Startup and Shutdown Problem of Thermal Generating Units with Constrained Total Nitrogen Oxides Emissions （Part 5）−The case of Including a pumping-up Power Station−

In this paper, our series of reports on the question of “Startup and Shutdown Problem of Thermal Generating Units with Constrained Total Nitrogen Oxides Emissions” is expanded to cover the case of including a pumping-up power station, and we describe the calculating method used for this problem. We test our method by a model system, and consider its appropriateness. It is shown that when we simply apply the convenient rule of “generating operation at peak load, and pumping operation at base load”, we fail to find the optimum operation. We show that the reason for this failure is the change of unit commitment and the value of the emission constraint. Using curves of the total cost versus total emission constraint for both the case of including a pumping-up power station and that of not including it, we show that the operation of a pumping-up power station is also useful under the total nitrogen oxides emission constraint for the thermal power plants