Estimating Nitrogen Load Resulting from Biofuel Mandates

Abstract

The Energy Policy Act of 2005 and the Energy Independence and Security Act (EISA) of 2007 were enacted to reduce the U.S. dependency on foreign oil by increasing the use of biofuels. The increased demand for biofuels from corn and soybeans could result in an increase of nitrogen flux if not managed properly. The objectives of this study are to estimate nitrogen flux from energy crop production and to identify the catchment areas with high nitrogen flux. The results show that biofuel production can result in an increase of nitrogen flux to the northern Gulf of Mexico from 270 to 1742 thousand metric tons. Using all cellulosic (hay) ethanol or biodiesel to meet the 2022 mandate is expected to reduce nitrogen flux; however, it requires approximately 25% more land when compared to other scenarios. Producing ethanol from switchgrass rather than hay results in three-times more nitrogen flux, but requires 43% less land. Using corn ethanol for 2022 mandates is expected to have double the nitrogen flux when compared to the EISA-specified 2022 scenario; however, it will require less land area. Shifting the U.S. energy supply from foreign oil to the Midwest cannot occur without economic and environmental impacts, which could potentially lead to more eutrophication and hypoxia.

Hydrologic and water quality impacts of biofuel feedstock production in the Ohio River Basin

“…Despite the ORB being an important basin for current and future biofuel feedstock productions, to date, limited studies explored the associated impacts on the basin water resources (Alshawaf et al ., ; Panagopoulos et al ., ). Alshawaf et al .…”

“…Alshawaf et al . () applied the SPARROW regression model for the entire Mississippi River basin to assess the land use needs and nitrogen flux to meet the 2022 biofuel target from increased production of hay, corn, and switchgrass. Panagopoulos et al .…”

“…Despite the ORB being an important basin for current and future biofuel feedstock productions, to date, limited studies explored the associated impacts on the basin water resources (Alshawaf et al, 2016;Panagopoulos et al, 2017). Alshawaf et al (2016) applied the SPARROW regression model for the entire Mississippi River basin to assess the land use needs and nitrogen flux to meet the 2022 biofuel target from increased production of hay, corn, and switchgrass.…”

“…Despite the ORB being an important basin for current and future biofuel feedstock productions, to date, limited studies explored the associated impacts on the basin water resources (Alshawaf et al, 2016;Panagopoulos et al, 2017). Alshawaf et al (2016) applied the SPARROW regression model for the entire Mississippi River basin to assess the land use needs and nitrogen flux to meet the 2022 biofuel target from increased production of hay, corn, and switchgrass. Panagopoulos et al (2017) applied SWAT for the Upper Mississippi, Ohio, and Tennessee Rivers basins to assess the changes in the rivers discharges and water qualities related to different levels of stover harvest and the inclusion of switchgrass and Miscanthus on marginal and nonmarginal lands.…”

Estimating Virtual Nitrogen Inputs to Integrated U.S. Corn Ethanol and Animal Food Systems

“…However, increased fuelrelated agricultural production also puts additional nutrientrelated stress on ecosystems. 12 The N impacts of food and biofuel systems have been studied separately, but the link between corn ethanol and animal food systems has not been considered in N studies. potential, energy, and water use impacts of corn ethanol are well-studied, 13−18 and researchers have found that consideration of ethanol coproducts has a significant impact on results and is essential to accurately estimate environmental impacts of corn ethanol production.…”