28th June, 2011
Dear all,
the by-product exploitation is the right way to achieve the sustainability of the sweet sorghum chain model. In another forum the topic was the vinasse exploitation. In this topic I would like to focus on the use of bagasse.
In order to start the discussion nothing is better than use an appropriate example from a sugarcane bioethanol chain, and so I report a recent article written by Seabra and Macedo, about a study in Brazil. Here you could find the abstract.

This work compares the technical, economic and environmental (GHG emissions mitigation) performance of power generation and ethanol production from sugarcane residual biomass, considering conversion plants adjacent to a sugarcane mill in Brazil. Systems performances were simulated for a projected enzymatic saccharification co-fermentation plant (Ethanol option) and for a commercial steam- Rankine power plant (Electricity option). Surplus bagasse from the mill would be used as fuel/raw material for conversion, while cane trash collected from the field would be used as supplementary fuel at the mill. For the Electricity option, the sugarcane biorefinery (mill+adjacent plant) would produce 91 L of ethanol per tonne of cane and export 130 kWh/t of cane, while for the Ethanol option the total ethanol production would be 124 L/t of cane with an electricity surplus of 50 kWh/t cane. The return on investment (ROI) related to the biochemical conversion route was 15.9%, compared with 23.2% for the power plant, for the conditions in Brazil. Considering the GHG emissions mitigation, the environmentally preferred option is the biochemical conversion route: the net avoided emissions associated to the adjacent plants are estimated to be 493 and 781 kg CO2eq/t of dry bagasse for the Electricity and Ethanol options, respectively.

Reference: J.E.A. Seabra, I.C. Macedo (2011). Comparative analysis for power generation and ethanol production from sugarcane residual biomass in Brazil. Energy Policy, 39, 421-428.

Corresponding author. E-mail address: [email protected] (J.E.Seabra).

The discussion is open…

Denis Picco