The aim of this study is to propose an array controller to demonstrate its potential in reducing the costs of tidal current energy. Tidal power is a promising renewable energy source capable of meeting the UK’s electricity needs while addressing the drive for carbon neutrality. However, production costs, limited suitable locations, and technological challenges hinder its expansion. Deployment of hundreds of tidal current turbines in an array is suggested as a future development trend. However, the complex interactions between turbines and wakes within a tidal array lead to sub-optimal power generation from most tidal turbines and result in higher fatigue loading on downstream turbines due to increased turbulence intensity in the wake reaching other turbines. This thesis is premised on the idea that designing a turbine array controller to coordinate each turbine can help reduce the cost of tidal current energy. This would facilitate the deployment of hundreds of tidal turbines in an array, steadily advancing the process and enabling it to compete with other sources of renewable electricity generation. The research question that arises is whether controlling a turbine array as a whole can increase energy output and reduce mechanical loading, consequently lowering energy costs and increasing profits. To address this research question, a 7-turbine array has been modelled and simulated. Each individual turbine has been detailed with electromechanical models spanning from the resource to the grid. Mathematical linear and non-linear programming techniques were employed using MATLAB/Simulink. The developed tidal models encompass all essential components. These 7 turbines are arranged in a staggered layout. A wake prediction model was developed for this turbine array, determining downstream flow velocity under multiple wake effects, and also taking wake transport delay into consideration. The selection of electrical architectures was compared from three aspects: power dissipation, voltage harmonics, and the cost of components. The architecture with all turbines sharing one common DC link has been chosen due to it showing the advantages of lower voltage harmonic distortion and lower costs of power converters and transformers. This study presents an array controller that determines the power and load set-points between the turbines based on incoming flow velocity for each turbine. This proposed control strategy enables dynamic responses to time-variable flow velocities and trade-offs between output power and fatigue loads by adjusting reference pitch angle and maximum power point tracking reference speed simultaneously for each turbine. Subsequently, the design of an array control has been detailed. Simulations show that fatigue loads have been mitigated while the average output power of the array over the half semidiurnal tidal cycle has increased. The response of the array controller separates into two scenarios: with or without grid requirements. In the scenario without grid requirements, the optimization depends solely on the incoming flow velocity. Results show that at low flow velocities, stabilizing load fluctuations is primarily achieved by adjusting the generator speed. Conversely, the pitch controller dominates the results of the array at high flow velocities. Under the premise of mitigating fatigue loads, the proposed control strategy still ensures high-level power extraction. The overall average output power of the entire array increases by 1.93%, and the fatigue loads on each turbine are mitigated compared to conventional MPPT control. In the scenario with grid requirements, where the amount of output power is limited by the grid, results show that the array controller is able to adjust each turbine to generate the required power. The relationship between the size of the turbine array and the effect of this array controller on output power has also been investigated. When the number of turbines equals or exceeds 5 for this specific array arrangement, the power reduction of upstream turbines can be compensated by an increase in power in downstream turbines, indicating an overall increase in array output power. In the final part of this thesis, the power quality of this turbine array under conventional control strategy and this novel array control strategy is assessed to ensure that the electricity generated by this turbine array meets grid standards. The assessment of voltage harmonics is carried out by comparing the simulation results with the standards. Simulation results show that the power quality does affect the integration of the array into the grid after the implementation of the array controller, with voltage harmonics slightly exceeding the upper limit set by the grid, thereby prompting the discussion of some possible solutions. Additionally, this study can serve as a reference for tidal energy developers.