Biofuels and the Environment

About Biofuels

Biofuels are derived from renewable biological materials such as ethanol from corn starch, corn stover, perennial grasses, woody biomass, and algae, and diesel from soybeans. Currently available biofuels are made from sugar crops (sugarcane, sugarbeet); starch crops (corn, potatoes); oilseed crops (soybean, sunflower, rapeseed); and animal fats. Sugar and starch crops are converted through a fermentation process to form bioalcohols, including ethanol (the most widely used), butanol, and propanol. Oils and animal fats can be processed into biodiesel. Most vehicles built after 2000 can use gasoline-ethanol blends containing up to 15% ethanol (by volume). Currently there are about 3,500 fueling stations in the U.S. that offer E-85 fuel, most of which are in the upper Midwest.

Replacing fossil fuels with biofuels has the potential to reduce some undesirable environmental impacts of fossil fuel production and use, including conventional and greenhouse gas (GHG) pollutant emissions, exhaustible resource depletion, and dependence on unstable foreign suppliers. Demand for biofuels could also increase farm income. Biofuel production and use has drawbacks as well, including land and water resource requirements, air and ground water pollution. Depending on the feedstock and production process, biofuels can emit even more GHGs than some fossil fuels on an energy -equivalent basis.

Biofuel Reports to Congress

In 2007, Congress enacted the Energy Independence and Security Act (EISA) with the stated goals of "mov[ing] the United States toward greater energy independence and security [and] to increase the production of clean, renewable fuels." By these goals, EISA revised the Renewable Fuel Standard (RFS) Program, created under the 2005 Energy Policy Act and administered by the EPA, to increase the volume of renewable fuel required to be blended into transportation fuel to 36 billion gallons per year by 2022. Section 204 of EISA directs EPA, in consultation with the U.S. Departments of Agriculture and Energy, to assess and report every three years to Congress on the environmental and resource conservation impacts of the RFS Program.

The reports:

• Analyze impacts across the entire life cycle of biofuels, including the production and transportation of feedstocks and the production, distribution, and use.
• Assess environmental impacts, including air, water, and soil quality.
• Assess resource conservation impacts, including soil conservation, water availability, land use changes, and ecosystem health and biodiversity.
• Evaluate environmental and agricultural impacts resulting from the growth and use of cultivated invasive plants.

The first report to Congress was completed in 2011 and assessed the environmental and resource conservation impacts associated with increased biofuel production and use (EPA/600/R-10/183F). The overarching conclusions of this first report were:

1. The environmental impacts of increased biofuel production and use were likely negative but limited in impact.
2. There was a potential for both positive and negative impacts in the future.
3. EISA goals for biofuel production could be achieved with minimal environmental impacts if best practices were used and technologies advanced to facilitate second-generation biofuel feedstocks (corn stover, perennial grasses, woody biomass, algae, and waste).

The second report to Congress was completed in 2018 and reaffirmed the overarching conclusions of the 2011 Report (EPA/600/R-18/195). The 2018 Report noted that the conditions of biofuel production and use that led to the findings of the 2011 Report had not materially changed (e.g., most biofuel production was still from corn ethanol) and that the production of biofuels from cellulosic feedstocks anticipated by both the EISA and the 2011 Report had not materialized. Noting observed increases in acreage for corn and soybean production in the period before and following implementation of the RFS2 Program, the 2018 Report concluded that the environmental and resource conservation impacts associated with land use change were likely due, at least in part, to the RFS and associated production of biofuel feedstocks.

The third report to Congress builds on the previous two reports, Biofuels and the Environment: First Triennial Report to Congress (2011) and Biofuels and the Environment: Second Triennial Report to Congress (2018). The Third report updates the previous assessments of the environmental impacts of the RFS Program and includes new analyses to estimate the separable effects of the RFS Program from the impacts of other factors that affect biofuel production and use more generally. The report concludes that the effect of the Renewable Fuel Standard Program varies with time and likely had modest negative impacts on many of the environmental effects reviewed in the report.

Publications

EPA Reports:

• U.S. EPA. Biofuels and the Environment: the First Triennial Report to Congress (2011 Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-10/183F, 2011.
• U.S. EPA. Biofuels and the Environment: The Second Triennial Report to Congress (2018 Final Report). U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-18/195, 2018.
• U.S. EPA. Biofuels and the Environment: Third Triennial Report to Congress (Final Report, 2024). U.S. Environmental Protection Agency, Washington, DC, EPA. 

Resources:

• Set Rule Website 
• Set Rule Regulatory Impact Analysis 
• RFS Program
• Model Comparison Exercise 
• 2010 Regulatory Impact Analysis