The document discusses several alternative fuels including biodiesel, hydrogen, methanol, ethanol, electricity, liquified petroleum gas, and biomass. Biodiesel is produced from vegetable oils and animal fats and can be blended with petroleum diesel. Hydrogen is the most abundant element and its environmental impact depends on how it is produced. Methanol is produced from natural gas and ethanol is produced by fermenting biomass. Electricity is readily available but electric vehicles are currently expensive. Liquified petroleum gas is a byproduct of petroleum refining and biomass is plant matter used to generate electricity or heat but produces air pollution.