Sweet Sorghum: A Smart Biofuel Crop

s: Biofuel Crop, Smart Biofuel crop, Sweet Sorghum Philippines. Sweet Sorghum

In these days of soaring food prices worldwide, imagine a crop that provides food, livestock feed and biofuel. It grows in dry conditions, tolerates heat, salt and waterlogging and provides steady income for poor farmers. Sweet sorghum, a plant that grows to a height of 8 to 12 feet and looks like corn but with the grain on top rather than on the side of the plant, has all these qualities.

“Sweet sorghum provides an opportunity for developing countries to re-direct oil money that used to go overseas back into their own rural economies,” says Dr. William Dar, director general of the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), one of 15 allied centers supported by the Consultative Group on International Agricultural Research (CGIAR).

“We consider sweet sorghum an ideal ‘smart crop’ because it produces food as well as fuel,” Dr. Dar adds. “With proper management, smallholder farmers can improve their incomes by 20 percent compared to alternative crops in dry areas in India.”

In partnership with Rusni Distilleries and 791 farmers in Andhra Pradesh, India, ICRISAT helped to build and operate the world’s first commercial bioethanol plant, which began operations in June 2007. Locally produced sweet sorghum is used as feedstock.

The process is simple. To produce ethanol, the sorghum stalks are crushed, yielding sweet juice that is fermented and distilled to obtain bioethanol, a clean burning fuel with a high octane rating.

The grain can be used for food, chicken or cattle feed. Yet if it has been damaged by disease, no problem – it can also be used to make bioethanol, protecting farm incomes that would otherwise be lost.

The crushed stalks, called bagasse, can be burned to provide energy for the distillery. However, research by ICRISAT’s sister center, the International Livestock Research Institute (ILRI), has found that the bagasse value can be doubled if it is compacted in nutritious blocks and fed to cattle.

Similar public-private-farmer partnership projects with ICRISAT, local industries and farmers are also underway in the Philippines, Mexico, Mozambique and Kenya, as countries search for alternative fuels.

India intends to use a 10-percent ethanol blend to save an estimated 80 million liters (21 million gallons) of gasoline each year to ease the country’s growing need for gasoline and to reduce carbon emissions.

Advantages

Sweet sorghum in India costs $1.74 to produce a gallon of ethanol, compared with $2.19 for sugarcane and $2.12 for corn.

It has high positive energy balance, producing about eight units of energy for every unit of energy invested in its cultivation and production, roughly equivalent to sugarcane but four times more than for corn. Only 0.8 unit of energy is produced in fossil fuel production for every unit invested.

In the United States, the diversion of corn to bioethanol uses has contributed to increasing food prices. Since food-quality grain of sweet sorghum is not used in ethanol production, and is not in high demand in the global food market, it has little impact on food prices and food security.

Sweet sorghum hybrids have almost equal yields of grain as from grain sorghum hybrids and significantly higher stalk yields, so “food production would not be forfeited by switching from regular sorghum to sweet sorghum,” says ICRISAT sorghum breeder Dr. Belum Reddy. Improved sweet sorghum technology could even raise sorghum grain production significantly.

It is also easier and cheaper to grow sweet sorghum than other biofuel crops in India. Sweet sorghum grows on “free” rainwater, whereas sugarcane requires costly irrigation. Sweet sorghum is also more water-efficient: sugarcane consumes two and a half units of water to produce one unit of ethanol, whereas sweet sorghum produces one unit of ethanol from one unit of water.

Some recent reports have raised concerns that the cultivation of certain biofuel crops produces more greenhouse gases than is being saved. This is less likely to be the case for sweet sorghum, although research is needed to assess this carefully. Sweet sorghum is grown on already-farmed drylands that are low in carbon storage capacity, so the issue of clearing rainforest, of great concern for oil palm and sugarcane, does not apply.

Sweet sorghum will not replace sugarcane in parts of the developing world where those crops are well established, emphasizes Dr. Reddy. However, the need for irrigation and high rainfall makes it difficult to expand sugarcane production without moving into ecologically sensitive areas like rainforests.

Sunday, May 11 2008 (http://www.philstar.com)