Regulators say Mississippi Power Co. needs to submit more evidence that it has spent money prudently on the power plant it's building in Kemper County.
The state Public Service Commission voted 3-0 Tuesday to require more information from Mississippi Power on the $4.75 billion it is spending to build the coal-fueled power plant in eastern Mississippi.
The Sierra Club, which opposes the plant, had asked commissioners to reject the company's spending.
Commissioners had planned to put off reviewing spending until the Kemper plant was finished, but agreed in a settlement with Mississippi Power to examine some costs earlier. Tuesday's action sets the first hearing for May 2014.
Mississippi Power is a subsidiary of Atlanta-based Southern Co.