The ever increasing demand for electricity consumption accompanied by environmental pressures impose a continuing need for electrical systems modification and growth, partly because of changing operational practices resulting from de-regulation and, partly, due to the increased use of distributed generation, which is changing the demands on transmission and, especially, distribution lines. But for many years now, the opportunities for installation of new lines have become very limited because of public concern over visual and other environmental impacts, and it is clear that extensions to system capacity will have to be met substantially without new lines.The voltage rating and the insulation coordination of transmission and distribution lines is determined by a combined consideration of the voltage stress applied to the line and its electrical strength. The stress arises from overvoltages due to switching transients or lightning surges. The magnitude of the switching overvoltage is controlled by the characteristics of the system components, and is more critical at the highest operating voltages. Lightning overvoltages, on the other hand, are of much larger magnitudes and are more onerous to distribution systems.IEC 60071 makes recommendations for the gaps and clearances to be used for specific voltage levels, and individual operators will then adopt safety factors above and beyond these recommendations, depending upon local conditions. Pollution, for instance, may reduce the breakdown voltage by up to 50%. These adopted clearances are usually very generous and can be optimised using modern equipment and practice.The investigators have researched for many years the possibilities for compact lines and substations through improved co-ordination of insulation and the use of polymeric insulators and more effective protective devices such as ZnO surge arresters. This programme, therefore, proposes to apply the compact line concepts to the up-rating of existing lines. It will involve statistical studies of switching and lightning surges that account for various parameters which affect the overvoltage magnitudes, such as closing times for circuit breakers and analysis of the possible state of the line in order to minimize the risk of re-closing onto trapped charge. The statistical variations of stress and strength of the system will be combined in a voltage-frequency plot to determine the risk of failure, which has to be minimized within economic constraints. The stress will be presented as the probability of a certain overvoltage occurring, and its distribution along a line will be controlled by the judicious placement of modern ZnO surge arresters. Electrical strength, on the other hand, can be presented as a probabilistic breakdown curve. It will be primarily derived from consideration of the breakdown curves taking into account the critical clearances at the tower and along the line. These principles have been studied over the years, but present-day pressures are causing a re-evaluation of the conventional limits and methodology. This is also supported by the excellent performance of modern ZnO surge arresters in controlling overvoltages and the superior pollution performance of new polymeric insulators. The programme will also include laboratory and field experimental programmes to test and characterise the new devices and configurations to be used for the compact design of the uprated lines. The main output of the programme is to establish well researched fundamental principles that will allow an efficient and safe design for the future transmission and distribution lines.The basis of this programme has been proposed by HIVES, Cardiff University and then moderated by discussions with an industry group involving National Grid, four UK DNOs, ESB and three line construction companies, whose views are embedded in the proposed programme.

By 2050 it's estimated >400 GW of energy will be gathered by offshore wind across the whole North Sea. For scale, Hinkley Point C nuclear reactor is projected to produce 3.2 GW. How will this increased anthropogenic use of our coastal seas impact already stressed marine ecosystems? And how will that same production of renewable energy offset risks of extreme climate change that, left unchecked, will increase the risk of biodiversity declines. There are many complex changes to ecosystems linked to Offshore Wind Farms (OWFs) that we need to understand now, so that the extent of increasing wind energy extraction further offshore is managed in the most sustainable way. An important effect of large wind energy extraction will be to reduce the amount of energy that would normally go into local ocean currents via surface stress, altering sea state and mixing. Conversely, there will be local increases in turbulence around turbine structures and seabed scouring near fixed foundations. Any change in ocean mixing may change the timing, distribution and diversity of phytoplankton primary production, the base of the food chain for marine ecosystems, to some degree. This has knock-on-effects on the diversity, health and locations of pelagic fish that are critical prey species of commercial fish, seabirds and marine mammals. Observed changes caused by operational OWFs in the southern North Sea include local surface temperature rise and the displacement of seabirds and fishing fleets from the OWF footprint, whereas seals often appear to be feeding near turbines. All of these changes have a linked component - important prey fish species - which are likely to aggregate near structures (as seen at other offshore platforms). Seabirds and fishing fleets subsequently have less space to hunt, with potentially increased competition for fish. However, if OWFs are also de facto marine protected areas and so positively affect local primary production, they may provide good habitat for fish population growth. So, what are the cumulative effects of current OWF developments and the thousands of additional planned structures? Do the physical, biogeochemical and ecosystem changes exacerbate or mitigate those resulting from climate change? As OWFs migrate further offshore as floating structures, how can current knowledge based on shallow, coastal fixed turbines be suitably extrapolated to understand the impacts on ecosystems dependent on seasonal cycles that are typical of deeper waters? PELAgIO will address all of these questions through an interdisciplinary, multi-scale observation and modelling framework that spans physical mixing through to plankton production, on to the response of fish and whole ecosystems. We will collect fine-scale data using the latest multi-instrumented acoustic platforms set beside and away from OWFs, complemented by autonomous surface and submarine robots to capture continuous and coincident data from physics to fish, over multiple scales and seasons to fully understand what is 'different' inside an OWF and how big its footprint is. These new data will test the effects on seabirds and marine mammals to build an OWF ecosystem parameterization that accounts for changes to mixing and wind deficit impacts, and is scalable to next-generation OWFs. This bottom-up, comprehensive approach will enable true calibration and validation of 3D ocean-biogeochemical-sediment modelling systems, from the scale of turbine foundations up to the regional and even cross-shelf scales. Identified changes will be integrated into Bayesian ecosystem models that enable the cumulative effects of ecological, social and economic trade-offs of different policy approaches for OWFs to be quantifiably assessed for present day conditions, during extreme events and under climate change.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

Chalk is a highly variable soft rock that covers much of Northern Europe and is widespread under the North and Baltic Seas. It poses significant problems for the designers of large foundations for port, bridge and offshore wind turbine structures that have to sustain severe environmental loading over their many decades in service. Particular difficulties are faced when employing large driven steel piles to secure the structures in place. While driven pile foundation solutions have many potential advantages, chalk is highly sensitive to pile driving and to service loading conditions, such as the repeated cyclic buffeting applied to bridge, harbour and offshore structures by storm winds and wave impacts. Current guidance regarding how to allow for difficult pile driving conditions or predict the piles' vertical and lateral response to loads is notoriously unreliable in chalk. There is also no current industrial guidance regarding the potentially positive effects of time (after driving) on pile behaviour or the generally negative impact of the cyclic loading that the structures and their piled foundations will inevitably experience. These shortfalls in knowledge are introducing great uncertainty into the assessment and design of a range of projects around the UK and Northern Europe. Particularly affected are a series of planned and existing major offshore wind farm developments. The uncertainty regarding foundation design and performance poses a threat to the economic and safe harnessing of vital renewable, low carbon, offshore energy supplies. Better design guidelines will reduce offshore wind energy costs and also help harbour and transport projects to progress and function effectively, so delivering additional benefits to both individual consumers and UK Industry. The research proposed will generate new driven pile design guidance for chalk sites through a comprehensive programme of high quality field tests, involving multiple loading scenarios, on 21 specially instrumented driven tubular steel test piles, at an onshore test site in Kent. This will form a benchmark set of results that will be complemented by comprehensive advanced drilling, sampling, in-situ testing and laboratory experiments, supported by rigorous analysis and close analysis of other case history data. The key aim is to develop design procedures that overcome, for chalk, the current shortfalls in knowledge regarding pile driving, ageing, static and cyclic response under axial and lateral loading. The main deliverable will be new guidelines for practical design that will be suitable for both onshore and offshore applications.

This project will undertake the research necessary for the remote inspection and asset management of offshore wind farms and their connection to shore. This industry has the potential to be worth £2billion annually by 2025 in the UK alone according to studies for the Crown Estate. At present most Operation and Maintenance (O&M) is still undertaken manually onsite. Remote monitoring through advanced sensing, robotics, data-mining and physics-of-failure models therefore has significant potential to improve safety and reduce costs. Typically 80-90% of the cost of offshore O&M according to the Crown Estate is a function of accessibility during inspection - the need to get engineers and technicians to remote sites to evaluate a problem and decide what remedial action to undertake. Minimising the need for human intervention offshore is a key route to maximising the potential, and minimising the cost, for offshore low-carbon generation. This will also ensure potential problems are picked up early, when the intervention required is minimal, before major damage has occurred and when maintenance can be scheduled during a good weather window. As the Crown Estate has identified: "There is an increased focus on design for reliability and maintenance in the industry in general, but the reality is that there is a still a long way to go. Wind turbine, foundation and electrical elements of the project infrastructure would all benefit from innovative solutions which can demonstrably reduce O&M spending and downtime". Recent, more detailed, academic studies support this position. The wind farm is however an extremely complicated system-of-systems consisting of the wind turbines, the collection array and the connection to shore. This consists of electrical, mechanical, thermal and materials engineering systems and their complex interactions. Data needs to be extracted from each of these, assessed as to its significance and combined in models that give meaningful diagnostic and prognostic information. This needs to be achieved without overwhelming the user. Unfortunately, appropriate multi-physics sensing schemes and reliability models are a complex and developing field, and the required knowledge base is presently scattered across a variety of different UK universities and subject specialisms. This project will bring together and consolidate theoretical underpinning research from a variety of disparate prior research work, in different subject areas and at different universities. Advanced robotic monitoring and advanced sensing techniques will be integrated into diagnostic and prognostic schemes which will allow improved information to be streamed into multi-physics operational models for offshore windfarms. Life-time, reliability and physics of failure models will be adapted to provide a holistic view of wind-farms system health and include these new automated information flows. While aspects of the techniques required in this offshore application have been previously used in other fields, they are innovative for the complex problems and harsh environment in this offshore system-of-systems. 'Marinising' these methods is a substantial challenge in itself. The investigation of an integrated monitoring platform and the reformulation of models and techniques to allow synergistic use of data flow in an effective and efficient diagnostic and prognostic model is ambitious and would allow a major step change over present practice.