中文摘要：

西部地区是中国国家现代化发展的能源供应基地，其供应潜力主要通过煤炭外运来实现。在资源赋存和经济发展两者空间差异的共同作用下，西部地区成为国家煤炭外输的重要基地。数据分析表明，在西部地区煤炭的外输过程中，西北区的作用至关重要。其煤炭供应不仅量大、且范围广；同时，供应半径的定量分析发现，无论是在总体还是在省区级层次上，西部地区煤炭供应半径均呈现出先增后减的基本趋势，其拐点出现在20世纪90年代；进一步分析认为，上述煤炭供应半径的变化是西部地区自身城市化发展所导致的能源需求增大的一种必然结果。有鉴于此，西部地区煤炭供应的合理模式和其作为国家能源供应基地的可持续发展方向应引起更加深刻和广泛的反思。

英文摘要：

As the basic element of modernization, energy has become more and more important in the world today. Energy safety is closely related to a nation＇ s future. The western part of China is the energy supply base of the country, and coal accounts for more than 95 percents of the total primary energy supply of West China. Being rich in coal reserves, which have become a major resource for economic development, the western area becomes the energy source of coal supply in China, and northwestern region plays a more important role than the southwestern region. According to historical data, northwest China provided more coal to vaster regions than southwestern area, so it proves the major coal source. The provinces providing coal to other provinces usually give priority to their own demand before meeting that of the neighbors＇. While such priority is kept, the supplied scope is expanding, and no province can hold to the priority as before. The self-supply proportions of Inner Mongolia and Shaanxi have decreased a lot. For instance, from 1975 to 2005, Inner Mongolia experienced a drop of self-supply proportion from 99.8% to 19.2%, and the rate in Shaanxi slumped from 89.9% to 29.0%. Coal supply radiuses at both provincial and regional levels share the same changing trend of increase at first and decrease afterwords with the turning point in the 1990s. Such situation reflects that coal supply in the western area has changed from supplying outwards with surplus to only meeting its own need largely, although the total amount of coal supply is increasing. The influence of West China coal supply to other regions is becoming weaker. Further study shows that the reason for this change is increase in energy demand caused by the urbanization of West China itself. Coal shortage in Yunnan in 2008 exemplifies this situation. As one of the largest coal providers of China, Yunnan has faced serious coal shortage for electricity industry, and the gap was beyond 8 million tons. Yunnan is the second fastest in urbanization of western. C