Economic Assessment of Tidal Hydrokinetic Turbines Under Different Energy System Configurations

This article proposes a methodology to estimate the cost of electricity in energy systems where tidal hydrokinetic turbines (HKT) are used to harness tidal power. This cost is assessed for three different energy systems: (i) an off-grid island (i.e., without the possibility of consuming electricity from the mainland grid) where a local electricity demands need to be served from local renewable energy sources (HKT and other renewable energy sources), (ii) an on-grid industry interested in minimising its overall electricity bill by valorising renewable energy sources (HKT and other renewable energy sources), (iii) an electricity producer interested in maximising profit using HKT and selling electricity on the day-ahead market. In each of the three systems, battery storage may be installed. In our studies, investments in the different energy systems are optimised to minimise annual costs. The optimisation procedure relies on a linear program formulation. The optimisation results allow us to identify not only the costs but also the optimal capacity to install, as well as the best operational strategies regarding the time series used for the optimisation. Those are generated for different WACCs (Weighted Average Cost of Capital) and discussed. Our results show that there is a financial interest in investing in HKT when an electricity demand has to be served locally (energy systems (i) and (ii)). However, using this technology only for selling electricity to the wholesale market is not yet profitable (energy system (iii)).