Gasohol

One of the suggested methods to reduce the need to import petroleum is to produce fuel from agricultural crops. Gasohol, a mixture of 90% unleaded gasoline and 10% ethyl alcohol, can be used in autos without making carburetor adjustments. Whether better or worse mirage results is debatable; most results so far indicate it is worse compared to burning gasoline.

However, the crucial question is if a net energy gain results when gasohol rather than gasoline is used as fuel. Analyses of the energy costs of producing the ethyl alcohol component of gasohol take into account the energy consumed in agricultural production and the subsequent cooking and fermentation processes that yield the alcohol.

Studies reported recently in Science indicate that about half of the agricultural energy cost is in the fuel to run the tractors and other machinery. Fertilizers and machinery production make up most of the rest. Much more energy is required to cook and distill the corn, sugar cane or other crop to be converted to fuel.

If petroleum is used as the energy source for all the processes that lead to the production of gasohol, the whole idea seems to be a loser, and that does not even take into account the energy required for irrigation, drainage or other projects that subsidize agricultural production.

Only if renewable energy sources can be used to produce gasohol can this fuel be considered as a solution to the petroleum problem even at latitudes where high yields of sugar and starch crops can be grown. In the north, agricultural biomass conversions to liquid fuel seem even more likely to be unprofitable.