Why is ethanol used in fuels?
Adding ethanol to gasoline increases the octane number – a measure of the fuel’s resistance to pre-ignition or engine “knock.” As well, ethanol contains oxygen, which allows for cleaner and more complete combustion. This in turn helps the environment. Developing, producing and retailing ethanol fuels also generates important new activities in rural regions and creates new markets for midwest grains. How does ethanol benefit the environment? Relative to gasoline, ethanol fuels reduce greenhouse gas (GHG) emissions that contribute to climate change. Ethanol is made from plants, which absorb carbon dioxide (CO2) during their growth. On a full fuel cycle (i.e. from plant growth to use of the fuel in a vehicle), a 10 percent ethanol-gasoline blend reduces GHG emissions by up to 4 percent if the ethanol is made from grains, and up to 8 percent if it is made from cellulosic biomass. Blends with 85 percent ethanol (E-85) can reduce emissions by 60-80 percent. Can ethanol fuels be used year-rou
