Energy and the Environment-A Coastal Perspective

Tidal Current Energy

Tidal current energy is the result of harnessing the power of flowing water.  The gravitational interactions between the earth, sun, and moon cause ocean tides; actually, the moon has 68% control while the sun has only 32% (Elghali, 2009).  Then, more currents are caused as water flows through “relative constrictions” like inlets (Bedard and others, 2010).  This is the moving water that most tidal current systems attempt to exploit.

 

Mathematically, the nameplate capacity (full potential of the system if it were always functioning at maximum output) is determined by the power density equation:

Power Output = ½ p A V³

 

where rho (p) is the density of the fluid, A is the cross-sectional area of the device, and v is the velocity of the fluid (Elghali, 2009).  Since water is around 800 times denser than air, slower moving water can generate much more energy than fast moving air, as proved by the power density equation.  In fact, the power output of water moving 12mph is the same as air moving 110mph over the same square area (“Home”). This huge energy source found in ocean currents and tides has incredible potential to provide coastal communities with constant, renewable energy.

 

Global Ocean Currents – Photo Courtesy of patrick1952.

 

References

Bedard, Roger, Paul T. Jacobson, Mirko Previsic, Walter Musial, and Robert Varley. “An Overview of Ocean Renewable Energy Technologies.” Www.tos.org/oceanography. The Oceanography Society, June 2010. Web.

 

Ben Elghali, S. E., M. E. H. Benbouzid, and J. F. Charpentier. “Marine Tidal Current Electric Power Generation Technology – A Review.” Electromotion 16.3 (2009): 155-168. Academic Search Complete. Web. 15 July 2012.

 

“Home.” OCS Alternative Energy and Alternate Use Programmatic EIS Information Center. OCS Alternative Energy and Alternate Use ProgrammaticEISInformationCenter, n.d. Web. 22 May 2010. <http://www.ocsenergy.anl.gov/>.

This page has the following sub pages.

• Tidal energy case studies
• How It Works
• Types of Devices
• Requirements for Turbine Location
• Present Installations
• Gulf Stream Potential

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