Anti-biofouling strategy for operators: a systems approach for the tidal energy industry

Abstract

For a tidal energy operator, reducing costs and increasing reliability are paramount to delivering competitive renewable energy. This can be done in part by considering anti-biofouling solutions: the reduction, removal and recording of associated marine organisms which can impact numerous turbine operations, such as obstructing heat exchange or increasing blade drag, and can provoke environmental concerns. The aim of this thesis is to develop a comprehensive, quick and cost effective anti-biofouling approach for renewable energy operators, in collaboration with the tidal turbine developer Nova Innovation. Novel methodologies are needed for the operator to compare antifouling coatings, investigate biofouling removal intervals and record biofouling for engineering purposes and in relation to the potential presence of alien invasive species. A three stage anti-biofouling strategy for non-scientific turbine operators has been developed and tested in the high-flow environment of Shetland. Firstly, three frames were designed to enable four field experiments for the comparison of antifouling solution settlement panels. Secondly, basic image analysis was applied to underwater camera thumbnails to investigate biofouling amount and the preferred turbine cleaning season. Thirdly, 3D photogrammetry was employed for capturing and saving biofouling information from recovered turbines. The developed methodologies were found to be successful, resulting in a novel and practical anti-biofouling approach for renewable energy operators. Specific outcomes include (1) preferred coatings for turbines off Shetland: a silicone coating was the preferred blade coating and a copper coating was the preferred coating for the heat exchanger, (2) an estimation of turbine fouling in the Shetland location (given the current coating) resulting in a cleaning schedule suggestion of once every 1.5 years, (3) a 3D turbine model of millimetre accuracy for alien invasive species analysis, and (4) an observation regarding turbine heat distribution, suggesting that in particular warmer areas increase the amount of biofouling on turbines. In renewable energy, the conversation about biofouling reduction, removal and recording processes has only just begun. The tasks of linking theoretical results back to true turbine fouling, steps towards automating biofouling image analyses and integrating the approach into the company workflow are presented as future work.