JERA's Hekinan thermal power station will now begin demonstrating the technology, burning 20% ammonia and 80% coal at its 1-gigawatt No.4 unit, in the financial year beginning April 2023.

Burners, a tank and pipes had been installed earlier than planned, the two companies said in a statement. JERA is Japan's largest electricity generator.

The project, which started last year with small volumes of ammonia at another unit at Hekinan, is aimed at cutting carbon dioxide (CO2) emissions by using cleaner fuels.

It will be the world's first trial in which a large amount of ammonia will be used with coal at a large commercial plant. Burning ammonia emits no CO2. Other energy sources are needed to make it, but they can be renewable.

Using the technology, Japan hopes to extend the lives of its coal-fired power plants, thereby achieving both stable energy supply and lower CO2 emissions.

The country is the world's fifth-largest CO2 emitter.

Ministers from the Group of Seven countries agreed last week to largely decarbonise their power sectors by 2035.

Ammonia is traditionally used for fertiliser and industrial materials.

JERA is a joint venture between Tokyo Electric Power and Chubu Electric Power. IHI makes burners and other industrial machinery.

(Reporting by Yuka Obayashi; Editing by Bradley Perrett)