Tidal Farms: Optimising site-specific layouts by combining analytical methods and fluid dynamic simulations

Tidal energy is a promising source of renewable energy that countries should consider including in their energy mix. This paper presents a simple and efficient methodology for the analysis of tidal farms. Specifically, we have used a Mixed Integer Quadratic Programming (MIQP) model to optimise the farm layout using a discrete approach. The farm is made up of HATTs (Horizontal Axis Tidal Turbines). We compare the results obtained with a conventional discretisation based on literature assumptions to a site-specific adapted discretisation. The latter is obtained through 3D fluid dynamic simulations performed in series using the SHYFEM software, which is based on the Shallow Water equations. SHYFEM is an open-source marine circulation code and has been equipped with turbines parameterized by momentum source terms: this allows to reduce the computational effort while maintaining the accuracy of the turbine behaviour predictions thanks to the Blade-Element\Momentum (BEM) approach. In addition, the BEM approach allows interactions between devices to be captured, making the code well suited for farm applications. The results show a +6.7% increase in power production achieved by using the site-adapted discretisation for the optimisation process.