Senators voted 26-13 for her confirmation on Friday -- the last day of the 2013 legislative session.
Sen. Jack Latvala took the unusual move of separating her from a list of other executive appointments.
The Clearwater Republican said he was concerned about Edgar siding too often on the side of electric companies on rate increases. Other Democrats and Republicans also expressed concerns.
Edgar was originally appointed by Gov. Jeb Bush and then reappointed by Gov. Charlie Crist before being reappointed by Gov. Rick Scott. She is the longest serving member of the panel.
The five-member commission regulates the state's investor-owned utilities.