Electricity · heat · contractual instruments
Scope 2 reporting software: two methods, one meter
Scope 2 reporting software calculates emissions from the electricity, heat, steam and cooling a company buys.
In the UK the hard part is not the arithmetic but the method: location-based for UK SRS, and both methods under the GHG Protocol.
The method itself is explained on the Scope 2 emissions guide.
Which method
Which Scope 2 method does each UK rule need?
The three main UK uses ask for different things.
| Rule | Location-based | Market-based |
|---|---|---|
| UK SRS S2 | Required | Not required; information on contractual instruments is |
| GHG Protocol Scope 2 Guidance | Required | Also required where contractual instruments exist |
| SECR guidance | Encouraged where a company does not dual report | Dual reporting is the stated preferred approach |
REGOs
How should Scope 2 software handle REGOs and green tariffs?
Ofgem issues one REGO per megawatt-hour of eligible renewable output, and REGOs can be traded with or without the electricity (Ofgem).
A REGO-backed tariff therefore changes a market-based figure, not a location-based one.
The GHG Protocol sets quality criteria for contractual instruments, including that they are tracked and retired on the company’s behalf and match the period of consumption.
Scope 2 software should hold each certificate, its volume, period and retirement evidence against the meter it covers.
Residual mix
What factor should Scope 2 software use for unmatched electricity?
In a market-based figure, electricity not covered by a contractual instrument should use a residual mix factor.
The AIB’s 2025 residual mix for Great Britain is 280.64 gCO2/kWh, and the AIB notes that official residual mixes are in principle published by national authorities (AIB).
Ask the vendor which residual mix it uses, from which year, and whether you can change it.
For location-based figures, UK reports use the DESNZ factor set for the reporting year (DESNZ).
Changes ahead
Will Scope 2 rules change?
The GHG Protocol is revising its Scope 2 Guidance, but no revised standard is in force (GHG Protocol).
A tool built today should keep the meter data, the instruments and the factors separate, so either method can be re-run when the rules change.
The demonstration
What should you test before buying?
Bring one year of meter data and one REGO-backed contract.
Software demo · evidence check
Scope 2 demo coverage
Tick a test only when the vendor has demonstrated it with a representative record and shown the evidence or export.
0 of 5 tests demonstrated (0%). This is a checklist result, not a score for the vendor.
Still to test: Produce location-based Scope 2 with the DESNZ factor year named; Produce market-based Scope 2 using the REGOs and a named residual mix; Show each certificate’s volume, period and retirement evidence; Keep UK kWh visible for SECR; Re-run both figures after changing a factor, without retyping.
Frequently asked
Scope 2 reporting software, answered
What is Scope 2 reporting software?
Software that calculates emissions from purchased electricity, heat, steam and cooling, on a location basis, a market basis or both, and keeps the meter data and contractual evidence behind each figure.
Does UK SRS require market-based Scope 2?
No. UK SRS S2 requires location-based Scope 2 and information about contractual instruments. It does not require dual reporting.
Does the GHG Protocol require market-based Scope 2?
Yes, where a company operates in markets with contractual instruments such as REGOs.
Its Scope 2 Guidance then requires both a location-based and a market-based figure.
Is a REGO-backed tariff zero emissions?
Only in a market-based figure, and only if the instruments meet the GHG Protocol’s quality criteria.
The location-based figure is unchanged by a REGO.
Sources
Primary sources
Every figure, date and status on this page traces to the instrument’s owner.
Secondary commentary is never the source for a number.
- DBTUK SRS S2 Climate-related Disclosures
- GHG ProtocolScope 2 Guidance
- GHG ProtocolCorporate Standard
- OfgemRenewable Energy Guarantees of Origin (REGO)
- AIBEuropean Residual Mixes 2025
- DESNZGreenhouse gas conversion factors 2026
- DESNZ and DefraEnvironmental Reporting Guidelines including SECR
- LegislationSI 2008/410 Schedule 7 Part 7A (SECR)
- LegislationSI 2008/410 Schedule 7 Part 7 (quoted companies)
- GHG ProtocolStandard development updates