Dec 5 - McClatchy-Tribune Regional News - Tom Charlier The Commercial Appeal, Memphis, Tenn.

Deep beneath the swirling, shifting surface of the Mississippi River, powerful forces are going to waste.

During even the lowest of river stages, the Mississippi's current can exceed 6 mph and push more than 1.5 million gallons of water per second past any given point at Memphis.

No one's ever really tried to harness all that energy -- until now.

Three companies this year have received preliminary federal permits to pursue projects that involve the installation of submerged turbine generators at more than 60 locations along the Mississippi, including one at Memphis.

If the firms receive final licensing by the Federal Energy Regulatory Commission, large-scale construction could begin within three years on projects employing an emerging type of generating technology known as hydrokinetic power.

Unlike conventional hydro-electric facilities, the projects won't require ecologically devastating dams or river diversions. Mounted on pilings in the river bed, or on bridge piers or even barges, the turbines will spin in the natural current, producing clean, renewable power for sale to the electrical grid or individual industries.

"They look like an underwater jet engine, but they function like a windmill," said Jon Guidroz, director of project development for Free Flow Power Corp., a Massachusetts-based firm that plans the largest network of turbines along the Mississippi.

In addition to the initiatives along the Mississippi, FERC has approved preliminary permits for hydrokinetic initiatives on other rivers, including the Missouri and Ohio, as well as projects involving wave-powered turbines along the West Coast.

The 55 turbine sites planned by Free Flow on the Mississippi between St. Louis and the Gulf of Mexico would cost $3 billion and generate 1,600 megawatts of electricity. That's more power than typically produced by a nuclear reactor unit and roughly twice the output of the Tennessee Valley Authority's Allen Fossil Plant in Memphis.

Free Flow plans to install clusters of six turbines on pilings and bridge piers. With a current of 2 meters per second, each cluster would generate 60 kilowatts, but the output could increase to 240 kilowatts if the flow is 3 meters per second, Guidroz said.

The company's turbines will be about 10 feet in diameter and installed well below the minimum 9-foot depth of the navigation channel. The Mississippi reaches depths of up to 110 feet in some of the river bends under consideration as turbine sites.

"The reason we're starting so large is we think it's important to achieve economies of scale," he said.

"This is a massive river... There's a lot of potential to harness energy."

Memphis would be a "lead site" for the Free Flow network, a place where the technology would have a high profile for display, Guidroz said.

Another firm proposing the turbines is Hydro Green Energy, a Connecticut-based firm planning 5-megawatt projects near Natchez and Vicksburg, Miss., and elsewhere.

Company spokesman Mark Stover said Hydro Green's turbines are suspended from the surface or mounted on barges. The firm already is installing an initial unit in Minnesota.

The companies received the preliminary permits as FERC somewhat revised its licensing rules to provide a streamlined process for some hydrokinetic projects.

The permits give the firms exclusive rights to study specific reaches of the river. To ensure companies don't just use the authorizations to tie up activity on parts of the Mississippi, the permits contain deadlines for certain reports and progress.

"If they aren't complying with the terms of the permit, we cancel it," said FERC spokesman Celeste Miller.

After the studies are completed, the firms can seek full licenses, which typically are good for periods of 30 to 50 years, to generate power in the river. Free Flow intends to submit a 1,000-page pre-application document to FERC in January, Guidroz said.

But FERC isn't the only agency that will review the hydrokinetic projects. The Corps of Engineers, which regulates navigation and flood control along the river, must ensure the turbines don't interfere with other uses of the Mississippi.

"We're not going to let them put something in the river that's going to damage or cause harm to the towing industry," said David Berretta, chief of hydraulics for the corps' Memphis district.

Developers say their projects will be not only compatible with other river-users, but environmentally sensitive, as shown in studies reporting virtually no harm to fish and aquatic life.

Free Flow's submerged generating units also will not use any chemical lubricants, eliminating the danger of polluting the river.

Environmentalists, who have long complained about the harm caused by dams, are tentatively optimistic about the hydrokinetic power projects.

"It's sort of an experiment. We've never seen one," said John Seebach, director of the hydropower reform initiative for the group American Rivers.

"I'm all for putting them in the water as long as you say up front, 'These are the impacts we can live with, and if bad things happen we'll take them out.'"

A major challenge for the initiatives will be designing ways to protect the turbines from the logs, sand and debris carried by the Mississippi's current. The firms say they are designing their projects to deal with the hazards.

"I think there's tremendous potential in the Mississippi River. The challenge will be how developers balance all of the interests," said Hydro Green's Stover.

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