Alternative Energy: New Sugarcanes To Deliver One-Two Energy Punch

Agricultural Research Service (ARS) scientists, in cooperation with the Louisiana Agricultural Experiment Station (LAES) and the American Sugar Cane League, USA (ASCL), have already released three new varieties of "energy sugarcane." They're called that because of their high stalk contents of sugar and fiber, which could eventually serve as complementary ethanol feedstocks.

Raw-sugar processors now burn the fiber to generate heat that powers stalk-crushing and sugar-crystallization processes, notes Edward Richard, who leads the ARS Sugarcane Research Unit in Houma, La. The extracted sucrose sugar is sold for consumption or converted into ethanol. However, Richard anticipates that biorefineries will use the fiber as well, once technologies for converting cellulose into ethanol become economically feasible.

The three new energy sugarcanes--one high fiber/low sucrose and two high sucrose/high-fiber varieties--were released in April 2007 by ARS, LAES and ASCL as part of a cooperative breeding program. The releases also reflect ARS' push to exploit region-specific crops as feedstocks that will sustain localized production of biobased fuels and energy.

Corn, especially that grown in the Midwest, is a staple feedstock for ethanol production. But in southern Louisiana, soil conditions are more amenable to sugarcane and sweet sorghum. Sugarcane also offers a key processing advantage over corn-based ethanol production: Cane sugars needn't be derived from starch using cooking steps and enzymes. Rather, the sugar can be directly fermented into ethanol as soon as the sugar is extracted from stalks.

Richard estimates an acre planted to one of the three energy sugarcanes could yield nearly 1,240 gallons of ethanol using both the sugar and fiber. To extend sugarcane's growing and processing season and production range further to the north, his lab also is developing cold-tolerant varieties of the crop.