Revenue Ruling 2021-13  explains: (1) that an acid gas removal unit at an industrial  facility is a component of carbon capture equipment within the meaning of § 1.45Q-2(c); (2) an investor in certain components of carbon capture equipment at an industrial facility is not required to own every component of carbon capture equipment within a single process train at an industrial facility to be the person to whom the section 45Q credit is attributable under § 1.45Q-1(h), but must own at least one component of carbon capture equipment in the single process train of carbon capture equipment at the industrial facility; (3) solely for purposes of section 45Q(a), the original placed-in-service date of a single process train of carbon capture equipment at an industrial facility that includes the existing acid gas removal unit and new components of carbon capture equipment is the date that the single process train is placed in a condition or state of readiness and availability for the capture, processing, and preparation of carbon oxide for transport for disposal, injection, or utilization; and (4) the original placed-in-service date of the single process train for purposes of section 45Q has no effect on the placed-in-service date of the existing acid gas removal unit for depreciation purposes under sections 167 and 168.

Revenue Ruling 2021-13 will be in IRB:  2021-30, dated July 2021.