American Petroleum Institute

NET ENERGY ANALYSIS OF ALCOHOL FUELS
 N PUBL 4312

Annotation

Obtaining an adequate supply of energy is one of the most important issues facing the nation today. Of particular concern is the rising cost of petroleum imports and the high dependence of the United States upon imported oil to balance its energy budget. One of the methods proposed to alleviate this problem is the manufacture of liquid fuels from domestically grown biomass, i.e. plant material.

There has been considerable debate in both the popular and technical press regarding the merits of manufacturing liquid fuels from biomass. Much of this controversy has centered on the manufacture of ethanol (or ethyl alcohol) from grain. It is hoped that the results of this study will help resolve some of the controversy surrounding the question of the feasibility of manufacturing liquid fuels from biomass.

The objective of this study is to determine the net fuel consumption for the production of liquid fuels from biomass. Consideration of the relative combustion efficiencies of gasoline vs. alcohols, beyond the scope of this report, has been addressed elsewhere.*

Five different technologies were considered in this study. Three of these technologies manufacture ethanol, while two have methanol (and fuel gas) as their primary product. The three ethanol processes considered consume sugar cane, corn, and corn stover as raw materials.

The manufacture of ethanol from com was selected for study because this process is frequently proposed and because its merits are most frequently debated in the press. The technology is well established and is commercially practiced. The manufacture of ethanol from com is similar to its manufacture from other grains (i.e., wheat, barley, and milo). Com is the least expensive of the grains suitable for ethanol manufacture in the United States.