Assessing the Emissions Reduction Potential of Biofuels in California

Abstract

While efforts by California to reduce emissions for individual vehicles are known to the general public, emission reduction efforts involving heavy-duty vehicles are less prominent. Biofuels are an alternative fuel source that has been proposed and partially implemented to reduce emissions related to transportation. Renewable diesel is one such type of biofuel that can be used as a drop-in fuel for heavy-duty vehicles, such as trucks. This specific biofuel can reduce vehicular emissions within California, which has a sizable biofuel capacity, without changing multiple infrastructure sectors. When compared to petroleum diesel, renewable diesel has been demonstrated to have 65% less carbon intensity in addition to 4.1% fewer NOx emissions and 4.2% fewer CO emissions (California Air Resources Board, 2024a; Kelly and Ragatz, 2018). This paper is an introductory assessment of the usage of renewable diesel to reduce emissions in heavy-duty vehicles. As a biofuels-based solution for the purpose of reducing emissions, the authors propose the expansion of renewable diesel within California via increasing the number of renewable diesel fueling stations in regions within the state that currently lack them. This solution would be implemented alongside the expansion of production, which would be done separately outside the scope of this project. This potential solution and its associated challenges, benefits, and feasibility considerations are discussed alongside the merits and issues of renewable diesel itself.