Sweet Sorghum Ethanol Instead of Maize or Cane

Sweet sorghum requires half the water and fertilizer of corn, and uses less electricity. Compared to sugar cane, sorghum uses only 1/3 the amount of water, and grows in a wider range of climates.

The timing may be right for sweet sorghum. The United States is reaching its limits on using corn for ethanol, and global concerns are rising about using grains to make fuel while food prices soar. At the same time, researchers are looking for ways to make biofuels that would do more to reduce carbon dioxide emissions. Sweet sorghum gets good marks on all counts.

In India, where researchers have made ethanol from sweet sorghum recently, it’s known as a smart crop, because farmers can grow it for grain for food or for the stalks for animal feed or ethanol. It will grow in hot and dry conditions, and it tolerates salty land and waterlogging.

Sweet sorghum is harvested for its juice before the mature plant forms clusters of grain. The stalks are pressed, and the juice is fermented and distilled to make ethanol. The process is simpler and requires less electricity than making ethanol from corn.

Growing sweet sorghum requires only about half the water needed for corn and about half the nitrogen fertilizer. And unlike sugarcane, which grows best in tropical conditions, fast-growing sweet sorghum can be grown in much of the country during the summer. __Source

Sorghum is bulky, and requires local and regional processing and/or pre-processing. This encourages the growth of local industry, which is beneficial for small to medium sized communities.

"Its water requirement is one-third that of sugarcane, and its growing period is short enough to allow harvesting twice a year. While sugarcane is propagated from stem cuttings, sweet sorghum is sown with seed - just 4.5 kg is enough for a hectare of land, compared to 4,500-6,000 kg of sugarcane cuttings." Sweet sorghum's potential as an energy crop - it produces up to 7,000 litres of ethanol per hectare - makes it highly attractive for countries like China [and the US], which is expected to exhaust its economically recoverable petroleum reserves by 2016. __Source

Sugar cane is particular about its growing climate, and likes moist tropical areas the best. In the US, cane grows well in Hawaii, Florida, Louisiana, and parts of Texas. But sweet sorghum grows well across much of the traditional US farm belt, in a much wider growing region than cane. Given its advantages as an ethanol crop over both cane and corn, sweet sorghum should see more acreage soon.

Sorghum should be seen as a "bridge" crop. Currently, its sugar-producing properties are most valued in ethanol production. Eventually, the sheer biomass capacity of sorghum may become its most valued property.