The explosion happened Thursday night at Plant Bowen, a coal-fired plant in Euharlee -- about 50 miles northwest of downtown Atlanta.
Georgia Power spokesman Brian Green said Friday that the utility had started looking into the accident, but does not yet know how long the investigation will take.
The explosion happened at the plant's Unit 2 generator, which converts heated steam into electricity. Green says crews were performing normal maintenance work on the generator when the explosion happened.
Officials from the U.S. Occupational Safety and Health Administration -- which investigates workplace accidents -- has started an investigation into the explosion.
Georgia Power is a subsidiary of the Atlanta-based Southern Co.