A group of environmental organizations are taking the Tennessee Valley Authority to court over its plans to renovate its Gallatin coal power plant. The coalition says TVA officials haven't justified why they plan to pile more than $1 billion into a retrofit project.

A coalition including the Sierra Club charges TVA is legally obliged to either cut the Gallatin plant’s emissions by 2017, or close it altogether. But they say in choosing costly renovations, TVA didn’t do enough to explain its rationale.

Aspen Dental will open a practice in Gallatin on Feb. 21.

Located at 1007 Nashville Pike, the practice will provide services ranging from dentures and preventive care to general dentistry and restoration and be overseen by Dr. Jeffrey Mathews.

Aspen Dental operates 380 practices in communities across 25 U.S. states. In 2012, the company’s practices recorded more than 2.5 million patient visits and welcomed more than 550,000 new patients. In the Nashville area, the company operates in Lebanon, Madison and Smyrna.

Various environmental advocacy groups — included the Nashville-based Tennessee Environmental Council —  are preparing to sue the Tennessee Valley Authority in federal court, alleging the utilty will replace an endangered fish nursery in Gallatin with a pollution control facility.

The Knoxville News Sentinel has more here.