This post is the continuation of my previous blog on water power.  In that segment I summarized tidal and wave energy technology.  I had planned on discussing microhydroelectric installations, Vortex Hydro Energy, and ocean thermal energy conversion (OTEC) in this section, however because there is SO much important information I have decided to again separate the post into another part.  This piece will focus on microhydroelectric power and the Vortex Induced Vibrations Aquatic Clean Energy (VIVACE) system which both utilize flowing water to generate electricity.

Microhydroelectric Installations:

Microhydroelectric power is very similar to hydroelectric power but it is adaptable for small-scale installations such as single homes or small communities.  Microhydro generally only produces up to 100kW of power and is much more sustainable than big, traditional hydroelectric power installations.  And even more appealing is the fact that microhydro does not require rivers to be completely dammed.  This is very beneficial because dams interrupt the water cycle, travel of fish and animals, and the flow of nutrient rich sediment downstream.

Microhydroelectric power is generated using the energy from flowing water.  First an intake tank filters the water to ensure no debris or fish enter the system.  The water then flows through a pipe (called the penstock) to a controlling valve that regulates the flow and speed of a turbine.  The turbine turns a shaft that is used to power a generator, which converts the flow and pressure of the water to electricity!

This energy can then be stored in batteries and distributed to the power system.  At the end of the process, the water used in the system is returned to the river or stream along a tailrace channel.

The image below is from a PowerPoint presentation used in a course I took at the University of Vermont called “Sustainable Development of Small Island States: St. Lucia.”  I had the opportunity to see first hand how well the microhydro system worked for the owner of the land, Mr. Sly Joseph.  Mr. Joseph powered his whole home and an outdoor classroom using the power generated at the La Tille Waterfall on his property.  The local schools teach classes on his property to spread the message about how well microhydro power works, especially on small islands where traditional electricity is very expensive and not readily available.

Vortex-Induced-Vibration (VIV)/ Vortex Hydro Energy:

VIVACE (Vortex Induced Vibrations Aquatic Clean Energy) is an emerging technology that extracts energy from flowing water currents and utilizes the science of vortex-induced vibrations.  Most of the research I could find on the technology was quite confusing, primarily because the science explaining VIV is quite complex. However, using VIVACE technology is actually quite simple. http://www.vortexhydroenergy.com is a great site that explains the system very well.

VIVACE is the only water power technology that I will discuss that does not use any turbines, and because the cylinder oscillations are only about one cycle/second there is not direct threat to aquatic life passing through.

Boxes with cylinders are installed on a riverbed or suspended under the surface of the water, as the water flows through the cylinders the movement causes the cylinders to move up and down. The cylinder is attached to a magnet that also slides vertically, creating a DC current.  The DC current is then converted to AC current.

The phenomenon behind how the cylinders of the VIVACE system move perpendicular to the current direction is the same as how fish move through the water.  Very basically, vortices are produced and discarded on the downstream side of round objects in a fluid current.  The vortex shedding oscillates between the bottom and top of the object, thus creating an alternating lift on the body.

The company responsible for the design, Vortex Hydro Energy LLC, predicts that an array of cylinders about 2 stories high could power about 100,000 homes.  The technology can be used to power desalination plants, use energy from rivers without dams and provide power in coastal areas.

I love the microhydroelectric and VIVACE technologies.  Both are very simple systems that have small-scale potential (unlike wave, tidal and OTEC power which can only be installed for large-scale energy production).   Both systems can be installed on a small river and, without changing the site very much, can utilize the energy in flowing water to provide electricity for a home nearby or a community.   Hopefully these systems will be implemented more to reduce our dependence on fossil fuels and on traditional hydroelectric power which dramatically alters the environment.

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