Symphony Hydro has reapplied for federal permission to generate hydroelectricity in the St. Anthony Falls lock after a federal regulator last month denied its initial try.

The firm submitted its plan for twin turbine-generators in the Upper St. Anthony lock that would roll up on tracks like a garage door when the lock is needed for flood control.

The Federal Energy Regulatory Commission (FERC) on Feb. 5 denied a preliminary permit application by Symphony to install the generating equipment in the lock. It cited opposition from the U.S. Army Corps of Engineers, which owns and operates the lock. The lock will close to watercraft after June 10 under a congressional mandate intended to halt the spread of invasive carp up the Mississippi River.

The corps will still operate the locks for flood control, opening gates during high-flow periods.  The corps earlier expressed concern that the ice and debris would damage the compact and lightweight generating equipment. The latest proposal from Symphony, which lists a Raleigh, N.C. address, is more explicit in describing how the framework holding the turbine-generator would roll up above the lock. 

Symphony said in its application that it met with corps representatives last month to discuss how the power generating equipment could be operated without interfering with corps operations.The corps said it won't formally comment until FERC accepts Symphony's application. 

"I believe they are making an effort to address the concerns the Corps' had with their previous proposal," said Nanette Bischoff, the lead corps person for permitting matters in its St. Paul district, in an e-mail.

Symphony is one of three firms seeking FERC approval to produce power at  the upper falls. Xcel Energy long has operated a larger hydropower generator there.  Symphony and Crown Hydro each has proposed generating up to 3.4 megawatts when they can draw 1,000 cubic feet per second of water at the falls But park and other advocates have opposed diverting enough water to affect the appearance of the falls, and it's unlikely both would win approval. A much-smaller proposal would generate power on the river's eastern shore in the bowels of a housing development that is renovating the historic Pillsbury's milling complex. 

Symphony said in its latest application that if there's not enough water to go around and the Crown proposal advances, it would stand aside.  Crown is fighting to keep the license that the Federal Energy Regulatory Commission (FERC) granted it in 1999, after unsuccessful efforts to win local approval. It wants to amend its plans to install generators in tunnels just outside the lock on Corps of Engineers property.