The European tidal industry is at a critical stage. Successful demonstration of small-scale tidal arrays with lessons learnt for future large-scale projects is widely acknowledged as a key way to de-risk and kick-start the tidal energy industry. The DEMOTIDE project will design, build and operate a 4 x 1.5MW (6MW) turbine array at the MeyGen Phase 1B site, Pentland Firth, Scotland. The potential for build-out on the MeyGen site to 400 MW installed capacity, based on the available local high flow tidal resource, make this a site ripe for commercial exploitation. The DEMOTIDE consortium unites strong players with each of the required competencies to deliver this array. Leading technology supplier Marine Current Turbines (an Atlantis company) can rely on experience gained from operating its SeaGen tidal turbine system for several years. The participation of both MCT and Atlantis technology development teams is crucial to deliver robust, efficient turbines, fully specified to perform in challenging tidal site conditions. Effective installation plans are only possible through early involvement of an experienced marine contractor. DEME, comprising DEME Blue Energy and GeoSea, is a world leader in marine operations and owns a versatile fleet (jack-up platforms, DP, heavy-lift, barges, etc.) which can be applied to the tidal market. DEME subsidiary GeoSea will bring extensive offshore wind energy installation experience to the table. The combined involvement of DEME Blue Energy, Atlantis Resources, and French partner INNOSEA provides a strong route to exploitation of the results of DEMOTIDE across a portfolio of commercial tidal energy projects throughout Europe and abroad. Finally, local content and dissemination of the project results is ensured through involvement of Queen’s University Belfast and local contractors in Scotland for onshore works.

This project investigates the effects of extreme conditions on marine energy generators when installed as a single device or in arrays or farms. By combining the results of experiments, computer predictions and real life expertise, the research will enable the industry to produce, design and manufacture better tidal stream turbines that can be optimised to suit the prevailing sea conditions. Once these devices are deployed there will be a need to remotely monitor their condition and manage their operation during their life time. This research will deliver a system that will allow the owners of the devices to remotely monitor their condition and performance to ensure they achieve optimal energy production whilst maximising their life span. This will enable the electricity suppliers using this source of renewable energy to achieve the best possible long term economic performance. Finally, the environmental impact of such installations will be considered to ensure the positioning of these devices is not detrimental to the surrounding sea, coast and seabed.

Any structure exposed to breaking waves, be it a simple breakwater or a complex and expensive marine energy machine, will be exposed to high wave impact loads as overturning wave crests slam into it. The violence of the motion of the water surface as waves break are well-known to surfers who seek out such conditions. Marine renewable energy devices will be hit by the most violent storms that nature can produce, yet they are required to produce significant power when the weather is benign and the waves relatively small. This dichotomy can result in expensive failures such as that of the Osprey, a 2MW wave power prototype device located off the north coast of Scotland, which was damaged and sank in a storm. If marine renewable energy is to play a significant role in meeting the energy requirements of the the United Kingdom, all energy extraction devices must survive for many years and many large storms without damage. Hence accurate design methods are required to estimate the peak hydrodynamic loads occurring in such storms. This project explores the science and engineering required to ensure that renewable energy devices survive extreme conditions, and seeks to identify the upper limit of device operations in less severe conditions. Key to making a significant advance in survivability is understanding how steep and violent waves behave on significant currents. Both wave power machines and marine current turbines are likely to be located in relatively shallow water with relatively fast tidal currents, obviously for tidal turbines this is a virtue! If the current is fast and the water shallow, there will be considerable resistance to the flow close to the sea-bed and less further up towards the surface. Thus, the current is likely to be highly sheared and very turbulent. Add on top of this bulk flow violently overturning steep waves and it is clear that the water will be moving around very fast in local regions. The first part of this project is to characterize the statistics of waves and how this varies over time for decades to decades. Next the waves are combined with sheared currents. Then models of marine renewable energy devices will be exposed to such violent combined wave and current events and the forces measured. Finally we aim to develop and test force computer based computational methods for assessing loads. The overall output from this research project will make an important contribution to removing blocks limiting and slowing down the large-scale implementation of marine renewable energy.

This work aims to provide industry with system to fill key knowledge gaps on the distribution of small cetaceans at tidal turbine sites assisting the timely and cost effective development of tidal powered renewable energy generation in an environmentally safe manner. If mankind is to control atmospheric carbon dioxide levels and manage climate change, and if the UK is to meet its legally binding carbon reduction targets, it will be essential to make full use of all appropriate technologies for renewable power generation. The UK is fortunate in having substantial potential for generating renewable power offshore. Tidal power has the unique advantage amongst renewables technologies of being completely predictable and is thus a particularly valuable component of any renewable energy portfolio. Tidal stream turbines are site in tidal rapid areas. These are rather small and unusual habitats which have comparatively little studied. One of the main environmental concerns with the use of tidal stream generators is that large animals such as marine mammals will be in collision with the rotating blades and suffer injury or even death. All cetaceans are European Protected Species. To assess collision risk we need to know the probability that animals will be in the vicinity of rotating turbine blades. This is a function of both the two dimensional spatial density distribution of animals and their distribution with depth. This information is currently lacking at all UK tidal rapid sites. This lack of knowledge introduces both environmental and economic risks. Planning consent applications are being delayed, onerous and costly mitigation measures may be placed on developers and development may initially be allowed only on a "deploy and monitor" basis which carries the risk for developers that devices may have to be removed if collisions do indeed occur. There are well developed methods to determine the two dimensional distribution and density of cetaceans. However, we believe the only practical technique to measure dive depth and underwater behaviour in these challenging habitats it so use drifting vertically oriented arrays of hydrophones to locate vocalising animals by time of arrival difference techniques. It was this conviction that led us to start working to develop such systems, and the software to analyse the data they produce, in 2009. Since then we've developed and thoroughly tested a system which is deployed from a drifting vessel. Field tests have shown that the system provides reliable and accurate locations and that animal vocalisation can be linked into tracks to reveal underwater movements and we are building a significant dataset of new information on porpoise underwater behaviour at putative tidal sites, mostly in Scotland. To be widely useful to industry however, the system needs to be sufficiently straight forward for industry and their consultants to deploy routinely. We've largely achieved this with the software by incorporating it into PAMGUARD, a feely available open sources cetacean detection, localisation and tracking package. However, the hardware is somewhat cumbersome, reflecting its origins as a research and development system. We are confident that recent technological developments provide several options for developing an affordable, self contained autonomous buoy-based system that can be hand deployed from a small boat e.g. a Rhib and the operate autonomously. This should be straight forward for non-specialist teams to utilise in the field and because a much smaller vessel is required field costs should be substantially reduced. We've also identified hydrophones as an area where we can provide knowledge to allow substantial cost savings. This proposal aims to take the knowledge and IP from the existing system and repackage it in a less expensive and more easily used buoy based system and make this, along with customised software, freely available as an open source resource.

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.