The paper deals with a planning of electric energy output produced by different energy sources of an active distribution system. Active distribution system is a wider and simpler concept compared to Microgrid or Minigrid. METHODS. Due to distinguishing energy sources, volatility of an intraday energy prices and free market pricing, a unit commitment at an active distribution system to be considered as an optimization issue. The planning of the economy-based operating strategy is performed using energy market models, linear and non-linear programming as well as Boolean (discrete) algebra. The developed models require for obtaining short-term LCOE including CAPEX-based and OPEX costs for different kind of energy sources. A two-stage optimization procedure provides the minimization of energy costs at the first stage and intraday energy pricing at the second stage. RESULTS. The case study presented in the paper shows the economy for customers up to 22.4 % compared to energy purchased from centralized grid using double-rate tariff, and profit for energy sources up to 58.5 %. A sub-optimization approach provides the economy for customers up to 25.1 % and profit for energy sources up to 65.3 %. CONCLUSIONS. The paper shows that if energy is purchased from centralized grid using retail double-rate tariff, than flexible energy sources provide a great economy potential by reducing load peaks during the provisional hours of grid high prices and energy sales high prices. Customer pricing at an active distribution system to be set using Demand Response principles to obtain the most efficient load graph.