The production facility aims to produce up to 1 billion cubic feet per day of low-carbon hydrogen, with around 98% of carbon dioxide removed, they said in a statement, without disclosing a value for the investment.
The project is part of Exxon's efforts to create a new business to make money out of cutting greenhouse gas emissions by other companies looking to decarbonise their own operations.
ADNOC Executive Vice President of Low Carbon Solutions and Business Development Michele Fiorentino told Reuters that the output will be used to supply "either the refining system of Exxon Mobil or third party buyers of blue hydrogen connected to the pipeline network in the Gulf coast".
Alternatively, Fiorentino said, it could produce blue ammonia, which will be used to supply either Northeast Asia or Europe, which are the two main demand centres.
A final investment decision on the project is expected around mid-2025 or in the second half of next year, he said.
First production is expected in 2029 and will likely ramp up to full capacity within 12 months, subject to demand, he added.
ADNOC is "reasonably confident the demand will be there," Fiorentino said, adding that the scale of the project will make its hydrogen among the most cost-competitive.
He declined to disclose the project's costs, but indicated it would be in the billions of dollars.
A second train of the same size could be added "if it made sense at that point in time," Fiorentino added.
