Potential of clean liquid fuels in decarbonizing transportation – An overlooked net- zero pathway?

Muhammed Zafar Ali Khan*, Haider Ali Khan, Sai Sudarshan Ravi, James WG Turner, Muhammad Aziz*

*Corresponding author for this work

Research output: Contribution to journalReview articlepeer-review

15 Scopus citations


Despite the growing sales of electric vehicles and electrification as a means to alleviate the growing problem of climate change, it is largely overlooked that internal combustion engine-driven vehicles still account for 99.8% of the global transportation fleet. These vehicles pose a significant demand for liquid fuels, which is typically met by fossil fuels whose combustion is known to exacerbate the climate crisis. The COVID-19 pandemic significantly impacted the energy industry, particularly the transportation sector (aviation, maritime, and road transport), largely because of travel restrictions globally. While this period of relative inactivity had relatively reduced the climate impact, it also caused a severe economic crisis. Hence, travel restrictions cannot be viewed as means to solve transportation emissions. While moving towards alternative cleaner propulsion technologies to propel vehicles is a perfectly good strategy, the problem of running the legacy fleet in a carbon-neutral way could assist in decarbonizing the sector as a whole. This emphasizes that the need for sustainable and environment-friendly fuels is inevitable. This article discusses the potential of clean fuels in providing a net zero-carbon pathway that is largely overlooked and critically reviews the recent trends and advancements with clean fuel applications in aviation, marine, and road transportation. Altogether, promising future choices include ammonia blends with ethers, hydrogen, gasoline-ethanol-methanol ternary blends, methanol-to-gasoline, Fischer-Tropsch diesel and kerosene, and natural gas. The article also makes some recommendations on policy action that takes a balanced approach to address the climate crisis and have a meaningful impact on the environment.

Original languageEnglish (US)
Article number113483
JournalRenewable and Sustainable Energy Reviews
StatePublished - Sep 2023


  • Clean fuels
  • Decarbonization
  • e-fuels
  • Electrification
  • Net-zero energy pathway

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment


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