A guarantee of origin (GO) is an electronic certification attesting the renewable origin of energy. It is provided for by Article 19 of Directive (EU) 2018/2001, has a standard size of 1 MWh and in Italy is issued by GSE for the electricity, renewable gas and thermal carriers. It serves to demonstrate to final customers that a given quantity of energy was produced from renewable sources. It does not change the energy reaching the meter, which remains that of the grid: it establishes who can claim the renewable origin of that megawatt-hour.
From producer to cancellation
- Qualification. The producer asks GSE for the IGO qualification of the plant, valid for five years unless significant changes occur.
- Issuance. For every MWh produced from a renewable source GSE issues a title; only one GO may exist for each unit of energy.
- Transfer. GOs are traded on the GME platforms, market (M-GO) and bilateral (PB-GO), and on the international platform of the AIB (Association of Issuing Bodies). The GOs of plants whose energy is withdrawn by GSE are allocated through five auctions a year.
- Cancellation. Twelve months after production a GO can no longer be transferred, only cancelled by its holder within the following six months and in any case no later than 31 March of the second year after the year of production. Expired GOs flow into the residual mix.
Prices change with source, production period and demand: GSE publishes the outcome of every auction.
GOs and "green" supply
Suppliers must tell customers, on the bill and in information material, the composition of their energy mix (fuel mix), calculated taking GOs into account. A supplier presenting the energy it sells as renewable must demonstrate it with guarantees of origin. GOs can also come together with the energy, for example within a PPA, if the contract so provides.
How they enter the emissions inventory
The GHG Protocol Scope 2 Guidance requires emissions from purchased electricity to be reported in two ways: location-based, with the average grid factor, and market-based, with the factors of contractual instruments, including GOs. To be usable a GO must meet quality criteria: be the only instrument carrying that attribute, be cancelled on behalf of the business, refer to a period as close as possible to that of consumption and come from the same market in which the business consumes. Those without contractual instruments use the residual mix.
The guidance is under revision: the public consultation ran from 20 October 2025 to 31 January 2026 and, as of October 2026, the official page does not yet show a revised text. It is worth following the outcome before setting multi-year targets.
For a business: what to look at
When they are worth considering
When customers, the lead company of the supply chain, banks or tenders ask for proof of the origin of electricity, or when the business has set itself a target on the Scope 2 of its carbon footprint.
What is needed
- the annual consumption in MWh of every POD;
- a contractual clause stating quantity, source and production period of the GOs;
- the statement that cancellation has taken place in favour of the business.
Typical mistakes
- covering part of consumption and claiming 100%;
- using GOs referring to a period far from that of consumption;
- selling the GOs of one's own plant and still claiming the self-produced energy as renewable;
- treating the electricity GO as an offset: it concerns purchased electricity, not gas or supply-chain emissions.
What can and cannot be claimed
A business can state that the electricity purchased in a given year is covered, for a precise share, by cancelled guarantees of origin, and report the corresponding market-based Scope 2 next to the location-based one, which does not change. It cannot state that the factory is physically powered by renewable energy, nor present the company or its products as "zero emissions". Since 27 September 2026 the rules of Directive (EU) 2024/825 apply, transposed in Italy by Legislative Decree 30/2026: in communications to consumers, generic environmental claims that cannot be demonstrated and claims of neutral impact based on the offsetting of emissions are prohibited.
To document the share covered there is also the Attestato Green User, a statement based on official GSE data; the overall picture is part of the energy sustainability service for businesses.
If you want to check what your company can claim about the energy it buys, IPGS ENERGY examines it as a consultant, not as a supplier: Request a conversation.
Sources
- GSE — Guarantee of origin (Garanzia d'origine) (accessed 10 October 2026)
- GSE — GO auctions (Aste GO) (accessed 10 October 2026)
- GSE — Fuel mix (accessed 10 October 2026)
- EUR-Lex — Directive (EU) 2018/2001, Article 19, consolidated text (accessed 10 October 2026)
- AIB — Renewable Energy Guarantees of Origin (accessed 10 October 2026)
- GHG Protocol — Scope 2 Guidance (accessed 10 October 2026)
- EUR-Lex — Directive (EU) 2024/825 (accessed 10 October 2026)
- Normattiva — Legislative Decree no. 30 of 20 February 2026 (accessed 10 October 2026)
Informational content by IPGS ENERGY. Information is reviewed as of the stated update date and does not replace a contractual, tax or regulatory assessment specific to an individual business.
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