The National Residual Mix represents an overview of the share of variety of individual energy sources and serves the electricity supplier for the purposes of determining the shares of individual energy sources on its total fuel mix and presentation of these shares on a document pursuant to the Decree on Delivery Billing No. 70/2016 Coll. (Section 6 (3) (a), Section 7 (3) (a) or (9) (6)) for that part of the electricity supply to its customers, which in not proven by the guarantees of origin in accordance with the applicable legislation and with the Business Terms of OTE, a.s., for the power market.

An electricity supplier can increase the share of a selected energy source in this mix only if he can prove the electricity supply by cancelled guarantees of origin to the benefit of that customer or group of customers.

For the purpose of establishing the National Residual Mix, the Residual Mix Methodology is used. The Residual Mix Methodology was developed by the project Reliable Disclosure Systems for Europe (RE-DISS), secured by the European Commission´s Intelligent Energy-Europe (IEE) programme. The document is available on the website of the Association of Issuing Bodies (AIB).