关键词：生物燃料；生物质；农业分析；生物能源
摘 要：The U.S. Renewable Fuel Standard (RFS2) is a strategic response to concerns under the Energy Independence and Security Act (EISA) of 2007 about petroleum fuel supplies and environmental sustainability (EPA 2012). RFS2 regulations mandate specific amounts of renewable fuels to be blended into gasoline and diesel. The renewable fuels also need to emit fewer greenhouse gases than the displaced petroleum. In 2012, the target is for 9of all fuel will be from renewable sources, or a minimum of 15.2 billion gallons of renewable fuel. By 2022, the target is for 36 billion gallons of renewable fuel to be blended into gasoline and diesel and of that amount, 16 billion gallons derived from cellulosic biofuels. While some advanced biofuel will be refined from forest, crop, and urban residues, this paper focuses on the patterns of farmers choices regarding dedicated perennial lignocellulosic energy crops. Throughout this paper we use the term perennial as shorthand for warm season grasses such as those in the genus Panicum or Miscanthus, or short rotation tree crops such as those in the genus Populus or Salix. We focus on choices about these perennial crops because two thirds of the mandated advanced biofuels are expected to be converted at biorefineries from perennials (USDA 2010). RFS2 establishes the goals, but not mechanisms for achieving them. Mechanisms and incentives, however, are embedded in other legislation and programs. For example, the 2008 Farm Bill created the Biomass Crop Assistance Program (BCAP) that is designed to entice farmers to plant and deliver biomass feedstock to biorefineries and electrical plants. The effectiveness of this new program, however, has yet to be fully explored (Aguilar et al. 2011). In 2011, the program received over 40 project area proposals, exceeding the available funding, suggesting increasing adoption, or at least exceeding expectations of policymakers.