As industrial organizations commit to science-based Net Zero goals, measuring direct operational impact alone is no longer sufficient. Up to 80-90% of an enterprise's total carbon footprint lies in Scope 3 emissions—indirect greenhouse gas emissions occurring across its upstream and downstream value chain.
GHG Protocol Classification Standard
Scope 1 covers direct emissions from owned/controlled boilers, furnaces, and vehicles. Scope 2 covers purchased grid electricity, steam, heating, and cooling. Scope 3 covers 15 distinct upstream and downstream value chain categories.
1. Scope 1, 2, and 3 Comparison Matrix
| Emissions Scope | Operational Boundary | Data Source | Calculation Formula |
|---|---|---|---|
| Scope 1 (Direct) | Owned boilers, furnaces, DG sets, process reactions | Liter/Kg of fuel burned | Activity Data × Fuel Specific Emission Factor |
| Scope 2 (Indirect - Energy) | Purchased grid electricity, steam, chilled water | Utility electric bills (kWh) | Electricity kWh × Grid CEA/IEA Emission Factor |
| Scope 3 (Upstream) | Purchased raw materials, capital goods, logistics, travel | Supplier Invoices & Ton-Km freight logs | Quantity (kg/km) × Spend/LCA Emission Factor |
| Scope 3 (Downstream) | Use of sold products, processing, end-of-life disposal | Product sales volume & lifespan estimates | Units Sold × Product Lifetime Energy × Grid Factor |
2. The 15 Scope 3 Categories under GHG Protocol
Scope 3 emissions are split into 8 Upstream categories and 7 Downstream categories:
- Category 1 - Purchased Goods & Services: Cradle-to-gate emissions of raw materials and purchased components.
- Category 2 - Capital Goods: Extraction and production of machinery, buildings, and IT hardware assets.
- Category 3 - Fuel & Energy Related Activities: Well-to-tank (WTT) extraction emissions for fuels used in Scope 1 & 2.
- Category 4 - Upstream Transportation & Distribution: Inbound freight logistics paid for by the reporting company.
- Category 5 - Waste Generated in Operations: Third-party disposal and treatment of operational solid/liquid waste.
- Category 6 & 7 - Business Travel & Employee Commute: Passenger transit, flights, and remote working energy.
- Category 9 & 11 - Downstream Freight & Use of Sold Products: Outbound shipping and energy consumed during product use.
3. Step-by-Step Scope 3 Inventory Calculation Method
- Step 1 - Screen for Materiality: Identify which of the 15 categories account for >5% of total carbon footprint.
- Step 2 - Gather Activity Data: Collect primary mass/energy data (e.g., kg of steel bought) or secondary spend data ($ value spent).
- Step 3 - Apply Verified Emission Factors: Multiply activity metrics by official Ecoinvent, DEFRA, or GHG Protocol lifecycle databases.
- Step 4 - Audit Trail Verification: Submit calculations for ISO 14064-3 third-party verification.
Frequently Asked Questions (FAQ)
How do I start measuring Scope 3 if my suppliers don't provide data?
You can start using secondary spend-based or hybrid methods (EEIO - Environmentally Extended Input-Output models) and progressively transition key Tier-1 suppliers to primary activity data.
Is Scope 3 mandatory under SEBI BRSR and EU CSRD?
Yes. SEBI BRSR Core requires value chain reporting for top listed entities, and EU CSRD/ESRS E1 mandates Scope 3 disclosure if material.