One of the issues behind the blend wall for ethanol in the motor gasoline supply is the increased fuel economy standards that were passed at the same time as the Energy Independence and Security Act of 2007 (EISA). Biodiesel is not subject to blend wall concerns, but that could become an issue in the longer term.One of the issues behind the blend wall for ethanol in the motor gasoline supply is the increased fuel economy standards that were passed at the same time as the Energy Independence and Security Act of 2007 (EISA). A more fuel-efficient vehicle fleet reduces the overall amount of gasoline consumed and effectively lowers the 10 percent blend benchmark. Biodiesel is not subject to blend wall concerns, but that could become an issue in...