The authors investigate the investment requirements of the energy economy, especially for the Federal Republic Germany, but also for parts of the world. Possibilities for financing are shown which can be considered as assured, under certain conditions. Included are the investments and the capital requirements for the fossil energy-carriers (coal, brown coal, oil, natural gas), for the electricity economy and for the regenerativ energy sources (e.g. tidal energy, wind, solar radiation). The last chapter deals with financing the necessary investments in the energy sector, considering the financing structure, financial problems of individual branches and the development of the credit volume.