A New Green Energy Idea: Harvesting Deep Ocean Currents

A new type of ocean power generator could harvest the steady, reliable energy of deep ocean currents, and a group of companies are working together to place the first 1-megawatt system on the seafloor. The companies are currently raising money for the demonstration project and say they're investigating R&D funding from the U.S. Navy and the Department of Energy. 

The grid connections and system software are being designed by Eaton Corporation, a power management company with experience in linking renewable energy sources like wind and solar farms to the grid. The 1-MW turbine will come from Triton, a Florida-based company that primarily builds deep-ocean subs. Eaton representatives say the 1-MW demonstration project could easily be built up to a utility-scale current farm by adding more turbines. 

Deep ocean currents are generated by differences in the ocean's salinity and temperature around the continents. They run at a constant speed of about 3 to 5 knots (5.5 to 9 kilometers per hour), according to Eaton's Department of Defense account development manager Jim Spaulding. "You’d be amazed at how steady-state these deep ocean currents are," Spaulding told me. "That’s the appeal: It’s very, very consistent." 

The consortium hasn't picked out a spot yet for its demo, but Spaulding mentioned the waters off the coast of Florida as one attractive option. There, strong currents can be found within a couple of miles from shore and at relatively easy-to-reach depths of 30 to 150 meters, he said. Eventually, Eaton plans to build systems at depths of 300 to 500 meters. 

While the ocean energy industry is in its infancy, there's been a lot of excitement in recent years over new turbine technologies and demonstration projects. In the United States, the first tidal station began providing power to the Maine grid in September, and a wave power project is intended for Oregon's waters (although the installation of the wave power turbine was recently postponed until spring 2013). Outside the United States, companies like Pelamis Wave Power and OpenHydro are pursuing commercial-scale wave and tidal power stations, respectively.

Image: Triton Energy Systems, LLC

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