On the issued electricity bills for end consumers and in their promotional materials electricity suppliers are obliged to disclose the shares of individual energy sources used to produce the supplied electricity in the preceding year. These shares must be published in a table, in which the shares of individual production sources are expressed in a percentage and by a pie chart. Consumers must also be provided with information on CO₂ emissions and the radioactive waste resulting from production sources. When a supplier is offering special electricity products, for example "100 percent energy from solar power plants" must to the customers, buying this product, indicate the share in the whole company structure, and in addition, the structure, which refers to the specific electricity product.

The methodology for determining the shares of production sources and the manner of their presentation is set by the Act laying down the mode of determining shares of individual production sources and the manner of their presentation. This Act, which is force from September 2013, determines that the shares of electricity produced from renewable sources can be proved only through cancellation of Certificates of Origin, while the shares of other sources can be proved through the national and European residual mix.