Occidental Petroleum’s Houston-based carbon capture, utilization and, sequestration (CCUS) subsidiary, 1PointFive, has inked a six-year deal to sell 500,000 metric tons of carbon dioxide removal credits to software giant Microsoft.

In a news release, 1Point5 says this agreement represents the largest-ever single purchase of carbon credits enabled by direct air capture (DAC). DAC technology pulls CO2 from the air at any location, not just where carbon dioxide is emitted.

Under the agreement, the carbon dioxide that underlies the credits will be stored in a below-the-surface saline aquifer and won’t be used to produce oil or gas.

“A commitment of this magnitude further demonstrates how one of the world’s largest corporations is integrating scalable [DAC] into its net-zero strategy,” says Michael Avery, president and general manager of 1PointFive. “Energy demand across the technology industry is increasing, and we believe [DAC] is uniquely suited to remove residual emissions and further climate goals.”

Brian Marrs, senior director for carbon removal and energy at Microsoft, says DAC plays a key role in Microsoft’s effort to become carbon-negative by 2030.

The carbon dioxide will be stored at 1PointFive’s first industrial-scale DAC plant, being built near Odessa. The $1.3 billion Stratos project, which 1Point5 is developing through a joint venture with investment manager BlackRock, is designed to capture up to 500,000 metric tons of CO2 per year.

The facility is scheduled to open in mid-2025.

Aside from Microsoft, organizations that have agreed to buy carbon removal credits from 1Point5 include Amazon, Airbus, All Nippon Airways, the Houston Astros, the Houston Texans, and TD Bank.

Occidental says 1PointFive plans to set up more than 100 DAC facilities worldwide by 2035.