The Leading Edge

DOE introduces database for tidal energy resources

The U.S. Department of Energy, in partnership with the Georgia Institute of Technology, introduces a new database highlighting the energy potential available in the U.S. from ocean tidal streams.

This online database, called Assessment of Energy Production Potential from Tidal Streams in the United States, is an important step toward providing information that can improve the performance, lower the costs and accelerate the deployment of innovative waterpower technologies, DOE says. Georgia Tech has developed the first national database detailing the potential extractable energy from the nation’s tidal streams, a press release states.

Researchers at Georgia Tech Savannah used advanced regional ocean models to simulate tidal flows along the entire U.S. coastline. DOE’s Oak Ridge National Laboratory then validated the model’s accuracy, and the resulting data are now publicly available on the Internet at a website developed by the Georgia Institute of Technology:

The interactive database allows users to zoom and pan over maps of color-coded information on water depth, mean current speed and mean kinetic power density for tidal resources along the coasts of the contiguous U.S., Alaska and Puerto Rico. Users can produce maps on depth and power density using the database’s geographic information system (GIS) tools. Additionally, database users can select specific locations to build velocity and power density histograms, which are displayed as easy-to-read charts and graphs.

The data contained in this database is intended to provide general assessments of the available tidal stream kinetic power. It is not designed to be used for detailed site assessments, the developers say.

Initial results of PB150 ocean testing available

Pennington, N.J.-based marine energy developer Ocean Power Technologies Inc. announced that the first of its new generation utility-scale PowerBuoy devices, the PB150, has delivered better-than-expected results in ocean tests.

Power generated by the 150-kW PB150 has included peaks of more than 400 kW, with average electrical power capacity of 45 kW at wave heights as low as 2 meters. These levels of power exceeded OPT’s expectations of performance for this first PB150 deployment and verify that the system could provide a capacity up to 150 kW, on average, in higher wave conditions, OPT reports.

The power take-off system’s performance also exceeded expectations with respect to its energy conversion efficiency, a press release states.

This device was designed and developed by OPT to work in arrays of multiple PowerBuoys to operate on a commercial scale.

University proposes to deploy ocean current device off Florida

The U.S. Department of the Interior is beginning an environmental review for a leasing proposal to use ocean currents off Florida’s coast to generate electricity.

Florida Atlantic University has applied to the Bureau of Ocean Energy Management, Regulation and Enforcement for a lease to deploy an experimental demonstration device about 17 miles off the coast of Fort Lauderdale.

The Southeast National Marine Renewable Energy Center, which is operated by FAU, is exploring the potential for harnessing the powerful Gulf Stream, according to the National Oceanic and Atmospheric Administration.

The proposed lease would allow the center to deploy a single-anchor mooring and buoy similar to a naval weather buoy to test equipment that could tap the ocean’s current and generate electricity on the proposed leasehold. The devices to be deployed would be limited to 100 kW of capacity and 23-foot-diameter rotors, according to the application with federal regulators.

If approved, the university’s limited lease would last five years but would not authorize the commercial production or transmission of energy.

Esri offers map of oceans and coastal areas

The Ocean Basemap is a cached map service in ArcGIS Online designed to provide access to ocean data.

Developed by Esri, the Ocean Basemap includes bathymetry, marine water body names, undersea feature names and derived depth values in meters for the entire globe. Land features include administrative boundaries, cities, inland waters and roads overlaid on land cover and shaded relief imagery.

The basemap was built using publicly available ocean data from a variety of sources, such as the General Bathymetric Chart of the Oceans, the IHO-IOC GEBCO Gazetteer of Undersea Feature Names and the National Oceanic and Atmospheric Administration. Scales range from 1:1,000,000 to 1:36,000.

Users can contribute data to the Ocean Basemap, and Esri plans to update it monthly.

The basemap is available at

Geographic Information System software developed by Esri is used by more than 300,000 organizations worldwide, the company says.

Waterotor low-head system to be tested in Canada

Waterotor Energy Technologies Inc. of Ottawa, Ontario, Canada, is preparing to test is Waterotor-Generator low-head hydrokinetic system.

The unit incorporates a Savonius-type rotor, which is a stylized drum with curved double-sided blades attached to a flow-assisting drum and flow stators that capture water flow and extract power. This rotor relies on torque rather than higher-speed water velocities, allowing it to operate in nearly any flow speed. The Waterotor-Generator can extract power from water flows from 2 to more than 9 miles per hour, the company says.

The unit can be either a buoyant device tethered to the bottom of the river by anchors or a heavier than water device that can be lowered from a bridge, barge, boat or buoy. The unit is scalable from a few kilowatts up to megawatts, Waterotor Energy Technologies says.

The company is building a test device that was to be demonstrated in a tributary of the Ottawa River in summer 2011.

Columbia Power advances development of SeaRay

A SeaRay wave energy prototype developed by Columbia Power Technologies has been operating in Puget Sound off the coast of Oregon since March.

This sea trial represents a key milestone in moving from the pre-commercial stage toward commercial viability, the company says. The device was to operate for a few months to capture data.

The SeaRay point absorber features a heave- and surge-energy capture design, allowing it to access the full potential of a wave, thc ompany says. This is a direct-drive system. It can survive and produce electricity in extreme weater conditions in a small environmental footprint, Columbia Power Technologies says.

In September 2009, the company was selected as part of a round of U.S. Department of Energy funding to improve the viability and performance of hydrokinetic and conventional hydro plants.

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Renewable Energy World's content team members help deliver the most comprehensive news coverage of the renewable energy industries. Based in the U.S., the UK, and South Africa, the team is comprised of editors from Clarion Energy's myriad of publications that cover the global energy industry.

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