Tidal range electricity generation into the 22nd century

Tidal range electricity generation schemes are designed to have a minimum operational life of at least 120 years, making it important to plan for changes such as Sea Level Rise (SLR). Previous studies have shown that schemes can maintain the existing tidal range within the impoundment and protect areas from flooding. Here it is demonstrated that tidal range technology can maintain the current tidal extent despite SLR and suggests the operational strategies to achieve it. The approach is the only way to safeguard existing intertidal habitats. Mechanical and electrical plant requires a major overall, upgrade or replacement every 40 years; the levelised cost of energy (LCOE) is structured in 40year periods reducing after the first period. Increasing the capacity or efficiency of the plant during the refits allows the protection of low-lying areas to be maintained and more electricity to be generated. The strategy requires energy to be used in pumping to achieve the current low tidal limits and the incoming tide to be curtailed to maintain the high tide extent, but there is very little effect on annual electricity production (AEP). Flexible operation can offer some protection from riverine flooding and existing inundation cycles can be maintained. Highlights • Changes to tidal range electricity generation with increasing sea level. • Ability to protect intertidal areas and habitats by maintaining existing tide limits. • Two-way tidal range generation with pumping to existing low tide limits

Hydrodynamic studies of floating structures: Comparison of wave-structure interaction modelling

Current panel methods for wave-structure interactions employ the potential flow theory, which provide fast, reliable and relatively accurate predictions for the marine structures, and now some open source packages, NEMOH and HAMS, are available. In this research, the relative utility and performance of NEMOH and HAMS is compared with the well-known, state-of-art software, WAMIT. To bring focus to these comparisons, this research is based on three different floating structures: the truncated cylinder; the truncated cylinder with heave plate; and a novel multi-axis TALOS wave energy converter. To make the comparison more useful, this research investigates the incomplete and overlapped panels for the simple cylinder, to examine whether the respective code can handle these and still provide a meaningful solution. The comparisons may help us to understand whether the incomplete and/or overlapped panels can be used for simplifying the numerical modelling of those very complicated marine structures. From the comparisons, it can be seen the open source software, NEMOH and HAMS, both could produce very good results for the simple single marine structure, but also exhibit different capacities in dealing with more complicated marine structures. Specifically, HAMS could handle the thin structures and the overlapped panels effectively as WAMIT

Numerical hydrodynamic modelling of a pitching wave energy converter

Two computational methodologies – computational fluid dynamics (CFD) and the numerical modelling using linear potential theory based boundary element method (BEM) are compared against experimental measurements of the motion response of a pitching wave energy converter. CFD is considered as relatively rigorous approach offering non-linear incorporation of viscous and vortex phenomenon and capturing of the flow turbulence to some extent, whereas numerical approach of the BEM relies upon the linear frequency domain hydrodynamic calculations that can be further used for the time-domain analysis offering robust preliminary design analysis. This paper reports results from both approaches and concludes upon the comparison of numerical and experimental findings

Numerical hydrodynamic modelling of a pitching wave energy converter

Two computational methodologies – computational fluid dynamics (CFD) and the numerical modelling using linear potential theory based boundary element method (BEM) are compared against experimental measurements of the motion response of a pitching wave energy converter. CFD is considered as relatively rigorous approach offering non-linear incorporation of viscous and vortex phenomenon and capturing of the flow turbulence to some extent, whereas numerical approach of the BEM relies upon the linear frequency domain hydrodynamic calculations that can be further used for the time-domain analysis offering robust preliminary design analysis. This paper reports results from both approaches and concludes upon the comparison of numerical and experimental findings

Numerical hydrodynamic modelling of a pitching wave energy converter

Two computational methodologies – computational fluid dynamics (CFD) and the numerical modelling using linear potential theory based boundary element method (BEM) are compared against experimental measurements of the motion response of a pitching wave energy converter. CFD is considered as relatively rigorous approach offering nonlinear incorporation of viscous and vortex phenomenon and capturing of the flow turbulence to some extent, whereas numerical approach of the BEM relies upon the linear frequency domain hydrodynamic calculations that can be further used for the time-domain analysis offering robust preliminary design analysis. This paper reports results from both approaches and concludes upon the comparison of numerical and experimental findings

Investigation of barriers against the development of hydro power schemes in Northwest England

This paper describes the development of a sequential decision support system to promote hydroelectric power in North-West England. The system, composed of a series of integrated models, addresses barriers to the installation of hydroelectric power schemes. Information is linked through an economic assessment which identifies different turbine options, assesses their suitability for location and demand; and combines the different types of information in a way that supports decision making. The system is structured into five components: the hydrological resource is modelled using Low Flows software, the turbine options are identified from hydrological, environmental and demand requirements; and the consequences of different solutions will be fed into other components so that the environmental impacts and public acceptability can be assessed and valued

A Frequency-Response Design Method for the Control of Wave Energy Converters in Irregular Seas.

In this paper we present a method of controlling wave energy converters (WECs) in irregular seas. The method controls the WEC so that its displacement frequency response achieves a predetermined characteristics, which is chosen to enhance performance. The design of the controller described is based upon a feedback structure, through deriving the control force from the required displacement of the WEC, rather than the actual displacement. The control setpoint (the required displacement) is synthesized from the incident wave, so prediction of the incoming waves is required, in common with other methods of control in irregular seas. The method is demonstrated using a linear time-domain model of a heaving cylinder. The control signal is generated using both impulse-response functions and transfer functions in order to compare the performance of each, in terms of control signal accuracy and power output, under conditions of reduced wave prediction time. The characteristics of the control force demand and power flow in the controlled system, and the effect on performance of errors both in synthesizing and predicting the incoming wave are investigated. The application of the controller design to a model incorporating non-linearity is also considere