A preliminary parametric techno-economic study of offshore wind floater concepts

Abstract

The rapid development of the offshore wind industry is leading stimulating interest in exploiting wind resources in deeper waters and farther offshore, requiring alternative support structures including floating foundations. Currently, a number of different concepts are under development aiming to become commercialised for deployment in the near future. One of the main barriers against their widespread adoption is cost, which is currently considerably higher than fixed support structures. This paper investigates through a parametric study the total mass and cost of three floater concepts: spar, barge and semi-submersible, particularly focusing on the material and manufacturing costs. The manufacturing cost was approached by means of manufacturing complexity factors, whose values were obtained through a survey among experts in floating offshore wind. Key finding of this work, under the defined conditions, is the fact that semi-sub structures with steel as structural material appeared to be the most expensive configuration, spar costs decrease with higher draft values, due to the reduction in the ballast mass, while the barge solution is potentially the lowest cost alternative. Nevertheless, risks and benefits of different configurations should also be considered alongside, as they could lead to savings throughout the service life of the asset.