| Scarcity of traditional energy sources lets the eyes all over the world turn to new energy. There has been considerable interest in recent years in the exploitation of tidal currents in coastal areas to generate electricity. These is an abundant tidal current energy along the sea shore of China. According to the statistical result about 130 water channel in the coastal area of China, the power potential of tidal current energy is as large as 1.4 million KW. Among those areas, Yangtze Estuary-Hangzhou Bay takes more than 50 percent of the total energy. This indicates the scientific and engineering significance in the study of tidal current energy in Yangtze Estuary-Hangzhou Bay.However, the study about tidal current energy in China is new, which leads to the lack of deep understanding in this field.In order to get further understanding about tidal current energy in China, a new method of estimating the tidal current energy is proposed based on theoretical derivation. Further more, this method is also applied to estimate the tidal current energy Yangtze Estuary-Hangzhou Bay.This study is divided into 4 parts:(1) The overview and comparison of the different methods for investigating tidal current re-sources are done based on the existing studies. Then a simple model is proposed based upon the assumption that a flat bottomed, constant width, channel in which the flow is driven by a head difference between the inlet and outlet. This model is used to indicate that there is a maximum rate at which energy can be artificially extracted from the flowing water and that this rate is related to the kinetic energy flux in the unexploited channel but with a extractable coefficient which is related to the channel terrain factors.(2)A high resolution model with unstructured 3D grid system FVCOM (finite volume coastal ocean model) has been applied to simulate tidal motion in the Yangtze Estuary-Hangzhou Bay. The numerical results of the refined model has been validated with the field observation results in 2009. The error between numerical and observation results in tidal stage is less than 10 cm; the maximum error of tidal current velocity is less than 15%. The numerical results show a good agreement with experimental results in hydrodynamics. Based on the numerical results, the analysis to the tidal current in Yangtze Estuary-Hangzhou Bay is further done.(3)Analysis the features of the tidal trend in Yangtze Estuary and Hangzhou Bay area,the place with large reserves of tidal current energy located in Zhoushan Islands and North Port of Yangtze river estuary. Tidal energy resources are usually concentrated in narrow channels, which are abundant in Yangtze Estuary-Hangzhou Bay.(4) Based on the mathematical expressions about tidal current energy resource reserves and theoretical maximum extraction rate and with the consideration of technological and economic factors, the tidal current energy resources exploitation amount is calculated.The numerical results show that:in Zhoushan-Daishan Tidal Channel, the theoretical power potential is 955.26 MW, the maximum extractable coefficient is 17.59%; in Zhenhai-Zhoushan Tidal Channel, the theoretical power potential is 1164.23 MW, the maximum extractable coef-ficient is 19.56%; in Daishan-Qushan Tidal Channel, the theoretical power potential is 429.15 MW, the maximum extractable coefficient is 20.33%; in Qushan-Shengsi Tidal Channel, the the-oretical power potential is 725..22 MW, the maximum extractable coefficient is 17.96%; in North Chongming Island Tidal Channel, the theoretical power potential is 238.90 MW, the maximum extractable coefficient is 18.43%。... |
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