Tokyo Electric Power Company says electricity will be restored to Chiba City and other areas mainly in the northern part of Chiba Prefecture on Thursday.
The prefecture suffered widespread power outages after Typhoon Faxai made landfall near Tokyo early Monday.
TEPCO said on Thursday morning that the cities of Chiba, Yachiyo, Yotsukaido and Inzai will have power restored by the end of the day. Parts of Ichihara City will also have lights back on. But other areas will have to wait until Friday or later.
The utility attributes the delay in restoration work to the need to cut and remove fallen trees to bring in large vehicles for repairs. It also cites significant damage to power lines.
TEPCO has admitted it was overly optimistic about evaluating the level of damage to the power grid with the typhoon's passage.
About 339,800 households in Chiba Prefecture were without power as of 9:40 a.m. Thursday.
TEPCO says 11,000 personnel, including those from other power companies, are working to restore electricity.