The development of electricity markets is a current topic in European Union because they are complex systems, always developing and bringing new challenges for the experts. Republic of Croatia, as a young member of EU, is inseparably connected with the events in the European scenery. In this study, the complex interdisciplinary topic of electricity markets is aproached on a local and European level. Terms from energetics, finance, statistics, electrical engineering and economy are intertwined. Furthermore, the differences between the systems used in Croatia and systems used in other European countries are shown. Starting with the description of Croatian electric power system in the 1st chapter, it is possible to see the basic energy statistic of Croatia, the state of our infrastructure and the management of the whole electric power system. In the 2nd chapter, the Croatian electricity market is mentioned, with its legal framework. Support systems for renewables and cogeneration are the topic of chapter 3. Here, the support system's influence on the management of the electrical power system is described. In the 4th chapter, the electricity markets in Europe are shown. One of the most important and biggest initiatives of EU, which is dealing with the integration of all European electricity markets, is described in chapter 5. Chapter 6 shows the support systems for renewables in Europe. At the end, in chapter 7, a case study is shown for photovoltaics, using different support systems. This case study serves as a demonstration od distinctions between support systems. Chapter 8 is a conclusion. The goal of this study is to provide the reader with basic information for his further research of interests connected with this subject.