THE FEASIBILITY AND POTENTIAL ENVIRONMENTAL BENEFITS OF ALTERNATIVE FUELS FOR COMMERCIAL AVIATION

摘要

High fuel prices and the environmental effects of aviation are motivating strong interest in alternative jet fuels. In the first months of 2008, prices for jet fuel were at record levels and concerns regarding the environmental effects of aviation on air quality and global climate change were strong. Since 2006, the Commercial Aviation Alternative Fuels Initiative (CAAFI) has brought together the government, industry, academia, and non-profits to investigate and promote alternative aviation fuels. To date, CAAFI has held two major conferences and has facilitated tests of possible alternative jet fuels. As a result of CAAFI's efforts, new specifications for jet fuels are being drafted that may enable the commercial introduction of alternative jet fuels. A forthcoming study investigates ten potential alternative jet fuels (alternatives in terms of both feedstock and fuel composition are considered). Within the next decade, the production potential of alternative jet fuels without policy incentives is on the order of ten percent of expected consumption. The emissions of particulate matter and precursors that affect air quality are significantly lower for many of the fuels considered in the study. The life-cycle carbon dioxide emissions of the alternatives range from roughly zero to many multiples of conventional fuel. This range depends on the feedstock, the conversion technology, the availability of opportunities for geologic carbon capture and sequestration, and any indirect land use changes that result from the creation of the biomass feedstock. Lastly, ultra-low sulfur jet fuel can provide an immediate means for reducing emissions that degrade air quality while also paving the way for future alternative jet fuels.