Idaho's ethanol fuel industry, historically at the mercy of shifting energy tides, recently got a shot in the arm from three pieces of federal legislation.

The Clean Air Bill recently signed by President Bush after months of congressional wrangling requires the use of oxygenated fuels such as ethanol.Under the federal budget agreement, small ethanol producers will be eligible for a 10-cents-per-gallon tax credit for up to 15 million gallons of ethanol produced each year. Congress also extended federal production incentives through 2000 but reduced the size of the incentive from 6 cents to 5.4 cents per gallon.

And the 1990 Farm Bill requires the Commodity Credit Corp. to make 15 million bushels of otherwise virtually unmarketable corn available to ethanol plants at a discount.

Under the Clean Air Act, all gasoline sold in designated "carbon monoxide non-attainment areas," where air pollution is a problem, will be required to contain a certain percentage of oxygenated fuel, at least during the four winter months, starting Nov. 1, 1992.

Regionally, the Salt Lake City-Ogden and Spokane, Wash. areas sometimes have been designated non-attainment areas by the Environmental Protection Agency.

Ethanol is made primarily from the fermentation of such food stock as corn, wheat and barley, but potato process byproducts are the main source in Idaho.

The state now has only two ethanol production facilities, both operated by J.R. Simplot Co., in Caldwell and Heyburn. But Ethanol Marketing Inc. of Boise has proposed building a $30 million ethanol-fish food manufacturing plant in Lewiston.

The proposed Lewiston plant would use 18,000 bushels of cereal grain per day.