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Tidal Streams: A Renewable Energy Source

Tidal streams, which are high velocity sea currents created by periodic horizontal movement of the tides, are often magnified by local topographical features such as headlands, inlets to inland lagoons, and straits. This movement creates large concentrations of kinetic energy. Despite the large tidal range on the Atlantic coast of Georgia, the state has not been considered as a location of significant tidal energy due to the relatively weak currents on the shallow depths of the continental shelf. However, this does not take into account the large currents that are generated inside the complex network of tidal rivers and creeks that make up the Georgia coast line. Coastal tidal stream currents can have significant spatial and temporal variability; therefore, predictions at one location are generally a poor indicator of conditions at another location.

Dr. Kevin Haas and researchers are presently applying a state‐of‐the‐art numerical model (ROMS) for simulating the tidal flows along the coast of Georgia. The coast of the State of Georgia is separated into smaller regions, each being simulated independently to determine tidal energy potential within that region. As an example, the simulation results for the Savannah River, Wassaw Sound and Ossabaw Sound are shown in a picture. Some of the rivers and channels e.g. the Savannah River, Wilmington River and Bull River have more tidal power than the others. In the case of the Ogeechee River within Ossabaw Sound and the Savannah River inlet, the results indicate concentrations of peak tidal stream energy ranging from 2 to 7 kW/m2. The potential power is found in terms of unit area, so the actual available power is found by multiplying this by the area of the flow. For example, a small channel 50 m wide and 5 m deep with 4 kW/m2 of potential power would actually contain a total of 1 MW of power.

Additional information about this research

Advanced equipment is used by researchers to measure currents in tidal streams off the coast of Savannah, Georgia.

 

 

 

Map showing the measured tidal power density in rivers and streams of Georgia's coast, near Savannah.

 

Dr. Kevin Haas and student document and analyze data collected from Georgia's coastal rivers and streams.