Scope 3 Emissions
Scope 3 typically represents 70–90 % of an organisation's total carbon footprint. AlchemOS Positive supports all 15 Scope 3 categories defined in the GHG Protocol Corporate Value Chain (Scope 3) Standard.
The 15 categories
Upstream (Categories 1–8)
| # | Category | Examples |
|---|---|---|
| 1 | Purchased goods and services | Raw materials, contracted services |
| 2 | Capital goods | Manufacturing equipment, buildings |
| 3 | Fuel-and-energy-related activities | Well-to-tank for fuel, T&D losses |
| 4 | Upstream transportation and distribution | Supplier deliveries to your facilities |
| 5 | Waste generated in operations | Landfill, recycling, treatment |
| 6 | Business travel | Flights, rail, hotel stays |
| 7 | Employee commuting | Car, public transport, cycling |
| 8 | Upstream leased assets | Leased offices / vehicles (lessor's emissions) |
Downstream (Categories 9–15)
| # | Category | Examples |
|---|---|---|
| 9 | Downstream transportation and distribution | Deliveries to customers |
| 10 | Processing of sold products | Intermediate processing by customers |
| 11 | Use of sold products | Energy consumed by products in use |
| 12 | End-of-life treatment of sold products | Disposal, recycling |
| 13 | Downstream leased assets | Properties / equipment leased to others |
| 14 | Franchises | Franchisee operations |
| 15 | Investments | Portfolio emissions |
Measurement approaches
AlchemOS Positive supports all three GHG Protocol approaches for Scope 3:
Spend-based
Multiply supplier spend (£ / $) by an industry-average emission intensity factor (EEIO database). Best when activity data is unavailable.
Activity-based
Use actual quantities: tonnes of goods purchased, km travelled, kWh used. More accurate; required for Category 6 (business travel).
Supplier-specific
Use factors provided directly by your suppliers in AlchemOS Positive's Supplier Portal or via the API. Highest accuracy, recommended for Category 1 material suppliers.
Entering Scope 3 data
- Go to Carbon Tracking → New Entry
- Select Scope 3 and choose the category number
- Select your measurement approach
- Enter activity data or spend data
- Review the auto-selected emission factor and computed tCO₂e
- Save
Supplier engagement
For Category 1 (purchased goods), invite suppliers to submit their own product-level emission data:
- Settings → Suppliers → Invite Supplier
- Enter the supplier's email address
- They receive a secure link to a simplified data-submission portal
- Submitted data flows into your Scope 3 Category 1 entries automatically
Track engagement status (invited / responded / overdue) under Settings → Suppliers.
Screening and prioritisation
Use the Scope 3 Materiality Screen tool (Carbon Tracking → Scope 3 → Screen) to identify which categories are most significant for your organisation before investing in detailed data collection.
The tool uses industry benchmarks to estimate each category's likely proportion of your total footprint and flags those above a 1 % materiality threshold.
Reporting requirements
| Framework | Scope 3 required |
|---|---|
| GHG Protocol Corporate Standard | Categories deemed material |
| CDP (Carbon Disclosure Project) | All 15 categories (disclose N/A if not applicable) |
| SBTi Net-Zero Standard | Scope 3 if >40 % of total footprint |
| TCFD | Significant Scope 3 sources |
| CSRD / ESRS E1 | Full disclosure; limited assurance from 2026 |