A control system implementing a hybrid energy storage system (ESS) optimization strategy is disclosed. The hybrid ESS optimization strategy may be implemented in a machine that comprises a power system that includes a plurality of power sources and a power controller that includes one or more processors. The power controller may receive information related to a set of brake-specific fuel consumption (BSFC) maps associated with the plurality of power sources, determine a performance indicator using a cost function associated with the plurality of power sources, and generate a command to operate the power system based on a power distribution that minimizes an energy cost to operate the power system based on the information related to the set of BSFC maps, the performance indicator, and a load associated with the power system.