"Lunar Power" comes to New York

This summer a Gristedes store on Roosevelt Island in New York will get half of its power from six tide-powered turbines in the East River. Unlike dam-based hydroelectric generators, which depend on rain or snowpack to keep current flowing and which shut down during droughts, newer "hydro- kinetic" systems exploit less capricious natural forces. "Lunar power" is the term offered by experts such as George Hagerman, a senior research associate at Virginia Tech and co-author of a recent EPRI marine-energy study. "You can't know if the wind will be up in an hour," he says, "but you can predict the tide 1,000 years from now." "It's local, reliable, renewable, and clean. Plus, it's out of sight," says Trey Taylor, president of Verdant Power LLC, the Arlington (Va.) startup developing the East River site. Read more in ::Business Week

Also read Treehugger posts like ::TidEl Harnesses Lunar Energy? Where our own Jacob Gordon predicted last August: "since the motion of the ocean is largely a result of the gravitational force of the moon as it literally bulges the sea from one side of the earth to the other, couldn’t we say this is lunar energy ? Solar is so clearly over."KINETIC HYDRO ENERGY CONVERSION SYSTEM AXIAL-FLOW ROTOR TURBINE

DESIGN

* Underwater windmills - unducted axial-flow rotor turbines
* Turbines comprise a thoroughly tested and documented (in conjunction with DOE, NYPA, NYSERDA, and NYU) "conformal" three-blade fan design
* Rotor is highly efficient over wide range of speeds without the complexity and reliability problems of variable-pitch blades
* Modular, self-contained turbine/generator units designed for direct submersion in tailrace, tidal, and river currents without costly civil works
* Designed to operate reliably underwater for extended periods
* Units designed to convert kinetic hydro energy to electric power in ranges from 25 kW to 250 kW depending on model size and water flow velocities (models planned; 25 kW, 50 kW & 100 kW)
* Power conditioning and interface modules, located onshore, designed to match output to power grid and to insulate customer's systems from equipment malfunctions

FABRICATION

* Turbine blades are formed of durable and lightweight composites
* Rotational molding processes used with high-strength thermoplastic materials
* Standard construction practices used to inexpensively build, deploy, and maintain nacelles
* Assembled with carefully selected off-the-shelf drive and generating components including brushless generators, high reliability gear trains, and double graphite/ceramic face seals for rotor shafts
* Self-cleaning screen for horizontally deflecting debris and fish away from turbine blades (also designing screenless, debris immune, and more fish-friendly turbine)
* Yaw bearing for bidirectional operation in tidal waters

DEPLOYMENT

* Units deployed in water currents with flow velocities of five feet per second (3 knots) or more, and in depths of at least six meters (20 feet)
* Can be deployed in hybrid configurations with other equipment such as fuel cells and storage batteries, or used alone
* Anchored to water bottoms, either by pylons, concrete bases, or other site specific anchoring devices, for reliable operation over extended periods without servicing or for ease in retrieval
* Significant electric power generated when multiple units are clustered into a "field" forming a group of generating units (each field producing power from 100 kW to 10 MW)
* Units can be used as "stand alone" systems for remote, off-grid locations or as "base power" systems for supplying electricity through transmission and distribution grids

OPERATION & ENVIRONMENT

* Mechanical power, derived from the turbines, is applied directly through a speed increaser to an internal gearbox/generator, or to a hydraulic pump that in turn drives an on-shore hydraulic motor and generator
* Requires no dams nor impoundments
* Poses no threat to the environment, nor to water quality
* Produces no by-products while in operation - clean and pollution free (no greenhouse gases)
* Harmless to marine life and allows safe fish passage