 |
Prof. Dr. Ibrahim Dincer
Director, Clean Energy Research Laboratory (CERL)
Professor of Mechanical Engineering
Department of Mechanical, Automotive and
Manufacturing Engineering
Faculty of Engineering and Applied Science
University of Ontario Institute of Technology
(UOIT)
|
A COMPARATIVE LIFE CYCLE ASSESSMENT OF ALTERNATIVE AVIATION FUELS
In this study, a comparative life cycle assessment of various alternative aviation fuels is conducted. The investigated fuels include: hydrogen, ammonia, methanol and ethanol, as well as bio fuels and jet fuels. The study present a well-to-wake approach in order to determine the overall life cycle of a passenger aircraft running on these conventional and alternative fuels. Although there are modifications required to fulfill the aviation fuel specifications for such alternative fuels, the long term viability and environmental sustainability make them attractive solutions for the future of aviation industry.
Currently, petroleum based fuels have better combination of accessibility, ease of handling, energy content, performance, and price for aviation industry. Therefore, these type of fuels are heavily used by the transportation sector including air, land, and sea. Nevertheless, limited nature, nonhomogeneous source distribution, fluctuating prices, and end use related emissions of fossil fuels have prompted most of the industries to look for other alternatives. The global aviation industry produces around 2% of all human induced CO2 emissions. Aviation is responsible for 12% of CO2 emissions from all transports sources, compared to 74% from road transport. Around 80% of aviation sourced CO2 emissions are emitted from flights of over 1,500 km, for which there is no practical substitute method of transportation. In 2015, the flights produced 770 million tonnes of CO2 in the world.
Aircraft fuels have additional requirements compared to land and sea transportation counterparts. Aircraft fuels, for instance, must not be affected by extreme temperature changes. Hydrogen and ammonia could be an alternative to traditional hydrocarbon fuels. They have zero or very minor GHG emissions during utilization in the aircraft. Potentially, hydrogen and ammonia can eliminate aviation industry’s reliance on limited fossil fuel sources with fluctuating prices. They can also decrease aviation industry’s influence on the anthropogenic greenhouse gas emissions drastically.
From the feedstock extraction or production to the final use in aircrafts, the fuel goes through multiple steps constituting its life cycle. At each of these steps, GHG emissions are likely to be produced. The total carbon foot print of the fuel is obtained by adding all these emissions together in a life cycle assessment (LCA) approach. Thus, to assess the emissions reductions from using alternative fuels, a comprehensive accounting must be conducted of all emissions across all steps of the fuel’s life cycle, from the field to the tank of the aircraft.
|
