The utility said in a press release it is the first time in nearly 30 years it has requested a raise in the base cost of its electric rates.
Duke Energy says it needs the increase to pay for investments the utility has made in cleaner energy sources, like four solar energy sites in South Carolina and North Carolina.
The utility says a new natural gas generation plant has allowed Duke Energy to reduce its fuel charge for customers by $16 million. That cuts the effective rate increase to closer to 12 percent.
The company serves customers in South Carolina's northeast corner.