TGS Green Hydrogen will build the plant in the southern province of Ben Tre, with trial operations due to start from the first quarter of next year, the government said in a statement.
Hydrogen is categorised 'green' when it is extracted from water using electrolysis powered by renewable energy and is seen as crucial to help decarbonise industry, though the technology is still expensive and at an early stage of development.
The VND19.5 trillion ($840 million) plant will initially produce 24,000 tonnes of green hydrogen, 150,000 tonnes of ammonia and 195,000 tonnes of oxygen a year, the government said, adding that capacity would be more than doubled in a later stage.
The country made a commitment at the United Nations climate conference in Glasgow (COP26) in November last year to become carbon neutral by 2050.