Comparative Life Cycle Assessment of Bioethanol Production from Different Generations of Biomass and Waste Feedstocks

The emissions from transportation have been increasing rapidly in the last decade, accounting for second highest greenhouse gas emissions in energy sector. Replacing crude oil-based fuels with biofuels derived from bio-based feedstocks can significantly reduce the carbon footprint and environmental impact of transportation. In comparison to other forms of renewable energy, biofuels would require relatively less infrastructure investment. This study conducts a comprehensive analysis of the Life Cycle Inventory (LCI) and evaluates the environmental impact of producing bioethanol from various agricultural and waste feedstocks that are available globally. Procedures used for the collection of LCI data and the selection of Life Cycle Impact Assessment (LCIA) methods are outlined. The results from the global LCIA indicate that waste-based feedstocks have the least impact. Using second-generation feedstocks can enhance organic and municipal solid waste management while accounting for the food-versus-fuel challenge faced by the industry. It is shown that in comparison to agriculture-based feedstocks, organic solid waste feedstocks require less material consumption and land use for bioethanol production. By utilizing the most commonly available waste as feedstocks, this study provides a sustainable and global solution to reduce emissions in the transportation sector.