East River Fights Effort to Tap Its Currents For Electricity
By ANTHONY DEPALMA
New York Times
August 13, 2007

From the eastern edge of Roosevelt Island, the past and perhaps the future of New York power are on display.
Just south of the Roosevelt Island Bridge to Queens rise the smokestacks of KeySpan's giant Ravenswood electricity generating station, a behemoth that runs on natural gas and fuel oil. North of the bridge, black cables snake out of the churning surface of the East River. They connect a makeshift control room inside an old shipping container on the island to a battery of futuristic mechanisms that could shape an energy future that does not pollute or use foreign oil -- if a five-year-old company named Verdant Power can work out all the bugs.

Weeks after they were formally dedicated by Mayor Michael R. Bloomberg, six underwater turbines that turn the river's currents into electricity have been shut down for repairs and a basic redesign. The East River's powerful tides have been wreaking havoc with the giant turbine blades since the first two were installed in December. ''But the good thing is that there's more power in the East River than we thought,'' said Mollie E. Gardner, a geologist for Verdant Power, which owns the equipment.

This is the reality of new energy projects, which often seem more attractive on paper than they do in practice. Verdant's principals, along with the state officials who have supported the project with large grants, say the setback is only temporary, even expected -- a way to work out the kinks before moving onto the next, expanded phase.

Despite a string of mishaps that has taken a bit of the luster off the project, there is still sufficient optimism about tidal power to attract investments, and even some old-fashioned competition. It has been a rough eight months for Verdant. Days after the first two turbines were lowered into the water, the East River's powerful currents sheared off the tips of several blades about a third of the way down.

New blades were ordered, made of a cast aluminum that theoretically would hold up better. They replaced the ones that were broken, and were also installed on four more turbines that were lowered into the river's eastern channel earlier this year. Together, the turbines were capable of producing about 1,000 kilowatt hours a day of clean electricity. But the East River tides have proved too formidable even for the stronger blades, putting excessive strain on the bolts that hold them to the turbine hubs.

To keep them from coming apart, all six of the 20-foot-tall mechanisms, which resemble ship propellers on masts, have been shut down for repairs and may not be back in operation until November. ''The only way for us to learn is to get the turbines into the water and start breaking them,'' said Trey Taylor, the habitually optimistic founder of Verdant Power.

From the surface of the river, there is no sign that anything has gone wrong. The Gristedes supermarket and the Roosevelt Island Motorgate parking garage, which were being powered with electricity generated by the turbines, have not gone dark. They are still plugged into the city's traditional electricity grid and may well be receiving electricity generated at the old Ravenswood plant across the river. While KeySpan is the largest distributor of natural gas in the Northeast, it is also the largest privately owned generator of electricity in New York State, and its Ravenswood station provides about 25 percent of New York City's electricity needs.
KeySpan also has taken an interest in its upstart neighbor. The corporation has entered into a strategic partnership with Verdant to pursue tidal energy.

The idea of generating electricity by harnessing the power of a flowing river -- called hydrokinetic energy -- is attracting growing attention. Basically, the East River turns the turbines' blades as it flows past. The turbines, like windmills, generate electricity that is channeled through wires to a central control unit and from there to the existing electricity grid. Hydro turbines have a few advantages over windmills. While winds are erratic, tides can be charted by the minute, which allows power companies to know exactly when the turbines will be generating power.

Verdant chose the East River because it is fast-flowing and is close to where the energy it produces would be used. The East River's unique character also played a role. The river's tide changes direction each day, flowing north and then turning around and pushing toward the ocean. But just before the tide shifts, there is a window of about 45 minutes of calm that allows Verdant to install, repair or tweak its turbines. The turbines -- five generate electricity and one houses the dynamometer that measures water rotational speed -- have been installed on the bottom of a narrow strip of the river's eastern channel. Commercial traffic continues to use the remainder of the east channel and the deeper, more navigable western channel.

Mr. Taylor said that despite the difficulties, the East River project has generated about 7,100 kilowatt hours of electricity, which he said was a world record for hydrokinetic power. The turbines operated, on average, about 17 hours a day until they were shut down this summer. The project has received about $2.5 million in support from the New York State Energy Research and Development Authority, an agency that promotes energy alternatives.

Paul D. Tonko, president of the authority, said that the technical problems had not been a major concern and that he was satisfied with Verdant's progress. An analysis of the project's early production record indicates that Verdant is producing energy for about 7 to 8 cents per kilowatt hour, he said, slightly higher than traditional sources at current prices for natural gas and fuel oil.

Once the project is fully developed -- Verdant plans to install as many as 300 turbines in the East River -- it could generate enough electricity to power more than 8,000 homes and compete head-to-head with traditional sources, Mr. Taylor said. But a few obstacles still stand in the way. Mr. Taylor said the company has had to spend more than $2 million to study the impact that the turbines might have on fish in the East River. The water is monitored 24 hours a day with sonar equipment to see whether fish are harmed by the blades, which move at a comparatively languid 32 revolutions per minute.

The company has found that the few fish who are picked up by the sonar tend to swim around the blades.
''So far, there haven't been any strikes,'' said Ms. Gardner, the geologist who works for Verdant. Still, federal regulators want Verdant to conduct studies on species like sturgeon and some turtles that are rarely seen in the East River. ''For a start-up company, this is getting pretty hard,'' Mr. Taylor said. Verdant is also facing the prospect of competition -- not so much from giants like KeySpan but from other alternative energy start-ups. One company, Oceana Energy, recently was granted a federal permit to install turbines in the East River just north of Roosevelt Island.

Mr. Taylor's company had accused Oceana of intending to simply hold the permit until it became more valuable. John C. Topping Jr., an Oceana founder, said the company is developing its turbine technology. It has about a dozen sites, including one in San Francisco and several in Alaska. ''Our preliminary studies of the East River make it look very promising,'' Mr. Topping said. ''Our project is not going to detract at all from the other.''

Verdant recently withdrew its protest of Oceana's permit application, deciding instead to focus on fine-tuning its own technology. And it expects that competitorswill be surprised when they try to lasso the wild waters where the East River enters the area known as Hell Gate, between Wards Island and Astoria, Queens. ''I wish them the best of luck,'' Ms. Gardner said.