中国天然气市场均衡价格分析——基于变分不等式转换的古诺模型研究

Equilibrium pricing of natural gas in China based on the cournot model of variational inequality transformation

资源定价改革是今后改革的重点突破领域。天然气作为一种重要的资源,其定价方式变革将推动中国天然气市场发展路径和走向,是整个天然气市场改革至关重要的一环。本文在经典的古诺模型基础上,通过变分不等式转换揭示了生产商、销售商与消费者这三个市场主体在天然气网络市场中的相互作用机制,并由此建立了天然气市场均衡模型;进而探讨了在成本异质性、多气源竞争以及政府限价三种不同情景下均衡价格与社会福利水平的变化;最后以上海市为例进行了实证分析。研究表明:1从社会福利最大化的角度看,中国天然气均衡价格受到上游竞争程度、管输成本、生产成本等因素的影响。推动上游企业降低成本并不能有利于全社会福利水平的改善,政府限价的长期均衡结果是导致需求的膨胀,进一步加剧了短缺;2定价方式的改革对于天然气均衡价格和均衡量影响程度不一。自由竞争的定价方式将驱离成本最高的气源。而中国当前采取的净回值定价改革发挥了需求函数的作用,有利于天然气产业链上下游的平稳发展;3天然气净回值法定价与市场自由竞争定价的效果相等,说明在目前天然气供需存在缺口、市场发育不完全的情况下,净回值法是一种有效的价格改革的过渡方式。过渡的条件是天然气管网的互联互通,形成区域节点价格。

Resource pricing reform will be an important breakthrough in future reform in China. As an important natural resource,natural gas pricing reform will promote the developmental path and direction for China＇s natural gas market and will be a critical step in the process of natural gas marketization. Here,we construct an equilibrium model for the natural gas network including natural gas producers,retailers and consumers and analyze interaction mechanisms among three market agents based on the classical Cournot model by means of variational inequality transformation. We applied a numerical equilibrium in order to discuss the change in equilibrium outcomes including equilibrium price and social welfare in three different cases such as cost heterogeneity,multi-gas competition and price regulation. We found that the equilibrium price of natural gas in China will be influenced by upstream competition,transportation costs and production costs in the format of social welfare. Reducing production costs for upstream sectors will not benefit the improvement of social welfare,whilst price regulation will reduce demand expansion in the long-run equilibrium and result in gas shortage. Different pricing reform has different effects on equilibrium price and quantity. Gas-to-gas pricing will drive away the higher cost gas producer. Net-back pricing should play its role through demand function and benefit the development of the natural gas value chain. In the environmental gap between production and demand,net-back pricing has the same effect as gas-to-gas competition pricing and is also an effective price reform transition regime. The condition of transition is the interconnection of gas pipelines which will help regional node pricing.