Saudi oil giant Aramco has launched a pilot direct air capture unit able to remove 12 tons of carbon dioxide per year from the atmosphere, it said on Thursday.

The facility, developed with Siemens Energy, is Saudi Arabia's first carbon dioxide direct air capture (DAC) unit and will be used to test CO2 capture materials, Aramco said.

Critics of capturing CO2 emissions have said the technology is expensive and unproven at scale.

"The test facility launched by Aramco is a key step in our efforts to scale up viable DAC systems, for deployment in the Kingdom of Saudi Arabia and beyond," Ali A. Al-Meshari, Aramco senior vice president of technology oversight and coordination, said in Aramco's statement.

"In addition to helping address emissions, the CO2 extracted through this process can in turn be used to produce more sustainable chemicals and fuels."

Aramco, the world's top oil exporter, aims to reduce its so-called Scope 1 and 2 emissions to net zero by 2050.

Aramco announced the pilot DAC unit with Siemens Energy in October 2023 and said at the time it would be completed in 2024 and was intended to pave the way for a larger pilot plant that would have the capacity to capture 1,250 tons of CO2 per year.

The state oil giant in December signed an agreement with oil services firms SLB and Linde to build a carbon capture and storage project in Jubail, Saudi Arabia. The first phase is expected to be completed by the end of 2027, capturing and storing up to 9 million tons of CO2 a year.

Aramco has signed several other agreements to explore carbon capture development and last year took part in an $80 million funding round of Los Angeles-based CarbonCapture.