The cost of the lignite portion of Mississippi Power Co.'s Kemper County energy plant went up $18 million more through the end of February, the energy provider reported Friday.
The project now stands at $6.66 billion, nearly three times the original estimated cost.
Mississippi Power said in its monthly report to the Public Service Commission it continues to make repairs and modifications to the refractory lining inside each of the gasifiers and is evaluating the need for additional refractory work.
That work could delay the projected in-service date and cost, the company said, and any changes in the schedule are expected to be part of the report in late April.
An extension of the in-service date beyond Aug. 31 would add an estimated $25 million to $35 million per month to the cost, the company said.