Tidal power plant technology is becoming increasingly mature and the use of power-plant arrays attracts more interest. It is therefore relevant to study how power plants affect each other in arrays and possible other structures in for example multi-purpose platforms. The Deep Green technology is a novel technique that is suitable to use in moderate tidal flows. It is promising since larger areas of tidal flow generation can be used and makes it also suitable for multipurpose platforms. Large eddy simulations (LES) is used to study the turbulent flow with and without Deep Green for a specific site. The power plant is modelled using the actuator line method (ALM) here implemented to allow for arbitrary paths or trajectories. The ability to model arbitrary paths is necessary since the Deep Green is not stationary but moves in a lying figure-eight trajectory. The flow disturbances downstream of the power plant are studied with respect to velocity and power deficit, and turbulence intensity. The trajectory width Dy is found to be an appropriate reference length scale to describe the persistence of these disturbances. The power deficit is approximately 10% at 10Dy downstream of the Deep Green, and the turbulence intensity is increased by almost a factor of two compared to undisturbed conditions. It is further noticed that the power plant, besides affecting the flow in the general tidal flow direction, directs the flow downwards to some degree and therefore increases the bottom shear locally.