A power system and a method for energizing an electrically heated catalyst are provided. The system includes a controller that generates a first control signal to set a switching device to a first operational state if the first temperature level downstream of the catalyst is less than a threshold temperature level and the engine is being decelerated. The controller further generates a second control signal to induce a generator to output a second voltage if the first temperature level is less than the threshold temperature level and the engine is being decelerated, such that the second voltage is applied through the switching device in the first operational state to the catalyst to increase a temperature of the catalyst.