Ethanol in Brazil: a review of its potential impact on the energy transition

Abstract Brazil is a global leader in ethanol production from sugarcane, with corn-based ethanol emerging as a significant alternative. Understanding the technical potential of ethanol production is essential for supporting decarbonization in the energy transition. Therefore, the current study aims to comprehensively review sustainable ethanol production in Brazil, focusing on sugarcane processing and the emerging role of corn-based ethanol. The review includes a brief overview of ethanol production, details on first-generation and second-generation ethanol production, mapping of sugarcane production and biorefineries, an analysis of ethanol carbon intensity (CI), conversion factors for second-generation ethanol production, co-products, bioenergy with carbon capture and storage (BECCS), and finally, an estimate of the ethanol production perspective along with the potential reduction of greenhouse gas emissions. The review indicates that co-products are important, and sustainable ethanol production can be increased by converting degraded pasturelands into agricultural crops or by utilizing second-crop corn in tropical climates. Results show that up to 351.6 M m 3 of sugarcane-based ethanol, equivalent to 7.51 EJ or 3.36 M barrels per day of crude oil, can be produced using 28 M ha when both 1G and 2G ethanol production are considered, while 98 M m 3 of corn-based ethanol can be produced using corn as a rotational crop, with full allocation for ethanol production. Additionally, implementing BECCS during the fermentation process could lead to cumulative net-negative emissions of 136.6 M tonnes of CO 2 , considered as carbon dioxide removal, when assuming an ethanol CI of 15.0 g CO 2-eq /MJ. Finally, an additional reduction of 526 M tonnes of CO 2 per year can be achieved due to the displacement of fossil fuels by ethanol.