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How to choose the right emission factor database: A guide for accurate carbon inventories

Misha Cajic
Misha Cajic
Co-Founder & Co-CEO, Avarni
August 5, 2024
/
10
min read

When creating an emissions inventory for your clients to report to customers and regulators, it’s important to choose reputable, high quality factor database to ensure the inventory passes the scrutiny of a future audit, and reports the most accurate emissions for your client to take action on.

There are a few things that influence which database will be the most appropriate to use for your client’s data:

  • Data available to analyze – This is by far the most important to evaluate prior to choosing the right database, since the same business activities can often have different representations. Eg: Distance data or fuel data for travel, spend data or amounts purchased for supply chain goods and services, etc.
  • Nature of the client’s business – Are their operations centralised in one geography, or spread out across a large area of the globe? Are they an energy producer or a retailer of with most of their activities in the supply chain?
  • Reporting needs – Are they required to use primary data for certain categories, such as in CSRD, or is secondary data sufficient?
  • Client goals – Do they want the most accurate footprint, or the lowest footprint, or both? There is more than one valid way to create an inventory due to the range of databases out there, so knowing what your client wants is key.

Examples

Retail client in the US with most of their activity in the supply chain and distribution domestically

The main categories of emissions will be purchased goods and services, upstream transportation and distribution, and energy use for facilities and retail sites that are owned/operated by them.

To get a baseline for PG&S, it would be most appropriate to use the EPA EEIO factors, since they are US specific, and also very granular (with 1,018 categories available to match to).

A sample of EPA EEIO factors
A sample of EPA EEIO factors for supply chain emissions calculations using spend

There are also comprehensive energy grid factors available in the EPA database, which would be appropriate to apply to energy use at its various facilities.

The EPA also has factors available for use for transport in the form of mobile combustion factors (such as Motor Gasoline & Diesel Fuel) and distance factors (such as Passenger Cars, Light-Duty Trucks) – but if an appropriate factor is not available, BEIS has distance based factors for different types of trucks & air freight that can be used too.

Energy client that produces their own electricity in Argentina

The primary source of emissions for this type of client would be Scope 1, for the fuel sources they burn to generate electricity. In Argentina, the primary sources of electricity are natural gas and oil.

However, Argentina does not have a comprehensive emission factor database available from its government. But since the emissions from the same type of fuel burnt anywhere in the world are likely to be similar, we can safely use a different database, such as the EPA, to measure these emissions, even though they are not specific to Argentina.

Small/medium sized manufacturer looking to report the lowest footprint that supplies glass to a retailer

This manufacturer is required to comply with a request on a competitive RFP issued by a retailer to provide emissions data, and wants to report the lowest footprint with a valid methodology.

Different factor databases are likely to end up with a different emissions number for the same inventory, even if the methodology for both is valid. For example, the EPA has a factor for Glass product manufacturing made of purchased glass in 2019 with a value of 0.49 kg CO2e per USD.

EPA factor for glass products

However, if you used EXIOBASE, the most appropriate factor to use would be Glass and glass products, which has a value in 2019 for the US of 0.60 kg CO2e per USD.

EXIOBASE factor for glass products

Both options would be valid and pass an audit, but the emissions for this product would be 22% higher when using EXIOBASE instead of EPA – so using EPA would align more closely with the goals of the manufacturer.

An even more accurate inventory, that may end up having the lowest footprint, could be created using an activity based factor database (such as ecoinvent) instead of spend based.

Electronics manufacturer based in Europe with global supply chain seeking an initial baseline

With a global supply chain, using region & country specific emission factors will be critical in order to build a meaningful, credible emissions reduction plan, and understand where certain procured materials are more emissions intensive.

Even if the manufacturer is buying many different types of components from suppliers around the world, the need to understand the emissions intensities across different regions requires use of a database such as EXIOBASE, which has spend-based emissions factors for around 150-200 unique goods & services across 44 countries and 5 broader regions, to ensure coverage where country specific factors aren’t available.

Emission factor for Aluminium ores and concentrates across different countries
Emission factor for Aluminium ores and concentrates across different countries

This would enable the manufacturer to see that the emissions intensity of Aluminium sourced from Hungary is 320% higher than sourcing the same material from Croatia, allowing them to evaluate the costs of switching their supply of this material to Croatia to lower their emissions for this material & show the regulator they have a credible plan to decarbonise.

Finding the right database

There are many freely available databases, published either by government or industry bodies, that are widely used for emissions inventories today. Here are some of the most popular:

Emission Factor Source Description Unit types Year(s) Geographic coverage
EPA (Environmental Protection Agency): The United States Environmental Protection Agency provides guidance on greenhouse gas emission factors through various tools and reports, including the Greenhouse Gas Reporting Program (GHGRP) and publications like the Emission Factors Hub. Volume, mass, spend, energy 2018, 2019, 2020, 2021, 2022, 2023 United States, often used globally
DISER (Department of Industry, Science, Energy and Resources): This Australian government department provides national guidance on emission factors, primarily through the National Greenhouse Accounts Factors, which offer comprehensive data for calculating greenhouse gas emissions. Volume, mass, energy 2022, 2023 Australia
EXIOBASE This is a detailed and comprehensive global multi-regional input-output database that offers data on the environmental impacts of products and services, including emission factors across different industries and countries. Spend 2019 Global
BEIS
(formerly known as DEFRA)
(Department for Business, Energy & Industrial Strategy): The UK government department provides annual greenhouse gas conversion factors for company reporting, allowing businesses to calculate their carbon footprints. Volume, mass, spend, energy, distance, mass-distance, passenger-distance, time, room-night 2023, 2022, 2021, 2016 United Kingdom, often used globally
CT (Carbon Trust): An organization that helps businesses and organizations reduce their carbon emissions, the Carbon Trust provides emission factors as part of their carbon footprinting tools and services. Energy 2018, 2019, 2020, 2021 Argentina, Australia, Bangladesh, Brazil, Canada, China, Colombia, Germany, France, United Kingdom, Indonesia, India, Italy, Japan, South Korea, Mexico, Nigeria, Nepal, Philippines, Pakistan, Russia, Saudi Arabia, Turkey, United States, Vietnam, South Africa
DEWA (Dubai Electricity and Water Authority): While primarily a utility provider, DEWA may offer region-specific emission factors relating to electricity and water usage for use in carbon footprint calculations in the Middle East. Energy 2020 United Arab Emirates
Government of Canada The Canadian government provides emission factors and guidance for greenhouse gas inventory and corporate reporting through resources like the National Inventory Report. Energy, volume 2015, 2016, 2017, 2018, 2019, 2020, 2021 Canada
GHG Protocol (Greenhouse Gas Protocol): Offers a widely-used set of tools and standards for companies and governments to measure, manage, and report their greenhouse gas emissions, including emission factors. Distance, volume, energy, mass, mass-distance, passenger-distance 2021 Globally applicable, with some region specific factors
WRAP (Waste and Resources Action Programme): An organization that works with governments, businesses, and communities to deliver practical solutions to improve resource efficiency, WRAP provides emission factors related to waste reduction and recycling. Volume, mass 2015, 2018, 2019, 2020, 2022 United Kingdom
OEKOBAUDAT (ÖKOBILANZDATEN): This is a German environmental database for building materials and components. It provides data for life cycle assessment, including emission factors for the construction sector. Mass, volume, area, distance 2017, 2018, 2019, 2020, 2021, 2022 Turkey, Luxembourg, Italy, United Kingdom, Germany, Switzerland, Brazil, Bulgaria, Austria
UBA (Umweltbundesamt): The German Environment Agency provides emission factors for various environmental and sustainability assessments, contributing to national and international environmental data. Energy, mass-distance, passenger-distance 2016, 2017, 2018, 2019, 2020, 2021, 2022 Germany
GLEC (Global Logistics Emissions Council): Provides a framework and emission factors for calculating logistics emissions, including freight transport and related activities. Volume, mass, mass-distance 2019 United States
GEMIS (Global Emission Model for Integrated Systems): An open-source software model that evaluates energy systems and their associated environmental impacts, including greenhouse gas emissions across various sectors. Volume, energy, mass 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2021 Germany

There are also some licensed databases that are available for use, particularly for categories such as purchased goods and services with activity based data instead of spend based data:

  • ecoinvent
  • IEA (International Energy Agency)
  • CEDA

Other databases can be found by searching online or on government websites, but most calculations can be done using the databases above.

Applying the right factors from a database

Once you have chosen the emission factor databases you will use for your client’s inventory, you will need to apply the factors to their business activity data. For a detailed guide on how to do this, you can refer to our article: How to use emission factors to build a carbon inventory from business activities.

Summary

To choose the right database or combination of databases to apply to your client’s business activities to create an emissions inventory, you need to:

  1. Consider the data available (activity, distance data, spend), nature of the client’s business (type of product created, global supply chain, operations limited to a certain region), reporting needs (requirements of regulation client falls under), and goals (qualify for RFPs, align with brand purpose).
  2. Find the right databases based on the considerations above.
  3. Apply the emission factors to the business activities

Want to find the right databases without needing to manually perform all the above steps? Avarni includes all the open-source databases mentioned here in one place, and can help by:

  • Showing you all the emission factor databases, and associated factors, applicable to a certain region, country, or even address (eg. What factors can be applied to a distribution centre in Amsterdam, Netherlands?)
  • Filtering out databases automatically that are not applicable based on the type of data your client has available (eg. EXIOBASE cannot be applied to energy units).
  • Applying comparisons of different databases to the same business activity data to compare the final carbon footprint (eg. EXIOBASE vs EPA).
  • Automatically apply the right factors from a database using AI to get the most accurate, auditable inventory that will pass the scrutiny of regulators & large customers.

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