- Activity data
- Quantity of activity that drives an emission (e.g., gal of diesel, MWh of electricity, $ spend).
- Base year
- Reference year against which trends and targets are measured. Recalculated for structural/method changes.
- CO₂e
- Carbon-dioxide equivalent — common unit derived from mass × GWP, used to aggregate gases.
- Emission factor
- Coefficient that converts activity data into emissions of a specific gas.
- EEIO
- Environmentally Extended Input-Output — sector-level factors in kg CO₂e per dollar of spend.
- eGRID
- EPA database of US grid emission rates by subregion (location-based Scope 2).
- Fugitive emissions
- Unintentional GHG releases (refrigerant leaks, methane vents, SF₆ from switchgear).
- GWP
- Global Warming Potential — radiative-forcing factor relative to CO₂ over a chosen horizon (typically 100 years).
- HHV / LHV
- Higher / lower heating value of a fuel. US factors are HHV — never mix bases.
- IMP
- Inventory Management Plan — documents roles, sources, factors, QA/QC, evidence archive.
- Location-based
- Scope 2 method using grid-average emission factors for the area where consumption occurs.
- Market-based
- Scope 2 method using contractual instruments per the Scope 2 Quality Criteria.
- REC
- Renewable Energy Certificate — tradable instrument conveying the renewable attribute of 1 MWh.
- Residual mix
- Jurisdiction-published emission factor excluding already-claimed attributes; prevents double counting.
- Scope 1
- Direct emissions from owned/controlled sources.
- Scope 2
- Indirect emissions from purchased electricity, steam, heat, cooling.
- Scope 3
- Other indirect emissions across the value chain (15 categories).
- Verification
- Independent assurance against a standard such as ISO 14064-3 (limited or reasonable assurance).