Energy Crops: the sweet and the sour
Switchgrass, miscanthus, hybrid poplar - these are just the first three plants I think of when I hear the term "energy crop." But I heard of a new one a few weeks ago when I attended a conference (story fortcoming) about commercializing biobased chemicals and fuels. Let me introduce you to a very big "weed" called Arundo donax.
While most energy crops produce a few tons of dry biomass per acre, Arundo - a tall bamboo-like reed - can produce several. Like switchgrass, it is a perennial. Like Kudzu, however, it is self-propagating and possibly horribly invasive.
It looks like the huge plant (it's a weed when it grows where it isn't wanted, like in California), may become a lot more well-known in biofuels circles. Chemtex will use it, along with wheat straw, in its first commercial facility in Crescentino, Italy. This plant is already humming, and commercial ethanol production is expected to begin early next year.
Chemtex plans to construct another ethanol plant in eastern North Carolina. Through a USDA program intended to promote rural development through the cultivation of energy crops, the company was offered a $99 million loan guarantee to plant "high yielding energy grasses, including miscanthus and switchgrass." According to a fascinating look at Arundo cultivation - and eradication - by the Associated Press, it looks like the giant weed may also be part of the mix.
Meanwhile, a much sweeter crop, a high-sugar variety of sorghum, may be edging its way into Brazil's famous sugar-growing regions. Plant biotech firm Ceres, and agribusiness firm Syngenta plant to run test plots of hybrid sweet sorghum destined for ethanol production. The press release says that Brazil's ethanol industry has created a shortage of sugar cane, and the country views sorghum as a strategic crop.
While Arundo would be harvested just for its biomass, sorghum is usually grown for its seed which is used in animal feed.
Arundo donax is a giant reed from Asia. Credit: USDA