Modeling River Hydrokinetic Turbine Arrays to Optimize Energy Extraction

Natural Resources Canada (NRCan), under the Energy Innovation Program, is undertaking Research and Development (R&D) activities that aim to develop guidelines for river hydrokinetic energy (RHE) turbines array configurations and energy extraction optimization.

Deploying multiple turbines in an array is a natural choice for RHE developers to achieve the economy of scale and a good business return. In order to evaluate the performance of each individual turbine in the turbine arrays as well as to optimize power generation from turbine arrays, there is a need to understand the turbine’s configuration, spacing, as well as turbine-river interactions. Presently very limited work has been done in this area due to the infancy of the RHE sector and the technical challenges related to the complex flow features between turbines and rivers.

Numerical method is an effective approach to study large scale turbine arrays. However, simulating multiple turbines with detailed modeling of the full turbine’s geometry presents an enormous technical challenge in terms of computing resource and time required. Therefore simplified turbine arrays modeling tools that only require affordable computing resource becomes critical.

Mavi Innovations Inc., University Laval, Lambda2 and NRC carried out a turbine arrays study in 2015-2016. The study was funded as part of Marine Renewables Canada EcoEII project. The study identified simplified modeling methods (Effective Turbine Model) for simulating RHE turbine arrays. Overall, the simplified models match the simulation results with full turbine geometry. However, further improvements on the robustness and the accuracy of the models still need to be implemented. More research is also required to further develop simplified turbine models that can replicate other phenomena for turbine array configuration and spacing, such as the wake behind the turbines. In addition, as the model developed is based on the cross-flow type of turbines, there is a need to develop a simplified model for the horizontal axial-flow type of turbines as well. Once a modeling methodology is in place for both turbine types, the simplified models could become an effective tool for studying power generation of multiple rows of turbines deployed along a stretch of river. The present contract is to address this modeling gap.