Guide
Supplier Emissions Data: We Estimate First, Then Ask a Few Suppliers for the Records That Matter
A questionnaire sent to every supplier produces a large file and little insight. We begin with a rough estimate from your own records, then ask a few suppliers for the plant data that matters most.
4-minute read5 November 2026
In Brief
- A survey of the whole supplier base returns partial answers in mixed units from those who found it easiest to reply, and these may not be the suppliers who drive the emissions.
- We see four actions: estimate everything from your purchasing records, keep a value list and an emissions list, ask a dozen suppliers for fuel, electricity and output, and grade what returns.
- Thinqmesh sets up one system of record where each figure links to its source and method, then brings supplier data in as it arrives, within an eight-week plan.
The common first move on supplier emissions is a questionnaire to the entire supplier base. It feels thorough and is easy to delegate. The likely return is a partial response in mixed units, from the suppliers who found it easiest to answer, and these may not be the ones responsible for the emissions. Our approach is to begin with your own purchasing records, accept that the first estimate is rough, and then approach a small number of suppliers with precise requests.
Two Rankings Answer Two Different Questions
SEBI's framework for value chain disclosures defines the value chain by the share of purchases and sales that partners account for by value. That is a financial test, and spend does not always follow emissions. A modest spend on forging or foundry work done on furnace oil can matter more to your footprint than a large spend on assembled parts.
Both lists are worth keeping. The first tells you whom a disclosure would cover, and the second tells you where better data would change what you know. Without the second, requests go to the wrong suppliers and the effort of reading the answers is spent on figures that move the total very little.
Four Actions That Give Supplier Data a Sensible Order
Each narrows the request, so you ask a few suppliers for the right records and treat the rest with an estimate you can defend.
Estimate Everything From Your Own Purchasing Records
A rough first pass ranks the activities, and the ranking tolerates more error than the total does.
We group your purchases by material and process, in physical quantities where the ledger allows and by value otherwise, and apply published factors. The result is imprecise, which is acceptable at this stage, because its job is to show relative size and the places where better data would change what you know.
Get started
- Export a year of purchases with quantities and suppliers.
- Group them by material and process, and sort by size.
Keep Two Lists That Answer Different Questions
A list by value shows whom a disclosure would cover. A list by emissions shows where better data pays off.
The disclosure framework SEBI sets for the value chain is built on purchases and sales by value. Spend may not track emissions, and a smaller spend on heat treatment, forging or foundry work can carry more of the footprint than a large spend on assembled parts. We maintain both lists and keep clear which question each answers.
Get started
- Rank your suppliers by spend.
- Rank them again by estimated emissions and compare the two.
Ask a Few Suppliers for Records They Already Hold
Electricity units, fuel used and tonnes of output from the supplier's own books.
When the ranking has named a dozen or so suppliers, the request is narrow. A number you can recalculate from fuel, electricity and output is more useful than a finished carbon figure of unknown method. We write the request, the units and the period, so the replies can be compared.
Get started
- Pick your top ten suppliers by estimated emissions.
- Draft one request that names the three records and the period.
Grade What Returns, and Write the Method Down
Each figure carries a grade for its quality and a note of how it was obtained.
Data returns at different quality, and the grade tells your auditors which figures rest on supplier records and which on estimates. We record the source, the method and the grade against each figure, so a reader can follow it back and next year's update starts from the same footing.
Get started
- Choose a simple scale for data quality, such as measured, calculated or estimated.
- Record the source and method beside every figure you already report.
How Thinqmesh Solves This
We begin with the data, and every figure links to its source and its method. The system of record is set up on your energy, travel and supplier data within four weeks, with a first traceable footprint planned at eight.
- Week 1
Your Energy and Travel Data
We gather your energy and travel data and establish where each figure comes from.
- Week 2
Supplier Data and Methods
Supplier data is requested and assessed, and each calculation method is written down.
- Week 3
Connection to Your Systems
The system of record is connected to the sources you already use, so figures can be followed back to them.
- Week 4
A System of Record in Use
Your team is working from one system of record, with gaps in the data visible ahead of the first footprint.
You finish with one system of record, a carbon inventory with sources and methods written down, and a report your auditors and customers can follow back to source.
