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Abstract: During the past two decades, in particular the past decade, there has been a rapid rate of development of hydropower in China. It is foreseeable that the same rate of development will be maintained in the next decade. The total installed generation capacity of hydropower in China has now surpassed 200GW and ranks first in the world. The unprecedented rate of expansion, development scale, emergence of large number of hydro plants with high head and huge capacity, and electric power transmission have led to significant changes in management and operation of large-scale hydropower systems which have become one of the significant factors in constraining the security and economic operation of power grid in China. This article gives an overview of the China''s hydropower, analyses the new challenges that it faces, highlights the key scientific and technological issues that need to be solved, and pinpoints that the solution of these problems will be the key to the realization of energy saving and emission reduction by China in 2020. [Copyright &y& Elsevier]

Because of the growing demand for energy in recent years, multireservoir system operation with a power deficit aspect is becoming an increasingly important problem in electrical power systems. To satisfy this practical requirement, a min-max linear programming (LP) model is developed to determine the optimal generation of all the hydroplants so as to equally distribute electricity shortage in the scheduling horizon. The objective of the LP model is to minimize the maximum, rather than the traditional variance function, of residual load series that is obtained by subtracting the total outputs of all the hydroplants from the original load curve. Also, in the modeling process, the LP model takes a set of necessary operation constraints into account. The proposed model is applied to a classical multireservoir system with 10 coupled reservoirs. The results indicate that the proposed LP model outperforms several existing methods in smoothing the power deficit. Thus, a new perspective is provided for the operation of hydropower systems in the cases where the water head can be assumed to be a constant. [ABSTRACT FROM AUTHOR]

As an important renewable energy resource, hydropower plays an irreplaceable role in reducing power shortages in modern electrical systems throughout the world. This study focuses on the fixed head hydropower operation problem considering power shortages, which is classified as a large-scale nonlinear constrained optimization problem with a set of complex operational constraints. In order to efficiently solve this problem, a novel quadratic programming (QP) model is developed, in which the goal is to find the optimal hourly operational policy for all hydropower plants in a system so as to minimize the sum of squared energy deficits over the scheduling horizon. The results of a ten-reservoir hydropower system show that the proposed approach can efficiently find better solutions than several previous optimization methods for energy deficit reduction. Thus the proposed technique is effective for hydropower scheduling problems in which the assumption of fixed hydraulic head holds. [ABSTRACT FROM AUTHOR]

Abstract To satisfy the huge energy demand of China, a rapid development rate of hydropower system was undertaken over the past decades. Currently, thousands of hydropower reservoirs with a total installed capacity of more than 330 GW have provided approximately 20% of China's gross electricity generation, ranked number 1 in the world. Besides, it is foreseeable that in the coming decades, the same development speed of hydropower will be maintained in order to effectively handle the increasing environment and energy problem. The dimensionality problem caused by booming system scale, unprecedented development speed and operational complexity are posing a giant challenge to the operation of large-scale hydropower system in China. Thus, after giving an overview of China's large-scale hydropower system, this paper deeply analyses the key operation characteristics leading to the dimensionality problem and highlights the possible dimensionality reduction strategies to sharply alleviate the optimization difficulty, providing necessary technical support to achieve the goal of energy conservation and emission reduction of China. To sum up, this paper could be a good and inspiring example, contributing to the sustainable development of worldwide countries with a high proportion of hydropower integration. Highlights • An unprecedented large-scale hydropower system is forming in China. • The main operation characteristics of large-scale hydropower system are given. • The dimensionality problem is a great challenge to China's hydropower operation. • Several dimensionality reduction strategies are used to reduce modeling difficulty. [ABSTRACT FROM AUTHOR]

The power industry is playing an increasingly important role in the world economy, and insufficient power supply may lead to huge enormous economic loss throughout the world. Then, the problem of power shortage is receiving a great deal of attention from operators and managers in electrical power system. With the merits of fast startup-shutdown, hydropower is regarded as one of the most reliable renewable energy sources to smooth the electricity shortage of power grid. Thus, this paper focuses on the operation of head-sensitive hydropower system considering power shortage aspect. To effectively address this problem, a novel method based on linear programming and successive approximation is proposed, where the initial hydraulic heads of each hydroplants is generated based on the actual working condition, and then the linear programming method is used to solve the fixed-head hydropower optimization problem involving a carefully-designed min-max optimization objective, while the successive approximation strategy is employed to incrementally improve the solution's quality by dynamically updating water heads of all the hydropower plants. The simulations demonstrate that compared with the original load demand, our method can make an average of approximate 20% reduction in electricity shortage of power system, demonstrating its effectiveness and practicability. [ABSTRACT FROM AUTHOR]