Device interactions in reducing the cost of tidal stream energy

• Numerical modelling is used to estimate the levelised cost of tidal stream energy.
• As a case study, a model of Lynmouth (UK) is implemented and successfully validated.
• The resolution of the model allows the demarcation of individual devices on the model grid.
• Device interactions reduce the available tidal resource and the cost increases significantly.

The levelised cost of energy takes into account the lifetime generated energy and the costs associated with a project. The objective of this work is to investigate the effects of device interactions on the energy output and, therefore, on the levelised cost of energy of a tidal stream project, by means of numerical modelling. For this purpose, a case study is considered: Lynmouth (North Devon, UK), an area in the Bristol Channel in which the first tidal stream turbine was installed − a testimony of its potential as a tidal energy site. A state-of-the-art hydrodynamics model is implemented on a high-resolution computational grid, which allows the demarcation of the individual devices. The modification to the energy output resulting from interaction between turbines within the tidal farm is thus resolved for each individual turbine. The results indicate that significant changes in the levelised cost of energy values, of up to £0.221 kW h−1, occur due to the aforementioned modifications, which should not be disregarded if the cost of tidal stream energy is to be minimised.