Renewable Transportation Fuel for California's Electric-Drive Vehicles

California has enacted a number of policies that incentivize the use of advanced vehicle technologies and fuels to help reduce petroleum usage, air pollution and greenhouse gas emissions. These include the Pavley greenhouse gas emissions standards, the Low Carbon Fuel Standard (LCFS), the Zero Emission Vehicle (ZEV) regulation and various incentives for alternative fuel infrastructure. In addition, California has set an economy-wide goal of reducing greenhouse gas (GHG) emissions 80% below 1990 levels by 2050, which will likely require radical changes in the transport sector. Some of the most promising strategies to help the state meet its ambitious goals in transportation rely on electric-drive technologies: such as Plug in Hybrid Electric Vehicles (PHEVs) and Battery Electric Vehicles (BEVs) and hydrogen powered Fuel Cell Vehicles (FCVs).

While electric-drive vehicles can be significantly more efficient than conventional internal combustion engine vehicles (ICEVs) (FCVs can be 2-3x more efficient and BEVs can be 3-4x more efficient), efficiency alone will not be enough to accomplish the required deep cuts in GHG emissions. Today electricity and hydrogen fuel have a carbon intensity comparable to gasoline, (California gasoline has 96 gCO2e/MJ, average California electricity is around 112 gCO2e/MJ and hydrogen from produced from natural gas can be between 90-110 gCO2e/MJ). With growing numbers of vehicles, it will not be possible to meet long-term GHG emissions goals with higher vehicle efficiency alone. To realize the full potential of electric-drive vehicles, fuel carbon intensity must be reduced and low-carbon resources, such as renewables should used to produce electricity and hydrogen. Existing state regulations for the electric sector and hydrogen infrastructure set targets for renewable content.

In this paper we explore the potential and the challenges associated with using renewable resources for hydrogen and electricity transportation fuels in California. In particular, we develop and analyze a range of scenarios for introducing electric-drive vehicles fueled by renewable fuels out to the year 2050. This research builds on previous work presented at NHA (2008 and 2009). We use an hourly model of the California electricity grid to investigate strategies for electric-vehicle recharging and integrating renewables into the grid and a detailed geographic model of hydrogen fuel production, distribution and refueling infrastructure. Wind and solar are among the most promising renewable resources in California, but they are intermittent and must be utilized when available. Using large amounts of intermittent renewables poses an integration challenge for the electricity system. This study analyzes detailed hourly data for wind and solar availability in different regions of the state to explore whether using these resources to make transportation fuels that are stored in a battery or as hydrogen can help alleviate some of these challenges. We estimate the total potential for using renewable resources to produce fuel for electric and hydrogen vehicles in California. Alternative pathways are compared with respect to cost, GHG emissions, energy use and transition issues. Finally, we discuss the potential for synergies and integration between renewable transportation fuels and the remainder of the state energy system.