Abstract
In order to have a better understanding of the different aspects (economic performance, environmental impacts, sustainability) of the biogas projects, ecological–economic methods are used to formulate the integrated assessment framework. First, economic method (cost–benefit analysis) was used to assess the economic feasibility of the biogas project. Moreover, DEA method was used to make an economic efficiency assessment, based on which the optimization suggestions could be provided. In terms of the environmental impact evaluation, life-cycle assessment model was established to evaluate the energy cost and environmental impact of biogas system, based on which the key sections for energy saving and emission reduction of biogas systems could be identified. As for the sustainability analysis, considering ecological and social inputs, emergy analysis and exergy analysis were employed to quantify the environmental pressure, renewability, economic efficiency, and sustainability of biogas systems. Possible pathways to achieve sustainable and low-carbon biogas project management were also analyzed based on the scenario analysis. Finally, analytic hierarchy process (AHP) method was adopted to incorporate categories of indicators to have a comprehensive performance analysis of the biogas system.