DOHA, Aug 31 (Reuters) - QatarEnergy will build the world's largest "blue" ammonia plant, which is expected to come online in the first quarter of 2026 and to produce 1.2 million tonnes per year, chief executive and state minister for energy Saad al-Kaabi said on Wednesday.

While conventional ammonia production emits CO2 if it is made with fossil fuel, during the production of blue ammonia any carbon dioxide generated is captured and stored.

The cost of the Ammonia-7 project is approximately $1.06 billion, according to a press release issued by QatarEnergy subsidiary, Industries Qatar. During a news conference, Kaabi had cited an incorrect figure.

The facility will capture and sequester 1.5 million tonnes of carbon dioxide a year through the manufacturing process, he added.

"We see an increasing interest in using ammonia as fuel, driven by the need to reduce CO2 emissions in the energy ecosystem," Kaabi said.

Ammonia is mainly made from hydrogen produced from natural gas and nitrogen from the air. It does not emit CO2 when burned.

It is principally used as a raw material for fertiliser and chemicals, but it can also be used as a low-carbon fuel in power stations.

Thyssenkrupp and Consolidated Contractors Company are the contractors of the project. (Reporting by Andrew Mills; Writing by Nadine Awadalla; Editing by Maha El Dahan, Jason Neely, Jan Harvey and Angus MacSwan)