The advantages and limitations of the U.S. ethanol industry have both become apparent during the current period of high petroleum prices. One advantage is that ethanol is cost-reducing as a gasoline additive and as a gasoline replacement using E85 (motor fuel blends of 85 percent ethanol and just 15 percent gasoline). However, corn supply limits ethanol's role in energy markets; ethanol-based corn demand will surpass exports when the 7.5 billion gallon Renewable Fuel Standard is fully implemented; and even if the Midwest were to secede from The Union, the entire Midwestern corn crop could only supply two-thirds of regional gasoline demand with ethanol. Clearly, a broader resource base and other processing technologies are needed if bioenergy is going to expand its role in the national energy scene.