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Alexander's Marvelous Machine
Page 2

In September 2003, a turbine built by the Norwegian company Hammerfest Strom became the first to send free-flow hydropower to a grid. Anchored in deep water off Norway's coast, where tidal currents are strong and constant, the Hammerfest turbine is massive, with three 30-foot-long blades. The United Kingdom has similar plans for its abundant ocean currents, and in 2003 pledged £960,000 ($1.8 million) to help Marine Current Turbine install a double-propeller turbine measuring 45 feet across off the coast of Devon. Verdant Power will soon install six of its turbines in New York City's East River, making the company the first in the country to send free-flow hydropower to the grid.

All of these machines are so-called axial-flow turbines. The type of turbine most often found on wind farms, they are shaped and operate something like a propeller. Gorlov's invention, however, is a cross-flow turbine. It spins much as you'd expect from its appearance, making it extremely versatile. It can be mounted either horizontally or vertically, stacked in rows like spools on a string, and placed in water as shallow as three feet. (Most axial-flow turbines require eight feet or more.) The blades of an axial-flow turbine will turn only if they face the current, whereas Gorlov's turbine will function regardless of the direction of the flow, ideal for tidal waters.

For its design, Gorlov credits in part French engineer Georges Jean-Marie Darrieus, who in 1931 received a U.S. patent for a turbine whose blade would be shaped in a way that was "analogous to that of the wings of birds." This, he knew, would increase efficiency and make the turbine spin much faster than the wind or water hitting it. On paper, the Darrieus turbine had magnificent potential, but the real world was too much for it. The ruler-straight blades had a tendency to pulsate wildly, rip from the axle, or snap in two. Gorlov corrected Darrieus's engineering error: By twisting the blades slightly, a bit like a strand of DNA, he eliminated the vibrations. Gorlov received his first patent for the turbine in 1994.

Today, the narrow blades are modeled on the airfoil profile of a Boeing 727 wing. That slight helical twist not only removes the vibrations but also makes Gorlov's turbine a champion spinner. Placed in a moving current, it kicks into motion almost instantly and within seconds will turn faster than the speed of the water hitting it. Tests conducted at the Marine Hydrodynamics Laboratories at the University of Michigan in 1998 and 1999 showed that the Gorlov Helical Turbine will take off in water moving as slowly as two knots and can capture about 35 percent of the kinetic energy of the current.

For all the documented potential of free-flow hydropower, U.S. companies, such as the San Antonio-based GCK Technology, which bought the rights to Gorlov's turbine, face some formidable political and economic realities. Federal funding for hydropower research and development in 2003 amounted to $5 million, but free-flow projects received exactly zero. The only R&D money for free-flow hydropower in the United States comes from private investors willing to shoulder the risk and from a handful of states, including New York and Massachusetts, that administer their own renewable energy funds, paid for by a small surcharge on residential electricity bills.

The rising cost of traditional energy sources, increased concern over both energy security and the environmental impact of fossil fuel use, and new policy incentives such as renewable portfolio standards (which require that a certain percentage of electricity be derived from a renewable energy source) have all combined to sharpen competition. "There are literally hundreds of clean-energy technology companies fighting for public and private money right now," says Dan Reicher, president of New Energy Capital and assistant secretary of energy in the second Clinton administration.

The federal budget line for renewables peaked under Clinton and has now declined, with most funding being shifted over to hydrogen research. That may sound like a good thing, but developing hydrogen is a very long-term solution to energy problems that need fixing now. The shift in priorities, notes Reicher, comes at the expense of core renewables such as wind, solar, and biomass, which could provide solutions in the near term.

Developing a new hydroturbine is not as simple as, say, developing a new kitchen gadget. Lewis Branscomb, professor emeritus of public policy and corporate management at Harvard University's John F. Kennedy School of Government, has spent years studying the movement of perfectly good ideas into the marketplace and has concluded that all inventions, before becoming commercial products, must successfully cross a pernicious place he calls the Darwinian Sea. (Others, less optimistically, call it the Valley of Death.) On one shore is the invention and its creator; on the other shore is the market economy, mass production, and wealth. Branscomb's sea is "full of sharks and shoals and storms" -- funds can dry up, parts can break, regulations can bog an idea down, investors can decide that there's no market -- and few inventions manage to complete the journey.

Who Owns This River?
Who Owns This River?
Europe's Black Triangle Blooms

Gorlov Helical Turbine



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Illustration: Jim Kopp

OnEarth. Spring 2005
Copyright 2005 by the Natural Resources Defense Council