Tidal current and wave power have made substantial progress towards commercialisation. Based on the successful testing of full-scale prototypes, pioneering tidal arrays are currently implemented by means of direct agreements between developers/investors and device manufacturers. The top-ranked risks for commercial projects (identified as achieving funding and uncertainty in device performance) are directly intercorrelated as investor confidence mainly depends on track records of continuous device operation. Before becoming recognised as a fully mature electricity generation method, marine energy needs to prove a range of referenceable project cases. The attainment of this array-scale success will represent a major turning point for the global marine energy business and is expected to finally trigger large-scale deployment.