The Boston company that wants to install power-generating turbines in the Mississippi River, including near Vicksburg, has asked for an extension of permits to study the feasibility of such a hydropower plant near Concordia Parish, La.

The application with the Federal Energy Regulatory Commission was filed this week.

Daniel Lissner with Free Flow Power said the application is essentially for the extension of previous permits the company has been granted.

The company has been in the process of studying the site, which it calls the St. Catherine Bend hydrokinetic project, for some time.

Free Flow Power seeks permits for multiple hydrokinetic projects nationwide, including 24 sites on the Lower Mississippi between Kentucky and Louisiana.

Two are near Vicksburg, both south of Davis Island on the west side of the river, according to maps shown during a public hearing in March in Vicksburg.

Retired Brig. Gen. Robert Crear of Vicksburg, a former head of the Mississippi Valley Division of the U.S. Army Corps of Engineers, is an adviser to Free Flow on its projects.

The feasibility study would determine if up to 6,382 underwater power-generating turbines could be installed on the bottom of the river. The study will also consider the feasibility of infrastructure like transmission lines.

It’s part of a wider initiative which the company is investigating.

If the project moves forward, the turbines would most likely be configured on pilings mounted on the river bottom below the navigable river channel, Lissner said.

“We have also investigated the deployment of turbines suspended from barges, but have moved away from that conceptual alternative in favor of a piling-based approach to avoid impacts with navigation that would occur on the surface of the water,” he said.

The Mississippi River serves as an ideal hydrokinetic resource because of its size, flow and the maintenance protocols that keep it in its existing channels, and Lissner said the St. Catherine bend is a site of study because river bends are particularly optimal locations for turbines.

“The water accelerates around the bends, and bends tend to be deeper, so that makes for a location that you could conceivably sit more turbines mounted below the navigable channel than you could in other locations,” he said.

Lissner said the application the company has filed is for a three-year permit, and if it is granted, the company anticipates filing for a license with the FERC for the location.