An apparatus and method for boosting output of a generator set are provided. The output of the generator set is connected to an electrical load. The apparatus includes an energy storage unit, and a power-electronic unit. The energy storage unit uses batteries and capacitors to store electric energy. The power-electronic unit measures an electrical parameter of the output of the generator set. Based on the measured electrical parameter and a predefined criterion, the power-electronic unit determines additional energy required by the electrical load. Thereafter, the power-electronic unit supplies the additional energy to the electrical load. The additional energy is drawn from the energy storage unit.