development state of PEM cells demands caution in such assessments, and we see little basis for
them. In particular, fuel cells have a complex balance of plant,^61 a methanol reformer with
required gas cleanup to avoid poisoning the fuel cell’s catalysts, and a number of still-unresolved
O&M-related issues such as cathode oxidation and deterioration of membranes.EMISSIONS PERFORMANCEReductions in vehicular emissions are a key goal of programs to develop advanced technology
vehicles. In California, it is the only explicit goal, although other considerations, such as economic
development, are important. Furthermore, PNGV’s original name was the Clean Car Initiative.
The drive to ratchet down the emissions of new vehicles is highly controversial. One reason is
that most vehicular emissions come from older vehicles, or relatively new vehicles whose emission
controls are malfunctioning. Automakers have long argued that new control requirements that
raise the price of new vehicles have the effect of slowing new vehicle sales and, thus, reducing
fleet turnover-the primary source of improved fleet emissions (and fuel economy) performance.
Further, there is substantial disagreement about how much new controls will cost, and thus similar
disagreement about their balance of costs and benefits.
Each of the advanced vehicles examined by OTA have emission characteristics that are different
from current vehicles as well as from the baseline (business-as-usual) vehicles expected to enter
the fleet, if there are no new incentives for significant changes in vehicle technology. A number of
changes that will yield improvements to new vehicles’ emission performance, however, already are
programmed into vehicle development programs. Both the federal Clean Air Act and California’s
Low Emission Vehicle Program require significant improvements in the certified emission levels
allowable for new light-duty vehicles, as well as an extension of the certified “lifetime” of required
control levels from 50 thousand to 100 thousand miles. New requirements for onboard
diagnostics to alert drivers and mechanics to problems with control systems, more stringent and
comprehensive inspection and maintenance testing (including testing for evaporative emissions),
and expansion of certification testing procedures to include driving conditions that today cause
high emission levels should ensure that actual on-road emissions of average vehicles more closely
match the new vehicle certification emissions levels.
The Advanced Conventional vehicles will most closely resemble the baseline vehicles’ emissions
performance. By 2015, however, these vehicles will have direct injection engines-either diesel or
gasoline. These engines should have lower cold start and acceleration enrichment-related
emissions than conventional gasoline engines. This should have a positive impact on emissions,
although new regulations should force down such emissions even in the baseline case. A key
uncertainty about emissions performance for these vehicles is the performance of the NOX
catalysts, which currently remain under development. Another area of concern, for the diesels, is
particulate emissions performance; although new diesel designs have substantially reduced