Can gasohol play a key role in weaning the United States from dependence on Mideast oil? It depends on whose study you read. For several years a lively debate has raged over the the virtues or vices of gasohol, the mixture of one part alcohol to nine parts gasoline.
It is one of a number of half-technical and half-ideological fire fights that have broken out in the course of the "Great Energy Policy War" declared following the Arab oil embargo of 1973-74, which continues unabated today.
The gasohol flap is instructive because it clearly illustrates a number of difficulties besetting US attempts to arrive at a sensible and coherent energy policy. Perhaps the most serious of these stem from the fact that energy has become a statistical battleground.
Repeatedly in the area of energy, where facts tend to be limited and the complexity great, the conclusions of many technical studies proceed from the basic assumption that the analyst chooses. And these assumptions, often as not, are rooted in ideology rather than objective fact.
Take the case of gasohol. The controversial analyses have centered around the question of whether more energy, particularly petroleum, would be consumed in the production of alcohol than would be saved by using it as a fuel or as chemical feedstock.
From the beginning, the gasohol debate has been primarily political. Support for the idea has centered in the agricultural community. Farmers, particularly in the corn belt, have seen alcohol fuel as a way to become more energy independent and as a new market for their products. Resistance to the idea has tended to center in the oil and automotive communities.
One group of experts, some with oil company ties, have published reports concluding that it takes more fossil fuel to produce alcohol than is saved by burning the alcohol produced. At the same time, other experts, often with agricultural affiliations, have published equally detailed studies that arrive at the opposite conclusion.
The result has been considerable uncertainty among policymakers. As a gasohol brief prepared by the National Conference of State Legislatures concludes: "It appears that additional research will be necessary before gasohol is widely used."
This conclusion was picked up as ammunition by the opponents of gasohol. It was severely criticized by gasohol's proponents. The result was a spate of more detailed studies. For instance, an analysis done by two University of Nebraska scientists, W. Scheller and B. Mohr, was entitled "Gasoline does, too, mix with alcohol." It came up with a favorable energy ratio. They achieved this by subtracting the energy in the crop residue from the total energy input -- an assumption justified only if the crop residue were burned to produce energy.
Two Mobil Oil Corporation scientists, however, came to the opposite conclusion. Using current technology, they said, gasohol was a net energy loser. Going even further, they argued that even if it could be produced at a net energy gain it would be extremely expensive, costing more than $5 a gallon.
Buried in the Mobil analysis were two important assumptions. They used energy consumption figures for existing, inefficient distilleries rather than the more-efficient units on the drawing boards. They also slipped in the assumption that gasohol mileage was 2.7 percent less than that of unleaded gasoline.
Meanwhile, Nebraska scientists were conducting a driving test which that showed that gasohol gets 7 percent better mileage than gasoline. The approach used in this road test has been criticized not only by gasohol opponents but by the congressional Office of Technology Assessment. It turns out that energy balance calculations are quite sensitive to mileage assumptions. If gasohol is assigned a higher mileage, its energy balance relative to gasoline is easily positive. With a significantly lower mileage, the balance turns negative. With equal mileage, the calculation can go either way.
Lab experiments have tended to show a lower mileage for gasohol than for gasoline. Many driving tests have suggested a higher mileage but are considered less reliable. As the debate matured, some experts began questioning just how important the net energy question was to begin with.
Finally, some scientists began analyzing the various analyses. In the first such assessment, a group of University of Illinois researchers concluded that the results of past studies were "strongly dependent on assumptions about use of crop residues and the miles-per-gallon rating a gasohol. In terms of total nonrenewable energy, gasohol is close to the energy break-even point. On the other hand, in terms of petroleum or petroleum-substitutable energy, gasohol is an unambiguous energy producer. . . ."
Still the controversy continues, almost with a life of its own. Last January a Louisiana State University scientists concluded that the production of alcohol from sugar cane could be either a net energy producer or consumer depending on whether crop residues or fossil fuels were used for the industrial processing.
Last month the DOE issued a report done by TRW researchers that they hope will put an end to the net energy debate. They looked at the production of alcohol from corn, sorghum, and municipal wastes; with process heat being supplied by coal, residual oil, natural gas, crop residues, and electricity; and , assuming that gasohol mileage is 4 percent less, equal to, and 4 percent better than unleaded gasoline.
For an efficiently designed alcohol plant located in Illinois they find a small net energy gain in all cases and an "impressive" petroleum gain.