Introducing Bioenergy for a Possibly More Sustainable Agriculture

To make agriculture truly sustainable, the United States would need to overhaul several factors in energy consumption, but probably any effort at all is good effort. According tot he ERS (Economic Research Service) a department under the USDA, ethanol is the leading bioenergy fuel used in commercial agriculture. Derived from corn, ethonol is produced through industrial fermentation, chemical processing and distillation. While that doesn't sound very sustainable, neither is processing crude oil, so it's a step in the right direction.

The ERS put out a report on the use of bioenergy sources used in industrial farming. The overview is as follows:

• Rising fossil fuel prices and policy changes, including the passage of the Energy Independence and Security Act (EISA) of 2007, have created an environment where research development and investment in renewable energy sources have gained new momentum.


• Although most bioenergy production currently comes from agricultural crops such as grains, oilseeds, and sugar, research is increasingly focused on cellulosic sources of biomass such as wood and perennial grasses, use of which would expand the range of potential feedstocks.


• In the United States at this time, ethanol (produced mainly from corn) is the largest source of bioenergy used as a fuel additive or substitute for petroleum fuel, while biodiesel (made from vegetable oils and fats) provides a smaller share of bioenergy.


• The rapid increase in grain-based ethanol production and the potential use of cellulosic materials as an ethanol feedstock affects agricultural markets, local communities, consumer prices, and environmental quality.

Addressing each point in order:

The Energy Independence and Security Act (H.R. 6) is an omnibus energy policy law that consists mainly of provisions designed to increase energy efficiency and the availability of renewable energy.

The use of perennial grasses would be one of the most renewable resources possible to use, as they grow quickly and can be used as a cover crop for off-season plots, plots under rotation, or plots needing fixes of nutrients, utilizing otherwise fallow land.

Ethanol may not be the best choice ever, but it might be better than nothing. If the plan is to use renewable grasses with high celluloid counts (as opposed to wood), the efficiency of it could be dramatic.

The office for the U.S. Department of Energy, Energy Efficiency & Renewable Energy discusses the differences between using sugar / starch feedstocks vs. cellulosic feedstocks suited to ethanol production:

• Agricultural residue—crop residues such as wheat straw and corn stalks, leaves, and husks


• Forestry residue—logging and mill residues such as wood chips, sawdust, and pulping liquor


• Grasses—hardy, fast-growing grasses such as switchgrass grown specifically for ethanol production


• Municipal and other wastes—plant-derived wastes such as household garbage, paper products, paper pulp, and food-processing waste


• Trees—fast-growing trees such as poplar and willow grown specifically for ethanol production

These feedstocks have many advantages over starch- and sugar-based feedstocks. They are much more abundant and thus can be used to produce more substantial amounts of ethanol to meet U.S. fuel demand. They are waste products or, in the case of trees and grasses grown specifically for ethanol production, can be grown on marginal lands not suitable for other crops. Less fossil fuel energy is required to grow/collect them and convert them to ethanol (see Energy Balance of Ethanol), and they are not human food products.

While the total benefits or disadvantages are being discussed, the idea that a more renewable resource is being considered to fuel machinery for food-related energy leans toward a more efficient sustainable agriculture.

Photo credit: PRWatch.org