Offshore wind farms will play an important role in supplying the increasing energy demand while considering ecological and economic aspects. Especially floating foundations which have a great potential for offshore wind farms in water depths between 40 m up to 200 m and more, will be a major factor. The objective of this paper is to focus on the design of a TLP substructure including the anchoring in the seabed by considering the economic and ecological aspects. One main focus is on economic challenges and the approaches for reduction of the investment costs and the Levelized Cost of Energy. A second focus is on the cumulative energy demand as well on the expected CO2-emissions during the fabrication process. (C) 2018 The Authors. Published by Elsevier Ltd.