EEIO Model (Environmentally Extended Input-Output)
An economic modelling approach that estimates environmental impacts by mapping the interdependencies between sectors of the economy, used as the basis for spend-based emission factors in Scope 3 calculations.
What is EEIO Model (Environmentally Extended Input-Output)?
Environmentally Extended Input-Output (EEIO) models combine national economic input-output tables with environmental data to estimate the greenhouse gas emissions associated with the production of goods and services in each sector of the economy. They provide the emission factors (kgCO₂e per £ or $ of spend) that underpin the spend-based method for Scope 3 calculation.
The most commonly used EEIO databases include: DEFRA/DESNZ UK Environmental Accounts (for UK-based analysis), Exiobase (a multi-regional input-output model covering 49 countries), the US EPA USEEIO model, and the Carnegie Mellon EIO-LCA model.
EEIO factors represent sector-average emissions per unit of economic output. Their strength is coverage — they provide factors for virtually every type of procurement expenditure. Their limitation is granularity — they cannot distinguish between a low-carbon and high-carbon supplier within the same sector.
Best practice is to use EEIO-based spend factors as a starting point (screening all Scope 3 categories) and then progressively replace them with activity-based or supplier-specific data for material categories. This hybrid approach improves accuracy where it matters most while maintaining coverage across the full value chain.
Practical Examples
A consultancy firm uses DEFRA spend-based emission factors (derived from UK EEIO tables) to screen all 15 Scope 3 categories, identifying IT services and business travel as its top two emission sources.
A multinational uses Exiobase EEIO factors to estimate supply chain emissions across its global operations, accounting for the different carbon intensity of production in each country.
A public sector organisation applies EEIO factors to its full procurement budget as an initial Scope 3 screening, then commissions detailed LCA studies for the three most material categories.
How Climatise Helps
Climatise incorporates EEIO-based emission factors from DEFRA and international databases, enabling automatic spend-based Scope 3 calculations. As you gather better data from suppliers, the platform seamlessly transitions from spend-based to activity-based or supplier-specific calculations.
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