Life cycle assessment and techno-economic analysis of ethanol production via coal and its competitors: A comparative study

The world's first industrialized coal-based fuel ethanol (CBFE) and emerging second-generation fuel bioethanol (SGFB) routes are promising alternatives and potential competitors to the conventional first-generation fuel bioethanol (FGFB) route. Understanding the comprehensive competitiveness of the three fuel ethanol production routes is important for the development of clean and low-carbon transportation worldwide. However, there is currently a dearth of related knowledge and scientific data. In this study, we identified and compared the strengths and weaknesses of the three fuel ethanol production routes using an assessment framework that integrates life cycle assessment, techno-economic analysis, and entropy weight method. Environmental performance was investigated with the 18 midpoint impact categories of the ReCiPe 2016 method and modeled using the SimaPro software. Economic performance was represented using the net present value, dynamic payback period, and internal rate of return. The results demonstrated the highest comprehensive score in the SGFB route owing to its excellent environmental performance, which will likely address the unsustainability of the FGFB route through the efficient utilization of agricultural residuals. Owing to its considerable economic benefit, the industrialization of the CBFE route not only offers a new downstream chain in the coal industry but also diversifies the sources of fuel ethanol away from biomass. However, such a promising alternative faces a substantial challenge associated with its significant environmental impact, especially with its high greenhouse gas emissions. These results provide valuable information on the relative advantages and disadvantages of the CBFE, FGFB, and SGFB routes for scientific tradeoffs and decisions.