Mississippi Power Co. announced Thursday that it will need more time to complete its $7 billion-plus power plant in Kemper County in order to make repairs.

And the company isn’t saying how much time is needed.

In February, Mississippi Power projected the remainder of the power plant would be placed in service by mid-March 2017. On March 9, Mississippi Power discovered tube leaks in one of the plant’s syngas, or synthesis gas, coolers affecting one of the plant’s gasifiers.

Mississippi Power, a unit of Atlanta-based Southern Co., revealed the setback in a U.S. Securities and Exchange Commission filing Thursday. This is the latest in a series of missed projected deadlines.

An updated completion schedule and cost estimate for the plant should be revealed in a monthly status report that Mississippi Power expects to file by early April.

The plant, which is running on natural gas, was supposed to go into full operation running on syngas by May 2014.

As in previous filings, Mississippi Power estimates that missing this latest deadline would cost about $25 million to $35 million per month. Additional costs also may be required if any further equipment or design issues emerge, the utility says.

As for what the public pays, there currently is a $2.88 billion cap for Mississippi Power customers. Any increase beyond that depends on Mississippi Public Service Commission approval, once the company submits its new rate case to the commission on June 3.