Scope 2 Emissions Calculation from Electricity: Step-by-Step Guide

Calculating Scope 2 emissions from purchased electricity is one of the most common requirements in ESG questionnaires. Unlike Scope 1 (direct emissions from fuel you burn) or Scope 3 (supply chain emissions), Scope 2 focuses specifically on emissions from the electricity, steam, heating, or cooling you purchase. For most small and mid-sized suppliers, electricity is the dominant Scope 2 source.

The Basic Calculation Formula

The fundamental calculation is straightforward:

Electricity Consumption (kWh) × Emission Factor (kgCO2e/kWh) = Emissions (kgCO2e)

Convert kilograms to metric tons by dividing by 1,000. That's the number you'll report in questionnaires.

Worked Example

Your facility consumed 50,000 kWh of electricity in 2025. Your grid emission factor is 0.485 kgCO2e/kWh.

• 50,000 kWh × 0.485 kgCO2e/kWh = 24,250 kgCO2e
• 24,250 kgCO2e ÷ 1,000 = 24.25 tCO2e

Your Scope 2 emissions are 24.25 metric tons of CO2 equivalent.

Finding Your Electricity Consumption

Start with your electricity bills. Look for total kWh consumed, usually displayed prominently. If your bill shows consumption by time period (peak/off-peak) or by meter, sum these to get total monthly consumption. Add all 12 months for your annual total.

If you operate in multiple countries or regions with different grids, you'll need separate calculations for each location using the appropriate emission factor.

Location-Based vs Market-Based Methods

The GHG Protocol defines two approaches for Scope 2 calculation, and many questionnaires now ask for both.

Location-Based Method

This uses the average emission intensity of the grid where your electricity is consumed. It reflects the actual emissions from the regional power generation mix. This is the simpler method and represents physical reality.

Use emission factors from your national or regional grid. For the location-based method, you don't adjust for any renewable energy purchases or contracts.

Market-Based Method

This reflects emissions from the electricity you've specifically chosen through contracts, renewable energy certificates (RECs), or supplier-specific emission rates. If you haven't purchased green power or RECs, your market-based number typically equals your location-based number.

If you've purchased renewable energy or RECs covering 100% of consumption, your market-based Scope 2 can be zero, while location-based remains unchanged. This dual reporting shows both your contractual choices and your grid impact.

Where to Find Grid Emission Factors

Accurate emission factors are critical. Here's where to find them:

International Energy Agency (IEA)

The IEA publishes national emission factors for electricity generation by country. These are widely accepted for location-based calculations and updated regularly.

National Registries and Government Sources

Many countries publish official grid emission factors:

• UK: DEFRA emission factors (updated annually)
• USA: EPA eGRID (by subregion, more granular than national average)
• EU: European Environment Agency emission factors
• Australia: Australian government National Greenhouse Accounts Factors

Utility-Specific Factors

Some electricity suppliers publish their specific emission factors. If available, these can be used for market-based calculations when you have a direct supply contract.

Handling Multiple Locations

If you operate facilities in different grid regions, calculate each separately:

• Facility A (UK): 30,000 kWh × 0.212 kgCO2e/kWh = 6.36 tCO2e
• Facility B (Germany): 20,000 kWh × 0.348 kgCO2e/kWh = 6.96 tCO2e
• Total Scope 2: 13.32 tCO2e

Report the combined total, but maintain location-specific records in case questionnaires ask for geographic breakdowns.

Renewable Energy Certificates and Green Power

RECs (or Guarantees of Origin in Europe) are tradable certificates proving that one MWh of renewable electricity was generated. Purchasing RECs allows you to claim renewable electricity for your market-based Scope 2 calculation.

If you purchased 50,000 kWh worth of RECs (50 MWh) and consumed 50,000 kWh:

• Location-based Scope 2: 24.25 tCO2e (unchanged)
• Market-based Scope 2: 0 tCO2e (RECs apply zero emission factor)

Ensure your RECs match the reporting year and geographic market. Vintage and vintage matching rules matter for credible reporting.

Common Calculation Mistakes

Watch out for these errors:

• Unit mismatches: Mixing kWh and MWh, or using the wrong emission factor units
• Outdated factors: Using emission factors from years prior to your reporting period
• Wrong geography: Applying national factors when regional factors are available
• Double counting: Including electricity in both Scope 1 and Scope 2 (on-site solar generation is outside Scopes, purchased electricity is Scope 2)

Documentation for Questionnaires

ESG questionnaires may ask for supporting information. Keep records of:

• Electricity bills showing consumption
• Source of your emission factor (publication, year, region)
• Calculation methodology (location-based and/or market-based)
• REC certificates if applicable

Tools like ESG Passport allow you to store this documentation alongside your calculated figures, making it easy to provide evidence when customers request verification.

When Calculations Get Complex

Most small suppliers can handle Scope 2 with the basic approach outlined here. You may need expert help if you have: on-site renewable generation with export to the grid, combined heat and power systems, or electricity supply contracts with complex renewable components.

For annual consumption under 500,000 kWh with straightforward grid supply, the calculation remains simple. Focus on accuracy in your consumption data and using current, geographically appropriate emission factors. That foundation will serve you well across the majority of ESG questionnaires you'll encounter.