Equipped with wider flow passages and fewer rotating surfaces, the new turbine will benefit the river’s fish habitat, “making it easier for fish to pass through unharmed,” the company said.

The existing Rainbow plant, which houses eight turbine-generators, will operate until the new powerhouse is completed, and then will be decommissioned.

“PPL Montana is recommitting itself to the tradition of renewable energy development that has been part of Montana’s history and the Great Falls area for more than 100 years,” said Pete Simonich, vice president and chief operating officer.