Croatian energy market operator ltd is defined in the Republic of Croatia as an energy operator performing the activity of organizing the electricity market and the gas market as a public service under the supervision of the Croatian Energy Regulatory Agency. Also the company's activity is to encourage the production of electricity from renewable sources of energy, cogeneration, and the production of biofuels for transport. The governments of the EU member states have become aware of the need to support the integration of the gas market. As a result, long-term investments in the gas system are needed, whereby the international connection of the gas pipeline system, i.e. the development of the European gas infrastructure, including gas pipelines, interconnections, gas storage sites as a natural gas market spot, is an important factor. Croatian energy market operator is imposing itself on the new gas market conditions as a factor for gradually taking over the core role of the future gas hub in Croatia and the gas exchange in southern Europe. According to the Law on Renewable Energy and High-Efficiency Cogeneration, Croatian energy market operator is authorized to trade electricity in the electricity market in a clear and impartial way to ensure the sale of electricity in accordance with the planned production of the ECO balance group. Sales models represent a balanced approach to distributing and minimizing the risks that Croatian energy market operator takes over and, as modes of delivery, fit a wide range of market participants. The commercial terms of the auction for guaranteed and nonguaranteed deliveries are aligned with the market practice and the pricing modalities are set in such a way as to reflect the relevant reference prices of electricity in the Republic of Croatia, and in such a way as to minimize the effects of undesirable fluctuations in the price of electricity.