 With a small amount of redesign, gasoline-powered vehicles can run on ethanol concentrations as high as 85% (E85), the maximum set in the United States and Europe due to cold weather during the winter, or up to 100% (E100) in Brazil, with a warmer climate.Ethanol has close to 34% less energy per volume than gasoline, consequently fuel economy ratings with ethanol blends are significantly lower than with pure gasoline, but this lower energy content does not translate directly into a 34% reduction in mileage, because there are many other variables that affect the performance of a particular fuel in a particular engine, and also because ethanol has a higher octane rating which is beneficial to high compression ratio engines.For this reason, for pure or high ethanol blends to be attractive for users, its price must be lower than gasoline to offset the lower fuel economy.