Why is burning biofuel in car engines carbon neutral compared to burning gasoline from oil?

1 Answer
Feb 12, 2017

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:

#C_6H_12O_6 rarr 2C_2H_5OH(l) + 2CO_2(g)uarr#

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.