Electricity Production from Sugarcane Straw Recovered Through Bale System: Assessment of Retrofit Projects

Sugarcane straw has become available in large quantities in the field due to transition from manual to mechanical harvesting. Straw can be used as fuel for cogeneration systems of sugarcane mills to increase surplus electricity for commercialization. However, the exploitation of straw potential is still limited due to some challenges related to its agricultural recovery and industrial processing. The retrofit (additional installation) of existing sugarcane mills to process straw is an alternative to reduce investment and to allow a gradual utilization of this biomass. In this work, techno-economic and environmental assessment of straw recovery through bale system to increase electricity export was assessed. Two scenarios with straw recovery and processing were defined to take advantage of an existing cogeneration system, considering its operation in the season and off-season periods. An increase of up to 57% on surplus electricity was achieved. Both scenarios resulted in economically feasible alternatives. However, results were very sensitive to the variations on electricity prices and straw costs. In terms of environmental benefits, the bioelectricity presented a great potential to mitigate greenhouse gas emissions compared with natural gas–based electricity. The higher electricity surplus also affects the carbon intensity of ethanol, which can lead to indirect gains when the Brazilian program for biofuels incentive is implemented.