Tidal and marine energy in the uk– identifying the future challenges for supply chain development

The purpose of this paper is to investigate the current technical and operational supply chain issues surrounding the development of tidal and marine energy production in the UK. The paper outlines the market and growth potential of tidal energy production in the UK before identifying the key supply chain themes surrounding tidal energy production including an analysis of the portability and transferability of current supply chain thinking and development from other renewable energy systems such as wind turbine technology towards the development of tidal energy supply chain systems. The paper closes by identifying the major challenges that the UK supply chain must overcome in order to develop a comprehensive and robust supply chain system

The development of marine energy extraction

Accompanied with an increase in world population there is a growing demand for energy from both the industrial and domestic sectors [...

Performance assessment of a Horizontal Axis Tidal Turbine in a high velocity shear environment

The main focus of this thesis was to assess the performance of a full scale Horizontal Axis Tidal Turbine (HATT), using the CFD package, FluentrM, and measured high shear tidal profiles. Two sites are considered: the Anglesey Skerries and a site in the Severn Estuary, both off the Welsh coast. In order to achieve this aim a number of key steps were performed including the use of an existing laboratory scale prototype HATT to establishing the optimum blade pitch angle and provide an experimental data set. Once established the HATT CFD model was used to scale up from the laboratory scale to 30 m diameter. By the use of non-dimensionalised characteristics of power, thrust and torque coefficients, it was shown that the HATT was scaleable and independent of Reynolds number. Using these findings a suitable turbine diameter was determined for site specific analysis. Velocity profiles from the two sites were obtained via vessel mounted Acoustic Doppler Current Profiler (ADCP) surveys. These data were used to define a high velocity shear environment. When non-dimensionalised these data were found to also collapse onto the scaling curves provided a true average for the velocity, across the swept area, is used. In addition, when the HATT was 'positioned' at varying depths down the water column the power extraction was shown to reduce considerably with depth. When positioned close to the seabed, the cyclic torque, power and axial thrust loads were studied with and without a stanchion positioned downstream of the turbine. The presence of a stanchion was also shown to significantly increase the amplitude of the cyclic torque, power and axial thrust during rotation. The findings of this thesis suggest that the complexity of the dynamic torque, power and axial thrust, along with the wake profile, are influenced by the HATT's interaction with the ocean seabed. These complexities are therefore of prime importance when considering a deep water application which encompasses all or part of a high velocity shear regime. The work presented in the thesis shows that it is possible to predict a turbine's performance (for a given geometry) for any scale and velocity profile, from a single diameter. When positioned lower in the water column, the downstream wake also showed a high level of asymmetry which was also shown to influence the upstream flow field

Development of a wave-current numerical model using Stokes 2nd Order Theory

The optimisation of a method to numerically simulate 3D velocity fields of combined wave-current flows, at individual wave resolution, is proposed. ANSYS CFX 18.0 was used to develop a homogenous multiphase model using volume fractions to define the different phase regions. By applying CFX Expression Language at the inlet of the model, Stokes 2nd Order Theory was used to define the upstream wave and current characteristics. Horizontal and vertical velocity components, as well as the surface elevation of the numerical model were compared against theoretical and experimental wave data for 3 different wave characteristics in 2 different water depths. The comparison highlighted the numerical homogeneity between the theoretical and experimental data. Therefore, this study has shown that the modelling procedure used can accurately replicate experimental testing facility flow conditions, providing a potential substitute to experimental flume or tank testing