The nation's first commercial hydrokinetic turbine, which harnesses the power from moving water without the construction of a dam, has splashed into the waters of the Mississippi River near Hastings, Minnesota.

The 35-kilowatt turbine is positioned downstream from an existing hydroelectric-plant dam and — together with another turbine to be installed soon — will increase the capacity of the plant by more than 5 percent. The numbers aren't big, but the rig's installation could be the start of an important trend in green energy.

And that could mean more of these "wind turbines for the water" will be generating clean energy soon.

"We don't require that massive dam construction, we're just using the natural flow of the stream," said Mark Stover, a vice president at Hydro Green Energy, the Houston-based company leading the project. "It's underwater windpower if you will, but we have 840 or 850 times the energy density of wind."

Hydrokinetic turbines like those produced by Hydro Green and Verdant capture the mechanical energy of the water's flow and turn it into energy, without need for a dam. The problem for companies like Hydro Green is that their relatively low-impact turbines are forced into the same regulatory bucket as huge hydroelectric dams. The regulatory hurdles have made it difficult to actually get water flowing through projects.

The Federal Energy Regulatory Commission has oversight of all projects that involve making power from water, and the agency has recently shown

signs of easing up on this new industry. In the meantime, the first places where hydrokinetic power makes in impact could be at existing dam sites where the regulatory red tape has already been cut.

“I am thrilled to support today's historic order that allows for harnessing more power from the Mississippi River,” FERC Commissioner

Philip Moeller said in a release. “I hope this is the first of thousands of similar projects that produce clean and renewable power from in-stream flows at existing dams.”

Moeller's enthusiasm could encourage other companies that are trying similar strategies to tap tidal or current power.

Verdant has been testing its own turbine design to capture tidal flow in New York's East River, but it hasn't been easy.

"Verdant has spent more money on permitting their East River project that than they did on hardware," said Roger Bedard, a researcher at the

Electric Power Research Institute, who has studied water-current–based energy generation.

Hydro Green's Stover hopes that his company's new unit will help shorten that regulatory process by generating environmental impact data that could ease concerns the turbines will disrupt river ecosystems and habitats.

And in the meantime, investors will continue to scour the planet for companies and technologies that could benefit from Barack Obama's plans to create green jobs. Congress already passed a bill this year to extend tax incentives for hydrokinetic projects through 2016.

"After the wind and solar craze, people said, 'What else is out there?'" Stover said. "The investment community is quite interested."

Image: Mark Stover/Hydro Green Energy, LLC

See Also:

WiSci 2.0: Alexis Madrigal's Twitter , Google Reader feed, and project site, Inventing Green: the lost history of American clean tech; Wired Science on Facebook.