"Greenhouse gases" or "GHGs" means the air pollutant defined in 40 CFR 86.1818-12(a) as the aggregate group of six greenhouse gases: CO2, nitrous oxide, methane, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride. To represent an amount of GHGs emitted, the term "tpy CO2 equivalent emissions (CO2e)" shall be used. CO2e is computed as follows:
Ill. Admin. Code tit. 35, § 204.430