The Next Clean Energy Source: Hydrokinetic Power

Tuesday, December 1st, 2009

Hydrokinetic power[1] is the power generated by capturing the energy from natural flowing water, such as tides, currents, and waves. It is similar to conventional hydroelectric power, or hydrostatic power[2], in that it harnesses energy from moving water to create electricity. However, unlike dams, hydrokinetic power devices do not disturb the natural flow of water with manmade barricading structures, thus have a minimal impact on the surrounding environment.

 

Hydrokinetic power is an emerging and promising clean energy resource with great potential for untapped power generation from oceans and rivers around the world. Although it is still largely unexploited and unknown, this source of renewable energy is getting increased attention since it does not emit greenhouse gases, it is capable of providing continuous power, unlike wind and solar sources, and it can be placed into flowing water with minimal infrastructure or impacts on wildlife and water quality. However, the design and research of hydrokinetic devices are still not as evolved as other renewable energy technologies; thus standard designs and best practices remain under development. To date, fully permitted pilot projects have already been deployed on-site.

 

Hydrokinetic conversion devices generate power by using submerged or partially submerged turbines. These devices are generally categorized as either rotating devices or wave energy converters. Rotating devices are deployed within a stream or current, thus capturing the energy from the flow of water across or through the turbine. This energy powers a generator without impounding or diverting the flow. Rotating devices work similarly to wind energy conversion devices, thus are commonly referred as underwater mills. On the other hand, wave energy converters create a system of reacting forces in which two or more bodies move relative to each other. One of these bodies, the displacer, is acted on by the waves. The second body, the reactor moves in response to the displacer.

 

According to estimates, the amount of energy that could feasibly be captured from U.S. waves, tides and river currents is enough to power over 67 million homes.

 

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[1] Hydrokinetic energy refers to the kinetic energy possessed by a body of water because of its motion.

[2] Hydrostatic energy is the potential energy possessed by a body of water because of its position or elevation above a reference or datum, commonly referred as “head”.