You have collected your electricity bills, your fuel logs, and your travel records. You know that your office used 12,000 units of electricity last year. But how do you turn that figure into a greenhouse gas number? The answer is an emissions factor — and understanding how these multipliers work is fundamental to accurate carbon accounting.
What Is an Emissions Factor?
An emissions factor is a number that represents the average greenhouse gas emissions produced per unit of a specific activity. It acts as a conversion rate: you multiply your activity data by the relevant emissions factor to get a CO₂ equivalent (CO₂e) figure.
The basic formula is:
Emissions = Activity Data × Emissions Factor
For example, if your office consumed 12,000 kWh of electricity from the Indian grid, and the relevant emissions factor for that grid is 0.82 kg CO₂e per kWh (a commonly referenced figure for India’s average national grid), your calculated Scope 2 emissions from electricity would be approximately 9,840 kg CO₂e — or roughly 9.8 tonnes CO₂e.
Where Do Emissions Factors Come From?
Emissions factors are derived from scientific and engineering research. They are published by recognised bodies and updated periodically as energy mixes and technologies change. Key sources include:
- Ministry of Power / Central Electricity Authority (CEA), India — Publishes annual CO₂ baseline database for the Indian electricity grid, broken down by regional grids.
- IPCC Guidelines for National Greenhouse Gas Inventories — The global reference point for default emissions factors across fuel types, industrial processes, and agriculture.
- GHG Protocol — Provides supplementary factors and tools for Scope 1, 2, and 3 calculations.
- UK Government DEFRA Conversion Factors — Widely used internationally for Scope 3 emissions where local factors are not available.
Types of Emissions Factors
Not all emissions factors are the same. The type you use depends on the activity, the data available, and the reporting framework you are following.
Location-Based vs Market-Based (Scope 2)
For Scope 2 electricity emissions, the GHG Protocol distinguishes between two approaches. The location-based method uses the average emissions intensity of the regional grid. The market-based method uses supplier-specific factors — relevant if your business has a power purchase agreement for renewable energy or holds renewable energy certificates (RECs).
Default vs Supplier-Specific Factors
For Scope 3 categories — like purchased goods or business travel — you often have to use default or average factors when supplier-specific data is unavailable. These are less precise but acceptable as a starting point. As your net zero journey matures, you can replace default factors with more accurate, activity-specific data.
Why Emissions Factor Selection Matters
Using the wrong emissions factor can significantly distort your emissions figures — either overstating or understating your actual impact. Common mistakes include:
- Using an outdated factor (India’s grid intensity changes year on year as more renewables come online)
- Using a global or US factor where an India-specific factor exists
- Applying a national average factor when a more granular regional or state-level factor is available
- Conflating location-based and market-based factors in the same inventory
For credible ESG reporting and audit readiness, you should document which emissions factor you used for each activity, its source, and the year it was published.
Practical Application: Key Factors for Indian Businesses
Here are the most commonly used emissions factors for typical Indian business activities:
- Electricity (Indian national grid) — Published by CEA; typically in the range of 0.7–0.82 kg CO₂e/kWh depending on the reference year and regional grid.
- Diesel — Approximately 2.68 kg CO₂e per litre (IPCC reference).
- Petrol / Gasoline — Approximately 2.31 kg CO₂e per litre.
- Compressed Natural Gas (CNG) — Approximately 2.21 kg CO₂e per kg.
- Domestic air travel — Economy class short-haul, approximately 0.255 kg CO₂e per passenger-km (DEFRA).
These figures are illustrative. Always verify against the most recent published version of your chosen source before using them in a formal report.
Keeping Your Emissions Factors Up to Date
As India transitions to sustainable energy at scale — with solar and wind making up an increasing share of the grid — the national electricity emissions factor is expected to decline over time. This means businesses that report their emissions using grid electricity will naturally see a reduction in Scope 2 figures even without changing their actual consumption, simply because the grid is getting cleaner.
This is a genuine emissions reduction (the grid is decarbonising), but it should be reported accurately and not conflated with operational efficiency improvements your business has made directly.
Understanding emissions factors is one building block in a complete carbon accounting system. Next in this series, we look at how to build a basic emissions inventory — bringing activity data and emissions factors together into a structured first report.