Q857. What hydrogen production process units must report under subpart P starting RY2025?

A857. Starting in reporting year 2025, the hydrogen production source category includes all hydrogen production units, including captive hydrogen production units, that produce hydrogen by reforming, gasification, oxidation, reaction, or other transformations of feedstocks at a facility that emits 25,000 metric tons CO2e or more per year in combined emissions from all source categories must be reported under subpart P, except for specifically exempted units for which the emissions are reported under other subparts in 40 CFR part 98, as follows.

• Hydrogen production process units located at ammonia production plants for which emissions are reported under subpart G are not required to be reported under subpart P.
• “Catalytic reforming units” located at petroleum refineries that produce hydrogen as a byproduct during the transformation of naphtha into higher octane aromatics for which emissions are reported under subpart Y are not required to be reported under subpart P. Emissions from all other hydrogen production process units located at petroleum refineries must be reported under subpart P.
• Petrochemical process units that may produce hydrogen as part of the petrochemical production process (e.g., methanol production) for which emissions are reported under subpart X are not required to be reported under subpart P.

Process units that only separate out diatomic hydrogen from a gaseous mixture, and that do not result in additional diatomic hydrogen created by transformation of one or more feedstocks, are not considered hydrogen production process units and are not required to be reported under subpart P.