Hokkaido Electric Power Co. has postponed the restart of a major thermal power plant — initially scheduled for Tuesday — to Wednesday, the utility said.

The firm was set to restart the No. 1 unit at the Tomato-Atsuma thermal plant Tuesday after being offline since a powerful earthquake struck Hokkaido on Sept. 6, but the prep work took more time than expected, the utility said.

The plant generated a total of 1.65 million kilowatts of electricity, which is about a half of Hokkaido's power consumption, before the magnitude 6.7 quake struck, but its three units were forced to shut following boiler damage and a fire.