Japan’s biggest utility and the owner of the wrecked Fukushima nuclear power plant said it needs atomic energy to meet its pledge to cut its carbon dioxide emissions in half by 2030.

It will take time to boost capacity of renewable energy, such as offshore wind, which makes nuclear energy indispensable for the company to curb CO2 emissions 50% by fiscal 2030 from 2013 levels, according to Tokyo Electric Power Company Holdings Inc. President Tomoaki Kobayakawa. All of its nuclear reactors were either crippled or shut shortly after the March 2011 earthquake and tsunami, which triggered meltdowns at the Fukushima No. 1 plant.

"Utilizing a certain amount of nuclear will be necessary for Japan to become carbon neutral,” Kobayakawa said in an interview with Bloomberg on Thursday.