Assessing clean vehicle systems under constraints of freshwater resource

The development and deployment of clean vehicles bring great potential of reducing transportation greenhouse gas (GHG) emission and dependency on fossil fuels. The net GHG reduction through clean vehicle systems is tightly linked to the electricity grid mix (for electrical cars and plugin hybrids) and fueling strategy (for cars using alternative fuels). Natural resources may also pose constraints on clean vehicle system development, considering regional water scarcity and agriculture land availability. To understand these interrelationships and support decision making, we are developing a modeling framework to evaluate and project water and land demand from clean vehicle system development under different scenarios and ultimately optimize resource allocation to maximize GHG reduction. From both national and regional scale, this research evaluates a variety of clean vehicle technologies including renewable fuels and electrification to ensure that the combination of these technologies will reduce GHG emissions from a life cycle perspective. In addition, this research identifies and evaluates constraints posed by critical natural resources to meet clean vehicle targets in the U.S. For renewable fuel production, water resources and land will be critical. For low carbon electricity generation, the availability of wind, solar, biomass, geothermal, and land will significantly shape the composition of clean vehicle technologies in different regions. Overall, the goal is to make sure a net life cycle reduction in GHG emissions will be achieved under different scenarios of resource constraints. This paper summarizes data about water resources from both national and regional scale.