Power utilities, including Tokyo Electric Power Co., leaned on customer rate hikes to boost their financial performances in the first nine months of the business year as idled nuclear plants kept fuel costs high.

Tepco and the nation's five other nuclear utilities that raised electricity rates returned to profit or narrowed losses in the nine months that ended Dec. 31. Utilities that didn't raise rates, including the third-biggest, Chubu Electric Power Co., saw profits drop or remain unchanged.

The financial results, released last week, reveal rate hikes as one of the few options available to the utilities as they seek to counter spending on fossil fuels to make up for lost nuclear capacity. All of Japan's 48 functioning reactors are idled for safety checks in light of the Fukushima crisis that started in 2011.