• Horizon 1 uses direct-to-chip liquid cooling and NVIDIA GB300 NVL72 systems, with the deployment receiving NVIDIA Exemplar Cloud status
  • Three more 50MW buildings are scheduled for Microsoft in 2026 under IREN's five-year, $9.7bn cloud-services contract

The fact

IREN said Microsoft has accepted Horizon 1, a 50MW IT-load AI-cloud building at the company's Childress campus in Texas. The direct-to-chip liquid-cooled facility is the first of four 50MW deployments scheduled for Microsoft during 2026 under a five-year cloud-services contract valued at about $9.7bn.

NVIDIA tested IREN's GB300 NVL72 deployment at Horizon 1 and awarded it Exemplar Cloud status. When the Microsoft agreement was announced in November 2025, IREN said the four phases would collectively provide 200MW of critical IT load and that Microsoft would provide a 20% prepayment. IREN, formerly known as Iris Energy, has been expanding its AI-cloud business while winding down Bitcoin mining operations. Horizons 2, 3 and 4 remain scheduled for delivery later in 2026.

The assessment

Microsoft's acceptance narrows the execution question for IREN. The company no longer needs to show only that the Horizon design can be built; it now has to reproduce the handover sequence across another 150MW within the same year. For this rollout, physical completion is only one milestone. Power, liquid cooling, GPU systems and network infrastructure must be ready together before each building can reach customer acceptance. IREN has not disclosed when Horizon 1 begins contributing to reported revenue, so acceptance should not be treated as a revenue-recognition date.

For BTW readers, IREN's near-term performance now depends on repeatability rather than first-build proof. Horizons 2-4 must pass through commissioning and acceptance for the full 200MW Microsoft deployment to be delivered in 2026. A widening interval between construction completion and customer acceptance would identify pressure in the deployment chain, while a steady sequence of accepted buildings would show that IREN can repeat the Horizon 1 delivery process across the Childress programme.

What to watch

Watch the acceptance dates for Horizons 2, 3 and 4 and whether IREN reports the full 200MW Microsoft deployment delivered in 2026. Disclosures on installed GPUs, commissioning milestones and revenue contribution will help distinguish completed buildings from capacity handed to the customer. IREN's FY26 results, due on 27 August, may also clarify spending and revenue timing around Horizon 1.