TOKYO, Oct 13 (Reuters) - Japan's biggest power generator JERA said on Tuesday it will shut down all inefficient coal-fired power plants in Japan by 2030 and it aims to achieve net zero emissions of carbon dioxide by 2050 to tackle climate change.

Closing inefficient coal power stations is in line with government policy but this was the first time a power company declared an intention to match that policy.

A government panel is deliberating on how to define an inefficient coal-fired plant but JERA said, provisionally, it saw inefficient plants as ones that use "supercritical or less" technology.

JERA, a thermal power and fuel joint venture between Tokyo Electric Power Company Holdings and Chubu Electric Power, set the ambitious 2050 target as companies worldwide are accelerating action to help create a decarbonised society.

"As a company operating globally and as a utility generating about one-third of domestic electricity, setting these goals is an essential qualification for remaining to be an energy company and an entry ticket for doing business in the global market," Hisahide Okuda, managing executive officer at JERA, told a news conference.

The company declined to say how many coal power plants will be closed by 2030, citing competitive reasons.

To achieve the 2050 target, JERA aims to boost renewable energy centered on offshore wind-power farms while using greener fuels such as ammonia and hydrogen at its thermal plants.

It plans to start a pilot programme to use ammonia as a fuel with coal in mixed combustion at its Hekinan thermal power station in central Japan by 2030 and hopes to achieve 20% use of ammonia at its coal-fired power plants by 2035.

Other measures include improving an efficiency of gas-fired power plants and burning hydrogen in mixed combustion at gas-fired power stations, it added.

JERA declined to say from where it plans to import ammonia and hydrogen.

By 2030, JERA aims to cut 20% more carbon emission intensity of thermal power plants than the government's current reduction target for those plants across the nation.

Thermal power generation using fossil fuels meets about 80% of Japan's electricity demand and accounts for about 40% of its total CO2 emissions, according to JERA. (Reporting by Yuka Obayashi Editing by Robert Birsel)