The development of tidal stream energy presents a significant opportunity for the UK with a power generation potential in excess of 6GW nationally, and greater than 150GW globally. Delivering on net-zero and climate change objectives will require development and exploitation of all renewable energy resources to provide a robust and secure energy supply. The predictability of the tidal resource is a key benefit that can substantially contribute to resilient energy networks and complement less predictable renewable energy sources, e.g. wind, wave and solar. The UK currently leads tidal stream technology and science development, and there is significant opportunity to ensure global leadership of this exciting emerging sustainable energy sector. To date, the largest tidal device installed is 2MW and the largest array of devices is 6MW in Orkney and Pentland Firth respectively. Device technologies, marine infrastructure, deployment, and operational strategies have all been refined through industrial research, design and deployment at testing sites, assisted by university partnerships. The challenge now faced by the industry is to understand how to deliver tidal stream energy at a scale that will make a meaningful energy contribution. The solution hinges on the ability to deliver reliable, sustainable, scalable and affordable engineering solutions. The engineering challenge is complex and multi-faceted, and the importance of and sensitivity to design drivers are not always well understood. CoTide's research vision is to develop and demonstrate holistic integrated tools and design processes for tidal stream energy that will significantly reduce costs by removing unnecessary redundancy and improving confidence in engineering solutions, providing the transformative engineering processes and designs that will enable tidal energy to make a significant contribution to achieving climate change objectives by 2030-40. CoTide brings together three major university multi-disciplinary teams, each with deep world-leading expertise across the major engineering disciplines essential for the design of tidal stream devices. These include device hydrodynamics, composites and rotor materials, structures and reliability, metocean resource and environmental modelling, system control and optimisation. The constituent engineering design capabilities will be integrated towards addressing the big questions facing tidal stream energy developers through a unified control co-design process. Through this holistic approach, CoTide will not only develop the framework to assess the impact of design drivers and design decisions but will contribute fundamental understanding of unsteady rotor loads and means to control and resist these, how to use contemporary and emerging manufacturing methods to benefit cost and through-life reliability in addition to maximising the potential of digitalisation for optimal performance. With input from its Independent Advisory Board, the Programme resources will be periodically reviewed, adapted and refocused to concentrate on the research challenges that emerge from our research, the tidal energy sector and policy space, and that offer the best opportunities to support industry cost reduction pathways. As CoTide evolves, in addition to its core skills, the partners have a significant breadth of additional expertise to draw upon, with world leading capabilities in complementary areas within offshore renewable energy. CoTide is an ambitious but realistic programme that has the scale, academic gravitas, and resource to achieve innovation through addressing transformative design questions. Through its co-design framework, considering the full scope of interconnected engineering challenges and environmental factors, it will deliver the understanding, tools and data to support the progressive and step change reductions in cost and uncertainty needed to deliver scalable, sustainable and affordable tidal stream energy.

THE PROBLEM: Offshore windfarms will be developed at an accelerated schedule under fast-track plans to switch away from fossil fuels. With ever larger offshore windfarms, and the cumulative effects of climate change, we thus urgently need to understand the way the seabed is modified in response and how such changes affect the wider marine ecosystem. When natural currents in the sea deviate around the wind turbines or anchors, the forces acting on the bed enhance, making sediments move and stay in suspension. This reduces the clarity of the water and changes the shape and sediment composition of the seabed, with impacts stretching far beyond the object. The seabed supports ecosystems that deliver a wide range of services incl. fishing, carbon storage, aggregates and coastal protection. The climate crisis will stretch impacts even further and into coastal zones, as future storm waves and rising sea levels will alter the ways energy from the sea is transferred to the seabed. All these changes combined can have wide-reaching impacts for organisms that live on or in the seabed, potentially changing biodiversity (species richness) and the delivery of some of these ecosystem services. The impacts at the seabed extend through the food chain to the water column and beyond as seabed dwelling fish are consumed by seabirds and cetaceans. Aggregations of fish can be strongly associated to particular seabed properties. If displacement or mortality occurs amongst these important prey species, this has knock-on effects for the deep-diving predators that cannot afford to be less efficient in foraging for food, like the seabirds that are protected by legislation. During this pivotal time of energy transition and national security, it is of crucial importance to better understand and unlock the potential of the marine environment for a renewable energy transition with added benefits to the ecosystem. AIM: This proposal sets out a strategy to assess the seabed response to the combination of accelerated windfarm expansion and accelerated climate change, and to quantify the implications for (1) biodiversity, (2) ecosystem services, (3) habitats, and (4) interactions between seabird populations and their food. We ultimately seek to help identify opportunities that benefit the conservation of species and increase biodiversity around windfarms. We will help windfarm developers design their monitoring strategies long beyond the life-span of our project. SUMMARY OF METHODS AND OUTPUTS: Via a multi-proxy study using observations, laboratory experiments and models, we will assess and map, under different climate predictions, how the stresses on the bed will be modified by 2050, how the distribution of seabed habitats and biodiversity will change, and how that drives changes to ecosystem services and the foraging success of deep-diving seabirds. We will design relevant scenarios, where we consider offshore windfarm size, scour mitigation strategies, predator behaviour and the ecosystem's vulnerability to change due to the combined effect of accelerated windfarm expansion and climate change. We will use the Eastern Irish Sea area as case study, as it is the home of a variety of seabird species with specific predator-prey relationships, of diverse seabed types and of considerable windfarm expansion nearby existing windfarms. To help all developers of windfarms in the UK, UK-scale maps will be made of the vulnerability of the seabed to change, and a new seabird vulnerability index will be developed. Our quantification of how these processes from seabed to seabirds interact can directly inform/feed into existing and future decision support tools. We will provide a tool where stakeholders can run their own simulations anywhere around the UK and for any given model/data resolution to quantify uncertainty levels of bed stress caused by windfarms, with cascading effects of uncertainty in habitat and biodiversity distribution and ecosystem services.