Are biofuels renewable energy sources?

Oct 2007

The objective of this study is to discuss biofuels renewability in a quantitative point of view. A comprehensive review of the energy balance literature and emergy assessment of biofuels production were carried out at the Laboratory of Ecological Engineering of the Food Engineering School at UNICAMP in order discuss these issues. From these perspective is possible to realize that biofuels use a high amount of fossil fuel energy in the agricultural and industrial conversion stages. When using Emergy Methodology the results showed that only 25% of the resources used to produce biofuel from soybean are renewable. Ethanol production from corn uses only 9% of renewable resources and when it is produced from sugarcane the renewable increase to 30% in conventional systems. Results show that small scale biofuels production using agroecological concepts present much better renewability (70%). Emergy accounting method showed quantitatively that biofuels are not renewable energy sources. If the biofuel production systems are not carefully designed as diversified small scale integrated systems, using the “eco-unit” perspective, the intensive exploration of land and fossil fuel use for biofuels production is more likely to result in green deserts and social damages than to become a renewable energy source to society.

By: E. Ortega; O. Cavalett; C. Pereira; F. Agostinho, J. Storfer

download this document:   546 kb