The Analysis Of Tidal Energy In Zhoushan Island Based On FVCOM

Tidal energy is renewable. The utilization of tidal energy has important significance for themaintenance of human society, sustainable development, improvement of the global ecologicalenvironment and solving the problem of energy shortage. The first step of the utilization of tidalenergy is assessment of tidal energy at particular sites. The traditional methods such as Flux andFarm are usually based on the energy flux of the tide, and don’t consider the limitation from othercharacter of tidal energy. Further more the traditional methods ignore the effect from the tidalenergy turbine to the hydrodynamic environment, which will lead to overestimate the theoreticalavailable energy. Though the existing assessment methods, which are based on the numericalmodels, have considered the effect that mentioned above, they still cannot characterize the tidalturbine detail，or analyze the specific case of the utilization of tidal energy.According to the above background, in this study, a set of numerical simulations for the tide andtidal current has been established to improve the assessment of tidal energy. The study areasinclude the Changjiang estuary, Hangzhou Bay and Zhoushan Island. The numerical experimentsare based on the Unstructed Gid Finite Volume Coastal Ocean Model (FVCOM), which adopts anunstructured, variable resolution triangular grid system. The model was verified by the data from3tidal gauge stations and5ADCP stations. The result showed that the model could well simulatethe characteristics of simulated area. By analyzing the modeling results, the dissertation calculatedthe mean speed of tidal current, the probability distribution of the flow rate, the asymmetry of thetidal current, the principal axis of tidal current, tidal current energy reserves and so on.. Inconclusion, this dissertation assessed the tidal energy resource at Zhoushan Island based on theabove characteristics.In this dissertation, we also nested a smaller-scale2-dimensinal modeling to the above simulation.In the2D model, the water column is vertical averaged and a representation of turbine as bottomdrag is consistent with the physics of kinetic power extraction. The additional bottom drag isdetermined by the relationship between the dissipation energy from the bottom drag and the ratedrotor efficiency of the tidal turbine. Analyzing the effect from the tidal turbine to thehydrodynamic environment through the result from the modified numerical model, the result showthat: within5km, the effect to the elevation from the tidal turbine is less than10cm, the effect tothe tidal current speed is less than75cm/s and the effect to the current direction is less than15°.Considering the effect to the dynamic environment from the tidal turbine, theoretical availableenergy is10.312MW. In contrast, without considering the above effect the theoretical availableenergy is12.081MW.