Construction Diversion Risk Benefit Sharing And Compensation Mechanism Of Cascade Hydropower Development

Development of cascade hydropower stations has many construction advantages. Flood regulation from upstream station creates good conditions for construction diversion during flood season, which brings huge risk benefit for downstream diversion system. However, upstream regulation or flow control has corresponding influences on interests of upstream station and other subjects. The conflict and controversy among different subjects are inevitable, which brings enormous challenge to diversion scheme decision and risk management. Accordingly, around the key scientific problems of diversion risk benefit sharing and compensation under cascade construction, this research focuses on construction diversion risk estimate, determination of risk benefit, exploration to sharing and compensation method, as well as compensation mechanism design and implementation approaches. New ideas and methods are put forward for diversion risk control and distribution under construction of cascade hydropower stations. The major conclusions of this study can be summarized as follows:(1) In view of construction flood characteristics and routing rule compacted by upstream flood-regulating function, the influence of diversion section inflow by combination of upstream discharge and interval flood is described. The temporary discharge rule is introduced into flood regulation of upstream reservoir. Coupling uncertainties of upstream flood along with encounter of interval flood and discharge capacity of diversion structures, diversion risk mathematical model based on upstream flow control is established. A stochastic simulation approach is used to calculate diversion risk.The analysis of an example shows the effectiveness and feasibility of this model and method, also provides scientific means for risk benefit measurement.(2) Upstream station and downstream diversion system are seen as research objects, their costs and profits are affected by the operation mode change of upstream station. Free discharge scheme is selected as the reference point. Flood risk cost and power loss of upstream, investment profit and schedule profit of downstream are calculated quantitatively. Benefit assessment standard for flow control scheme demonstrates the economic feasibility for construction diversion by upstream flow control. On the basis of it, mathematical expression and implication of diversion risk benefit are determined, which provides data support for the research on risk benefit sharing and compensation.(3) The necessity of diversion risk benefit sharing under the cascade hydropower stations is proposed from the perspective of competition and cooperation, A model for risk benefit based on Shapley method from cooperative game theory is set up, which synthetically considering the contribution for earning profits, risks and input costs. The result calculated by Shapley method can be modified by the weights of three indexes determined by semi-structural fuzzy mathematics theory. It provides a new method for the risk benefit sharing, as well as a feasible basis for further research on risk benefit compensation method and compensation mechanism.(4) Upstream flood control affects outputs of upstream power station, thereby affecting the power load organization in local grid system. Due to the load transfer function of peak load dispatching power station and its external effect, benefit sharing is taken for an effective means for internalization of external effect. Sharing benefit among upper-lower stations and peak load dispatching power station is regarded as a kind of trilateral cooperative game. Least core in cooperative games is applied to mathematical modeling for solving problem of construction diversion risk benefit sharing of cascade hydropower stations. The method and theory are provided to solve the profits distribution conflict among cascade hydropower stations and power networks during diversion period.(5) Compensation is a kind of payment behavior, which aims to implement risk benefits sharing. Based on principle-agent theory and incentive constraint mechanisms, a risk benefit compensation model under the cascade hydropower stations is established, coupling discharge volume, risk, investment and other variables. The diversion risk benefit compensation framework and procedure for cascade hydropower exploitation is built up. Some related policy suggestions are put forward to implement benefits compensation. All of these discussions provide analyzing methods and ideas for the innovation of compensation management mode and system.