An alternative fuel vehicle is a motor vehicle that runs on alternative fuel rather than traditional petroleum fuels (petrol or petrodiesel). The term also refers to any technology (e.g. electric cars, hybrid electric vehicles, solar-powered vehicles) powering an engine that does not solely involve petroleum. Because of a combination of factors, such as environmental and health concerns including climate change and air pollution, high oil-prices and the potential for peak oil, development of cleaner alternative fuels and advanced power systems for vehicles has become a high priority for many governments and vehicle manufacturers around the world.
Vehicle engines powered by gasoline/petrol first emerged in the 1860s and 1870s; they took until the 1930s to completely dominate the original "alternative" engines driven by steam (18th century), by gases (early 19th century), or by electricity ( 1830s).
Hybrid electric vehicles such as the Toyota Prius are not actually alternative fuel vehicles, but through advanced technologies in the electric battery and motor/generator, they make a more efficient use of petroleum fuel. Other research-and-development efforts in alternative forms of power focus on developing all-electric and fuel cell vehicles, and even on the stored energy of compressed air.
An environmental analysis of the impacts of various vehicle-fuels extends beyond just operating efficiency and emissions, especially if a technology comes into wide use. A life-cycle assessment of a vehicle involves production and post-use considerations. In general, the lifecycle greenhouse gas emissions of battery-electric vehicles are lower than emissions from hydrogen, PHEV, hybrid, compressed natural gas, gasoline, and diesel vehicles.
Current deployments
, there were more than 1.49 billion motor vehicles on the world's roads, compared with approximately 159 million alternative fuel and advanced technology vehicles that had been sold or converted worldwide at the end of 2022 and consisting of:
Over 65 million flex fuel automobiles, motorcycles and light duty trucks by the end of 2021, led by Brazil with 38.3 million and the United States with 27 million. Over 26 million plug-in electric vehicles, 70% of which were battery electric vehicles (BEVs) and 30% of which were plug-in hybrids (PHEVs). China had 13.8 million units, Europe 7.8 million, and the United States 3 million. In 2022, annual sales exceeded 10 million vehicles, up 55% relative to 2021. 24.9 million LPG powered vehicles by December 2013, led by Turkey with 3.93 million, South Korea (2.4 million), and Poland (2.75 million). 24.5 million natural gas vehicles by the end of 2017, led by China (5.35 million) followed by Iran (4.0 million), India (3.05 million), Pakistan (3 million), Argentina (2.3 million), and Brazil (1.78 million). In 2015, 2.4 million units were sold. Over 13 million hybrid electric vehicles as of 2019. 5.7 million neat-ethanol only light-vehicles built in Brazil since 1979, with 2.4 to 3.0 million vehicles still in use by 2003. and 1.22 million units as of December 2011. 70,200 fuel cell electric vehicles (FCEVs) powered with hydrogen by the end of 2022. South Korea had 29,500 units, the United States 15,000, China 11,200, and Japan 7,700. In 2022, annual sales amounted to 15,391 vehicles. Hydrogen FCEV sales as a percentage of market share among electric vehicles (BEVs, PHEVs and FCEVs) declined for the 6th consecutive year.
Mainstream commercial technologies
Flexible fuel
A flexible-fuel vehicle (FFV) or dual-fuel vehicle (DFF) is an alternative fuel automobile or light duty truck with a multifuel engine that can use more than one fuel, usually mixed in the same tank, and the blend is burned in the combustion chamber together. These vehicles are colloquially called flex-fuel, or flexifuel in Europe, or just flex in Brazil. FFVs are distinguished from bi-fuel vehicles, where two fuels are stored in separate tanks. The most common commercially available FFV in the world market is the ethanol flexible-fuel vehicle, with the major markets concentrated in the United States, Brazil, Sweden, and some other European countries.