Biofuels are associated with lower greenhouse gas emissions but have greater aggregate environmental costs than gasoline. ~ ecologists Jörn Scharlemann & Bill Laurance
Biomass was man’s main energy source for the many millennia before industrialization. Even after, ethanol found favor for powering vehicles.
American industrialist Henry Ford was an enthusiastic ethanol proponent. His Model T could run on it or gasoline.
Ethanol is ethyl alcohol (C2H5OH) used as engine fuel. Grain alcohol for guzzling and other medicinal applications is made by fermentation. Industrial ethanol is had via hydration of ethylene. Both come from sugary crops such as beets, sugarcane, and corn.
Increased fuel demand during the 1st World War boosted US ethanol production, but the introduction of leaded gasoline and the increasingly inexpensive refining of crude oil took the crops out of the gas tank.
The 1970s oil shocks brought Brazil back to ethanol, but it was not until the 21st century that the US got back into biofuel in a big way, thanks solely to government mandates and subsidies.
Growing crops for vehicular rather than dietary consumption has played a significant role in food price inflation. Further, the environmental dilemma associated with cultivation is compounded by trying to grow both food and fuel.
The energy content of ethanol is only 65% that of gasoline. Low power density and the acreage required to grow fuel stock alone makes ethanol an ill-advised energy source. But biofuel gets worse when considering its environmental impact beyond growing the biomass to derive it. Ethanol processing produces airborne heavy metals, copious amounts of wastewater, and other pollutants.
Rivers and waterways in Brazil have been biologically dead since the 1980s owing to biofuel effluents. Ethanol is ~1/3rd of Brazil’s automotive fuel.
Whereas America feeds its biofuel frenzy with corn, Brazil grows sugarcane to make its ethanol. For its energy inputs sugarcane delivers a whopping 8 times output than does corn. But sugarcane doesn’t grow well in the US Midwest. So American farmers are subsidized to grow an insensible fuel.