Tokyo Electric Power Co. and nine other utilities emitted 13 percent more carbon dioxide after burning fossil fuels to meet higher demand and make up a shortfall from the closure of the world's biggest nuclear plant.
The 10 power generators emitted 417 million tons of carbon dioxide in the year that ended in March, compared with 369 million tons a year earlier, according to a calculation by Bloomberg News using data released by the utilities.
The continued closure of Tepco's Kashiwazaki-Kariwa reactor complex, damaged by an earthquake July 16, 2007, has thwarted efforts to increase carbon-free power generation. Utilities, which accounted for 29 percent of Japan's total carbon emissions in 2006, have pledged to cut pollution to reach national goals for reducing gases blamed for global warming.