The present method proposes the use and adaptation of ocean circulation models as an assessment tool framework for tidal current turbine (TCT) array-layout optimization. By adapting both momentum and turbulence transport equations of an existing model, the present TCT representation method is proposed to extend the actuator disc concept to 3-D large scale ocean circulation models. Through the reproduction of experimental flume tests, this method has shown its ability to simulate accurately both momentum and turbulent wake interactions. In addition, through an up-scaling test, this method has shown to be applicable at any scale. Thanks to its short computational time, the present TCT representation method is a very promising basis for the development of a TCT array layout optimization tool. Furthermore, on the basis of the simulations performed for the present publication, a reflection on the quantification of the array layout effects on power assessment and device deployment strategy has been initiated.