Background

Aviation is a rapidly growing source of GHG emissions. Mitigating these is complicated by the extreme technical requirements of passenger aircraft, the effect of international treaties and federal law governing aviation, and the rapidly changing landscape related to travel, especially international travel. Sustainable Aviation Fuels (SAF, sustainably produced fuels that substitute for petroleum aviation fuel and reduce GHG emissions or other environmental impacts) are one of the most important tools available for reducing the emissions from aviation. While SAF has been under development and small-scale testing for many years, commercial-scale deployment is a comparatively new phenomenon and many questions about the real-world impact of these fuels remain. At the same time, SAF is eligible to receive policy incentives under certain alternative fuel policies, notably the U.S. Renewable Fuel Standard (RFS) and California’s Low Carbon Fuel Standard (LCFS). In addition, the U.S. federal government has announced a SAF Grand Challenge, which targets an ambitious near-term goal of 3 billion gallons of SAF per year by 2030, on the way to meeting all aviation fuel demand with SAF with 50% lifecycle GHG intensity savings by 2050. As SAF is poised to increase its market presence, more information on trade-offs between aviation and on-road use of the most commercially mature technology, as well as how the introduction of SAF may impact alternative fuel uptake more generally, given policy targets, is needed to inform policy. In short, steps needed to ensure that alternative aviation fuels are also sustainably low carbon at scale and benefit communities.

The UC Davis Policy Institute for Energy, Environment, and the Economy, in collaboration with other UC Davis researchers specializing in air quality analysis, and an external modeler from GAMS Development Corp., is undertaking an analysis of two key questions:  air quality trade-offs between fuel use as SAF or renewable diesel on-road, and likely outcomes of policy scenarios under an LCFS that involves SAFs in terms of LCFS compliance fuel mix and credit pricing.

This project is currently underway. Check back for updates or contact Dr. Colin Murphy (cwmurphy AT ucdavis.edu) with questions about the research.