How to Do Carbon Reporting Without Hiring a Sustainability Consultant
The Consultant Myth
Search for "carbon reporting for businesses" and the top results are mostly consultancy firms offering GHG inventory services at prices ranging from €2,000 to €15,000. This creates the impression that accurate carbon reporting requires external expertise.
It does not — at least not for the standard operational GHG inventory that procurement questionnaires ask for.
The GHG Protocol Corporate Standard, the framework that governs all supplier carbon questionnaires, is designed to be self-administered. DEFRA publishes the emission factors for free every year. The calculations themselves are arithmetic — multiply consumption by a factor, divide by 1,000. A sustainability consultant adds value in complex scenarios (lifecycle assessment, financial institution disclosures, CDP Gold-level reporting) but is unnecessary for the standard SME supplier use case.
What a Sustainability Consultant Would Do — And What You Can Do Instead
| Consultant task | What they actually do | What you can do |
|---|---|---|
| GHG boundary setting | Define which sites and activities are in scope | Follow GHG Protocol operational control principle: all activities you control are in scope |
| Data collection | Request utility bills and fuel records from you | Gather your own bills — it takes 15 minutes |
| Emission factor selection | Apply DEFRA 2023 factors to your consumption data | Use DeCarbonOPS — factors are built in |
| Scope 3 estimation | Apply standard travel and commuting factors | Enter headcount + estimates into DeCarbonOPS |
| Report writing | Format figures into a PDF report | Carbon Passport is generated automatically |
| Methodology statement | Write a paragraph describing the approach | Copy the standard statement (see below) |
The one area where a consultant genuinely adds value is complex Scope 3 Category 1 (lifecycle emissions of purchased goods) — but that is not what most procurement questionnaires ask for.
The Correct Methodology — Free to Use
You do not need to pay anyone to tell you which methodology to follow. It is always the same:
GHG Protocol Corporate Standard (World Resources Institute / WBCSD) — the universally accepted framework. Free to download at ghgprotocol.org.
DEFRA 2023 Conversion Factors — the UK Government's annual emission factor publication. Free to download. Accepted globally as a credible secondary source when national factors are unavailable.
The Methodology Statement You Need
Paste this into any questionnaire's methodology field:
> "GHG Protocol Corporate Standard (WRI/WBCSD). Emission factors: DEFRA 2023 (UK Government). Scope 1: natural gas, diesel, petrol, LPG, and refrigerant leakage. Scope 2: purchased electricity, location-based, national grid factor. Scope 3: Category 3 (WTT upstream fuel), Category 5 (waste), Category 6 (business travel), Category 7 (employee commuting). Self-assessed. Reporting year: [YYYY]. Verification: [Carbon Passport URL]."
That statement passes methodology review on SAP Ariba, Coupa, Jaggaer, EcoVadis manual review, and standard email-based questionnaires.
When You Might Actually Need a Consultant
- ISO 14064 third-party verification — required by some regulated-sector buyers; needs an accredited external verifier
- CDP Gold-level disclosure — requires governance documentation beyond a standard GHG inventory
- Lifecycle assessment (LCA) — if your buyer requires product-level carbon footprinting, not just company-level
- SBTi target validation — the submission process itself is free, but a consultant can help with target calculation for complex multi-site organisations
For the standard procurement questionnaire scenario, none of these apply.
The Free Tool That Replaces the Calculation Work
DeCarbonOPS is a free carbon reporting tool built for EU SME suppliers. It applies DEFRA 2023 factors automatically, covers all material Scope 3 categories, and generates a Carbon Passport with a verification URL in under 20 minutes. No consultant required, no spreadsheet required, no GHG Protocol documentation required.
Create a free account, enter your utility data, and get your verified emissions report.
Frequently Asked Questions
What does a sustainability consultant actually do during carbon reporting?
A sustainability consultant collects your utility data, applies published emission factors, calculates Scope 1, 2, and 3 totals, writes a methodology statement, and formats the results. For a standard SME GHG inventory, this is exactly what DeCarbonOPS does automatically in 20 minutes. Consultants add genuine value for complex multi-site inventories, regulated disclosures, and lifecycle assessment work.
What methodology do I say I followed if I didn't hire a consultant?
GHG Protocol Corporate Standard — the same methodology every consultant uses. Write: 'GHG Protocol Corporate Standard (WRI/WBCSD). Emission factors: DEFRA 2023 (UK Government). Self-assessed using DeCarbonOPS. Reporting year: [YYYY].' Self-assessed GHG inventories are explicitly supported by the GHG Protocol and accepted by all major procurement questionnaires.
Can I do carbon reporting in a spreadsheet instead of a tool?
Yes. The calculations are arithmetic: multiply consumption by DEFRA factor, divide by 1,000. A spreadsheet works but requires you to find and apply the correct factors for each source and country, handle WTT calculations manually, and format the output yourself. DeCarbonOPS removes all of this and generates a shareable verification URL that a spreadsheet cannot produce.
What would a consultant charge for what DeCarbonOPS does for free?
A standard SME GHG inventory from a UK or EU sustainability consultancy typically costs €2,000–€5,000 for a first-year report, with annual update fees of €800–€2,000. DeCarbonOPS is free for one Carbon Passport per account. The output quality is comparable for procurement questionnaire purposes — the difference is speed, cost, and the self-service model.
When should I eventually hire a consultant for carbon reporting?
When your reporting requirements outgrow self-assessment. This typically happens when a buyer requires ISO 14064 third-party verification, when you pursue SBTi validation for a complex multi-site organisation, when you are required to disclose to CDP at Management or Leadership level, or when you need a product-level lifecycle assessment. For standard annual procurement questionnaire responses, self-assessed reporting with DeCarbonOPS is appropriate indefinitely.
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