Sugarcane as an energy source

Sugarcane is being used for centuries as a feedstock for sugar production, and all breeding programs around the world are producing new varieties with the objective to improve the sucrose yield per hectare, among other properties. In Brazil, ethanol became a significant coproduct of sugar mills more than a century ago and the first mandate to blend ethanol in the gasoline dates back to 1931. Toward the end of the of twentieth century, many countries, including Brazil, Mauritius and Reunion Islands, Guatemala, and India, started to generate significant amounts of surplus electricity, and this practice is becoming a trend for new sugar/ethanol mills. With this changing picture of the sugarcane industry, some specialists in the sector started to look at sugarcane as an energy feedstock rather than a food feedstock in such a way that other characteristics related to total primary energy content became important quality parameters. The second point is how efficiently this primary energy is converted to useful energy products (ethanol and surplus electricity). Now, from the energy viewpoint, not only the sucrose but also the fibers in the cane are important quality parameters. Taking the Brazilian average conditions, the primary energy content of sugarcane is around 7,400 MJ/tonne of cane or 510 GJ/ha/year, and in an average distillery, less than 30 % of it is converted into useful energy products. This work analyzes the present situation of the Brazilian sugarcane industry focused on the production of energy products and evaluates areas for improvements and new cane breeding goals for an energy-minded industry. The impacts of these improvements in the primary energy conversion efficiency will be estimated, and the barriers for maximum recovery will be pointed out.