Emission Estimation Methodology
How we convert your activity data to emissions estimates for your buyer's CSRD Scope 3 disclosures under ESRS E1. Full transparency for audit trails.
Regulatory Context: CSRD & ESRS E1
The EU Corporate Sustainability Reporting Directive (CSRD) requires large companies to report Scope 3 GHG emissions across their value chain under ESRS E1 (Climate Change). This includes upstream emissions from purchased goods, services, and logistics—data that must be collected from suppliers like you. This tool generates the activity data statement your buyer needs.
Enforced Audit Posture Defaults
The following constraints are non-configurable to ensure all outputs meet audit and procurement requirements without escalation:
Electricity Method
Location-based only
Allocation Method
Revenue-based only
Output Unit
Metric tonnes CO₂e only
Reporting Period
Annual totals only
Scope 3 Categories
1, 3, 4 only
Emission Factor Versions
EPA eGRID 2022, DEFRA 2024 v1.0
These constraints align with ESRS E1 guidance and eliminate ambiguity that causes procurement escalation or audit findings.
Emission Factor Sources
We use recognized, publicly-available emission factor databases. Factors are applied in the following priority order:
Climatiq API
Primary source for region-specific emission factors. Provides the most granular and up-to-date factors based on facility location (ZIP code).
climatiq.ioUS EPA Emission Factors Hub
Fallback for US-based facilities when Climatiq data is unavailable. Updated annually. Covers stationary combustion, mobile sources, and electricity.
EPA GHG Emission Factors HubUK DEFRA Conversion Factors
Used for transportation and logistics calculations. Provides well-to-tank (WTT) factors and comprehensive freight emission factors by mode.
DEFRA 2024 Conversion FactorsCalculation Logic
All calculations are deterministic. No machine learning or optimization is applied. The same inputs will always produce the same outputs.
Basic Formula
Unit Normalization
All inputs are normalized to standard units before factor application:
| Input Unit | Normalized To | Conversion |
|---|---|---|
| MWh | kWh | × 1,000 |
| therms | kWh | × 29.3 |
| ccf | therms | × 1.037 |
| liters (fuel) | gallons | ÷ 3.785 |
| km | miles | ÷ 1.609 |
Spend-Based Estimation
When only spend data is provided, we use average cost factors to estimate activity:
Spend-based estimates are automatically flagged as Low data quality in the output report. This is appropriate per GHG Protocol guidance for Scope 3 screening-level calculations.
Data Quality Tiers
Every data point in your SPADS report includes a data quality indicator. This supports your buyer's data quality assessment requirements under CSRD.
- Direct meter readings
- Utility invoices
- Fuel purchase records
- Partial year extrapolation
- Allocation-based data
- Engineering estimates
- Spend-based calculation
- Industry averages
- Proxy data
Audit Trail
Every SPADS report includes a calculation audit trail in JSON format. This provides:
- Unique Report ID tied to all calculations
- Timestamp of report generation
- Emission factor source and version for each calculation
- Step-by-step calculation breakdown
- Unit conversions applied
Regulatory Framework Reference
This methodology is designed to produce supplier activity data that supports EU buyer Scope 3 disclosures under:
- CSRD Article 29a: Corporate sustainability reporting requirements
- ESRS E1: European Sustainability Reporting Standards - Climate Change
- GHG Protocol Scope 3: Calculation method reference (not certification)
Note: This tool generates activity data statements only. It is not a CSRD report, an emissions certification, or an assurance opinion.