‘The Grass Giant’ alter ego: Miscanthus
Move over corn, giant Miscanthus is on track to take over your domestic renewable ethanol production commitments. Actually a hybrid of two species of Miscanthus, this 12-foot-tall grass requires fewer chemicals to grow than our favorite yellow-kernelled vegetable but produces at least 1,000 more gallons of ethanol per hectare than both corn’s grain and cellulose ethanol production combined. The reasons behind the increased ethanol production is both a growing season nearly four months longer than that of corn and Miscanthus’s ability to convert 1 to 2 percent of the solar energy it absorbs into biomass (most plants, like corn, have a 0.1 solar-energy-to-biomass conversion).
Researchers at the University of Illinois have calculated that replacing one-fifth of the gasoline used by the U.S. in a year with renewable ethanol would require about 12 million hectares, or 9.3 percent of the U.S. cropland, to be converted to Miscanthus. Achieving the same ethanol production with corn grain would require 31 million hectares of land.
Miscanthus has benefits beyond ethanol production. As a perennial crop, it only requires annual harvesting, not planting. This results in lower labor costs and, without the need for yearly tilling on the crop land, soil erosion and stored carbon release rates are substantially decreased. Conservationists also applaud the grassland habitat Miscanthus stands provide for birds and other animals. Plus, as a sterile hybrid, Miscanthus poses little to no invasive risk to adjoining ecological communities. Finally, because Miscathus is highly efficient at capturing nitrogen, the use of fertilizers on the plants is not necessary, and so nutrient runoff into waterways is minimal.