The first ever lease application received to test ocean current energy equipment in the U.S. has been greenlighted by the Bureau of Ocean Energy Management (BOEM).
The Department of the Interior agency that oversees energy activities on the Outer Continental Shelf on Monday announced availability of a revised environmental assessment (EA) and its finding of no significant impact (FONSI) for lease issuance to conduct marine hydrokinetic technology testing offshore Florida.
Florida Atlantic University’s Southeast National Marine Renewable Energy Center (FAU SNMREC) applied to BOEM for a lease to deploy a proposed offshore ocean current turbine testing facility—the first of its kind in the world—in August 2011. The proposed lease area is contained within three Outer Continental Shelf blocks and is located approximately 9 to 15 nautical miles offshore Fort Lauderdale.
The project involves the installation of multiple anchored floating “test berths” to evaluate ocean current turbine designs. Each test berth will consist of a buoy anchored to the sea floor 13 miles off Fort Lauderdale, to measure ocean conditions and allow ocean current turbine prototypes to be deployed from vessels moored in the Gulf Stream. The first technology to be tested will be a research turbine designed and built at FAU that will collect drive-train performance and reliability data. According to the SNMREC, which has received close to $20 million in federal funding, the state of Florida, and private companies to deploy the test site, additional benthic surveys and a final sea trial of the buoy will be performed before installing the first test berth in early 2014. FAU’s research turbine is scheduled to be deployed in the Gulf Stream for the first time in mid-2014 after a series of towed tests.
BOEM published an EA for a 30-day public review period. “The EA considered potential environmental impacts and socioeconomic effects from issuing a lease and associated activities, including surveys, installing mooring and telemetry buoys, and testing of equipment designed to use the Florida current to generate electricity,” BOEM said in a statement.
Ocean current energy devices seek to harvest power from the ocean’s currents. Compared to tidal current energy technologies, which are being developed in several countries—and notably in Scotland—ocean current energy depends on relatively constant oceanic currents that flow in one direction. “While ocean currents move slowly relative to typical wind speeds, they carry a great deal of energy because of the density of water,” BOEM says in a website page dedicated to ocean current energy. “Because of this physical property, ocean currents contain an enormous amount of energy that can be captured and converted to a usable form. It has been estimated that taking just 1/1000th the available energy from the Gulf Stream would supply Florida with 35% of its electrical needs.”
A number of different current technology concepts are under development. Prototype horizontal axis turbines, similar to wind turbines, have been built and tested, and over the next five to seven years would be the most likely commercial development scenario, BOEM projects.
A number of engineering and technical challenges will need to be addressed before that can occur, however. These include overcoming bubble formation, prevention of marine growth buildup, reliability (since maintenance costs are potentially high), and corrosion resistance. “Because the logistics of maintenance are likely to be complex and the costs potentially high, system reliability is of particular importance. At present no open-ocean current turbines are deployed in U.S. waters—this technology is truly in its infancy,” the agency says.
Sources: POWERnews, POWER, BOEM, FAU
—Sonal Patel, Senior Writer (@POWERmagazine, @sonalcpatel)