Environmental impact and energy balance assessment in ethanol production from sugarcane molasses: A life cycle analysis in southern India

Blending ethanol with fossil fuels is regarded as an important measure to reduce overall greenhouse gas emissions and the carbon footprint. However, there is a lack of comprehensive studies addressing overall greenhouse gas emissions and energy utilization during ethanol production from sugarcane in South India. This study represents a pioneering attempt to determine the emissions and resource utilization, enabling a comparison of the carbon footprint of the ethanol production process with that of using fossil fuels. The study employed the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model to calculate greenhouse gas emissions and resource utilization. Data was obtained from field studies conducted at Gayatri Sugars Limited, Telangana state, India. The collected data was input into a life cycle analysis (LCA) model in which two cane trash treatment methods were evaluated: burning and mulching. In terms of emissions, the CO2 emissions for one ton of sugarcane were 43.86 kg during cultivation, 45.98 kg during transportation, 69.05 kg during burning of cane trash, and 6.37 kg during the production of one ton of ethanol. The overall energy yield ratio was found to be 15.795 MJ/MJf. Emissions from sugarcane farming and transportation stages were high, significantly contributing to a high carbon footprint. The net emission was significantly lower for the mulching process, which also improved soil characteristics and fertility. The outcomes provide valuable insights for academia, industrial decision-makers, and policymakers at both state and central government levels.