AutoTechInsight
Alternative fuels—CNG, LPG, and ethanol
Increasing concerns regarding air pollution, climate change, and depleting oil resources are bringing alternative automotive fuels to the forefront. In the search for alternative sources of propulsion, researchers around the world have developed capable competencies in areas such as electrification, alternative fuels, hybridization, hydrogen, and nitrogen. Success in alternative fuels aims to hasten the move away from the conventional, hydrocarbon-powered internal combustion engine (ICE) technology. Various types of alternative fuels would be required to gradually transit into replacement of gasoline and diesel as sources of combustion. According to the US 1992 Energy Policy Act (EPA), alternative fuels for vehicles are categorized as ethanol, biodiesel, electricity, hydrogen, methanol, natural gas (NG), and propane/liquefied petroleum gas (LPG). This report focuses on the most common alternatives to traditional automotive petrochemical-based liquid fuels, such as CNG, LPG, and ethanol and their application in fuel systems of vehicles with gross vehicle weight (GVW) less than 6 tons.
Both CNG and LPG have emerged as cost-effective and more environmentally friendly fuel types. CNG- and LPG-powered vehicles emit about 20% less carbon dioxide (CO2). In the case of CNG, NG has a more favorable ratio of hydrogen to carbon than gasoline, which means CO2 emissions are reduced by about one-quarter. For LPG vehicles, the environmental benefits are noticeable, since the mixture of butane and propane emits up to 15% less CO2 and up to 80% less NOx compared with conventional vehicles, according to Opel. However, ethanol-based fuel systems had the highest adoption rate among all alternative fuel systems in 2019 and occupied 83% of the market of alternative fuel systems and will continue to be the highest in 2026. CNG-based fuel systems are expected to witness consistent growth in 2019–26.
