"Federal policy has played a key role in the emergence of the U.S. biofuels industry. Policy measures include minimum renewable fuel usage requirements, blending and production tax credits, an import tariff, loans and loan guarantees, and research grants. This report focuses on the mandated minimum usage requirements--referred to as the Renewable Fuel Standard (RFS)-- whereby a minimum volume of biofuels is to be used in the national transportation fuel supply each year. It describes the general nature of the RFS mandate and its implementation, and outlines some emerging issues related to the sustainability of the continued growth in U.S. biofuels production needed to fulfill the expanding RFS mandate, as well as the emergence of potential unintended consequences of this rapid expansion. Congress first established an RFS with the enactment of the Energy Policy Act of 2005 (EPAct, P.L. 109-58). This initial RFS (referred to as RFS1) mandated that a minimum of 4 billion gallons be used in 2006, and that this minimum usage volume rise to 7.5 billion gallons by 2012. Two years later, the Energy Independence and Security Act of 2007 (EISA, P.L. 110-140) superseded and greatly expanded the biofuels blending mandate. The expanded RFS (referred to as RFS2) required the annual use of 9 billion gallons of biofuels in 2008 and expanded the mandate to 36 billion gallons annually in 2022, of which no more than 15 billion gallons can be ethanol from corn starch, and no less than 16 billion must be from cellulosic biofuels. In addition, EISA carved out specific requirements for 'other advanced biofuels' and biomass-based biodiesel."
CRS Report for Congress, R40155