中国电力产业厂商市场力量的防范研究

【作者】 郭磊；

【导师】 殷醒民；

【作者基本信息】 复旦大学 ， 产业组织学， 2007， 博士

【摘要】 本文是一篇从产业组织理论的视角分析电力产业市场化改革问题的尝试之作。本文的主题是,在当前我国联营体模式的电力市场中,如何防范和抑制发电厂商的市场力量。本文通过实证分析,发现了我国电力市场中存在发电厂商施用市场力量的迹象。本文对于防范发电厂商市场力量的建议是,在供给侧实施差别价格拍卖并在需求侧实施可中断负荷服务。电力产业曾被认为是一个典型的自然垄断产业,维持了一百余年的发电、输电、配电和售电一体化的模式。上世纪九十年代以来,以英国为发端,出现了一个世界性的电力产业拆分与重组的浪潮,我国也于2002年末实现了“厂网分开”。然而电力市场并非是自发演进形成的,而是一个人工设计的市场,其运营规则和竞价机制难免存在这样或那样的纰漏。面对市场的疏漏、受到利益的驱使,从原一体化结构中剥离出来的独立的发电厂商,一定会最大限度地掘取潜在的利润。电力产业市场化的历程表明,各国的电力市场几乎都遇到了由发电厂商的市场力量所引发的电价波动的困扰。市场力量的行使不仅损害消费者的利益,同时还将危害电力市场的正常运行与健康发展,美国加州的电力危机就是一个很好的例证。由于新组建的电力市场特别容易受到市场力量的袭扰,一些西方学者将其列为电力市场的头号治理对象。我国经济学界对电力市场的研究到目前仍处于起步阶段,已有的分析都未能很好地结合电力产业的特性。作为一篇尝试之作,本文首先分析了电力产业的一些独有技术特征,如负荷具有不确定性、电力传输会受到线路容量的限制、存在短期的供给约束等。基于对这些技术特征的理解,通过理论借鉴与本文的实证,笔者发现不同于传统的产业组织理论中市场力量的观念,电力市场中的发电厂商并非自始至终地都在行使市场力量来抬高电价,它们行使市场力量需要一个适合的供需环境。凭借市场力量抬高电价的手法主要有两类:一是向联营体直接申报高价,二是采取容量囤积的策略。而无论发电厂商采取何种策略,都将造成电价的巨幅波动,这是发电厂商获取超额利润的载体。本文的实证分析表明,与其它一些初级电力市场类似,我国的试点市场中也存在发电厂商申报高价和囤积容量的现象。由于电价的巨幅波动是超额利润的载体,同时趸售市场规则的纰漏有可能导致市场力量的滥用,因此,笔者将分析的重点集中于市场规则、需求弹性和市场结构等三个方面。实际上本文抑制市场力量的出发点,就是在市场设计中尽量减少可能导致价格巨幅波动的那些因素。已有的拍卖研究成果显示,在不同的拍卖方式下价格的波动幅度是不相同的。受此启发,笔者在第五章通过对两种拍卖方式下供给函数的推导与对比分析,发现差别价格拍卖的供给曲线具有较高的价格弹性,因而笔者认为,在供给侧将目前的统一价格拍卖转换为差别价格拍卖将有助于抑制发电厂商的市场力量。电力需求的价格弹性过低,是发电厂商拥有市场力量的一个重要方面。一旦在需求侧建立起响应定价,发电侧的价格尖峰就可以及时地传递给消费者,这将使用户的需求得到抑制,从而削弱发电厂商行使市场力量的激励。但由于需求侧响应定价的实施首先应当有一个完善的峰谷电价体系平台,而目前我国的零售电价体系与一个科学的电价制度还相差甚远,同时还面临一个激励两难,因此应当考虑其它的方式来增加需求曲线的弹性。本文证明,在需求侧实施可中断负荷服务,可以增加需求曲线的价格弹性,起到与需求侧实时电价同样的抑制发电厂商市场力量的效果。而可中断负荷服务又避免了上面提到的缺陷,因而是一个非常理想的替代方案。本文在对电力市场的空间把握与市场集中度的度量方面,以及在对发电厂商的容量囤积策略的实证等方面具有创新性的贡献。本文的不足之处在于数理模型和计量工具的运用还不够深入。此外,由于各公司对数据的封锁,没有获得一些更加核心的信息。电力市场是一个新生事物,直至目前世界各国仍处于探索和完善的阶段。就当前我国的具体国情来分析,对联营体中市场力量的防范除了供给侧和需求侧两方面的措施外,还需要多种措施的配合,如继续拆分发电厂商、在长期中扩充发电装机容量与输电能力,以及行之有效的规制等。更多还原

【Abstract】 This dissertation tries to discuss some of the main issues of the power market-oriented reform in a framework of the industrial organization theory. The main objective of this dissertation is to find how to mitigate market power in the electricity power pool in our country. Through an empirical study we find some evidences of exercising market power by some of the generators in China. This dissertation gives some advices on preventing market power, including discriminatory price auction on supply side and interruptible services on demand side.Traditionally, the electric power industry has been regarded as a natural monopoly with generation, transmission and distribution integrated vertically well for 100 years. Since 1990, beginning in the U.K., there is a worldwide trend of restructuring in the electric power industry. China also unbundled its generation sector from the grid in 2002. However, the power market is not a direct result of independent actions by generators, distributors and customers, but an artificial market of a deliberate government policy. For this reason, oversights are hard to avoid in the market rules governing the operation. Prompted by profits, the independent producers separated from the vertically structure will attempt to exploit any profitable opportunities presented by the market rules. The course of the power market-oriented reform shows that high prices caused by the market power of the producers emerged in almost all areas after the supply side separated from the network. The Californian electricity crisis provides a stark evidence that market power will jeopardize the interest of the customers and impair power markets. Susceptible to the exercise of market power in the new power markets, mitigating them is therefore high on the agenda for regulators by some western scholars’ consideration.In our economics academic circles, power market is pending for further research. Many literatures can hardly discuss market power in the light of specific technologies. This dissertation tries to combine some characteristic such as system load indetermination, transmission capacity limitation and short-run generation constraints into the analyses. Based on the technique analysis and an empirical study, we find that generators in a power market are not exercising their market power all the time, as is different from the classic IO theory. When conditions exogenous to the behavior of the generators favor it, they will abuse their potential market power.Generators have two strategic weapons to exercise their market power: (1) the price bid for each generation set and (2) the capacity for each generation set made available to supply the market. Our empirical study shows that bidding and withholding strategy both can be found in our pilot power market, as is similar to the foreign markets.Market rules, market structure, and elasticity of demand are the important features of the power Pool which contribute to the ability of generators to abuse market power, so we focus on these factors in our analyses. In fact, the starting point of this dissertation is to minimize those market rules that can bring out wholesale price spikes.Auction studies suggest that price volatilities are differences between the uniform price auction and discriminatory price auction. Following their suggestion, we compare two supply functions using a uniform price and a discriminatory price auction for an electricity market, and find that the supply curves will typically be more price elastic using a DPA than UPA. Therefore, DPA is a better form for a power market to control the market power.Another source of generators’ market power is the low elasticity of the demand side. Responsive pricing can dampen the incentive of excising market power because price spikes in the wholesale market can curb the customs’ demand in time. However, responsive pricing needs a basis of complete peak-load pricing system. In our country, there is a long way for a reasonable retail price system to be achieved, and there is a incentive dilemma of the responsive pricing, so we should considering some other way to enhance the demand side elasticity. This dissertation shows that interruptible load service has the same effect as responsive pricing in building an elastic demand side and mitigating market power. However, interruptible load service avoids those shortcomings mentioned above, so it is an ideal scheme.This dissertation brings some original ideas on defining the range and measuring the concentration of the power market, and creates a new approach to study empirically of the capacity withholding strategy. There are some inadequacies in our analysis such as a plain model and simple econometric methods. Furthermore, we can’t get some core data because of the hard blockade of the information in the electric power industry in our country.Power market is still in its initial stage, and the market rules and structures still need to be investigated and improved. According to our national conditions, we should adopt various measures to prevent market power including newly installed capacity investments, transmission expansion and an effective regulation, besides methods mentioned above.更多还原