【作者】 耿江波；

【导师】 范英；

【作者基本信息】 中国科学技术大学 ， 管理科学与工程， 2014， 博士

【摘要】 天然气作为清洁的化石能源,对于保障国家能源供应安全及应对气候变化问题具有不可替代的战略意义。随着世界天然气贸易活动的日益活跃以及北美页岩气革命带来的新挑战,国际天然气市场特征正在变得更加复杂,面临许多新的不确定性,需要进一步深入的研究。同时,我国作为世界主要的天然气消费和进口大国,为了实现低碳经济转型,未来对天然气的需求和对进口的依赖也将越来越大,如何保障我国天然气供应安全也是亟待解决的问题。因此,在此大背景下,对国际天然气市场的价格波动特征、影响机理、贸易演化规律以及对我国天然气供应安全进行系统的深入分析,有利于进一步认识国际天然气市场复杂多变的市场特征,准确把握国际天然气市场规律和未来的发展趋势,为我国制定合理的天然气发展战略,保障我国天然气供应安全提供理论依据和决策支持。本文主要从世界三大区域市场天然气价格的波动特征、天然气价格的宏观影响因素、世界天然气贸易演化规律及中国液化天然气进口安全策略等四个方面,综合运用计量经济学、复杂网络、图论及运筹学等理论与方法,对国际天然气市场及中国液化天然气供应安全策略等展开深入的研究。本文的主要研究工作和结论如下：(1)结合集成经验模态分解和交叉相关性分析模型,从多时间尺度视角分析了世界三大区域市场天然气价格的波动特征以及不同频度下天然气价格波动的主要影响因素。研究结果表明,北美天然气价格受市场供需影响较大,影响幅度高达5美元甚至更高；同时受到飓风及页岩气革命等突发重大事件的影响也非常大,影响幅度超过2.5美元。而欧洲和日本天然气价格则主要由其价格的趋势项所决定。此外,国际原油价格高频及低频波动对北美天然气价格高频波动有一定的影响,但其趋势项对北美天然气价格的趋势项影响较有限；同时,北美地区天然气的库存量还不足以影响北美天然气市场的供需变化；然而日本与欧洲天然气进口价格主要受到国际原油价格趋势项的影响,且响应时间较短,一般分别为1-3个月及1-6个月。(2)综合运用面板协整及向量自回归模型,分析了世界经济活动与国际原油价格对世界三大区域市场天然气进口价格的影响,采用VAR、脉冲响应函数及方差分解方法分析了国际原油价格波动、上涨和下跌对世界三大区域市场天然气进口价格的冲击作用。研究结果表明,世界经济与国际原油价格对世界三大区域市场的天然气进口价格存在显著的长期的正向影响。世界经济活动对北美市场的影响相对较大,而亚洲和欧洲天然气进口价格则主要受国际油价的影响。主要是因为在北美天然气市场已经形成由市场供需来决定天然气价格的定价机制,而欧洲和亚洲天然气定价机制是基于国际原油价格的,特别是日本,其天然气价格完全参照国际原油价格。国际原油价格波动对三大区域市场天然气进口价格均存在负向的冲击作用,但各区域天然气价格响应程度有所差异。其中,油价波动对北美天然气进口价格冲击作用很弱；对欧洲天然气价格的冲击存在滞后效应；对亚洲天然气进口价格的负向影响最为显著,影响幅度大,持续时间较长。此外,三大区域市场天然气进口价格对油价上涨和下跌冲击呈现不对称响应机制,油价下跌的冲击作用相对更强一些。(3)构建了世界液化天然气与管道运输天然气贸易复杂网络,分析了世界天然气贸易格局的特征和动态演化规律；构建了国际天然气市场最小生成树模型,分析了国际天然气市场融合程度与天然气贸易之间的关系。研究结果表明,天然气贸易的区域分布和贸易形式具有很大的差异性,北美市场以管道运输天然气贸易为主,亚洲市场以LNG贸易为主,在欧洲市场两种贸易方式并重；LNG贸易网络与管道运输天然气贸易进出口网络均为无标度网络,网络中的国家存在异质性；LNG贸易网络相对管道运输天然气贸易网络联系更加紧密,LNG贸易呈现出口市场垄断程度加深及进口市场竞争更加激烈的态势；世界天然气市场仍然处于分离状态,还没有形成统一的市场,但是欧洲与亚洲市场的融合程度在加强。世界天然气市场结构演化与世界区域间LNG贸易的关系密切,世界天然气市场融合程度与区域间的LNG贸易量具有相互促进作用。(4)构建了液化天然气海运运输风险指数,在此基础上主要考虑液化天然气进口成本、液化天然气进口来源国国家政治风险以及液化天然气海运运输风险三个风险因素,构建了中国液化天然气进口安全多目标规划模型,对我国液化天然气供应安全进行了综合分析。研究结果表明,在不考虑极端事件情景时,与实际进口策略相比,最优进口策略中减少了天然气价格或者海运运输风险相对较高的埃及、赤道几内亚、尼日利亚、卡塔尔、阿联酋及也门等国的进口量,增加了从运输距离较近且价格较低的特立尼达和多巴哥、俄罗斯及马来西亚的进口量；在考虑当印度尼西亚发生极端突发事件或者当从印度尼西亚进口LNG时发生极端海运运输风险事件情景,中国LNG进口将转向国家政治风险较低的阿联酋。实证分析表明所构建的中国LNG进口安全多目标规划模型是有效的。更多还原

【Abstract】 Natural gas, as a kind of clean fossil energy, has irreplaceable strategic significance to protect national energy supply security and tackle climate change. With the increasingly activity of global natural gas trade and the new challenges that the shale gas revolution in North America has brought, the international natural gas market is becoming more complex and facing many new uncertainties, so the further in-depth research is need. Meanwhile, in order to achieve the low carbon economy, as the world’s leading natural gas consumer and importer, China’s future demand for natural gas and dependency on natural gas imports will also be growing, so how to protect China’s natural gas supply security has become a serious problem. Therefore, under this background, the in-depth and systemic analysis on the volatility characteristics of international natural gas prices, the mechanism of the impact on regional natural gas prices, the evolution of global natural gas trade and China’s natural gas supply security is conducive to understanding the complex and volatile characteristics of international natural gas market better, accurately grasping the market laws and future trends of the international natural gas market, and providing the theoretical basis and decision support for developing reasonable strategies of natural gas development and protecting China’s natural gas supply security.From four aspects:the volatility characteristics of natural gas prices for the world’s three regional markets, macroeconomic factors on regional natural gas prices, the evolution of global natural gas trade pattern and the safety strategies of China’s LNG import, this paper systematically used the theory and methods of econometrics, statistics, complex networks, graph theory, operational research and other disciplines, and proposed a series comprehensive models to study the international natural gas market and the strategies of China’s LNG supply security thoroughly. The main research and conclusions are as follows:(1) Combined Ensemble Empirical Mode Decomposition with cross-correlation analysis models, the volatility characteristics of natural gas prices in the world’s three regional markets and the main impact factors for natural gas price fluctuations at different frequencies are analyzed from the perspective of multiple time scales.The results show that the North American natural gas price was mainly influenced by the market supply and demand and the amount of fluctuation was as much as$5or higher; simultaneously it was affected by hurricanes, the shale gas revolution and other emergencies, the impact was also very large and the amount of fluctuation was more than$2.5. Natural gas prices in Europe and Japan were determined by the trends of natural gas prices, respectively. In addition, the high and low frequency fluctuations of the international crude oil prices have an impact on the high-frequency fluctuations of North American natural gas prices, but the impact that the trend term of international crude oil prices has on North American natural gas prices was limited; meanwhile, inventories of natural gas in North America was not enough to affect the changes of the supply and demand of North American natural gas markets; however, Japanese and European natural gas import prices were mainly affected by the trend term of international crude oil prices, the response time was shorter, and the time generally was1to3months and1to6months, respectively.(2) The panel cointegration model was used to analyze the impact of global economic activity and international crude oil prices on natural gas import prices in three major regional natural gas markets and further VAR, impulse response functions and variance decomposition analysis models were used to investigate the shock impacts of the volatility and the increase and decrease of crude oil prices on regional natural gas import prices.The results show that both global economic activity and international crude oil prices have significant long-term positive effects on natural gas import prices in the world’s three regional gas markets. Global economic activity has a significant impact on the natural gas import prices in the North American market, while natural gas import prices in Asia and Europe were mainly affected by international crude oil prices. This is because natural gas prices have been mainly affected by the supply and demand of natural gas in North America, while natural gas prices in Asia and Europe are almost always based on the oil-index, and especially for Japan, its natural gas import prices are absolutely based on international crude oil prices. The volatility of international crude oil prices has a negative impact on regional natural gas import prices and the impact is different for each of the regions. The shock impact is weak in North America, lags in Europe and is most significant in Asia. In addition, the response of natural gas import prices to increases and decreases in international crude oil prices shows an asymmetrical mechanism, of which the decrease impact is relatively stronger.(3) The complex networks of the global liquefied natural gas and pipeline natural gas trade were constructed, repectively; the characteristics and the dynamic evolution of the global natural gas trade patterns were analyzed; the minimum spanning tree models of the international natural gas market were constructed to analyze the relationship between the international natural gas market structure and inter-regional LNG trade.The results show that the great differences exist in the regional distribution and the natural gas trade forms. The natural gas trade is mainly by pipeline in the North American market, the LNG trade in Asian markets, and both of two trade forms in the European market. Both the LNG trade network and pipeline gas trade network have the characteristics of scale-free networks. This shows that national heterogeneity exists in the natural gas trade networks and that the impact that each country has on the overall trade network and the position that each country has in the overall trade network are different. The tightness of the LNG trade network is relatively higher than that of the pipeline gas trade network. The level of monopoly in the LNG export and import market is increasing. The natural gas markets in North America, Europe and Asia are not integrated into a unified global natural gas market. However, the degree of integration between the European and Asian markets is high. The evolution of the international gas market structure and the inter-regional LNG trade is closely related, and the improvement of the integration degree in the international natural gas market and the increase of inter-regional LNG trade have mutually reinforcing effects.(4) The marine transportation risk index of liquefied natural gas was constructed, and on this basis, the multi-objective programming model on China’s LNG imports was constructed to study China’s LNG supply security comprehensively, which mainly considered the LNG import cost, the exporting countries’political risk as well as the marine transportation risk of LNG imports.The results show that in situations that extreme events were not considered, comparing with the actual import strategy, the optimal strategy reduced the import volume from Egypt, Equatorial Guinea, Nigeria, Qatar, the United Arab Emirates and Yemen whose natural gas prices or maritime transport risks were relatively higher and increased the import volume from Trinidad and Tobago, Russia and Malaysia whose maritime transport risks or natural gas prices were relatively lower; in situations that extreme events for Indonesia’s maritime transport risk or national political risk, China’s LNG import will shift from Indonesia to UAE whose maritime transport risk or national political risk were relatively lower. The empirical analysis shows that the multi-objective programming model of China’s LNG supply security that this paper constructed was valid.更多还原