The project will develop a proof-of-concept planning model for central planners to optimally locate electric vehicles (EVs) charging infrastructure under the risk of disruption to charging points (i.e. unexpected failure of charging points due to technical faults or breakdowns). The aim of the model will be to maximise total expected traffic volume of EVs that can be charged by an unreliable integrated charging network. Both static and dynamic wireless charging systems, as well as railway feeder stations will be considered. A robust mixed-integer non-linear programming (MINLP) model for this problem will be formulated. Queuing theory equations will be incorporated into the model to account for the stochastic nature of demand both spatially and over time (e.g. peak versus off-peak periods). The model will be further generalized to a multi-period planning problem given limited periodic budgets. The model will be linearized so that it can be solved using a general purpose solver. Finally, an efficient metaheuristic algorithm will be developed to solve the large-scale real-world instances within a reasonable computational time. A case study of the road network in the UK will be used to assess the accuracy and performance of the linearized optimization model and the metaheuristic algorithm. Besides the model and the algorithm, other project outputs will be the creation of test datasets and one or more journal articles. Codes of the model and algorithm, and test datasets will also be made available to the community of Operational Research so that other researchers and practitioners (e.g., National Grid) can use them in their own case studies.

The UK is committed to reducing its greenhouse gas emissions by at least 80% by 2050, relative to 1990 levels. Meeting this target will require a significant shift in the way energy is used (for example, through electrification of heat and transport) and generated. To reduce our dependency on fossil fuels, significant levels of Renewable Energy Sources (RESs) will need to be integrated into the power grid. RESs include energy sources that do not rely on fossil fuels and nuclear energy, such as solar, wind, tidal and wave. Some sources of renewable energy have been successfully incorporated (for example, pumped-hydro), and they are generally not classified as 'RESs' as this term refers to devices that are connected to the grid by means of power converters. While the benefits of RESs are undisputable and their installation should be facilitated, the integration of large amounts of these devices requires the development of new paradigms and methods to maintain a reliable and safe power system. RESs have certain characteristics that differentiate them from traditional sources: they are less controllable than traditional energy sources, they cause unintended power flow patterns, and they impact voltage and current waveforms and the overall power quality of electricity. This proposal will focus on the study of harmonic propagation in the UK power grid due to RESs. Harmonics are current and voltage components at frequencies multiple of the fundamental, and they are generated by the operation of the power converters. While low harmonic levels are tolerated and do not impact grid operation, increasing harmonic levels have detrimental effects including: increased losses, reduced efficiency, misoperation and reduced lifetime of equipment, and nuisance protection tripping. While the costs of harmonics are not easy to determine because of their long-term effect, it has become accepted by the power grid operators and users that increasing harmonic levels are detrimental for efficient grid operation. More importantly, they may compromise the future integration of RESs. This proposal aims at assessing the harmonic impact of RESs in the future power grid. Carrying out this assessment requires the development of accurate models of both RESs and of the power system. At the same time, these models requires some form of simplification because of the number of components involved. Previous research has focused on either detailed power converter models, or the use of a large power system model with simplified converter representation. This NIA aims at combining both aspects in a model which is able to represent correctly harmonic generation from RESs, the transfer of harmonics between voltage levels, and the representation of statistical variations of harmonic levels in the system, for varying levels of penetration of RESs. This research will involve close collaboration with two industrial partners, National Grid and Measurable Ltd, and with the University of Texas at Austin. The impact of this research will be widespread: the models developed will help the academic community in understanding the best approaches to study harmonic behaviour of large energy systems. This work will assist the system operator in assessing the impact of new RESs on the power system. Furthermore, this research will inform the future developments of power quality standards and of harmonic mitigating solutions. The ultimate goal of this project is to minimise the occurrence of harmonic problems in the future power grid, allowing for a smooth and clean integration of increasing amounts of RESs, not only in the UK, but on a global scale. Furthermore, it will benefit the UK as a whole in terms of maintaining the operations and efficiency of this ubiquitous infrastructure, whilst helping the government to meet targets for reducing CO2 emissions.

The UK is committed to reducing its greenhouse gas emissions by at least 80% by 2050, relative to 1990 levels. Meeting this target will require a significant shift in the way energy is used (for example, through electrification of heat and transport) and generated. To reduce our dependency on fossil fuels, significant levels of Renewable Energy Sources (RESs) will need to be integrated into the power grid. RESs include energy sources that do not rely on fossil fuels and nuclear energy, such as solar, wind, tidal and wave. Some sources of renewable energy have been successfully incorporated (for example, pumped-hydro), and they are generally not classified as 'RESs' as this term refers to devices that are connected to the grid by means of power converters. While the benefits of RESs are undisputable and their installation should be facilitated, the integration of large amounts of these devices requires the development of new paradigms and methods to maintain a reliable and safe power system. RESs have certain characteristics that differentiate them from traditional sources: they are less controllable than traditional energy sources, they cause unintended power flow patterns, and they impact voltage and current waveforms and the overall power quality of electricity. This proposal will focus on the study of harmonic propagation in the UK power grid due to RESs. Harmonics are current and voltage components at frequencies multiple of the fundamental, and they are generated by the operation of the power converters. While low harmonic levels are tolerated and do not impact grid operation, increasing harmonic levels have detrimental effects including: increased losses, reduced efficiency, misoperation and reduced lifetime of equipment, and nuisance protection tripping. While the costs of harmonics are not easy to determine because of their long-term effect, it has become accepted by the power grid operators and users that increasing harmonic levels are detrimental for efficient grid operation. More importantly, they may compromise the future integration of RESs. This proposal aims at assessing the harmonic impact of RESs in the future power grid. Carrying out this assessment requires the development of accurate models of both RESs and of the power system. At the same time, these models requires some form of simplification because of the number of components involved. Previous research has focused on either detailed power converter models, or the use of a large power system model with simplified converter representation. This NIA aims at combining both aspects in a model which is able to represent correctly harmonic generation from RESs, the transfer of harmonics between voltage levels, and the representation of statistical variations of harmonic levels in the system, for varying levels of penetration of RESs. This research will involve close collaboration with two industrial partners, National Grid and Measurable Ltd, and with the University of Texas at Austin. The impact of this research will be widespread: the models developed will help the academic community in understanding the best approaches to study harmonic behaviour of large energy systems. This work will assist the system operator in assessing the impact of new RESs on the power system. Furthermore, this research will inform the future developments of power quality standards and of harmonic mitigating solutions. The ultimate goal of this project is to minimise the occurrence of harmonic problems in the future power grid, allowing for a smooth and clean integration of increasing amounts of RESs, not only in the UK, but on a global scale. Furthermore, it will benefit the UK as a whole in terms of maintaining the operations and efficiency of this ubiquitous infrastructure, whilst helping the government to meet targets for reducing CO2 emissions.

The National Grid has identified periods of high electricity demand combined with low wind and sun as a key challenge for supply-demand balancing in Great Britain as it transitions to clean, but intermittent renewable power generation. This was evident in Autumn 2021, when a three week period of low wind coincided with a fourfold increase in imported wholesale gas prices, caused by high global gas demand. Consequently, over twenty energy suppliers ceased trading, and energy prices increased, leading to rising fuel poverty. Wind will remain the primary source of renewable power in the UK, but its intermittency means that similar 'wind-droughts' to that seen in 2021 will occur again in the future. Energy systems must be resilient to weather to address the 'trilemma' of generating clean, affordable, secure energy. This research investigates the roles of tidal stream, tidal range and wave energy in overcoming energy security challenges. Energy security is defined as 'the uninterrupted process of securing the amount of energy that is needed to sustain people's lives and daily activities while ensuring its affordability'. MOSAIC builds on recent research that has started to show how tidal stream, tidal range and wave power generation can lead to energy security benefits. Latest estimates indicate that the combined tidal stream, tidal range and wave energy resources around Great Britain can contribute 45% of the UK's current electricity demand. The timing of tidal stream/range power is independent of weather patterns, and instead depends on the positions of the sun, earth and moon, and the rotation of the earth. This characteristic of tidal power means that it can provide reliable electricity supply every day, and that the amount of tidal power generated at any time in the future can be predicted. Co-locating tidal stream and tidal range power plants can lead to a smoothing of the combined power supply, because the two technologies tend to generate power at different times of the tide. Wave power lags wind power to help provide a more stable overall renewable supply. The predictable, reliable, smoothed power generation provided by adopting tidal and wave energy enhances balancing between power supply and demand, reducing the need for costly imported power, energy storage and grid upgrades, for example. The aim of the research is to establish and optimise the contributions of tidal stream, tidal range and wave energy future energy systems to enhance energy security. This will be achieved by building new computer models that simulate the flow of power between components on the national and local electricity grids. The models will be able to optimise the amount of power provided by all generation technologies, including tidal and wave energy, in order to provide energy security. The project will deliver a roadmap that sets out the amount, locations and cost of new tidal/wave energy projects to deliver energy security enhancements between 2035-50. The roadmap will be informed by novel energy system modelling outputs at three different scales based on the energy systems of Great Britain, Wales and the Isle of Wight. The incorporation of three different scales allows the energy system models to simulate and optimise the transmission and distribution grids as well of power generation and energy storage. This novel approach is critical to fully understand the compatibility of different technologies. Results from the research will be communicated to UK Government, the National Grid and the Isle of Wight Council, to inform the design of future energy systems. The models will be freely available for anyone to use. This provides opportunities to establish the suitability of energy system models currently being used to design energy systems, which may over-simplify the simulation and optimisation of tidal stream/range and wave power.

Recent research suggests that the effects of climate change are already tangible, making the requirement for net zero more pressing than ever. Part of the solution for net zero will be geo-energy technologies in the North Sea, including offshore wind, blue and green hydrogen, and carbon capture and storage. These new technologies will interact with each other in the potentially-sensitive subsurface, seabed and water column. The project will assess the environmental sustainability of these technologies combined, for selected test areas of the UK offshore, and will develop solutions to make sure that the technology and infrastructure of the offshore energy transition, works well, is efficient, and does not harm the environment. Work package 1 focuses on the security and viability of industrial scale subsurface offshore hydrogen storage and carbon dioxide storage and investigates how the two might interact, and how best to make decisions about when to use storage space for hydrogen, and when for carbon dioxide. Work package 2 focuses on the characteristics of the sea bed and water column above the storage sites in the geology, and the effects of gas or fluid release from geological storage on the environment, and the environmental interactions of other offshore energy infrastructure like windfarms and cables. Work package 3 will focus on the social implications of an offshore energy transition, evaluating the risks and benefits of different technological scenarios to ecosystem services (the natural benefits that we get from the ocean, like fisheries), and it will look for net benefits where combinations of technologies provide extra environmental or efficiency improvements. Work package 4 will work with other WPs to ensure a fully integrated project, bringing together outputs from each work package into a usable form to support the decisions that stakeholders like the Oil and Gas Authority, Crown Estate, National Grid, and operators like Equinor, might make in the future.