Why is burning biofuel in car engines carbon neutral compared to burning gasoline from oil?
The burning of biofuel is SUPPOSED to be carbon neutral.
Ethyl alcohol may be derived from oxidation of sugars and cellulose; the fermentation of sugar to give ethyl alcohol may be represented in the balanced equation:
Because the sugar derives from green plants, which use solar energy to fix carbon dioxide, the carbon dioxide released to the environment represents only a marginal increase in carbon dioxide concentrations.
Of course, the machinery used to harvest the sugar cane (or what have you), and the material used to fertilize your next crop, represents a significant energy expenditure. The amount of arable land is also finite, and less than you would imagine, and a significant proportion of this must be devoted to food production. The use of biomass to make alcohols for fuel production is thus not a panacea.