Two permanent sites and a testing ground for power-generating turbines in the Mississippi River are still in the works for Vicksburg, according to developers.

Boston-based Free Flow Power expects to send a study plan to the Federal Energy Regulatory Commission in July, its sixth such draft to reflect changes to the number of large propellers proposed to be placed in the river between Kentucky and Louisiana and results of ongoing reviews, said Jon Guidroz, director of project development.

“The pilot project will be in shallow-draft areas of the river north of Baton Rouge,” Guidroz said at the conclusion of a meeting at Vicksburg Convention Center that updated the company’s projected deadlines for a commercial license.

Full licensing is expected in late 2014 or early 2015.

The company seeks permits for turbines at 24 sites on the Lower Mississippi and 156 hydrokinetic projects nationwide. Two are situated on the river south of Davis Island, on the west side of the river but in part of Warren County. A site proposed in 2009 upriver near the Brunswick community near Eagle Lake was scrapped during subsequent analysis of sediment movement, river depths and other factors, said legal counsel Alan Topalian.

Sites on the river were chosen based on flow volume and velocity, and proximity to power transmission facilities and potential customers. At each site, turbines on pylons at the bottom of the river would spin like propellers and transmit energy to the river bank. Locations have not been named for pilot tests. They will test a turbine’s durability over a year’s time against moving debris, such as logs and ice, how it reacts to electromagnetic fields and other conditions, plans showed.

Retired Brig. Gen. Robert Crear, who chairs FFP Development LLC, a subsidiary of Free Flow, said hydropower is an emerging, albeit underrated, form of alternative energy sources.

“I call it the Rodney Dangerfield of renewals,” Crear said. “People want to talk about wind, want to talk about solar. Hydro doesn’t get the respect it deserves in terms of renewable energy resources.”

Company officials were to continue consultations with the U.S. Army Corps of Engineers this week, Guidroz said. Ideal operating depth during low river stages is 20 feet below the surface and 65 feet or deeper below during high stages, according to current plans.

Each turbine is expected to produce about 10 kilowatts of power, or about enough to power about eight average-sized homes.