The electricity market in Croatia is still going through its liberalization process that officially started ten years ago. But since 2013. it can be stated that there is actually a liberalised market by entering several alternative electricity suppliers offering more favorable electricity prices than the dominant HEP supplier. For the past couple of years, renewable energy sources have become increasingly important factor in electricity generation and their share is growing year-by-year. All the electricity suppliers in Croatia who appear in the market are mandatory to buy off such "green energy“ at far higher prices than the market prices. Increasing the share of renewable energy sources also increases the volume that suppliers have to buy off and this way of doing business in the Croatia puts in front of suppliers a big challenge. Every year the number of active electricity suppliers is decreasing. HROTE (Croatian Energy Market Operator) is responsible for collecting and paying for renewable resources. It is collected from two sources, both from the supplier and from the customers, as a separate item on the electricity bill. Renewable energy sources with rising electricity prices force suppliers to withdraw from the market and the market is slowly returning to the monopoly that is the worst case for the consumer. Such forced purchase directly affects the supplier's work planning and its trading strategies and directly increases the cost that the supplier has to allocate for the delivered electricity. Suppliers suggest that such electricity should be put to market through CROPEX (Croatian Electricity Exchange) and is thus available to everyone at market prices. By comparing the Slovenian and Croatian electricity markets, it can be concluded that Slovenia has been selling electricity from renewable sources for several years on the market and slovenian electricity suppliers are not mandatory to buy off green energy at higher prices.