Seven of Japan's 10 major utilities finished their first quarter with net losses totaling nearly ¥190 billion ($1.45 billion), according to their earnings reports, as soaring fuel prices on the back of Russia's invasion of Ukraine made thermal power generation more expensive.

Tokyo Electric Power Company Holdings logged the biggest loss among the region-based utilities, as its net loss expanded to ¥67.10 billion for the three months ended June from ¥3.03 billion a year earlier, it said Tuesday.

The widened loss came as the company was forced to pay more for coal and liquefied natural gas for its fossil-based power generation, according to the utility.