That's the end goal of Verdant Power’s ongoing East River experiment, which yielded construction of the world’s first array of grid-connected hydrokinetic turbines. The RITE Project, short for Roosevelt Island Tidal Energy, deployed six three-blade units about two years ago that converted the kinetic energy from tidal and river currents into electricity. Now Verdant Power is seeking government approval to expand the installation to 30 turbines in the waterway’s East Channel, lying between Roosevelt Island and Queens.
More dramatic, Verdant’s draft license application filed this fall with the Federal Energy Resource Commission, the agency charged with hydropower oversight, proposes installing an additional 100 units in the West Channel’s UN security zone that is closed off to boat traffic. This latter installation will require a separate license. A full expansion of the project, which would entail installing nearly 300 turbines, has the potential to generate 10 megawatts of average annual power.
The company's six-turbine prototype was created to gather data for its FERC license application. Although the turbines logged an unprecedented delivery of 80 megawatt hours of grid-connected electricity to a nearby Gristede's supermarket and parking facility, the turbines also malfunctioned twice, leaving them defunct for most of the time they were in the water. In October, Verdant installed improved aluminum magnesium alloy rotors which have kept the turbines turning since then.
While the turbines were operational, Verdant used a combination of hydroacoustic transducers and state-of-art ultrasound imaging to monitor how fish were reacting to the functioning turbines. According to company president Trey Taylor: “For the most part there is no impact on fish.”
“What we witnessed was safe fish passage,” says Taylor. “We gathered a lot of data to be analyzed to validate or verify what we witnessed, which in essence was fish just swimming around the turbines.”
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Environmental impact
Verdant’s environmental monitoring is a crucial aspect of this project. The East River is a tidal strait that connects Upper New York Bay with the Long Island Sound. The waterway harbors a broad diversity of fish species, including the endangered shortnose sturgeon. But behavior and migration patterns of the river’s marine life are varied and, to a large extent, unknown.
To date, Verdant claims to have spent more money on environmental testing than on the turbines themselves – but the company's efforts have not eliminated concerns.
In December, FERC invited comments on Verdant’s draft application. Responding agencies include the state Department of Environmental Conservation (DEC), the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, and the United Marine Division Local 333, a longshoreman’s association. DEC raised the most detailed criticisms of the project, indicating dissatisfaction with Verdant’s environmental impact studies. One comment letter said that Verdant’s monitoring plan for the 30 turbine build-out is not well defined, existing data are inconclusive, and final data reports were not provided for review.
