تحول در قاعده کلی اعزام و توزیع انرژی چین و سیاست جدید اعزام و توزیع ذخیره انرژی

With social economic reform in the past decades, the power industry of China is gradually evolving from a highly integrated one toward an electricity market, which can be characterized based on the transition of the power dispatch principle. To attract investment in the power generating industry, China introduced non-state-owned power plants to the original system of a highly vertically integrated power industry with annual power generation quota guarantees, which makes the traditional economic dispatch principle not applicable. The newly debuted energy saving power dispatch (ESPD) is an attempt to fully exploit the maximum energy savings and was implemented by an administrative code. Starting in August 2007, the pilot operation of the ESPD was implemented in five provinces, but after two years, it is still not widely applied all over the country. This paper details the transition of China’s power dispatch principle with particular attention to its origin and content. Moreover, the factors that influence the ESPD’s actual energy saving effect are discussed, as well as the sustainability of the policy.

Electricity is the most convenient form of energy consumed in the world. Therefore, primary energy, such as hydro energy, coal, oil, natural gas, or nuclear energy, is often converted into electricity by power plants and provided to end users by a transmission and distribution network. China’s generation capacity reached 874 GW at the end of 2009 (State Electricity Regulation Commission of China, 2010), and China is expected to become the largest power producing country in the world, with a capacity of 1186 GW in 2020 (International Energy Agency, 2007). The quickly developing economy drastically increases the demand for electricity, exerting great pressure on the Chinese government. Because the efficiency of energy consumption largely depends on both the type of primary energy and conversion technology, to save energy and reduce pollutant emission, renewable energy and high efficiency generation units need to be promoted to dispatch power. Generally speaking, the traditional vertically integrated power system is operated by strictly regulated monopolist-franchised companies or a sector of the government. Economic dispatch, which aims at gaining the greatest economy within the bounds of prescribed limitations, is the classic power dispatch principle and has been intensively studied in the past several decades (Luo et al., 1986 and Lin et al., 1987). The well-known equal incremental principle is developed and applied to allocate the load among all the generators by minimizing production cost, taking into account line losses. After the deregulation of the power industry, IPPs (independent power producers) were introduced, and their power dispatch is defined based on the outcome of market transactions and considering security constraints (Ongsakul and Chayakulkheeree, 2003 and Fernandes and Almeida, 2003). Market results in these industries will be fully respected, while the security of the system with regard to reactive power management, frequency control, AGC (automatic generation control), and others can be assured by purchasing ancillary service in the corresponding markets or can be provided setting compulsory obligations for the market players. Whether the power of one generator can be dispatched largely depends on its offering price, set to promote competition and increase efficiency. An obvious distinction between the power dispatch mechanism before and after deregulation is that it formerly operated to minimize the overall production cost for all of the generators with a predefined selling price. Since deregulation, it has functioned to dispatch power based on the voluntary prices and quantities determined by the various market participants, whose objective is to maximize their own profits, and the price is determined by the market. Therefore, higher efficiency generated energy was dispatched with a higher priority before deregulation, and it is also more competitive in the electricity market, where strategic bidding is allowed. However, neither before nor after deregulation has there been any economic advantage to using renewable resource-generated electricity, which is not economically competitive enough with current technology, and special measures are necessary to foster the development of renewable source electricity. The current situation in China is much more complicated with respect to the cases mentioned above. While it started in 1998, the transition of China’s power industry toward an electricity market is still under way. Great efforts have been devoted in the past 10 years to unbundle the vertically integrated power industry and introduce competition, but the actual time schedule for establishing a market mechanism remains unclear. Moreover, reform of the electricity industry is tightly related to the political situation. In the national campaign for saving energy and reducing pollutant emission, the power industry, which represents about two-thirds of the total coal consumption of the country, is expected to make a significant contribution. A strict energy saving power dispatch (ESPD) policy that determines the power dispatching order in terms of the efficiency and pollutant emission indices of the generating units was jointly issued by the National Development and Reform Commission (NDRC), the State Electricity Regulation Commission (SERC) and the Ministry of Environmental Protection (MEP) on August 27, 2007 (State Council of China, 2007a and State Council of China, 2007b). Apparently, this policy fits neither the market mechanism nor the traditional economic dispatch mode, and it lessens the prospect of the electricity market target defined in the 11th national five-year plan1 (Chang and Wang, 2010; State Council of China, 2007a). In this paper, we will examine the dispatch policy in China and analyze the background, content and impact of the ESPD policy in detail. The remainder of this paper is organized as follows: Section 2 introduces the traditional power dispatch principle that was in place in China before the deregulation of the power industry started; in Section 3, two power dispatch approaches that had once been temporarily applied or tried during the reform of the electricity sector are discussed; while the ESPD policy is thoroughly investigated with respect to motive, content and implementation in Section 4; numerical analysis is presented in Section 5; and finally, conclusions are drawn in Section 6.

As an economically rapidly booming country in the past several decades, China has already become the second largest energy consuming country, with a high increase rate of energy demand. The electricity sector consumes more than two-thirds of the coal production of the country and plays a very important role in the energy market. Starting in the 1980s, the power industry of China has been undergoing significant institutional changes toward marketization, which will greatly impact the operation of the power system. The purpose of this report was to gain insight into the evolution of the power industry institution by reviewing the changes associated with the power dispatch principle. The newly implemented ESPD policy, which is still waiting for widespread implementation, was carefully examined. Through this investigation, we found that the IPPs and investments other than state-owned capital were introduced in the early 1980s to attract power industry investment. Instead of the economic dispatch principle, the generation quota-based power dispatch was implemented to ensure payback to the investors. The objective of marketization of the power industry was set in the 1990s, and power dispatch based on bilateral contracts or market bidding was experimentally implemented in a number of pilot provincial or regional power systems on several occasions. In recent years, energy and environmental pressure pushed the authorities to allow GRT, i.e., generation quota trade to improve energy use efficiency by shifting the generation quota from the lower efficiency units to the higher efficiency ones. To fully exploit the potential of energy savings, in the end of 2007, the ESPD policy, which defines the power dispatch in terms of the efficiency of the units, was employed and operated in five pilot provinces. The implementation of the ESPD was a revolutionary change of the power dispatch principle because the generation quotas of the units are no longer guaranteed. The ESPD will facilitate the full use of renewable energy sources and high efficiency units. However, it is theoretically contradictory to the market mechanism, and it has remained in the pilot operation stage for the past two years due to technical and economic obstacles. From the theoretical analysis of this paper and numerical computation using the IEEE-118-bus system to compare the economic and physical effects of the ESPD and traditional power dispatch approach, we come to the following conclusions on the ESPD: (1) The ESPD defines only the technical aspects of the power dispatch for energy saving, and the economic sustainability problem with reference to the grid company and the issue of low efficiency but technically indispensable units need to be fully considered and settled. Otherwise, power system security and the sustainability of the policy will be negatively impacted. (2) The ESPD defines power dispatch according to physical indices. Therefore, it is not naturally compatible with the direction of power industry marketization. The transition from the ESPD to the market-based power dispatch deserves further attention. (3) The ESPD will increase the overall efficiency of the system and save energy, but the actual effects will be hugely impacted by power supply and provision rationing. China often suffers from power shortages, and this will impose negative impacts on the energy saving effects of the ESPD application because the ESPD is not applicable without sufficient power supply. (4) In the original version of the ESPD, transmission losses were not addressed, which should be fully considered to maximize the overall energy efficiency of power system operation. Additionally, transmission constraints must be carefully examined, and the transmission network needs to be reinforced to facilitate ESPD implementation because originally, the transmission infrastructure was built for the purpose of accommodating the traditional power dispatch approach.