually a variable, and many interact. Off the vehicle, considerations include (a) primary overnight charging spot [garage, carport, parking garage or lot, on street], (b) availability of primary and secondary charging locations [i.e. dwellings, workplaces, stores, etc] (c) time of day electric rates (d) seasonal electric rates (e) types of streets and highways typically traversed during most probable trips depleting battery charge [i.e. city, suburban, rural and high vs. low density], (f) cumulative trips per day from charger origin (g) top speeds and peak acceleration rates required to make usual trips. Taking into account PHEV design trade-off possibilities (kW vs. kWh of battery, in particular), this paper attempts to extract useful information relating to these topics from the 2001 National Household Travel Survey (NHTS), and the 2005 American Housing Survey (AHS). Costs per kWh of PHEVs capable of charge depleting (CD) all-electric range (CDE, or AER) vs. those CD in “blended” mode (CDB) are examined. .Lifetime fuel savings of alternative PHEV operating/utilization strategies are compared to battery cost estimates.

The positions of the diesel and hybrid light-duty passenger vehicles in the technology adoption life cycle are examined with a mid-2004 stated preference study of 1,036 households. Implications of the technology life cycle for historical consumer preference estimates obtained for use in prior models of market share are briefly discussed. The hypothetical life-cycle segments addressed in this paper are early adopters, early buyers, and majority buyers. Survey respondents are segmented into subgroups, or markets, in light of hypothesized attributes of consumers within the product life cycle. Emphasis is placed on delineating the preferences of new instead of used vehicle buyer segments. These categories are compared with the five categories in the high-tech technology adoption life-cycle paradigm of G. Moore. One purpose of the analysis is to use the survey as a test of the reasonableness of the three categories used here. The implications of the survey for use of the rational buyer model of consumer trade-offs of incremental new vehicle capital cost (of a diesel or hybrid) against reduced fuel cost are addressed. Competition of desires for fuel efficiency, acceleration, and towing is also addressed, as are the effects of gender, income, education, and age.

Although many studies that use vehicle simulation models to estimate fuel economy gains for a range of hybrid vehicles have attempted to control for the comparability of performance between conventional and hybrid vehicles, different rules and simulation models have been used. The fuel economy gain estimates versus performance change for a set of those studies are reviewed, and causes for the wide range in estimates of fuel economy gain when hybridizing a gasoline-fueled vehicle are examined. Data are compiled, and relationships are discussed in detail for 18 cases: three studies of four or more cases each. The data are used to develop statistical models to evaluate the causes of variation in fuel economy gain within and across the studies. Three studies (each evaluating one case only) that predict lower fuel economy gains than the first three are also examined. Explanations and adjustments are provided to illustrate that the differences across the studies are less than a cursory reading would imply. Most notably, potential fuel economy gain via hybridization increases as the 0-to-60-mph times of the compared vehicle pairs drop (and power-toweight ratios increase). Also a reduction in engine power is necessary to obtain large benefits. The most complex statistical model developed indicates that an increase in electric motor power relative to engine power improves the fuel economy of hybrids, up to a point. Finally, results indicate that continuous top-speed and grade-climbing ability will drop if a less powerful engine is used.

The Partnership for a New Generation of Vehicles (PNGV), a government and industry joint initiative, has established a goal of tripling the fuel economy of a midsize sedan. A series of modeling experiments was conducted to examine the relative effectiveness of various technical steps cumulatively accomplishing this goal. A composite 1995 midsize sedan was sequentially modified, resulting in 21 different vehicles, each with selectively singularly altered candidate technical modifications that are evaluated with respect to their effectiveness for increasing fuel economy. The candidate technical modifications included manual transmission; reduced acceleration requirement; reduced frontal area and coefficient of drag; low-resistance tires; lightweight material; fuel-efficient, turbocharged, direct-injection diesel engine; hybridizing to a parallel configuration; and lower grade-climbing requirements. The study design is discussed, and simulated fuel economy gain for each step is presented. The modeling exercise also estimated that it is possible to reach the triplefuel-economy goal with these modifications.

Toyota’s introduction of a hybrid electric vehicle (HEV) named “Prius” in Japan and Honda’s proposed introduction of an HEV in the United States have generated considerable interest in the long-term viability of such fuel-efficient vehicles. A performance and cost projection model developed entirely at Argonne National Laboratory (ANL) is used to estimate costs. ANL staff developed fuel economy estimates by extending conventional vehicle modeling done primarily under the National Cooperative Highway Research Program. Together, these estimates are employed to analyze dollar costs versus benefits of two of many possible HEV technologies. Incremental costs and fuel savings are projected for a Prius-type low-performance hybrid (14.3-s 0 to 60 mph acceleration, Z60 time) and a higher-performance “mild” hybrid vehicle (11-s Z60 time). Each HEV is compared with a U.S. Toyota Corolla with automatic transmission (11-s Z60 time). The base incremental retail price range, projected a decade hence, is $3,200–$3,750, before considering battery replacement cost. Historical data are analyzed to evaluate the effect of fuel price on consumer preferences for vehicle fuel economy, performance, and size. The relationship among fuel price, the level of change in fuel price, and consumer attitude toward higher fuel efficiency also is evaluated. A recent survey on the value of higher fuel efficiency is presented and U.S. commercial viability of the hybrids is evaluated using discount rates of 20 percent and 8 percent. The analysis, with its current HEV cost estimates and current fuel savings estimates, implies that the U.S. market for such HEVs would be quite limited.

This paper examines three issues related to both the U.S. and world oil supply: (1) the nature of the long-term, postpeak production profile for the U.S. and, by inference, other regions (the Hubbert curve is used as a “strawman” model); (2) implications on U.S. energy security of using a modified Hubbert-type conceptual model of prepeak production, testing the adequacy of Latin America to be the primary source of U.S. oil imports; and (3) the cyclic behavior of oil prices. it shows that U.S. production will exhibit a more attenuated decline than that simulated by the Hubbert curve and not decline to zero. it asserts that U.S. production is better predicted by past reserves than past production, but that this argument does not apply to nations that keep a much larger proportion of reserves in the ground. Such nations could considerably expand production without any growth in reserves. The paper concedes that the potential total production for these nations could be examined with a Hubbert curve model linked to reserves, but with great uncertainty. Such an uncertain optimistic forecast predicts that the cumulative production of Latin America could far exceed that of the United States. Nevertheless, a statistical model of oil prices since 1870 implies that real wellhead oil prices in the United States are on a long-term upward path, underlying a much more “noisy” cyclical pattern estimated to include 22- and 27-year cycles. The statistical model predicts a severe oil shock within a few years (of 1998) but also predicts that through 2030, real oil prices will not reach 1981 levels again. The paper examines U.S. and world trends in seismic exploration, drilling locations and depths, drilling costs, oil/gas reserves, oil/gas use rates, and oil demand. After taking these factors into consideration, it concludes that the statistical model of oil prices cannot be disputed, despite its lack of basis in economic theory.

The ongoing investigation into the determinants of alternative fuel vehicle choice is described. A stated preference vehicle choice survey was conducted for the 47 continental U.S. states, excluding California. The national survey is based on, and is an extension of, previous studies on alternative fuel vehicle choice for the state of California conducted by the University of California’s Institute of Transportation Studies. Several vehicle choice models are being developed on the basis of the survey information. Preliminary model estimates using the national survey alone plus estimates for a "pooled" model using both California and national survey information are presented.

Plug-in electric vehicles (PEV) are considered to be a potentially sustainable alternative to conventional vehicles for private transport and a way of balancing intermittent generation from renewable energy sources (RES). Using RES for electric mobility would be superior to all available fossil generation alternatives in terms of emissions and efficient energy conversion. To quantify the marginal energy from RES used, two charging strategies last trip charging and optimized demand-side management (DSM) with dynamic pricing are investigated for a German long-term high RES power mix scenario. The results for both charging cases indicate that the power demand for PEVs will not be met by RES. For last trip charging 1.40% comes from RES. In terms of DSM this share increases to 7.38% but results in higher overall CO2 emissions because for Germany coal provides the lowest cost fossil power. Hence DSM charging reduces peak load and helps to balance RES generation but is contrary to the original idea of clean transportation because of higher marginal emissions caused by the utilisation of coal. To account for contractual arrangements allowing consumers to directly purchase RES electricity, a second scenario with additional installed RES capacity is analysed. Because of the high RES share of over 50 % a complete usage of the RES is not possible and a small fraction of power must still be provided by dispatchable power plants. For the second scenario, DSM charging also allows for an increased use of RES compared to last trip charging (99 % versus 90% RES). In addition, total marginal CO2 emissions are lower and DSM helps to balance the ramping of RES. Therefore, it is concluded that for Germany the installation of additional RES and DSM charging would guarantee clean transportation using electric vehicles.

In this study, we developed a model for calculating the costs of lithium-ion batteries supporting electric drive in light duty passenger vehicles (LDVs). The model calculates the annual materials requirements from design criteria for the battery pack including power, capacity, number of cells, and cell chemistry parameters. The costs of capital equipment, plant area and labor for each step in the manufacturing process were estimated for a baseline plant. These costs are adjusted for each battery pack studied by comparing the processing rate pertinent for each step (area to be coated, number of cells to be tested, etc.) with that of the baseline process and applying correction factors. We applied the cost modelling method to batteries with four lithium-ion cell chemistries and for several levels of capacity and power. For quality assurance purposes, electrode coating thicknesses are limited to 100 microns by the model. The result of this restriction is that as the capacity of the cells is increased to achieve longer range under electric power, the electrode area and the cell power are also increased and the power of the entire battery pack is also increased. In simulations of our reference chemistry for 16, 32 and 48 -km PHEVs there is almost no cost increase for increasing the pack power from 40 to 60kW, for PHEVs with 48- and 64 km electric range, there was almost no additional cost for power up to 90 kW. For a set value of pack energy storage, a small number of high capacity cells are much less expensive to manufacture than a large number of low-capacity cells. The useable fraction of the state-of-charge range for a battery system is shown to be an important cost factor. In view of cost similarities, the choice of cell chemistry will probably depend more on proven safety, reliability, and long life rather than on initial cost.

This report focuses on various major long-range (1977-2002) and intermediate-range (1982-2002) U.S. commercial trucking trends. The primary sources of data for this period were the U.S. Bureau of the Census Vehicle Inventory and Use Survey and Truck Inventory and Use Survey. In addition, selected 1977-2002 data from the U.S. Department of Energy/Energy Information Administration and from the U.S. Department of Transportation/Federal Highway Administration's Highway Statistics were used. The report analyzes (1) overall gasoline and diesel fuel consumption patterns by passenger vehicles and trucks and (2) the population changes and fuels used by all commercial truck classes by selected truck type (single unit or combination), during specified time periods, with cargo-hauling commercial trucks given special emphasis. It also assesses trends in selected vehicle miles traveled, gallons per vehicle miles traveled, and gallons per cargo ton-mile traveled, as well as the effect of cargo tons per truck on fuel consumption. In addition, the report examines long-range trends for related factors (e.g., long-haul mileages driven by heavy trucks) and their impacts on reducing fuel consumption per cargo-ton-mile and the relative shares of total commercial fuel use among truck classes. It identifies the effects of these trends on U.S. petroleum consumption. The report also discusses basic engineering design and performance, national legislation on interstate highway construction, national demographic trends (e.g., suburbanization), and changes in U.S. corporate operations requirements, and it highlights their impacts on both the long-distance hauling and shorter-distance urban and suburban delivery markets of the commercial trucking industry.

The relative fuel consumption reduction strengths of multiple passenger car powertrains are investigated. These include [A] conventional compression ignition (CI) direct injection (DI) turbocharged (TC) diesel (D) [CI-DI-TC-D], [B] Atkinson cycle charge sustaining (CS) “split-hybrid” electric vehicles (HEV) fueled by gasoline/petrol (G) [HEVG], plug-in (P) hybrid gasoline/petrol [PHEVG)], and indirect fuel injected (IDI) spark-ignited (SI) internal combustion engines (ICE) fueled by gasoline/petrol [SI-IDI-NA-G]. When we use simulation to evaluate the behavior of PHEVG powertrains, the size is a four-to-five passenger car platform that would be regarded as “compact” in the U.S. and standard in Europe. A careful distinction between probable driving patterns for PHEVGs when in charge-depletion (CD) mode vs. charge sustaining (CS) operation is made. Effects of variation in the amount of kWh storage and the CD strategy, between PHEVs with varying km of electric-equivalent range are also investigated. The effect of electric drive (battery and motor) power (kW) on ability of a vehicle to operate all-electrically, relative to its ability to reduce oil use, is examined. Four degrees of hybridization are briefly examined, including stop-start (SS), integrated starter-generator (ISG), mild parallel (MP), and full parallel (FP). Each of the parallel PHEVs examined is an FP. Powertrain model simulations and limited dynamometer test results for such PHEVGs are compared to the other vehicle types for certification and “on-road” driving cycles from Europe and the U.S. It is illustrated that the conventional wisdom that HEVG has significant superiority over CG primarily in urban stop and go driving should not automatically be extended to PHEVGs. The driving cycle information is related to systematically varying consumer patterns of dwelling choice and vehicle use in cities, suburbs, and rural areas, as well as across nations. Effects of fuel taxation choices by nation — for gasoline, diesel and electric fuel — are investigated. The effects that residential location and type, driving cycle, and fuel cost have on the relative marketability of the studied powertrains, when initially entering the market, are summarized. The sequence of events leading to early emergence of original equipment automaker production and marketing of PHEVGs is discussed.

The strong correlation between vehicle weight and fuel economy for conventional vehicles (CVs) is considered common knowledge, and the relationship of mass reduction to fuel consumption reduction for conventional vehicles (CVs) is often cited without separating effects of powertrain vs. vehicle body (glider), nor on the ground of equivalent vehicle performance level. This paper challenges the assumption that this relationship is easily summarized. Further, for hybrid electric vehicles (HEVs) the relationship between mass, performance and fuel consumption is not the same as for CVs, and vary with hybrid types. For fully functioning (all wheel regeneration) hybrid vehicles, where battery pack and motor(s) have enough power and energy storage, a very large fraction of kinetic energy is recovered and engine idling is effectively eliminated. This paper assesses two important impacts of shifting from conventional to hybrid vehicles in terms of the mass vs. fuel economy relationship - (1) significant improvements in fuel economy with little or no change in mass, and (2) once a switch to hybrid powertrains has been made, the effectiveness of mass reduction in improving fuel economy will be diminished relative to conventional vehicles. In this paper, we discuss vehicle tractive load breakdowns and impacts of hybridization onmore » vehicle efficiency, discuss capture of kinetic energy by conversion to electrical energy via regenerative braking, assess benefits of shutting off the engine when the vehicle does not require power, and investigate energy losses associated with vehicle mass.« less

This paper analyzes fuel economy benefits of direct hydrogen and gasoline reformer fuel cell vehicles, with special focus on cold-start impacts on these fuel cell based vehicles. Comparing several existing influential studies reveals that the most probable estimates from these studies differ greatly on the implied benefits of both types of fuel cell vehicles at the tank-to-wheel level (vehicle-powertrain efficiency and/or specific power), leading to great uncertainties in estimating well-to-wheel fuel energy and/or greenhouse gas (GHG) emission reduction potentials. This paper first addresses methodological issues to influence the outcome of these analyses. With one exception, we find that these studies consistently ignore cold-start and warm-up issues, which play important roles in determining both energy penalties and start-up time of fuel cell vehicles. To better understand cold-start and warm-up behavior, this paper examines approaches and results based on two available U.S. Department of Energy and USCAR funded National Laboratory vehicle simulation models -PSAT and ADVISOR. Our analysis reveals that the predicted cold-start effects are influenced by assumed choices concerning trade-offs between maximizing warm-up rate vs. minimizing wasteful energy during cold-starts, time to achievement of full power capability, and different modeling approaches. It appears that different cold-start warm-up strategies could result in a wide range of (1) vehicle performance capabilities as a function of time from start-up and (2) associated cold-start net energy penalties.

This paper analyzes four recent major studies carried out by MIT, a GM-led team, Directed Technologies, Inc., and A. D. Little, Inc. to assess advanced technology vehicles. These analyses appear to differ greatly concerning their perception of the energy benefits of advanced technology vehicles, leading to great uncertainties in estimating full-fuel-cycle (or "well-to-wheel") greenhouse gas (GHG) emission reduction potentials and/or fuel feedstock requirements per mile of service. Advanced vehicles include, but are not limited to, advanced gasoline and diesel internal combustion engine (ICE) vehicles, hybrid electric vehicles (HEVs) with gasoline, diesel, and compressed natural gas (CNG) ICEs, and various kinds of fuel-cell based vehicles (FCVs), such as direct hydrogen FCVs and gasoline or methanol fuel-based FCVs. We focus on variations in estimates of vehicle gasoline-equivalent fuel energy use, glider and powertrain masses, and introduce powertrain effectiveness as a new surrogate measure for tank-to-wheel vehicle efficiency. We conclude that, while the degree of uncertainty across studies is considerable, it is not as great as a summary investigation and direct comparison implies. Our investigation suggests that there are logical and systematic reasons for variations among the studies. Further studies are required to improve both assessment and understanding of technical potentials of these advanced technologies, and to narrow the range of uncertainty currently present.

Several studies, conducted from 1997 to 2001, have employed vehicle and powertrain simulation models to estimate fuel economy gains for a variety of fuel-cell powertrains. Many of those studies have attempted to control for the comparability of performance between conventional and fuel-cell vehicles (FCVs), but different sets of performance goals and simulation models have been used. This paper reviews the estimates of fuel economy gain (in mpg) vs. varying measures of performance change for a set of those studies. We examine some of the potential causes for the variability of these estimates — fuel used, powertrain hybridization, vehicle raw energy requirements (load), and variations in analysts’ assumptions/estimates — when substituting several types of fuel-cell powertrains. Our study includes development of a database and detailed examination of the relationships among powertrain and vehicle characteristics and fuel economy gain estimates for the selected studies. We developed simple equations by powertrain type to systematically examine the causes of variation in mpg gain among those conventional/FCV pairs controlled to have the same peak kW per kg of vehicle test weight (a surrogate for acceleration capability).

Although many of the studies that use vehicle simulation models to estimate fuel economy gains for a range of hybrid vehicles have attempted to control for the comparability of performance between conventional and hybrid vehicles, different rules and simulation models have been used. This paper reviews the estimates of city, highway, and corporate average fuel economy gain vs. varying measures of performance change for a set of those studies. We examine the causes for the wide range in estimates when hybridizing a vehicle, establish a database, and provide detailed discussions of relationships using several of the studies. Statistical models developed on the basis of the data reveal the causes of variation in mpg gain among conventional/hybrid pairs that have the same 0–60 mph acceleration times. Our study reveals that potential mpg gain via hybridization is greater as the 0–60 mph acceleration time of the pair of compared vehicles drops (and power-to-weight ratios increase). We demonstrate that engine downsizing is necessary to obtain large benefits, and that an increase in electric motor power relative to engine power — up to a point — improves the fuel economy of hybrids.

Hybrid electric vehicles (HEVs) offer great promise in improving fuel economy. In this paper, we analyze why, how, and by how much vehicle hybridization can reduce energy consumption and improve fuel economy. Our analysis focuses on efficiency gains associated solely with vehicle hybridization. We do not consider such other measures as vehicle weight reduction or air- and tire-resistance reduction, because such measures would also benefit conventional technology vehicles. The analysis starts with understanding the energy inefficiencies of light-duty vehicles associated with different operation modes in US and Japanese urban and highway driving cycles, with the corresponding energy-saving potentials. The potential for fuel economy gains due to vehicle hybridization can be estimated almost exclusively on the basis of three elements: the reducibility of engine idling operation, the recoverability of braking energy losses, and the capability of improving engine load profiles to gain efficiency associated with specific HEV configurations and control strategies. Specifically, we evaluate the energy efficiencies and fuel economies of a baseline MY97 Corolla-like conventional vehicle (CV), a hypothetical Corolla-based minimal hybrid vehicle (MHV), and a MY98 Prius-like full hybrid vehicle (FHV). We then estimate energy benefits of both MHVs and FHVs over CVs on a performance-equivalent basis. We conclude that the energy benefits of hybridization vary not only with test cycles, but also with performance requirements. The hybrid benefits are greater for ''Corolla (high) performance-equivalent'' vehicles than for ''Prius (low) performance-equivalent'' vehicles. An increasing acceleration requirement would result in larger fuel economy benefits from vehicle hybridization.

To address the uncertainty regarding future costs and operating attributes of electric and hybrid electric vehicles, a two stage, worldwide Delphi study was conducted. Expert opinions on vehicle attributes, current state of the technology, possible advancements, costs, and market penetration potential were sought for the years 2000, 2010, and 2020. Opinions related to such critical components as batteries, electric drive systems, and hybrid vehicle engines, as well as their respective technical and economic viabilities, were also obtained. This report contains descriptions of the survey methodology, analytical approach, and results of the analysis of survey data, together with a summary of other factors that will influence the degree of market success of electric and hybrid electric vehicle technologies. Responses by industry participants, the largest fraction among all the participating groups, are compared with the overall responses. An evaluation of changes between the two Delphi stages is also summarized. An analysis of battery replacement costs for various types is summarized, and variable operating costs for electric and hybrid vehicles are compared with those of conventional vehicles. A market penetration analysis is summarized, in which projected market shares from the survey are compared with predictions of shares on the basis of two market share projection models that use the cost and physical attributes provided by the survey. Finally, projections of market shares beyond the year 2020 are developed by use of constrained logit models of market shares, statistically fitted to the survey data.

Uncertainty about future costs and operating attributes of electric drive vehicles (EVs and HEVs) has contributed to considerable debate regarding the market viability of such vehicles. One way to deal with such uncertainty, common to most emerging technologies, is to pool the judgments of experts in the field. Data from a two-stage Delphi study are used to project the future costs and operating characteristics of electric drive vehicles. The experts projected basic vehicle characteristics for EVs and HEVs for the period 2000-2020. They projected the mean EV range at 179 km in 2000, 270 km in 2010, and 358 km in 2020. The mean HEV range on battery power was projected as 145 km in 2000, 212 km in 2010, and 244 km in 2020. Experts` opinions on 10 battery technologies are analyzed and characteristics of initial battery packs for the mean power requirements are presented. A procedure to compute the cost of replacement battery packs is described, and the resulting replacement costs are presented. Projected vehicle purchase prices and fuel and maintenance costs are also presented. The vehicle purchase price and curb weight predictions would be difficult to achieve with the mean battery characteristics. With the battery replacement costs added to the fuel and maintenance costs, the conventional ICE vehicle is projected to have a clear advantage over electric drive vehicles through the projection period.

This study was conducted to collect information for a technical and economic assessment of electric (EV) and hybrid (HEV) vehicles. The first-stage worldwide survey was completed in fall 1994, while the second-stage was completed by summer 1995. The paper reports results from the second round of the survey and major differences between the two rounds. This second-stage international survey obtained information from 93 expert respondents from the automotive technology field. Key results: EVs will penetrate the market first, followed by internal combustion engine HEVs, while gas turbine and fuel cell HEVs will come after 2020. By 2020, EVs and internal combustion engine HEVs will have a 15% share of the new vehicle market; they will also cost 18-50% more and will be slightly inferior to 1993 gasoline cars. AC induction motor is projected to be superior to DC and DC brushless motors by 2020, although the DC motor will be less expensive in 2000. DC brushless motors are projected to be the most expensive. Though generally declining, battery costs will remain high. EVs are believed to be effective in reducing urban emissions; however, their costs must be reduced drastically. Petroleum is expected to be the predominant fuel for hybrid vehicles through 2020. Mean energy equivalent fuel economy of electric drivetrain vehicles is projected to be 20-40% greater than for conventional vehicles in 2000, and to rise a few percents during the projection period. Respondents anticipate only a 16% increase in conventional vehicle fuel economy from 2000 to 2020.

Statistical analyses of the acceleration capability of gasoline vehicles have focused on zero to 97 km/h acceleration rates and have concluded that peak power per kilogram is an appropriate single surrogate for acceleration capability. In this paper, statistical methods are used with data for 107 vehicles tested and reported by Consumers Union for 1986--1988 model years to estimate the determinants of contemporary gasoline vehicle acceleration capability under various conditions, adding new variables to the statistical tests reported by others. Like previous studies, this analysis determined that power and weight provide the most information about acceleration capability. Using a model formulation unlike other studies, this study found that engine displacement also provides statistically significant improvements in explanation of 0-48, 0-97, and 48-97 km/h acceleration times. The coefficients of the equations imply that the use of smaller displacement engines, holding peak power constant, diminishes start-up and 0-97 km/h acceleration capability. A separate equation is estimated to illustrate the effects of advanced engine technologies on displacement, controlling for power. This equation is used in conjunction with the acceleration equations to illustrate a method of estimating performance-equivalent engine substitutions when engine technologies change. Transmission type was important for start-up acceleration, with automatic-transmission-equipped vehicles beingmore » significantly slower than stick-shift-equipped vehicles. Fuel injection was found to significantly improve start-up acceleration. Variables proxying aerodynamic-drag effects tended to be significant determinants of acceleration in the higher-speed equations, but not for start-up acceleration. Estimated aerodynamic drag effects indicated that drag slows down 0-97, 48-97, and 72-105 km/h acceleration of pickup trucks and sport utility vehicles more than passenger cars and vans.« less

Statistical methods are used with 107 vehicels whose fuel economy was presented and reported for five test types in a single publication by Consumers Union (CU) for 1986-88 vehicles. Standard loglinear statistical formulations are used with data from this and supplementary sources to develop coefficients estimating the percent fuel economy gain per percent change in engine/vehicle design characteristic. The coefficients are developed for the five different test conditions evaluated by CU and are compared with each other on the basis of attributes of the tests. The insights of engineering models are used to develop expectations regarding the shift in size of coefficients as driving cycles change. In both the engineering models and the statistical model, the effect of weight is estimated to be higher in urban driving than in highway driving. For two test categories - field tests and dynamometer tests - the benefits of weight reduction are statistically estimated to be greatest in urban driving conditions. The effect on idle fuel flow rate of designing vehicles to hold performance roughly constant by maintaining power per kg and/or displacement per kg is examined, and its implication for the size of the weight effect is simply approximated from Sovran's 1983 engineering test results. The fuel-economy-decreasing effect of the desire for performance is estimated to be somewhat larger in the statistical analysis than in the NAS study, when engine technology is held constant.

This paper explores the impact of US emission controls and fuel economy improvements on the global warming potential (GWP) of new light-duty vehicles. Fuel economy improvements have reduced the GWP of both passenger cars and light-duty trucks by lowering the per mile emissions of carbon dioxide (CO{sub 2}). Further GWP reductions have been achieved by emission standards for criteria pollutants: carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NO{sub x}). The GWP of a criteria pollutant was calculated by multiplying the emission rate by a relative global warming factor to obtain a CO{sub 2} equivalent emission rate. Both CO{sub 2} and criteria pollutant emission rates per vehicle have decreased substantially for new light-duty vehicles over the period from 1968 to 1991. Over that period, the GWP from CO{sub 2} was reduced by almost 50% in new vehicles by improving fuel economy. In that same time period, the GWP from criteria pollutants from new vehicles was reduced with emission controls by from 80% to 90% depending on the global warming time frame of interest. Consequently, total reductions in the GWP of new passenger cars and light-duty trucks have been on the order of 55 to 75 percent compared to precontrol (before more » 1968) new vehicles. However, the reduction in GWP caused by emission control of criteria pollutants has been larger than the reduction caused by improved fuel economy (i.e., reduced CO{sub 2}). The contribution of criteria pollutants to the GWP of precontrol new vehicles was substantial, but their contribution has been reduced significantly due to US emission controls. As a result, the contribution of criteria pollutants to global warming is now much less than the contribution of CO{sub 2} from fuel consumption. « less

Despite the significant decline in energy prices and the large budget deficit, the US government must maintain a well-balanced energy technology development programme ranging from basic science through to the demonstration of technical feasibility and technology transfer. Having technology in technical readiness before an energy price shock will moderate economic problems due to the price shock and thereby promote economic stability. Based on evolving knowledge about the relationships among energy prices, technology commercialization, and recessions and depressions, development of efficient energy technologies must be far better managed by government and the private sector during both normal economic growth and energy crisis.

Hypotheses concerning the micro- and macroeconomic effects of historically important fuel switches in the vehicles operating on the dominant U.S. transportation modes are statistically tested using nineteenth and twentieth century data. Estimates of annual rates of change of fuel switching are constructed using logistic curve models fitted to often sparse data on fuel use. The estimated annual rate of loss of market share of an old fuel is then shown to be positively and consistently correlated with five-year averages of declines in the rate of growth of the fleets of vehicles affected by ongoing fuel switch. Other statistical tests show that five-year average changes in the rate of growth of the quantity of vehicles positively correlate with five-year average changes in the rate of growth of macro-economic activity when the affected vehicles are directly (through production and sales) responsible for a large share of macroeconomic activity (real GNP). The vehicle types shown to have this effect are locomotives from 1885–1915 and automobiles thereafter. The third set of tests supports an interpretation that the indirect effects of fuels switches, acting through their effects on the costs of transporting factors of production (both labor and physical inputs), have a significant and consistent GNP effect throughout the 1880–1980 period, even during the WWII-influenced period when the test for direct effects of automobiles fails. In case study discussion of each fuel switch it is shown that a pronounced drop in GNP growth occurs at the time when the important fuel switches are most rapidly being accomplished. Results of the statistical and case study analyses are compared to the author's prior research on vehicle engine innovation. The timing of peak rates of fuel switching and vehicle engine innovation are graphically shown to coincide for locomotives and automobiles from the 1880s to the 1980s. Further, the peak rates of fuel switching are graphically shown to occur when current real GNP relative to trend real GNP is declining and/or below the trend.

In the modeling of urban areas airline distance is often used as a proxy for travel time or distance. This practice has been justified by a high coefficient of determination (R2) between these variables in a random sample of pairs of traffic zones. The ratio of travel distance to airline distance has been used as a measure of network efficiency and called the route factor. This exercise uses hypothetical examples to examine network structure, congestion, and trip production as determinants of route factors and of R2 values of travel distance regressed on airline distance.

An econometric model of air pollution for an intraurban location (the Chicago area) is constructed and estimated. The model treats employment and population as simultaneously determined. Exogenous variables are selected to represent transportation infrastructure investments resulting primarily from federal and state decisions. The exogenous variables account for the relative services provided by highways, commuter railroads, rail rapid transit, waterways, and airports. The employment location equations appear to be considerably more successful than those in previous studies. These equations indicate that waterway availability constrains the locational options of most major industrial air polluters; that highway accessibility is a more influential factor in industrial than services location choices; that rail rapid transit accessibility is more important to services than industrial locations; and that major airports attract light industrial development. The success of the employment location equations reflects the importance of disaggregating intraurban modes of transport and of adding to urban location models the local effects of interurban modes of transport such as water and air.

The air pollutant carbon monoxide (CO) is produced by incomplete combustion in motor vehicles, space heating, industrial processes, and incineration. Current research indicates that higher density residential developments, because they lead to reduced demand for fuels for home heating and transportation, tend to lower total carbon monoxide emissions. However, it is in these same areas that concentrations of CO are the highest because of the density of emitters. Since carbon monoxide standards specify maximum allowable concentrations rather than emissions, they tend to deter further development in locations where concentrations are already high - i.e., high density downtown areas. This deterrent effect contributes to greater total emissions of carbon monoxide; hence, it may be desirable to devise a means of controlling the public's risk of exposure to high CO levels in downtown areas without deterring new center city residential development. In protecting the public from the risk of exposure to damaging levels of carbon monoxide, two approaches are possible; the pollutant's concentration may be lowered by traffic management measures or the public's rate of exposure may be reduced through urban design features. The present emphasis on traffic management stresses improving the flow and reducing the level of traffic, goals that aremore » extremely costly to achieve in downtown areas. This paper examines ways to reduce risk of exposure by the physical design of new downtown residential developments. The concept is not a novel one, having been successfully implemented in industry to provide occupational health and safety.« less

The paper examines water use in industrial production as a cause of geographical clustering of major air polluting industries. It shows that the majority of particulate and sulfur oxide emissions in the State of Illinois is emitted by industries using more than five billion liters of water per establishment per year. It also shows that the majority of industrial air pollutants is emitted within urban areas which are on water bodies with high and consistent volumes of water available. These and other results cited in the paper imply that any policy directly or indirectly promoting geographic dispersal as a means of reducing air pollution concentrations and population exposure rates is likely to be limited in effectiveness. It is suggested that such a policy can be effective only if at least one of two specified conditions is met. However, these conditions do not, by themselves, insure the success of such a policy. Finally, it is observed that the conjunction of air pollution with industrial water use indicates that much closer attention is needed to the relationship between air pollution and water pollution policies.