Renewable Fuel Standard (RFS): Waiver Authority and Modification of Volumes [Updated August 3, 2020] [open pdf - 1MB]
From the Summary: "The Clean Air Act requires that transportation fuels contain a minimum volume of renewable fuel. This Renewable Fuel Standard (RFS) was established by the Energy Policy Act of 2005 (EPAct05; P.L. 109-58) and amended by the Energy Independence and Security Act of 2007 (EISA; P.L. 110-140). The RFS includes scheduled volume mandates that grow each year (starting with 9 billion gallons in 2008 and ascending to 36 billion gallons in 2022). The U.S. Environmental Protection Agency (EPA), which is responsible for administering the RFS, determines the annual volume after 2022. Within the overall RFS, there are submandates for advanced biofuels, including cellulosic biofuel and biomass-based diesel."
CRS Report for Congress, R44045
Congressional Research Service: https://crsreports.congress.gov/