Integrating renewable energy into standalone Internal Combustion Generator (ICG) systems is an economical and eco-friendly option. However, previous studies demonstrate the difficulties in replacing the ICGs completely by using Solar PV (SPV) and wind energy with a dispatchable energy storage. This makes it interesting to analyze the limitations in integrating the SPV and wind energy into Hybrid Energy System. A multi criterion analysis is presented in this study, considering Levelized Energy Cost, Loss of Load Probability, and Fuel Consumption varying the scale of the ICG capacity to attain aforementioned objective. Changes in the system design with the integration of the SPV and wind energy were analyzed using Pareto multi-objective optimization considering Renewable Energy Capacity as an objective function. Sensitivity of the ICG capacity on optimum Renewable Energy Technology, role of the ICG in improving system reliability, etc., were subsequently analyzed. The results depict that the ICG capacity notably influence to the balance between wind and SPV capacity. An increase in the ICG capacity does increase the contribution from dispatchable energy source in most of the scenarios. Furthermore, it facilitates to amalgamate highly fluctuating renewable energy sources at a relatively low cost. This makes it inevitable to replace ICG with non-dispatchable renewable energy sources and energy storage.