The aim of the present thesis is the description of the most important electricity generation companies in Hungary and Slovakia in terms of a simulation model, which is able to illustrate the economic impacts of strategic corporate decisions. For that purpose, firstly economic and regulatory framework conditions of the electricity markets are investigated and described. The key market players, their market shares and assets are characterized. As a next step, technical and economic data of the major power producers as well as relevant parameters concerning the electricity industry are implemented into a simulation model, which has been expanded and modified in the course of this master thesis. Finally, three different strategies for the extension of production capacity are examined with regard to their economic effects. These are assessed on the basis of commercial viability. Furthermore the impacts of regulatory intervention on the company are analysed and displayed. The comparison of realistic strategies for the development of the power plant fleet of the Hungarian power generator MVM demonstrates the capability of the model. MVM is the dominant market player in Hungary, holding a diversified portfolio of production technologies comprising coal, natural gas and nuclear power plants; however, additional investments in production capacities are foreseen to be necessary in the coming years. Subject to the underlying assumptions and the applied input data, a nuclear strategy appears preferential to new generation capacities using coal and natural gas from an economic point of view. A supplementary liberalization scenario depicts that a reduction of regulated power sales benefits the economic viability of the company.