Fuel Sources Processes
Liquid petroleum fuels (gasoline, diesel, kerosene, jet fuel, bunker fuel) Conventional oil fields (ground and shore-based). Non-conventional sources (tar sands) Refining
Liquid synthetic fuels Natural gas, coal Gasification
Biodiesel Oil seed crops Esterification, hydrogenation
Ethanol Grain crops Saccharification and distillation
Sugar crops (cane) Distillation
Advanced biodiesel Biomass from crops or waste products Gasification
Compressed natural gas (CNG) Natural gas Gasification
Electricity Coal, gas, petroleum, nuclear, renewables (hydro, wind) Electric generator (source dependent)
Hydrogen Natural gas Reforming, compression
Electricity Electrolysis
Direct production using other sources High temperature process
Source: adapted from IEA/OECD (2009) Transport, Energy and CO2: Moving toward sustainability. Paris: International Energy Agency.
Fuels Production Processes
Each fuel has specific sources and processes related to its transformation. The more marginal the sources and the more complex the processes, the higher the price and scarcity. A major challenge concerns the sustainability of the energy sources as well as of the processes leading to the creation of fuels that can be used by transportation.