Fuels to Generate Motion

A fuel is a liquid, solid or gaseous product used to generate heat, in the heat and electricity generation sectors, or motion in the mobility sector. In this glossary article, we refer to fuels that are used to generate motion.

Fuels to generate motion are defined as chemical substances whose energy content is utilized in technical systems to generate force or create propulsion, usually by combustion or other means of converting energy.

Fuels are distinguished as follows:

  • Fuel to generate motion: a substance used for direct combustion in a combustion engine, as in automotive engineering. There are essentially three types of fuel to generate motion:
    • Solid fuels (e.g. coal, biomass)
    • Liquid fuels (e.g. jet fuel, gasoline, diesel fuel, biodiesel/FAME)
    • Gaseous fuels (e.g. natural gas, biogas, avgas)
  • Fuel to generate heat: a liquid, solid or gaseous product used to generate heat

While liquid fuels to generate motion are highly flammable at room temperature, natural gas only becomes flammable at 600°C and under high pressure.


Classic fuels to generate motion, such as jet fuel, gasoline and diesel fuel, are produced from crude oil through fractional distillation in oil refineries. Besides these, there are alternative fuels such as bioethanol and rapeseed oil, created by alcoholic fermentation, transesterification or in oil mills, for example.

Beyond “natural” components, additives may be mixed in. These additives serve various functions, especially to improve properties, e.g. to increase knock resistance, improve cold starting, and clean the intake system.


A physical comparison of the calorific values (kWh/cbm) of fuels to generate motion shows that the fuel consumption (e.g. in liters per 100 km) benefits of certain fuels to generate motion are not based on their energy content per kg, but on their higher density and correspondingly higher weight per liter.

In gases, energy content depends strongly on the pressure. The range of a vehicle is determined among other things by the efficiency of its power units, the volume of the tank, and the energy stored in it.


As a resource-poor country, Germany, for example, has to import most of its fuels to generate motion. Crude oil comes mainly from Russia, the North Sea (primarily from the offshore production fields of the Netherlands and the United Kingdom), and North Africa. Natural gas also comes from Russia and the North Sea. Natural gas is produced in Germany, but not in sufficient quantities, so that most of the demand must be covered by imports from Russia and Norway. An exception to this are biofuels, which are also produced domestically, especially biodiesel from rapeseed and bioethanol from cereals, and therefore only imported in small quantities.


The tax rate depends on the type of fuel to generate motion. At this time, diesel fuels are taxed at lower rates than gasolines in Germany, and natural gas for the propulsion of vehicles is also taxprivileged.

Status: December 2015
All information subject to change. Errors and omissions excepted.