关键词: 能值分析, 循环经济, 资源型城市, 榆林市

Abstract: Many resource-based cities are faced with more and more seriously resource exhaust，environment pollution and development dilemma in China. Circular economy is an important growth patterns for the resource-based cities to realize the transition of sustainable development，meanwhile，scientific evaluation on development level of circular economy is a foundation theory problem. Emergy theory coined by ODUM H T is a new method to research ecosystem and economic system of human society，analyze the true value of environmental resources and their relationships quantificationally.  Emergy is defined as the energy of one type required in transformation to generate a flow or storage.  Solar emergy of a flow or storage is the solar energy required to generate a flow or storage. Its unites are solar emergy joules （abbreviated sej）. Applying the emergy theory，some indices and ratios such as the environmental loading ratio（ELR），the net emergy yield ratio（NEYR）and emergy sustainable index（ESI）can be calculated. Based on emergy theory，taking the resource-based city Yulin in the Northern of Shaanxi Province as an example，from such five aspects as emergy flow，social & economy development，resource recycling utilization，resource & environment security and comprehensive index，this paper analyzed and evaluated the development condition and level of circular economy of Yulin from 2000 to 2010. Results showed as follows：the natural resources of Yulin City were abundant and the ratio of emergy self-supplying was above 99%，it belonged to resource out-putting type region. The high-speed economy development based the basis of a large consumption of nonrenewable resources，still carried on a kind of high resource consumption，extensive economic development mode； although the resource recycle ratio （RRR） increased year by year，but the emergy sustainable index （ESI），the sustainable development index （SDI），the emergy recycle economy index （EREI） and the urban eco-efficiency index （UEI） declined year by year. Based on the “three and one” mode of circulation economic，some measures should be taken to realize sustainable development of Yulin City in the future such as: Strengthen the input emergy’s introducing to promote the emergy flow rationally； Relying on technology innovation and technological transformation to improve the efficiency of input emergy use and waste recycling； Further exploiting renewable resources to promote regional industrial system ecological tendency.

Key words: emergy analysis, circular economy, resource-based city, Yulin City