Methodology
GHG Protocol Corporate Standard: calculation methodology and emission factor sources.
The platform computes facility-level greenhouse gas (GHG) emissions following the GHG Protocol Corporate Standard (WRI/WBCSD, 2004; amended 2015) and the Scope 2 Guidance (WRI, 2015).
Stationary Combustion
EPA GHG Emission Factors Hub 2025, Table 1. CO2e = Fuel Quantity × EF + CH4/N2O components with IPCC AR6 GWP-100 (CH4: 29.8, N2O: 273).
Mobile Combustion
EPA GHG EF Hub 2025, Tables 2–5. CO2 via fuel-based, CH4/N2O via distance-based calculation.
Fugitive Emissions
IPCC AR6 WG1, Table 7.SM.7. CO2e = charge_kg × annual_leak_rate × GWP / 1,000. Default leak rates from EPA Vintaging Model.
Location-Based
EPA eGRID2023 subregion emission factors with T&D loss adjustment (4–7%).
Market-Based
Hierarchy: supplier-specific EF → REC-adjusted → residual mix → eGRID fallback.
Cat 1–2: Purchased Goods
EPA USEEIO v2.0 spend-based factors across 18 sectors.
Cat 3: Fuel & Energy
Well-to-tank + T&D loss emissions.
Cat 5: Waste
EPA EF Hub Table 12 by waste type and disposal method.
Cat 6: Business Travel
Mode-specific EFs: air (haul-distance), rail, car rental.
Cat 7: Commuting
Employee count × distance × mode EF × working days.
Analytical
95% CI via error propagation: CI = total × √Σ(relative_uncertainty²).
Monte Carlo
IPCC Tier 2: 1,000 runs, seeded PRNG (Mulberry32), normal/lognormal parameter distributions.
EPA GHG EF Hub 2025 • eGRID 2023 • IPCC AR6 GWP-100 (2021) • DEFRA/DESNZ 2025 • CBECS 2018 • ASHRAE 169-2020 • EPA USEEIO v2.0 • EIA AEO 2025
docs/methodology.md