Anant Vyas

ANALYSIS OF TECHNOLOGY OPTIONS TO REDUCE THE FUEL CONSUMPTION OF IDLING TRUCKS

Long-haul trucks idling overnight consume more than 838 million gallons (20 million barrels) of fuel annually. Idling also emits pollutants. Truck drivers idle their engines primarily to (1) heat or cool the cab and/or sleeper, (2) keep the fuel warm in winter, and (3) keep the engine warm in the winter so that the engine is easier to start. Alternatives to overnight idling could save much of this fuel, reduce emissions, and cut operating costs. Several fuel-efficient alternatives to idling are available to provide heating and cooling: (1) direct-fired heater for cab/sleeper heating, with or without storage cooling; (2) auxiliary power units; and (3) truck stop electrification. Many of these technologies have drawbacks that limit market acceptance. Options that supply electricity are economically viable for trucks that are idled for 1,000--3,000 or more hours a year, while heater units could be used across the board. Payback times for fleets, which would receive quantity discounts on the prices, would be somewhat shorter.

LIFE-CYCLE ENERGY SAVINGS POTENTIAL FROM ALUMINUM-INTENSIVE VEHICLES.

The life-cycle energy and fuel-use impacts of US-produced aluminum-intensive passenger cars and passenger trucks are assessed. The energy analysis includes vehicle fuel consumption, material production energy, and recycling energy. A model that stimulates market dynamics was used to project aluminum-intensive vehicle market shares and national energy savings potential for the period between 2005 and 2030. We conclude that there is a net energy savings with the use of aluminum-intensive vehicles. Manufacturing costs must be reduced to achieve significant market penetration of aluminum-intensive vehicles. The petroleum energy saved from improved fuel efficiency offsets the additional energy needed to manufacture aluminum compared to steel. The energy needed to make aluminum can be reduced further if wrought aluminum is recycled back to wrought aluminum. We find that oil use is displaced by additional use of natural gas and nonfossil energy, but use of coal is lower. Many of the results are not necessarily applicable to vehicles built outside of the United States, but others could be used with caution.

Estimation of Fuel Use by Idling Commercial Trucks

This paper uses the recently published 2002 Vehicle Inventory and Use survey to determine the number of commercial trucks in the categories that are most likely to idle for periods of more than 0.5 h at a time. On the basis of estimated numbers of hours for both overnight idling by sleepers and long-duration idling by all size classes during their workdays, the total fuel use by idling trucks is estimated to be more than 2 billion gallons per year. Workday idling is determined to be a potentially much larger energy user than overnight idling, but data are required before any definitive conclusions can be reached. Existing technologies can reduce overnight idling, but development may be needed to reduce workday idling.

Potential of Plug-In Hybrid Electric Vehicles to Reduce Petroleum Use: Issues Involved in Developing Reliable Estimates

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.

Scenario analysis of hybrid class 3-7 heavy vehicles.

The effects of hybridization on heavy-duty vehicles are not well understood. Heavy vehicles represent a broader range of applications than light-duty vehicles, resulting in a wide variety of chassis and engine combinations, as well as diverse driving conditions. Thus, the strategies, incremental costs, and energy/emission benefits associated with hybridizing heavy vehicles could differ significantly from those for passenger cars. Using a modal energy and emissions model, they quantify the potential energy savings of hybridizing commercial Class 3-7 heavy vehicles, analyze hybrid configuration scenarios, and estimate the associated investment cost and payback time. From the analysis, they conclude that (1) hybridization can significantly reduce energy consumption of Class 3-7 heavy vehicles under urban driving conditions; (2) the grid-independent, conventional vehicle (CV)-like hybrid is more cost-effective than the grid-dependent, electric vehicle (EV)-like hybrid, and the parallel configuration is more cost-effective than the series configuration; (3) for CV-like hybridization, the on-board engine can be significantly downsized, with a gasoline or diesel engine used for SUVs perhaps being a good candidate for an on-board engine; (4) over the long term, the incremental cost of a CV-like, parallel-configured Class 3-4 hybrid heavy vehicle is about %5,800 in the year 2005 and

Batteries for Electric Drive Vehicles: Evaluation of Future Characteristics and Costs Through a Delphi Study

3,000 in 2020, while for a Class 6-7 truck, it is about

Impacts of Charging Choices for Plug-In Hybrid Electric Vehicles in 2030 Scenario

7,100 in 2005 and

Trade-off between PHEV fuel efficiency and estimated battery cycle life with cost analysis

3,300 in 2020; and (5) investment payback time, which depends on the specific type and application of the vehicle, averages about 6 years under urban driving conditions in 2005 and 2--3 years in 2020.

Impacts of plug-in hybrid electric vehicles on the electric power system in the western United States

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.

Fuel Consumption of Heavy-Duty Trucks: Potential Effect of Future Technologies for Improving Energy Efficiency and Emissions

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.