Nowadays, more than 50% of the fuel energy is lost in CNG Engines. While efforts to increase their efficiency have been focused mainly on the improvement of the combustion process, the combustion chamber and the reduction of friction losses, heat losses still remain the most important inefficient factor. A global strategy in which several energy recovery strategies are implemented could lead to engine improvements up to 15%. Therefore, the development of accurate models to size and predict the performance of the integrated components as well as to define an optimized control strategy is crucial. In this contribution, a model to analyze the potential of a new powertrain based on the electrification of the main auxiliaries, the integration of a kinetic energy recovery system and the exhaust gases heat recovery through a thermoelectric generator and a turbo-component is presented. The determination of the most suitable configuration, the optimum control of the system and the benefits in terms of fuel saving for a target driving cycle are possible with the model. In addition, its modular structure enables the prediction of the influence of any condition change not only in the components but in the system as a whole. In addition, effects like the increase of the backpressure on the consumption can be analyzed. The model is still in its design phase and although more information is required, estimations for example at the design point (1500rpm, 500 Nm and 90km/h), of an electrical production up to 3 kW and a fuel saving of 3.6%, can be done.