DOE Reports Confirm United States' Immense Wave and Tidal Energy Resources
Two U.S. Department of Energy (DOE) reports provide back-to-back confirmation that the potential for electricity from coastal wave and tidal stream energy could reach as high as 15 percent of the total of current U.S. electrical demand.
The first, prepared with the assistance of the Electric Power Research Institute (EPRI), using a specially prepared, 51-month Wavewatch III database developed by NOAA (the National Oceanographic and Atmospheric Administration), estimates wave power along the U.S. continental shelf in kilowatt-hours (kWHs) based on the accepted assumption that wave power densities are aggregated across a unit diameter circle, and mapped out to 50 nautical miles from shore.
Partners in the study/assessment included the Virginia Tech Advanced Research Institute (VT-ARI) and the National Renewable Energy Laboratory, or NREL (one of 12 labs operated by the DOE, and the only one involved in research, development, commercialization and deployment of energy efficiency and renewable energy technologies).
According to the report, the total available wave energy power estimate is 2,640 terawatt hours per year (TWH/yr), with 590 TWH/yr coming from the West Coast, 240 TWH/yr from the East Coast, 80 TWH/yr from the Gulf of Mexico, 1,570 TWH/yr from Alaska, 130 TWH/yr from Hawaii, and 30 TWH/yr from Puerto Rico.
Of that, less than half is recoverable, but even this 1,170 TWH/yr represents a significant amount (29%) of electricity, compared to total U.S. electricity use of 4,000 TWH/yr. Even after reducing estimates to account for what some critics consider “double-counting,” the resource still represents about 15 percent of U.S. energy use.
The second report was a cooperative effort between the DOE and Georgia Tech (funded through the DOE’s Office of Energy Efficiency and Renewable Energy, or EERE), and collates data from ROMS (the Regional Ocean Modeling System) suggesting that – at an assumed extractable level of 15 percent (the exact figure is unknown) – tidal streams in Alaska, Puget Sound, California, Massachusetts and Maine could provide a documented 17 terawatt hours (TWh) of energy per year, the lion’s share of that coming from the Cook Inlet in Alaska.
Tidal power is also available in Washington, Oregon, New Hampshire, New York, New Jersey, North and South Carolina, Georgia and Florida (in order of potential). In some of the locations, areas called “hotspots” -- measuring a few hundred kilometers square and at depths greater than 100 meters -- power potential is in excess of 8 kilowatts per square meter, and could provide more than adequate reliable supplies of localized electricity.
Both wave energy and tidal energy are emerging renewable energy sources whose technology is only now beginning to catch up to the remarkable energy potential inherent in ocean water. Wave power, as its name suggests, extracts the kinetic energy of ocean waves off the continental shelves in deeper regions of water.
Tidal wave power is a result of the effect of ocean currents on the land, for example during high tides, when ocean water “slips” sideways after reaching the beach or shore.
The first commercial-scale wave power installation in the U.S. was off Reedsport, Oregon, by Ocean Power Technologies, Inc. (NGM: OPTT). This commenced in 2010, which demonstrates just how new the technology is – at least in the U.S (though Europe is not far ahead, having run its first test of a wave power machine in 2004 and commercial deployment in 2008).
New as these technologies may be, they offer distinct advantages over solar arrays and wind farms located on land – advantages which the UK and other European nations seem bent on harnessing, while the U.S. backs off – presumably as a result of President Barack Obama’s reluctance.
With the exception of the U.S. military, notably the Air Force, which in 2011 demonstrated the tremendous potential of the ocean to generate energy using its research facilities at the Air Force Academy campus in Colorado Springs, Colorado.
This year, the DOE also plans to release additional program-funded assessments of ocean current and ocean thermal resources.
Jeanne Roberts is a freelance writer on environment and sustainability issues. In her previous life, she worked as both a reporter and a communications specialist for a major public utility. Her most recent book, Green Your Home, approaches environmentalism from a consumer’s perspective.
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