One of the key developments of the marine energy industry in the UK is the demonstration of near commercial scale devices in real sea conditions and the collection of performance and environmental data to inform permitting and licensing processes.The ETI’s ReDAPT (Reliable Data Acquisition Platform for Tidal) project saw an innovative 1MW buoyant tidal generator installed at the European Marine Energy Centre (EMEC) in Orkney in January 2013.The project demonstrated the performance of the tidal generator in different operational conditions, aiming to increase public and industry confidence in tidal turbine technologies by providing a wide range of environmental impact and performance information, as well as demonstrating a new, reliable turbine designThis document provides an overview of the second year of operation and the post-test inspection of the DEEP-Gen IV tidal turbine. At the time of writing, the DEEP-Gen IV turbine had completed two years of operation over seven deployments at Berth 2 at the EMEC. Having generated & exported over 1.2GWh to the Scottish grid the turbine was retrieved and underwent a series of inspections to maximise the learning after an extended period of operation. The report covers both detailed turbine performance data but and data on the environment and the interaction of the turbine with the environment. A discussion is presented of how the performance of the DEEP-Gen IV turbine accorded with current industry view of the Levelised Cost of Electricity (LCOE) and then the key challenges in achieving more ambitious targets. An assessment of the power quality performance is presented along with a summary of supply interruptions at the Eday substation. Information has also been gathered on the performance of materials and coatings in terms of biofouling and corrosion. Other lessons learned are presented in the areas of programme management, marine operations, maintenance activities, testing activities, daily operations and EHS management.