Potential emissions of Kyoto and non-Kyoto climate active compounds in the production of sugarcane ethanol

Résumé 0

"Sugarcane ethanol is the most commercially developed liquidbiofuel. The potential emissions of Kyoto and non-Kyoto Protocolclimate active compounds in the production of sugarcane ethanolin agricultural lands are evaluated herein. Various scenariosare considered, such as low or high N2O emission from Nfertilizers,inclusion or not of pre-harvest burning, uncontrolledor controlled emissions in bagasse based boilers, and 20 or 100years time horizons in GWPs. The CO2 emitted in ethanol fuelcombustion is recycled during sugarcane “re-growing” and doesnot count as greenhouse gas. However, even though many uncertaintiesremain, the available information allows estimatingthat CO2-eq emissions are very large when ethanol production isbased on pre-harvest burning and there is non-controlled particleemission in boilers. In these scenarios, compared with the combustionof equivalent amounts of gasoline, higher CO2-eq emissionwould take place. Halting sugarcane field burning wouldnot be sufficient to revert the situation, especially in a 20-yearstime horizon. Only when more environmental friendly proceduresare applied, a significant saving of CO2-eq emissions occurs at20 and 100-years horizon scenarios. In all scenarios, non-KyotoProtocol compounds make an important net contribution. Therefore,if a real evaluation of climate active compounds emissionsis to be reached, it would be crucial to include these compoundsin life cycles studies. To reduce uncertainties, especially of non-Kyoto compounds, additional research is needed."