Can tidal-stream turbines power the Blue Economy?

Abstract:

Marine renewable energy research and industry of hydrokinetic devices have predominantly focused on MegaWatt-scale horizontal axis tidal-stream turbine power, for electricity generation and reducing their associated cost (i.e. LCOE). The application of hydrokinetic energy devices to “higher value” energy markets (i.e. beyond electricity supply) has been suggested as a way to support the industry as it develops into a cost-effective solution to energy poverty. For example, there has been much interest in the integration of hydrokinetic energy devices with offshore aquaculture, or the powering of communication systems and desalination. Here we aim to understand if current understanding of devices, and research tools for mapping the resource, are suitable for smaller-scale hydrokinetic energy devices that may have much lower rated power but more reliable energy needs. A normalised tidal-stream turbine power curve, developed from published data on 17 devices, was developed. Our normalised, and therefore scalable, power curve was applied using a power-demand optimisation algorithm, and divergence in device characteristics was found in optimisation of yield or persistence of power. Furthermore, the optimal device characteristics for tidal-stream energy devices were mapped onto resource needs and the oceanographic conditions of other “Blue Growth Industries” such as offshore aquaculture. Initial results suggest a different resource considerations and device design concepts are needed to power industries associated with less energy needs and lesser energetic regions of the ocean.