Optimization and environmental and economic impact evaluation of the micro-energy network system on the basis of the load characteristics analysis

Abstract

Micro-energy networks have been widely used in power distribution systems. Previous studies have not addressed how to avoid these networks being dependent on the grid, due to the instability of distributed energy sources, or the lack of specific quantification of environmental and economic benefits. To understand the overall potential of the micro-energy network system for reducing environmental impacts, a life cycle assessment was conducted for the industrial park in Jinan. The analysis used a "cradle to gate" system boundary and a 1-year operation of the micro-energy network as the functional unit. The HOMER software was applied to build the research object's micro-energy network model and to carry out load analysis. The environmental impact and financial costs of the micro-energy network system have been estimated for different combinations of gas turbine units and water chilling units. The results show that all optimized scenarios could achieve an environmental impact reduction of more than 50% when compared to the initial scenario, regardless of the benefits of exporting surplus electricity. A reduction in environmental impacts as high as 71% could be achieved in optimized scenarios, although total costs would be 13% higher. The categories of freshwater ecotoxicity, marine ecotoxicity, human carcinogenic toxicity, and human noncarcinogenic toxicity were determined as the key impact categories. The impact of different electricity generation and the environmental benefits of exporting electricity are discussed. We concluded that micro-energy networks integrating natural gas and renewable energy technologies could bring about significant environmental benefits.