Many countries have set ambitious renewable energy targets with offshore sources anticipated to form an important part of this; for example, it is estimated that one fifth of the electrical supply in the UK could come from marine (wave and tidal stream) resources. However, the environmental impacts of tidal turbines on marine wildlife (particularly seals, whales, and dolphins) is largely unknown. One major concern is the potential for marine mammals to collide with the rotating turbine blades causing injury or death. It is critical to learn whether this concern is valid by collecting data on the underwater movements of marine mammals around operating tidal turbines. Collecting these data is extremely challenging and available methods for measuring movements of marine mammals underwater and interactions with tidal turbines are limited. However, a small number of cutting-edge technologies have the ability to detect and track marine mammals underwater; these are underwater video, and active- and passive-acoustic tracking. This project will design and build a standardised marine mammal detection and tracking system based on the integration of this suite of technologies for the tidal energy industry. The system will be designed to be standardised in terms of the data collected but will be flexible to ensure it can be integrated into a range of different tidal turbine designs and can be deployed in a variety of different tidal environments. Effectively, the system will be designed to be 'plug and play' so that it can be integrated easily with future tidal turbines, and can be deployed and retrieved with minimal impact to turbine operation. Further, to ensure that the data collected by the system is standardised and therefore comparable between future monitoring studies, a series of open source and freely available data archiving and analysis tools for the datasets will be provided. Overall, this project aims to deliver a unique monitoring tool that will provide the Tidal Energy Industry with a data collection system that may be required as part of their consent monitoring conditions, and will provide regulatory authorities with the evidence base upon which to make informed decisions about marine mammal collision risk during the consenting process for tidal energy developments. keywords: tidal stream energy, tidal turbines, marine mammals, collision risk, impact assessments, sonar, video, hydrophones, seals, dolphins, porpoises, behaviour, underwater tracking stakeholders: Regulators, Tidal Developers, Statutory Advisors, Scottish Government, Scottish Natural Heritage, Natural Resources Wales, Atlantis Resources Ltd

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.

Computational science is a multidisciplinary research endeavour spanning applied mathematics, computer science and engineering together with input from application areas across science, technology and medicine. Advanced simulation methods have the potential to revolutionise not only scientific research but also to transform the industrial economy, offering companies a competitive advantage in their products, better productivity, and an environment for creative exploration and innovation. The huge range of topics that computational science encapsulates means that the field is vast and new methods are constantly being published. These methods relate not only to the core simulation techniques but also to problems which rely on simulation. These problems include quantifying uncertainty (i.e. asking for error bars), blending models with data to make better predictions, solving inverse problems (if the output is Y, what is the input X?), and optimising designs (e.g. finding a vehicle shape that is the most aerodynamic). Unfortunately, the process through which advanced new methods find their way into applications and industrial practice is very slow. One of the reasons for this is that applying mathematical algorithms to complex simulation models is very intrusive; mostly they cannot treat the simulation code as a "black box". They often require rewriting of the software, which is very time consuming and expensive. In our research we address this problem by using automating the generation of computer code for simulation. The key idea is that the simulation algorithm is described in some abstract way (which looks as much like the underlying mathematics as possible, after thinking carefully about what the key aspects are), and specialised software tools are used to automatically build the computer code. When some aspect of the implementation needs to change (for example a new type of computer is being used) then these tools can be used to rebuild the code from the abstract description. This flexibility dramatically accelerates the application of advanced algorithms to real-world problems. Consider the example of optimising the shape of a Formula 1 car to minimise its drag. The optimisation process is highly invasive: it must solve auxiliary problems to learn how to improve the design, and it be able to modify the shape used in the simulation at each iteration. Typically this invasiveness would require extensive modifications to the simulation software. But by storing a symbolic representation of the aerodynamic equations, all operations necessary for the optimisation can be generated in our system, without needing to rewrite or modify the aerodynamics code at all. The research goal of our platform is to investigate and promote this methodology, and to produce publicly available, sustainable open-source software that ensures its uptake. The platform will allow us to make advances in our software approach that enables us to continue to secure industrial and government funding in the broad range of application areas we work in, including aerospace and automotive sectors, renewable energy, medicine and surgery, the environment, and manufacturing.

Electricity can be generated through the conversion of the kinetic energy that resides in tidal currents in a similar way to a wind turbine. The ubiquitous nature of tidal energy, and the predictability and reliability of tidal currents, gives tidal-stream energy distinct advantages compared to other renewable energy technologies. Individual tidal energy devices have been installed and proven, with commercial arrays planned throughout the world. Yet, the true global resource and ocean conditions are broadly unknown, affecting optimal global device design. Present methods are unsuitable as the industry matures beyond the fast, shallow, well-mixed, and wave sheltered "demonstration" sites - influencing investor confidence. Transformative understanding of this sustainable natural resource for the coming century is therefore needed to bring a step change towards a sustainable, high-tech and globally exportable, UK renewable energy industry. CHALLENGE 1: How much tidal energy is there in the world and how is it distributed? OBJECTIVE 1: Resolve the true tidal-stream energy resource using unique datasets, consistent modelling framework, and state-of-the-art modelling techniques. Global tidal resource assessments are based on coarse, data constrained, models that are not validated for the few tidal energy sites resolved, as developed for other applications (e.g. global energy budgets); therefore, the global tidal energy resource is only broadly known. Fine-scale bathymetric constrictions (e.g. coral reef passes), biological communities (e.g. flow diverted around kelp beds) and ocean currents, can all accelerate currents between constrictions; meaning many sites initially dismissed as commercially unviable may actually be suitable. A consistent modelling framework (e.g. resolution and physics), and comparison of modelling techniques, will be developed to reduce bias and determine the potential global resource. CHALLENGE 2: How do conditions vary globally and will this change in the coming century? OBJECTIVE 2: Realistic oceanographic conditions at potential tidal-stream energy sites for the coming century will be determined For sustainable device design, realistic oceanographic conditions must be characterised for the lifetime of deployments, and cascaded through high-fidelity device-scale models (e.g. CFD); yet oceanographic conditions, and the impact of climate change, at tidal energy sites is largely unknown. Previously unviable tidal energy regions may become economically viable in the future (as near-resonant tidal systems and their associated currents are sensitive to sea-level rise), and, due to wave-tide interaction processes, oceanographic conditions at tidal energy sites may change. Dynamically coupled wave-tide ocean-scale models will be developed to inform the developing industry (e.g. optimal and resilient design), with new techniques that can simulate the interaction between the resource and devices. CHALLENGE 3: Are current methods of suitable as the industry develops? OBJECTIVE 3: Improved methods of device behaviour in resource and environmental assessment models The industry is evolving beyond fast, shallow, well-mixed and wave sheltered sites, to areas of the world with complex oceanographic conditions (e.g. ocean currents and swell wave dominated climates). New approaches are needed to understand the interactions between devices, resource and environment. Device-scale interaction studies assume well-mixed (i.e. homogenous) channelized flows, with tidal turbine loading from waves assessed assuming waves travel in-line with tidal currents (waves following or opposing current), which is not the case beyond an extremely limited number of tidal straits (e.g. Pentland Firth). Furthermore, device interaction with the flow must also be resolved within resource assessment, beyond simplified momentum sink terms. Device behaviour and interactions will improved at both ocean and device scales.

The production, storage, distribution and conversion of hydrogen is a rapidly emerging candidate to help decarbonise the economy. Here we focus on its role to support the integration of offshore renewable energy (ORE), a topic of increasing importance to the UK given the falling costs of offshore wind generation (with prices expected to drop to 25% of 2017 by 2023) and Government ambition. Indeed, the latest BEIS scenarios include more than 120 GW of offshore wind, and even up to 233GW in some scenarios. This brings with it significant challenges to the electricity infrastructure in terms of our ability to on-shore and integrate these variable energy flows, across a wide range of timeframes. Current ORE plants composed of fixed offshore wind structures are sited relatively close to land in shallow water and use systems of offshore cables and substations to transform the electricity produced, transmit it to the shore and connect to the grid. However, in order to exploit the full renewable energy potential and requirements for the 2050 net zero target, offshore wind farms will need to be sited further offshore and in deeper waters. This brings possibilities into consideration in which transporting the energy to shore via an alternative vector such as hydrogen could become the most attractive route. Hence we consider both on-shore and off-shore hydrogen generation. Not only can hydrogen be an effective means to integrate offshore wind, but it is also increasingly emerging as an attractive low carbon energy carrier to support the de-carbonisation of hard to address sectors such as industrial heat, chemicals, trucks, heavy duty vehicles, shipping, and trains. This is increasingly recognised globally, with significant national commitments to hydrogen in France, China, Canada, Japan, South Korea, Germany, Portugal, Australia and Spain in the last three years alone, along with the recent launch of a European hydrogen strategy, and the inclusion of hydrogen at scale in the November 2020 UK Government Green plan. Most of the focus of these national strategies is on the production of 'green' hydrogen using electrolysis, driven by renewable electricity. However, there remains interest in some countries, the UK being one example, in 'blue' hydrogen, which is hydrogen made from fossil fuels coupled with carbon capture and storage and hence a low carbon rather than zero carbon hydrogen. Today, 96% of hydrogen globally is produced from unabated fossil fuels, with 6% of global natural gas, and 2% of coal, consumption going to hydrogen production, primarily for petrochemicals, contributing around 830 million tonnes of carbon dioxide emissions per year. Currently green hydrogen is the most expensive form of hydrogen, with around 60-80% of the cost coming from the cost of the electrical power input. A critical factor that influences this is the efficiency of the electrolyser itself, and in turn the generator used to convert the green hydrogen back into power when needed. In this work we focus on the concept of a reversible electrolyser, which is a single machine that can both produce power in fuel cell mode, and produce hydrogen in electrolyser mode. Electrolysers and fuel cells fall into one of two categories: low-temperature (70-120C) and high temperature (600-850C). While low temperature electrolyser and fuel cell systems are already commercially available, their relatively low combined round-trip efficiency (around 40%) means that the reversible solid oxide cell (rSOC), which can operate at high temperatures (600-900C) is of growing interest. It can achieve an electrolyser efficiency of up to 95%, power generation efficiency of up to 65%, and hence a round-trip efficiency of around 60% at ambient pressure using products now approaching commercial availability. This project considers the development and application of this new technology to the case of ORE integration using hydrogen.