GHG Protocol Corporate Standard: A Practical Guide for Enterprise Teams

The GHG Protocol Corporate Accounting and Reporting Standard has been the de facto methodology for enterprise greenhouse gas inventories since 2001. CSRD's ESRS E1 standard explicitly references it as the required methodology for EU mandatory disclosures. Yet in practice, we find that enterprise teams preparing their first CSRD filings frequently misapply or misunderstand three specific aspects of the Corporate Standard: organisational boundary setting, the rules around Scope 2 dual accounting, and base-year recalculation requirements. Getting these wrong does not just produce inaccurate figures — it produces figures that contradict each other or cannot be reconciled across reporting periods, which is what triggers auditor findings and restatements.

Organisational Boundary: Three Approaches, One Choice

Before calculating any emission figures, you must define which entities are included in your inventory. The GHG Protocol offers three approaches:

• Equity share: Include emissions proportional to your ownership stake in each entity. A 40% stake in a joint venture contributes 40% of that JV's emissions to your inventory.
• Operational control: Include all entities over which you have the authority to introduce and implement operating policies. Full 100% of those entities' emissions are included regardless of ownership percentage.
• Financial control: Include all entities consolidated in your financial accounts under IFRS or GAAP. This mirrors financial consolidation most closely and is intuitive for finance teams.

ESRS E1 does not mandate a specific approach, but it requires you to disclose which approach you use and apply it consistently. The choice matters more than it might appear. An enterprise with a joint venture in a high-emission manufacturing operation will report very different Scope 1 figures depending on whether it uses equity share (40% of JV emissions) or operational control (if it does not manage the JV's operations, it would exclude those emissions entirely under operational control).

In our experience, most enterprises that operate in integrated supply chains choose operational control because it aligns with how operational decisions are made. Enterprises with significant minority-stake financial investments tend toward equity share. The wrong answer is to choose inconsistently — reporting some entities under one approach and others under another in the same inventory.

Scope 1: Direct Emissions and What Gets Counted

Scope 1 covers direct GHG emissions from sources the company owns or controls. In practice, this means:

• Combustion of fuels in stationary sources (boilers, furnaces, process heaters) owned or controlled by the company
• Combustion of fuels in mobile sources (company-owned or -leased vehicles, forklifts, company aircraft)
• Process emissions — chemical or physical processes that release GHGs independently of combustion (calcination in cement production, for example)
• Fugitive emissions — intentional or unintentional releases from equipment (refrigerant leaks, methane from gas transmission)

The seven GHGs covered under the GHG Protocol are CO2, CH4, N2O, HFCs, PFCs, SF6, and NF3, all reported in CO2-equivalent (CO2e) using Global Warming Potential values from the IPCC. ESRS E1 requires use of the IPCC AR5 or AR6 GWP values — note that GWP values changed between AR5 and AR6, particularly for methane, and the version used must be documented.

Scope 2: Location-Based and Market-Based — Why Both Are Required

Scope 2 is where the most common methodological confusion arises in enterprise CSRD filings. The GHG Protocol Scope 2 Guidance (2015) introduced dual accounting — requiring companies to calculate and report Scope 2 under both the location-based method and the market-based method.

Method	Emission factor used	Effect of renewable energy contracts
Location-based	Average grid emission intensity for the geographic area where electricity is consumed (IEA, national grid averages)	No direct effect — reflects actual grid mix
Market-based	Emission factor from the specific contractual instrument (electricity supplier contract, Renewable Energy Certificate, Guarantee of Origin)	Reduces or eliminates Scope 2 if company holds residual-mix certificates or PPAs with zero-emission suppliers

ESRS E1 requires both figures in the disclosure. A company cannot report only market-based Scope 2 — even if it has procured 100% renewable electricity and its market-based Scope 2 is effectively zero. The location-based figure must accompany it. Auditors flag the absence of the location-based figure as a gap in the first review pass.

"The most elegant renewable electricity procurement strategy in the world does not eliminate your obligation to disclose location-based Scope 2. Both figures are mandatory. The comparison between them is actually informative — it shows how much of your apparent reduction is procurement versus actual grid decarbonisation." — Felix Gruber, Head of Climate Science, Carbonkindle

Base-Year Recalculation: When and How

The GHG Protocol Corporate Standard requires companies to establish a base year — a fixed historical reference point against which emission trends are measured. Base-year recalculation rules define when and how to update this reference point when structural changes occur.

Recalculation is required when:

1. Structural changes: Acquisitions, mergers, divestitures, or outsourcing that bring new emission sources into or remove existing sources from the inventory boundary. An acquisition completed in FY2025 adds new emissions to your FY2025 inventory; if those emissions are material (typically above 5% of base-year emissions), the base year must be recalculated to include the acquired entity as if it had always been part of the group.
2. Methodology changes: Changes to emission factors, calculation methods, or data sources that would produce materially different figures if applied to the base year. Switching from an older IPCC GWP to AR6 values, for example, requires retroactive recalculation if the difference is material.
3. Corrections of significant errors: If a prior-period emission figure contained an error that materially affects the trend data, the base year should be corrected.

The recalculation policy must be documented before the first CSRD filing. This policy defines the materiality threshold (the most common is 5% of base-year emissions), the triggering events, and the recalculation methodology. Having a policy in place before any recalculation is needed means auditors see a proactive, documented governance structure rather than an ad-hoc response to a structural change.

Six Gases, One Metric: Working With GWP Values

CO2-equivalent is the unit of the GHG Protocol. It converts emissions of the seven covered gases into a single metric using Global Warming Potential values, which express how much warming a unit of each gas causes relative to CO2 over a 100-year period.

Under IPCC AR6, the key GWP values are: CO2 = 1 (by definition), methane (CH4) = 29.8 for fossil methane and 27.0 for biogenic methane, N2O = 273, SF6 = 25,200. The AR6 methane GWPs are notably higher than in AR5 (28/34), which means organisations with significant methane exposure — natural gas systems, livestock operations, waste management — will see higher CO2e figures under AR6 than under AR5 for the same physical emissions. This is a common source of apparent-but-not-real emission increases when organisations update their GWP methodology.

Putting It Together: A Pre-Filing Checklist

Before submitting your CSRD ESRS E1 disclosure, verify these GHG Protocol fundamentals are in place:

• Organisational boundary approach documented and applied consistently to all entities
• All seven GHGs accounted for in Scope 1 (or immateriality documented for those that are zero)
• Both location-based and market-based Scope 2 figures calculated and ready to disclose
• GWP version documented (IPCC AR5 or AR6 — ESRS E1 accepts both; pick one and be consistent)
• Base-year recalculation policy drafted and board-approved
• Scope 3 category screening complete with exclusion justifications documented for omitted categories
• Emission factors version-controlled in the calculation workbook with source citations

The GHG Protocol Corporate Standard is 140+ pages of technical guidance, but the enterprise application points that matter most for CSRD compliance are these fundamentals. Getting them right in year one means your trend data will be reliable from the start — and that is the asset most valuable for demonstrating real emissions performance over time.