Market participant, who wants to operate as a supplier in the Slovenian retail market, has to be registered as an electricity supplier in any of the countries of the European Union. Prior to starting the activity, a supplier must become a member of the Balance Scheme and fulfil the obligations set by the Energy Act and executive regulations. This mainly refers to the requirements regarding the functional unbundling of the activities of a supplier from distribution activities in related undertakings.

An electricity supplier concludes open contracts with consumers or small electricity producers. In open contracts, the amounts of supplied and consumed electricity are not pre-determined; the actual consumption is taken into account. For the imbalance settlement, the suppliers are obliged to submit to the Market Operator the operational forecast for their delivery points within the time periods determined by the Rules on the operation of the electricity balancing market.