For marine renewable energy conversion to achieve a much needed step change in cost reduction, whilst proving to be cost effective and a reliable source for electricity supply, a number of major engineering challenges need to be addressed. The biggest challenge relates to the scaling up of the power capture interface (device level) and new approaches to the station keeping system (physical environment) which in turn is governed by the characteristics of the resource. In order to achieve technology cost reduction, it is envisaged that the development of marine renewable will emulate the development practices adopted in the early days of the wind energy industry and embark on building and deploying larger diameter rotors to increase device capacity and through this deliver lower unit costs. The challenge however relates to managing the resulting consequences on structural loadings. These increase with the square of the diameter of rotors/ power capture interface. As such, this approach will result in the materials used in the power capture interface operating under very high loading conditions.Evidence to date indicates that all large horizontal axis rotor systems greater than 15m diameter, which have been deployed in full scale tidal environments, have succumbed to catastrophic rotor blade failure. Hence, there is a serious Materials challange in developing more robust materials for the operating environment. By combining expertise in Tidal Energy and Materials Science, this project aims to tackle this issue, through a combination of laboratory testing and modelling.

The research will investigate the feasibility of extracting energy from low velocity (< 2 m/s) tidal flows, using the UK waters as a case study. Existing research and commercial developments have focused on the energy extraction from high velocity flows (> 2 m/s), given the priority has been to optimise the potential renewable energy. However there are numerous issues associated with the associated technologies relating to the operation, reliability, maintenance and survivability of turbines in these high energy flows. Consequently, there is now a need to consider the potential energy from low velocity tidal currents, where some of these issues will not be so paramount and the resulting energy costs make this option economically attractive. Given the different tidal conditions, it is imperative that a feasibility study is first undertaken to analyse the environmental conditions and determine the design parametrics required for a tidal stream turbine to operate in such low velocity flows. The study will therefore provide information to the tidal turbine developers on the design requirements for a low velocity tidal stream turbine, including the blade geometry and the drive train system as well as a Levelised Cost of Electricity (LCOE) evaluation for comparison with existing technologies.

This project aims to demonstrate at model-scale a novel technology to reduce unsteady-loading for tidal turbines, improving resilience and reliability, and decreasing the levelised cost of energy. Tidal energy is a promising renewable energy source that can contribute to providing energy security to the UK. The first and second array of tidal turbines has now been deployed in Scotland, confirming the UK as a world leader in this emerging energy sector. One of the main technical challenges of harvesting energy from tidal currents is the large load fluctuations experienced by the blades. These can result in fatigue failures of the blades and in power fluctuations at the generator that must be smoothed before power can be provided to the grid. The aim of this project is to develop a technology that cancels the unsteady loading at its source, while adding minimal complexity to the turbine to ensure high resilience and reliability of the overall system. The technology currently adopted to mitigate load fluctuations in air, such as that one employed by wind turbines and aerial vehicles, is not directly transferable to tidal turbines because of the harsh marine environment and the high hydrodynamic loads. For example, complex systems requiring hinges with bearings would be subjected to fouling and would reduce the blade reliability. To address this issue, we would consider introducing local flexibility that does not affect the key structural elements of the blade, and whose displacement can mitigate load fluctuations. The lowest loaded part of the blade is the trailing edge, and this is also where the smallest shape morphing can lead to the largest changes in the overall load. We could manufacture a blade made of the same material as a conventional rigid blade (fibreglass) but with a structural design that allows the trailing edge to bend to react to flow changes. To ensure high reliability of the system, we could exploit passive deformation without sensors and actuators. The small inertia of the part of the blade that bends would enable a prompt reaction to flow fluctuations. Our preliminary studies showed that a blade with a flexible trailing edge can theoretically mitigate more than 90% of the load fluctuations without affecting the mean power output. This project aims to verify these initial results by testing model-scale prototypes. We aim to design and manufacture two sets of 0.6 m and 1.2 m span blades to undertake fluid dynamics tests on a model-scale turbine and fatigue tests, respectively. These tests will demonstrate the efficacy, robustness, resiliency and reliability of morphing blades. The project includes key tidal and wind energy technology companies: SIMEC Atlantis Energy, Orbital Marine Power, Nautricity, Nova Innovation, Schottel Hydro, ACT Blades and Wood Group. Together with these industrial partners we aim to investigate the applicability of morphing blades to different tidal technologies, from 70 kW to 2 MW, from 4 m to 20 m diameter, and both seabed mounted and floating turbines with single and multi rotors. If proven effective for tidal turbines, we would also explore with our wind energy partners (ACT Blades and Wood Group) whether this technology is suitable to complement or replace some of the existing unsteady load mitigation technology currently adopted by wind turbines. Morphing blades could contribute to reduce fatigue loads, to increase reliability and lifetime yield, and hence to reduce the levelised cost of energy. It is envisaged that this technology could be more suitable for offshore wind turbines than onshore wind turbines because of the higher relative importance of component reliability. Overall this project aims to investigate the suitability of morphing blades to mitigate unsteady loads on tidal turbines, aiming at decreasing costs of blades and increase the energy yields, and thus decrease the overall cost of tidal energy.

Efficient and effective manufacturing supply networks (MSN) are essential to the functioning of the global economy. In line with the EPSRC call, this proposal is premised on the strong belief that appropriate mathematical theory and methods can provide fundamentally new understanding on the behaviour of MSNs and provide an effective investigative toolset for MSN analysis, design and management. In particular we argue that the power of network science can be harnessed to underpin new thinking in MSNs for resilience and robustness. The work will be strongly embedded in real MSNs in three domains - producer-driven inbound MSNs and outbound distribution channels for industrial companies; global MSNs for critical products used in high-valued manufacturing (e.g. titanium or composite pre-preg materials); and evolving MSNs for emerging UK industries such as renewable energy. The project will develop and apply existing and new mathematics specifically in the theory of complex adaptive networks, drawing on techniques from game theory, dynamical systems and Bayesian informatics. It will also learn from related modelling approaches in ecology, metabolism modelling and utility grids. This grant will represent the first attempt to develop an integrated mathematical modelling suite to support effective decision making in MSNs in the context of risk and uncertainty. The work will build on disparate recent developments in network science and complex adaptive dynamical systems, Bayesian statistics and operational research to develop new models and measures to better understand and analyse MSN behaviour and performance. Multiple perspectives and a multi-level view of risks and vulnerabilities in MSNs will be taken, including physical, financial, informational, relational, and governance perspectives at the strategic MSN design and policy levels, and risk mitigating strategies at both strategic and operational levels to support MSN management. This is an adventurous and challenging proposal due to the following reasons: (1) The PIs based in have various domains of expertise, from theory of complex networks and nonlinear dynamics, to applied statistics in domains such as reliability and risk assessment, and development and application of operational research and operations management methods to MSN management and control problems. However, our expertise is complementary and will add a substantial body of new knowledge and bring novelties to the theory of complex networks, network dynamics and Bayesian networks, but also, applications of these new models to real-world MSN problems will ultimately lead to better understanding of complex MSN behaviour and will improve MSN management and control in the presence of risks and uncertainties. (2) This proposal will bring together PIs and PDRAs from 4 universities. The management of the resources involved is a challenge on its own. However, we believe that a very carefully designed project management plan can lead this research collaboration to its success. Furthermore, if funded, this research project can potentially secure the continuation of the collaboration among the four universities. (3) The project will involve a wide array of industrial partners from manufacturing primes (e.g. in Aerospace and Defence) to manufacturing trade organisations and consultants, to representatives of a brand new industry (offshore renewable energy) for which the in-bound MSNn does not yet exist.

The research will investigate the nature of the loading patterns imparted onto tidal stream turbines when positioned and operated within an array and develop operational procedures to mitigate the impacts of these extreme loading patterns. Exposure to open sea wave climates with high wave-current interactions will influence the power generating, structural integrity, product durability and maintenance requirements of the technologies deployed. The research will undertake both experimental and numerical analyses in a manner that will make the results and findings transferable to real-life implementations. This will inform developers of the peak and fluctuating loads that devices are exposed to in a commercial array environment and will also identify and test mitigating actions to be implemented in order to ensure the robustness and sustainability of the array. The dynamic, cyclic loadings on a tidal stream turbine have been shown to depend on the current profile and wave characteristics which can increase the severity of these loads. This must be considered in the design of the turbine. A turbine in an array will be subjected to more complex flows due to its position in the array, which will result in more diverse loading patterns, which must be fully understood by the turbine designers and operators. The project will therefore evaluate and measure the loading and performance of different configurations of tidal stream turbine arrays using numerical modelling and model scaled experiments. The numerical modelling will use fluid and structural modelling. An existing and proven, instrumented, laboratory scale turbine design will used for the tests. Initial work on a three turbine array will be undertaken to create models of a full-scale turbine array to determine the power output, loading patterns and accurate life-fatigue analysis based on realistic site deployment conditions. This information will be formulated to provide a basis for the industry to evaluate anticipated performance, monitoring needs, operational best practice and maintenance regimes in order to deliver the lowest cost of energy from tidal arrays