Guarantees of origin

Article 19 of the Renewable Energy Directive (EU) 2018/2001 sets the rules. A guarantee of origin exists so that a supplier can show final customers the share or quantity of renewable energy in its energy mix and in contracts sold as green. Member states issue one at the request of a renewable producer, with a standard size of 1 MWh. Since the 2023 amendment that size may be divided into fractions, as long as each fraction is a multiple of 1 Wh. No more than one guarantee may be issued for each unit of energy. A guarantee is valid for transactions for 12 months after the energy was produced, and any guarantee not canceled expires at the latest 18 months after production. Issuance, transfer and cancellation are electronic and must follow the CEN-EN 16325 standard. A member state may decide not to issue guarantees to producers that receive support from a support scheme.

A guarantee goes through three stages. It is issued to the producer, transferred to a trader, supplier or final customer, and canceled for a named beneficiary and period. Only cancellation turns it into a claim: until then it is a tradable certificate, and once canceled it cannot be sold again.

In Poland the rules are in Articles 120 to 125a of the Renewable Energy Sources Act. A guarantee of origin is electronic, expressed in MWh, and is the only document that proves renewable origin to a final customer. It carries no property rights and is traded independently of the certificates of origin (świadectwa pochodzenia) of the older support scheme. The President of URE issues it on a producer's application, filed through the distribution or transmission system operator within 30 days of the end of the production covered by the application. Microinstallations cannot apply. The registry is run by a commodity exchange, in practice the Polish Power Exchange (TGE), and a transfer takes effect when it is entered in the registry. A supplier may inform a final customer about origin only after the guarantee has been canceled, and the registry confirms the cancellation within 10 working days. The registry operator also publishes the annual residual mix: the energy left after canceled guarantees are taken out.

For a procurement, supply or carbon reporting system, guarantees of origin need their own records next to the energy records. Requirements worth specifying:

• Guarantees live in their own ledger. Volume, energy source, plant, country, production period, issuing registry, seller and price are recorded separately from energy contracts and never netted against MWh of delivered energy automatically.
• Status drives what the number means. Held, transferred, canceled and expired guarantees count differently, and only canceled ones support a green claim.
• The validity clock is tracked. The system should warn before guarantees approach the end of their 12-month transaction window, and stop counting expired ones.
• Claims use canceled guarantees matched to a period. A carbon footprint or a green share is calculated from guarantees canceled for that customer and that consumption period, and the uncovered part uses the residual mix, not the national average.
• Price data and production periods use different date conventions. Production periods, purchase dates and price dates have to be mapped explicitly, because a shift of one day in price data distorts every report built on it.
• Volumes are stored without assuming whole MWh. EU law already allows fractions of 1 MWh, which opens the way to finer matching against consumption.
• Guarantees and certificates of origin are different products and need different data models, even when the same team buys both.

Since 2020 we have built a platform for Enerace, an energy procurement advisory. Guarantees of origin were added to it as a commodity in 2021. The same year we built a carbon footprint module that calculates emissions from the fuel mix of each country and each seller in a given year.

In 2025 we added recording of guarantee of origin purchases, the seller of each purchase and a carbon footprint view that presents the data together with guarantees of origin. The same year we fixed wrong date shifts in guarantee of origin price data.