# How do I add carbon criteria to supplier selection and purchase decisions?

Canonical: https://senseible.earth/answers/how-to-add-carbon-criteria-to-supplier-selection

Start with the few categories where most of your purchased emissions sit. Ask suppliers in those categories for document-backed emissions data in every quote, give carbon a fixed weight in your scoring or an internal carbon price in total cost, and write data sharing and reduction expectations into contracts.

## Step 1: find the hotspots

Rank purchased goods by spend and by a rough emissions estimate. Steel, aluminium, cement, chemicals, plastics and freight usually dominate for manufacturers. Apply carbon criteria to those first; for low impact spend, leave procurement unchanged.

## Step 2: ask for the data in the quote

The GHG Protocol Scope 3 guidance prefers supplier-specific data over averages, so data you collect here also improves your own Scope 3 inventory.

- Supplier Scope 1 and 2 emissions for the last year, with the invoices or bills behind them.
- For key materials, a product carbon footprint per tonne or per unit, with its boundary.
- Production route or recycled content where it drives emissions.
- Any reduction target or plan.

## Step 3: put carbon into the decision

ISO 20400:2017 gives guidance on building sustainability into procurement policy, criteria and contract management.

- Weighted scoring: give carbon a fixed share of the technical score and publish it in the tender.
- Total cost of ownership: add tonnes x an internal carbon price to each quoted price.
- Minimum requirement: for some items, refuse quotes with no emissions data at all.

## Step 4: write it into the contract

1. Annual sharing of emissions data in an agreed format.
2. Notice if the production route or energy source changes.
3. A reduction expectation, reviewed yearly, rather than a penalty on day one.
4. Right to see the evidence behind the figures.

## Worked example: two steel quotes with an internal carbon price

- Order: 1,000 t of steel; illustrative internal carbon price Rs 1,500 per t CO2e
- Supplier A: Rs 55,000 per t, 2.4 t CO2e per t. Price Rs 5.50 crore + carbon 2,400 x 1,500 = Rs 36 lakh. Total Rs 5.86 crore
- Supplier B: Rs 56,000 per t, 1.6 t CO2e per t. Price Rs 5.60 crore + carbon 1,600 x 1,500 = Rs 24 lakh. Total Rs 5.84 crore
- Supplier B wins by Rs 2 lakh once carbon is priced in

The carbon price is an internal choice, not a market price. Test the decision at two or three prices.

## What Senseible does here

Suppliers can share a document-backed Senseible record of their fuel and electricity emissions, and the supplier emissions risk calculator screens exposure across a supplier list. Senseible does not score tenders or rank suppliers for you.

- [Supplier due diligence](https://senseible.earth/supplier-due-diligence)
- [Supplier emissions risk calculator](https://senseible.earth/calculators/supplier-emissions-risk)
- [Which suppliers to engage first on Scope 3](https://senseible.earth/answers/which-suppliers-to-engage-first-on-scope-3)
- [Benchmarking a steel supplier's intensity](https://senseible.earth/answers/steel-supplier-benchmark-carbon-intensity)

Sources: [ISO 20400:2017, Sustainable procurement: guidance](https://www.iso.org), [GHG Protocol Technical Guidance for Calculating Scope 3 Emissions (2013)](https://ghgprotocol.org/corporate-value-chain-scope-3-standard)

Last reviewed 2026-10-15.