Scope 2 — emissions from the electricity, steam, heating, or cooling you purchase — is one of the most common items in ESG questionnaires. For most small and mid-sized suppliers, electricity is the whole of it.
| First question | Short answer |
|---|---|
| What is the formula? | kWh consumed × grid emission factor (kg CO2e/kWh) ÷ 1,000 = metric tons CO2e. |
| Where does the kWh come from? | The consumption line on twelve months of electricity bills, summed. |
| Location-based or market-based? | Report location-based first. Add market-based if you buy renewable electricity or certificates. |
| Which factor? | The current published factor for the grid where the electricity is consumed. |
| What evidence do I keep? | Bills, the factor source, the calculation file, and any renewable certificates. |
The calculation
Electricity consumption (kWh) × emission factor (kg CO2e/kWh) = emissions (kg CO2e)
Divide by 1,000 for metric tons. That is the figure questionnaires ask for.
Worked example
A facility consumed 50,000 kWh in 2025. The grid emission factor is 0.485 kg CO2e/kWh (an example value).
- 50,000 kWh × 0.485 = 24,250 kg CO2e
- 24,250 ÷ 1,000 = 24.25 tCO2e
The free Scope 2 calculator runs the same calculation with a current factor for your grid.
Finding the consumption figure
Electricity bills show total kWh consumed. If the bill splits consumption by time period (peak, off-peak) or by meter, sum them for the monthly total. Add twelve months for the annual figure.
Facilities in different countries or grid regions need separate calculations with the appropriate factor for each.
Location-based versus market-based
The GHG Protocol defines two methods. Many questionnaires ask for both.
Location-based. Uses the average emission intensity of the grid where the electricity is consumed. It reflects the physical generation mix. Use national or regional grid factors. Do not adjust for renewable purchases or contracts.
Market-based. Reflects the electricity you have contractually chosen: green tariffs, renewable energy certificates, or supplier-specific rates. Without renewable purchases, the market-based figure equals the location-based one. With certificates covering 100% of consumption, market-based Scope 2 can be zero while location-based is unchanged. Dual reporting shows both the contractual choice and the grid impact.
Where grid emission factors come from
International Energy Agency. National electricity factors by country, widely accepted for location-based calculation, updated regularly.
National government sources. UK: DEFRA conversion factors (annual). USA: EPA eGRID (by subregion, more granular than a national average). EU: European Environment Agency factors. Australia: National Greenhouse Accounts Factors.
Utility-specific factors. Some suppliers publish their own rate; usable for market-based calculation under a direct supply contract.
Multiple locations
Calculate each site separately with its own grid factor (example values):
- Facility A (UK): 30,000 kWh × 0.212 kg CO2e/kWh = 6.36 tCO2e
- Facility B (Germany): 20,000 kWh × 0.348 kg CO2e/kWh = 6.96 tCO2e
- Total Scope 2: 13.32 tCO2e
Report the total; keep the per-site figures for questionnaires that ask for a geographic breakdown.
Renewable certificates and green power
Renewable energy certificates (Guarantees of Origin in Europe) are tradable certificates showing that one MWh of renewable electricity was generated. Buying them allows a renewable claim in the market-based calculation.
With certificates for 50,000 kWh (50 MWh) and consumption of 50,000 kWh:
- Location-based Scope 2: 24.25 tCO2e (unchanged)
- Market-based Scope 2: 0 tCO2e (certificates carry a zero factor)
Certificates must match the reporting year and the geographic market. Vintage matching rules matter for a credible claim.
Common errors
- Unit mismatch. kWh and MWh mixed, or a factor in the wrong units.
- Outdated factor. A factor from a year before the reporting period.
- Wrong geography. A national factor where a regional one exists.
- Double counting. On-site solar generation is outside the scopes; purchased electricity is Scope 2. Do not put electricity in Scope 1.
Documentation
Questionnaires may ask for support. Keep:
- Electricity bills showing consumption
- The emission factor source (publication, year, region)
- The method used (location-based and/or market-based)
- Certificates, if applicable
ESG Passport stores this documentation alongside the calculated figure, so evidence is at hand when a customer asks.
When it gets complex
Most small suppliers can use the basic approach. Expert help becomes relevant with on-site renewable generation exporting to the grid, combined heat and power, or supply contracts with complex renewable components.
For annual consumption under 500,000 kWh with straightforward grid supply, the calculation stays simple. Accuracy in the consumption data and a current, geographically appropriate factor are what matter. If the questionnaire also asks for Scope 1, the free carbon calculator covers fuel and vehicle emissions alongside electricity.
What customers accept
Most supplier questionnaires accept annual purchased electricity multiplied by a current, geography-specific emission factor. Show the reporting year, total kWh or MWh, the factor source, and whether the figure is location-based or market-based. If you buy certificates or Guarantees of Origin, keep them separate from the utility bills so the market-based claim can be checked.
If unsure which method the customer wants, provide the location-based figure first and state whether a market-based figure is available. That gives a conservative baseline while preserving recognition of renewable procurement where their methodology allows.
Evidence folder
One folder per reporting year: electricity bills, renewable certificates, emission factor source documents, the calculation file. Consistent names, for example 2026-electricity-bills-site-a.pdf and 2026-scope-2-calculation.xlsx. This prevents the common problem of a correct number nobody can trace six months later.