OKTE, a.s., as the organizer of the short-term electricity market, organises auctions of guarantees of origin of electricity from renewable energy sources and guarantees of origin of electricity produced by highly efficient combined heat and power generation. These guarantees of origin are issued pursuant to Act No. 309/2009 Coll. for production devices supported by investment aid and production devices receiving operational support in the form of a Feed-in Tariff or Feed-In Premium.
In accordance with the planned amendment to the Operating Rules of OKTE, a.s., effective as of 1 May 2026, producers and energy suppliers will also be able to offer guarantees of origin for sale in the auction, with OKTE, a.s. acting as an intermediary within the trading mechanism. This change requires the deployment of a more complex order-matching algorithm (pay-as-clear) as well as the introduction of a financial deposit.
OKTE, a.s. normally organises auctions at three‑month intervals, but they can be also held once a month if necessary. Any entity holding an account with valid access to the XMtrade®/ZPE information system and having concluded an Agreement on activities related to the issuance and use of guarantees of origin with OKTE, a.s. may participate in the auctions.
Change in Evaluation – Marginal Price
The new matching mechanism for guarantees of origin auctions (pay-as-clear) operates on the principle of creating a single marginal price for each category announced in the relevant auction. Categories are divided according to the type of source and the remaining lifetime at the time of the auction. The objective of the algorithm is to achieve the highest possible social welfare for each category.
The resulting marginal price for each category of guarantees of origin is determined by the lowest price of a partially or fully executed purchase order. In addition to determining the marginal price, the matching process defines the traded volume of orders that entered the matching procedure.
Order Types
Auction participants may submit their orders from the date the auction is announced until the close of order intake on the auction day. For sales, the order type is always Simple, with a specific combination of source type and remaining lifetime of the guarantees of origin; guarantees from multiple production devices of the same type may be included. For each order, the seller specifies a minimum price separately.
For purchase orders, in addition to the Simple type—where the participant specifies the quantity of guarantees and the offered price for a single source type—it is also possible to choose the Variable order type. This may include two or more combinations of source type and lifetime, with a separate offered price defined for each.
In the case of a Variable order, the auction participant may manually set the priority of settlement for individual combinations or allow the system to automatically rank them based on the offered prices. Orders may be modified until the close of order intake. All order types may be fully traded, partially traded, or not traded at all within the auction.
Financial Deposit
A condition for purchasing guarantees of origin in auctions is financial coverage provided in the form of a deposit. The auction participant may submit purchase orders only up to the amount of the deposited financial guarantee. For Slovak entities, VAT at a rate of 23% is automatically added to the amount of each order. VAT is not added to orders submitted by foreign entities. The system dynamically evaluates the remaining deposit amount, with checks performed upon each order submission.
Acceptance of deposits for the upcoming guarantees of origin auction begins on the date the auction is announced, which must be at least 10 days before the auction date. Financial funds must be credited to the bank account for the auction purchase deposit no later than 2 working days before the auction date.
Account for Auction Purchase Deposit
Account number: 2946265957/1100
BIC: TATRSKBX
IBAN: SK45 1100 0000 0029 4626 5957
The deposit is used to cover the purchase of successfully traded guarantees. The remaining part of the deposit, or its full amount in the case of unsuccessful purchase offers, will be returned to the auction participant’s account after the auction is evaluated, as will deposits credited after the specified deposit deadline. The IBAN of this account must be entered via an amendment to the ZPE Agreement through the EDC system (it may be identical to the entity’s primary account).
Before each auction, participants will be assigned a variable symbol that will be unique to one entity and the specific auction. Participants are informed of this symbol along with other details after the announcement of the relevant auction via email notification.
Slovak energy producers will be able to configure individual production devices so that guarantees of origin issued for their production are automatically included in the sales offer in the subsequent auction. A minimum price must be defined.
You can find frequently asked questions (FAQ) about about Guarantees of Origin Auctions at this link.
