Sensitivity of United States Emissions Reductions
to Market Penetration Variables of Alternative Vehicles

Belinda Chen
Bachelor's of Arts in Environmental Studies
May 2002

Technology is often touted as the solution to many of our environmental problems, but how much can we depend on new vehicle technologies to mitigate our impact on the atmosphere and air quality? This thesis examines a handful of the most promising vehicle technologies, specifically: hybrid electric vehicles, hydrogen fuel cell vehicles, and battery electric vehicles. The purpose is to study the technological potential of alternative vehicles to affect aggregate emissions. Although this potential could be partially dependent upon various policies, the intent is not to determine which policies would be necessary to achieve a certain level of reductions. Rather, the focus is to explore the plausible maximum effect that technology-oriented transportation policies might ha ve on the timing and magnitude of emissions reductions. This effect is highly sensitive to the rate of market penetration, which is determined by a host of technological, social, economics, and political factors, but previous studies have not generally accounted for this uncertainty. Low-emitting technologies that penetrate at a fast rate will obviously reduce aggregate emissions more than technologies that penetrate at a slower rate. Other penetration-related factors, especially level of saturation and time of introduction, would also influence the extent of emissions reductions.

Using historical penetration rates of automotive technologies to create a set of penetration rate scenarios of alternative vehicle technologies, future emissions of greenhouse gases and air pollutants can be calculated in an age-specific model of vehicles in the United States. My findings indicate that the selection of technology will prove to be a significant factor in potential reductions. The rate of market penetration and the time technologies are introduced will also play an important role. Although transportation-related measures are unlikely to contribute to near-term emissions reductions such as those included in the Kyoto Protocol, a plausible scenario with conservative assumptions indicates that light-duty vehicle emissions could be reduced by 50% from the reference case within 40 years. Progress in emissions reductions could be further accelerated with the help of more aggressive policy to expedite introduction of alternative vehicles and encourage their adoption.