If you buy electricity with guarantees of origin, your inventory has to carry two scope 2 figures, not one. The GHG Protocol Scope 2 Guidance requires companies operating in markets where contractual instruments with product or supplier-specific data exist to account for and report scope 2 emissions both ways, labelling each result by method: one using the location-based method and one using the market-based method.
The usual mistake is not in the maths, it is in the presentation: publishing only the low number, the market-based one, without saying which it is. That is what a verifier sends back.
The two methods, side by side
| Location-based | Market-based | |
|---|---|---|
| What it reflects | The average intensity of the grid where you consume | What you have contracted for |
| Factor used | Average grid or national mix factor | Supplier factor or contractual instrument factor |
| Effect of a guarantee of origin | None | Lowers the result |
| What it is good for | Comparing sites and understanding physical grid exposure | Reflecting purchasing decisions and tracking them over time |
| Can it be omitted | No | No, if you operate in a market with contractual instruments |
Both numbers are correct and they measure different things. The location-based one tells you where you are; the market-based one, what you decided. Publish only one and the reader cannot tell which. The definition of scope 2 emissions and the general split by scope are covered in the article on the differences between scope 1, 2 and 3 emissions, within the wider method for calculating a carbon footprint.
What a guarantee of origin is and who issues it in Spain
The CNMC, Spain's markets and competition authority, is responsible for the guarantees of origin system and for issuing and managing the guarantees generated. The regime is set out in CNMC Circular 1/2018.
Four features determine whether you can use one in your scope 2:
- What it certifies. It is an electronic accreditation that a given number of megawatt hours produced at a plant, in a defined time period, were generated from renewable sources or high-efficiency cogeneration.
- Unit. The megawatt hour. One guarantee, one megawatt hour.
- Expiry. Guarantees issued or imported for energy generated in production month m automatically expire in month m+12.
- Redemption. This is the assignment of the guarantees to an electricity consumer identified by its supply point code (CUPS), and it must be done before 10 March of the following year.
That last point is what separates a usable guarantee from a marketing line: if the guarantee has not been redeemed against your supply points, it does not evidence your consumption. Electricity labelling, which is where the system turns into the published mix per retailer, is governed by CNMC Circular 2/2021.
The GHG Protocol quality criteria
The Scope 2 Guidance does not accept just any piece of paper. It sets eight quality criteria that every contractual instrument must meet to be a reliable data source for the market-based method. The ones that generate most discussion in practice:
- The instrument has to convey the attributes of the generation, not just the energy.
- It has to be uniquely tracked, redeemed or retired, and claimed only once by a single consumer. Nobody else can claim those same megawatt hours.
- It must relate to a period as close as possible to the reporting period. A certificate from three years ago does not serve this year's inventory.
- It must come from the same market or grid boundary in which the electricity was consumed. Buying certificates in one country to justify consumption in another does not meet the criterion.
Renewable energy certificates in other markets work on the same logic under different names; the entry on renewable energy certificates (RECs) sets out the equivalences.
How this plays out in the Spanish registry
In Spain the practical translation is direct. The carbon footprint registry establishes that indirect emissions from electricity consumption must in every case be calculated using the electricity mix factors the registry provides, which are the ones published by the CNMC.
The rule, in two lines:
- If your retailer appears in the list of retailers with guarantees of origin, you apply its factor, which already reflects the effect of those guarantees.
- If it does not appear, or you do not know it, you apply the generic "Otras" factor.
In other words, the effect of the guarantee reaches you through your retailer's factor, not as a separate deduction you apply yourself. Confusing those two routes is the origin of nearly every double count.
A PPA is not a guarantee of origin
A long-term power purchase agreement is a supply contract or a financial contract, depending on the type. On its own it does not evidence the renewable attribute of your consumption.
What makes a PPA reduce your market-based scope 2 is the associated contractual instrument, that is the guarantees of origin or certificates the contract transfers to you and that are redeemed in your name. If the PPA does not come with those instruments, or the generator sells them to another buyer, the contract may make financial sense but it will not change your inventory. Before signing, ask explicitly who keeps the guarantees.
The four most frequent double counts
- Retailer factor plus your own deduction. Applying the reduced factor of a retailer with guarantees and then also subtracting the renewable energy contracted as an additional adjustment.
- Unredeemed guarantees. Claiming a volume of guarantees that the retailer has not assigned to your supply points.
- Self-consumption counted twice. Self-consumed energy does not buy electricity from the grid, so it generates no scope 2. Deducting it again with certificates counts it twice.
- Mixed markets. Backing Spanish consumption with certificates from another country, breaching the market boundary criterion.
What Royal Decree 214/2025 and the ESRS require
Royal Decree 214/2025 requires companies in its scope to calculate their scope 1 and 2 carbon footprint, with scope 3 voluntary, and to hold a reduction plan with a five-year horizon and quantified targets. Within that calculation, scope 2 is resolved with the registry's factors, as described above.
Under the European framework, the split of scope 2 into both methods remains in the ESRS climate standard after the 2026 revision. Anyone reporting under ESRS will keep publishing both figures. How buying renewable electricity fits into a real reduction pathway, rather than an accounting one, is covered in the article on carbon footprint reduction plans. If you are also weighing investment in your own generation, it is worth looking at the tax deductions for renewable energy in Spain.
The Scope 2 Guidance revision: where it stands
The GHG Protocol has a revision of the 2015 Scope 2 Guidance under way. Public consultation on that document opened on 20 October 2025 and closed on 31 January 2026. In parallel, the GHG Protocol and ISO are co-developing a consolidated corporate standard bringing together the scope 1, scope 2, scope 3 and market instruments workstreams.
What matters for you: there is no final published version. The current standards remain in effect until otherwise communicated, and transition periods will be decided when the revised ones are published. Any content presenting a new Scope 2 Guidance as current rule is ahead of the facts. The sensible move is to document your present method well and not rebuild your accounting on a draft.
Frequently asked questions
Do I have to publish both scope 2 figures?
Yes, if you operate in a market where contractual instruments with supplier-specific data exist. The GHG Protocol requires accounting for and reporting scope 2 under both methods, with each result labelled.
Does a guarantee of origin lower my location-based scope 2?
No. The location-based method uses the average grid factor and is unaffected by what you have contracted.
By when can I redeem a year's guarantees?
Redemption must be done before 10 March of the following year, and guarantees expire automatically in the twelfth month after their production month.
Can I use guarantees from another country for consumption in Spain?
That would not meet the GHG Protocol market boundary quality criterion, which requires the instrument to come from the same market in which the electricity was consumed.
Does a PPA take my scope 2 to zero?
Only if the contract transfers the associated contractual instruments to you and they are redeemed in your name meeting the quality criteria. The contract alone does not evidence the attribute.
Has the Scope 2 Guidance already changed?
No. The revision is under way, with public consultation closed on 31 January 2026, and the 2015 guidance remains the current reference.
Getting scope 2 right is mostly a matter of keeping the mapping between each supply point, its retailer and its redeemed guarantees up to date. Our carbon footprint solution holds that relationship and calculates both figures at once, without double counting the saving.
