The employment of eflergy - saving dispatching could reduce energy consumption and contamination emissions. Under the energy - saving dispatching scheme, the renewable energy units will be given the priority in the system dispatching. Then, the fossil -fueled units are dispatched based on the energy consumption and emission levels with the lowest being dispatched first. The implementation of the energysaving dispatching represents a significant change from the current practice in which each generation unit is allocated for nearly average utilization hours, and will also have some impacts on power grid companies on several aspects such as purchasing cost, system security and network planning. In this paper, a systematical analysis of these impacts is made, and some important problems to be studied are addressed.