OneCarbon · Methodology
Most GHG inventories are assembled backwards — from templates, not from emission sources. OneCarbon is One17's structured methodology for building inventories the right way — evidence comes first, with the numbers and disclosure following from it.
The Problem
Organisations reach for GRI or ISSB templates before they've mapped where their emissions actually come from. The result looks complete, but the numbers aren't traceable.
Data that passed internal review fails when a third-party verifier asks for the source document behind a figure. By then, it's costly to fix.
Over-engineered platforms and dashboards that require specialist knowledge to operate — and break down the moment the person who built them leaves.
Category-level figures in the report that no one can trace back to activity data or a documented emission factor. These don't survive even a desk review.
The OneCarbon Process
Each stage of the OneCarbon process produces a specific evidence artefact — a record that holds up under third-party verification. The process is lean by design: it works with the data and team you already have, sized to your actual reporting requirements.
What Makes OneCarbon Different
We map every emission source to a primary document before any calculation starts. There are no figures in the final inventory that can't be traced back to a source record.
The process is structured the way a third-party verifier thinks. We've been on the other side of the audit — so we build evidence systems that hold up when the questions come.
The methodology comes without a platform, a dashboard, or a licence fee attached. It's delivered as a consulting engagement, and your inventory belongs to you, in formats you can use.
We work with your existing data and team. The OneCarbon process is sized to the organisation — no over-engineering, no complexity for its own sake.
A template tells you what to fill in. A methodology tells you why the number exists and how to defend it if someone asks. OneCarbon delivers the latter.
Every inventory we produce includes the documentation and procedures your team needs to update it next year — without needing to start from scratch or re-engage an adviser.
“Most of the client data I verify still lives in spreadsheets, entered by hand. That's usually where the errors creep in — and where the final inventory number quietly goes wrong.” — CH Tan, ISO 14064 Verifier
What You Receive
Formal record of organisational and operational boundary decisions, including rationale for inclusion and exclusion of emission sources.
Complete register of all emission sources within scope, each one linked to a data owner and a quality rating, with the source document on file.
Fully documented calculation workbook with activity data, emission factors, GWP values, and tCO₂e outputs — all traceable to source records.
Complete inventory report aligned to GHG Protocol and ISO 14064-1, ready to hand to a customer questionnaire or a regulator without rework.
Tell us about your reporting requirements and we'll explain how the OneCarbon process applies to your organisation. No obligation, no over-engineering.
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