How to Answer a Supplier Carbon Questionnaire in Under an Hour

What Is a Supplier Carbon Questionnaire?

A supplier carbon questionnaire is a form sent by a large enterprise to its suppliers requesting verified greenhouse gas (GHG) emissions data. These questionnaires exist because the EU's CSRD regulation requires large companies to disclose their full Scope 3 emissions — which means measuring the carbon footprint of every significant supplier.

If you supply goods or services to any company with 250+ employees and €40M+ in annual turnover, you should expect to receive one. Many suppliers have already received several.

Which Companies Are Sending These Questionnaires?

Enterprise clients currently issuing carbon questionnaires include large German manufacturers (automotive, machinery, chemicals), retail chains and FMCG brands, construction and infrastructure firms, financial services companies, and public sector procurement bodies — especially in Scandinavia, Germany, and the Netherlands. Most questionnaires arrive through platforms like SAP Ariba, Coupa, or Jaggaer, or directly by email from a procurement manager.

What Data Do You Actually Need?

The core data requested on 90% of supplier carbon questionnaires:

• Scope 1 total (tCO2e) — direct combustion: gas, diesel, petrol, LPG, and refrigerant leaks
• Scope 2 total (tCO2e) — purchased electricity, location-based or market-based
• Scope 3 total (tCO2e) — business travel, employee commuting, waste, upstream fuel extraction
• Emissions intensity — tCO2e per employee, or per €1 million revenue
• Reporting year — the most recent complete calendar year
• Methodology — which standard you followed (GHG Protocol Corporate Standard is the answer)
• Verification level — self-assessed, third-party reviewed, or externally audited

Where Do You Find the Raw Data?

Your emissions data comes from records you already hold:

• Scope 1 — Natural gas: your annual gas bills (look for m³ or kWh figures)
• Scope 1 — Diesel/petrol: fuel card statements or vehicle expense receipts
• Scope 1 — Refrigerants: engineering maintenance records showing refrigerant top-up quantities
• Scope 2 — Electricity: electricity invoices for the full year, in kWh
• Scope 3 — Business travel: booking records or expense reports
• Scope 3 — Waste: your waste contractor's annual tonnage report
• Scope 3 — Commuting: headcount multiplied by estimated average commute

Exact figures are not always required. Reasonable estimates are accepted as long as you state your methodology clearly.

How Do You Convert Utility Bills into tCO2e?

This is where most suppliers get stuck. You cannot report raw kWh or litres — you must convert to tonnes of CO2 equivalent using published emission factors. The standard European source is DEFRA 2023.

For example: a German office using 50,000 kWh/year: 50,000 × 0.364 ÷ 1,000 = 18.2 tCO2e from electricity alone. DeCarbonOPS applies these factors automatically — you enter raw utility figures, and it outputs tCO2e for each scope.

What Happens If You Don't Respond?

Procurement teams mark non-responding suppliers as high-risk. In practice:

• Your supplier score in SAP Ariba or Coupa drops, reducing visibility in future tender processes
• Repeat non-responses can trigger a formal review and removal from the approved vendor list
• Enterprise clients with hard reporting deadlines cannot include your data in their CSRD filings, making you a liability
• Competitors who do respond gain a measurable advantage in supplier qualification

What Is the Fastest Way to Complete Your First Questionnaire?

Generate a Carbon Passport using DeCarbonOPS. It calculates your Scope 1, 2, and 3 emissions from your utility inputs, applies DEFRA 2023 factors, and produces a shareable verification URL in under 20 minutes. That URL is what you paste into the questionnaire portal — it satisfies the data request for most enterprise systems including SAP Ariba and Coupa.