Research On Long-term And Mid-term Generation Capacity Adequacy In Electricity Market Environment

The power industry restructuring all over the world has changed the mode of management, planning, and operation of the power industry. Accordingly, the mid-term and long-term generation capacity adequacy (GCA) problems gain new characteristics, facing new challenges. In the traditional environment, the long-term GCA is mainly on the accuracy of long-term load forecasting. However, in the new market environment, it turns to be the result of decentralized individual decision-making of generation companies (GENCOs). The shortage, redundancy or periodical variation of generation capacity in some countries have led to huge negative influence and attracted more and more attention. To ensure the long-term GCA is one of the most important and fundamental issues in designing and developing an electricity market. Several methods are proposed or employed in academic and industry fields, but none of them has been broadly approved. Some issues are required to be analyzed further, including whether the energy-only market could induce sufficient generation investment, which to be the most effective way in the practice, how to design new mechanisms and determine the pertinent parameters, who to be responsible for the GCA, which to be better between the market way and the regulation way, what to be the responsibilities of the government and so on. Meantime, the unit maintenance scheduling (UMS) which affects the mid-term GAC has been transformed from the centralized dispatch by the Indepent System Operator (ISO) to the decision-making of each individual GENCO for maximizing its own profit. To develop the framework of UMS in accordance to the requirement of the power market is the key to ensure the mid-term GCA. In this thesis, the above issues are investigated systematically and some significant results are obtained as detailed below.1. Based on the theoretical model and practical discussion, the paper makes analysis on the issue whether the energy-only market can ensure the long-term GCA. Both the theoretical deduction results under perfect condition and the discussion conclusions on actual performance under real environment show that it is difficult for the energy-only market to ensure generation capacity adequacy.2. Several widely employed or established methods are investigated, including similar traditional planning, capacity payments, capacity obligations, installed capacity market, locational installed capacity market, options, operating reserve payments, and capacity subscription. And the theoretical advantages and disadvantages, as well as the practical feasibility and the adaptive scope of these approaches are identified.3. The issues, such as entities responsible for the GCA and the design way, are specified; and the characteristics required for a method adaptive to ensure sufficient generation capacity are proposed. Additionally, a kind of capacity obligations mechanism with consideration of the annual utilization hours of generating units is developed, which can meet the above required characteristics.4. To determine the interrelated parameters in the methods to ensure the GCA, a new programming method, termed as Balance Programming between Target and Chance, is proposed. It can maximize the decision utility through weighing the quantity relation and comparing the changing velocity between the target profit and the realization chance, based on the all-around information about the effective decision front curve of the concerned problems. The effectiveness of the proposed method is demonstrated by building the bidding strategies for GENCOs with risk management in an electricity market environment.5. To construct the evaluation index system of the GCA aims to supply the early-warning system, the evaluation system of coordination between generation pannling and transmission planning as well as the effect of the relevant policies, and the direction system of effective generation investment signals, through assessing all the relevant elements in and out of the power industry, according to two dimensions, i.e. the region and the time, in the certain policy environment of energy, financial and environment protection. Considering the traits of the index, the paper adopts an integrated evaluation way with the employment of the analytical hierarchy process, the changing weighing mode based on the balanced functions, and the fuzzy synthesis.6. To ensure the mid-term GCA, a mid-term operation planning model with risk management is developed for the GENCOs firstly. And based on the model, the characteristics of UMS in the market environment are analyzed. Then a new UMS coordination model is constructed for the ISO in this paper so as to cater for the market environment. When we analyze the impact of UMS on the power system security, the GCA is taken into consideration together with the transmission capacity constrains by integrating the 'N-1' examination of lines and the concept of congestion rate. And the model may ensure the fairness among the GENCOs through the proposed coordination coefficient. In addition, the adequate solution for this model and the allocation way about the ISO's income are supplied.Finally, conclusions are made based on the research outcomes, and directions for future research indicated.