March 11 will mark the 10th anniversary of the Fukushima nuclear disaster, but Japan is still heavily reliant on liquefied natural gas (LNG) and coal, with only four nuclear reactors operating, down from about 50 before the disaster.

The public is still wary of nuclear power after the 2011 earthquake and tsunami caused explosions and meltdowns at the Fukushima Daiichi nuclear station, highlighting major failings in oversight and operations in the sector.

"Scientifically, we may have a breakthrough in storage battery technology that may enable renewable power to meet the entire electricity demand by 2050," Kazuhiro Ikebe, the chairman of Japan's federation of electric utilities told a news conference.

"But realistically, we will need to stretch all of the three power sources - renewable with storage battery, thermal with carbon capture storage or utilisation and nuclear power - as much as possible to meet larger power demand in 2050," he said.

Asked whether utilities want to build new nuclear power plants or extend operation periods of existing power stations, Ikebe, also president of Kyushu Electric Power, said it was too early to discuss such an issue.

"In terms of public opinion, we are not yet at the stage to talk about building new power plants or replacing existing plants," he said.

"What we need to do is to keep operating existing nuclear reactors safely and stably, so that we can regain trust from the public," he said.

(Reporting by Yuka Obayashi; Editing by Raju Gopalakrishnan)