Economic load dispatch (ELD), used as part of the modern energy management system basically minimizes the total generation fuel cost of thermal plants while satisfying various system constraints. However, ELD alone is not sufficient to reduce the pollutant emissions caused by fossil fuel burning for power generation. Thus, it becomes necessary to implement economic emission dispatch (EED) model, which aims to minimize both generation fuel cost and emissions simultaneously. Myanmar Power System is used as a case study in this model. The types of emissions considered in the study are carbon dioxide (CO ) and nitrogen oxides (NO V ). A practical ramp-rate of turbine generator units is also formulated and studied in the model. Total emission constraint on the whole system is further implemented to investigate the effect of emission limit on the variation of generation schedule among generating plants.
It is found that whenever minimum cost of operation is taken as sole objective in the model, the corresponding emission level increases. Similarly, minimum emission dispatch results in higher operating cost. Therefore, both objectives are conflicting in nature and some weights must be assigned to obtain a non-inferior solution. The case where the ramp-rate is considered in problem formulation incurs higher cost than that without it. Several trade-off curves obtained can be taken as guidelines to fix the desired level of cost and emission together by the operators.