1. Mandatory Dual Reporting Architecture
Since the publication of the WRI/WBCSD GHG Protocol Scope 2 Guidance (2015), any organization operating in a grid region that supports contractual instruments must report two complete, parallel Scope 2 electricity totals:
- Location-Based Scope 2: Quantifies physical grid average emissions intensity within a defined grid distribution boundary (such as US EPA eGRID subregions, national UK DESNZ grid averages, or Dubai DEWA / Abu Dhabi EWEC grid systems). Contractual instruments cannot be deducted from the location-based total.
- Market-Based Scope 2: Quantifies emissions from electricity purposefully chosen by the reporting entity through contractual Energy Attribute Certificates (EACs), Power Purchase Agreements (PPAs), supplier-specific emission rates, or—where no contractual claim is held—the Residual Mix factor.
2. The Eight Scope 2 Quality Criteria & Market Boundaries
External assurance providers under ISSA 5000 and ISAE 3410 test every zero-emission market-based claim against the eight mandatory Scope 2 Quality Criteria (Chapter 7 of the Scope 2 Guidance):
- Conveyance of Direct GHG Emission Rate Attribute: The certificate must carry the explicit contractual right to claim the generation technology's emission rate.
- Exclusive Claim (Retirement / Cancellation): The EAC must be retired in an auditable tracking registry (e.g., M-RETS, PJM GATS, AIB EECS, or the Evident I-REC Registry) on behalf of the reporting entity.
- Vintage Alignment: Generation timestamps must align as closely as practical to the consumption reporting period.
- Geographic & Market Boundary Alignment: Certificates must be sourced from the same market boundary in which the electricity consumption occurs.
| Regional Market Boundary | Eligible Contractual Instrument | Primary Registry / Residual Mix Authority | Cross-Border Redemption Rule |
|---|---|---|---|
| United States & Canada | Renewable Energy Certificates (RECs) | M-RETS, WREGIS, PJM GATS, NEPOOL GIS / Green-e Residual Mix | Allowed across US/Canada interconnected market per Scope 2 Guidance |
| European Single Market (EU/EEA) | Guarantees of Origin (GOs) under RED III (Directive 2023/2413) | Association of Issuing Bodies (AIB) EECS / AIB European Residual Mix | Permitted across AIB member states connected to the EU internal market |
| United Kingdom | Renewable Energy Guarantees of Origin (REGOs) | Ofgem REGO Register / UK Fuel Mix Disclosure Residual | UK-generated REGOs required for UK facility market-based claims |
| United Arab Emirates | International RECs (I-RECs) | I-TRACK Foundation / Evident Registry (MoCCAE / EWEC / DEWA) | Single-country UAE boundary; foreign EACs invalid for UAE facilities |
3. Market-Based Emission Factor Hierarchy & Residual Mix Math
When a facility's annual electricity consumption ($Q_{\text{total}}$) is only partially matched by retired EACs ($Q_{\text{EAC}}$), the uncovered load must be multiplied by the regional Residual Mix emission factor ($EF_{\text{residual}}$), which strips out tracked renewable attributes to prevent double counting across the grid:
Only when an official regional residual mix factor does not exist may an organization fall back to the location-based grid average factor for its uncovered market-based consumption, and this fallback must be explicitly disclosed in the inventory methodology note.
Geographic & Regulatory Applicability (UK / EU / US / UAE): Dual Scope 2 reporting is mandatory under EU CSRD (ESRS E1-6 §49) and GRI 305-2, while IFRS S2 (§29(a)(v)) requires location-based Scope 2 alongside contractual instrument disclosures. Screen UK DESNZ, US EPA eGRID, and UAE DEWA/EWEC location-based electricity baselines directly in our Corporate GHG Screening Calculator per Methodology v1.0.0, or compare multi-region Scope 2 engines in the Carbon Accounting Software Directory.