Suggested Citation:
Lipman, Timothy E. and Mark A. Delucchi (2011) "Comparing Greenhouse Gas Emissions" chapter 6 in Sustainable Transportation Energy Pathways: A Research Summary for Decision Makers. Institute of Transportation Studies, University of California, Davis, 133 - 170

We turn now to comparing the environmental impacts of our alternative fuel / advanced vehicle pathways. Reducing greenhouse gas (GHG) emissions from vehicles and fuels is one key to lessening transportation’s contribution to the climate change problem. This chapter presents much of what is known about the relative emissions of GHGs from battery, fuel cell, and plug-in hybrid electric vehicles versus conventional internal combustion engine vehicles.

We first give some background on the issue of GHG emissions and their climate impact, and review previous research. We then discuss how GHG emissions from electric vehicle (EV) fuel cycles are estimated, before reviewing and comparing recent estimates of GHG emissions from the fuel cycles of various types of EVs. (Note that researchers generally distinguish emissions related to the life cycle of fuels and energy used to power the vehicle—the fuel cycle—from emissions related to the life cycle of the vehicle and the materials it is made from—the vehicle life cycle. In this chapter we focus mainly but not exclusively on fuel-cycle emissions, because there has been relatively little work on vehicle life-cycle emissions.) We next examine the potential for EVs to rapidly scale up to meet the climate challenge, and fi nally we discuss key uncertainties, areas for further research, and conclusions.