This project will use two niche applications to bridge the gap between academic excellence and industrial progress in the development of efficient pure electric power take off in wave energy converters. Compared to electrical machines in other industrial sectors, wave energy converters are slow which has led to a range of novel generators being developed, yet comparatively few have been demonstrated at full scale with developers instead preferring to use conventional generators connected via device specific mechanical linkages. Pure electric drive train concepts are known to be efficient and mechanically simple but must now be proved feasible and advantageous at a meaningful device scale. If the electrical generator is allowed to run flooded with sea water, there will be no requirement for sealing and therefore a much reduced requirement for maintenance. The concept must be demonstrated at sea whilst the performance is monitored. Investor confidence must be gained in the technology by accruing many hours of operational data. Long term operational issues of corrosion, biofouling, reliability and condition monitoring must be tackled. Newcastle and Edinburgh Universities have been at the forefront of UK academic work in electric drives and wave energy converters for decades, and this collaborative team will now deliver two niche application prototypes to demonstrate all electric drive trains for wave energy converters. The project will design and demonstrate direct drive power take off for subsea communication networks and also powering subsea equipment for the oil and gas industry. A full scale electrical machine will be demonstrated using experience provided by an industrial partner. In addition, submerged electric generators will be demonstrated at sea for 12 months using Newcastle's USMART acoustic network gateway buoy. Corrosion protection and antifouling techniques specifically for the electrical generator will be demonstrated first in the laboratory before being used in the ocean.

Although there is a long history of research of wave energy convertors (WECs), there are still many challenges that make it difficult to develop effective, reliable and economically viable WECs. One of the challenges is the lack of robust modelling tools to assess survivability of WECs under extreme marine environments that cause extreme loads and large responses. Survivability of WECs needs to be concerned not only in the design stage but also when operational to maximise the amount of harnessed energy and minimise the risk of damage. To assess and analyse the survivability of WECs, one must identify survival conditions, quantify loadings and responses of WECs and characterise the pressure and velocity field of WECs under survival conditions. Identification of survival conditions for WECs requires not only the consideration of severe storms but also of loads and responses of WECs in shorter steep seas, which is different from that for other offshore structures that may just need to consider severe storms giving the largest wave heights. High precision quantification of loadings and responses of WECs must consider wave breaking and viscosity, which will provide dominate factors for conceptual design and to determine if the device needs to be shut down. Characterisation of the pressure and velocity fields of WECs needs to resolve two-phase flow with vortex structures to sufficient detail, which will provide information for structural and components design. In addition, as the waves in the survival conditions are highly nonlinear, they must be simulated for a long propagating duration in a large domain to allow them to sufficiently evolve. Therefore, the numerical modelling tools for analysing WEC survivability should have the capability of dealing with breaking waves and two-phase flow and accurately estimating the effect of viscosity in turbulent states. In the meantime, the tools must be fast enough so that engineers can simulate the cases within practical time-scales for design. Many numerical models with various levels of accuracy and efficiency exist, but none of them can adequately deal with the extreme conditions found in practice. Some models are phase-averaged, being computationally efficient but not sufficiently accurate. Some models are phased-resolved, based either on the potential theory or the viscous theory. The most advanced potential models are fully nonlinear and much faster than viscous models, but could not deal with wave breaking and turbulence which always occurs for WECs. The viscous models can theoretically deal with the physical phenomena but are generally very computationally expensive, perhaps also suffering from unwanted numerical dissipation. This project will develop a novel numerical modelling suite by combining different models and by proposing new numerical approaches and machine learning techniques, which will be more accurate and require less computational effort. The modelling suite will be able to automatically go up to fully nonlinear simulations and down to linear simulations depending on the level of nonlinearity of waves and their interaction with the WECs. The new modelling suite will be validated by data measured from WEC models in the laboratory and real devices at sea, and will be applied to assess the parameters relevant to the survivability and reliability of WECs. During the project, an advisory board will be set up to give the suggestions on specific research topics, and regular project meetings/workshops will be held to attract the interests of WECs stakeholders and disseminate the research outcomes. Our project partners will be invited to be a member of the advisory board and to attend or contribute to the meetings/workshops. Databases for different types of WECs will be created during this project, which will be accessible by general public.