Hydropower, Storage

The Leading Edge

Issue 7 and Volume 30.

Free Flow Power turbine deployed in Mississippi River

Renewable energy developer Free Flow Power Corp. has been operating its first full-scale hydrokinetic turbine-generator in the Mississippi River since June 20, 2011.

In February and November 2010, the company tested its turbine in a controlled flow at the U.S. Geological Survey’s Conte Anadromous Fish Laboratory at Turner Falls, Mass.

The current deployment represents the first time the equipment has generated electricity in the Mississippi River. This operation is the culmination of three years of research and development by Free Flow Power, funded through a combination of private capital and a $1.4 Million Advanced Water Power grant from the U.S. Department of Energy.

The turbine is installed on a research surface platform that includes instrumentation to allow the Free Flow Power team to monitor key performance metrics, such as stream velocity, electrical current and voltage. The Dow Chemical Company is supporting Free Flow Power’s efforts by hosting the floating demonstration installation at the company’s dock at Plaquemine, La.

After several weeks and many hours of continuous generation, Dr. Ed Lovelace, chief technology officer for the company, is satisfied with the results. “Performance to date has been consistent with our design predictions, which makes it very competitive with published data on similar devices being developed around the world,” said Lovelace. “The equipment is handling the Mississippi River conditions without power interruptions or degradation.”

Free Flow Power is pursuing approvals from state and federal regulators, led by the Federal Energy Regulatory Commission, to install arrays of its hydrokinetic turbines at various locations in the Mississippi River.

Free Flow Power is a renewable energy company focusing on hydropower, hydrokinetics and pumped storage as reliable, cost-effective sources of electricity and grid stability.

OPT deploys PowerBuoy for U.S. Navy program

Marine energy firm Ocean Power Technologies Inc. has deployed its PowerBuoy wave energy device for sea trials.

This deployment is an autonomous PowerBuoy designed and manufactured by OPT under the U.S. Navy’s Littoral Expeditionary Autonomous PowerBuoy (LEAP) program for coastal security and maritime surveillance. The LEAP structure, incorporating a unique power take-off and on-board energy storage system, is significantly smaller and more compact than the standard PowerBuoy.

It provides persistent, off-grid clean energy in remote ocean locations for a wide variety of maritime security and monitoring applications, OPT says.

Under the LEAP program, OPT has integrated its autonomous PowerBuoy with radar network and communications infrastructure from Rutgers University’s Institute of Marine and Coastal Sciences, in partnership with CODAR Ocean Sensors. This PowerBuoy provides power at the lower levels needed for the vessel detection and tracking system, enabling maritime surveillance in the near coast, harbors and littoral zones worldwide, OPT says. Mikros Systems Corp. provided data and systems architecture support for the PowerBuoy/radar network.

Currently, systems requiring remote power at sea often are powered by diesel generators, which need frequent maintenance and fuel replenishment. The LEAP system was developed by OPT to provide constant power in all wave conditions for the sea-based radar and communications system. The company’s proprietary power management techniques and onboard energy storage capability enable operation even in extended zero-wave sea conditions, OPT says. In addition, the system has been engineered to require no maintenance for three years.

The LEAP system was deployed in August by a U.S. Coast Guard vessel and will be ocean-tested about 20 miles off the coast of New Jersey. It will be integrated with the Rutgers University-operated, land-based radar network that provides ocean current mapping data for the National Oceanographic and Atmospheric Administration (NOAA) and U.S. Coast Guard search and rescue operations. The ocean test of the LEAP vessel detection system will demonstrate dual-use capability of the radar network and verify OPT’s technology as a source for systems requiring remote power at sea, the company says.

OPT is a renewable energy company specializing in offshore wave power technology.

Resolute completes tank tests of prototype unit

Resolute Marine Energy completed scale-model tank tests of a second- generation SurgeWEC prototype.

This testing took place in June at the Bureau of Ocean Energy Management, Regulation and Enforcement’s Ohmsett National Oil Spill Response Test Tank Facility in Leonardo, N.J.

Ohmsett, at the Naval Weapons Station Earle Waterfront, is the world’s largest saltwater tow/wave tank and is designed to evaluate the performance of equipment under realistic but safe environmental conditions, says Nicholas W. Pardi, media officer with BOEMRE (formerly MMS). Ohmsett features an outdoor, above-ground concrete test tank that is 203 meters long, 20 meters wide and 3.5 meters deep. The tank holds 10 million liters of water.

The facility is equipped with a wave generator capable of producing different wave types and spectrums. The tank also is equipped with three movable bridges with tow speeds of up to 6.5 knots, and speed can be adjusted by increments of 1/100 knot to simulate ocean current flow. In addition, the testing facility features an underwater photography and video imaging system.

Resolute’s wave energy converter is a one-degree-of-freedom heaving buoy that captures the vertical energy of wave motion and uses it to directly drive a linear generator. The unit is slightly negatively buoyant and has a subsurface drag plate to supply damping forces. Buoyancy is controlled via a cluster of modules attached to the top of the submerged portion of the unit. These units do not require a rigid connection to the ocean floor and can be deployed both near shore (in water 10 to 30 meters deep) and in deeper water.

Boston-based Resolute plans to perform ocean tests this fall using a unit at the same scale as the prototype tested.

In December 2008, the U.S. Department of Energy announced a plan to establish a research, testing and product development partnership with Resolute. The National Renewable Energy Laboratory worked with Resolute to establish a Cooperative Research and Development Agreement partnership, beginning in the first quarter of 2009.

IEC subcommittee working on marine energy standards

Technical committee 114 of the International Electrotechnical Commission is working on seven marine energy standards.

The seven standards under development (labeled IEC/TS 62600), and their status, are:

  • Part 1: Terminology, circulated draft;
  • Part 10: The assessment of mooring system for marine energy converters, approved new work;
  • Part 100: Power performance assessment of electricity producing wave energy converters, second committee draft;
  • Part 101: Wave energy resource assessment and characterization, first committee draft;
  • Part 2: Design requirements for marine energy systems, approved new work;
  • Part 200: Power performance assessment of electricity producing tidal energy converters, first committee draft; and
  • Part 201: Tidal energy resource assessment and characterization, first committee draft.

These standards are intended to support efforts by the International Energy Agency’s Ocean Energy Systems group to recommend best practices for the effective networking and integration of electricity from wave and tidal energy devices.

The committee was formed in 2007 to prepare international standards for marine energy conversion systems, with a primary focus on conversion of wave, tidal and other water current energy into electrical energy. The TC has 14 participating members and four observing members. Chairman of the committee is Melanie Nadeau of the CANMET Energy Technology Centre in Ottawa, Ontario, Canada.

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. This is a direct-drive system. It can survive and produce electricity in extreme weather conditions in a small environmental footprint, Columbia Power Technologies says.

Columbia Power Technologies’ goal is to deliver megawatt-scale devices.

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 technology and conventional hydropower plants.

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