Sorghum syrup is about as traditional as it gets in rural America, particularly in the old South – where people still pour it over hot biscuits at breakfast just like they’ve done for hundreds of years – yum! Only now, they’re starting to pour it into their gas tanks, too. Well, not really, but almost!
During a summer in which the biofuels world has been rocked by huge headlines on other fronts, there is one alternative fuel source not exactly rotting away in the fields! Sorghum – and particularly sweet sorghum – seems finally prepared to emerge from behind the dense biomass shadows it casts with its giant 15-foot stalks!
Sweet sorghum – a resilient grass that can be grown on arid farmland and needing relatively little help in the way of irrigation, fertilizer or insecticides – is quietly gaining support around the world as a “smart biofuel” source. Unlike corn-based ethanol, which is said to use more energy to produce than it offers as an end product, sweet sorghum is now being touted by some studies as producing between four and eight times the energy input – with no affect on the food side of the debate.
Breakthroughs already have occurred in other countries – like India, where the Tata Industries conglomerate has teamed with the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) to construct a distillery producing 10,000 gallons of ethanol a day using sweet sorghum. Such efforts are being heavily supported in India because the grain portions of the crop can still be used for food production and animal feed. With that – and the fact it can grow in the poorest countries on earth – sweet sorghum is getting to be very sweet, indeed!
Sorghum has been known for years to be one of the most efficient crops with its unique ability to be drought-tolerant while converting solar energy to biomass. As a result, a “sorghum belt” has evolved from the upper Midwest to the Southwest states and along the Mississippi River Delta, with most of the grain – and also the stems and leaves – being used historically for livestock feeds. This year, an estimated 8.1 million acres are under cultivation in the U.S., according to the National Sorghum Producers (NSP) – most of it as grain sorghum or forage sorghum, varieties of the plant originally produced to serve the lucrative livestock market.
But things are changing, and the NSP and other sorghum promoters must be staying up nights to keep pace. On the energy front, grain sorghum already is a proven ethanol producer – demonstrating equal amounts of ethanol per bushel as corn but using only one-third the water and fertilizer. Forage sorghum is bound to be one of the future feedstocks of cellulosic ethanol, because the entire plant with its heavy biomass can be used – also with the same savings in water. And, because of its gluten-free nature, sorghum flour is growing in popularity as a health food product.
But sweet sorghum looms as the potential superstar, because it combines all of the unique talents listed above – plus a large volume of sugar that can be fermented and distilled into ethanol and other biochemicals before the cellulosic residue is used to make even more products. And here’s the clincher – as an annual plant, needing only four months to mature in warmer climates, two crops might be grown a year in certain areas!
Southeast Renewable Fuels LLC, of Fort Lauderdale, FL, is among the first to apply the technology in this country, with three sweet-sorghum-fueled plants in the works in South Florida – including one announced on July 29 with Seminole Electric Cooperative in Tampa that reportedly will be online by 2011. A second project is Louisiana Green Fuels, LLC in Lacassine, LA which will use an existing sugar cane facility to do double duty to produce sweet sorghum ethanol. Only a scattering of other firms have made the leap: BioDimensions is in the development phase of a sweet sorghum project in west Tennessee which has pulled together a highly skilled group of farmers, equipment manufacturers, and a local bottling company to produce ethanol from the juice and other high value chemicals from the bagasse; In Australia, a company called AgriFuels is beginning a project in southeastern Queensland; Canada’s Tectane Technologies reportedly has some projects in its pipeline; while Ceres Inc. is continuing research in the development of sweet sorghum as well as high-biomass sorghum seed varieties for commercial production.
A number of pilot projects are under way in places like China and Brazil, according to news reports – as well as a number of research tracts at ag-related universities everywhere. For example, Oklahoma State University is experimenting with new ways to express sugar juice in the field to reduce transportation costs. Meanwhile, a United Sorghum Checkoff Program was approved recently by the USDA to invest dollars efficiently into evolving technologies, and a project by the Department of Energy and University of Georgia revealed in January a successful sequencing of the sorghum genome – opening the door for further scientific breakthroughs.
As it turns out, despite its reputation for fast growth, sweet sorghum may become the biggest late bloomer of them all! Let’s just hope it doesn’t make the cost of sorghum syrup go up.