The Aviation Fuel and the Passenger Aircraft for the Future - Bio Fuel, Synthetic Fuel

Author: Karunanidhi RAMACHANDRAN

Master Thesis


This work is a review and analysis of the advantages and disadvantages of alternative fuels - bio fuels and synthetic fuels - and the possibility to use them in air transportation. It has been shown that alternative fuels can be used in aircraft engines without modifications. Alternative fuels are applied to reduce green house gas emissions, but the reduction potential strongly depends on the source of the alternative fuel. There are great opportunities for alternative fuel production. However, large investments in new production plants would be necessary. Bio mass is the source for bio fuel. Also algae can be used as a source for bio fuel. Synthetic fuel is produced through the Fisher-Tropsch (FT) process. Synthetic fuel can be produced from coal, natural gas (also from bio mass) or even directly from water and CO2 with alternative energy. Synthetic fuels have almost the same performance as jet fuel. However, synthetic fuel from coal (CTL) or natural gas (GTL) leads to high CO2 emissions into the atmosphere. Sun to Liquid (STL) and Power to Liquid (PTL) methods even take CO2 out of the atmosphere during the production process (releasing the CO2 back again into the atmosphere in flight). Nevertheless, these methods are still in laboratory or demonstrator scale. Published test data about the certification of alternative fuels is given. Flight tests done with the alternative fuels are listed for further reference. Most importantly, the thesis provides some insight into the consequences of using alternative fuels in aviation with respect to aircraft design and aircraft performance as a function of fuel density and engergy content. Life cycle assessment (LCA) need to be carried out to find the exact level of the Green House Gas (GHG) emission level for alternative fuels. LCA results of alternative fuels are compared with results from an LCA of conventional jet fuel.