Clean fuel

Clean fuel
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Methods and techniques

Clean fuel is a type of fuel or power source that can be an alternative to fossil fuels[1]. Definitions of clean fuel vary by jurisdiction. In general, all fuel used in vehicles different than gasoline and diesel can be considered as clean fuel[2]. The term of clean fuel is often used interchangeably with the term alternative fuel, clean-burning fuel or non-conventional fuel.

Shrinking reserves of fossil fuels and danger of environmental pollution from their combustion were reasons for developing environmentally friendly, energy efficient and economically viable energy technologies[3]. Using clean fuels aims to reduce the emission of chemical compounds to the atmosphere. Among general pollutants are nitrogen oxides (NOx), sulfur dioxide and carbon oxides especially one of the greenhouse gases - CO2[4].

Types of clean fuels[edit]

The search for clean fuels has indicated a long list of substances which can be an alternative to gasoline and diesel. The main criteria for alternative fuels are cleaner burning than fossil fuels, emitting less pollution to the atmosphere, and if the fuel is obtained from renewable biomass sources it should reduce dependence on nonrenewable fossil fuels[5]. Nonetheless, alternative fuel, does not necessarily derive from a source of renewable energy. Based on the above criteria most significant clean fuels are distinguished[6]:

  • alcohols including methanol and ethanol, are considered as a replacement or supplement component for gasoline,
  • vegetable oils,
  • biodiesel which refers to an ethyl or methyl esters of fatty acids obtained from vegetable oils or animal fats,
  • gaseous fuels including natural gas, liquefied petroleum gas (LPG) and hydrogen,
  • ethers which are especially considered as additive component for fuel,
  • electric/hybrid/fuel cell vehicles,
  • future fuels including for example biodiesel produced from nonfood products, synthetic fuel, and cellulosic fuel.

Most of the legal regulations as examples of clean fuels list; natural gas including compressed natural gas (CNG) and liquefied natural gas (LNG), electricity, biofuels, hydrogen, synthetic and paraffinic fuels, liquefied petroleum gas (LPG)[7].

Due to The U.S. federal tax code, "clean-fuel" vehicles are motor vehicles fueled by natural gas, liquified petroleum gas, liquified natural gas, electricity, hydrogen and any other fuel that consists of at least 85% alcohol or ether[8].


  1. Directive on the deployment of alternative ..., (2014), article 2(1),
  2. Ramadhas A.S., (2016), p.8
  3. Ramadhas A.S., (2016), p.8
  4. Dell. R.M.c, Rand D.A.J., (2004), p.32
  5. Ramadhas A.S., (2016), p.8
  6. Ramadhas A.S., (2016), p.10-16
  7. Directive on the deployment of alternative ..., (2014), article 2(1)
  8. Gerrard M.B., (2007), p.574


Author: Angelika Marzecka