Supplier carbon footprint data: checklist and email
A free Excel checklist and an email template for people who collect carbon footprint data from suppliers. Use them for your corporate footprint (Scope 3) or for a product carbon footprint.
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Why is supplier data the hardest part of Scope 3?
In a corporate carbon footprint, purchased goods and services (Scope 3 category 1) are often the largest item. If you calculate them with average factors from databases or with the spend-based method, you cannot influence the result. It falls only when you buy less. Without supplier data, it is also hard to manage and cut emissions in the supply chain. So customers, banks and standards ask for data from the suppliers themselves. The trouble starts with the first request:
The supplier does not know what you ask for
A general request for “the carbon footprint” brings back an environmental policy or an ISO 14001 certificate, not a number.
A number with no unit and no context
You get the emissions of the supplier's whole company in tonnes of CO₂e. But you need a factor per kilogram, piece or tonne-kilometre of the product you buy.
Data you cannot compare
Each supplier used a different method, a different year and different boundaries. So you cannot compare or check the results.
Answers spread across your inbox
Files and numbers sit in emails and attachments. After a few weeks, nobody knows which suppliers have sent data and whom to chase.
Demand for supply chain data comes from several sides:
- Customers: they ask suppliers in ESG questionnaires about product carbon footprints and actions to cut emissions.
- Reporting under ESRS E1: companies under the CSRD must report Scope 3 emissions in their material categories.
- CDP: the questionnaire asks about Scope 3 emissions and how the company works with suppliers to cut them.
- SBTi targets: reduction targets cover Scope 3, so without supplier data it is hard to show progress.
Which Scope 3 categories need supplier data?
Under the GHG Protocol, a corporate carbon footprint has three scopes. You express emissions in kilograms or tonnes of carbon dioxide equivalent (CO₂e). Scope 1 covers direct emissions, for example from fuel burnt in your own boilers and vehicles. Scope 2 covers indirect emissions from purchased electricity and heat. A company calculates Scopes 1 and 2 from its own invoices and meters. Scope 3 covers all other indirect greenhouse gas emissions in the value chain, in 15 categories. Supplier data matters most where the emissions happen at the supplier:
- Category 1, purchased goods and services: raw materials, materials, components and services; often the largest part of the footprint in production and trading companies.
- Category 2, capital goods: machines, equipment and buildings bought in the reporting year.
- Category 4, upstream transportation and distribution: carriers and logistics operators can give transport emissions in kg CO₂e per tonne-kilometre (more about category 4). From 2 December 2030, they must calculate this result under the new EU rules.
- Category 5, waste generated in operations: the company that collects your waste knows how it is treated, and the emissions depend on it.
Other categories, for example business travel, usually come from data of the travel agency as a service supplier, or from financial data. Data from a specific supplier is called primary data. It replaces secondary data, that is average factors from databases or financial data converted with the spend-based method. The GHG Protocol recommends collecting primary data first where emissions are largest. It also matters where the company can influence the choice of supplier and how it buys.
What data should you collect from suppliers for a product carbon footprint?
From each supplier, you need more than the result. You also need information that shows if the result fits your report. In the checklist, we group it into four areas:
Supplier data
The supplier's name, the product or service you buy and the date of your request. Without them, a year later you will not know where a number in your report came from.
Data quality
Which standard the supplier used (GHG Protocol, ISO 14067, EPD), with the method and the sources of emission factors. Also the period, the place of production and the boundaries of the calculation.
Emission data
The result in kg CO₂e per unit of product (kg, piece, metre, tkm). Also a link to the invoice or delivery note, so you can multiply the factor by the real quantities.
Supplier engagement
Does the supplier have reduction targets? Are they validated, and is there a reduction plan? This is the basis for work on Scope 3 in the next years, not only for the report.
At the end, you answer one question: is the data from this supplier complete enough to use in the report? If not, use an average factor for this supplier and come back to it next year.
How do you check if supplier data fits your report?
The GHG Protocol guidance for Scope 3 recommends five data quality criteria: technological, time-related and geographical representativeness, completeness and reliability. In practice, this means five questions:
- Do you know how they calculated it?: a result without a named standard and a method description is a statement, not data for a report.
- Does the data cover your period?: a factor from several years ago may not match today's production or the supplier's energy mix.
- Does it cover this product and this plant?: an average for a whole corporate group, or for another country of production, distorts the result.
- Are the boundaries clear?: “cradle to gate” covers raw materials and production, but not transport to you. You must count transport separately.
- Did anyone check it?: verification by an external body, for example in an EPD based on a life cycle assessment (LCA), is not mandatory. But it makes the data more reliable.
You can use data that passes these questions instead of database factors. Treat other data as a starting point for a talk with the supplier.
How to ask suppliers for data?
- Choose suppliers: start with those behind the largest share of purchases or emissions. A Scope 3 screening helps you find them.
- Send a specific request: say why you need the data, which product it covers and in which unit, and give a deadline. Add that an EPD or a product carbon footprint report is enough if the supplier already has one.
- Keep answers in one place: one supplier, one column, the same questions. You see at once what is missing and whom to contact again.
- Check completeness: when you calculate the corporate footprint, use complete data in the calculation. Fill gaps with database factors or the spend-based method.
- Come back every year: suppliers with targets and a reduction plan will give you better data over time. They also bring a real fall in Scope 3 emissions.
The email template and the checklist guide you through steps two to four. So you do not start collecting Scope 3 data from a blank page.
What is inside?
Excel checklist
15 questions in four groups, with columns for 18 suppliers. You choose answers from a list (Yes, No, n/a). At the end, you decide if the data is complete enough for the report.
Email template for suppliers
Text to copy, with fields to fill in. It works for a corporate footprint (Scope 3) and for a product carbon footprint under ISO 14067.
How to use it
How to fill in the email template and how to move suppliers' answers into the checklist.
Who is this material for?
For people who calculate a corporate or product carbon footprint
It helps sustainability (ESG), purchasing and quality teams that collect supplier data for Scope 3 or a product footprint for the first time. It also helps companies that got a request for supply chain data from their own customer.
Why download this material?
Ready to use: you can send your first request today, without writing questions from scratch.
The same questions for all suppliers: you can compare the answers, assess them and use them in your calculation.
Based on the GHG Protocol and ISO 14067: the questions cover what you need for the report and its verification.
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See also
Scope 3 category 1: purchased goods and services
How to calculate emissions from purchases, and where to get the data.
Corporate carbon footprint under the GHG Protocol
We calculate Scope 1, 2 and 3 emissions, together with supplier data.
Scope 3 screening
How to find the Scope 3 categories that matter most.