Coordination mechanisms for planning of hydro-thermal subsystem

This paper studies the planning problem of hydro-thermal system, which is motivated by the practical system in the Yellow River Basin of China. The problem is formulated as one multistage stochastic optimization problem. It has the high-dimension, dynamic, nonlinear and stochastic characteristics. The solution approach is nonlinear stochastic dual dynamic programming(NSDDP) which is based on the approximation of the expected-cost-to-go function of stochastic dynamic programming by a piecewise linear function. For the sake of easy practical management, two coordination mechanisms, annual consumption quota and minimum flow limit, are explored. These two mechanisms also enable to solve the problem in a distributed way and hence improve the scalability of the NSDDP algorithms. Numerical results in case study are presented to illustrate the effectiveness and efficiency of the coordination mechanisms for hydro-thermal system planning.