Optimal operation of industrial cogeneration for load management

This paper presents a generalized formulation to determine the optimal operating strategy of industrial cogeneration schemes. The model includes both electrical and thermal systems. All types of cogeneration equipment viz steam turbines, gas turbines, diesel generators, steam boilers, waste heat recovery boilers, and steam header configuration, with grid connection are separately represented in terms of their characteristics so that the model has the flexibility to be applicable for any industry. The model is multiperiod and nonlinear in nature and utilizes a Newton based algorithm for minimizing the total operating cost. Optimal operating strategies for different equipment combinations for a typical industrial configuration under different electricity tariff rates are determined using the proposed model. The results show that industrial cogeneration has a significant potential in reducing peak coincident demand. The optimal response of cogeneration plant reduces the peak coincident demand by 42.8 MW (71%) under flat tariff and 54 MW (90%) under TOU tariff. The industry gets 16% saving in the total operating cost with the optimal operation of the cogeneration plant. When power export is permitted to grid, it provides the utility a peak saving of 63.7 MW.