(64a) Food and Fuel: The Technical Potential of Biofuels in the United States Using Land Efficient Animal Feeds
AIChE Annual Meeting
2010 Annual Meeting
Sustainable Engineering Forum
Sustainable Biomass Feedstock Production and Supply for the Emerging Biorefinery Industry
Monday, November 8, 2010 - 8:30am to 8:55am
Despite the potential for biofuels to displace petroleum in the transportation sector, several concerns remain regarding land use issues. It is believed that there is not enough land available for both food and fuel production, and therefore large-scale biofuel production would cause adverse land use change such as deforestation. We introduce a separate approach, wherein current cropland is intensely managed to either produce both food and fuel or to increase food production, allowing land to be freed for biofuels. Cover crops can be grown on the same land as corn or soybeans, increasing the amount of stover removed and providing a fiber source for ruminants. In addition, protein recovery from early harvest hays can displace soybean production, while pretreating switchgrass or corn stover with ammonia pretreatments can displace traditional forages in cattle diets. Likewise, biofuel production can be performed on idle land or Conservation Reserve Program land.
In this study, the theoretical maximum amount of biofuel produced on current cropland without affecting overall food production is considered. Current fiber, energy, and protein needs for human consumption, animal feed, and exports are met. This study suggests that over 50% of current US gasoline consumption can be displaced by biofuels grown on current cropland in the United States. The large volume of biofuel produced is due to intensive harvesting of corn land, which includes grain, stover, and cover crops. New animal feeding technologies also contribute to increased biofuel production. This result is consistent across multiple sensitivity scenarios, with the largest changes being due to changing crop yields and the loss of corn land or cover crops. Net soil organic carbon increases in this scenario; however, nitrate leaching is greater than if little to no biofuels are produced. Greenhouse gas emissions are reduced by 670 Tg CO2-eq/yr, which is over 10% of current U.S. emissions.