Analysis of energy consumption in three systems for collecting sugarcane straw for use in power generation

Abstract

This work estimated the energy consumption of three straw-collection systems: baling, forager and whole-plant harvest system in which the chopped cane and straw are separated at the mill. About 12 t ha−1 yr−1 of straw can be collected for a typical sugarcane yield of 100 t ha−1 yr−1. The system with the lowest energy consumption was whole-plant harvesting, which used 2.0 L of diesel fuel per tonne of straw collected for a harvest area 30 km from the mill and when 75% of straw is collected. This value is approximately 40% lower than of the specific consumption estimated for the other systems and just 1–2% of the energy available from the straw. However, for successful application of the whole-plant harvest system, it is needed significant improvements to the efficiency of cane cleaning systems for straw separation. The thermal energy available from the straw when 75% is recovered is 182 GJ ha−1 yr−1, compared to 151 GJ ha−1 yr−1 of the ethanol that can be produced and approximately 174 GJ ha−1 yr−1 from the bagasse. If cane straw were used for electricity generation, an additional 12.6 MWh ha−1 yr−1 could be generated