## 5 Conclusions  
The aim of this work is to develop an economic evaluation of an innovative floating offshore wind platform whose main material is concrete: The SATH(r) platform. The floating offshore wind platforms analyzed in previous studies consider concepts built on steel (for instance: WindFloat, TLP or Hywind platforms). However, concrete can have some advantages when comparing its properties with steel ones. These include the installation process, the absence of corrosion, easiness of building, etc. The SATH(r) platform has an easier way of installing comparing to other concrete platforms.  
The paper developed a method to calculate the costs of the platform and the economic parameters to determine the economic feasibility of the farm. In order to determine the costs of the platform it is important to know its main components, which are different from the previous steel concepts: twin horizontal floaters stiffened with diaphragm walls with conical ends and linked with bar frames, lower tower section linked to floaters, pitch-roll plate linked to floaters and a single point mooring. In addition, considering the maintenance process, SATH(r) platform can offer a significative advantage with respect to other floating solutions, or even to the fixed systems, in case of big repairs where singular maritime means such as jack-up rigs and floating cranes could be needed. In this context, SATH(r) platform can be easily disconnected and maintained. In addition, SATH(r) platform uses concrete, that is a material not requiring maintenance, in all parts of the platform in contact with sea water.  
This case of study has analyzed a farm of 500 MW located in Figueira da Foz (Portugal) and with several alternatives depending on the electric tariff and the capital cost.  
Results show if a farm of these characteristics is feasible in economic terms and which parameters its profitability depend on. Moreover, scenarios with higher electric tariff give better economic results for the same costs.  
This paper is important in that it offers a new approach of the traditional floating offshore wind structures, which can represent a path towards the future of the floating offshore renewable energy technologies. The new concept analyzed in the paper, the concrete SATH(r) platform, can represent the future of the floating offshore wind sector if it achieves economic competitiveness in relation to the present steel floating platforms that are traditionally developed from concepts based in the fossil fuel sector.  
Figure 7: Net Present Value (NPV) for a farm with SATH® platforms.  
**Author Contributions:** Introduction: E.B.-S., D.C.-I., A.F.-V., A.M., I.L.-G., C.A.-F., L.C., L.C.-S.; method: E.B.-S., D.C.-I., A.F.-V., L.C.-S.; case study: A.M., L.C.-S.; results: E.B.-S., D.C.-I., A.F.-V., A.M., I.L.-G., C.A.-F., L.C.-S.; conclusions: D.C.-I., A.F.-V., L.C.-S.; supervision: [PERSON]-S.; preparation and scientific research: L.C.-S., A.F.-V., E.B.-S., D.C.-I. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by EAPA_344/2016 ARCWIND project, co-financed by the European Regional Development Fund though the Interreg Atlantic Area Programme.  
**Acknowledgments:** The authors would like to thank Saitec for the information provided.  
**Conflicts of Interest:** The authors declare no conflict of interest.