Comparison of life-cycle energy consumption, carbon emissions and economic costs of coal to ethanol and bioethanol

The recently industrialized process of converting coal to ethanol (CTE) is a potential competitor of the conventional biomass to ethanol (BTE) conversion route. In this study, a life cycle analysis was employed to assess the energy consumption, carbon emissions and economic costs associated with CTE compared with those associated with BTE. The operation data for the world's first industrialized CTE project were incorporated into the analysis. It is estimated that energy consumption and carbon emissions are mostly from the ethanol production process. The capital investment input is largely in the form of equipment costs, and the production cost is mainly spent on purchasing feedstock and energy. Compared with BTE, CTE offers a feasible alternative for energy engineering applications, benefiting from a robust energy conservation effect and excellent economic competitiveness even with feedstock price fluctuations. However, such a promising route faces the challenge of high carbon emissions, which needs to be solved promptly. An effective way to address this issue is to improve the conversion efficiency according to sensitivity analysis. The results of this study demonstrate the energy engineering application value of CTE technology, provide important indicators for its improvement and help policymakers and the market to select the appropriate ethanol production route according to local resource conditions.