Source: adapted from J.D. Chapman (1989) Geography and Energy: Commercial Energy Systems and National Policies, New York: Longman Scientific & Technical.
An ideal transportation mode would have the potential to move at a high speed and consume low levels of energy per unit transported. There are significant differences between speed, energy costs, mode, and type of loads (freight and passengers). Since economies of scale play a crucial role in freight transportation, this is reflected in its lower levels of energy consumption per unit transported for the modes able to maximize them. Overall, transport operators try to seek a compromise between speed (returns in overcoming distance) and energy (costs in overcoming distance).
The lowest energy consumption levels are associated with bulk freight traveling at slow speed, while high energy consumption levels correspond to passengers or freight being carried at high velocities. The first corresponds to a compromise of energy over speed, while the second is a compromise of speed over energy. The compromise for supersonic planes was so disadvantageous that commercial services (Concorde) were abandoned in 2003.