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Welcome đ
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Ready to become an emission factor expert? Letâs build on what you learned in lesson two and go a layer deeper into this topic. In lesson three, youâll uncover:Â
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The two types of emission factors
To recap on lesson two, an emission factor is a number that helps estimate how much pollution comes from a specific activity, material, or fuel.
There are two types of emission factors:
- Primary emission factors
- Secondary emission factors
Letâs break them down in more detail:
Primary emission factors: Straight from the source
Primary data is information that comes straight from the source. Itâs a bit like getting a recipe directly from the chef instead of guessing what might be in the dish.
Primary emission factors are directly relevant to your organization, based on your owned activity data or shared by a supplier for a process in their control.
Here are some examples:
- Carbon footprint results from your suppliers (like cradle-to-gate PCFs) for the materials or services they supply to you
- Emission factors based on a fuelâs chemical makeup and burning process
- Emission factors shared by your electricity supplier for purchased energyÂ
Secondary data: A reliable backup plan
Secondary data is information collected, measured, or calculated elsewhere by other people. Itâs like using a cookbook instead of the chefâs personal recipe. It might not be completely accurate, but itâs good enough when youâve no access to anything else.
Secondary emission factors tend to be general averages, not specific to a product.
Some examples include:
- Industry benchmarks for your region
- Government reports and databases
- Environmentally extended input-output databases (such as Exiobase)
- Lifecycle assessment emission factor databases (such as Ecoinvent)Â
Where to find emission factors
| Source | Type | Description | Access | Where to Find |
| Supplier-Provided PCFs (Product Carbon Footprints) | Primary | Specific carbon footprint data provided by your suppliers for a product or process. | Direct request | Ask your suppliers for cradle-to-gate PCFs or emissions reports. Hereâs a template you can use. |
| Utility Emission Factors (e.g., electricity providers) | Primary | Emission factors related to your purchased energy, often provided in sustainability or tariff documents. | Public or on request | Check your electricity provider's website or request their fuel mix/emissions info. |
| DEFRA/BEIS Emission Factors (UK) | Secondary | UK Government-published average emission factors for activities like fuel use, transport, and energy. | Free | https://www.gov.uk/government/collections/government-conversion-factors-for-company-reporting |
| EPA Emission Factors Hub (US) | Secondary | EPAâs official emission factors for various sectors in the US. | Free | https://www.epa.gov/climateleadership/center-corporate-climate-leadership-ghg-emission-factors-hub |
| Ecoinvent | Secondary | Comprehensive LCA database with average emissions data across thousands of products and processes. | Paid | https://ecoinvent.org/ |
| Exiobase | Secondary | Input-output database for footprinting at the country and sector level. | Free | https://www.exiobase.eu/ |
| Climatiq | Secondary | Scientifically vetted emission factors across 20,000+ activities and 300+ regions. | Paid | https://www.climatiq.io/ |
| Bilans Carbone (ADEME) | Secondary | Emission factors for a wide range of processes and activities to calculate emissions of GHGs, with a focus on France. | Free | https://bilans-ges.ademe.fr/ |
| GaBi Database | Secondary | LCA software/database covering various industrial processes. | Paid | https://gabi.sphera.com/ |
| OpenLCA Nexus | Secondary | Platform with access to multiple LCA databases (some free). | Free & paid | https://nexus.openlca.org/ |
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Primary data share
Hereâs something interesting: every product carbon footprint comes with a primary data share (PDS). The higher the share, the more accurate and representative your product carbon footprint is likely to be.
Why does this matter? Well, if youâre trying to improve a product carbon footprint, this number helps you focus your efforts. Low number? Thatâs your cue to collect more primary data for your biggest emission sources.
Many businesses will start off with a low percentage of primary data. But itâs not something to worry about. The first step to aim for is completeness, no matter how much secondary data is used. Improving the share of primary data can come later.
Finding the right emission factor
So, youâve found a secondary emission factor database â how do you know if the emission factor in there is the right one for you?
When choosing a secondary emission factor to use, there a few things that affect which emission factor is the right choice:
- The chosen activity
- Any assumptions about the underlying technologies and processes used
- The location the emission factor is relevant to
- The scope of the factor
Most of the time, this information is kept in supporting documentation that accompanies a secondary emission factor source.
You may not be able to find an exact match for your own processes. Thatâs perfectly normal â just make sure you understand and keep a track of any assumptions you are making.
Check your knowledge
Time to see if it all makes sense! Take the quiz to check your understanding:
If your customers have asked you to complete M2030's Product Carbon Footprint Academy, taking this quiz will show them you're making progress. Your answers and scores will not be shared with them â only that you have taken the quiz.