The most common hydroturbines use the waters pressure energy to and convert it into work. The biggest difference between this principle and hydrokinetic energy conversion is the fact that hydrokinetic turbine harness the kinetic energy of flowing water, and therefore doesn't require dams and additional support construction. Hydrokinetic turbines are usually much cheaper to implement and maintain.

Computer rendering of an array of hydrokinetic turbines in operation. (Image credit: Hydro Green Energy)

Hydro Green Energy's turbines have been installed below an existing hydropower plant in Hastings, Minnesota. The installed turbines have a total of 250 kW of capacity, which may not be much, but represents an important step in introducing this technology elsewhere in the US. This is the first operational hydrokinetic power plant in the US at this point. The added turbines contributed to a 5.7% increase in sustainable energy generation, but without having to expand the existing dam, or build a whole new one.

Hydro Green Energy has an ambitious plan to harness about 1600 MW of hydrokinetic energy from the Mississippi and Ohio rivers. Even though the first turbine was installed last year, the new hydrokinetic power plant had to wait to become fully operational until the results from a study about the impact on fish arrived.