Impacts of U.S. biofuels mandates on environmental and energy security.

摘要

Congress passed the Energy Policy Act of 2005 and the Energy Independence and Security Act (EISA) of 2007 to reduce dependency on foreign oil by increasing the use of biofuels. EISA mandates 36 billion gallons of biofuel production in 2022, representing an increase of 118% in eight years. Existing and new farmland are expected to be employed to produce corn and other feedstock necessary to fulfill the biofuel mandate. There is little research on the potential environmental impact on water resources of meeting the ESIA biofuel mandates.;The objectives of this EISA study were twofold. First, the study measured the economic and environmental impact of nitrogen runoff on nation-wide water resources from crop production to meet the EISA 2022 biofuel mandates. Second, the study evaluated the potential effectiveness of EISA 2022 mandates on energy security due to replacing oil with biofuels to meet the energy needs of the transportation sector.;The study used the SPARROW modeling method to estimate nitrogen fluxes in the Mississippi River basins based on production required to meet the EISA 2022 biofuels mandate. The scenarios results show that biofuel production can result an increase of nitrogen flux to the northern Gulf of Mexico from 270 to 1742 thousand metric tons, that is an increase from 21% to more than 100% from the total nitrogen flux estimated by the EPA, (2011). Using all cellulosic (hay) ethanol or biodiesel to meet the 2022 mandate is expected to significantly reduce nitrogen flux however it requires approximately 25% more land than the land needed in EISA specified 2022 scenario. The estimated environmental economic cost of producing 36 billion gallons of ethanol using corn feedstock to meet the EISA 2022 mandate is estimated to be ;One of the main objectives of EISA is to promote energy independence by mandating that U.S. transportation fuel contain domestically produced biofuels, mainly ethanol. However, basic supply and demand forces make the probability remote that the EISA 2022 mandated biofuel production of 36 billion can be used domestically. If the U.S. policy objective is to replace imported oil with domestic sources of energy, then it would be more efficient to use locally produced fossil fuels such as natural gas to power motor vehicles, rather than to pursue the biofuel mandate. On the other hand, if the objective is to reduce the consumption of fossil fuels, then improving the efficiency of cars engines would yield better results. While is it unlikely that the U.S. will stop producing ethanol (Ethanol is used as a MTBE substitute to oxygenate gasoline), investing in higher ethanol blends does not seem to be an efficient solution to energy security.