A company carbon footprint

What a company carbon footprint is

The reference for measuring it is the GHG Protocol Corporate Accounting and Reporting Standard. It covers seven gases: the six of the Kyoto Protocol, which are carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF₆), plus nitrogen trifluoride (NF₃), which the GHG Protocol added in 2013¹².

Each gas warms the atmosphere with a different strength. To add them up, each one is converted to CO₂ equivalent based on its global warming potential: CO₂e is the common unit for comparing what is emitted, or avoided, across different gases¹.

This page covers the footprint of an organization, that is, its yearly greenhouse gas inventory, not the footprint of a product.

Scopes 1, 2 and 3, with examples

Scopes 1 and 2 are defined so that two companies do not count the same emission in the same scope¹. Scope 3 gathers everything else that happens in your value chain.

The Corporate Standard requires scopes 1 and 2 to be accounted for and reported separately at a minimum; there, scope 3 is an optional category¹. The 2011 Scope 3 Standard goes further: companies following it must account for all their scope 3 emissions and disclose and justify any exclusion³. The 15 categories and how waste is treated are in scope 3, waste and recycling.

How to calculate your company carbon footprint

The GHG Protocol organizes the calculation in five steps: identify the sources, select a calculation approach, collect activity data and choose emission factors, apply calculation tools and roll the data up to the corporate level¹. For a company in Mexico it looks like this:

1. 01

   Decide what you count

   Choose whether you consolidate by control (operational or financial) or by equity share. That tells you which plants, warehouses and vehicles are in your inventory¹.

2. 02

   List your sources

   Per plant: boilers, furnaces, vehicles, processes and electricity purchases. If you will measure scope 3, also purchases, freight, travel and waste.

3. 03

   Collect activity data

   Fuel invoices in liters or cubic meters, electricity bills in kWh, fleet logs and tonnes of waste by type and destination. Keep the document behind each number: it is your evidence.

4. 04

   Choose emission factors with a source

   For grid electricity, SEMARNAT asked companies to use the 2024 National Electricity System factor during the 2026 reporting period of the Cédula de Operación Anual: 0.444 t CO₂e per MWh, because the 2025 factor was still being estimated⁴.

5. 05

   Calculate

   Emissions = activity data × emission factor, gas by gas, converted to CO₂e. For example, 1,200 MWh of electricity × 0.444 t CO₂e per MWh = 532.8 t CO₂e of scope 2.

6. 06

   Set a base year

   Choose and report a base year for comparison, and define when you recalculate it, for example if you buy or sell a plant¹.

7. 07

   Report with an audit trail

   Report each scope separately and disclose assumptions, methods and data sources, so a third party can review it¹.

• 0.444 tCO₂e per MWh: the national grid factor for the 2026 Cédula de Operación Anual ⁴
• 25,000 tCO₂e per year or more: from there, direct and indirect emissions are reported to the RENE ⁵
• 15scope 3 categories in the GHG Protocol ³
• 7gases in the Corporate Standard: the six of Kyoto plus NF₃ ²

The five principles of a sound inventory

The GHG Protocol requires accounting and reporting to be based on five principles¹. ISO 14064 uses the same ones for quantification; we explain it in ISO 14064.

• Relevance

  The inventory reflects the company emissions and serves decision making, inside and outside the company.

• Completeness

  It includes every source within the chosen boundary. Anything excluded is disclosed and justified.

• Consistency

  The same methods from year to year, so results can be compared. Every change in data, boundary or method is documented.

• Transparency

  Every number has an audit trail: assumptions, methods and data sources in plain view.

• Accuracy

  Neither above nor below actual emissions, as far as can be judged, with uncertainty as low as practicable.

Common mistakes when calculating a footprint

• Subtracting recycling from the inventory. Emissions avoided by recycling are not included in or deducted from scope 3: they are reported separately⁶. See avoided emissions.
• Excluding categories without saying so. Minor activities can be left out, as long as the exclusion is disclosed and justified³.
• Using the electricity factor from another year. SEMARNAT publishes a notice with the grid factor for each reporting year⁵. Use the one for the period you report.
• Mixing estimates with real data without saying so. An average consumption works to get started, but it is documented as an assumption and replaced with the real figure once you have it.
• Adding up the scope 3 of several companies. The same emission can be scope 3 for several companies at once, which is why scope 3 is not added across companies to get a regional total³.
• Putting biomass CO₂ in scope 1. Direct CO₂ from burning biomass is reported separately, not inside scope 1¹.

Where recycling fits in your footprint

What you send for recycling, such as the scrap from your plant, is waste from your operations: it goes in scope 3 category 5, waste generated in operations⁶.

The GHG Protocol recommends the recycled content method: the emissions of the recycling process belong to whoever uses the recycled material, who reports them in their category 1. You only count the emissions of recovering the material, if they are not already in the factor of the recycled material⁶.

What is saved when that steel replaces steel made from ore is not subtracted from your footprint. If you report it, it goes separately, as avoided emissions, with data showing the material was collected, recycled and used⁶. We go into detail in scope 3, waste and recycling and avoided emissions.

How to use the Bluegreen certificate if you sell scrap

When you sell scrap through Bluegreen, each lot gets a certificate with a folio that anyone can verify online, without an account. Its CO₂e figure is net: what recycling avoids, counted only on the weight that reached the mill (the lower of the origin and destination net weights, so material lost on the way does not count), minus what each haul emitted.

• Transport is calculated as kilometers from the Carta Porte × tonnes carried × 100 g CO₂e per tonne-kilometer, the GLEC Framework v3.0 value for road freight in North America, well to wheel⁷. That is how ISO 14083 quantifies transport.
• Yard operations (cutting, baling, cranes) are not measured per lot yet and are not subtracted. The certificate says so.
• The current factor set is preliminary, and certificates with preliminary factors are not presented as verified.
• Bluegreen follows the GHG Protocol and the quantification principles of ISO 14064, and holds no ISO certification.

In your footprint, the certificate works as evidence of the tonnes you sent for recycling (the activity data for your category 5) and, separately, as support for avoided emissions. Do not subtract it from your scopes. See the full methodology and what each report includes.