This work is focused on the determination of the benefits of green power plants for industrial sites. Technical concepts for different green power plants for voestalpine Stahl Donawitz GmbH & Co KG, including technical and economic valuation, shall show their possible advantages. The present work is separated in two parts. The first part is concerning with the evaluation of the technical basics of green power plants based on photovoltaic, hydropower, wind power, biomass, biogas, geothermal and solar thermal power. Based on these technical basics, technical concepts for photovoltaic, wind power, hydropower and biomass plants were created. Therefore the local conditions of the company were determined, possible concepts for the installation were created and different technologies and suppliers of green power plants were compared. The second part of this work evaluates the economic conditions of the four investigated green power plants. The investment costs, electricity production costs and subsidies of photovoltaic, wind, hydro and biomass plants were determined. Based on the economic conditions, an economic calculation in form of static investment was conducted in order to investigate the economic relevance of the developed concept for each plant. In addition to the technical and economic evaluations, the aspect of a better image because of the use of electricity production from renewable energy was analyzed. The benefits of photovoltaic, wind power, hydropower and biomass plants are shown by comparing the technical and economic assessments and in consideration of the image of renewable energies.