| dc.description.abstract | Tidal power is a clear and constant renewable ocean energy that can be predicted
accurately. With the rapid development of shallow water turbine technologies in the
commercial market, the uncertainties of the investment in terms of cost-benefit assessment
can be reduced. The tidal current energy conversion is considered as one of the favorable
alternative in Taiwan’s energy policy. One of the crucial issues is the impacts that may be
brought by the installation of turbines. As the kinetic energy is uptaken, the follow field will
change and hence the transportation of nutrients, plankton and lava will altered, which leads
to the direct impact of ocean ecosystem.
The aim of present study is to setup a high-resolution 3-D ocean circulation model that
is capable to simulate the tidal current at curvy coastline in Peng-Hu Archipelago. The
numerical model system is first validated using field measured datasets. From the simulation
results, it is found that the Hou-Men Channel and western Si-Yu sea area have the greatest
energy potential in Peng-Hu. It is worthy to noted that the processes of tidal dynamic in the
inner-bay of Peng-Hu Archipelago behave similar to a lagoon with two narrow open ends,
where the effects of phase lags of major constituents is limited. The almost synchronized tidal
current flow into the inner-bay from the north and south ends can be identified during flood
tide and vice versa. Concerning to the approaches to simulate the effects of the installation of
tidal energy conversion units, this study adopted the method of modifying the bottom drag
coefficient to simulate the flow field change incurred by installing difference turbine of
various capacities.
Furthmore, the discussions on the change of current fields in the vicinity of installations
as well as the change of water body exchange rate in the inner-bay with respect to various
turbine capacities are carried out.
In the Hou-Men Channel case, the location of strong current stream will move northward due
to the installation of turbines, and the velocity increases in the south channel. In western
Si-Yu sea area, the location of strong current stream moves westward. From the results, both
Hou-Men Channel and western Si-Yu sea area entertained more severe impacts of the shifting
of strong stream locations as the capacity of turbine increased.
This study also compares the variation of the rates of water body exchanged at different
sites through the tracer simulated experiments. For example, the setup a 30kW idealized
turbine in Hou-Men Channel will inccur, the tracer spearding area reduced by 16% compared
to original case. In western Si-Yu sea area, there seems no significant altering of tracer
spreading with respect to different capcities of turbine.
| en_US |