Emission Factor Database

An Emission Factor (EF) Database is a collection of standardized values used to estimate greenhouse gas (GHG) emissions from various activities (e.g., burning fuel, using electricity, transporting goods). Each emission factor represents the amount of CO₂e released per unit of activity — for example, kilograms of CO₂e per liter of diesel burned.

Emission factor databases are critical for carbon accounting, especially when direct measurement of emissions is not feasible. These databases are maintained by governments, international bodies, and private organizations, and often vary by region, sector, fuel type, or technology.

1. What is an emission factor?

An emission factor is a coefficient that quantifies the emissions released per unit of activity. For example:

• 2.68 kg CO₂e/liter of diesel combusted

• 0.233 kg CO₂e/kWh of electricity in the UK (2023 grid average)

2. What is an emission factor database?

It is a compiled set of these factors, organized by activity, fuel, process, or geography, allowing users to estimate emissions using a standardized approach.

3. Where do emission factors come from?

They are developed based on:

• Empirical testing and scientific studies

• National inventories and research institutions

• Industry reports or international bodies like:

o IPCC (Intergovernmental Panel on Climate Change)

o DEFRA (UK)

o EPA (US)

o IEA, GREET, ecoinvent, etc.

4. Why are emission factor databases important?

They provide a consistent, credible, and practical way to estimate emissions, especially when direct measurements are unavailable. They are essential for:

• Carbon accounting (Scopes 1, 2, and sometimes 3)

• Sustainability reporting (e.g., CDP, GHG Protocol, CSRD)

• Life Cycle Assessments (LCAs)

5. How are emission factors used in carbon calculations?

Basic formula:

Emissions (CO₂e) = Activity Data × Emission Factor

For example:

500 litres of diesel × 2.68 kg CO₂e/litre = 1,340 kg CO₂e

6. Are emission factors the same globally?

No. Emission factors vary based on:

• Geographic region (e.g., grid electricity mix in France vs. India)

• Fuel quality and type

• Technology used

• Temporal updates (e.g., annual grid decarbonization)

7. What are common emission factor databases?

• IPCC Guidelines – global standard

• DEFRA/BEIS (UK) – detailed factors for UK-based reporting

• EPA (US) – for US emissions estimation

• ecoinvent – LCA and product-level footprints

• GREET – transport and fuels

• EXIOBASE – environmentally extended input-output database for Scope 3

8. How often are databases updated?

Annually or biennially, depending on the publisher. It’s important to use the latest version for compliance and accuracy.

9. Can you use multiple databases?

Yes, but be cautious. Ensure consistency in methodology and geographic relevance. Mixing datasets can introduce errors if not well-documented.

10. Are emission factors accurate?

They’re estimates, not exact measurements. Accuracy depends on:

• Data quality

• Activity specificity

• Local relevance

Still, they’re the best-practice standard for estimating emissions where direct measurement is impractical.

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