Open CEDA: A game changer for scope 3 emission factors

The importance of accurate scope 3 emission factors

Scope 3 emissions (as defined by the GHG Protocol) are the indirect greenhouse gas (GHG) emissions that primarily arise from your supply chain. They are often the hardest GHG emissions to measure. This difficulty stems not from a lack of knowledge about your supply chain, but from the challenge of finding accurate, relevant, and consistent emission factors.

Many consultants rely on the freely available US EPA emission factors. However we have for a long time opted for a different approach because we want our emission factors to be relevant to the countries in which our clients operate (the UK and others). Using US figures, even if adjusted for inflation and currency do not give an accurate assessment because other factors, such as electricity fuel sources and transport methods, vary greatly between countries.

Recently, the Trump Administration halted the publication of US EPA emission factors which means those consultancies and software providers using these factors will need to find new sources.

Introducing CEDA emission factors

CEDA by Watershed are country-specific emission factors that enable the easy conversion of supply chain spending into GHG emissions based on supplier industry.

Historically CEDA has provided only one set of emission factors (the 'enterprise' emission factors) however in response to the discontinuation of US EPA emission factors, Watershed has released a second, streamlined version of their dataset called Open CEDA.

What is Open CEDA?

Open CEDA was launched in May 2025 and will receive annual updates. It is available as an MS Excel database containing spend-based emission factors that are:

• Fit for Purpose: Conform with the spend-based method calculations permitted under the GHG protocol and the Science-Based Target initiative (SBTi).

• Open to Everyone: A publicly accessible database with no paywalls.

• Formed from a Robust Methodology: Founded on high-quality national information and employing the recognised environmentally extended input-output (EEIO) model, Open CEDA ensures credibility and accuracy.

• Globally Relevant: The database includes 60,000 emission factors across 149 countries, in various currencies, covering 400 industries.

  
  

What this means for your business

Open CEDA makes supply chain GHG emission calculations more accessible. It empowers companies that have not previously measured their supply chain emissions to do so independently, thus starting their decarbonisation journey.

For businesses that have previously relied on US EPA sources, Open CEDA is a valid alternative to switch to. When doing so companies should remember to retrospectively apply Open CEDA to their base year because emission changes cannot be realised as a result of a method change when they change emissions by >5% (as per SBTi). From our experience, this scenario is highly likely.

When to consider Enterprise CEDA

While Open CEDA provides a solid foundation for many companies' scope 3 supply chain calculations, some organisations have specialised reporting needs that exceed the capabilities of the open dataset. This is where the Enterprise CEDA version becomes essential.

Reasons to use Enterprise CEDA

Your company might need the Enterprise version if:

1. Your supply chain has FLAG emissions: Forest, Land, and Agriculture (FLAG) emissions arise from land management and land use changes. These emissions are particularly relevant for companies in agriculture, forestry, food and beverage, and apparel and textiles sectors. Companies should report FLAG emissions where significant and per the SBTi, if they are >20% of the company's footprint, set targets against these. Of course in order to assess this, they need to be measured. Open CEDA includes some land management emissions but does not allow disaggregation of these into non-FLAG and FLAG sources. Enterprise CEDA in contrast provides separate non-FLAG and FLAG emission factors (the latter by spend or weight) for 150 additional agricultural commodities.
   

2. You need to meet a scope 3 target: Transitioning to supplier-specific emissions is crucial for achieving supply chain emission reductions. Unfortunately, if suppliers do not have their full scope 1, 2, and 3 GHG footprints measured, their data cannot be used.

   
   

   Enterprise CEDA addresses this issue by disaggregating industry emission factors into those related to a supplier’s scope 1 and 2, and those related to a supplier’s scope 3 sources. This allows companies to adopt at least partial supplier-specific emissions as soon as their supply chain begins measuring scope 1 and 2 emissions, without waiting for all scope 3 emissions to be measured. This is particularly relevant for manufacturing suppliers, who typically have a higher proportion of scope 1 and 2 emissions than service-based suppliers.

   
   

In practice, we tend to utilise the Enterprise CEDA version for our clients. We know that this approach enables more accurate and granular emissions measurement which supports reduction planning and target achievement.

Getting started with Open CEDA

Is your business ready to leverage Open CEDA? Here’s how you can get started:

• Access the dataset: CEDA by Watershed: Carbon emissions data to drive climate action – Watershed

• Read supporting documentation: Check out CEDA’s FAQs and methodologies.

  
  

If you need assistance with restatements arising from the transition to Open CEDA, or if you want support implementing Enterprise CEDA and setting carbon reduction targets, contact us.

Authored by Amy Whitcher.