Tidal Power

John Keller
December 15, 2016

Submitted as coursework for PH240, Stanford University, Fall 2016


Fig. 1: An example of a tidal turbine that has been mounted to the sea floor. (Source: Wikimedia Commons)

Due to recent advancements in the understanding of global warming and its detrimental nature, many people have become infatuated with renewable energy and its variety of forms specifically tidal power. Tidal energy takes advantage of the vast size of the ocean and its natural tides in order to harvest energy into tidal power. More specifically, the best places to take advantage of tidal power would be "the entrance to a bay , or in a channel between an off short island and the mainland" coincidentally these are places that usually need to be adjusted anyway, in order to allow the passage of large commercial ships. [1] In order to take advantage of the tidal power, one must install tidal turbines. The tidal turbines, as shown in Fig. 1, are simply driven by the power of the tides of the sea. More specifically, these "tidal current turbines extract the kinetic energy in moving water to generate electricity... [and the] turbines must be able to generate during both flood and ebb tides". [2] These turbines have quite simplistic makeups, they consist of "a number of blades mounted on a hub (together known as the rotor), a gearbox, and a generator". [2] The science behind the turbines is that the turbines use, "the hydrodynamic effect of the flowing water past the blades causes the rotor to rotate, thus turning the generator to which the rotor is connected via a gearbox. The gearbox is used to convert the rotational speed of the rotor shaft to the desired output speed of the generator shaft". [2] This process provides substantial amounts of clean energy. This energy can then be converted into electricity to provide power in order to fulfill mankind's everyday needs.

Tidal Power's Environmental Impact

Tidal power is quite, unique form of renewable energy. It is particularly exhilarating, especially when compared to wind and solar power because tides are always present, so energy would always be produced. Tidal power could be an extremely effective and environmentally friendly approach to providing renewable energy, however, it poses its challenges. "Water is 832 times more dense than air", so as a result, the tidal generators would need to be specifically designed to withstand the forces of the tides and strong enough to hold its own weight when there is no tide. [2] The value of the energy produced will need to overpower the cost of production combined with challenges and expenses of maintenance and installation, as the generators are in water. Overall, if an effective, low maintenance and durable form of tidal generators are engineered, tidal power will overtake the renewable energy industry due to its year round reliability and its overall efficiency.

© John Keller. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.


[1] C. Garrett and P. Cummins, "The Power Potential of Tidal Currents in Channels," Proc. R. Soc. A 461, 2563 (2005).

[2] F. O. Rourke, F. Boyle, and A. Reynolds, "Tidal Energy Update 2009," Appl. Ener. 87, 398 (2010).