Archive for the 'Marine Renewable Energy' Category

Perpetual Ocean Visualization from NASA

This beautiful visualization from NASA shows ocean surface currents around the world during the period from June 2005 through December 2007.  Since most of the ocean’s surface currents are shaped by the wind, this visual can give us a sense of what the wind looks like over our oceans and can help students visualize why some places are better suited to utilizing offshore wind energy or wave energy than others.

Nature Inspired Wave and Tidal Energy Technologies

Australian based BioPower Systems BioStream technology generates electricity from tidal currents and was inspired by the Thunniform locomotion exhibited by shark and tuna species.

Their BioWave technology generates electricity from wave energy and was inspired by the motion of underwater plants (think kelp fronds!) that are anchored to the sea floor.  Read more about both technologies here.

Similarly inspired, Carnegie Wave Energy Limited’s CETO wave power converter produces high pressure seawater from the power of waves that can then power a turbine for electricity generation.

“The beauty of these wave-power technologies is that they move with the power of the ocean rather than putting themselves in confrontation with it.”-Ocean Energy Council

Guest Post: Whale Power by Daniel Arneman

Just how does a fifty foot long humpback whale dive deep and then leap from the water to the delight and amazement of whale watchers?  Certainly the whale is powerful, but there may be some other secrets to this 40 ton acrobat.

Scientist Dr. Frank E. Fish (yes – that’s his real name) went shopping for a gift one day, and spotted a humpback whale sculpture that seemed unusual.  On close examination, he discovered the sculptor had gotten the subject all wrong, carving bumps and ridges into the front of the whale’s fin.

Fish questioned the shopkeeper, explaining that accepted engineering standards require a smooth leading edge to cut through air or water.  The shopkeeper defended the sculptor, a meticulous whale watcher, and assured Dr. Fish that the humpback does indeed have bumps on the leading edge of its fins.

Perplexed, Fish investigated further and found that those bumps, or “tubercles,” have a dramatic impact on how the fin cuts through water.  It may not be a mistake after all!

Think back for a moment to a childhood car trip, waving your hand and arm out the window to feel the air rush by.  You noticed that if you held your hand out flat, then angled it up slightly, you could feel the lift of the air pushing against the bottom of your hand.  Make the angle too steep, and your hand would “stall,” being pushed backwards instead of up.

That “stall angle” is extremely important in the field of fluid dynamics, and it must be important to the humpback whale, because over time, its fins evolved a series of tubercles that actually increase the stall angle.  Put another way, the tubercles allow the whale to cut more sharply into the water, while still maintaining its forward momentum.  No wonder they can leap above the surface!

What does all of this whale talk have to do with renewable energy?  Well, a lot actually.

A company called Whale Power has created a wind turbine with “tubercle technology” built into the leading edge of the blades.  Just like humpback whale’s fins, the blades have a steeper stall angle and better aerodynamics, allowing them to harness more wind energy than their smooth competitors.  They produce more power, can operate at lower wind speeds, and are quieter than other turbines in their class.

Tubercle technology is SO good that the US Naval Academy is testing whale-inspired tidal generators that capture the energy in the ocean’s tide.

So next time you’re outdoors and see a plant or animal with an odd shape or unusual behavior, ask yourself how it got there.  Chances are very good that it’s no mistake – something’s life depended on it!

Daniel Arneman, PhD, is an environmental analyst at the University of North Carolina at Chapel Hill.  Daniel works to measure and manage the campus’s carbon footprint and he also has a passion for learning about biomimicry.

Wave Energy

According to the US Department of Energy, wave energy off the coast of the United States is an estimated 252 billion kilowatthours a year, about 7% of the United States’ electricity consumption in 2008.  The West Coast of the US appears to be particularly good for harnessing wave energy.  Learn about and view images of all the technologies under development at the U.S. Department of Energy’s Marine and Hydrokinetic Technology Database.

Also, Pelamis Wave Power’s website contains videos and interactive models of The Pelamis Wave Energy Converter which was “the world’s first commercial scale machine to generate electricity to the grid from offshore wave energy and the first to be used commercially.”

Ocean Thermal Energy Conversion (OTEC) Resources

OTEC, or ocean thermal energy conversion,  takes advantage of the ocean’s natural thermal gradient to convert solar radiation to electric power.   This technology could be addressed with your students in the context of thermohaline circulation and the role of water as an energy agent.

The following organizations have some teacher-friendly OTEC resources:

NREL website includes an OTEC thermal resource map, showing where OTEC potential is greatest.

NOAA website also has diagrams and fact sheets available for download.

US Dept of Energy website includes information on the types of OTEC systems and the environmental and economic challenges of OTEC.

A 4 minute video about OTEC is available from the Ocean Energy Council’s website.  A poster highlighting major ocean energy technologies is also available for download.

Types of Hydropower

The US Energy Information Administration Energy for Kids site contains a useful overview of hydropower, including ocean energy technologies.
The US Department of Energy also has a useful overview of the different kinds of hydropower plants.

Tidal Energy Resources

Did you know there are five types of renewable ocean energy technologies? One of these is Tidal Energy, harnessing the power of the ocean’s predictable tides with undersea turbines.

Read about the World’s Largest Tidal Turbine, unveiled  in Scotland in August 2010.   The turbine could generate one megawatt (MW) of power, enough electricity for about 1,000 homes.

Also read about the SeaGen by Marine Current Turbines, Ltd. This prototype was installed in May 2008 in Northern Ireland.  This website contains images and an animation of the SeaGen that would be useful in the classroom.

Verdant Power has demonstration projects in the East River, New York and St. Lawrence River at Cornwall Ontario, Canada.  This website also contains images of tidal turbines and an animation.

To read more about Tidal Energy check out these resources:

US Department of Energy

US Energy Information Administration

Ocean Energy Council

Outer Banks Ocean Energy Corporation

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