Techno-economic and environmental assessment of bioenergy and livestock integrated systems in Brazil

Abstract

Bioenergy-livestock integrated systems (BLI) are a promising land-based option to meet future agricultural demands, while also alleviating pressure on land use and mitigating greenhouse gas (GHG) emission. However, their techno-economic feasibility and environmental implications are still unclear. This study performs a life cycle assessment and techno-economic assessment of key BLI systems in Brazil from a land management perspective. We considered pasture intensification options and use of biofuels by-products as animal feed supplement to release pasture area for additional crop production. BLI presents higher techno-economic feasibility compared to conventional systems, reducing payback time by almost half, and resulting in a five-fold increased net present value to initial investment ratio. The potential to avoid GHG emissions per hectare (replacing fossil fuels) is about two times higher in BLI than conventional system, mostly due to the possibility of producing more outputs using less area. Sugarcane ethanol produced under BLI scenarios outperformed conventional systems in eight out of nine addressed Sustainable Development Goals (SDGs), mainly because of the use of manure on sugarcane fields and use of bagasse as animal feed. Crops production to feed cattle in feedlots can increase acidification and eutrophication impacts, negatively influencing the meat production scores on SDG 2: Zero Hunger, 6: Clean Water and Sanitation, and 14: Life Below Water, for example. Conversely, meat produced in feedlots resulted in lower impacts on air quality and increased GHG mitigation, mostly due to shorter cycle duration, with better scores in SDG 11: Sustainable Cities and Communities and 13: Climate Action. These results might help to guide an enhanced integration of biofuels and livestock sectors in Brazil. BLI systems are expected to contribute to the achievement of climate mitigation targets while also reaching many of the SDGs and remaining techno-economically feasible.