Geothermal energy provides from the point of climate protection an interesting alternative to the fossil fuels. Therefore it moves more into focus of the European energy strategy. The purpose of this master thesis is to perform an ecological and economic analysis of a geothermal project in the Upper Austrian city Gmunden. Moreover, this work also includes an evaluation of the geothermal potential and their possible forms of applications. The results of this analysis are presented in a Business Plan. The first part of this thesis outlines the two topics, geothermal energy and Business Plans, according to the literature. For this the technical, geological, ecological and legal aspects of deep geothermal energy are analyzed and the planning, the generally valid forms and aspects of Business Plans are shown. The second, empirical part presents the Business Plan of the geothermal project in Gmunden. In order to design the Business Plan, which is adopted for the criteria of a hydro-geothermal project, the main aspects for a successful project are considered. The results of the ecological analysis show that the geothermal energy would contribute to a large reduction potential of CO2 emissions, because of the fact that Gmunden is supplied primarily by gas. The economic evaluation was performed with safety factors on the cost side and minimal consumer structure on the income side. Therefore, for the first stage of expansion mainly major consumers are connected to the district heating. From the current point of view a successful implementation of the project appears not reasonable, but under changed conditions, which could be definitely expected in future, geothermal energy in Gmunden represents an interesting alternative.