Ocean Thermal Energy Conversion (OTEC) offers an interesting alternative for reducing the use of fossil fuels for energy generation. Using the temperature gradient present between the surface water and deep water, it is possible to produce electricity through a thermodynamic cycle. At present, the experiments are limited due to a relatively high cost. A fundamental approach is developed with the creation of numerical models in steady and dynamic state. The model in steady state has been developed from a simplified mathematical description of the components of the cycle. This model allows for an overall assessment of system performance including the withdrawal and discharge of the sea water, as well as the thermodynamic cycle. From the static model, a dynamic model was established using the method of the equivalent Gibbs systems. This tool is used to describe the start-up and shutdown, to study the modulation of the electrical power delivered to the network and to optimize the cycle. The simulation results of the different models are confronted with the literature and experimental data in order to have points of validation. One of the advantages of the model under dynamic conditions is the ability to perform an analysis of the "first and second principle" of the system. Optimization of the operation is carried out from this analysis. Possible improvements are proposed. An optimization of the cycle operation is carried out from this analysis. The optimization is done by coupling the dynamic model with the tool Genopt. The numerical tools developed will permit in addition to develop strategies to control of the power plants.