SUGAR cane grown in Brazil and palm oil from Malaysia and Indonesia rank as the most sustainable of the current generation of biofuel crops, according to researchers at Wageningen University in the Netherlands.
Researchers at the university’s plant-science department compared nine crops on criteria including soil erosion, water use for each unit of energy produced and nitrogen usage, according to Sander de Vries, author of the comparative study.
“In terms of net energy, sugar cane has the best score of all energy crops,” Wageningen University’s De Vries said by telephone yesterday. “A crop like corn, which scores poorly, is at 10 percent of that.”
Biofuels production amounted to 83 billion liters (21.9 billion U.S. gallons) in 2008, up fourfold from 2000, and accounted for 1.5 percent of global transport fuel consumption, according to the International Energy Agency. First-generation biofuels have faced “heavy criticism” regarding their long- term effect on the environment, according to the IEA.
Sorghum in China, as well as oil palms and sugar cane, make the most efficient use of land, water, nitrogen and pesticides to produce a unit of energy, according to the study in the journal Biomass and Bioenergy. Provided no forest is cleared to grow the three crops, they produce “much less” greenhouse gases than fossil fuels, the study said.
“It takes a lot of water to grow sugar cane, but on balance you get a big return,” De Vries said. “You get back a lot of sugar cane.”
The crops were compared by ranking them against the best- performing plant on each of nine criteria, De Vries said. Sugar beet and rapeseed in Europe, cassava in Thailand and soybeans in Brazil had an average ranking, according to the study.
“In every case we looked at the dominant production area,” De Vries said. “With regards to erosion, oil palm scores well, rapeseed also. Soy doesn’t do well in terms of net energy, but does in nitrogen efficiency.”
Oil palm was most sustainable with regards to the maintenance of soil quality, according to the study, which disregarded effects on societies, economies and biodiversity.
U.S. corn and wheat in Europe, used to produce ethanol, had the worst sustainability score of the nine crops studied.
“It takes a lot of energy to process those crops,” De Vries said. “For corn it’s just positive. For wheat the balance of greenhouse-gas reductions is zero.”
Source : Business Times