Forget massive and costly hydroelectric dams: the future of water-based energy could lie, literally, below the surface in the form of hydrokinetic turbines.

Basically underwater turbines that generate energy via waves, tides and currents instead of wind, these hydrokinetic devices are enjoying their first commercial test run in the US, thanks to a new installation in the Mississippi River.

Wired.com reports this week that the Houston-based Hydro Green Energy has installed one 35-kilowatt hydrokinetic turbine in the Mississippi River in Hastings, Minnesota. The turbine will supplement the energy already being generated by a hydroelectric dam in the area, and will soon be joined by a second underwater turbine that will boost the facility’s energy output by another 35 kilowatts.

“This is a creative solution to meeting electricity demand using renewable resources,” said Joseph T. Kelliher, chairman of the Federal Energy Regulatory Commission (FERC), upon the agency’s granting approval to the turbine installation earlier this month.

“(I)t’s only fitting that this project is located in the Mississippi River, America’s most well known river,” added Wayne Krouse, chairman and CEO of Hydro Green Energy.

The hydrokinetic turbines will both be suspended from a floating barge downstream of the hydroelectric dam.

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

In fact, Hydro Green Energy already has other watery energy sources in its cross-hairs. Once both turbines are up and running in Minnesota, the company has its sights set on a 70-megawatt installation in another iconic US waterway: the Niagara River.

Tags: Hydro Green Energy, hydrokinetic energy, Mississippi River, tidal energy, wave energy