29-11-2012, 04:58 PM
Hybrid Electric Vehicle Technology Assessment: Methodology, Analytical Issues, and Interim Results
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Introduction
This report presents the interim results of the Argonne National Laboratory (ANL) Hybrid
Electric Vehicle Technology Assessment (HEVTA). Hybrid electric vehicles, or HEVs, are
vehicles with drivetrains that combine an electric drive (including electric motor and some form
of electricity storage) with a refuelable power plant (e.g., an internal combustion engine). This
combination is capable of significantly improving vehicle efficiency (see Box 1). Toyota’s Prius
and Honda’s Insight cars are both HEVs, the first commercial examples.
A full technology assessment (TA) examines the effects on society of introducing a new
technology or expanding the use of an existing technology, including a full range of costs and
benefits. This assessment focuses particularly on the energy impacts and costs of HEVs. The
focus is on the individual vehicle. We do not attempt to project the impacts of alternative
scenarios when large numbers of HEVs gradually penetrate the vehicle fleet.
Description of the Vehicles Evaluated
The vehicles are midsized passenger cars, with the interior space of such cars as the
Chrysler Intrepid and Ford Taurus and the external dimensions of the slightly smaller Chrysler
Cirrus and Chevrolet Malibu. The current versions of the Intrepid and Taurus weigh about
1,418 kg (3,125 lb); the 2010 CV versions will weigh about 1,225 kg (2,767 lb). The “gliders”
(bodies without drivetrains) are projected to weigh about 922 kg (2,029 lb) in 2010. The HEV
versions will have gliders that are 5% heavier to account for structural reinforcement needed to
accommodate heavier drivetrain components.
Results
If compared to recent widely publicized studies that evaluate hybrid vehicle technology, this
one is unique with respect to the variability in types of hybrids, potential levels of performance,
and variety of driving cycles evaluated. It is narrow in the sense that it emphasizes cost only,
ignoring issues of emissions of criteria pollutants and the rich variability of consumer
preferences. Thus, it evaluates only the critical aspect of the potential marketability of hybrids.
The results are encouraging enough to recommend that examinations of their value for purposes
in addition to saving fuel for the owner are important, and could make a significant difference to
market success. For example, there might be a change of consumer valuation of a capability for
all-electric operation in an emergency, in light of the terrorism of September 11. Thus, this study
has some strengths and weaknesses that readers should be aware of. Wider reading on the
attributes of hybrids is recommended, but this study does complement others available.
With regard to the focus of this study – costs – the findings imply that research to reduce
dollar cost per unit of performance of electric drive components remains highly desirable. Thus,
the aggressive research goals of DOE – which if successful would drop costs to a level where
hybrids would be attractive on a net cost basis only – remain important. In our analysis, we do
not see such costs naturally emerging from market forces. Without any cost reduction
breakthroughs, we estimate that parallel “mild” hybrids should be within striking distance of
widespread marketability after several years of experience in producing the vehicles, and after
production and sales reach hundreds of thousands of vehicles. It is easy to imagine “niche
market” success of such hybrids based on factors other than cost that are important to consumers
and society. However, it is difficult to imagine widespread displacement of the conventional
vehicle at the costs that we estimate, unless (as we discuss in the report) fuel prices rise
considerably from levels of the last decade, and remain high. The latter alternative is less
desirable than achievement of cost-for-performance breakthroughs through continuing research
and development of drivetrain components. Specifics on our results follow.