Large scale power generation from tidal currents will require the deployment of large numbers of tidal turbines arrayed in close proximity to one another. This presents significant challenges; turbine-in-wake interactions, as well as significant opportunities; arraying turbines side-by-side in closely spaced fences can significantly enhance their performance. Extreme weather survivability and the ability to maintain offshore systems are key to delivering economic and durable tidal energy systems.

A potential solution to these challenges is floating systems supporting multiple closely spaced turbines. Such systems will provide rapidly deployable, retrievable and maintainable multi-turbine systems that deliver high performance.

This project will conduct a preliminary assessment and feasibility study of floating closely spaced tidal turbine arrays. Specifically the project will seek to optimize the hydrodynamic performance of multiple closely spaced turbines supported from a single platform and determine their load and response when subjected to combined wave and tidal flows. The project will also seek to determine the suitability and stability of mooring systems under such loads and the platform's static and dynamic response leading to definition of permissible operating regimes.

Potential Impact:
This project addresses novel infrastructure to facilitate cost-effective deployment of tidal stream turbines at commercial scale. This will support the development of the UK and Chinese tidal stream energy industries by demonstrating confidence in the future technical and economic potential for large-scale generation. We will conduct fundamental research to underpin the development of floating structures to support multi-turbine fences. This approach to turbine deployment offers the potential for marked reduction of cost of tidal stream energy through increased performance and reduced lifetime cost resulting from reduced maintenance costs etc. Specific technical outputs will include:
i. Hydrodynamic optimization of short fences of tidal turbine arrays together with performance and loads resulting from operation in combined tidal flows with waves.
ii. An engineering model to assess the suitability, stability and safe operating limits of floating tidal turbine systems.

Direct beneficiaries will include both the industrial and academic parts of the tidal energy sector, whilst the wider beneficiaries include society as a whole through the provision of cleaner, more affordable renewable energy. As well as the social and economic impact of supporting a developing industry sector, the project will enhance both UK and Chinese research reputation, capabilities and skills. The methods and understanding of the fundamental flow and fluid-structure interaction problems that will be delivered by this project will underpin the evolution from single seabed supported to multi-turbine floating platforms, and will help to promote UK and Chinese academia and industry to the forefront of the marine energy industry.

The UK and Chinese governments are committed to the commercialisation and wide spread deployment of tidal energy devices. The multi-turbine deployments investigated in this study will provide high performance with reduced costs associated with cheaper mooring foundation systems, leading to substantially reduced cost of energy, which is aligned with both government's renewable energy development policies. This project will lead to increased UK-China collaboration in an area that has been identified as a high priority area by both nations.