In the depths

In the depths Hydrokinetic power plants operate below barge traffic.

      Something is quietly stirring in the river water at Hastings, Minn., just downstream from the Army Corps of Engineers' Lock and Dam No. 2. While it's not a strange creature lurking in the depths, it is a new sight to the waterway's users.
      Earlier this year, Houston-based Hydro Green Energy installed the first of two barge-mounted hydrokinetic power plants. The second unit is expected to enter service next spring.
      Hydrokinetic power refers to the generation of electricity from moving water without dams or diversionary structures typically used at conventional hydropower plants. Hydro Green's unit will produce 100 kilowatts of uninterrupted power, which will feed back to the electric grid.

Hydro Green prepares installation of its first barge-mounted hydrokinetic power plant in Hastings, Minn. (Photo: Hydro Green Energy

   After extensive testing by the company, the Federal Energy Regulatory Commission signed off on the project in Hastings in December.
      The Corps plays a major role in evaluating and approving these types of projects. The agency must ensure that any proposed hydropower-generation equipment doesn't hurt the environment or impede barge traffic. 'Anytime we have the opportunity where we're not altering our flows and capacity, it's something we like to do,' said Mike Ensch, the agency's chief of operations and regulatory.
      Hydropower has been added at Corps dams by local utilities over the years, such as Canyon and Lewisville, Texas, and Bluestone, W.Va. Other facilities are underway by AMP-Ohio at the Smithland and Cannelton locks and dams, with three more planned. These facilities were built on the river banks along the lock and dam spillways, Ensch said.
      Suspended or anchored hydrokinetic equipment tAakes advantage of free-flowing river currents. While the concept is quite ancient, it has recently become part of the country's efforts to develop non-fossil fuel-based energy sources, such as wind, solar, biomass and geothermal.
      Hydro Green plans to develop hydrokinetic projects across more than a dozen states for a total of 500 megawatts of power.
      Other firms are seeking federal approval to install their own hydrokinetic equipment in U.S. waterways. Free Flow Power of Gloucester, Mass., has received 55 FERC permits to conduct tests at Mississippi River sites between St. Louis and Plaquemines, La.
      Free Flow's 1.4- and 3-meter-diameter machines, which resemble wind turbine blades contained within an open-ended cylindrical shell, would be attached several at a time to underwater pylons well below surface barge traffic.
      In a 2007 policy statement, FERC estimated that hydrokinetic technologies, combined with the existing hydropower capacity, could eventually produce 20 percent of the country's electric supply.