Brazilian, Chinese, and Pakistani researchers argue that the technology offers excellent prospects for being adopted in China

The second-generation ethanol produced from sugarcane bagasse has excellent potential for large-scale use in China, the second largest economy in the world, according to a review published in the scientific journal Renewable & Sustainable Energy Reviews. The authors – Chinese, Brazilian, and Pakistani researchers – stated that, as a large sugarcane producer, mainly to meet its internal demand for sugar, China could use the residue of that particular crop in the biofuels sector, as a means of contributing to its energy security and sustainable development.

“This crucial aspect of growing sugar cane in China has not yet been extensively exploited,” so write the authors, who present a critical analysis, a theoretical assessment regarding the subject, and comparisons with other types of raw materials. The Brazilian biofuels production model, from sugarcane, is used as an example in the article. “It is important to make the Brazilian experience known,” says chemical engineer Suani Teixeira Coelho, Professor in the Institute of Energy and the Environment (IEE) of the University of São Paulo (USP) and a researcher with the FAPESP Shell Research Centre for Gas Innovation (RCGI), who is one of the co-authors of the article. “Many of the issues that they might have, we have already resolved, because we have 40 years of experience. This article was a collaborative effort among developing countries.” Besides Professor Suani Coelho, the article is also authored by Doctoral candidate and RCGI researcher Danilo Perecin, who is currently visiting the Imperial College London, in the United Kingdom.

According to the authors, the bioethanol now produced in China is based mainly on corn, as a first-generation product. “The core purpose of that strategy was to balance the enormous domestic stockpiles of corn, maintain the price of the grain, and to stabilize the income of farmers,” they wrote. But the price of the grain for consumers rose and, in keeping with the principle that economic growth must not threaten food safety, the authorities suspended promoting this type of bioethanol.

The researchers stress that, although sugarcane is one of the most promising raw materials for producing first-generation bioethanol, it is complicated to replicate the Brazilian model in China for two main reasons.

The first is the high cost of producing sugarcane in China, due to the low level of mechanization in the field, the limited available land area adequate for planting, and the excessive use of chemical fertilizers. Therefore, the researchers write that the cost of producing sugarcane is nearly five times higher than in Brazil. Although Chinese productivity per hectare is slightly greater, the Asian nation has planted sugarcane on land area that is one-seventh the land used in Brazil.

Furthermore, China is the world’s third largest consumer of sugar and 90% of the production is obtained from sugarcane, while only 10% comes from sugar beets. Nevertheless, the nation’s production has been unable to meet all of the internal demand for sugar for the last 10 years. For that reason, China imports from three to four million tons of sugar per year – different from Brazil, which exports sugar and can use sugarcane plantations for other purposes.

On the other hand, the sugarcane crops yield the highest production per area, in terms of residues with lignocellulosic content, such as bagasse and straw, which are adequate for being used as a raw material for obtaining biofuel. Compared with the main food crops, sugarcane produces about three times more of this type of residue.

“Since some 110 million tons of sugarcane are produced every year in China, nearly 33 million tons of bagasse could be available. Therefore, theoretically speaking, about 6.5 million tons of ethanol can be produced from the bagasse, annually,” the article says.

Another characteristic of Chinese sugarcane production is its concentration mainly in the provinces of Guangxi, Yunnan, and Guangdong, in the south of the country, which provides a significant advantage, in terms of distribution of the biomass, since there are no additional costs for transporting it over long distances – different from other food crops that generate residues, like wheat, rice, and corn, whose plantations are spread throughout numerous regions of China.

According to the study, the main challenge for producing second-generation ethanol is the development of efficient means of converting sugarcane bagasse into cellulosic ethanol via large-scale industrial production methods. Therefore, the researchers suggest that, besides seeking to reduce the production costs of sugarcane in China, it would be necessary to improve the varieties of the plant through both traditional and more technological means, like the development of transgenics. They also point out the importance of government policies that support the market.

The abstract of the article “Sugarcane for bioethanol production: Potential of bagasse in Chinese perspective”, which is exclusively for magazine subscribers, can be read here.