With the serious concern for environmental problems, the exploitation of renewable energies is becoming a need and no longer a choice, offshore wind energy is one of the trends in the renewable energy market. The exploitation of this energy demands important investment costs that’s why optimizing the wind farm layout is primordial to make a cost effectiveness during the lifetime of the park. Otherwise, minimizing the Levelized Cost Of Energy (LCOE) is the key to have the tradeoff between wind farm cost and the annual energy delivered to the terrestrial network. For a realistic framework, the wind farm losses must take into account the wake losses between turbines so a calculation tool of wake effect is developed in this paper.