Comprehensive Benefits Evaluation And Analysis Of A Natural Gas Distributed Energy Project In Changsha

Since the research and application of distributed energy system starts late in China, the development of the distributed energy system is still faced with many problems recently, like challenges of concepts and cognitions, requirement of improvement in unit technologies and system integration technique. In addition, there still lacks a unanimously approved evaluation index system and a highly applicable evaluation model for the comprehensive benefit evaluation, because of the limited cognition caused by problems such as lack of integrated and systematic consideration, one-sided focus on a particular aspect and individually considering each benefit. In this paper, an applicable evaluation index system and evaluation model was established for comprehensive benefit evaluation of a natural gas distributed energy project in Changsha.Firstly, based on some mature comprehensive benefit evaluation results in other fields, the comprehensive benefits of natural gas distributed energy projects were divided into four aspects, namely economic benefits, energy conservation benefits, environmental benefits and social benefits. Each aspect was analyzed, and an evaluation index system of comprehensive benefits, which consists of four secondary evaluation indexes and fourteen tertiary evaluation indexes, was finally obtained. In the analysis of economic benefits, the impact factors of economic benefits of the distributed energy system were mainly analyzed, while the evaluation of economic benefits was not discussed too much since the evaluation system of economic benefits is relatively mature in China; in the analysis of energy efficiency benefits, the problem of comparing with energy efficiency of distributed energy system was resolved, the index of energy efficiency capacity per million yuan investment was introduced, beside with annual energy saving and overall energy utilization degree; in the analysis of environmental benefits, a negative evaluation-noise pollution was proposed, in order to avoid one-sided focus on emission reduction; in the analysis of social benefits, five social benefits about promoting distributed energy were presented according to the characteristics of distributed energy projects.Secondly, the evaluation model of comprehensive benefits, in which fuzzy analytic hierarchy process act as the core, was established based on related evaluation theories, and evaluation process was presented. The weight of each index was determined by analytic hierarchy process, the evaluation method is fuzzy synthetic evaluation method, and the values of qualitative indexes were determined by fuzzy statistical method, while the values of quantitative indexes were determined by membership function method.Lastly, a case analysis of a natural gas distributed energy station in Changsha was conducted with the established evaluation index system and evaluation model, the results show that the project is of good comprehensive benefits with bad economic benefits, good energy conservation benefits, environmental benefits and social benefits. The results are in accordance with the comments given by Expert Commenting, which indicates that the established model highly fits with this project. This research can provide reference for the comprehensive benefit evaluation of natural gas distributed energy projects of other styles and in other areas, and provide theoretical support for the promotion of natural gas distributed energy.