Methodology Library

Public documentation of our emission factor sources, calculation methods, and standards alignment. Every number in OffGridFlow is traceable to these sources.

Standards Alignment

GHG Protocol Corporate StandardAligned
Scope 1 & 2 accounting and reporting
GHG Protocol Scope 2 GuidanceAligned
Dual reporting (location + market-based)
GHG Protocol Scope 3 StandardAligned
Value chain accounting, 15 categories
IFRS S2 (ISSB)Mapped
Climate-related financial disclosures
ESRS E1 (CSRD)Mapped
EU sustainability reporting standard
California SB 253Ready
State-level Scope 1/2/3 reporting

Emission Factor Sources

OffGridFlow uses 184 verified emission factors from the following authoritative sources. All factors include provenance metadata (source, region, validity period, methodology).

EPA eGRID 2023
US EPA Emissions & Generation Resource Integrated Database. Location-based grid emission factors by eGRID subregion.
Scope 227 US subregions
IEA 2023
International Energy Agency country-level grid emission factors for location-based Scope 2 accounting.
Scope 255+ countries
UK DEFRA 2024
UK Department for Environment, Food & Rural Affairs conversion factors for stationary combustion, mobile sources, refrigerants, and value chain activities.
Scope 1, 2, 3Global
IPCC AR6 GWP-100
IPCC Sixth Assessment Report Global Warming Potential values for refrigerants and fugitive gases (100-year time horizon).
Scope 1Global
GHG Protocol Guidance
Category-level default factors and methodology guidance from the GHG Protocol Corporate Value Chain Standard.
Scope 3Global

Calculation Methods

Location-Based (Scope 2)
GHG Protocol Scope 2 Guidance
Uses average grid emission factors for the region where electricity is consumed. Reflects the average emissions intensity of the local grid.
Market-Based (Scope 2)
GHG Protocol Scope 2 Guidance
Uses supplier-specific or contractual instrument factors. Reflects purchasing decisions including RECs, PPAs, and green tariffs.
Activity-Based (Scope 1)
GHG Protocol Corporate Standard
Calculates emissions from direct measurement of fuel consumed, distance traveled, or refrigerant leaked, multiplied by fuel-specific emission factors.
Spend-Based (Scope 3)
GHG Protocol Scope 3 Standard
Estimates emissions using economic input-output (EEIO) factors applied to procurement spend data. Used when activity data is unavailable.
Supplier-Specific (Scope 3)
GHG Protocol Scope 3 Standard
Uses primary data from suppliers for purchased goods and services. Highest accuracy tier for Scope 3 Category 1.

Calculation Transparency

Every emission calculation in OffGridFlow is recorded in an immutable calculation ledger with the following fields:

✓Activity quantity and unit
✓Emission factor ID and value
✓Factor source and region
✓Calculation method used
✓Human-readable formula
✓Result in kg CO2e and tonnes CO2e
✓Reporting period (start/end)
✓Timestamp and user who triggered
✓Lock status (immutable after approval)

Worked Example: Scope 2 Calculation

This example shows how a single activity flows through the calculation engine, including factor selection, formula application, ledger recording, and data quality labeling.

Step 1: Input Activity

Source: CSV upload
Type: Electricity
Scope: 2 (purchased energy)
Location: US-WEST (WECC region)
Quantity: 10,000 kWh
Period: Jan 1 — Jan 31, 2026
Data quality: Measured
Status: Draft

Step 2: Factor Selection

Factor ID: grid-us-west
Source: EPA eGRID 2023 (WECC)
Value: 0.298 kg CO2e / kWh
Method: Location-based
Year: 2023
Uncertainty: +/- 5%

Step 3: Calculation

emissions = quantity x factor
emissions = 10,000 kWh x 0.298 kg CO2e/kWh
emissions = 2,980.00 kg CO2e = 2.98 tonnes CO2e

Step 4: Immutable Ledger Record

This record is created in the calculation ledger and cannot be modified after creation.

ledger_idcalc-2026-01-abc123
activity_idact-electricity-jan2026
scope2
quantity10,000
unitkWh
factor_idgrid-us-west
factor_value0.298 kg CO2e/kWh
factor_sourceEPA eGRID 2023 (WECC)
factor_regionUS-WEST
methodlocation-based
formula10000 * 0.298 = 2980.00 kg CO2e
result_kg_co2e2,980.00
result_tonnes_co2e2.98
data_qualitymeasured
calculated_byoperator@company.com
calculated_at2026-02-03T14:22:00Z
is_lockedfalse (draft)
version1

Step 5: Approval & Lock

Submittedby operator@company.com at 2026-02-03T14:30:00Z
Reviewedby manager@company.com at 2026-02-04T09:15:00Z — "Verified against utility invoice"
Approvedby cfo@company.com at 2026-02-04T11:00:00Z
Lockedis_locked = true. Record is now immutable. Factor snapshot locked to Q1 2026.

Step 6: Export & Reconciliation

When a compliance report is exported, the system records scope totals and a SHA256 checksum. Reconciliation verifies the export matches current data.

Report: SEC Climate Disclosure 2026
Format: PDF
Scope 2 at export: 2.98 tCO2e
Checksum: a7f3c2...
Exported by: cfo@company.com
Reconciliation: Match (0% drift)

Known Limitations

  • !Scope 3 spend-based factors use EEIO coefficients which are sector averages, not company-specific. Accuracy improves with supplier-specific data.
  • !Market-based Scope 2 requires user-supplied contractual instrument data. OffGridFlow does not verify REC/PPA authenticity.
  • !Grid emission factors are updated annually. Mid-year changes in grid mix are not reflected until the next factor update cycle.
  • !Process emissions (industrial) are supported at factor level but require manual activity data input — no automated process monitoring integration.

Framework Pages Using This Methodology

These pages apply the same published calculation basis to specific reporting programs and buyer roles.

SB 253 reporting softwareCSRD reporting softwareIFRS S2 reporting softwareScope 1, 2, 3 reporting softwareCarbon accounting for finance teamsAudit-ready carbon accounting
Redacted Evidence Pack|Operations Proof|Security & Trust Center|About OffGridFlow